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Sample records for multi-wavelength spatial led

  1. Multi-wavelength Spatial LED illumination based detector for in vitro detection of Botulinum Neurotoxin A Activity

    PubMed Central

    Sun, Steven; Francis, Jesse; Sapsford, Kim E.; Kostov, Yordan; Rasooly, Avraham

    2010-01-01

    A portable and rapid detection system for the activity analysis of Botulinum Neurotoxins (BoNT) is needed for food safety and bio-security applications. To improve BoNT activity detection, a previously designed portable charge-coupled device (CCD) based detector was modified and equipped with a higher intensity more versatile multi-wavelength spatial light-emitting diode (LED) illumination, a faster CCD detector and the capability to simultaneously detect 30 samples. A FITC/DABCYL Förster Resonance Energy Transfer (FRET)-labeled peptide substrate (SNAP-25), with BoNT-A target cleavage site sequence was used to measure BoNT-A light chain (LcA) activity through the FITC fluorescence increase that occurs upon peptide substrate cleavage. For fluorescence excitation, a multi-wavelength spatial LED illuminator was used and compared to our previous electroluminescent (EL) strips. The LED illuminator was equipped with blue, green, red and white LEDs, covering a spectrum of 450-680 nm (red 610-650 nm, green 492-550 nm, blue 450-495 nm, and white LED 440-680 nm). In terms of light intensity, the blue LED was found to be ~80 fold higher than the previously used blue EL strips. When measuring the activity of LcA the CCD detector limit of detection (LOD) was found to be 0.08 nM LcA for both the blue LED (2 s exposure) and the blue EL (which require ≥60 s exposure) while the limits of quantitation (LOQ) is about 1 nM. The LOD for white LED was higher at 1.4 nM while the white EL was not used for the assay due to a high variable background. Unlike the weaker intensity EL illumination the high intensity LED illumination enabled shorter exposure times and allowed multi-wavelength illumination without the need to physically change the excitation strip, thus making spectrum excitation of multiple fluorophores possible increasing the versatility of the detector platform for a variety of optical detection assays. PMID:20498728

  2. Hyperspectral fluorescence imaging with multi wavelength LED excitation

    NASA Astrophysics Data System (ADS)

    Luthman, A. Siri; Dumitru, Sebastian; Quirós-Gonzalez, Isabel; Bohndiek, Sarah E.

    2016-04-01

    Hyperspectral imaging (HSI) can combine morphological and molecular information, yielding potential for real-time and high throughput multiplexed fluorescent contrast agent imaging. Multiplexed readout from targets, such as cell surface receptors overexpressed in cancer cells, could improve both sensitivity and specificity of tumor identification. There remains, however, a need for compact and cost effective implementations of the technology. We have implemented a low-cost wide-field multiplexed fluorescence imaging system, which combines LED excitation at 590, 655 and 740 nm with a compact commercial solid state HSI system operating in the range 600 - 1000 nm. A key challenge for using reflectance-based HSI is the separation of contrast agent fluorescence from the reflectance of the excitation light. Here, we illustrate how it is possible to address this challenge in software, using two offline reflectance removal methods, prior to least-squares spectral unmixing. We made a quantitative comparison of the methods using data acquired from dilutions of contrast agents prepared in well-plates. We then established the capability of our HSI system for non-invasive in vivo fluorescence imaging in small animals using the optimal reflectance removal method. The HSI presented here enables quantitative unmixing of at least four fluorescent contrast agents (Alexa Fluor 610, 647, 700 and 750) simultaneously in living mice. A successful unmixing of the four fluorescent contrast agents was possible both using the pure contrast agents and with mixtures. The system could in principle also be applied to imaging of ex vivo tissue or intraoperative imaging in a clinical setting. These data suggest a promising approach for developing clinical applications of HSI based on multiplexed fluorescence contrast agent imaging.

  3. Effect of multi-wavelength irradiation on color characterization with light-emitting diodes (LEDs)

    NASA Astrophysics Data System (ADS)

    Park, Hyeong Ju; Song, Woosub; Lee, Byeong-Il; Kim, Hyejin; Kang, Hyun Wook

    2017-06-01

    In the current study, a multi-wavelength light-emitting diode (LED)-integrated CMOS imaging device was developed to investigate the effect of various wavelengths on multiple color characterization. Various color pigments (black, red, green, and blue) were applied on both white paper and skin phantom surfaces for quantitative analysis. The artificial skin phantoms were made of polydimethylsiloxane (PDMS) mixed with coffee and TiO2 powder to emulate the optical properties of the human dermis. The customized LED-integrated imaging device acquired images of the applied pigments by sequentially irradiating with the LED lights in the order of white, red, green, and blue. Each color pigment induced a lower contrast during illumination by the light with the equivalent color. However, the illumination by light with the complementary (opposite) color increased the signal-to-noise ratio by up to 11-fold due to the formation of a strong contrast ( i.e., red LED = 1.6 ± 0.3 vs. green LED = 19.0 ± 0.6 for red pigment). Detection of color pigments in conjunction with multi-wavelength LEDs can be a simple and reliable technique to estimate variations in the color pigments quantitatively.

  4. Lensless phase microscopy and diffraction tomography with multi-angle and multi-wavelength illuminations using a LED matrix.

    PubMed

    Zuo, Chao; Sun, Jiasong; Zhang, Jialin; Hu, Yan; Chen, Qian

    2015-06-01

    We demonstrate lensless quantitative phase microscopy and diffraction tomography based on a compact on-chip platform, using only a CMOS image sensor and a programmable color LED matrix. Based on the multi-wavelength phase retrieval and multi-angle illumination diffraction tomography, this platform offers high quality, depth resolved images with a lateral resolution of 3.72μm and an axial resolution of 5μm, across a wide field-of-view of 24mm2. We experimentally demonstrate the success of our method by imaging cheek cells, micro-beads, and fertilized eggs of Parascaris equorum. Such high-throughput and miniaturized imaging device can provide a cost-effective tool for telemedicine applications and point-of-care diagnostics in resource-limited environments.

  5. Development and testing of a homogenous multi-wavelength LED light source

    NASA Astrophysics Data System (ADS)

    Bolton, Frank J.; Bernat, Amir; Jacques, Steven L.; Levitz, David

    2017-03-01

    Multispectral imaging of human tissue is a powerful method that allows for quantify scattering and absorption parameters of the tissue and differentiate tissue types or identify pathology. This method requires imaging at multiple wavelengths and then fitting the measured data to a model based on light transport theory. Earlier, a mobile phone based multi-spectral imaging system was developed to image the uterine cervix from the colposcopy geometry, outside the patient's body at a distance of 200-300 mm. Such imaging of a distance object has inherent challenges, as bright and homogenous illumination is required. Several solutions addressing this problem were developed, with varied degrees of success. In this paper, several multi-spectral illumination setups were developed and tested for brightness and uniformity. All setups were specifically designed with low cost in mind, utilizing a printed circuit board with surface-mounted LEDs. The three setups include: LEDs illuminating the target directly, LEDs illuminating focused by a 3D printed miniature lens array, and LEDs coupled to a mixing lens and focusing optical system. In order to compare the illumination uniformity and intensity performance two experiments were performed. Test results are presented, and various tradeoffs between the three system configurations are discussed. Test results are presented, and various tradeoffs between the three system configurations are discussed.

  6. A new multi-wavelength optical-plethysmograph for quantitative determination of pulpal hemoglobin content and oxygen level using green and near-infrared LEDs

    NASA Astrophysics Data System (ADS)

    Kakino, S.; Miwa, Z.; Kirimoto, A.; Ohuchi, K.; Takatani, S.; Takagi, Y.

    2007-02-01

    A new multi-wavelength optical-plethysmograph has been designed to study the relation between the transmitted optical density (OD) of the tooth vs. hemoglobin (Hb) content and oxygen saturation (SO II) of the pulpal blood using the 467, 506, 522 and 810 nm light emitting diodes (LEDs). The experimental model utilized the extracted human upper incisor where the pulp cavity was filled with the blood having various values of Hb and SO II. A resin cap was made to fit the tooth crown and optical fibers for transmission measurement. The LEDs were pulsed sequentially at 520 Hz with the pulse duration of 240 μs. The OD as a function of Hb for the isosbestic wavelengths of 506 and 522 nm increased almost linearly from 8.0 to 11.0 for Hb changing from 0.0 (saline control) to 2.5 g/dL, but beyond 2.5 g/dL no change was observed. At 810 nm, the OD increased linearly till Hb of 13.4 g/dL, but its change was much smaller with 1.0 OD per 13.4 g/dL. As for SO II, the OD at 467 nm with Hb of 1.0 g/dL that simulated the mean pulpal Hb content in vivo varied by about 1.0 for SO II changing from 100 to 40%. The OD change with respect to Hb change at 506 and 522 nm showed better sensitivity than that at 810 nm. The combination of 467 and 506 or 522 nm wavelengths can provide a noninvasive measurement of both pulpal Hb content and SO II to diagnose pulp vitality of teeth in vivo.

  7. High precision spatial and temporal control of neural circuitry using a semi-automated multi-wavelength nanopatterning system

    NASA Astrophysics Data System (ADS)

    Mitnala, Sandhya; Huebshman, Michael; Herold, Christian; Herz, Joachim; Garner, Harold

    2009-02-01

    It has been one of the most discussed and intriguing topics -the quest to control neural circuitry as a precursor to decoding the operations of the human brain and manipulating its diseased state. Electrophysiology has created a gateway to control this circuitry with high precision. However, it is not practical to apply these techniques to living systems because these techniques are invasive and lack the spatial resolution necessary to properly address various neural cell components, cell assemblies or even tissues. Here we describe a new instrument that has the potential to replace the conventional patch clamping technique, the workhorse of neural physiology. A Digital Light Processing system from Texas Instruments and an Olympus IX71 inverted microscope were combined to achieve neuronal control at a subcellular spatial resolution. Accompanying these two technologies can be almost any light source, and for these experiments a pair of pulsed light sources that produced two pulse trains at different wavelengths tuned to activate or inactivate selectively the ChR2 and NpHR channels that were cloned to express light sensitive versions in neurons. Fura- 2 ratiometric fluorescent dye would be used to read-out calcium activity. The Pulsed light sources and a filter wheel are under computer control using a National Instruments digital control board and a CCD camera used to acquire real time cellular responses to the spatially controlled pulsed light channel activation would be controlled and synchronized using NI LabVIEW software. This will provide for a millisecond precision temporal control of neural circuitry. Thus this technology could provide researchers with an optical tool to control the neural circuitry both spatially and temporally with high precision.

  8. Multi-wavelength fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Kwong, Tiffany C.; Lo, Pei-An; Cho, Jaedu; Nouizi, Farouk; Chiang, Huihua K.; Kim, Chang-Seok; Gulsen, Gultekin

    2016-03-01

    The strong scattering and absorption of light in biological tissue makes it challenging to model the propagation of light, especially in deep tissue. This is especially true in fluorescent tomography, which aims to recover the internal fluorescence source distribution from the measured light intensities on the surface of the tissue. The inherently ill-posed and underdetermined nature of the inverse problem along with strong tissue scattering makes Fluorescence Tomography (FT) extremely challenging. Previously, multispectral detection fluorescent tomography (FT) has been shown to improve the image quality of FT by incorporating the spectral filtering of biological tissue to provide depth information to overcome the inherent absorption and scattering limitations. We investigate whether multi-wavelength fluorescent tomography can be used to distinguish the signals from multiple fluorophores with overlapping fluorescence spectrums using a unique near-infrared (NIR) swept laser. In this work, a small feasibility study was performed to see whether multi-wavelength FT can be used to detect subtle shifts in the absorption spectrum due to differences in fluorophore microenvironment.

  9. Multi-wavelength holographic profilometry

    NASA Astrophysics Data System (ADS)

    Barbosa, E. A.; Gesualdi, M. R.; Muramatsu, M.

    2006-01-01

    A novel method for surface profilometry by holography is presented. We used a diode laser emitting at many wavelengths simultaneously as the light source and a Bi 12TiO 20 (BTO) crystal as the holographic medium in single exposure processes. The employ of multi-wavelength, large free spectral range (FSR) lasers leads to holographic images covered of interference fringes corresponding to the contour lines of the studied surface. In order to obtain the relief of the studied surface, the fringe analysis was performed by the phase stepping technique (PST) and the phase unwrapping was carried out by the Cellular-automata method. We analysed the relief of a tilted flat metallic bar and a tooth prosthesis.

  10. Multi-wavelength Luminosity Functions of Galaxies

    NASA Technical Reports Server (NTRS)

    Gardner, J. P.; Miller, N. A.

    2002-01-01

    Multivariate or multi-wavelength luminosity functions will reveal the interplay between star formation, chemical evolution, and absorption and re-emission of dust within evolving galaxy populations. By using principal component analysis to reduce the dimensionality of the problem, we optimally extract the relevant photometric information from large galaxy catalogs. As a demonstration of the technique, we derive the multi-wavelength luminosity function for the galaxies in the released SDSS catalog, and compare the results with those obtained by traditional methods. This technique will be applicable to catalogs of galaxies from datasets obtained by 2MASS, and the SIRTF and GALEX missions.

  11. Multi-Wavelength Luminosity Functions of Galaxies

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2002-01-01

    Multivariate or multi-wavelength luminosity functions will reveal the interplay between star formation, chemical evolution, and ab- sorption and re-emission of dust within evolving galaxy populations. By using principal component analysis to reduce the dimensionality of the problem, I optimally extract the relevant photometric information from large galaxy catalogs. As a demonstration of the technique, I derive the multi-wavelength luminosity function for the galaxies in the released SDSS catalog, and compare the results with those obtained by traditional methods. This technique will be applicable to catalogs of galaxies from datasets obtained by 2MASS, and the SIRTF and GALEX missions.

  12. Hemodynamic and electrophysiological responses to functional activation accessed by multi-wavelength optical imaging and electrophysiological recording system

    NASA Astrophysics Data System (ADS)

    Feng, Nengyun; Liu, Yuan; Wang, Wenjia; Luo, Qingming; Li, Pengcheng

    2008-02-01

    A compact and convenient system is designed and realized for high-resolution simultaneous imaging hemodynamic parameters and recording electrophysiological signals in the brain by the combination of multi-wavelength optical imaging and electrophysiological recording system. Multi-wavelength optical imaging system uses an integration of light-emitting diode (LED which has three wavelengths) and laser diode (LD) as imaging illuminants to combine the laser speckle imaging and optical intrinsic signal imaging. Electrophysiological recording system is based on the virtual instrument technology. The spatial and temporal changes in oxy-hemoglobin, deoxy-hemoglobin, total hemoglobin concentration, cerebral blood flow, and the cerebral metabolic rate of oxygen in response to the brain activities are monitored by the multi-wavelength optical imaging system. Meanwhile the electrophysiological recording system can simultaneously collect the extra-cellular electrophysiological signals. The combination system provides the capability to simultaneously investigate hemodynamic parameters and electrophysiological signals, which may lead to a better understanding of the coupling between neuronal activation and vascular responses.

  13. Multi-Wavelength Observations of Supernova Remnants

    NASA Technical Reports Server (NTRS)

    Williams, B.

    2012-01-01

    Supernova remnants (SNRs) provide a laboratory for studying various astrophysical processes, including particle acceleration, thermal and non thermal emission processes across the spectrum, distribution of heavy elements, the physics of strong shock waves, and the progenitor systems and environments of supernovae. Long studied in radio and X-rays, the past decade has seen a dramatic increase in the detection and subsequent study of SNRs in the infrared and gamma-ray regimes. Understanding the evolution of SNRs and their interaction with the interstellar medium requires a multi-wavelength approach. I will review the various physical processes observed in SNRs and how these processes are intertwined. In particular, I will focus on X-ray and infrared observations, which probe two very different but intrinsically connected phases of the ISM: gas and dust. I will discuss results from multi-wavelength studies of several SNRs at various stages of evolution, including Kepler, RCW 86, and the Cygnus Loop.

  14. Initiation of coronal mass ejection event observed on 2010 November 3: multi-wavelength perspective

    SciTech Connect

    Mulay, Sargam; Subramanian, Srividya; Tripathi, Durgesh; Isobe, Hiroaki; Glesener, Lindsay

    2014-10-10

    One of the major unsolved problems in solar physics is that of coronal mass ejection (CME) initiation. In this paper, we have studied the initiation of a flare-associated CME that occurred on 2010 November 3 using multi-wavelength observations recorded by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and the Reuven Ramaty High Energy Solar Spectroscopic Imager. We report an observation of an inflow structure initially in the 304 Å and the 1600 Å images a few seconds later. This inflow structure was detected as one of the legs of the CME. We also observed a non-thermal compact source concurrent and near co-spatial with the brightening and movement of the inflow structure. The appearance of this compact non-thermal source, brightening, and movement of the inflow structure and the subsequent outward movement of the CME structure in the corona led us to conclude that the CME initiation was caused by magnetic reconnection.

  15. Multi-wavelength applications of gravitational lensing

    NASA Astrophysics Data System (ADS)

    Fadely, Ross

    2010-12-01

    Using an array of multi-wavelength data, we examine a variety of astrophysical problems with gravitational lensing. First, we seek to understand the mass distribution of an early-type galaxy with an analysis of the lens Q0957+561. We dissect the lens galaxy into luminous and dark components, and model the environment using results from weak lensing. Combining constraints from newly-discovered lensed images and stellar population models, we find the lens has a density profile which is shallower than isothermal, unlike those of typical early-type galaxies. Finally, using the measured time delay between the quasar images we find the Hubble constant to be H 0 = 79.3+6.7-8.5 km s-1 Mpc-1 . One intriguing application of lensing is to exploit the lens magnification boost to study high-redshift objects in greater detail than otherwise possible. Here, we analyze the mid-infrared properties of two lensed z ˜ 2 star-forming galaxies, SDSS J120602.09+514229.5 and SDSS J090122.37+181432.3, using Spitzer /IRS spectra to study their rest-frame ˜ 5-12 μm emission. Both systems exhibit strong polycyclic aromatic hydrocarbon (PAH) features in the spectra, indicating strong star formation and the absence of significant AGN activity. For SDSS J090122.37+181432.3, this detection belies that inferred from optical measurements, indicating mid-IR spectroscopy provides key information needed to understand the properties of high-redshift star-forming galaxies. While lensing provides measurements of the macroscopic properties of lens systems, it can also shed light on small-scale structure of galaxies. To identify and understand lens substructure, we examine the multi-wavelength properties of flux ratios for six lenses. Variations of the flux ratios with wavelength can be used to study the lensed quasars and the small-scale mass distribution of lens galaxies. We detect strong multi-wavelength variations in the lenses HE 0435-1223 and SDSS 0806+2006. For HE 0435-1223, we study its

  16. Automated platform for determination of LEDs spatial radiation pattern

    NASA Astrophysics Data System (ADS)

    Vladescu, Marian; Vuza, Dan Tudor

    2015-02-01

    Nowadays technologies lead to remarkable properties of the light-emitting diodes (LEDs), making them attractive for more and more applications, such as: interior and exterior lighting, outdoor LED panels, traffic signals, automotive (tail and brake lights, backlighting in dashboard and switches), backlighting of display panels, LCD displays, symbols on switches, keyboards, graphic boards and measuring scales. Usually, LEDs are small light sources consisting of a chip placed into a package, which may bring additional optics to this encapsulated ensemble, resulting in a less or more complex spatial distribution of the light intensity, with particular radiation patterns. This paper presents an automated platform designed to allow a quick and accurate determination of the spatial radiation patterns of LEDs encapsulated in various packages. Keywords: LED, luminous

  17. Multi-wavelength characterization of carbonaceous aerosol

    NASA Astrophysics Data System (ADS)

    Massabò, Dario; Caponi, Lorenzo; Chiara Bove, Maria; Piazzalunga, Andrea; Valli, Gianluigi; Vecchi, Roberta; Prati, Paolo

    2014-05-01

    Carbonaceous aerosol is a major component of the urban PM. It mainly consists of organic carbon (OC) and elemental carbon (EC) although a minor fraction of carbonate carbon could be also present. Elemental carbon is mainly found in the finer PM fractions (PM2.5 and PM1) and it is strongly light absorbing. When determined by optical methods, it is usually called black carbon (BC). The two quantities, EC and BC, even if both related to the refractory components of carbonaceous aerosols, do not exactly define the same PM component (Bond and Bergstrom, 2006; and references therein). Moreover, another fraction of light-absorbing carbon exists which is not black and it is generally called brown carbon (Andreae and Gelencsér, 2006). We introduce a simple, fully automatic, multi-wavelength and non-destructive optical system, actually a Multi-Wavelength Absorbance Analyzer, MWAA, to measure off-line the light absorption in Particulate Matter (PM) collected on filters and hence to derive the black and brown carbon content in the PM This gives the opportunity to measure in the same sample the concentration of total PM by gravimetric analysis, black and brown carbon, metals by, for instance, X Ray Fluorescence, and finally ions by Ion Chromatography. Up to 16 samples can be analyzed in sequence and in an automatic and controlled way within a few hours. The filter absorbance measured by MWAA was successfully validated both against a MAAP, Multi Angle Absorption Photometer (Petzold and Schönlinner, 2004), and the polar photometer of the University of Milan. The measurement of sample absorbance at three wavelengths gives the possibility to apportion different sources of carbonaceous PM, for instance fossil fuels and wood combustion. This can be done following the so called "aethalometer method" (Sandradewi et al., 2008;) but with some significant upgrades that will be discussed together the results of field campaigns in rural and urban sites. Andreae, M.O, and Gelencsér, A

  18. Multi-wavelength Observations of Microflares Near an Active Region

    NASA Astrophysics Data System (ADS)

    Bein, B.; Veronig, A.; Rybak, J.; Gömöry, P.; Berkebile-Stoiser, S.; Sütterlin, P.

    We study the multi-wavelength characteristics of a microflaring active region (AR 10898) near disc centre. The analysed data were from the 4^{th} of July 2006, and were recorded by DOT (Hα, Ca II H), RHESSI (X-rays), TRACE (EUV) and SOHO/MDI (magnetograms). The identified microflare events were studied with respect to their magnetic field configuration and their multi-wavelength time evolution.

  19. Virtual Sky Surveys and Multi-wavelength Investigations of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Nord, Brian D.

    2010-12-01

    The advent of large and overlapping sky surveys brings promise of a new era in the study of galaxy clusters and dark energy. Clusters have been used for decades as faithful buoys of space-time, tracing cosmic evolution through their matter content and spatial distribution. High-fidelity tracking relies on a robust connection between observable cluster signatures and the underlying dark matter content, which is otherwise invisible. Until now, clusters have been mostly viewed through independent signals in distinct wavebands. The next era of cluster cosmology may be led by multi-variate, cross-waveband detections and analyses of clusters, where different facets of clusters can be cross-correlated to develop a more complete, unified picture of cluster populations. To these ends, in this dissertation, I perform multi-variate analyses of galaxy cluster populations and develop a simulated sky survey, with which to prepare for the next generation of multi-wavelength cluster observations. First, in a new multi-variate framework, I quantify the effects of observational biases on measures of the cluster distribution function and on cosmological constraints derived from X-ray cluster populations. I also demonstrate the indispensability of the multi-variate approach in measuring the evolution of X-ray galaxy clusters; without it, we find that the combination of scatter, intrinsic correlation and irrevocable survey flux limits substantially confuses any measure of redshift evolution. Next, I construct the Millennium Gas Simulation-Virtual Sky Survey (MGSVSS), a multi-wavelength mock sky derived from an N-body gas-dynamic simulation. The MGSVSS contains both sub-mm and optical wavelength sky signals to redshift, z = 1., in a 5 x 5deg2 field of view, with O (103) halos, O (104) optically selected clusters, and O (102) clusters selected via the Sunyaev-Zel'dovich (SZ) signature. The SZ sky also includes a minimal level of sky and instrumental noise, which nearly mimics that of

  20. Switchable multi-wavelength fiber ring laser using a side-leakage photonic crystal fiber based filter

    NASA Astrophysics Data System (ADS)

    Chen, Weiguo; Lou, Shuqin; Wang, Liwen; Zou, Hui; Lu, Wenliang; Jian, Shuisheng

    2012-04-01

    A switchable multi-wavelength fiber ring laser is proposed and experimentally demonstrated with a novel side-leakage photonic crystal fiber (SLPCF) based filter incorporated into the ring cavity at room temperature. Stable multi-wavelength laser operations can be achieved due to the spatial mode beating, polarization hole burning and spectral hole burning effects. By adjusting the polarization controller appropriately, the laser can be switched among the single-, dual- and triple-wavelength lasing oscillations whose signal-to-noise ratio is up to 50 dB. In addition, the lasing wavelength can be also tuned and switched by applying the strain to the filter.

  1. System and Method for Multi-Wavelength Optical Signal Detection

    NASA Technical Reports Server (NTRS)

    McGlone, Thomas D. (Inventor)

    2017-01-01

    The system and method for multi-wavelength optical signal detection enables the detection of optical signal levels significantly below those processed at the discrete circuit level by the use of mixed-signal processing methods implemented with integrated circuit technologies. The present invention is configured to detect and process small signals, which enables the reduction of the optical power required to stimulate detection networks, and lowers the required laser power to make specific measurements. The present invention provides an adaptation of active pixel networks combined with mixed-signal processing methods to provide an integer representation of the received signal as an output. The present invention also provides multi-wavelength laser detection circuits for use in various systems, such as a differential absorption light detection and ranging system.

  2. Identification of aerosol composition from multi-wavelength lidar measurements

    NASA Technical Reports Server (NTRS)

    Wood, S. A.

    1984-01-01

    This paper seeks to develop the potential of lidar for the identification of the chemical composition of atmospheric aerosols. Available numerical computations suggest that aerosols can be identified by the wavelength dependence of aerosol optical properties. Since lidar can derive the volume backscatter coefficient as a function of wavelength, a multi-wavelength lidar system may be able to provide valuable information on the composition of aerosols. This research theoretically investigates the volume backscatter coefficients for the aerosol classes, sea-salts, and sulfates, as a function of wavelength. The results show that these aerosol compositions can be characterized and identified by their backscatter wavelength dependence. A method to utilize multi-wavelength lidar measurements to discriminate between compositionally different thin aerosol layers is discussed.

  3. Multi-Wavelength Studies of Low Redshift Clusters: Lessons Learned

    NASA Astrophysics Data System (ADS)

    Donahue, Megan

    2017-07-01

    I describe some of the insights about how AGN feedback works to regulate the gas supply for star formation and AGN activity achieved from multi-wavelength observations of (relatively) low redshift clusters of galaxies. The examples are mostly drawn from my group's work on Brightest Cluster Galaxies and their relation to the thermodynamic state of the hot intracluster gas in the core of their host clusters of galaxies.

  4. Oscillation signature from multi-wavelength analysis on solar chromosphere

    SciTech Connect

    Mumpuni, Emanuel Sungging; Herdiwijaya, Dhani; Djamal, Mitra

    2014-03-24

    In this work, we investigate how the solar chromosphere responds to the photospheric dynamics by using tomography study, implementing multiwavelength analysis observations obtained from Dutch Open Telescope. By using high resolution, high-quality, simultaneous image sequences of multi-wavelength data, we try to obtain the oscillation signature that might play important role on chromospheric dynamic by using H-alpha (Hα) as primary diagnostic tool.

  5. Swift Multi-wavelength Observing Campaigns: Strategies and Outcomes

    NASA Technical Reports Server (NTRS)

    Krimm, Hans A.

    2007-01-01

    The Swift gamma-ray burst explorer has been operating since December 2004 as both a gamma-ray burst (GRB) monitor and telescope and a multi-wavelength observatory, covering the energy range from V band and near UV to hard X rays above 150 keV. It is designed to rapidly repoint to observe newly discovered GRBs, and this maneuverability, combined with an easily changed observing program, allows Swift to also be an effective multiwavelength observatory for non-GRB targets, both as targets of opportunity and pre-planned multi-wavelength observing campaigns. Blazars are particularly attractive targets for coordinated campaigns with TeV experiments since many blazars are bright in both the hard X-ray and TeV energy ranges. Successful coordinated campaigns have included observations of 3C454.3 during its 2005 outburst. The latest Swift funding cycles allow for non- GRB related observations to be proposed. The Burst Alert Telescope on Swift also serves as a hard X-ray monitor with a public web page that includes light curves for over 400 X-ray sources and is used to alert the astronomical community about increased activity from both known and newly discovered sources. This presentation mill include Swift capabilities, strategies and policies for coordinated multi-wavelength observations as well as discussion of the potential outcomes of such campaigns.

  6. Multi-Wavelength and Nonlinear Quantum Cascade Lasers

    NASA Astrophysics Data System (ADS)

    Gmachl, Claire

    2006-03-01

    Quantum Cascade (QC) lasers are a rapidly evolving mid-infrared technology well suited for chemical sensing applications. For sensing of trace gas mixtures, large molecules, or liquids, probing at a single wavelength is often not sufficient, but the analyte must be sampled at various wavelengths. Here, we will discuss various means of providing multi-wavelength emission from QC lasers. Four different routes are currently being investigated. First, the active waveguide core of a QC laser can be subdivided into substacks of different active regions, hence allowing for multi-wavelength emission. We will discuss the design optimization procedures employed to develop a multi-wavelength laser module with several wavelengths covering the 7 -- 13 μm wavelength range. Second, QC lasers can be designed to emit different wavelength light when operated at different (positive or negative) bias settings. We have recently developed such a QC laser capable of emitting at ˜ 8 and ˜ 11 μm. Third, nonlinear QC lasers that in addition to QC laser active regions also include nonlinear mixing regions emit light not only at the fundamental frequency, but also at nonlinear frequencies. Second harmonic generation with up to 2 mW of nonlinear light has recently been demonstrated. Finally, QC lasers with very broad gain spectra can in principle be used to tune over significant wavelength ranges using an external cavity. A key component for such tunability is a low reflectance laser facet to suppress laser action based on feedback from the laser facets. We will show approaches to facet reflection reduction through sub-wavelength facet patterning. This work is supported through collaboration with Pacific Northwest National Labs / Battelle by DARPA L-PAS, the DOE, and the NSF ECS-0400615. This work is being conducted in collaboration with A. Dirisu, S.S. Howard, Z. Liu, O. Malis, G. Shu, D.L. Sivco, and F. Toor.

  7. Molecular transport network security using multi-wavelength optical spins.

    PubMed

    Tunsiri, Surachai; Thammawongsa, Nopparat; Mitatha, Somsak; Yupapin, Preecha P

    2016-01-01

    Multi-wavelength generation system using an optical spin within the modified add-drop optical filter known as a PANDA ring resonator for molecular transport network security is proposed. By using the dark-bright soliton pair control, the optical capsules can be constructed and applied to securely transport the trapped molecules within the network. The advantage is that the dark and bright soliton pair (components) can securely propagate for long distance without electromagnetic interference. In operation, the optical intensity from PANDA ring resonator is fed into gold nano-antenna, where the surface plasmon oscillation between soliton pair and metallic waveguide is established.

  8. Multi-wavelength Accretion Studies of Cataclysmic Variable Stars

    NASA Astrophysics Data System (ADS)

    Coppejans, Deanne

    2016-10-01

    Recent developments in the field of Cataclysmic Variable stars (CVs) have highlighted the need for large (more unbiased) samples of CVs with known properties, as well as the need for multi- wavelength studies to determine the accretion-outflow connection. In this thesis I have presented radio observations of non-magnetic CVs, proving them to be significant radio emitters. I have also presented optical follow-up studies of CVs, and developed an algorithm that automatically classifies these objects based on photometric data from large surveys. This was applied to the Catalina Real-time Transient Survey to produce a catalogue of accretion properties for 1031 CVs.

  9. Characteristics of a cascaded grating multi wavelength dye laser

    NASA Astrophysics Data System (ADS)

    Rana, Paramjit; Sridhar, G.; Manohar, K. G.

    2016-12-01

    Characteristics of a multi wavelength dye laser in two cascaded grating resonator configurations are presented. DCM dye dissolved in ethanol, was transversely pumped by second harmonic of Nd:YAG laser and four wavelength, independently tunable, collinear dye laser operation was obtained in Cascaded Grazing Incidence Grating cavity (CGIG) and Hybrid CGIG with fourth grating in Littrow angle (HCGIG) configuration. Gain competition effect of all the sub-cavities was fully characterized and wavelength zones of operation were identified for each cavity for sustaining four wavelength operation. Overall efficiency of the oscillator was measured to be around 2% in CGIG and 7% in HCGIG.

  10. Multi-Wavelength Observations of Nearby Starburst Galaxies

    NASA Astrophysics Data System (ADS)

    Johnson, Kelsey; Lee, Janice

    Do cycles of violent, intense, but short-lived bursts constitute a significant mode of global starformation in present-day galaxies? Such events can have a profound effect on galaxies, particularly those with shallowpotential wells, and observational measures of their prevalence inform our understanding of a wide range of issues ingalaxy evolution. I will highlight what we have learned about starbursts from multi-wavelength observations of galaxiesin the local volume on both galactic and smaller scales, and explore how connections with the study of the deaths ofmassive stars may further our understanding of open issues in galaxy evolution.

  11. Multi-Wavelength Observations of Nearby Starburst Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Janice

    2015-08-01

    Do cycles of violent, intense, but short-lived bursts constitute a significant mode of global star formation in present-day galaxies? Such events can have a profound effect on galaxies, particularly those with shallow potential wells, and observational measures of their prevalence inform our understanding of a wide range of issues in galaxy evolution. I will highlight what we have learned about starbursts from multi-wavelength observations of galaxies in the local volume on both galactic and smaller scales, and explore how connections with the study of the deaths of massive stars may further our understanding of open issues in galaxy evolution.

  12. Multi-wavelength multi-level optical storage

    NASA Astrophysics Data System (ADS)

    Wullert, John R., II

    Current digital information storage technologies offer rapid access and seemingly ever-increasing capacities. New storage techniques that improve the data rate of high-density storage technologies are attractive, particularly for cost-sensitive services such as video on demand. Wavelength multiplexing of optical information storage has the potential to increase storage capacity, density and data rate. This dissertation addresses the design, simulation and fabrication of a multi-wavelength, multi-level optical storage structure that has the potential to increase the capacity, density and data rate of optical storage. Multi-wavelength, multi-layer optical storage is a technique for storing data in many separate layers in a medium, where each layer responds to a unique optical wavelength. This approach builds on the strengths of current optical storage technologies and addresses some of their limitations. Multiple layers of storage increase the high storage density possible with optical techniques and the parallelism of wavelength multiplexing improves the relatively low data rate. Multi-wavelength, multi-level optical storage has been investigated theoretically and experimentally. The experimental results provide the first demonstration of optical storage using three wavelengths to read three separate layers of information. These read-only optical memories were based on dielectric mirrors of silicon dioxide, magnesium oxide and aluminum oxide. The layers were designed to be read with semiconductor lasers of 635, 780 and 980 nanometers. The prototype devices exhibited open margins between the on and off states for all eight combinations of the presence and absence of the three mirrors. Theoretical simulations were employed to assess the dynamic operation of multi-wavelength storage devices. Through systematic simulations, variations in the thickness and refractive index of the layers in the structure were identified as the primary noise mechanism and a critical

  13. Multi-wavelength optical storage of diarylethene PMMA film

    NASA Astrophysics Data System (ADS)

    Guo, Haobo; Zhang, Fushi; Wu, Guo-shi; Sun, Fan; Pu, Shouzhi; Mai, Xuesong; Qi, Guosheng

    2003-05-01

    Current commercial optical storage technologies are all based on the heat effect of the recording laser, i.e., heat-mode optical storage. In the present work, photon-mode optical storage using photochromic diarylethene materials was investigated. Two diarylethene derivatives were dispersed into PMMA solution, and spin-coated on a glass substrate with Al reflective layer as the recording layer. Two laser beams of 532 and 650 nm were used in recording and readout simultaneously, and signals with high S/ N ratio were detected. Multi-wavelength optical storage was realized with the diarylethene PMMA film.

  14. Explaining Multi-wavelength Photometric Variability in Young Stellar Objects

    NASA Astrophysics Data System (ADS)

    Kesseli, Aurora; Whitney, B.; Wood, K.; Plavchan, P.; Terebey, S.; Stauffer, J. R.; Morales-Calderon, M.; YSOVAR

    2013-01-01

    We explore a variety of radiation transfer models to explain multi-wavelength photometric variability of young stellar objects in the Orion Nebula Cluster (Morales-Calderon et al. (2011). Our models include hotspots, warps in the accretion disk, and spiral arms. Variability comes in different types, which have been categorized as periodic or quasi-periodic, narrow or broad dips in the light curves, and rapid flux variations or “wild type” stars. Our models can successfully reproduce these. The optical and near-infrared light curves are sensitive to the stellar variations and obscurations from the circumstellar material. The mid-infrared provides an additional diagnostic because it is sensitive to emission from the inner disk and the inner wall height. Our models make specific predictions as to the shapes and phasing of optical through mid-infrared photometry that can be tested with multi-wavelength time-series data. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech and was partially supported by the National Science Foundation's REU program through NSF Award AST-1004881.

  15. Multi-wavelength photoplethysmography method for skin arterial pulse extraction

    PubMed Central

    Liu, Jing; Yan, Bryan Ping-Yen; Dai, Wen-Xuan; Ding, Xiao-Rong; Zhang, Yuan-Ting; Zhao, Ni

    2016-01-01

    In this work, we present a multi-wavelength (MW) PPG method exploiting the wavelength dependence of light penetration in skin tissue to provide depth resolution of skin blood pulsation. The MW PPG system requires two to three light sources in different wavelengths and extracts the arterial blood pulsation through a multi-wavelength multi-layer light-skin interaction model, which removes the capillary pulsation (determined from the short-wavelength PPG signal) from the long-wavelength PPG signal using absorption weighting factors that are quasi-analytically calibrated. The extracted pulsations are used to calculate blood pressure (BP) through pulse transit time (PTT), and the results are compared with those obtained from the single wavelength PPG method. The comparative study is clinically performed on 20 subjects including 10 patients diagnosed with cardiovascular diseases and 10 healthy subjects. The result demonstrates that the MW PPG method significantly improves the measurement accuracy of systolic BP (SBP), reducing the mean absolute difference between the reference and the estimated SBP values from 5.7 mmHg (for single-wavelength PPG) to 2.9 mmHg (for three-wavelength PPG). PMID:27867733

  16. Multi-wavelength fluorometry for anaerobic digestion process monitoring.

    PubMed

    Morel, E; Santamaria, K; Perrier, M; Guiot, S R; Tartakovsky, B

    2005-01-01

    Applicability of multi-wavelength fluorometry for anaerobic digestion process monitoring was investigated in a 3.5 L upflow anaerobic sludge bed (UASB) lab-scale reactor. Both off-line and on-line monitoring of key process parameters was tested. Off-line emission spectra were measured at an angle of 90 degrees to the excitation beam using a cuvette. On-line measurements were carried out using a fiber optic probe in the external recirculation line of the digester. Fluorescence spectra were correlated to available analytical measurements to obtain partial least square regression models. An independent set of measurements was used to validate the regression models. Model estimations showed reasonable agreement with analytical measurements with multiple determination coefficients (R2) between 0.6 and 0.95. Results showed that offline fluorescence measurements can be used for fast estimation of anaerobic digestor effluent quality. At the same time, the on-line implementation of multi-wavelength fluorescence measurements can be used for realtime process monitoring and, potentially, for on-line process control.

  17. Multi-wavelength coverage of outburst decays of LMXBs

    NASA Astrophysics Data System (ADS)

    Kalemci, Emrah; Tomsick, John; Bailyn, Charles; Dincer, Tolga

    2016-07-01

    Low mass X-ray binaries (LMXB) are dynamic laboratories that are powered by accretion, and under some conditions these systems create strong outflows in the form of highly collimated jets, or winds. Outburst decays of transient LMXBs provide additional information about compact jets and their relation to changes in timing properties. Our group characterizes the multi-wavelength evolution of Galactic black hole transients during their outburst decays using simultaneous X-ray (RXTE, Swift, and INTEGRAL), optical/infrared (SMARTS) and radio (VLA, ATCA, VLBI). By characterizing the X-ray spectral and timing evolution of these systems, and merging this information with the evolution in the near-infrared and radio, we obtain the conditions necessary to launch stable compact jets, and discuss how jets can be influencing and/or influenced by X-ray timing and spectral properties of these systems. In this presentation, I will summarize recent results regarding multi-wavelength observations of not only black hole systems, but also neutron star X-ray binaries during outburst decays, and discuss models that explain not only the broad spectral energy distribution, but also some of the timing properties of these systems.

  18. Spectral spatial coherence of high-power multi-chip LEDs

    NASA Astrophysics Data System (ADS)

    Chen, Guang-ming; Tao, Hua; Lin, Hui-chuan; Chen, Zi-yang; Pu, Ji-xiong

    2012-11-01

    We investigate the spatial coherence of the light generated from high-power multi-chip red LEDs by using the van Cittert-Zernike theorem. It is theoretically demonstrated that the light generated from multi-chip LEDs evolves into partially coherent light after propagation, and the spatial coherence is increased with the increase of propagation distance. Moreover, the spatial coherence of the light is found to be closely related to the chip distribution of multi-chip LEDs. The distribution of the spatial coherence of the light is experimentally examined by Young's double-slit interference. It is found that the experimental results are consistent with the theoretical ones.

  19. Multi-wavelength polarimetry: a powerful tool to study the physics of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Goosmann, R. W.

    2009-11-01

    Accreting supermassive black holes reside in a very complex environment and the inner structure and dynamics of active galactic nuclei (AGN) are not well understood yet. In this note, I point out the important role that multi-wavelength polarimetry can play in understanding AGN. In addition to spectroscopy, the measurement of the polarization percentage and position angle provides two more observables that are sensitive to the geometry and kinematics of emission and scattering regions. Furthermore, time-dependent polarimetry allows to measure spatial distances between emission regions and scattering mirrors by applying a reverberation technique. For radiation coming from the direct vicinity of the black hole, the polarization also contains information about the space-time metric. Spectropolarimetry observations of AGN are obtained in the radio, the infrared, the optical, and the ultraviolet wave bands and in the future they are going be available also in the X-ray range. To interpret these observations in a coherent way, it is necessary to study models that do not only reproduce the broad-band spectroscopy properties of AGN but also their multi-wavelength polarization signature. I present a first step towards such models for the case of radio-quiet AGN. The modeling reveals the optical/UV and X-ray polarization properties of the reprocessed radiation coming from the obscuring torus. The discussion about the implications of such models includes prospects for the up-coming technique of X-ray (spectro-)polarimetry.

  20. Fast time-lens-based line-scan single-pixel camera with multi-wavelength source

    PubMed Central

    Guo, Qiang; Chen, Hongwei; Weng, Zhiliang; Chen, Minghua; Yang, Sigang; Xie, Shizhong

    2015-01-01

    A fast time-lens-based line-scan single-pixel camera with multi-wavelength source is proposed and experimentally demonstrated in this paper. A multi-wavelength laser instead of a mode-locked laser is used as the optical source. With a diffraction grating and dispersion compensating fibers, the spatial information of an object is converted into temporal waveforms which are then randomly encoded, temporally compressed and captured by a single-pixel photodetector. Two algorithms (the dictionary learning algorithm and the discrete cosine transform-based algorithm) for image reconstruction are employed, respectively. Results show that the dictionary learning algorithm has greater capability to reduce the number of compressive measurements than the DCT-based algorithm. The effective imaging frame rate increases from 200 kHz to 1 MHz, which shows a significant improvement in imaging speed over conventional single-pixel cameras. PMID:26417527

  1. Performance enhancement of multi-wavelength generations based on SOAs with a microfiber Mach-Zehnder interferometer

    NASA Astrophysics Data System (ADS)

    Kharraz, Osayd M.; Mohammad, Abu Bakar B.; Ahmad, Harith; Jasim, Ali A.

    2017-07-01

    Functionality improvement of a non-linear semiconductor optical amplifier for multi-wavelength generation is reported. A microfiber Mach-Zehnder interferometer (MMZI) is incorporated to enhance the multi-wavelength generation performance in terms of optical signal-to-noise ratio (OSNR) and full-width-half-maximum linewidth. The proposed scheme offers better dynamic functionality, with flexible tunable and switchable properties. Incorporating the MMZI causes spatial mode beating interference, resulting in narrow bands and power-efficient modes. Tunable and switchable octuple wavelength is demonstrated using non-linear polarization rotation (NPR), with frequency separation with respect to the free spectral range of the implemented MMZI over a greater than 30 nm span. The NPR effect is induced to suppress mode competition within the homogeneous broadening linewidth of the employed semiconductor optical amplifier.

  2. Multi-wavelength Observation of Recurrent Circular-Ribbon Flares

    NASA Astrophysics Data System (ADS)

    Zhu, Chunming; Yang, Kai; Qiu, Jiong; Takeda, Aki; Yoshimura, Keiji

    2017-08-01

    Circular ribbon flare suggests the existence of a particular fan-spine magnetic topology in the solar corona. Here we present a multi-wavelength study of recurrent circular-ribbon flares in AR 12242 during 7 days when it passes across the solar disk. As the central parasitic polarities continuously emerge through the solar surface, the circular ribbons grow correspondingly. The evolution of the overall 3D magnetic configurations is studied with potential-field extrapolations. Following the expansion of the fan surface, the heights of the null point tend to increase and then decrease, while the length of the spine tends to shrink. We discuss the evolution of the fan-spine structure and its implications for varying flare emissions in different wavelengths.

  3. Multi-wavelength VCSEL arrays using high-contrast gratings

    NASA Astrophysics Data System (ADS)

    Haglund, Erik; Gustavsson, Johan S.; Sorin, Wayne V.; Bengtsson, Jörgen; Fattal, David; Haglund, Àsa; Tan, Michael; Larsson, Anders

    2017-02-01

    The use of a high-contrast grating (HCG) as the top mirror in a vertical-cavity surface-emitting laser (VCSEL) allows for setting the resonance wavelength by the grating parameters in a post-epitaxial growth fabrication process. Using this technique, we demonstrate electrically driven multi-wavelength VCSEL arrays at 980 nm wavelength. The VCSELs are GaAs-based and the suspended GaAs HCGs were fabricated using electron-beam lithography, dry etching and selective removal of an InGaP sacrificial layer. The air-coupled cavity design enabled 4-channel arrays with 5 nm wavelength spacing and sub-mA threshold currents thanks to the high HCG reflectance.

  4. Multi-wavelength probes of distant lensed galaxies

    NASA Astrophysics Data System (ADS)

    Serjeant, Stephen

    2012-08-01

    I summarise recent results on multi-wavelength properties of distant lensed galaxies, with a particular focus on Herschel. Submm surveys have already resulted in a breakthrough discovery of an extremely efficient selection technique for strong gravitational lenses. Benefitting from the gravitational magnification boost, blind mm-wave redshifts have been demonstrated on IRAM, SMA and GBT, and follow-up emission line detections have been made of water, [Oiii], [Cii] and other species, revealing the PDR/XDR/CRDR conditions. I also discuss HST imaging of submm lenses, lensed galaxy reconstruction, the prospects for ALMA and e-Merlin and the effects of differential magnification. Many emission line diagnostics are relatively unaffected by differential magnification, but SED-based estimates of bolometric fractions in lensed infrared galaxies are so unreliable as to be useless, unless a lens mass model is available to correct for differential amplification.

  5. Multi-wavelength Observations of Cygnus X-3

    NASA Astrophysics Data System (ADS)

    Varlotta, Angelo; VERITAS

    2011-09-01

    Cygnus X-3 is a X-ray binary system containing a stellar-mass black hole and a Wolf-Rayet companion star with prominent jets, placing it in the sub-category of microquasars. Due to their similarities with AGN and GRBs, they are thought to be possible gamma-ray emitters, as the recent Fermi LAT detection has proven. We have carried out VERITAS observations on this source to find a link between the hard X-ray, GeV gamma-ray and TeV gamma-ray emissions. These observations have been triggered on the recent AGILE and Swift ATels, respectively ATel #3386 and ATel #3439. This result aims to shed light on the mechanisms of particle acceleration and gamma-ray emission in microquasars within the high-energy multi-wavelength context.

  6. Multi-Wavelength Monitoring of GRS 1915+105

    NASA Technical Reports Server (NTRS)

    Bandyopadhyay, R.; Martini, P.; Gerard, E.; Charles, P. A.; Wagner, R. M.; Shrader, C.; Shahbaz, T.; Mirabel, I. F.

    1997-01-01

    Since its discovery in 1992, the superluminal X-ray transient GRS 1915+105 has been extensively observed in an attempt to understand its behaviour. We present here first results from a multi-wavelength campaign undertaken from July to September 1996. This study includes X-ray data from the RXTE All Sky Monitor and BATSE, two-frequency data from the Nancay radio telescope, and infrared photometry from the 1.8 m Perkins telescope at Lowell Observatory. The first long-term well-sampled IR light curve of GRS 1915+105 is presented herein and is consistent with the interpretation of this source as a long-period binary. We compare the various light curves, searching for correlations in the behaviour of the source at differing wavelengths and for possible periodicities.

  7. Advances from Recent Multi-wavelength Campaigns on Sgr A*

    NASA Astrophysics Data System (ADS)

    Haggard, Daryl

    2017-01-01

    Sagittarius A* is the closest example of a supermassive black hole and our proximity allows us to detect emission from its accretion flow in the radio, submillimeter, near IR, and X-ray regimes. Ambitious monitoring campaigns have yielded rich multi-wavelength, time-resolved data that have the power to probe the physical processes underlying Sgr A*'s quiescent and flare emission. Here, I review the status of Sgr A* X-ray monitoring campaigns from the Chandra X-ray Observatory (also XMM Newton, and Swift), and efforts to coordinate these with observations across the electromagnetic spectrum. I also discuss how these observations constrain models for Sgr A*'s variability, which range from tidal disruption of asteroids to gravitational lensing to collimated outflows to magnetic reconnection.

  8. Multi-Wavelength Monitoring of GRS 1915+105

    NASA Technical Reports Server (NTRS)

    Bandyopadhyay, R.; Martini, P.; Gerard, E.; Charles, P. A.; Wagner, R. M.; Shrader, C.; Shahbaz, T.; Mirabel, I. F.

    1997-01-01

    Since its discovery in 1992, the superluminal X-ray transient GRS 1915+105 has been extensively observed in an attempt to understand its behaviour. We present here preliminary results from a multi-wavelength campaign undertaken from July to September 1996. This study includes X-ray data from the RXTE All Sky Monitor and BATSE, two-frequency data from the Nancay radio telescope, and infrared photometry from the 1.8m Perkins telescope at Lowell Observatory. The K-band data presented herein provide the first long-term well-sampled IR light curve of GRS 1915+105. We compare the various light curves, searching for correlations in the behaviour of the source at differing wavelengths and for possible periodicities.

  9. Preselecting AGN candidates from multi-wavelength data by ADTree

    NASA Astrophysics Data System (ADS)

    Zhang, Yanxia; Zheng, Hongwen; Zhao, Yongheng

    2005-03-01

    With the information era in astronomy coming, this "data avalanche" may provide many answers to important problems in contemporary astrophysics. The most important problem is sifting through massive amounts of data to mine knowledge. In this paper, we positionally cross-identify multi-wavelength data from optical, near-infrared, and x-ray bands, and then employ alternating decision trees (adtree) to quickly and robustly separate AGN candidates to a high degree of accuracy. We emphasise the application of the method due to the development of large survey projects and the establishment of the virtual observatory, and conclude that the application of data mining algorithms in astronomy is of great importance to discover new knowledge impossible to obtain before, and promote the development of astronomy.

  10. Rules of Emissivity Sample Choice in Multi-wavelength Pyrometry

    NASA Astrophysics Data System (ADS)

    Liang, M.; Sun, B.; Sun, X.; Xie, J.; Yu, C.

    2017-03-01

    Since the theory for emissivity sample (example) is not clear, there exists unavoidable blindness in the sample choice for the true temperature determination (create emissivity samples using an assumption to calculate the true temperature according to brightness temperature and wavelength) in multi-wavelength pyrometry, resulting in considerable computational complexity and slow computing speed. In this article, the rules of the emissivity sample were first discovered through the theoretical analysis of the relationship between brightness temperature and emissivity, which provide a theoretical basis for the emissivity sample choice. Furthermore, the rules can reduce the sample size (amount) and improve the calculation speed. The effectiveness of the proposed rules was verified by measuring the true temperature of a solid rocket engine plume, in which the rules were applied to effectively select emissivity samples. The experimental results demonstrate that the computing speed of the true temperature determination can be improved by 5.73% to 48.64%.

  11. The Spectropyrometer—a Practical Multi-wavelength Pyrometer

    NASA Astrophysics Data System (ADS)

    Felice, Ralph A.

    2003-09-01

    An expert-system multi-wavelength pyrometer, commercially available since 1997 and using a spectrophotometer as its detector, has been able to overcome many well-known difficulties of pyrometry, including unknown, changing, and/or spectral dependence of emissivity as well as environmental absorption of radiation. In addition to a spectrophotometer and the usual optics, the instrument includes a computer which analyzes each measurement and then returns the temperature, the tolerance (a real-time measure of accuracy), and the signal strength (a quantity directly related to the emissivity at a chosen wavelength). The computer allows the input data, namely the thermal spectrum for each temperature measurement, to be saved. Accuracy to 0.10 % is routinely achieved.

  12. Multi-wavelength analysis of Ellerman Bomb Light Curves

    NASA Astrophysics Data System (ADS)

    Herlender, M.; Berlicki, A.

    We present the results of a multi-wavelength photometric analysis of Ellerman Bomb (EB) observations obtained from the Dutch Open Telescope. In our data we have found 6 EBs located in the super-penumbra of the main spot in the active region NOAA 10781. We present light curves of EB observed in the Hα line centre and wing +0.7 Å, in the Ca II H line centre and wing~+2.35 Å, in the G-band and in the TRACE 1600 Å filter. We have shown that EBs were visible in the G-band and moreover, there was a good correlation between the light curves in the G-band and in the Hα line wings. We also found quasi-periodic oscillations of EBs brightness in the G-band, CaII H line and TRACE 1600 Å filter.

  13. Fast multi-wavelength variability from a black hole

    NASA Astrophysics Data System (ADS)

    O'Brien, Kieran

    2011-10-01

    Correlated fast multi-wavelength variability is quickly becoming a key tool for studying the physics of accretion and ejection of relativistic jets. Using simultaneous X-ray and near-infrared data we have recently discovered vibrations from a relativistic jet down to 62.5 ms time scale, which allowed us to estimate the speed and the size of the jet. We have also shown that the properties of the jet depend on the spectral state of the black hole. We propose to monitor the outburst evolution of a black hole transient with XMM, simultaneously with ground-based optical and infrared facilities, in order to apply the same technique to different spectral states. We propose to perform 10 short XMM observations (7 ks each) of an active black hole, in order to cover the different stages of the outburst.

  14. Multi-wavelength analysis from tomography study on solar chromosphere

    SciTech Connect

    Mumpuni, Emanuel Sungging; Herdiwijaya, Dhani; Djamal, Mitra

    2015-04-16

    The Sun as the most important star for scientific laboratory in astrophysics as well as encompassing all living aspect on Earth, still holds scientific mystery. As the established model that the Sun’s energy fueled by the nuclear reaction, along with transport process to the typical Solar surface on around 6000-K temperature, many aspects still left as an open questions, such as how the chromosphere responded to the photospheric dynamics. In this preliminary work, we try to analyze the Solar chromosphere respond to the Photospheric dynamics using tomography study implementing multi-wavelength analysis observation obtained from Dutch Open Telescope. Using the Hydrogen-alpha Doppler signal as the primary diagnostic tool, we try to investigate the inter-relation between the magnetic and gas pressure dynamics that occur in the chromosphere.

  15. Multi-wavelength study of MGRO J2019+37

    NASA Astrophysics Data System (ADS)

    Hou, Chao; Chen, Song-Zhan; Yuan, Qiang; Cao, Zhen; He, Hui-Hai; Sheng, Xiang-Dong

    2014-08-01

    MGRO J2019+37, within the Cygnus region, is a bright extended source revealed by Milagro at 12-35 TeV. This source is almost as bright as the Crab Nebula in the northern sky, but is not confirmed by ARGO-YBJ around the TeV scale. Up to now, no obvious counterpart at low energy wavelengths has been found. Hence, MGRO J2019+37 is a rather mysterious object and its VHE γ-ray emission mechanism is worth investigating. In this paper, a brief summary of the multi-wavelength observations from radio to γ-rays is presented. All the available data from XMM-Newton and INTEGRAL at X-ray, and Fermi-LAT at γ-ray bands, are used to get constraints on its emission flux at low energy wavelengths. Then, its possible counterparts and the VHE emission mechanism are discussed.

  16. Towards a multi-wavelength spectroscopy platform for blood characterization and analysis.

    PubMed

    Kisomi, Alireza Avakh; Landari, Hamza; Boukadoum, Mounir; Miled, Amine; Gosselin, Benoit

    2016-08-01

    Passing multiple light wavelengths through a blood sample makes it possible to investigate the presence and composition of cells, metabolytes and analytes such as blood cells, glucose, lactate and oxygen, providing valuable indications for diagnostic and health monitoring. In this paper, we present a test prototype of a multi-wavelength blood spectroscopy platform integrated with a microfluidic substrate to collect and convey blood samples through a series of micro-LEDs and a photo-detector. This spectroscopy platform is a proof of concept for a system that can collect absorbance and transmittance parameters of blood samples at several wavelengths within the visible and NIR spectrum, and transmit them wirelessly to a base station for real-time calculation and analysis. In-vitro measurements are performed with the proposed prototype with 5 channels covering wavelength from 400 nm to 940 nm A full characterization results of the proposed device are presented.

  17. Understanding Grb Physics With Multi-Wavelength Data

    NASA Astrophysics Data System (ADS)

    Zhang, Bing

    The study of Gamma-ray bursts (GRBs) has entered a full multi-wavelength era. A rich trove of data from NASA GRB missions and ground-based follow up observations have been collected. Careful data mining with well-defined scientific objectives holds the key to address open questions in GRB physics, such as jet composition, radiation mechanism, progenitor and central engine physics. We propose to perform data analyses in the following three directions. 1. The time resolved GRB spectra have a dominant component that can be fit with a phenomenological ``Band'' function. The physical meaning of this function remains unclear. Recently we made a breakthrough in theoretical modeling, and showed that fast-cooling synchrotron radiation of electrons in a decreasing magnetic field can mimic the Band function in detector's bandpass, but differs from Band function slightly. We propose to apply this physically-motivated model to systematically fit the GRB prompt emission data collected by Fermi GBM and LAT, and test whether the dominant GRB emission mechanism is fast cooling synchrotron radiation. We will also fit time-dependent spectra with a time-dependent model to investigate whether a quasi- thermal "photosphere'' emission component is indeed needed to fit the observed spectra. This would shed light onto the unknown composition of GRB jets. By fitting the time resolved spectra, we will also constrain important physical parameters of GRB prompt emission, such as the emission site of GRBs, the strength of magnetic fields, as well as their evolution with radius. 2. Recent GRB multi-wavelength observations suggest that it is not straightforward to define the physical category of a GRB based on the traditional classification in the "duration''-"hardness'' domain. Some long-duration GRBs may not have a massive star origin, while some short-duration GRBs may instead have a massive star origin. We propose to systematically study the gamma-ray Swift/BAT, Fermi/GBM- LAT), X-ray (Swift

  18. Multi-wavelength studies of VHE gamma-ray blazars

    NASA Astrophysics Data System (ADS)

    Gall, Daniel D.

    2010-12-01

    Blazars, particularly those detected in TeV gamma-rays, are some of the most violent astrophysical objects yet observered. They display extreme variability on multiple timescales over a broad range of energies. These sources make excellent laboratories for studying the environment within the jets of active galactic nuclei, as the bulk of the detected emission is from the jets. These sources have been well studied at multiple wavelengths, and much insight has been gained into the nature of these extreme objects. This work described in this dissertation attempts to expand the understanding of two particular blazars, Markarian 421 and Markarian 501, by improving on previous observational techniques and utilizing state of the art detectors for obtaining data. The first project described focused on obtaining strictly simultaneous multi-wavelength data, covering a broad energy range, to search for any multi-wavelength correlations and to provide an accurate spectral energy distribution. This simultaneous data is essential for these sources due to their rapid variability. The most widely accepted models for emission within blazars, known as synchrotron self Compton, depend on a strong connection between the X-ray and gamma-ray photons. The simplest of these models predicts a strong correlation between the observed flux in these two bands, but this study did not observe such a correlation, though the synchrotron self Compton models could match the data. The second project focused on obtaining a state of the art measurement of the quiescent state of the blazar Markarian 501. This object is generally quite weak, and previous very high energy (E > 100 GeV) gamma-ray experiments were not able to detect the source in the quiescent state. Neither was the source detected by previous gamma-ray space telescopes operating in a lower energy range. This project used data from the current generation of experiments to obtain a carefully sampled spectral energy distribution of the source

  19. A Multi-wavelength Ozone Lidar for the EASOE Experiment

    NASA Technical Reports Server (NTRS)

    Godin, S.; Ancellet, G.; David, C.; Porteneuve, J.; Leroy, C.; Mitev, V.; Emery, Y.; Flesia, C.; Rizi, V.; Visconti, G.

    1992-01-01

    The study of the ozone layer during winter and springtime in high latitude regions is a major issue in atmospheric research. For a better understanding of these problems, an important experimental campaign called EASOE (European Arctic Stratospheric Ozone Experiment) was organized by the European Community during the winter 1991-1992. Its main objective was to establish a budget of the ozone destruction processes on the whole northern hemisphere. This implied the simultaneous operation of different types of instruments located in both high and mid-latitude regions in order to study the destruction processes as well as the evolution of the ozone layer during the period of the campaign. A description will be given here of a mobile ozone lidar instrument specially designed for operation during the EASOE campaign. This system, which performs ozone measurements in the 5 to 40 km altitude range was located in Sodankyla, Finland as part of the ELSA experiment which also includes operation of another multi-wavelength lidar designed for polar stratospheric cloud measurements.

  20. Multi-wavelength imaging system for the Dutch Open Telescope

    NASA Astrophysics Data System (ADS)

    Bettonvil, Felix C.; Suetterlin, Peter; Hammerschlag, Robert H.; Jagers, Aswin P.; Rutten, Robert J.

    2003-02-01

    The Dutch Open Telescope (DOT) is an innovative solar telescope, completely open, on an open steel tower, without a vacuum system. The aim is long-duration high resolution imaging and in order to achieve this the DOT is equipped with a diffraction limited imaging system in combination with a data acquisition system designed for use with the speckle masking reconstruction technique for removing atmospheric aberrations. Currently the DOT is being equipped with a multi-wavelength system forming a high-resolution tomographic imager of magnetic fine structure, topology and dynamics in the photosphere and low- and high chromosphere. Finally the system will contain 6 channels: G-band (430.5 nm), Ca II H (K) (396.8 nm), H-α (656.3 nm), Ba II (455.4 nm), and two continuum channels (432 and 651 nm). Two channels are in full operation now and observations show that the DOT produces real diffraction limited movies (with 0.2" resolution) over hours in G-band (430.5 nm) and continuum (432 nm).

  1. Multi-Wavelength Spectroscopy of Super-Earth Atmospheres

    NASA Astrophysics Data System (ADS)

    Dragomir, Diana; Benneke, Björn; Crossfield, Ian; Lothringer, Joshua; Knutson, Heather

    2017-01-01

    The Kepler mission has revealed that super-Earths (planets with radii between 1 and 4 R_Earth) are the most common class of planets in the Galaxy, though none are known in our own Solar System. These planets can theoretically have a wide range of compositions which we are just beginning to explore observationally. While studies based on Kepler data have revolutionized many areas of exoplanet research, the relative faintness of most of the host stars in the Kepler field means that atmospheric characterization of these super-Earths with currently available instruments is extremely challenging. However, a handful of transiting super-Earths are within reach of existing facilities. We have pointed both the HST and Spitzer toward these systems in an effort to paint a thorough picture of their atmospheres. Our transmission spectroscopy observations explore the transition region between terrestrial planets and miniature gas giants, and contribute to distinguishing between low-density hydrogen-dominated atmospheres and compact high-metallicity atmospheres. Transmission spectroscopy over a wide wavelength range is also essential to understanding the properties and effects of clouds in these atmospheres. The results of this program will inform the direction to be taken by future multi-wavelength studies of these worlds, in particular those enabled when the HST joins forces with the upcoming JWST.

  2. Multi-wavelength high efficiency laser system for lidar applications

    NASA Astrophysics Data System (ADS)

    Willis, Christina C. C.; Culpepper, Charles; Burnham, Ralph

    2015-09-01

    Motivated by the growing need for more efficient, high output power laser transmitters, we demonstrate a multi-wavelength laser system for lidar-based applications. The demonstration is performed in two stages, proving energy scaling and nonlinear conversion independently for later combination. Energy scaling is demonstrated using a 1064 nm MOPA system which employs two novel ceramic Nd:YAG slab amplifiers, the structure of which is designed to improve the amplifier's thermal performance and energy extraction via three progressive doping stages. This structure improved the extraction efficiency by 19% over previous single-stage dopant designs. A maximum energy of 34 mJ was produced at 500 Hz with a 10.8 ns pulse duration. High efficiency non-linear conversion from 1064 nm to 452 nm is demonstrated using a KTP ring OPO with a BBO intra-cavity doubler pumped with 50 Hz, 16 ns 1064 nm pulses. The OPO generates 1571 nm signal which is frequency doubled to 756 nm by the BBO. Output 786 nm pulses are mixed with the 1064 nm pump pulses to generate 452 nm. A conversion efficiency of 17.1% was achieved, generating 3 mJ of 452 nm pulses of 7.8 ns duration. Pump power was limited by intra-cavity damage thresholds, and in future experiments we anticipate >20% conversion efficiency.

  3. A multi-wavelength view of NGC 1624-2

    NASA Astrophysics Data System (ADS)

    David-Uraz, A.; Petit, V.; MacInnis, R.; Erba, C.; Owocki, S. P.; Fullerton, A. W.; Walborn, N. R.; Cohen, D. H.

    2017-07-01

    Large magnetometric surveys have contributed to the detection of an increasing number of magnetic massive stars, and to the recognition of a population of magnetic massive stellar objects with distinct properties. Among these, NGC 1624-2 possesses the largest magnetic field of any O-type star; such a field confines the stellar wind into a circumstellar magnetosphere, which can be probed using observations at different wavelength regimes. Recent optical and X-ray observations suggest that NGC 1624-2's magnetosphere is much larger than that of any other magnetic O star. By modeling the variations of UV resonance lines, we can constrain its velocity structure. Furthermore, recent spectropolarimetric observations raise the possibility of a more complex field topology than previously expected. Putting all of these multi-wavelength constraints together will allow us to paint a consistent picture of NGC 1624-2 and its surprising behavior, giving us valuable insight into the ve! ry nature of massive star magnetospheres.

  4. Multi-wavelength analysis of young pulsars: an overview.

    NASA Astrophysics Data System (ADS)

    Maritz, J. M.; Meintjes, P. J.; Buchner, S. J.

    Young pulsars emit a broad spectrum of radiation that range from radio to gamma ray energies. These pulsars are considered as rotation powered pulsars that spin rapidly and are strongly magnetized. Following the discovery of pulsars nearly four decades ago, the population of known pulsars already reached a number of roughly two thousand. This known population of pulsars includes both millisecond and normal pulsars that were discovered by several telescopes. We analyze both HartRAO radio data and Fermi gamma ray data of the Vela pulsar. We also explore a proposed method of probing the electron column density of the instellar gas through analyzing the gamma ray diffuse data associated with the Fermi two-year observation. This paper serves as an overview of gamma ray and radio timing analysis of bright young pulsars with respect to the use of open source timing analysis tools (Tempo2, Psrchive, Enrico and the Fermi tools). We reason that the multi-wavelength picture of pulsars can help clarify questions regarding the origin of pulsed radiation emission mechanisms in several energy bands, but that radio observations will prove adequate for timing noise analysis, given the accurate and long radio data sets. The process of identifying gravitational waves in timing data, rests on gaining a deeper insight into the timing noise phenomena.

  5. Multi-wavelength follow-up of ANTARES neutrino alerts

    NASA Astrophysics Data System (ADS)

    Mathieu, Aurore

    2015-10-01

    Transient sources are often associated with the most violent phenomena in the Universe, where the acceleration of hadrons may occur. Such sources include gamma-ray bursts (GRBs), active galactic nuclei (AGN) or core-collapse supernovae (CCSNe), and are promising candidates for the production of high energy cosmic rays and neutrinos. The ANTARES telescope, located in the Mediterranean sea, aims at detecting these high energy neutrinos, which could reveal the presence of a cosmic ray accelerator. However, to enhance the sensitivity to transient sources, a method based on multi-wavelength follow-up of neutrino alerts has been developed within the ANTARES collaboration. This program, denoted as TAToO, triggers a network of robotic optical telescopes and the Swift-XRT with a delay of only a few seconds after a neutrino detection. The telescopes start an observation program of the corresponding region of the sky in order to detect a possible electromagnetic counterpart to the neutrino event. The work presented in this thesis covers the development and implementation of an optical image analysis pipeline, as well as the analysis of optical and X-ray data to search for fast transient sources, such as GRB afterglows, and slowly varying transient sources, such as CCSNe.

  6. 40nm tunable multi-wavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Jia, Qingsong; Wang, Tianshu; Zhang, Peng; Dong, Keyan; Jiang, Huilin

    2014-12-01

    A Brillouin-Erbium multi-wavelength tunable fiber laser at C-band is demostrated. A 10 km long singlemode fiber(SMF), a 6 m long Erbium-doped fiber, two couplers, a wavelength division multiplexer, a isolator, an optical circulator, a 980nm pump laser and a narrow linewidth tunable laser are included in the structure. A segment of 10 km-long single-mode fiber (SMF) between the two ports of a 1×2 coupler is used as Brillouin gain. Ebiumdoped fiber amplifier (EDFA) consists of a segment of 6m er-doped fiber pumped by 980nm laser dioder . A narrow linewidth tunable laser from 1527 to 1607 nm as Brillouin bump, At the Brillouin pump power of 8mW and the 980 nm pump power of 400 mw, 16 output channels with 0.08 nm spacing and tuning range of 40 nm from 1527 nm to 1567 nm are achieved. We realize the tunable output of wavelength by adjusting the 980 nm pump power and the Brillouin pump wavelength. Stability of the multiwavelength fiber laser is also observed.

  7. Multi-wavelength Raman Lidar Measurements For CALIPSO Validation At CNR-IMAA EARLINET Station

    NASA Astrophysics Data System (ADS)

    Amodeo, A.; D'Amico, G.; Mona, L.; Pappalardo, G.

    2006-12-01

    A Raman/elastic lidar for tropospheric aerosol study is operational at CNR-IMAA (40° 36'N, 15° 44'E, 760 m above sea level) since May 2000 in the framework of EARLINET (European Aerosol Research LIdar NETwork), the first lidar network for tropospheric aerosol study on continental scale. This system provides aerosol backscatter coefficient profiles at 1064 nm, and independent measurements of aerosol extinction and backscatter coefficient profiles at 355 and 532 nm. In this way, lidar ratio (i.e. extinction to backscatter ratio) profiles at 355 and 532 nm are also obtained. In addition, the detection of components of backscattered light polarized perpendicular and parallel to the direction of the linearly polarized transmitted laser beam at 532 nm allows the measurements of the aerosol depolarization ratio vertical profiles. High quality multi-wavelength measurements (3 backscatter + 2 extinction) allow the determination of microphysical aerosol properties (refractive index, single-scattering albedo and effective particles radii), while depolarization ratio measurements give information about shape and orientation of aerosolic particles and lidar ratio measurements are important for aerosol characterization. This multi-wavelength system is optimal for the validation of CALIPSO data products: it provides a reference point for depolarization ratio and aerosol backscatter at 532 and 1064 nm measurements with the direct comparison of measurements derived from CALIPSO and our lidar system, furthermore aerosol extinction measurements at 532 nm and 355 nm and backscatter measurements at 355 nm add useful information about microphysical aerosol properties that can be used to improve the retrieval of aerosol backscatter coefficient from pure backscatter lidar. Since 14 June 2006, devoted measurements are performed at CNR-IMAA in coincidence of CALIPSO overpasses (maximum 80 km and 2 hours of spatial and temporal distance). First results of the CNR-IMAA observations for

  8. A multi-wavelength, high-contrast contact radiography system for the study of low-density aerogel foams [A multi-wavelength, high-contrast contact radiography system for the study of lowdensity aerogel foams

    SciTech Connect

    Opachich, Y. P.; Koch, J. A.; Haugh, M. J.; Romano, E.; Lee, J. J.; Huffman, E.; Weber, F. A.; Bowers, J. W.; Benedetti, L. R.; Wilson, M.; Prisbrey, S. T.; Wehrenberg, C. E.; Baumann, T. F.; Lenhardt, J. M.; Cook, A.; Arsenlis, A.; Park, H. -S.; Remington, B. A.

    2016-07-21

    A multi wavelength, high contrast contact radiography system has been developed to characterize density variations in ultralow density aerogel foams. These foams are used to generate a ramped pressure drive in materials strength experiments at the National Ignition Facility (NIF) and require precision characterization in order to reduce errors in measurements. The system was used to characterize density variations in carbon and silicon based aerogels to ~10.3% accuracy with ~30 μm spatial resolution. The system description, performance and measurement results collected using a 17.8 mg/cc carbon based JX–6 (C20H30) aerogel are discussed in this paper.

  9. A multi-wavelength, high-contrast contact radiography system for the study of low-density aerogel foams [A multi-wavelength, high-contrast contact radiography system for the study of lowdensity aerogel foams

    DOE PAGES

    Opachich, Y. P.; Koch, J. A.; Haugh, M. J.; ...

    2016-07-21

    A multi wavelength, high contrast contact radiography system has been developed to characterize density variations in ultralow density aerogel foams. These foams are used to generate a ramped pressure drive in materials strength experiments at the National Ignition Facility (NIF) and require precision characterization in order to reduce errors in measurements. The system was used to characterize density variations in carbon and silicon based aerogels to ~10.3% accuracy with ~30 μm spatial resolution. The system description, performance and measurement results collected using a 17.8 mg/cc carbon based JX–6 (C20H30) aerogel are discussed in this paper.

  10. Multi-wavelength studies of wind driving cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Witherick, Dugan Kenneth

    This thesis presents several case studies of disc winds from high-state cataclysmic variable stars, based on multi-wavelength time-series spectroscopy. The research presented here primarily focuses on three low-inclination, nova-like systems: RW Sextansis, V592 Cassiopeiae and BZ Camelopardalis. The aim was to derive and compare key spectral line diagnostics of the outflows, spanning a wide range of ionisation and excitation using (new) FUSE, HST, IUE and optical data. Analysis of the far-UV time-series of RW Sex reveals the wind to be highly variable but generally confined to between ~ -1000 and ~ 0 km/s for all ionisation states; no evidence of the wind at red-shifted velocities is found. This wind is modulated on the orbital period of the system and it is argued that the observed variability is due to changes in the blue-shifted absorption rather than a variable velocity emission. The Balmer profiles observed in the optical time-series of V592 Cas were found to be characterised by three components: a broad, shallow absorption trough, a narrow central emission and a blue-shifted absorption from the disc wind. The wind is also found to be modulated on the systems orbital period, although this modulation is slightly out of phase with the Balmer emission radial velocities. The wind of BZ Cam was found to behave very differently to that of RW Sex and V592 Cas. At times, it was seen (in the Balmer lines and some of the He I lines) to be extremely strong and variable but at other times is was seemingly not present; there was no evidence to suggest that it is modulated on the orbital or any other period. This study is an immense source of data on CV disc winds and importantly tries to parameterise three nova-like CVs to understand the similarities and differences between them and their winds.

  11. Multi-Wavelength Radar Studies of Lunar Pyroclastic Deposits

    NASA Astrophysics Data System (ADS)

    Carter, Lynn M.; Campbell, B. A.; Hawke, B. R.; Campbell, D. B.; Nolan, M. C.

    2008-09-01

    Lunar pyroclastic deposits were formed early in the Moon's history and are comprised of fine-grained, glassy materials. These low-albedo features are typically associated with mare boundaries, sites of mare volcanism, and fractures in and around impact craters. Optical, ultraviolet and infrared data have been used to map the locations of over one hundred pyroclastic deposits and to study their compositional differences (e.g. Gaddis et al., Icarus, 161, 262, 2003; Weitz et al., JGR, 103, 22725, 1998). We use multi-wavelength radar observations to study the distribution, depth and embedded rock abundance of these deposits. Data were acquired at S-band (12.6 cm wavelength) and P-band (70 cm wavelength) using Arecibo Observatory and the Green Bank Telescope in a bistatic configuration. The P-band images have resolutions of 150 m/pixel; S-band images have resolutions between 20 and 80 m/pixel. Pyroclastic deposits appear dark to the radar at both observed wavelengths because they are smooth, easily penetrable by radar waves, and generally contain few embedded blocks. At S-band wavelengths, changes in radar reflectivity across some of the pyroclastic deposits highlight areas with increased rock abundance. Radar circular polarization ratio maps can be used to identify fine-grained deposits in cases where optical or near-infrared data are ambiguous about the presence of pyroclastics. In some cases, data from multiple radar wavelengths (including archival 3.8 cm wavelength data) can place constraints on the deposit depth. We will present results for pyroclastic deposits surrounding Mare Serenitatis, including Sulpicius Gallus, Rima Menelaus, and Taurus-Littrow, as well as new polarimetry of the Aristarchus Plateau that compliments work done by Campbell et al. (2008, Geology, 36, 135). The S-band data are part of a larger study to map the entire lunar nearside at 80 m/pixel resolution.

  12. A multi-scale, multi-wavelength source extraction method: getsources

    NASA Astrophysics Data System (ADS)

    Men'shchikov, A.; André, Ph.; Didelon, P.; Motte, F.; Hennemann, M.; Schneider, N.

    2012-06-01

    We present a multi-scale, multi-wavelength source extraction algorithm called getsources. Although it has been designed primarily for use in the far-infrared surveys of Galactic star-forming regions with Herschel, the method can be applied to many other astronomical images. Instead of the traditional approach of extracting sources in the observed images, the new method analyzes fine spatial decompositions of original images across a wide range of scales and across all wavebands. It cleans those single-scale images of noise and background, and constructs wavelength-independent single-scale detection images that preserve information in both spatial and wavelength dimensions. Sources are detected in the combined detection images by following the evolution of their segmentation masks across all spatial scales. Measurements of the source properties are done in the original background-subtracted images at each wavelength; the background is estimated by interpolation under the source footprints and overlapping sources are deblended in an iterative procedure. In addition to the main catalog of sources, various catalogs and images are produced that aid scientific exploitation of the extraction results. We illustrate the performance of getsources on Herschel images by extracting sources in sub-fields of the Aquila and Rosette star-forming regions. The source extraction code and validation images with a reference extraction catalog are freely available.

  13. Analysis of complex samples using a portable multi-wavelength light emitting diode (LED) fluorescence spectrometer

    USDA-ARS?s Scientific Manuscript database

    Spectroscopic analysis of chemically complex samples often requires an increase n the dimensionality of the measured response surface. This often involves the measurement of emitted light intensities as functions of both wavelengths of excitation and emission resulting in the generation of an excita...

  14. Multi-wavelength fine structure and mass flows in solar microflares

    NASA Astrophysics Data System (ADS)

    Berkebile-Stoiser, S.; Gömöry, P.; Veronig, A. M.; Rybák, J.; Sütterlin, P.

    2009-10-01

    Aims: We study the multi-wavelength characteristics at high spatial resolution, as well as chromospheric evaporation signatures of solar microflares. To this end, we analyze the fine structure and mass flow dynamics in the chromosphere, transition region and corona of three homologous microflares (GOES class multi-wavelength analysis using temporally and spatially highly resolved imaging data from the Dutch open telescope (Hα, Ca ii H), the transition region and coronal explorer (17.1 nm), the extreme-ultraviolet imaging telescope (19.5 nm), and the Reuven Ramaty high energy solar spectroscopic imager (≳3 keV) was carried out. EUV line spectra provided by the coronal diagnostic spectrometer are searched for Doppler shifts in order to study associated plasma flows at chromospheric (He i, T˜3.9× 104 K), transition region (e.g. O v, T˜ 2.6× 105 K), and coronal temperatures (Si xii, T˜ 2× 106 K). RHESSI X-ray spectra provide information about non-thermal electrons. Results: The multi-wavelength appearance of the microflares is in basic agreement with the characteristics of large flares. For the first event, a complex flare sequence is observed in TRACE 17.1 nm images (T≈ 1 MK), which show several brightenings, narrow loops of enhanced emission, and an EUV jet. EIT 19.5 nm data (T≈ 1.5 MK) exhibit similar features for the third event. DOT measurements show finely structured chromospheric flare brightenings for all three events, loop-shaped fibrils of increased emission between Hα brightenings, as well as a similar feature in Ca ii. For all three events, a RHESSI X-ray source (3-8 keV, T ≳ 10 MK) is located in between two chromospheric brightenings situated in magnetic flux of opposite polarity. We find the flow dynamics associated with the events to be very complex. In the chromosphere and transition region, CDS observed downflows for the first (v ≲ 40 km s-1), and

  15. V404 Cygni: coordination of multi-wavelength observations and request for coverage during HST visits

    NASA Astrophysics Data System (ADS)

    Knigge, C.; Marsh, T. R.; Sivakoff, G. R.; Altamirano, D.; Hernández Santisteban, J. V.; Shaw, A.; Charles, P. A.; Gandhi, P.

    2015-06-01

    In an effort to coordinate the multi-wavelength observations covering the ongoing outburst of the black hole X-ray transient V404 Cygni, we have set up a mailing list to facilitate communication between observers.

  16. Measurement of nonlinear refractive index based on multiple configuration of FBG in generating multi wavelength

    NASA Astrophysics Data System (ADS)

    Abdullah, Mohd Nizam; Shaari, Sahbudin; Ehsan, Abang Annuar; Menon, Susthitha; Zakaria, Osman

    2015-06-01

    A reliable method for measurement of the nonlinear refractive index through application of multi wavelength phenomenon. Multi wavelength realisation based on Erbium doped fibre laser (EDFL) is proposed and experimentally demonstrated. A combination of 15 m high efficiency Erbium doped fibre (EDF) and a 20 m Photonic Crystal Fibre (PCF) as main catalyst to suppress the homogenous broadening of EDF and to obtain highly stability of multi wavelength through insertion of a set of fibre Bragg gratings (FBGs) in the cavity. This PCF has zero dispersion of 1040 nm which mismatch from transmission window of 1550 nm. A reliable repeatability of multi wavelength based on multiple configuration of FBGs less than 0.2% obtained. This consistent results influence in determination of nonlinear refractive index by relation of four wave mixing (FWM).

  17. De-blending deep Herschel surveys: A multi-wavelength approach

    NASA Astrophysics Data System (ADS)

    Pearson, W. J.; Wang, L.; van der Tak, F. F. S.; Hurley, P. D.; Burgarella, D.; Oliver, S. J.

    2017-07-01

    Aims: Cosmological surveys in the far-infrared are known to suffer from confusion. The Bayesian de-blending tool, XID+, currently provides one of the best ways to de-confuse deep Herschel SPIRE images, using a flat flux density prior. This work is to demonstrate that existing multi-wavelength data sets can be exploited to improve XID+ by providing an informed prior, resulting in more accurate and precise extracted flux densities. Methods: Photometric data for galaxies in the COSMOS field were used to constrain spectral energy distributions (SEDs) using the fitting tool CIGALE. These SEDs were used to create Gaussian prior estimates in the SPIRE bands for XID+. The multi-wavelength photometry and the extracted SPIRE flux densities were run through CIGALE again to allow us to compare the performance of the two priors. Inferred ALMA flux densities (FinferALMA), at 870 μm and 1250 μm, from the best fitting SEDs from the second CIGALE run were compared with measured ALMA flux densities (FmeasALMA) as an independent performance validation. Similar validations were conducted with the SED modelling and fitting tool MAGPHYS and modified black-body functions to test for model dependency. Results: We demonstrate a clear improvement in agreement between the flux densities extracted with XID+ and existing data at other wavelengths when using the new informed Gaussian prior over the original uninformed prior. The residuals between FmeasALMA and FinferALMA were calculated. For the Gaussian priors these residuals, expressed as a multiple of the ALMA error (σ), have a smaller standard deviation, 7.95σ for the Gaussian prior compared to 12.21σ for the flat prior; reduced mean, 1.83σ compared to 3.44σ; and have reduced skew to positive values, 7.97 compared to 11.50. These results were determined to not be significantly model dependent. This results in statistically more reliable SPIRE flux densities and hence statistically more reliable infrared luminosity estimates. Herschel

  18. A multi-wavelength database of water vapor in planet-forming regions

    NASA Astrophysics Data System (ADS)

    Pontoppidan, Klaus

    The inner few astronomical units of gas-rich protoplanetary disk are environments characterized by a rich and active gaseous chemistry. Primitive material left over from the formation of our own Solar System has for a long time yielded tantalizing clues to a heterogenous nebula with intricate dynamical, thermal and chemical structure that ultimately led to a great diversity in the planets and planetesimals of the Solar System. The discovery of a rich chemistry in protoplanetary disks via a forest of strong 3-40 micron molecular emission lines (H2O, OH, CO2, HCN, C2H2,...) allows us for the first time to investigate chemical diversity in other planet-forming environmments (Salyk et al. 2008; Carr & Najita 2008). Further efforts, supported by the Origins program, has established that this molecular forest is seen in the disks surrounding most young solar- type stars (Pontoppidan et al. 2010). We propose a 3-year program to analyze our growing multi-wavelength database of observations of water, OH and organic molecules in the surfaces of protoplanetary disks. The database includes high (R~25,000-100,000) and medium resolution (R~600-3000) 3- 200 micron spectra from a wide range of facilities (Keck-NIRSPEC, VLT-CRIRES, Spitzer-IRS, VLT-VISIR, Gemini-Michelle and Herschel-PACS). Our previous efforts have focused on demonstrating feasibility for observing water and other molecules in planet-forming regions, building statistics to show that the molecular forest is ubiquitous in disks around low-mass and solar-type stars and taking the first steps in understanding the implied chemical abundances. Now, as the next logical step, we will combine multi- wavelength data from our unique multi-wavelength database to map the radial distribution of, in particular, water and its derivatives. 1) Â We will use both line profile information from the high-resolution spectra, as well as line strengths, from a combination of high and low temperature lines to constrain the radial

  19. A multi-wavelength database of water vapor in planet-forming regions

    NASA Astrophysics Data System (ADS)

    Pontoppidan, Klaus

    The inner few astronomical units of gas-rich protoplanetary disk are environments characterized by a rich and active gaseous chemistry. Primitive material left over from the formation of our own Solar System has for a long time yielded tantalizing clues to a heterogenous nebula with intricate dynamical, thermal and chemical structure that ultimately led to a great diversity in the planets and planetesimals of the Solar System. The discovery of a rich chemistry in protoplanetary disks via a forest of strong 3-40 micron molecular emission lines (H2O, OH, CO2, HCN, C2H2,...) allows us for the first time to investigate chemical diversity in other planet-forming environmments (Salyk et al. 2008; Carr & Najita 2008). Further efforts, supported by the Origins program, has established that this molecular forest is seen in the disks surrounding most young solar- type stars (Pontoppidan et al. 2010). We propose a 3-year program to analyze our growing multi-wavelength database of observations of water, OH and organic molecules in the surfaces of protoplanetary disks. The database includes high (R~25,000-100,000) and medium resolution (R~600-3000) 3- 200 micron spectra from a wide range of facilities (Keck-NIRSPEC, VLT-CRIRES, Spitzer-IRS, VLT-VISIR, Gemini-Michelle and Herschel-PACS). Our previous efforts have focused on demonstrating feasibility for observing water and other molecules in planet-forming regions, building statistics to show that the molecular forest is ubiquitous in disks around low-mass and solar-type stars and taking the first steps in understanding the implied chemical abundances. Now, as the next logical step, we will combine multi- wavelength data from our unique multi-wavelength database to map the radial distribution of, in particular, water and its derivatives. 1) We will use both line profile information from the high-resolution spectra, as well as line strengths, from a combination of high and low temperature lines to constrain the radial abundance

  20. Programmable Illumination and High-Speed, Multi-Wavelength, Confocal Microscopy Using a Digital Micromirror

    PubMed Central

    Martial, Franck P.; Hartell, Nicholas A.

    2012-01-01

    Confocal microscopy is routinely used for high-resolution fluorescence imaging of biological specimens. Most standard confocal systems scan a laser across a specimen and collect emitted light passing through a single pinhole to produce an optical section of the sample. Sequential scanning on a point-by-point basis limits the speed of image acquisition and even the fastest commercial instruments struggle to resolve the temporal dynamics of rapid cellular events such as calcium signals. Various approaches have been introduced that increase the speed of confocal imaging. Nipkov disk microscopes, for example, use arrays of pinholes or slits on a spinning disk to achieve parallel scanning which significantly increases the speed of acquisition. Here we report the development of a microscope module that utilises a digital micromirror device as a spatial light modulator to provide programmable confocal optical sectioning with a single camera, at high spatial and axial resolution at speeds limited by the frame rate of the camera. The digital micromirror acts as a solid state Nipkov disk but with the added ability to change the pinholes size and separation and to control the light intensity on a mirror-by-mirror basis. The use of an arrangement of concave and convex mirrors in the emission pathway instead of lenses overcomes the astigmatism inherent with DMD devices, increases light collection efficiency and ensures image collection is achromatic so that images are perfectly aligned at different wavelengths. Combined with non-laser light sources, this allows low cost, high-speed, multi-wavelength image acquisition without the need for complex wavelength-dependent image alignment. The micromirror can also be used for programmable illumination allowing spatially defined photoactivation of fluorescent proteins. We demonstrate the use of this system for high-speed calcium imaging using both a single wavelength calcium indicator and a genetically encoded, ratiometric, calcium

  1. Programmable illumination and high-speed, multi-wavelength, confocal microscopy using a digital micromirror.

    PubMed

    Martial, Franck P; Hartell, Nicholas A

    2012-01-01

    Confocal microscopy is routinely used for high-resolution fluorescence imaging of biological specimens. Most standard confocal systems scan a laser across a specimen and collect emitted light passing through a single pinhole to produce an optical section of the sample. Sequential scanning on a point-by-point basis limits the speed of image acquisition and even the fastest commercial instruments struggle to resolve the temporal dynamics of rapid cellular events such as calcium signals. Various approaches have been introduced that increase the speed of confocal imaging. Nipkov disk microscopes, for example, use arrays of pinholes or slits on a spinning disk to achieve parallel scanning which significantly increases the speed of acquisition. Here we report the development of a microscope module that utilises a digital micromirror device as a spatial light modulator to provide programmable confocal optical sectioning with a single camera, at high spatial and axial resolution at speeds limited by the frame rate of the camera. The digital micromirror acts as a solid state Nipkov disk but with the added ability to change the pinholes size and separation and to control the light intensity on a mirror-by-mirror basis. The use of an arrangement of concave and convex mirrors in the emission pathway instead of lenses overcomes the astigmatism inherent with DMD devices, increases light collection efficiency and ensures image collection is achromatic so that images are perfectly aligned at different wavelengths. Combined with non-laser light sources, this allows low cost, high-speed, multi-wavelength image acquisition without the need for complex wavelength-dependent image alignment. The micromirror can also be used for programmable illumination allowing spatially defined photoactivation of fluorescent proteins. We demonstrate the use of this system for high-speed calcium imaging using both a single wavelength calcium indicator and a genetically encoded, ratiometric, calcium

  2. Effect of spatial coherence of LED sources on image resolution in holographic displays

    NASA Astrophysics Data System (ADS)

    Pourreza Ghoushchi, Vahid; Aas, Mehdi; Ulusoy, Erdem; Ürey, Hakan

    2017-02-01

    Holographic Displays (HDs) provide 3D images with all natural depth cues via computer generated holograms (CGHs) implemented on spatial light modulators (SLMs). HDs are coherent light processing systems based on interference and diffraction, thus they generally use laser light. However, laser sources are relatively expensive, available only at some particular wavelengths and difficult to miniaturize. In addition, highly coherent nature of laser light makes some undesired visual effects quite evident, such as speckle noise, interference due to stray light or defects of optical components. On the other hand, LED sources are available in variety of wavelengths, has small die size, and no speckle artifact. However, their finite spatial size introduce some degree of spatial incoherence in an HD system and degrade image resolution, which is the subject of the study in this paper. Our theoretical analysis indicates that the amount of resolution loss depends on the distance between hologram and SLM image planes. For some special configurations, the source size has no effect at all. We also performed experiments with different configurations using lasers and LEDs with different emission areas that vary from 50 μm to 200 μm, and determined Contrast Transfer Function (CTF) curves which agree well with our theoretical model. The results show that it is possible to find configurations where LEDs combined with pinholes almost preserve natural resolution limit of human eye while keeping the loss in light efficiency within tolerable limits.

  3. Multi-wavelength laser tuning based on cholesteric liquid crystals with nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Sheng-Chieh; Lin, Jia-De; Lee, Chia-Rong; Hwang, Shug-June

    2016-04-01

    A controllable multi-wavelength laser from a dye-doped cholesteric liquid crystal (DDCLC) cell is demonstrated by incorporating self-assembled polyhedral oligomeric silsesquioxane (POSS) nanoparticles (NPs). Multi-wavelength lasing emission is achieved by formation of multiple planar domains; this formation is dominantly influenced by the vertical alignment of NP clusters adsorbed on the substrate surface through a rapid thermal annealing process. The multi-wavelength lasing peaks are generated through the resultant effect of multiple longitudinal resonant modes of a Fabry-Pérot etalon between the cell substrates and the amplification of fluorescence photons with the resonant wavelengths within the broadening long-wavelength edge of the reflection band of the multi-domain CLC. The amount of multi-wavelength lasing peaks can be controlled by changing the POSS NP concentration and the cooling rate of the cell. Furthermore, thermo-reversible control of the multi-wavelength lasing emission can be attained by controlling the thermally induced phase separation process of the POSS/DDCLC cell via a heating/cooling cyclic process.

  4. Multi-wavelength polarimetric studies of relativistic jets in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Casadio, Carolina

    This Thesis is focussed on the study of relativistic jets, commonly present in multiple astrophysical sites, from active galactic nuclei (AGN), to micro- quasars or gamma-ray bursts (GRBs). In the case of AGN, huge amounts of energy across the whole electromagnetic spectrum are released as a conse- quence of the accretion of material onto a supermassive back hole (SMBH) lurking at their centers. The accretion leads to the formation of a pair of very powerful and highly collimated jets extending far beyond the size of the host galaxy. We analyzed the correlation between the multi-wavelength emission and the radio jet in three powerful AGN, the radio galaxies 3C 120 and M 87, and the quasar CTA 102. The main goal of this Thesis is to obtain a better understanding of the jet dynamics and the role played by the magnetic field, and to determine what are the sites and mechanisms for the production of the γ-ray emission observed in these sources. We have performed multi-wavelength studies of the radio galaxy 3C 120 and the blazar CTA 102 during unprecedented γ-ray flares for both sources. The NASA satellite Fermi registered in September-October 2012 a bright γ-ray flare in CTA 102, and between December 2012 and October 2014 a prolonged γ-ray activity in the radio galaxy 3C 120. In both studies, to determine where the γ-ray emission is produced, the analysis of Fermi data has been compared with a detailed study of the morphology and evolution of the parsec scale jet through a series of extremely-high angular resolution Very Long Baseline Array (VLBA) images at 43 GHz from the Boston University blazar monitoring program, in which our research group is actively participating. In the case of 3C 120 we have also collected 15 GHz VLBA data from the MOJAVE monitoring program, extending our study of the radio jet from June 2008 to May 2014. For the study of CTA 102 a total of 80 VLBA images at 43 GHz have been analyzed and compared with observations across the whole

  5. Design and implementation of real-time LED spatial radiance measurement systems

    NASA Astrophysics Data System (ADS)

    Chang, Gao-Wei; Yeh, Zong-Mu; Liao, Chia-Cheng

    2007-02-01

    Light-emitting diodes (LEDs) have been recognized as a generation of new light sources because they possess the properties of energy-saving, environmental protection, long lifetime, and those lacking in conventional lighting. To satisfy the requirements for different applications (e.g., for large-scale displays), determining the spatial radiances of LEDs is important to identifying their viewing angle and utilizing their lighting efficiency. The objective of this paper is to build up a real-time spatial radiance measurement system for LEDs, on the basis of digital signal processing (DSP) techniques. In this paper, the system analysis is given to show the feasibility of this work. Two primary subsystems are devised to perform the real-time measurements. First, in the optoelectronic sensing and signal processing subsystem, a wide-bandwidth photodiode sensing circuit is employed to acquire optical signals at a high speed, and an automatic gain control (AGC) circuit is designed to increase the measurement range. To support high-speed data processing, a DSP-based platform is developed in the subsystem. Second, a light-source rotation scheme is used in the optomechanical subsystem. For performance evaluations, we adopt a standard calibrating light source to test and verify our system. Experimental results indicate that the proposed system gives satisfactory results.

  6. Touch the Invisible Sky: A multi-wavelength Braille book featuring NASA images

    NASA Astrophysics Data System (ADS)

    Steel, S.; Grice, N.; Daou, D.

    2008-06-01

    Multi-wavelength astronomy - the study of the Universe at wavelengths beyond the visible, has revolutionised our understanding and appreciation of the cosmos. Hubble, Chandra and Spitzer are examples of powerful, space-based telescopes that complement each other in their observations spanning the electromagnetic spectrum. While several Braille books on astronomical topics have been published, to this point, no printed material accessible to the sight disabled or Braille reading public has been available on the topic of multi-wavelength astronomy. Touch the Invisible Sky presents the first printed introduction to modern, multi-wavelength astronomy studies to the disabled sight community. On a more fundamental level, tactile images of a Universe that had, until recently, been invisible to all, sighted or non-sighted, is an important learning message on how science and technology broadens our senses and our understanding of the natural world.

  7. Quantum dot SOA/silicon external cavity multi-wavelength laser.

    PubMed

    Zhang, Yi; Yang, Shuyu; Zhu, Xiaoliang; Li, Qi; Guan, Hang; Magill, Peter; Bergman, Keren; Baehr-Jones, Thomas; Hochberg, Michael

    2015-02-23

    We report a hybrid integrated external cavity, multi-wavelength laser for high-capacity data transmission operating near 1310 nm. This is the first demonstration of a single cavity multi-wavelength laser in silicon to our knowledge. The device consists of a quantum dot reflective semiconductor optical amplifier and a silicon-on-insulator chip with a Sagnac loop mirror and microring wavelength filter. We show four major lasing peaks from a single cavity with less than 3 dB power non-uniformity and demonstrate error-free 4 × 10 Gb/s data transmission.

  8. [Solid-state multi-wavelength lasers equipment for retina treatment].

    PubMed

    Liu, Wenlu; Zhou, Chuanqing; Ren, Qiushi

    2012-09-01

    Solid-state multi-wavelength laser equipment is the treatment device with selected wavelength Nd: YAG laser frequency technology, integrated red (659 nm), yellow (589 nm) and green (532 nm) of three solid-state lasers. The device is designed by the accurate controlled laser output system, precision optical and electronic control through the optical coupler into the optical fiber transmission system. It's combined with an eye slit lamp integration of high precision, good stability stability for all solid-state multi-wavelength lasers equipment.

  9. Multi-wavelength optical dazzler for personnel and sensor incapacitation

    NASA Astrophysics Data System (ADS)

    Donne, G. Alexsana; Hauck, James P.; Ludman, Jacques; Moldow, Roberta; Servatius, Rick; Yagrich, Kenneth

    2006-05-01

    We have performed analysis of the requirements for an optical dazzler, designed and built a three-wavelength source with a baseline beam projector, and a Smart Beam Projector that can point the beam, and adjust the laser power for a particular target. The source is based on diode lasers, and diode pumped lasers in the Red, Green and Violet ranges of wavelengths. Each laser can be independent adjusted in output power, and pulse duration. The beams are combined using optical fibers, and the source fits in a 1/4 cubic foot Pelican Box, and can run off a battery for field testing. The baseline beam projector can be mounted to a rifle or pistol. The Smart beam projector is designed for laboratory testing at this time. The operation of the prototype system will allow a variety of combinations of laser power, and pulse length to give a varying spatial and temporal profile of illumination. The system is to be tested by the Army for effectiveness. A next generation of dazzler is under construction that will allow microprocessor control of pulse power and duration, increasing the variety of illumination spatial and temporal patterns and more fully utilizing the Smart beam projector capabilities.

  10. THEoretical Modelling and multi-wavelength Observations of evolved Stars (THEMOS)

    NASA Astrophysics Data System (ADS)

    Uscanga, L.; Boumis, P.

    2013-09-01

    Planetary Nebulae (PNe) are one of the last phases in the evolution of low/intermediate mass stars (<8Msun), characterized by extended diffuse ionized and neutral gas surrounding the dying hot cores of highly evolved stars. Their immediate precursors are stars in the asymptotic giant branch (AGB), characterized by a strong mass-loss, followed by a short (100-10000 yr) transitional post-AGB phase. While the morphology of the mass-loss processes in the AGB phase is usually spherically symmetric, PNe show complex bipolar or multipolar structures. Diverse structural components of these evolved stars can be observed at different wavelengths, i.e., 1) ionised bipolar/multipolar structures in PNe, observed from optical to cm-wavelengths; 2) maser emission tracing outflows/discs in post- AGBs/extremely young Pne, observed at cm-wavelengths; 3) circumstellar molecular gas presumably tracing dense toroidal structures towards the centre of PNe, observed at mm/submm-wavelengths. These multi wavelength studies together with theoretical modelling (3D hydrodynamical simulations, kinematical models, and radiative transfer studies) are important to derive a complete picture of the evolution of low/intermediate mass stars. The aim of THEMOS project is to determine the genesis of the asymmetry in these evolved stars by studying their physical conditions, morphology, and kinematics of ionized and neutral gas. These studies will cover a wide range of spatial scales from hundreds of AU for optical studies, down to a few AU, using radio interferometric techniques. We will present our first results from our radio interferometric observations in PNe, as well as the hydrodynamical modeling of the morphology and kinematics of the PN NGC 6302.

  11. Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results

    NASA Technical Reports Server (NTRS)

    Clark, Beth Ellen; Shepard, M.; Bus, S. J.; Vilas, F.; Rivkin, A. S.; Lim, L.; Lederer, S.; Jarvis, K.; Shah, S.; McConnochie, T.

    2004-01-01

    The August 2003 apparition of asteroid 2100 Ra-Shalom brought together a collaboration of observers with the goal of obtaining rotationally resolved multiwavelength spectra at each of 5 facilities: infrared spectra at the NASA Infrared Telescope Facility (Clark and Shepard), radar images at Arecibo (Shepard and Clark), thermal infrared spectra at Palomar (Lim, McConnochie and Bell), visible spectra at McDonald Observatory (Vilas, Lederer and Jarvis), and visible lightcurves at Ondrojev Observatory (Pravec). The radar data was to be used to develop a high spatial resolution physical model to be used in conjunction with spectral data to investigate compositional and textural properties on the near surface of Ra Shalom as a function of rotation phase. This was the first coordinated multi-wavelength investigation of any Aten asteroid. There are many reasons to study near-Earth asteroid (NEA) 2100 Ra-Shalom: 1) It has a controversial classification (is it a C- or K-type object)? 2) There would be interesting dynamical ramifications if Ra-Shalom is a K-type because most K-types come from the Eos family and there are no known dynamical pathways from Eos to the Aten population. 3) The best available spectra obtained previously may indicate a heterogeneous surface (most asteroids appear to be fairly homogeneous). 4) Ra-Shalom thermal observations obtained previously indicated a lack of regolith, minimizing the worry of space weathering effects in the spectra. 5) Radar observations obtained previously hinted at interesting surface structures. 6) Ra-Shalom is one of the largest Aten objects. And 7) Ra-Shalom is on a short list of proposed NEAs for spacecraft encounters and possible sample returns. Preliminary results from the visible, infrared, and thermal spectroscopy measurements will be presented here.

  12. Synthetic 3D modeling of active regions and simulation of their multi-wavelength emission

    NASA Astrophysics Data System (ADS)

    Nita, Gelu M.; Fleishman, Gregory; Kuznetsov, Alexey A.; Loukitcheva, Maria A.; Viall, Nicholeen M.; Klimchuk, James A.; Gary, Dale E.

    2015-04-01

    To facilitate the study of solar active regions, we have created a synthetic modeling framework that combines 3D magnetic structures obtained from magnetic extrapolations with simplified 1D thermal models of the chromosphere, transition region, and corona. To handle, visualize, and use such synthetic data cubes to compute multi-wavelength emission maps and compare them with observations, we have undertaken a major enhancement of our simulation tools, GX_Simulator (ftp://sohoftp.nascom.nasa.gov/solarsoft/packages/gx_simulator/), developed earlier for modeling emission from flaring loops. The greatly enhanced, object-based architecture, which now runs on Windows, Mac, and UNIX platform, offers important new capabilities that include the ability to either import 3D density and temperature distribution models, or to assign to each individual voxel numerically defined coronal or chromospheric temperature and densities, or coronal Differential Emission Measure distributions. Due to these new capabilities, the GX_Simulator can now apply parametric heating models involving average properties of the magnetic field lines crossing a given voxel volume, as well as compute and investigate the spatial and spectral properties of radio (to be compared with VLA or EOVSA data), (sub-)millimeter (ALMA), EUV (AIA/SDO), and X-ray (RHESSI) emission calculated from the model. The application integrates shared-object libraries containing fast free-free, gyrosynchrotron, and gyroresonance emission codes developed in FORTRAN and C++, and soft and hard X-ray and EUV codes developed in IDL. We use this tool to model and analyze an active region and compare the synthetic emission maps obtained in different wavelengths with observations.This work was partially supported by NSF grants AGS-1250374, AGS-1262772, NASA grant NNX14AC87G, the Marie Curie International Research Staff Exchange Scheme "Radiosun" (PEOPLE-2011-IRSES-295272), RFBR grants 14-02-91157, 15-02-01089, 15-02-03717, 15

  13. A multi-wavelength, high-contrast contact radiography system for the study of low-density aerogel foams

    SciTech Connect

    Opachich, Y. P. Koch, J. A.; Haugh, M. J.; Romano, E.; Lee, J. J.; Huffman, E.; Weber, F. A.; Bowers, J. W.; Benedetti, L. R.; Wilson, M.; Prisbrey, S. T.; Wehrenberg, C. E.; Baumann, T. F.; Lenhardt, J. M.; Cook, A.; Arsenlis, A.; Park, H.-S.; Remington, B. A.

    2016-07-15

    A multi-wavelength, high contrast contact radiography system has been developed to characterize density variations in ultra-low density aerogel foams. These foams are used to generate a ramped pressure drive in materials strength experiments at the National Ignition Facility and require precision characterization in order to reduce errors in measurements. The system was used to characterize density variations in carbon and silicon based aerogels to ∼10.3% accuracy with ∼30 μm spatial resolution. The system description, performance, and measurement results collected using a 17.8 mg/cc carbon based JX–6 (C{sub 20}H{sub 30}) aerogel are discussed in this manuscript.

  14. Dark matter indirect searches: Multi-wavelength and anisotropies

    NASA Astrophysics Data System (ADS)

    Ando, Shin'ichiro

    2016-05-01

    If dark matter is made of particles governed by weak-scale physics, they may annihilate or decay to leave observable signatures in high-energy gamma-ray sky. In addition, any charged particles produced by the same process will also give low-frequency photons through successive electromagnetic interactions. Plenty of data from modern astrophysical measurements of various wavelengths, especially gamma rays, enabled new analysis techniques to search for these dark matter signatures with an unprecedented sensitivities. Since it is very likely that signatures of dark matter annihilation or decay is hidden in the gamma-ray data, one should fully utilize all available data including: (1) energy spectrum of all wavelengths ranging from radio to very-high-energy gamma rays; (2) spatial clustering probed with the angular power spectrum of the gamma-ray background; (3) cross correlation between the gamma-ray distribution with nearby galaxy catalogs; and (4) gamma-ray-flux distribution. I will review recent theoretical and observational developments in all these aspects, and discuss prospects for the future towards discovery of dark matter as an elementary particle in physics beyond the standard model.

  15. Multi-Wavelength Study of Active Region Loop Dynamics

    NASA Astrophysics Data System (ADS)

    Banerjee, D.

    2006-11-01

    Observations have revealed the existence of weak transient disturbances in extended coronal loop systems. These propagating disturbances (PDs) originate from small scale brightenings at the footpoints of the loops and propagate upward along the loops. In all cases observed, the projected propagation speed is close to, but below the expected sound speed in the loops. This suggests that the PDs could be interpreted as slow mode MHD waves. Interpreting the oscillation in terms of different wave modes and/or plasma motions always depend on the line of sight as we observe in the limb or on the center of the disk. The JOP 165 campaign will address some of these questions. MDI and TRACE photospheric and UV imaging of TRACE and SPIRIT have been acquired simultaneously with high temporal and spatial coverage along with the spectroscopic data from CDS. EIT was operated in the shutter-less mode to achieve high Cadence. Some of the off- limb active region dynamics and oscillations observed during this JOP campaign will be focused in this presentation. Plasma condensations and temporal variations in active region loops will be also addressed.

  16. Multi-Wavelength Time Variability of Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Chatterjee, Ritaban

    2009-01-01

    Due to their large distances, AGNs are not spatially resolved with current and near-future technologies except by radio interferometry. However, we can use time variability, one of the defining properties of AGNs, to probe the location and physical processes related to the emission at resolutions even finer than provided by VLBI. I use extensive multi-frequency monitoring data of the blazars 3C 279 and PKS 1510-089 (over 10 years long) and the radio galaxy 3C 120 ( 5 years), including well-sampled light curves (radiative flux vs. time) at X-ray energies (2-10 keV), optical wavelengths (R band), and radio frequencies (14.5 GHz and 37 GHz), as well as monthly images obtained with the Very Long Baseline Array (VLBA) at 43 GHz that follow changes in the emission structure of the jet on parsec scales. I have developed and applied a set of statistical tools to characterize the time variability of AGNs. This includes the power spectral density (PSD) and its uncertainties, discrete cross-correlation functions and their significance using random light curves simulated from the previously calculated PSDs, and decomposition of light curves into individual flares. I also model the time variable emission spectrum of an AGN jet using a numerical code that includes conical geometry, turbulent magnetic field and density, and energization of electrons due to a moving shock front. Comparing the results of the model calculations and the application of the above-mentioned statistical procedures on the real data, I draw conclusions about the location of the emission regions of these objects. I also identify the ongoing emission mechanisms and implications regarding the physics of jets. This work is supported by NASA through grants NNX08AJ64G (ADP) and NNX08AV65G (Fermi).

  17. Multi-wavelength observations of the peculiar red giant HR 3126

    NASA Technical Reports Server (NTRS)

    Pesce, Joseph E.; Stencel, Robert E.; Walter, Frederick M.; Doggett, Jesse; Dachs, Joachim; Whitelock, Patricia A.; Mundt, Reinhard

    1988-01-01

    Ultraviolet observations of the red giant HR 3126 are combined with multi-wavelength data in order to provide a firmer basis for explaining the arc-minute sized nebula surrounding the object. Possibilities as to the location of HR 3126 on the Hertzsprung-Russel diagram, and to the formation mechanisms of the reflection nebula IC 2220 associated with it, are summarized.

  18. Multi-Wavelength Mode-Locked Laser Arrays for WDM Applications

    NASA Technical Reports Server (NTRS)

    Davis, L.; Young, M.; Dougherty, D.; Keo, S.; Muller, R.; Maker, P.

    1998-01-01

    Multi-wavelength arrays of colliding pulse mode-locked (CPM) lasers have been demonstrated for wavelength division multiplexing (WDM) applications. The need for increased bandwidth is driving the development of both increased speed in time division multiplexing (TDM) and more channels in WDM for fiber optic communication systems.

  19. Simultaneous retrieval of aerosol optical thickness and chlorophyll concentration from multi-wavelength measurement over East China Sea

    NASA Astrophysics Data System (ADS)

    Shi, C.; Nakajima, T.; Hashimoto, M.

    2016-12-01

    A flexible inversion algorithm is proposed for simultaneously retrieving aerosol optical thickness (AOT) and surface chlorophyll a (Chl) concentration from multi-wavelength observation over the ocean. In this algorithm, forward radiation calculation is performed by an accurate coupled atmosphere-ocean model with a sophisticated bio-optical ocean module, which is different from those in the classic ocean color algorithms that decouple the atmosphere and ocean systems using atmospheric correction procedures. Then, a full-physical nonlinear optimization approximation approach is used to retrieve AOT and Chl. For AOT retrieval, a global three-dimensional spectral radiation-transport aerosol model is used as the priori constraint to increase the retrieval accuracy of aerosol. To investigate the algorithm's availability, the retrieval experiment is conducted using simulated radiance data to demonstrate that the relative errors in simultaneously determining AOT and Chl can be mostly controlled to within 10% using multi-wavelength and angle coving in and out of sunglint. Furthermore, the inversion results are assessed using the actual satellite observation data obtained from Greenhouse gas Observation SATellite (GOSAT) and MODerate resolution Imaging Spectroradiometer (MODIS)/Aqua instruments through comparison to Aerosol Robotic Network (AERONET) aerosol and ocean color (OC) products over East China Sea. Both the retrieved AOT and Chl compare favorably to the reported AERONET values, particularly when using the CASE 2 ocean module in turbid water, even when the retrieval is performed in the presence of high aerosol loading and sun glint. Finally, the MODIS images are used to jointly retrieve the spatial distribution of AOT and Chl in comparison to the MODIS AOT and OC products.

  20. SIMULTANEOUS MULTI-WAVELENGTH OBSERVATIONS OF Sgr A* DURING 2007 APRIL 1-11

    SciTech Connect

    Yusef-Zadeh, F.; Bushouse, H.; Wardle, M.; Heinke, C.; Roberts, D. A.; Dowell, C. D.; Brunthaler, A.; Reid, M. J.; Martin, C. L.; Marrone, D. P.; Porquet, D.; Grosso, N.; Dodds-Eden, K.; Gillessen, S.; Bower, G. C.; Wiesemeyer, H.; Miyazaki, A.; Pal, S.; Goldwurm, A.

    2009-11-20

    We report the detection of variable emission from Sgr A* in almost all wavelength bands (i.e., centimeter, millimeter, submillimeter, near-IR, and X-rays) during a multi-wavelength observing campaign. Three new moderate flares are detected simultaneously in both near-IR and X-ray bands. The ratio of X-ray to near-IR flux in the flares is consistent with inverse Compton scattering of near-IR photons by submillimeter emitting relativistic particles which follow scaling relations obtained from size measurements of Sgr A*. We also find that the flare statistics in near-IR wavelengths is consistent with the probability of flare emission being inversely proportional to the flux. At millimeter wavelengths, the presence of flare emission at 43 GHz (7 mm) using the Very Long Baseline Array with milliarcsecond spatial resolution indicates the first direct evidence that hourly timescale flares are localized within the inner 30 x 70 Schwarzschild radii of Sgr A*. We also show several cross-correlation plots between near-IR, millimeter, and submillimeter light curves that collectively demonstrate the presence of time delays between the peaks of emission up to 5 hr. The evidence for time delays at millimeter and submillimeter wavelengths are consistent with the source of emission initially being optically thick followed by a transition to an optically thin regime. In particular, there is an intriguing correlation between the optically thin near-IR and X-ray flare and optically thick radio flare at 43 GHz that occurred on 2007 April 4. This would be the first evidence of a radio flare emission at 43 GHz delayed with respect to the near-IR and X-ray flare emission. The time delay measurements support the expansion of hot self-absorbed synchrotron plasma blob and weaken the hot spot model of flare emission. In addition, a simultaneous fit to 43 and 84 GHz light curves, using an adiabatic expansion model of hot plasma, appears to support a power law rather than a relativistic

  1. Quantified H I morphology - I. Multi-wavelength analysis of the THINGS galaxies

    NASA Astrophysics Data System (ADS)

    Holwerda, B. W.; Pirzkal, N.; de Blok, W. J. G.; Bouchard, A.; Blyth, S.-L.; van der Heyden, K. J.; Elson, E. C.

    2011-10-01

    Galaxy evolution is driven to a large extent by interactions and mergers with other galaxies and the gas in galaxies is extremely sensitive to the interactions. One method to measure such interactions uses the quantified morphology of galaxy images. Well-established parameters are Concentration, Asymmetry, Smoothness, Gini and M20 of a galaxy image. Thus far, the application of this technique has mostly been restricted to rest-frame ultraviolet and optical images. However, with the new radio observatories being commissioned [South African Karoo Array Telescope (MeerKAT), Australian SKA Pathfinder (ASKAP), Extended Very Large Array (EVLA), Westerbork Synthesis Radio Telescope/APERture Tile In Focus instrument (WSRT/APERTIF) and ultimately the Square Kilometer Array (SKA)], a new window on the neutral atomic hydrogen gas (H I) morphology of large numbers of galaxies will open up. The quantified morphology of gas discs of spirals can be an alternative indicator of the level and frequency of interaction. The H I in galaxies is typically spatially more extended and more sensitive to low-mass or weak interactions. In this paper, we explore six morphological parameters calculated over the extent of the stellar (optical) disc and the extent of the gas disc for a range of wavelengths spanning ultraviolet (UV), optical, near- and far-infrared and 21 cm (H I) of 28 galaxies from The H I Nearby Galaxy Survey (THINGS). Although the THINGS sample is small and contains only a single ongoing interaction, it spans both non-interacting and post-interacting galaxies with a wealth of multi-wavelength data. We find that the choice of area for the computation of the morphological parameters is less of an issue than the wavelength at which they are measured. The signal of interaction is as good in the H I as at any of the other wavelengths at which morphology has been used to trace the interaction rate to date, mostly star formation dominated ones (near- and far-ultraviolet). The

  2. Athermalization and on-chip multi-wavelength integration of VCSELs employing thermally actuated micromachined mirrors

    NASA Astrophysics Data System (ADS)

    Nakahama, M.; Sakaguchi, T.; Matsutani, A.; Koyama, F.

    2014-09-01

    An athermal multi-wavelength vertical cavity surface emitting laser (VCSEL) array is demonstrated using a thermally actuated cantilever structure with different cantilever lengths. The cavity length of each VCSEL is precisely controlled via the deflection of the cantilever due to difference in the lattice constant of GaAlAs layers. Also, the thermally induced actuation of the cantilever reduces the cavity length as the ambient temperature increases, which compensates the thermal wavelength drift of the VCSEL. The wavelength drift could be reduced within ±0.017 nm/K, which is 4 times smaller than that of conventional VCSELs. The proposed multi-wavelength VCSEL array enables four wavelength channels with 2.5 nm spacing under uncooled operations.

  3. Versatile multi-wavelength ultrafast fiber laser mode-locked by carbon nanotubes

    PubMed Central

    Liu, Xueming; Han, Dongdong; Sun, Zhipei; Zeng, Chao; Lu, Hua; Mao, Dong; Cui, Yudong; Wang, Fengqiu

    2013-01-01

    Multi-wavelength lasers have widespread applications (e.g. fiber telecommunications, pump-probe measurements, terahertz generation). Here, we report a nanotube-mode-locked all-fiber ultrafast oscillator emitting three wavelengths at the central wavelengths of about 1540, 1550, and 1560 nm, which are tunable by stretching fiber Bragg gratings. The output pulse duration is around 6 ps with a spectral width of ~0.5 nm, agreeing well with the numerical simulations. The triple-laser system is controlled precisely and insensitive to environmental perturbations with <0.04% amplitude fluctuation. Our method provides a simple, stable, low-cost, multi-wavelength ultrafast-pulsed source for spectroscopy, biomedical research and telecommunications. PMID:24056500

  4. Multi-wavelength Raman spectroscopy study of supported vanadia catalysts: Structure identification and quantification

    DOE PAGES

    Wu, Zili

    2014-10-20

    Revealing the structure of supported metal oxide catalysts is a prerequisite for establishing the structure - catalysis relationship. Among a variety of characterization techniques, multi-wavelength Raman spectroscopy, combining resonance Raman and non-resonance Raman with different excitation wavelengths, has recently emerged as a particularly powerful tool in not only identifying but also quantifying the structure of supported metal oxide clusters. In our review, we make use of two supported vanadia systems, VOx/SiO2 and VOx/CeO2, as examples to showcase how one can employ this technique to investigate the heterogeneous structure of active oxide clusters and to understand the complex interaction between themore » oxide clusters and the support. Moreover, the qualitative and quantitative structural information gained from the multi-wavelength Raman spectroscopy can be utilized to provide fundamental insights for designing more efficient supported metal oxide catalysts.« less

  5. Multi-wavelength Raman spectroscopy study of supported vanadia catalysts: Structure identification and quantification

    SciTech Connect

    Wu, Zili

    2014-10-20

    Revealing the structure of supported metal oxide catalysts is a prerequisite for establishing the structure - catalysis relationship. Among a variety of characterization techniques, multi-wavelength Raman spectroscopy, combining resonance Raman and non-resonance Raman with different excitation wavelengths, has recently emerged as a particularly powerful tool in not only identifying but also quantifying the structure of supported metal oxide clusters. In our review, we make use of two supported vanadia systems, VOx/SiO2 and VOx/CeO2, as examples to showcase how one can employ this technique to investigate the heterogeneous structure of active oxide clusters and to understand the complex interaction between the oxide clusters and the support. Moreover, the qualitative and quantitative structural information gained from the multi-wavelength Raman spectroscopy can be utilized to provide fundamental insights for designing more efficient supported metal oxide catalysts.

  6. Multi-wavelength observations of PSR B1259-63 during the 2014 periastron passage

    NASA Astrophysics Data System (ADS)

    van Soelen, B.; Armstrong, R. P.; Väisänen, P.; Sushch, I.; Odendaal, A.; Meintjes, P. J.

    The gamma-ray binary star system PSR B1259-63 is unique among the five known systems since it is the only one where a radio pulsar has been directly detected. Close to periastron the system produces non-thermal/unpulsed emission from radio to TeV gamma-ray energies. In 2010 Fermi/LAT detected a rapid increase and peak emission at ˜30 days after periastron, at a time when emission at other wavelengths was already decreasing. PSR B1259-63 will go through periastron again on 2014 May 4. We have proposed to use the Southern African Large Telescope and the KAT-7 radio telescope array in order to contribute to the multi-wavelength coverage of the system. An outline of this proposed multi-wavelength campaign is presented.

  7. Novel multi wavelength sensor concept to detect total hemoglobin concentration, methemoglobin and oxygen saturation

    NASA Astrophysics Data System (ADS)

    Timm, Ulrich; Gewiss, Helge; Kraitl, Jens; Stuepmann, Kirstin; Hinz, Michael; Koball, Sebastian; Ewald, Hartmut

    2015-03-01

    The paper will describe the novel multi-wavelength photometric device OxyTrue Hb® which is capable to measure the hemoglobin (Hb) and methemoglobin (MetHb) concentration non-invasively. Clinic trails in blood donation centers and during the dialysis are done to prove and demonstrate the performance of the system. The results are compared to the gold standard, the BGA measurement.

  8. Focus detection criterion for refocusing in multi-wavelength digital holography.

    PubMed

    Xu, Li; Mater, Mike; Ni, Jun

    2011-08-01

    The majority of focus detection criteria reported is based on amplitude contrast. Due to phase wrapping, phase contrast was previously reported unsuitable for focus finding tasks. By taking the advantage of multi-wavelength digital holography, we propose a new focus detection criterion based on phase contrast. Experimental results are presented to prove the feasibility of the developed criterion. Possible applications of the developed technology include inspecting machined surfaces in the auto industry.

  9. Multi-Wavelength Optical Code-Division-Multiplexing Based on Passive, Linear, Unitary Filters

    DTIC Science & Technology

    2007-11-02

    EG) Prescribed by ANSI Std. 238.18 Designed using Perform Pro, WHS/DIOR, Oct 94 Multi-Wavelength Optical Code-Division-Multiplexing Based on... FTTH ) and fiber to the desk (FTTD) a reality. Every hertz of bandwidth available in optical fiber is now valuable for carrying data traffic in...contemporary communication systems. A different paradigm is required in designing multiple access optical communication systems to meet the challenges in

  10. A New Multi-Wavelength Synoptic Network for Solar Physics and Space Weather

    NASA Astrophysics Data System (ADS)

    Hill, Frank; Roth, Markus; Thompson, Michael

    2013-04-01

    Continuous solar observations are important for many research topics in solar physics, such as magnetic field evolution, flare and CME characteristics, and p-mode oscillation measurements. In addition, space weather operations require constant streams of solar data as input. The deployment of a number of identical instruments around the world in a network has proven to be a very effective strategy for obtaining nearly continuous solar observations. The financial costs of a network are 1-2 orders of magnitude lower than space-based platforms; network instrumentation can be easily accessed for maintenance and upgrades; and telemetry bandwidth is readily available. Currently, there are two solar observing networks with consistent instruments: BiSON and GONG, both designed primarily for helioseismology. In addition, GONG has been augmented with continual magnetic field measurements and H-alpha imagery, with both being used for space weather operational purposes. However, GONG is now 18 years old and getting increasingly more challenging to maintain. There are also at least three scientific motivations for a multi-wavelength network: Recent advances in helioseismology have demonstrated the need for multi-wavelength observations to allow more accurate interpretation of the structure and dynamics below sunspots. Vector magnetometry would greatly benefit from multi-wavelength observations to provide height information and resolve the azimuthal ambiguity. Finally, space weather operations always need a consistent reliable source of continual solar data. This presentation will outline the scientific need for a multi-wavelength network, and discuss some concepts for the design of the instrumentation. A workshop on the topic will be held in Boulder this April.

  11. Multi-Wavelength Observations of 3C 273 in 1993-1995

    NASA Technical Reports Server (NTRS)

    vonMontigny, C.; Aller, H.; Aller, M.; Bruhweiler, F.; Collmar, W.; Courvoisier, T. J.-L.; Edwards, P. G.; Fichtel, C. E.; Fruscione, A.; Ghisellini, G.

    1997-01-01

    We present the results of the multi-wavelength campaigns on 3C 273 in 1993-1995. During the observations in late 1993 this quasar showed an increase of its flux for energies >= 100 MeV from about 2.1 x 10(exp -7) photons/sq cm.s to approximately 5.6 x 10(exp -7) photons/sq cm.s during a radio outburst at 14.5, 22 and 37 GHz. However, no one-to-one correlation of the gamma-ray radiation with any frequency could be found. The photon spectral index of the high energy spectrum changed from GAMMA(sub gamma) = (3.20 +/- 0.54) to GAMMA(sub gamma) = (2.20 +/- 0.22) in the sense that the spectrum flattened when the gamma-ray flux increased. Fits of the three most prominent models (synchrotron self-Comptonization, external inverse Comptonization and the proton initiated cascade model) for the explanation of the high gamma-ray emission of active galactic nuclei were performed to the multi-wavelength spectrum of 3C 273 . All three models are able to represent the basic features of the multi-wavelength spectrum. Although there are some differences the data are still not decisive enough to discriminate between the models.

  12. Multi-wavelength coherent transmission using an optical frequency comb as a local oscillator.

    PubMed

    Kemal, Juned N; Pfeifle, Joerg; Marin-Palomo, Pablo; Pascual, M Deseada Gutierrez; Wolf, Stefan; Smyth, Frank; Freude, Wolfgang; Koos, Christian

    2016-10-31

    Steadily increasing data rates of optical interfaces require spectrally efficient coherent transmission using higher-order modulation formats in combination with scalable wavelength-division multiplexing (WDM) schemes. At the transmitter, optical frequency combs (OFC) lend themselves to particularly precise multi-wavelength sources for WDM transmission. In this work we demonstrate that these advantages can also be leveraged at the receiver by using an OFC as a highly scalable multi-wavelength local oscillator (LO) for coherent detection. In our experiments, we use a pair of OFC that rely on gain switching of injection-locked semiconductor lasers both for WDM transmission and intradyne reception. We synchronize the center frequency and the free spectral range of the receiver comb to the transmitter, keeping the intradyne frequencies for all data channels below 15 MHz. Using 13 WDM channels, we transmit an aggregate line rate (net data rate) of 1.104 Tbit/s (1.032 Tbit/s) over a 10 km long standard single mode fiber at a spectral efficiency of 5.16 bit/s/Hz. To the best of our knowledge, this is the first demonstration of coherent WDM transmission using synchronized frequency combs as light source at the transmitter and as multi-wavelength LO at the receiver.

  13. HELP: The Herschel Extragalactic Legacy Project and The Coming of Age of Multi-wavelength Astrophysics

    NASA Astrophysics Data System (ADS)

    Vaccari, M.

    How did galaxies form and evolve? This is one of the most challenging questions in astronomy today. Answering it requires a careful combination of observational and theoretical work to reliably determine the observed properties of cosmic bodies over large portions of the distant Universe on the one hand, and accurately model the physical processes driving their evolution on the other. Most importantly, it requires bringing together disparate multi-wavelength and multi-resolution spectro-photometric datasets in an homogeneous and well-characterized manner so that they are suitable for a rigorous statistical analysis. The Herschel Extragalactic Legacy Project (HELP) funded by the EC FP7 SPACE program aims to achieve this goal by combining the expertise of optical, infrared and radio astronomers to provide a multi-wavelength database for the distant Universe as an accessible value-added resource for the astronomical community. It will do so by bringing together multi-wavelength datasets covering the 1,000 deg2 mapped by Herschel extragalactic surveys in an homogeneous and well-characterized manner, creating a joint lasting legacy from several ambitious sky surveys.

  14. Spatial and compositional dependence of deep-level defects in InGaN LEDs (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Armstrong, Andrew M.; Crawford, Mary H.; Koleske, Daniel D.; Nelson, Erik C.; Wildeson, Isaac; Deb, Parijat

    2017-02-01

    Efficiency droop and the green gap are challenges to InGaN/GaN light emitting diodes (LEDs). Defects have been suggested to contribute to both effects, so understanding the origin of defects and their impact on LED performance is important to improving efficiency. This talk describes the use of deep level optical spectroscopy (DLOS) to characterize deep level defects in quantum well (QW) and quantum barrier (QB) regions of InGaN LEDs. The spatial dependence of deep level defect density in the MQW region and the evolution of QW deep level defects with indium alloying will be discussed.

  15. First-Light Galaxies or Intrahalo Stars: Multi-Wavelength Measurements of the Infrared Background Anisotropies

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha

    The research program described in this proposal can be broadly described as data analysis, measurement, and interpretation of the spatial fluctuations of the unresolved cosmic IR background. We will focus primarily on the background at optical and near-IR wavelengths as probed by Hubble and Spitzer. As absolute background intensity measurements are challenging, the focus is on the spatial fluctuations similar to the anisotropiesof the cosmic microwave background (CMB). Measurements of the unresolved Spitzer fluctuations by two independent teams on multiple fields agree within the measurement errors. However, there are now two interpretations on the origin of the unresolved IRAC fluctuations. One involves a population of faint sources at very high redshifts (z > 6) during the epoch of reionization. The second interpretation involves the integrated emission from intrahalo light associated with diffuse stars in the outskirts of z of 1 to 3 dark matter halos of galaxies. We now propose to further test these two interpretations with a new set of measurements at shorter IR and optical wavelengths with HST/ACS and WFC3 overlapping with deep IRAC surveys. A multi-wavelength study from 0.5 to 4.5 micron will allow us to independently determine the relative contribution of intrahalo light and z > 8 faint galaxies to the unresolved IR fluctuations. We will also place strong limits on the surface density of faint sources at z > 8. Such a limit will be useful for planning deep surveys with JWST. Moving to the recent wide IRAC fields with the warm mission, we propose to study fluctuations at tens of degree angular scales. At such large angular scales IRAC fluctuations should trace diffuse Galactic light (DGL), ISM dust-scattered starlight in our Galaxy. We will measure the amplitude and slope of the DGL power spectrum and compare them to measurements of the Galactic dust power spectrum from IRAS and Planck and study if the large degree-scale fluctuations seen in CIBER can be

  16. Generation of tunable multi-wavelength EDFL by using graphene thin film as nonlinear medium and stabilizer

    NASA Astrophysics Data System (ADS)

    Ahmad, Harith; Hassan, Nor Ahya; Aidit, Siti Nabila; Tiu, Zian Cheak

    2016-07-01

    The applications of graphene thin film as a nonlinear medium and stabilizer to generate a stable multi-wavelength is proposed and demonstrated. A 50 m long highly nonlinear photonic crystal fiber (PCF) is incorporated into the cavity to achieve unstable multi-wavelength based on nonlinear polarization rotation (NPR) effect. By introducing the graphene thin film into the cavity, a stable multi-wavelength oscillation is obtained. The laser generates more than 7 lasings with constant spacing of 0.47 nm. The output is highly stable with power fluctuation of less than 3 dB within a period of 30 min. The multi-wavelength EDFL exhibits a tunability from the center wavelength of 1550 nm to 1560 nm.

  17. Multi-wavelength fiber ring laser based on a sampled chirped fiber Bragg grating with a hybrid gain medium

    NASA Astrophysics Data System (ADS)

    Moon, Dae Seung; Chung, Youngjoo

    2012-04-01

    The novel multi-wavelength fiber ring laser based on a sampled chirped fiber Bragg grating with a single SOA or a hybrid gain medium is demonstrated, respectively. In case of a hybrid gain medium, the SMSR improvement of ~ 5 dB was obtained when compared with the system with a single SOA. The proposed fiber laser offers advantages such as simple structure, low loss, multi-wavelength lasing lines with moderate output power.

  18. Multi-Wavelength Observations of the Supernova Remnant Populations in the Nearby Spiral Galaxies IC 342 and NGC 4258

    NASA Astrophysics Data System (ADS)

    Pannuti, Thomas; Chomiuk, L.; Grimes, C. K.; Staggs, W. D.; Tussey, J. M.; Laine, S.; Schlegel, E.

    2011-01-01

    Supernova remnants (SNRs) are intimately tied to many crucial processes associated with the interstellar medium of galaxies, such as the acceleration of cosmic-ray particles and the deposition of vast amounts of kinetic energy and chemically-enriched material. Well-known observational challenges in the study of SNRs located in the Milky Way Galaxy (for example, formidable extinction along Galactic lines of sight and considerable uncertainties in the distances to these sources) have motivated searches for SNRs in nearby galaxies at such characteristic wavelengths as X-ray, optical and radio. These searches have revealed a considerable number of SNRs and led to new insights into their properties, but the SNR populations in only a handful of nearby galaxies have been adequately surveyed at multiple wavelengths. To help remedy this situation, we are conducting a multi-wavelength study of the SNR population of selected nearby galaxies. To illustrate our work, we present the results of studies of the SNR population in two nearby spiral galaxies, IC 342 and NGC 4258. Our results draw upon the analysis of pointed archival radio and X-ray observations of these two galaxies. Initial results will be presented and discussed.

  19. The faint radio source population at 15.7 GHz - II. Multi-wavelength properties

    NASA Astrophysics Data System (ADS)

    Whittam, I. H.; Riley, J. M.; Green, D. A.; Jarvis, M. J.; Vaccari, M.

    2015-11-01

    A complete, flux density limited sample of 96 faint (>0.5 mJy) radio sources is selected from the 10C survey at 15.7 GHz in the Lockman Hole. We have matched this sample to a range of multi-wavelength catalogues, including Spitzer Extragalactic Representative Volume Survey, Spitzer Wide-area Infrared Extragalactic survey, United Kingdom Infrared Telescope Infrared Deep Sky Survey and optical data; multi-wavelength counterparts are found for 80 of the 96 sources and spectroscopic redshifts are available for 24 sources. Photometric redshifts are estimated for the sources with multi-wavelength data available; the median redshift of the sample is 0.91 with an interquartile range of 0.84. Radio-to-optical ratios show that at least 94 per cent of the sample are radio loud, indicating that the 10C sample is dominated by radio galaxies. This is in contrast to samples selected at lower frequencies, where radio-quiet AGN and star-forming galaxies are present in significant numbers at these flux density levels. All six radio-quiet sources have rising radio spectra, suggesting that they are dominated by AGN emission. These results confirm the conclusions of Paper I that the faint, flat-spectrum sources which are found to dominate the 10C sample below ˜1 mJy are the cores of radio galaxies. The properties of the 10C sample are compared to the Square Kilometre Array Design Studies Simulated Skies; a population of low-redshift star-forming galaxies predicted by the simulation is not found in the observed sample.

  20. Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

    SciTech Connect

    Ni, P. A.; More, R. M.; Bieniosek, F. M.

    2013-08-04

    Abstract This paper examines the reliability of a widely used method for temperature determination by multi-wavelength pyrometry. In recent WDM experiments with ion-beam heated metal foils, we found that the statistical quality of the fit to the measured data is not necessarily a measure of the accuracy of the inferred temperature. We found a specific example where a second-best fit leads to a more realistic temperature value. The physics issue is the wavelength-dependent emissivity of the hot surface. We discuss improvements of the multi-frequency pyrometry technique, which will give a more reliable determination of the temperature from emission data.

  1. Gamma-Ray Bursts and Fast Transients. Multi-wavelength Observations and Multi-messenger Signals

    NASA Astrophysics Data System (ADS)

    Willingale, R.; Mészáros, P.

    2017-07-01

    The current status of observations and theoretical models of gamma-ray bursts and some other related transients, including ultra-long bursts and tidal disruption events, is reviewed. We consider the impact of multi-wavelength data on the formulation and development of theoretical models for the prompt and afterglow emission including the standard fireball model utilizing internal shocks and external shocks, photospheric emission, the role of the magnetic field and hadronic processes. In addition, we discuss some of the prospects for non-photonic multi-messenger detection and for future instrumentation, and comment on some of the outstanding issues in the field.

  2. Stable multi-wavelength fiber lasers for temperature measurements using an optical loop mirror.

    PubMed

    Diaz, Silvia; Socorro, Abian Bentor; Martínez Manuel, Rodolfo; Fernandez, Ruben; Monasterio, Ioseba

    2016-10-10

    In this work, two novel stable multi-wavelength fiber laser configurations are proposed and demonstrated by using a spool of a single-mode fiber as an optical loop mirror and one or two fiber ring cavities, respectively. The lasers are comprised of fiber Bragg grating reflectors as the oscillation wavelength selecting filters. The influence of the length of the spool of fiber on the laser stability both in terms of wavelength and laser output power was investigated. An application for temperature measurement is also shown.

  3. Multi-wavelength laser generation with Bismuthbased Erbium-doped fiber.

    PubMed

    Ahmad, H; Shahi, S; Harun, S W

    2009-01-05

    A multi-wavelength laser comb is demonstrated using a nonlinear effect in a backward pumped Bismuth-based Erbium-doped fiber (Bi-EDF) for the first time. It uses a ring cavity resonator scheme containing a 215 cm long highly nonlinear Bi-EDF, optical isolators, polarisation controller and 10 dB output coupler. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41 nm at 1615.5 nm region using 146 mW of 1480 nm pump power.

  4. Influence of color coatings on aircraft surface ice detection based on multi-wavelength imaging

    NASA Astrophysics Data System (ADS)

    Zhuge, Jing-chang; Yu, Zhi-jing; Gao, Jian-shu; Zheng, Da-chuan

    2016-03-01

    In this paper, a simple aircraft surface ice detection system is proposed based on multi-wavelength imaging. Its feasibility is proved by the experimental results. The influence of color coatings of aircraft surface is investigated. The results show that the ice area can be clearly distinguished from the red, white, gray and blue coatings painted aluminum plates. Due to the strong absorption, not enough signals can be detected for the black coatings. Thus, a deep research is needed. Even though, the results of this paper are helpful to the development of aircraft surface ice detection.

  5. Multi-wavelength generation based on cascaded Raman scattering and self-frequency-doubling in KTA

    NASA Astrophysics Data System (ADS)

    Zhong, K.; Li, J. S.; Xu, D. G.; Ding, X.; Zhou, R.; Wen, W. Q.; Li, Z. Y.; Xu, X. Y.; Wang, P.; Yao, J. Q.

    2010-04-01

    A multi-wavelength laser is developed based on cascaded stimulated Raman scattering (SRS) and self-frequency-doubling in an x-cut KTA crystal pumped by an A-O Q-switched Nd:YAG laser. The generation of 1178 nm from cascaded SRS of 234 and 671 cm-1 Raman modes is observed. The six wavelengths, including the fundamental 1064 nm, four Stokes waves at 1091, 1120, 1146, 1178 nm, and the second harmonic generation (SHG) of 1146 nm, are tens to hundreds of millwatts for each at 10 kHz, corresponding to a total conversion efficiency of 8.72%.

  6. A multi-wavelength LIDAR system based on an erbium-doped fiber MOPA-system

    NASA Astrophysics Data System (ADS)

    Töws, Albert; Kurtz, Alfred

    2014-10-01

    A multi-wavelength fiber based MOPA-system is proposed to increase performance of coherent Doppler lidar systems. The setup of the four-wavelength lidar system is described and characterized. We show that the speckle patterns of each wavelength are uncorrelated. The measured Goodman's M-parameter is 3.8 for four wavelengths, using hard target reflections. Atmospheric measurements show uncorrelated speckle patterns as well. Consequently, the precision of the measured wind velocity can be improved by a factor of two.

  7. SOA-based multi-wavelength laser using fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Sulaiman, A. H.; Shahi, S.; Harun, S. W.

    2009-05-01

    We propose and experimentally demonstrate a triple-wavelength fiber ring laser using a semiconductor optical amplifier (SOA) in conjunction with a series of fiber Bragg gratings (FBGs). The three channels operate at 1554.4, 1555.3, and 1556.1 nm with a peak power above -25 dBm and optical signal-to-noise (OSNR) above 30 dB at SOA drive current of 350 mA under the room temperature. The proposed laser configuration has the advantages of a simple and compact structure, multi-wavelength operation and the system can be upgraded to generate more wavelengths by increasing the number of FBG used.

  8. Novel multi wavelength sensor concept to measure carboxy- and methemoglobin concentration non-invasively

    NASA Astrophysics Data System (ADS)

    Timm, Ulrich; Kraitl, Jens; Gewiss, Helge; Kamysek, Svend; Brock, Beate; Ewald, Hartmut

    2016-03-01

    This paper will describe a novel multi-wavelength photometric method to measure carboxyhemoglobin (COHb) and methemoglobin (MetHb) concentration non-invasively. COHb and MetHb are so called dysfunctional hemoglobin derivatives and they are not able to carry oxygen. Standard pulse oximeters are only able to measure two derivatives, namely oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) but the presence of other derivatives in the blood may distort the readings. The paper presents a new approach of a noninvasive sensor system to measure COHb and MetHb and the validation in vivo and in vitro.

  9. Integrated 10 Gb/s AWG-based correlator for multi-wavelength optical header recognition.

    PubMed

    Aljada, Muhsen; Alameh, Kamal E

    2008-03-31

    In this paper we experimentally demonstrate a novel optical correlator employing dual integrated Arrayed Waveguide Grating (AWG) in conjunction with variable delay lines. The variable delay lines provide wavelength-dependent time delays and generate a wavelength profile that matches arbitrary bit patterns, whereas the AWGs are used to demultiplex and multiplex the wavelength components of the multi-wavelength header bit pattern. The recognition of 4-bit optical patterns at different wavelengths is experimentally demonstrated at 10 Gb/s by showing that the correlator produces an autocorrelation waveform of high peak whenever the input bit pattern matches the wavelengths profile, and a low-amplitude cross-correlation function otherwise.

  10. Multi-wavelength erbium-doped fiber laser based on random distributed feedback

    NASA Astrophysics Data System (ADS)

    Liu, Yuanyang; Dong, Xinyong; Jiang, Meng; Yu, Xia; Shum, Ping

    2016-09-01

    We experimentally demonstrated a multi-wavelength erbium-doped fiber laser based on random distributed feedback via a 20-km-long single-mode fiber together with a Sagnac loop mirror. The number of channels can be modulated from 2 to 8 at room temperature when the pump power is changed from 30 to 180 mW, indicating that wavelength competition caused by homogenous gain broadening of erbium-doped fiber is significantly suppressed. Other advantages of the laser include low cost, low-threshold pump power and simple fabrication.

  11. Linear FBG Temperature Sensor Interrogation with Fabry-Perot ITU Multi-wavelength Reference

    PubMed Central

    Park, Hyoung-Jun; Song, Minho

    2008-01-01

    The equidistantly spaced multi-passbands of a Fabry-Perot ITU filter are used as an efficient multi-wavelength reference for fiber Bragg grating sensor demodulation. To compensate for the nonlinear wavelength tuning effect in the FBG sensor demodulator, a polynomial fitting algorithm was applied to the temporal peaks of the wavelength-scanned ITU filter. The fitted wavelength values are assigned to the peak locations of the FBG sensor reflections, obtaining constant accuracy, regardless of the wavelength scan range and frequency. A linearity error of about 0.18% against a reference thermocouple thermometer was obtained with the suggested method. PMID:27873898

  12. Optical links for detector instrumentation: on-detector multi-wavelength silicon photonic transmitters

    NASA Astrophysics Data System (ADS)

    Karnick, D.; Skwierawski, P.; Schneider, M.; Eisenblätter, L.; Weber, M.

    2017-03-01

    We report on our recent progress in developing an optical transmission system based on wavelength division multiplexing (WDM) to enhance the read-out data rate of future particle detectors. The design and experimental results of the prototype of a monolithically integrated multi-wavelength transmitter are presented as well as temperature studies of electro-optic modulators. Furthermore, we show the successful permanent coupling of optical fibers to photonic chips, which is an essential step towards packaging of the opto-electronic components.

  13. Switchable multi-wavelength Tm-doped mode-locked fiber laser.

    PubMed

    Yan, Zhiyu; Tang, Yulong; Sun, Biao; Liu, Tao; Li, Xiaohui; Ping, Perry Shum; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2015-05-01

    We propose and demonstrate for the first time a switchable tri-wavelength Tm-doped ultra-fast fiber laser based on nonlinear polarization evolution (NPE) technique. The NPE effect induces wavelength-dependent loss in the cavity that changes the homogeneous broadening of the effective gain to become inhomogeneous. This inhomogeneous effective gain spectral profile enables the multi-wavelength mode locking. Binary control of three bits can be realized by controlling the polarization in the compact fiber ring cavity. Such switchable laser has potential applications in optical signal processing and communication.

  14. Linear FBG Temperature Sensor Interrogation with Fabry-Perot ITU Multi-wavelength Reference.

    PubMed

    Park, Hyoung-Jun; Song, Minho

    2008-10-29

    The equidistantly spaced multi-passbands of a Fabry-Perot ITU filter are used as an efficient multi-wavelength reference for fiber Bragg grating sensor demodulation. To compensate for the nonlinear wavelength tuning effect in the FBG sensor demodulator, a polynomial fitting algorithm was applied to the temporal peaks of the wavelength-scanned ITU filter. The fitted wavelength values are assigned to the peak locations of the FBG sensor reflections, obtaining constant accuracy, regardless of the wavelength scan range and frequency. A linearity error of about 0.18% against a reference thermocouple thermometer was obtained with the suggested method.

  15. Stable C-band fiber laser with switchable multi-wavelength output using coupled microfiber Mach-Zehnder interferometer

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Jasim, A. A.

    2017-07-01

    A compact coupled microfiber Mach-Zehnder interferometer (CM-MZI) is proposed and experimentally demonstrated for C-band region multi-wavelength tuning and switching in a fiber laser. The CM-MZI is fabricated using a 9 μm single tapered silica optical microfiber fabricated by flame-drawing technique and exploits multi-mode interference to produce spatial mode beating and suppress mode competition of the homogeneous gain medium. The output wavelength spacing is immune to changes in the external environment, but can be changed from 1.5 nm to 1.4 nm by slightly modifying the path-length difference of the CM-MZI. The proposed laser is capable of generating single, dual, triple, quintuple, and sextuple stabilize wavelengths outputs over a range of more than 32 nm using polarization rotation (PR) and macro-bending. The lasers having a 3 dB line-width of less than ∼30 pm and peak-to-floor of about 55 dB at a pump power of 38 mW.

  16. Multi-wavelength Observations of Photospheric Vortex Flows in the Photosphere Using Ground-based and Space-borne Telescopes

    NASA Astrophysics Data System (ADS)

    Palacios, J.; Vargas Domínguez, S.; Balmaceda, L. A.; Cabello, I.; Domingo, V.

    2016-04-01

    In this work we follow a series of papers on high-resolution observations of small-scale structures in the solar atmosphere (Balmaceda et al. 2009, 2010; Vargas Domínguez et al. 2011; Palacios et al. 2012; Domingo et al. 2012; Vargas Domínguez et al. 2015, Cabello et al., in prep), combining several multi-wavelength data series. These were acquired by both ground-based (SST) and space-borne (Hinode) instruments during the joint campaign of the Hinode Operation Program 14, in September 2007. Diffraction-limited SST data were taken in the G-band and G-cont, and were restored by the MFBD technique. Hinode instruments, on the other hand, provided multispectral data from SOT-FG in the CN band, and Mg I and Ca II lines, as well as from SOT-SP in the Fe I line. In this series of works we have thoroughly studied vortex flows and their statistical occurrences, horizontal velocity fields by means of Local Correlation Tracking (LCT), divergence and vorticity. Taking advantage of the high-cadence and high spatial resolution data, we have also studied bright point statistics and magnetic field intensification, highlighting the importance of the smallest-scale magnetic element observations.

  17. Optical modeling with precise spatial-chromatic light distribution in phosphor-converted white LEDs

    NASA Astrophysics Data System (ADS)

    Sun, Ching-Cherng; Chang, Yu-Yu; Wang, Yu-Huan; Chen, Ching-Yi; Lo, Yi-Chien; Cheng, Han-Hsiang

    2015-09-01

    White light LEDs become more and more important in display and lighting in various structures. Here a new modeling algorithm for phosphor-converted white light-emitting diodes (pcW-LEDs) is proposed, aiming to perform accurate simulation for color appearance, where potentially enabling optical designers to remove yellowish/bluish spots in LED lighting. The proposed modeling method is applied to simulate a pcW-LED with a hemi spherical lens. The simulation accurately predicts the blue and yellow light distribution. The model is further verified by applying a total internal reflector lens to the pcW-LED. In the midfield region, the blue and yellow light distribution exhibit large variations as the observation distance changed; this varying light pattern for both the blue and yellow lights can be accurately predicted by using the proposed model. The well-established optical model should facilitate designing a pcW-LED that features high-quality illumination and enhances color uniformity.

  18. MODELING MULTI-WAVELENGTH STELLAR ASTROMETRY. I. SIM LITE OBSERVATIONS OF INTERACTING BINARIES

    SciTech Connect

    Coughlin, Jeffrey L.; Harrison, Thomas E.; Gelino, Dawn M.; Ciardi, David R.; Hoard, D. W.; Wachter, Stefanie; Benedict, G. Fritz; McArthur, Barbara E.; Howell, Steve B.

    2010-07-10

    Interacting binaries (IBs) consist of a secondary star that fills or is very close to filling its Roche lobe, resulting in accretion onto the primary star, which is often, but not always, a compact object. In many cases, the primary star, secondary star, and the accretion disk can all be significant sources of luminosity. SIM Lite will only measure the photocenter of an astrometric target, and thus determining the true astrometric orbits of such systems will be difficult. We have modified the Eclipsing Light Curve code to allow us to model the flux-weighted reflex motions of IBs, in a code we call REFLUX. This code gives us sufficient flexibility to investigate nearly every configuration of IB. We find that SIM Lite will be able to determine astrometric orbits for all sufficiently bright IBs where the primary or secondary star dominates the luminosity. For systems where there are multiple components that comprise the spectrum in the optical bandpass accessible to SIM Lite, we find it is possible to obtain absolute masses for both components, although multi-wavelength photometry will be required to disentangle the multiple components. In all cases, SIM Lite will at least yield accurate inclinations and provide valuable information that will allow us to begin to understand the complex evolution of mass-transferring binaries. It is critical that SIM Lite maintains a multi-wavelength capability to allow for the proper deconvolution of the astrometric orbits in multi-component systems.

  19. Demonstration of Aerosol Property Profiling by Multi-wavelength Lidar Under Varying Relative Humidity Conditions

    NASA Technical Reports Server (NTRS)

    Whiteman, D.N.; Veselovskii, I.; Kolgotin, A.; Korenskii, M.; Andrews, E.

    2008-01-01

    The feasibility of using a multi-wavelength Mie-Raman lidar based on a tripled Nd:YAG laser for profiling aerosol physical parameters in the planetary boundary layer (PBL) under varying conditions of relative humidity (RH) is studied. The lidar quantifies three aerosol backscattering and two extinction coefficients and from these optical data the particle parameters such as concentration, size and complex refractive index are retrieved through inversion with regularization. The column-integrated, lidar-derived parameters are compared with results from the AERONET sun photometer. The lidar and sun photometer agree well in the characterization of the fine mode parameters, however the lidar shows less sensitivity to coarse mode. The lidar results reveal a strong dependence of particle properties on RH. The height regions with enhanced RH are characterized by an increase of backscattering and extinction coefficient and a decrease in the Angstrom exponent coinciding with an increase in the particle size. We present data selection techniques useful for selecting cases that can support the calculation of hygroscopic growth parameters using lidar. Hygroscopic growth factors calculated using these techniques agree with expectations despite the lack of co-located radiosonde data. Despite this limitation, the results demonstrate the potential of multi-wavelength Raman lidar technique for study of aerosol humidification process.

  20. Multi-wavelength studies of the statistical properties of active galaxies using Big Data

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Abrahamyan, H. V.; Gyulzadyan, M. V.; Mikayelyan, G. A.; Paronyan, G. M.

    2017-06-01

    Statistical studies of active galaxies (both AGN and Starburst) using large multi-wavelength data are presented, including new studies of Markarian galaxies, large sample of IR galaxies, variable radio sources, and large homogeneous sample of X-ray selected AGN. Markarian survey (the First Byurakan Survey) was digitized and the DFBS database was created, as the biggest spectroscopic database by the number of objects involved ( ~ 20 million). This database provides both 2D images and 1D spectra. We have carried out a number of projects aimed at revealing and multi-wavelength studies of active galaxies among optical, X-ray, IR and radio sources. Thousands of X-ray sources were identified from ROSAT, including many AGN (52% among all identified sources). IRAS PSC/FSC sources were studied having accurate positions from WISE and a large extragalactic sample was created for further search for AGNs. The fraction of active galaxies among IR-selected galaxies was estimated as 24%. Variable radio sources at 1.4 GHz were revealed by cross-correlation of NVSS and FIRST catalogues using the method introduced by us for optical variability. Radio-X-ray sources were revealed from NVSS and ROSAT for detection of new active galaxies. Big Data in astronomy is described that provide new possibilities for statistical research of active galaxies and other objects.

  1. Optical arbitrary waveform generation based on multi-wavelength semiconductor fiber ring laser

    NASA Astrophysics Data System (ADS)

    Li, Peili; Ma, Xiaolu; Shi, Weihua; Xu, Enming

    2017-09-01

    A new scheme of generating optical arbitrary waveforms based on multi-wavelength semiconductor fiber ring laser (SFRL) is proposed. In this novel scheme, a wide and flat optical frequency comb (OFC) is provided directly by multi-wavelength SFRL, whose central frequency and comb spacing are tunable. OFC generation, de-multiplexing, amplitude and phase modulation, and multiplexing are implementing in an intensity and phase tunable comb filter, as induces the merits of high spectral coherence, satisfactory waveform control and low system loss. By using the mode couple theory and the transfer matrix method, the theoretical model of the scheme is established. The impacts of amplitude control, phase control, number of spectral line, and injection current of semiconductor optical amplifier (SOA) on the waveform similarity are studied using the theoretical model. The results show that, amplitude control and phase control error should be smaller than 1% and 0.64% respectively to achieve high similarity. The similarity of the waveform is improved with the increase of the number of spectral line. When the injection current of SOA is in a certain range, the optical arbitrary waveform reaches a high similarity.

  2. Sub-picometer multi-wavelength detector based on highly sensitive nanomechanical resonator

    NASA Astrophysics Data System (ADS)

    Maeda, Etsuo; Kometani, Reo

    2017-07-01

    The wavelength division multiplexing (WDM) method for near infrared (NIR) optical fiber (1530-1565 nm) is the system that is wildly used for intercontinental communication. WDM achieves high-speed and large-capacity communication, but costs a lot because the high-resolution (˜10 pm) wavelength locker for wavelength stabilization only corresponds to a single wavelength. In this report, we propose a highly sensitive sub-picometer multi-wavelength detector that substitutes a typical single-wavelength detector for WDM. Our wavelength detector consists of a narrow band (FWHM < 10 nm) photonic absorber with an aligned gold nano-fin array on a high-Q (Q-factor > 20 000) nanomechanical resonator. The photonic absorber confines and transforms the illuminated NIR light wave into thermal stress, and then, the thermal stress in the nanomechanical resonator will appear as the eigenfrequency shift of the nanomechanical resonator. Through experimental works with an NIR laser and optical Doppler vibration meter, the sensitivity of our wavelength detector was determined to be 0.196 pm in the 10-nm-range of the NIR region. Our sub-picometer multi-wavelength detector will achieve a fast, wide-band, and cost-effective optical communication system.

  3. MODELING MULTI-WAVELENGTH PULSE PROFILES OF THE MILLISECOND PULSAR PSR B1821–24

    SciTech Connect

    Du, Yuanjie; Shuai, Ping; Bei, Xiaomin; Chen, Shaolong; Fu, Linzhong; Huang, Liangwei; Lin, Qingqing; Meng, Jing; Wu, Yaojun; Zhang, Hengbin; Zhang, Qian; Zhang, Xinyuan; Qiao, Guojun

    2015-03-10

    PSR B1821–24 is a solitary millisecond pulsar that radiates multi-wavelength pulsed photons. It has complex radio, X-ray, and γ-ray pulse profiles with distinct peak phase separations that challenge the traditional caustic emission models. Using the single-pole annular gap model with a suitable magnetic inclination angle (α = 40°) and viewing angle (ζ = 75°), we managed to reproduce its pulse profiles of three wavebands. It is found that the middle radio peak originated from the core gap region at high altitudes, and the other two radio peaks originated from the annular gap region at relatively low altitudes. Two peaks of both X-ray and γ-ray wavebands basically originated from the annular gap region, while the γ-ray emission generated from the core gap region contributes somewhat to the first γ-ray peak. Precisely reproducing the multi-wavelength pulse profiles of PSR B1821–24 enables us to understand emission regions of distinct wavebands and justify pulsar emission models.

  4. Modelling the multi-wavelength emission of flat-spectrum radio quasar 3C 279

    NASA Astrophysics Data System (ADS)

    Zheng, Y. G.; Yang, C. Y.

    2016-04-01

    We employ a length-dependent conical jet model for the jet structure and emission properties of flat-spectrum radio quasar 3C 279 in the steady state. In the model, ultra-relativistic leptons are injected at the base of the jet and propagate along the jet structure. Non-thermal photons are produced by both synchrotron emission and inverse Compton scattering off synchrotron photons and external soft photons at each segment of the jet. We derive the total energy spectra contribution through integrating every segment. We apply the model to the quasi-simultaneous multi-wavelength observed data of two quiescent epochs. Using the observed radio data of the source, we determine the length of the jet L ˜ 100 pc and the magnetic field B0 ˜ 0.1-1 G at the base of the jet. Assuming a steady geometry of the jet structure and suitable physical parameters, we reproduce the multi-wavelength spectra during two quiescent observed epochs. Our results show that the initial γ-ray emission site is ˜0.5 pc from the black hole.

  5. Multi-wavelength Monitoring of Lensed Quasars: Deciphering Quasar Structure at Micro-arcseconds Scales

    NASA Astrophysics Data System (ADS)

    Mosquera, Ana; Morgan, Christopher W.; Kochanek, Christopher S.; Dai, Xinyu; Chen, Bin; MacLeod, Chelsea Louise; Chartas, George

    2016-01-01

    Microlensing in multiply imaged gravitationally lensed quasars provides us with a unique tool to zoom in on the structure of AGN and explore their physics in more detail. Microlensing magnification, caused primarily by stars and white dwarfs close to the line of sight towards the lensed quasar images, is seen as uncorrelated flux variations due to the relative motions of the quasar, the lens, its stars, and the observer, and it depends on the structural and dynamical properties of the source and the lens. Since the magnification depends upon the size of the source, we can use microlensing to measure the size of quasar emission regions. In essence, the amplitude of the microlensing variability encodes the source size, with smaller sources showing larger variability amplitudes. Using state of the art microlensing techniques, our team has performed pioneering research in the field based on multi-wavelength space and ground-based observations. Among the most remarkable results, using Chandra observations we have set the first quantitative constraints on the sizes of the X-ray emission regions of quasars. In this work l briefly describe the methodology, the results from our previous multi-wavelength monitoring programs, and the next frontier of exploring the dependence of the structure of the X-ray emission regions on black hole mass and X-ray energy.

  6. Application of spectral unmixing in multi-wavelength time-resolved spectroscopy

    NASA Astrophysics Data System (ADS)

    Chorvat, D., Jr.; Mateasik, A.; Kirchnerova, J.; Chorvatova, A.

    2007-09-01

    We present a new approach for analysis of multi-wavelength time-resolved spectroscopy data, based on sequential spectral unmixing. Principal component analysis was used to identify the number and spectral profiles of the main components of intrinsic flavin signal in multi-wavelength time-resolved fluorescence recordings from isolated living cardiac myocytes. To determine these components, natural variations in the cardiomyocyte autofluorescence spectra were induced by modulators of mitochondrial metabolism and respiration. Using aforementioned approach we have identified two main components of intrinsic flavin emission in cardiac myocytes. The first component show emission maximum at 486-504 nm and mean lifetime of 1.2 nanoseconds, the second component with peak at 522 nm has two-exponential decay with fluorescence lifetimes of 0.3 and 3.1 nanoseconds. Comparison of gathered new results to our previous studies of flavins in vitro and in cardiac cells clearly points to the fact that the estimated spectral components correspond to flavin adenine dinucleotide (FAD) bound to enzyme(s) of mitochondrial metabolic chain, and to free FAD, respectively.

  7. Double spacing multi-wavelength L-band Brillouin erbium fiber laser with Raman pump

    NASA Astrophysics Data System (ADS)

    Ahmad, B. A.; Al-Alimi, A. W.; Abas, A. F.; Mokhtar, M.; Harun, S. W.; Mahdi, M. A.

    2012-11-01

    A new multi-wavelength Brillouin erbium fiber laser (BEFL), which operates in the L-band region with double frequency Brillouin spacing, is demonstrated. This design uses a Raman pump (RP) and a piece of 2 km highly nonlinear fiber as a gain medium. The double frequency spacing is achieved by employing a dual ring configuration, which is formed by utilizing a four-port circulator that removes the odd-order Stoke signals. Twenty Stokes and seventeen anti-Stokes lines, which have optical signal to noise ratio (OSNR) greater than 15 dB, are generated simultaneously with a spacing of 0.16 nm when Brillouin pump and RP powers were fixed at the optimum values of 8 dBm and 40 mW, respectively. The BEFL can be tuned in the range between 1591 nm to 1618 nm. The proposed configuration increases the number of lines generated and the OSNR, and thus allows a compact multi-wavelength laser source to be realized.

  8. [Measurement of multi-wavelength pulse oxygen saturation based on dynamic spectroscopy].

    PubMed

    Wang, Xiao-Fei; Zhao, Wen-Jun

    2014-05-01

    The present paper puts forward multi-wavelength pulse oxygen saturation measurement based on dynamic spectroscopy to do the non-invasive determination of oxygen saturation. Compared to conventional ways, the new method makes full use of more wavelengths light and improves the measurement accuracy. During the experiment, the in-vivo measurements were carried out on 60 patients and their spectroscopic data were collected by the high sensitivity type fiber optic spectrometer. Singletrial estimation method was used to extract the dynamic spectroscopy at the wavelengths of 606. 44 approximately 987. 55 nm. Oxygen saturation obtained from arterial blood gas analysis is regarded as the true value. Synergy interval partial least square (siPLS) was used to establish the calibration model of subjects' oxygen saturation values against dynamic spectroscopy data. The relative error of prediction is +/-0. 017 6, but the relative error of the subjects in the same set measured by the patient monitor which was two-wavelength measure system is +/-0. 116 4. Measurement results show that the use of the high sensitivity type fiber optic spectrometer to collect multi-wavelength spectroscopic data and dynamic spectroscopy method to process data can do better in improving the accuracy of the oxygen saturation measurement.

  9. Atmospheric aerosol characterization combining multi-wavelength Raman lidar and MAX-DOAS measurements in Gwanjgu

    NASA Astrophysics Data System (ADS)

    Chong, Jihyo; Shin, Dong Ho; Kim, Kwang Chul; Lee, Kwon-Ho; Shin, Sungkyun; Noh, Young M.; Müller, Detlef; Kim, Young J.

    2011-11-01

    Integrated approach has been adopted at the ADvanced Environmental Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosol. Various active and passive optical remote sensing techniques such as multi-wavelength (3β+2α+1δ) Raman LIDAR, sun-photometry, MAX-DOAS, and satellite retrieval have been utilized. This integrated monitoring system approach combined with in-situ surface measurement is to allow better characterization of physical and optical properties of atmospheric aerosol. Information on the vertical distribution and microphysical properties of atmospheric aerosol is important for understanding its transport characteristics as well as radiative effect. The GIST multi-wavelength (3β + 2α+1δ) Raman lidar system can measure vertical profiles of optical properties of atmospheric aerosols such as extinction coefficients at 355 and 532nm, particle backscatter coefficients at 355, 532 and 1064 nm, and depolarization ratio at 532nm. The incomplete overlap between the telescope field-of-view and beam divergence of the transmitting laser significantly affects lidar measurement, resulting in higher uncertainty near the surface where atmospheric aerosols of interest are concentrated. Differential Optical Absorption Spectroscopy (DOAS) technique is applied as a complementary tool for the detection of atmospheric aerosols near the surface. The passive Multi-Axis DOAS (MAX-DOAS) technique uses scattered sunlight as a light source from several viewing directions. Recently developed aerosol retrieval algorithm based on O4 slant column densities (SCDs) measured at UV and visible wavelengths has been utilized to derive aerosol information (e.g., aerosol optical depth (AOD) and aerosol extinction coefficients (AECs)) in the lower troposphere. The aerosol extinction coefficient at 356 nm was retrieved for the 0-1 and 1-2 km layers based on the MAX-DOAS measurements using the retrieval algorithm

  10. [Remote system of natural gas leakage based on multi-wavelength characteristics spectrum analysis].

    PubMed

    Li, Jing; Lu, Xu-Tao; Yang, Ze-Hui

    2014-05-01

    In order to be able to quickly, to a wide range of natural gas pipeline leakage monitoring, the remote detection system for concentration of methane gas was designed based on static Fourier transform interferometer. The system used infrared light, which the center wavelength was calibrated to absorption peaks of methane molecules, to irradiated tested area, and then got the interference fringes by converging collimation system and interference module. Finally, the system calculated the concentration-path-length product in tested area by multi-wavelength characteristics spectrum analysis algorithm, furthermore the inversion of the corresponding concentration of methane. By HITRAN spectrum database, Selected wavelength position of 1. 65 microm as the main characteristic absorption peaks, thereby using 1. 65 pm DFB laser as the light source. In order to improve the detection accuracy and stability without increasing the hardware configuration of the system, solved absorbance ratio by the auxiliary wave-length, and then get concentration-path-length product of measured gas by the method of the calculation proportion of multi-wavelength characteristics. The measurement error from external disturbance is caused by this innovative approach, and it is more similar to a differential measurement. It will eliminate errors in the process of solving the ratio of multi-wavelength characteristics, and can improve accuracy and stability of the system. The infrared absorption spectrum of methane is constant, the ratio of absorbance of any two wavelengths by methane is also constant. The error coefficients produced by the system is the same when it received the same external interference, so the measured noise of the system can be effectively reduced by the ratio method. Experimental tested standards methane gas tank with leaking rate constant. Using the tested data of PN1000 type portable methane detector as the standard data, and were compared to the tested data of the system

  11. Tunable multi-wavelength fiber lasers based on an Opto-VLSI processor and optical amplifiers.

    PubMed

    Xiao, Feng; Alameh, Kamal; Lee, Yong Tak

    2009-12-07

    A multi-wavelength tunable fiber laser based on the use of an Opto-VLSI processor in conjunction with different optical amplifiers is proposed and experimentally demonstrated. The Opto-VLSI processor can simultaneously select any part of the gain spectrum from each optical amplifier into its associated fiber ring, leading to a multiport tunable fiber laser source. We experimentally demonstrate a 3-port tunable fiber laser source, where each output wavelength of each port can independently be tuned within the C-band with a wavelength step of about 0.05 nm. Experimental results demonstrate a laser linewidth as narrow as 0.05 nm and an optical side-mode-suppression-ratio (SMSR) of about 35 dB. The demonstrated three fiber lasers have excellent stability at room temperature and output power uniformity less than 0.5 dB over the whole C-band.

  12. Completing multi-wavelength studies of the REFLEX-DXL sample

    NASA Astrophysics Data System (ADS)

    Zhang, Yu-Ying

    2005-10-01

    To use massive clusters as the most sensitive probes to study the evolution of cosmic structure and to test cosmological models, it is important to control the systematics of the mass--observable relations. To meet this requirements, we constructed a morphology-unbiased and volume-limited sample with a well defined flux limit, consisting of 14 distant X-ray luminous clusters in the REFLEX survey (the REFLEX-DXL sample). The sample was observed in AO1 and AO3. We published detailed studies of 13 clusters. However, the observations of RXCJ2011.3-5725 were seriously spoiled by flares. To complete the REFLEX-DXL sample to finish the multi-wavelength studies, we request a re-observation of 36 ks for RXCJ2011.3-5725.

  13. Multi-wavelength study of Galactic H II region W40

    NASA Astrophysics Data System (ADS)

    Mallick, K. K.; Kumar, M. S. N.; Ojha, D. K.; Bachiller, R.; Samal, M. R.; Pirogov, Lev

    Study of Galactic H II regions is one of the vital tools in understanding the effect of high-mass star(s). Copious amount of UV photons from high-mass stars can ionise the neighbouring ISM, injecting energy and momentum, which leads to a host of interesting features. Such regions can be used as test-beds for triggered star formation theories such as radiation driven implosion and collect-and-collapse model. Tangentially, it can also be tested if such processes can lead to the formation of second generation high-mass stars. The sheer complexity of an H II region makes multi-wavelength study an imperative. In this respect, we have carried out infrared, sub-millimeter, and radio continuum analysis of the W40 Galactic H II region to decipher the global star formation scenario. We discuss the preliminary results in this talk.

  14. Multi-wavelength resonance Raman spectroscopy of bacteria to study the effects of growth condition

    NASA Astrophysics Data System (ADS)

    Kunapareddy, Nagapratima; Grun, Jacob; Lunsford, Robert; Gillis, David; Nikitin, Sergei; Wang, Zheng

    2012-06-01

    We will examine the use of multi-wavelength UV resonance-Raman signatures to identify the effects of growth phase on different types of bacteria. Gram positive and gram-negative species, Escherichia coli, Bacillus cereus, Citrobacter koseri and Citrobacter braakii were grown to logarithmic and stationary phases in different culture media. Raman spectra of bacteria were obtained by sequential illumination of samples between 220 and 260 nm; a range which encompasses the resonance frequencies of cellular components. In addition to the information contained in the single spectrum, this two-dimensional signature contains information reflecting variations in resonance cross sections with illumination wavelength. Results of our algorithms in identifying the differences between these germs are discussed. Preliminary results indicate that growth affects the Raman signature, but not to an extent that would negate identification of the species.

  15. Multi-wavelength mid-infrared plasmonic antennas with single nanoscale focal point.

    PubMed

    Blanchard, Romain; Boriskina, Svetlana V; Genevet, Patrice; Kats, Mikhail A; Tetienne, Jean-Philippe; Yu, Nanfang; Scully, Marlan O; Dal Negro, Luca; Capasso, Federico

    2011-10-24

    We propose and demonstrate a novel photonic-plasmonic antenna capable of confining electromagnetic radiation at several mid-infrared wavelengths to a single sub-wavelength spot. The structure relies on the coupling between the localized surface plasmon resonance of a bow-tie nanoantenna with the photonic modes of surrounding multi-periodic particle arrays. Far-field measurements of the transmission through the central bow-tie demonstrate the presence of Fano-like interference effects resulting from the interaction of the bow-tie antenna with the surrounding nanoparticle arrays. The near-field of the multi-wavelength antenna is imaged using an aperture-less near-field scanning optical microscope. This antenna is relevant for the development of near-field probes for nanoimaging, spectroscopy and biosensing.

  16. Yangbajing Astronomical Observatory of NAOC in Tibet: a good multi-wavelength site

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Jie

    2015-08-01

    Yangbajing Astronomical Station of National Astronomical Observatories, Chinese Academy of Science (NAOC) is located in Yangbajing Tibet (90°31'50" E 30°06'38" N, 4300m ). It is the first professional observatory operated by NAOC for science project in Tibet. This station was established on August 17, 2011, which means that Tibet has its first astronomical observatory. There are one 3-meter in diameter submillimeter telescope CCOSMA and five 40-50 cm optical telescopes. This could lay a solid foundation for attracting more international cooperation on large telescope projects in Tibet in future. we have already tested the radio, millimeter/submillimeter and optical environment in Yangbajing. The result shows that Yangbajing station is a good desirable multi-wavelength astronomical observation site.

  17. Aerosol Properties over Southeastern China from Multi-Wavelength Raman and Depolarization Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Heese, Birgit; Althausen, Dietrich; Baars, Holger; Bohlmann, Stephanie; Deng, Ruru

    2016-06-01

    A dataset of particle optical properties of highly polluted urban aerosol over the Pearl River Delta, Guangzhou, China is presented. The data were derived from multi-wavelengths Raman and depolarization lidar PollyXT and AERONET sun photometer measurements. The measurement campaign was conducted from Nov 2011 to June 2012. High aerosol optical depth was observed in the polluted atmosphere over this megacity, with a mean value of 0.54 ± 0.33 and a peak value of even 1.9. For the particle characterization the lidar ratio and the linear particle depolarization ratio, both at 532 nm, were used. The mean values of these properties are 48.0 sr ± 10.7 sr for the lidar ratio and 4%+-4% for the particle depolarization ratio, which means most depolarization measurements stayed below 10%. So far, most of these results indicate urban pollution particles mixed with particles arisen from biomass and industrial burning.

  18. Mass specific optical absorption coefficients of mineral dust components measured by a multi wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2014-09-01

    Mass specific optical absorption coefficients of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at wavelengths of 1064, 532, 355 and 266 nm. These values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. These results are expected to have considerable importance in global radiative forcing calculations. They can also serve as reference for validating calculated wavelength dependent imaginary parts (κ) of complex refractive indices which up to now have been typically deduced from bulk phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk phase measurements.

  19. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Dallilar, Yigit; Casella, Piergiorgio; Marsh, Tom; Gandhi, Poshak; Fender, Rob; Littlefair, Stuart; Eikenberry, Steve; Garner, Alan; Stelter, Deno; Dhillon, Vik; Mooley, Kunal

    2016-07-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  20. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Eikenberry, Stephen S.; Dallilar, Yigit; Garner, Alan; Deno Stelter, R.; Gandhi, Poshak; Dhillon, Vik; Littlefair, Stuart; Marsh, Thomas; Fender, Rob P.; Mooley, Kunal

    2016-04-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  1. Direct writing of tunable multi-wavelength polymer lasers on a flexible substrate.

    PubMed

    Zhai, Tianrui; Wang, Yonglu; Chen, Li; Zhang, Xinping

    2015-08-07

    Tunable multi-wavelength polymer lasers based on two-dimensional distributed feedback structures are fabricated on a transparent flexible substrate using interference ablation. A scalene triangular lattice structure was designed to support stable tri-wavelength lasing emission and was achieved through multiple exposure processes. Three wavelengths were controlled by three periods of the compound cavity. Mode competition among different cavity modes was observed by changing the pump fluence. Both a redshift and blueshift of the laser wavelength could be achieved by bending the soft substrate. These results not only provide insight into the physical mechanisms behind co-cavity polymer lasers but also introduce new laser sources and laser designs for white light lasers.

  2. Multi-wavelength Brillouin fiber laser generation using dual-pass approach

    NASA Astrophysics Data System (ADS)

    Parvizi, R.; Ali, N. M.; Harun, S. W.; Emami, S. D.; Ahmad, H.

    2012-03-01

    A simple and compact multi-wavelength tunable Brillouin fiber laser (BFL) in conjunction with dual-pass approach is proposed and experimentally compared with the output of a conventional single ring cavity architecture. This BFL source is demonstrated using 10 km long non-zero dispersion shifted fiber (NZ-DSF) as a Brillouin gain medium. By single ring cavity configuration, odd-order Brillouin Stokes lines appear in the backward direction with the line spacing 0.16 nm (˜20 GHz) between each two consecutive waves. However, this single ring cavity in conjunction with dual-pass configuration is able to generate Brillouin Stokes lines with 0.08 nm spacing by providing bi-directional oscillations of Brillouin waves in both forward and backward directions. With a Brillouin pump power of 15.3 dBm, approximately up to 17 Brillouin Stokes lines are generated which is tunable over 40 nm tuning range.

  3. Flexibly switchable multi-wavelength fiber optical parametric oscillator based on a Lyot-Sagnac filter

    NASA Astrophysics Data System (ADS)

    Hu, K.; Wei, Y.; Sun, B.; Wang, T.; Chen, D.

    2012-12-01

    We experimentally demonstrate a flexibly switchable multi-wavelength fiber optical parametric oscillator (MW-FOPO) by employing a highly nonlinear dispersion-shifted fiber (HNL-DSF) as the gain medium and a Lyot-Sagnac fiber ring as the comb filter. The wavelength spacing and the number of channels in the switchable MW-FOPO are adjustable by controlling the effective length of polarization maintaining fiber (PMF) segments in the intracavity Lyot-Sagnac filter. We achieve 36 lasing channels with 0.5 nm-spacing and 22 lasing channels with 0.8 nm-spacing in a wavelength range from 1541 to 1559 nm at room temperature. A comparison of the output spectra between the dual-pump MW-FOPO and single-pump MW-FOPO is presented as well.

  4. A 12 GHz wavelength spacing multi-wavelength laser source for wireless communication systems

    NASA Astrophysics Data System (ADS)

    Peng, P. C.; Shiu, R. K.; Bitew, M. A.; Chang, T. L.; Lai, C. H.; Junior, J. I.

    2017-08-01

    This paper presents a multi-wavelength laser source with 12 GHz wavelength spacing based on a single distributed feedback laser. A light wave generated from the distributed feedback laser is fed into a frequency shifter loop consisting of 50:50 coupler, dual-parallel Mach-Zehnder modulator, optical amplifier, optical filter, and polarization controller. The frequency of the input wavelength is shifted and then re-injected into the frequency shifter loop. By re-injecting the shifted wavelengths multiple times, we have generated 84 optical carriers with 12 GHz wavelength spacing and stable output power. For each channel, two wavelengths are modulated by a wireless data using the phase modulator and transmitted through a 25 km single mode fiber. In contrast to previously developed schemes, the proposed laser source does not incur DC bias drift problem. Moreover, it is a good candidate for radio-over-fiber systems to support multiple users using a single distributed feedback laser.

  5. Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide

    NASA Astrophysics Data System (ADS)

    Russo, V.; Ghidelli, M.; Gondoni, P.; Casari, C. S.; Li Bassi, A.

    2014-02-01

    In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325 nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

  6. Electro-optically tunable, multi-wavelength optical parametric generators in aperiodically poled lithium niobates.

    PubMed

    Chen, Y H; Chung, H P; Chang, W K; Lyu, H T; Chang, J W; Tseng, C H

    2012-12-17

    We report on the design and demonstration of electro-optically tunable, multi-wavelength optical parametric generators (OPGs) based on aperiodically poled lithium niobate (APPLN) crystals. Two methods have been proposed to significantly enhance the electro-optic (EO) tunability of an APPLN OPG constructed by the aperiodic optical superlattice (AOS) technique. This is done by engineering the APPLN domain structure either in the crystal fabrication or in the crystal design process to increase the length or block-number difference of the two opposite-polarity domains used in the structure. Several orders of magnitude enhancement on the EO tuning rate of the APPLN OPGs constructed by the proposed techniques for simultaneous multiple signal wavelength generation over a conventional one has been demonstrated in a near infrared band (1500-1600 nm).

  7. Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state

    NASA Astrophysics Data System (ADS)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barnacka, A.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; O'C. Drury, L.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzynski, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Klochkov, D.; Kluzniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; Maxted, N.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Nguyen, N.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sikora, M.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, L.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Sushch, I.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Viana, A.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.; Fermi LAT Collboration; Abdo, A. A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bonamente, E.; Borgland, A. W.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Cannon, A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Çelik, Ö.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cutini, S.; Dermer, C. D.; de Palma, F.; Do Couto E Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Escande, L.; Favuzzi, C.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lee, S.-H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Mazziotta, M. N.; McConville, W.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nishino, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Sadrozinski, H. F.-W.; Sanchez, D.; Sander, A.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Strickman, M. S.; Suson, D. J.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Troja, E.; Uehara, T.; Usher, T. L.; Vandenbroucke, J.; Vianello, G.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Ylinen, T.; Ziegler, M.

    2011-09-01

    The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV γ-ray (H.E.S.S.), GeV γ-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E > 100 GeV) spectrum measured with H.E.S.S.

  8. High-Resolution Multi-Wavelength Observations of AGN Obscurers and Absorbers

    NASA Astrophysics Data System (ADS)

    Behar, Ehud

    2017-08-01

    The talk will include highlights from several of our recent multi-wavelength campaigns on AGN Outflows.New results from XMM-Newton, HST, NuStar and Swift will be shown.The fast, obscurers - transient on different time scales - which are observed in NGC 5548, and just this year in NGC 3783, will be compared with the steady, ionized absorbers that are prevalent in Seyfert galaxies.Their different roles in the AGN system and contributions to galactic feedback will be discussed and quantified.The challenge of measuring the variability of these absorbers will be exemplified at high resolution, and the best constraints will be presented.Finally, simultaneous X-ray and radio monitoring of NGC 7469 will be shown and the connection between the X-ray and radio source in this AGN will be demonstrated.

  9. Multi-channel multi-carrier generation using multi-wavelength frequency shifting recirculating loop.

    PubMed

    Li, Xinying; Yu, Jianjun; Dong, Ze; Zhang, Junwen; Shao, Yufeng; Chi, Nan

    2012-09-24

    We propose and experimentally demonstrate a novel scheme to generate optical frequency-locked multi-channel multi-carriers (MCMC), using a recirculating frequency shifter (RFS) loop based on multi-wavelength frequency shifting single side band (MWFS-SSB) modulation. In this scheme, optical subcarriers with multiple wavelengths can be generated each round. Furthermore, the generated MCMC are frequency- and phase-locked within each channel, and therefore can be effectively used for WDM superchannel. Dual-wavelength frequency shifting SSB modulation is carried out with dual-wavelength optical seed source in our experimental demonstration. Using this scheme, we successfully generate dual-channel multi-carriers, and one channel has 28 subcarriers while the other has 29 ones with 25-GHz subcarrier spacing. We also experimentally demonstrate that this kind of source can be used to carry 50-Gb/s optical polarization-division-multiplexing quadrature phase shift keying (PDM-QPSK) signal.

  10. Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide

    SciTech Connect

    Russo, V.; Ghidelli, M.; Gondoni, P.

    2014-02-21

    In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325 nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

  11. Measurements of aerosol and cloud layers using a multi-wavelength Elastic-Raman lidar

    NASA Astrophysics Data System (ADS)

    Arapi, A.

    2016-12-01

    Aerosols and clouds play an important role in air-quality, weather and climate relevant studies. The discrimination of aerosol and cloud and their subtype classification are critical in the remote sensing measurements from ground and space. In this presentation, we first present the visual measurements of aloft aerosol and cloud layers from a multi-wavelength Elastic-Raman lidar this summer in New York City. Then, we implement an algorithm and Matlab codes for discriminating aerosol and cloud based on spectral dependence or attenuated color-ratio of aerosols and clouds. The color-ratios at the three-wavelength pairs and the different thresholds are examined for improving the detection sensitivity or capability. Furthermore, a wavelet-analysis technique with different scales parameter is refined to estimate the heights of aerosol and clouds. Finally, a few cases studies are shown for the algorithm evaluation.

  12. Absolute positioning by multi-wavelength interferometry referenced to the frequency comb of a femtosecond laser.

    PubMed

    Wang, Guochao; Jang, Yoon-Soo; Hyun, Sangwon; Chun, Byung Jae; Kang, Hyun Jay; Yan, Shuhua; Kim, Seung-Woo; Kim, Young-Jin

    2015-04-06

    A multi-wavelength interferometer utilizing the frequency comb of a femtosecond laser as the wavelength ruler is tested for its capability of ultra-precision positioning for machine axis control. The interferometer uses four different wavelengths phase-locked to the frequency comb and then determines the absolute position through a multi-channel scheme of detecting interference phases in parallel so as to enable fast, precise and stable measurements continuously over a few meters of axis-travel. Test results show that the proposed interferometer proves itself as a potential candidate of absolute-type position transducer needed for next-generation ultra-precision machine axis control, demonstrating linear errors of less than 61.9 nm in peak-to-valley over a 1-meter travel with an update rate of 100 Hz when compared to an incremental-type He-Ne laser interferometer.

  13. Demonstration of multi-wavelength tunable fiber lasers based on a digital micromirror device processor.

    PubMed

    Ai, Qi; Chen, Xiao; Tian, Miao; Yan, Bin-bin; Zhang, Ying; Song, Fei-jun; Chen, Gen-xiang; Sang, Xin-zhu; Wang, Yi-quan; Xiao, Feng; Alameh, Kamal

    2015-02-01

    Based on a digital micromirror device (DMD) processor as the multi-wavelength narrow-band tunable filter, we demonstrate a multi-port tunable fiber laser through experiments. The key property of this laser is that any lasing wavelength channel from any arbitrary output port can be switched independently over the whole C-band, which is only driven by single DMD chip flexibly. All outputs display an excellent tuning capacity and high consistency in the whole C-band with a 0.02 nm linewidth, 0.055 nm wavelength tuning step, and side-mode suppression ratio greater than 60 dB. Due to the automatic power control and polarization design, the power uniformity of output lasers is less than 0.008 dB and the wavelength fluctuation is below 0.02 nm within 2 h at room temperature.

  14. Application of multi-wavelength fluorometry for on-line monitoring of an anaerobic digestion process.

    PubMed

    Morel, E; Santamaria, K; Perrier, M; Guiot, S R; Tartakovsky, B

    2004-01-01

    This work examined the use of multi-wavelength fluorometry for on-line monitoring of an anaerobic digestion process. Experiments were carried out in a laboratory-scale anaerobic digestor fed with either synthetic or agricultural (cheese factory) wastewater. An in-line fiber optic probe installed in the external recirculation loop of the reactor was used to acquire fluorescence spectra with an interval of 5-10 min. The spectra were compared with analytical measurements taken at the same time to develop regression models, which were then used to predict concentrations of chemical oxygen demand, volatile fatty acids, and other key process parameters. A comparison of partial least squares (PLS), nonlinear principal components regression, and step-wise regression models on an independent set of data showed that the PLS model gave the best prediction accuracy.

  15. The astrocosmic databases for multi-wavelength and cosmological properties of extragalactic sources

    NASA Astrophysics Data System (ADS)

    Vavilova, I. B.; Ivashchenko, G. Yu.; Babyk, Yu. V.; Sergijenko, O.; Dobrycheva, D. V.; Torbaniuk, O. O.; Vasylenko, A. A.; Pulatova, N. G.

    2015-12-01

    The article briefly describes the new specially-oriented Astro Space databases obtained with ground-based telescopes and space observatories. As a result, multi-wavelength spectral and physical properties of galaxies and galaxy clusters were analyzed in more details, particularly 1) to study the spectral properties of quasars and the distribution of matter in intergalactic scales using Lyman-alpha forest; 2) to study galaxies (including with active nuclei), especially for the formation of large-scale structures in the Universe and influence of the environment on the internal parameters of galaxies; 3) to estimate a visible and dark matter content in galaxy clusters and to test cosmological parameters and the evolution of matter in a wide range of age of the Universe.

  16. Noctilucent cloud particle size determination based on multi-wavelength all-sky analysis

    NASA Astrophysics Data System (ADS)

    Ugolnikov, Oleg S.; Galkin, Alexey A.; Pilgaev, Sergey V.; Roldugin, Alexey V.

    2017-10-01

    The article deals with the analysis of color distribution in noctilucent clouds (NLC) in the sky based on multi-wavelength (RGB) CCD-photometry provided with the all-sky camera in Lovozero in the north of Russia (68.0°N, 35.1°E) during the bright expanded NLC performance in the night of August 12, 2016. Small changes in the NLC color across the sky are interpreted as the atmospheric absorption and extinction effects combined with the difference in the Mie scattering functions of NLC particles for the three color channels of the camera. The method described in this paper is used to find the effective monodisperse radius of particles about 55 nm. The result of these simple and cost-effective measurements is in good agreement with previous estimations of comparable accuracy. Non-spherical particles, Gaussian and lognormal distribution of the particle size are also considered.

  17. A linearly frequency-swept high-speed-rate multi-wavelength laser for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wang, Qiyu; Wang, Zhaoying; Yuan, Quan; Ma, Rui; Du, Tao; Yang, Tianxin

    2017-02-01

    We proposed and demonstrated a linearly frequency-swept multi-wavelength laser source for optical coherence tomography (OCT) eliminating the need of wavenumber space resampling in the postprocessing progress. The source consists of a multi-wavelength fiber laser source (MFS) and an optical sweeping loop. In this novel laser source, an equally spaced multi-wavelength laser is swept simultaneously by a certain step each time in the frequency domain in the optical sweeping loop. The sweeping step is determined by radio frequency (RF) signal which can be precisely controlled. Thus the sweeping behavior strictly maintains a linear relationship between time and frequency. We experimentally achieved linear time-frequency sweeping at a sweeping rate of 400 kHz with our laser source.

  18. Tunable multi-wavelength SOA based linear cavity dual-output port fiber laser using Lyot-Sagnac loop mirror.

    PubMed

    Ummy, M A; Madamopoulos, N; Joyo, A; Kouar, M; Dorsinville, R

    2011-02-14

    We propose and demonstrate a simple dual port tunable from the C- to the L-band multi-wavelength fiber laser based on a SOA designed for C-band operation and fiber loop mirrors. The laser incorporates a polarization maintaining fiber in one of the fiber loop mirrors and delivers multi-wavelength operation at 9 laser lines with a wavelength separation of ~2.8 nm at room temperature. We show that the number of lasing wavelengths increases with the increase of the bias current of the SOA. Wavelength tunability from the C to L-band is achieved by exploiting the gain compression of a SOA. Stable multi-wavelength operation is achieved at room temperature without temperature compensation techniques, with measured power and the wavelength stability within < ±0.5 dB and 
±0.1 nm, respectively.

  19. A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Bi, Wei-hong; Fu, Xing-hu; Jiang, Peng; Wu, Yang

    2015-11-01

    In this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss are equal, so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature. The experimental results show that the laser can output stable multi-wavelength lasers simultaneously. The laser coupling loss is small, the structure is simple, and it is convenient for integration, so it can be widely used in dense wavelength division multiplexing (DWDM) system and optical fiber sensors.

  20. Multi-wavelength fibril dynamics and oscillations above sunspot - I. morphological signature

    NASA Astrophysics Data System (ADS)

    Sungging Mumpuni, Emanuel; Herdiwijaya, Dhani; Djamal, Mitra; Djamaluddin, Thomas

    2015-11-01

    In this work we selected one particular fibril from a high resolution observation of the solar chromosphere with the Dutch Open Telescope, and tried to obtain a broad picture of the intricate mechanism that might be operating in the multiple layers of the solar atmosphere visible in high cadence multi-wavelength observations. We analyzed the changing fibril pattern using multi-wavelength tomography, which consists of both the Hα line center and the blue wing, Doppler signal, Ca II H, and the G-band. We have found that the intermittent ejected material through the fibril from Doppler images has clearly shown an oscillation mode, as seen in the Hα blue wing. The oscillations in the umbrae and penumbrae magnetic field lines that are above the sunspot cause a broadening and the area forms a ring shape from 3 to 15 minute oscillations as a function of height. These made a distinct boundary between the umbrae and penumbrae which suggests a comb structure, and indicates that the oscillations could propagate along the inclined magnetic flux tubes from below. The 3 minute oscillations strongly appeared in the broadly inclined penumbrae magnetic field lines and showed a clear light bridge. The well known 5 minute oscillations were dominant in the umbrae-penumbrae region boundary. The long 7 minute oscillations were transparent in the Hα blue wing, as well as the 10 and 15 minute oscillations. They were concentrated in the inner-penumbrae, as seen in the Hα line center. From these findings we propose that the fibril acts as a fabric for interaction between the layers, as well as related activities around the active region under investigation.

  1. Probabilistic classification method on multi wavelength chromatographic data for photosynthetic pigments identification

    NASA Astrophysics Data System (ADS)

    Prilianti, K. R.; Setiawan, Y.; Indriatmoko, Adhiwibawa, M. A. S.; Limantara, L.; Brotosudarmo, T. H. P.

    2014-02-01

    Environmental and health problem caused by artificial colorant encourages the increasing usage of natural colorant nowadays. Natural colorant refers to the colorant that is derivate from living organism or minerals. Extensive research topic has been done to exploit these colorant, but recent data shows that only 0.5% of the wide range of plant pigments in the earth has been exhaustively used. Hence development of the pigment characterization technique is an important consideration. High-performance liquid chromatography (HPLC) is a widely used technique to separate pigments in a mixture and identify it. In former HPLC fingerprinting, pigment characterization was based on a single chromatogram from a fixed wavelength (one dimensional) and discard the information contained at other wavelength. Therefore, two dimensional fingerprints have been proposed to use more chromatographic information. Unfortunately this method leads to the data processing problem due to the size of its data matrix. The other common problem in the chromatogram analysis is the subjectivity of the researcher in recognizing the chromatogram pattern. In this research an automated analysis method of the multi wavelength chromatographic data was proposed. Principal component analysis (PCA) was used to compress the data matrix and Maximum Likelihood (ML) classification was applied to identify the chromatogram pattern of the existing pigments in a mixture. Three photosynthetic pigments were selected to show the proposed method. Those pigments are β-carotene, fucoxanthin and zeaxanthin. The result suggests that the method could well inform the existence of the pigments in a particular mixture. A simple computer application was also developed to facilitate real time analysis. Input of the application is multi wavelength chromatographic data matrix and the output is information about the existence of the three pigments.

  2. Multi-wavelength study of a high velocity event near a sunspot

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Hsien; Banerjee, D.; O'Shea, E.; Doyle, J. G.

    2006-05-01

    Context: .Jets with velocities higher than 200 km s-1 are often observed in the X-ray spectral range in the solar atmosphere, however, very few such objects are observed in the EUV range. Aims: .We report on an eruptive event observed in the south-west side of a sunspot, within active region, AR0554, in a range of spectral lines formed in the transition region and corona. Methods: .The main data were time-series observations obtained with the Coronal Diagnostic Spectrometer (CDS), in addition to images from the Michelson Doppler Imager (MDI) and Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory. Additional high resolution images from the Transition Region and Coronal Explorer (TRACE) were also used. Results: .The event brightened a loop connecting the sunspot and a bright-point structure, triggering both a high-speed flow in the loop and a transient, low-speed ambient flow into the sunspot. The energy released is quickly conducted to the chromosphere, as deduced from the TRACE 1600 Å images and the light curve of He i 522 Å as seen by CDS. The results from our multi-wavelength study further indicates that the effect of the eruptive event may have reached temperatures higher than 2 × 106 K. Relative Doppler velocities of over 300 km s-1 were detected in the transition region line, O v 629 Å. Conclusions: .The multi-wavelength analysis indicates that the event is likely due to fast magnetic reconnection in the transition region. The velocities detected are consistent with the results obtained by the evaporation jet model.

  3. Multi-wavelength Raman Spectroscopic Study of Silica-supported Vanadium Oxide Catalysts

    SciTech Connect

    Wu, Zili; Dai, Sheng; Overbury, Steven {Steve} H

    2010-01-01

    The molecular structure of silica-supported vanadium oxide (VOx) catalysts over wide range of surface VOx density (0.0002 8 V/nm2) has been investigated in detail under dehydrated condition by in situ multi-wavelength Raman spectroscopy (laser excitations at 244, 325, 442, 532, and 633 nm) and in situ UV-Vis diffuse reflectance spectroscopy. Resonance Raman scattering is clearly observed using 244 and 325-nm excitations while normal Raman scattering occurs using excitation at the three visible wavelengths. The observation of strong fundamentals, overtones and combinational bands due to selective resonance enhancement effect helps clarify assignments of some of the VOx Raman bands (920, 1032, and 1060 cm-1) whose assignments have been controversial. The resonance Raman spectra of dehydrated VOx/SiO2 show V=O band at smaller Raman shift than that in visible Raman spectra, an indication of the presence of two different surface VOx species on dehydrated SiO2 even at sub-monolayer VOx loading. Quantitative estimation shows that the two different monomeric VOx species coexist on silica surface from very low VOx loadings and transform to crystalline V2O5 at VOx loadings above monolayer. It is postulated that one of the two monomeric VOx species has pyramidal structure and the other is in partially hydroxylated pyramidal mode. The two VOx species show similar reduction-oxidation behavior and may both participate in redox reactions catalyzed by VOx/SiO2 catalysts. This study demonstrates the advantages of multi-wavelength Raman spectroscopy over conventional single-wavelength Raman spectroscopy in structural characterization of supported metal oxide catalysts.

  4. Emissivity measurements of shocked tin using a multi-wavelength integrating sphere

    SciTech Connect

    Seifter, A; Holtkamp, D B; Iverson, A J; Stevens, G D; Turley, W D; Veeser, L R; Wilke, M D; Young, J A

    2011-11-01

    Pyrometric measurements of radiance to determine temperature have been performed on shock physics experiments for decades. However, multi-wavelength pyrometry schemes sometimes fail to provide credible temperatures in experiments, which incur unknown changes in sample emissivity, because an emissivity change also affects the spectral radiance. Hence, for shock physics experiments using pyrometry to measure temperatures, it is essential to determine the dynamic sample emissivity. The most robust way to determine the normal spectral emissivity is to measure the spectral normal-hemispherical reflectance using an integrating sphere. In this paper we describe a multi-wavelength (1.6–5.0 μm) integrating sphere system that utilizes a “reversed” scheme, which we use for shock physics experiments. The sample to be shocked is illuminated uniformly by scattering broadband light from inside a sphere onto the sample. A portion of the light reflected from the sample is detected at a point 12° from normal to the sample surface. For this experiment, we used the system to measure emissivity of shocked tin at four wavelengths for shock stress values between 17 and 33 GPa. The results indicate a large increase in effective emissivity upon shock release from tin when the shock is above 24–25 GPa, a shock stress that partially melts the sample. We also recorded an IR image of one of the shocked samples through the integrating sphere, and the emissivity inferred from the image agreed well with the integrating-sphere, pyrometer-detector data. Here, we discuss experimental data, uncertainties, and a data analysis process. We also describe unique emissivity-measurement problems arising from shock experiments and methods to overcome such problems.

  5. A Multi-wavelength 3D Model of BD+30°3639

    NASA Astrophysics Data System (ADS)

    Freeman, M. J.; Kastner, Joel H.

    2016-10-01

    We present a 3D multi-wavelength reconstruction of BD+30°3639, one of the best-studied planetary nebulae in the solar neighborhood. BD+30°3639, which hosts a [WR]-type central star, has been imaged at wavelength regimes that span the electromagnetic spectrum, from radio to X-rays. We have used the astrophysical modeling software SHAPE to construct a 3D morpho-kinematic model of BD+30°3639. This reconstruction represents the most complete 3D model of a PN to date from the standpoint of the incorporation of multi-wavelength data. Based on previously published kinematic data in optical emission lines and in lines of CO (radio) and H2 (near-IR), we were able to reconstruct BD+30's basic velocity components assuming a set of homologous velocity expansion laws combined with collimated flows along the major axis of the nebula. We confirm that the CO “bullets” in the PN lie along an axis that is slightly misaligned with respect to the major axis of the optical nebula, and that these bullets are likely responsible for the disrupted structures of the ionized and H2-emitting shells within BD+30. Given the relative geometries and thus dynamical ages of BD+30's main structural components, it is furthermore possible that the same jets that ejected the CO bullets are responsible for the generation of the X-ray-emitting hot bubble within the PN. Comparison of alternative viewing geometries for our 3D reconstruction of BD+30°3639 with imagery of NGC 40 and NGC 6720 suggests a common evolutionary path for these nebulae.

  6. Multi-wavelength photoacoustic imaging for monitoring lesion formation during high-intensity focused ultrasound therapy

    NASA Astrophysics Data System (ADS)

    Wu, Xun; Sanders, Jean; Dundar, Murat; Oralkan, Ömer

    2017-03-01

    Photoacoustic imaging (PAI) can be used to monitor lesion formation during high-intensity focused ultrasound (HIFU) therapy because HIFU changes the optical absorption spectrum (OAS) of the tissue. However, in traditional PAI, the change could be too subtle to be observed either because the OAS does not change very significantly at the imaging wavelength or due to low signal-to-noise ratio in general. We propose a machine-learning-based method for lesion monitoring with multi-wavelength PAI (MWPAI), where PAI is repeated at a sequence of wavelengths and a stack of multi-wavelength photoacoustic (MWPA) images is acquired. Each pixel is represented by a vector and each element in the vector reflects the optical absorption at the corresponding wavelength. Based on the MWPA images, a classifier is trained to classify pixels into two categories: ablated and non-ablated. In our experiment, we create a lesion on a block of bovine tissue with a HIFU transducer, followed by MWPAI in the 690 nm to 950 nm wavelength range, with a step size of 5 nm. In the MWPA images, some of the ablated and non-ablated pixels are cropped and fed to a neural network (NN) as training examples. The NN is then applied to several groups of MWPA images and the results show that the lesions can be identified clearly. To apply MWPAI in/near real-time, sequential feature selection is performed and the number of wavelengths is decreased from 53 to 5 while retaining adequate performance. With a fast-switching tunable laser, the method can be implemented in/near real-time.

  7. The Herschel-ATLAS Data Release 1 - II. Multi-wavelength counterparts to submillimetre sources

    NASA Astrophysics Data System (ADS)

    Bourne, N.; Dunne, L.; Maddox, S. J.; Dye, S.; Furlanetto, C.; Hoyos, C.; Smith, D. J. B.; Eales, S.; Smith, M. W. L.; Valiante, E.; Alpaslan, M.; Andrae, E.; Baldry, I. K.; Cluver, M. E.; Cooray, A.; Driver, S. P.; Dunlop, J. S.; Grootes, M. W.; Ivison, R. J.; Jarrett, T. H.; Liske, J.; Madore, B. F.; Popescu, C. C.; Robotham, A. G.; Rowlands, K.; Seibert, M.; Thompson, M. A.; Tuffs, R. J.; Viaene, S.; Wright, A. H.

    2016-10-01

    This paper is the second in a pair of papers presenting data release 1 (DR1) of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), the largest single open-time key project carried out with the Herschel Space Observatory. The H-ATLAS is a wide-area imaging survey carried out in five photometric bands at 100, 160, 250, 350 and 500 μm covering a total area of 600 deg2. In this paper, we describe the identification of optical counterparts to submillimetre sources in DR1, comprising an area of 161 deg2 over three equatorial fields of roughly 12 × 4.5 deg centred at 9h, 12h and 14{^h.}5, respectively. Of all the H-ATLAS fields, the equatorial regions benefit from the greatest overlap with current multi-wavelength surveys spanning ultraviolet (UV) to mid-infrared regimes, as well as extensive spectroscopic coverage. We use a likelihood ratio technique to identify Sloan Digital Sky Survey counterparts at r < 22.4 for 250-μm-selected sources detected at ≥4σ (≈28 mJy). We find `reliable' counterparts (reliability R ≥ 0.8) for 44 835 sources (39 per cent), with an estimated completeness of 73.0 per cent and contamination rate of 4.7 per cent. Using redshifts and multi-wavelength photometry from GAMA and other public catalogues, we show that H-ATLAS-selected galaxies at z < 0.5 span a wide range of optical colours, total infrared (IR) luminosities and IR/UV ratios, with no strong disposition towards mid-IR-classified active galactic nuclei in comparison with optical selection. The data described herein, together with all maps and catalogues described in the companion paper, are available from the H-ATLAS website at www.h-atlas.org.

  8. Angularly positioned LED-based spatial-temporal color separation system.

    PubMed

    Lee, Chi-Hung

    2012-08-13

    This study proposes a two-field driving scheme for field sequential color liquid crystal displays (LCDs) without color filters. The proposed scheme is based on angularly positioned color LEDs. In each field, the angular rays of two colors are collimated by a collimation lens, redirected by a light guide, and converged by a cylindrical-lens array to map into corresponding sub-pixel positions to efficiently display color images. The three main advantages of this approach are the elimination of dye color filters, high feasibility using conventional ultra-precision machining processes, and a larger color gamut.

  9. Mode switching in a multi-wavelength distributed feedback quantum cascade laser using an external micro-cavity

    SciTech Connect

    Sidler, Meinrad; Rauter, Patrick; Blanchard, Romain; Métivier, Pauline; Capasso, Federico; Mansuripur, Tobias S.; Wang, Christine; Huang, Yong; Ryou, Jae-Hyun; Dupuis, Russell D.; Faist, Jérôme

    2014-02-03

    We demonstrate a multi-wavelength distributed feedback (DFB) quantum cascade laser (QCL) operating in a lensless external micro-cavity and achieve switchable single-mode emission at three distinct wavelengths selected by the DFB grating, each with a side-mode suppression ratio larger than 30 dB. Discrete wavelength tuning is achieved by modulating the feedback experienced by each mode of the multi-wavelength DFB QCL, resulting from a variation of the external cavity length. This method also provides a post-fabrication control of the lasing modes to correct for fabrication inhomogeneities, in particular, related to the cleaved facets position.

  10. Measurement and correction of transverse chromatic offsets for multi-wavelength retinal microscopy in the living eye.

    PubMed

    Harmening, Wolf M; Tiruveedhula, Pavan; Roorda, Austin; Sincich, Lawrence C

    2012-09-01

    A special challenge arises when pursuing multi-wavelength imaging of retinal tissue in vivo, because the eye's optics must be used as the main focusing elements, and they introduce significant chromatic dispersion. Here we present an image-based method to measure and correct for the eye's transverse chromatic aberrations rapidly, non-invasively, and with high precision. We validate the technique against hyperacute psychophysical performance and the standard chromatic human eye model. In vivo correction of chromatic dispersion will enable confocal multi-wavelength images of the living retina to be aligned, and allow targeted chromatic stimulation of the photoreceptor mosaic to be performed accurately with sub-cellular resolution.

  11. The RoF-WDM-PON for Wireless and Wire Layout with Multi-wavelength Fiber Laser and Carrier Reusing

    NASA Astrophysics Data System (ADS)

    Ji, Wei; Zheng, Zhuowen

    2013-09-01

    In this paper, we design a WDM-RoF-PON based on multi-wavelength fiber laser and CSRZ-DPSK, which can achieve wire-line and wireless access synchronously without any RF source in ONU. The multi-wavelength fiber laser is the union light source of WDM-PON. By the RSOA and downstream light source reusing, the ONU can also omit laser source and makes the WDM-PON to be colorless. The networking has the credible transmission property, including wireless access and fiber transmission. The networking also has excellent covering range.

  12. Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

    NASA Astrophysics Data System (ADS)

    O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Drake, Stephen; Richards, Anita M. S.

    2013-10-01

    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (α Boo: K2 III) and Aldebaran (α Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for α Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of α Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For α Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of α Boo. Finally, we develop a simple analytical wind model for α Boo based on our new long-wavelength flux measurements.

  13. First multi-wavelength campaign on the gamma-ray-loud active galaxy IC 310

    NASA Astrophysics Data System (ADS)

    Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Ishio, K.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Nogués, L.; Nöthe, M.; Paiano, S.; Palacio, J.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Torres-Albà, N.; Toyama, T.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Krauß, F.; Schulz, R.; Kadler, M.; Wilms, J.; Ros, E.; Bach, U.; Beuchert, T.; Langejahn, M.; Wendel, C.; Gehrels, N.; Baumgartner, W. H.; Markwardt, C. B.; Müller, C.; Grinberg, V.; Hovatta, T.; Magill, J.

    2017-07-01

    Context. The extragalactic very-high-energy gamma-ray sky is rich in blazars. These are jetted active galactic nuclei that are viewed at a small angle to the line-of-sight. Only a handful of objects viewed at a larger angle are so far known to emit above 100 GeV. Multi-wavelength studies of such objects up to the highest energies provide new insights into the particle and radiation processes of active galactic nuclei. Aims: We aim to report the results from the first multi-wavelength campaign observing the TeV detected nucleus of the active galaxy IC 310, whose jet is observed at a moderate viewing angle of 10°-20°. Methods: The multi-instrument campaign was conducted between 2012 November and 2013 January, and involved observations with MAGIC, Fermi, INTEGRAL, Swift, OVRO, MOJAVE and EVN. These observations were complemented with archival data from the AllWISE and 2MASS catalogs. A one-zone synchrotron self-Compton model was applied to describe the broadband spectral energy distribution. Results: IC 310 showed an extraordinary TeV flare at the beginning of the campaign, followed by a low, but still detectable TeV flux. Compared to previous measurements in this energy range, the spectral shape was found to be steeper during the low emission state. Simultaneous observations in the soft X-ray band showed an enhanced energy flux state and a harder-when-brighter spectral shape behavior. No strong correlated flux variability was found in other frequency regimes. The broadband spectral energy distribution obtained from these observations supports the hypothesis of a double-hump structure. Conclusions: The harder-when-brighter trend in the X-ray and VHE emission, observed for the first time during this campaign, is consistent with the behavior expected from a synchrotron self-Compton scenario. The contemporaneous broadband spectral energy distribution is well described with a one-zone synchrotron self-Compton model using parameters that are comparable to those found for

  14. Aerosol Optical Properties Characterization By Means Of The CNR-IMAA Multi-Wavelength Raman Lidar

    NASA Astrophysics Data System (ADS)

    Mona, L.; Amodeo, A.; D'Amico, G.; Pappalardo, G.

    2007-12-01

    A Raman/elastic lidar for tropospheric aerosol study is operational at CNR-IMAA (40°36'N, 15°44'E, 760 m above sea level) since May 2000 in the framework of EARLINET. Since August 2005, this system provides aerosol backscatter coefficient profiles at 1064 nm, and independent measurements of aerosol extinction and backscatter coefficient profiles at 355 and 532 nm. In this way, lidar ratio (i.e. extinction to backscatter ratio) profiles at 355 and 532 nm are also obtained. In addition, depolarization ratio measurements at 532 nm are obtained by means of detection of components of backscattered light polarized perpendicular and parallel to the direction of the linearly polarized transmitted laser beam. Depolarization ratio measurements provide information about shape and orientation of aerosolic particles, while lidar ratio measurements and wavelength dependences of both backscatter and extinction are important for aerosol characterization in terms of aerosol type and size. In addition, high quality multi-wavelength measurements (3 backscatter + 2 extinction) can allow the determination of microphysical aerosol properties (refractive index, single-scattering albedo and effective particles radii). Systematic measurements are performed three times per week according to the EARLINET schedule since May 2000, and further measurements are performed in order to investigate particular events, like dust intrusions, volcanic eruptions and forest fires. This extended dataset allows the optical characterization of aerosol located close to the surface, namely in the Planetary Boundary Layer, as well as in the free troposphere. In the free troposphere, an high occurrence of Saharan dust intrusions at CNR-IMAA (about 1 day of Saharan dust intrusion every 10 days) has been identified by means of back-trajectory analysis and in accordance with satellite images, because of the short distance from the Sahara region. In addition, CNR-IMAA is pretty close to Etna, the largest European

  15. MULTI-WAVELENGTH RADIO CONTINUUM EMISSION STUDIES OF DUST-FREE RED GIANTS

    SciTech Connect

    O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Drake, Stephen; Richards, Anita M. S.

    2013-10-01

    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (α Boo: K2 III) and Aldebaran (α Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for α Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of α Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For α Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of α Boo. Finally, we develop a simple analytical wind model for α Boo based on our new long-wavelength flux measurements.

  16. Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

    NASA Technical Reports Server (NTRS)

    O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Dranke, Stephen; Richards, Anita M. S.

    2013-01-01

    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (alpha Boo: K2 III) and Aldebaran (alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for alpha Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of alpha Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of alpha Boo. Finally, we develop a simple analytical wind model for alpha Boo based on our new long-wavelength flux measurements.

  17. A Multi-Wavelength Census of Dust and Star Formation in Galaxies at z ~ 2

    NASA Astrophysics Data System (ADS)

    Shivaei, Irene; Reddy, Naveen; MOSDEF Collaboration

    2017-01-01

    Redshift of z ~ 2 is an important era in the history of the universe, as it contains the peak of star formation rate density and quasar activity. We study the galaxy properties during this era from two different, yet complementary, aspects: by studying formation of stars and mass assembly, and exploring the properties of galactic dust. We use a wealth of multi-wavelength data, from UV to far-IR, to obtain a complete census of obscured and unobscured star formation in galaxies. Our data consists of rest-frame optical spectra from the MOSDEF survey, rest-frame UV and optical photometric data from the 3D-HST survey, and mid- and far-IR data obtained by the Spitzer and Herschel telescopes. In the MOSDEF survey, we acquired rest-frame optical spectra of ~ 1500 galaxies with the MOSFIRE spectrograph on the Keck I telescope. MOSDEF is currently the largest survey of the rest-frame optical properties of galaxies at 1.37 ≤ z ≤ 3.80. Using the multi-wavelength data sets, we show that Hα SFRs, corrected for dust attenuation using the Hβ line, accurately trace SFRs up to ~ 300 M⊙ yr-1, when compared with panchromatic (UV-to-far-IR) SED models. Using Hα SFRs for a large sample of ~ 200 galaxies at z ~ 2, we explore the SFR-M* relation and show that the slope of this relation is shallower than previously measured. We conclude that the scatter in the SFR-M* relation is dominated by uncertainties in dust correction and cannot be used to measure the star formation stochasticity. Furthermore, we investigate the robustness of Spitzer/MIPS 24 micron flux as an SFR indicator and its variation with ISM physical parameters. We find that 24 micron flux, which at z ~ 2 traces the emission from the PAH grains, significantly depends on metallicity, such that there is a PAH deficiency in metal-poor galaxies. We demonstrate that commonly-used conversions of 24 micron flux to IR luminosity underestimate the IR luminosity of low-mass galaxies by more than a factor of 2. Our results

  18. The new MQ/AAO/Strasbourg multi-wavelength and spectroscopic PNe database: MASPN

    NASA Astrophysics Data System (ADS)

    Parker, Quentin Andrew; Bojicic, Ivan; Frew, David; Acker, Agnes; Ochsenbein, Francois; MASPN Database Team

    2015-01-01

    We are in a new golden age of PN discovery. This is thanks in particular to high sensitivity, wide-field, narrow-band surveys of the Galactic plane undertaken on the UKST in Australia and the Isaac Newton telescope on La Palma. Together these telescopes and their H-alpha surveys have provided very significant Planetary Nebulae (PNe) discoveries that have more than doubled the totals accrued by all telescopes over the previous 250 years. However, these PNe are not simply more of the same found in previous catalogues. Most new PNe are more obscured, evolved and of lower surface brightness than previous compilations while others are faint but compact and more distant. This has required an extensive and time-consuming programme of spectroscopic confirmation on a variety of 2m and 4m telescopes that is now largely complete. The scope of any future large-scale PNe studies, particularly those of a statistical nature or undertaken to understand true PNe diversity and evolution should now reflect this fresh PN population landscape of the combined sample of ~3500 Galactic PNe now available. Such studies should be coloured and nuanced by these recent major discoveries and the massive, high sensitivity, high resolution, multi-wavelength imaging surveys now available across much of the electromagnetic spectrum.Following this motivation we provide, for the first time, an accessible, reliable, on-line "one-stop" SQL database for essential, up-to date information for all known Galactic PN. We have attempted to: i) Reliably remove the many PN mimics/false ID's that have biased previous compilations and subsequent studies; ii) Provide accurate, updated positions, sizes, morphologies, radial velocities, fluxes, multi-wavelength imagery and spectroscopy; iii) Link to CDS/Vizier and hence provide archival history for each object; iv) Provide an interface to sift, select, browse, collate, investigate, download and visualise the complete currently known Galactic PNe diaspora and v

  19. Tunable and switchable multi-wavelength fiber laser based on semiconductor optical amplifier and twin-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Kim, Bongkyun; Han, Jihee; Chung, Youngjoo

    2012-02-01

    Multi-wavelength fiber lasers have attracted a lot of interest, recently, because of their potential applications in wavelength-division-multiplexing (WDM) systems, optical fiber sensing, and fiber-optics instruments, due to their numerous advantages such as multiple wavelength operation, low cost, and compatibility with the fiber optic systems. Semiconductor optical amplifier (SOA)-based multi-wavelength fiber lasers exhibit stable operation because of the SOA has the property of primarily inhomogeneous broadening and thus can support simultaneous oscillation of multiple lasing wavelengths. In this letter, we propose and experimentally demonstrate a switchable multi-wavelength fiber laser employing a semiconductor optical amplifier and twin-core photonic crystal fiber (TC-PCF) based in-line interferometer comb filter. The fabricated two cores are not symmetric due to the associated fiber fabrication process such as nonuniform heat gradient in furnace and asymmetric microstructure expansion during the gas pressurization which results in different silica strut thickness and core size. The induced asymmetry between two cores considerably alters the linear power transfer, by seriously reducing it. These nominal twin cores form effective two optical paths and associated effective refractive index difference. The in-fiber comb filter is effectively constructed by splicing a section of TC-PCF between two single mode fibers (SMFs). The proposed laser can be designed to operate in stable multi-wavelength lasing states by adjusting the states of the polarization controller (PC). The lasing modes are switched by varying the state of PC and the change is reversible. In addition, we demonstrate a tunable multi-wavelength fiber laser operation by applying temperature changes to TC-PCF in the multi-channel filter.

  20. Multi-wavelength Characterization of Exoplanet Host Stars with the MUSCLES Treasury Survey

    NASA Astrophysics Data System (ADS)

    France, Kevin; Youngblood, Allison; Parke Loyd, R. O.; Schneider, Christian

    2017-01-01

    High-energy photons (X-ray to NUV) from exoplanet host stars regulate the atmospheric temperature profiles and photochemistry on orbiting planets, influencing the long-term stability of planetary atmospheres and the production of potential “biomarker” gases. However, relatively few observational and theoretical constraints exist on the high-energy irradiance from typical (i.e., weakly active) M and K dwarf exoplanet host stars. In this talk, I will describe results from a panchromatic survey (Chandra/XMM/Hubble/ground) of M and K dwarf exoplanet hosts. The MUSCLES Treasury Survey (Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems) combines UV, X-ray, and optical observations with reconstructed Lyman-alpha and EUV (100-900 Ang) radiation to create 5 Angstrom to 5 micron stellar irradiance spectra that are available as a High-Level Science Product on STScI/MAST. I will discuss how we use multi-wavelength observations to study possible abiotic production of the suggested biomarkers O2 and O3, develop scaling relations to infer the high-energy particle fluxes from these stars based on solar UV flare/particle flux measurements, calibrate visible-wavelength proxies for the high-energy irradiance, and characterize the UV variability and flare frequency of “optically inactive” M dwarfs.

  1. The Angular Momentum of Disk Galaxies: A Multi-Wavelength Study Using the Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Cortese, Luca; Catinella, B.; Springob, C. M.

    2006-12-01

    The determination of the angular momentum distribution of disk galaxies and its dependence on other galaxy properties and environment is essential in order to develop an accurate picture of galaxy formation and evolution. N-body simulations and semi-analytic models of galaxy formation within the standard cosmological framework identify the spin parameter of the dark matter halos as one of the main drivers of galaxy evolution and yield insights into its properties and distribution in present-day galaxies. Various relations have been proposed to link the halo spin parameter to observational data. In this work, we exploit such relations to obtain observational constraints for theoretical models of galaxy formation. To this extent, we used the Virtual Observatory to create a multi-wavelength database for the study of the properties of the angular momentum distribution of disk galaxies. Our sample builds upon the SFI++ database, which includes the largest collection of long-slit optical galaxy rotation curves currently available. Preliminary results of our analysis will be presented. This work is partially funded by PPARC under grant PPA/G/O/2002/00497. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation.

  2. Comparative Analysis of Oscillations of a Solar Quiet Region Using Multi-Wavelength Observations

    NASA Astrophysics Data System (ADS)

    Kontogiannis, I.; Tsiropoula, G.; Tziotziou, K.

    2010-07-01

    We analyze the temporal behavior of a solar quiet region using a set of multi-wavelength observations obtained during a coordinated campaign. The observations were acquired by the ground-based Dutch Open Telescope (DOT), the Michelson Doppler Imager (MDI) on-board SOHO and the UV filters of the Transition Region and Coronal Explorer (TRACE). A large range of height in the solar atmosphere, from the deep photosphere to the upper chromosphere is covered by these instruments. We investigate the oscillation properties of the intensities and velocities in distinct regions of the quiet Sun, i.e. internetwork, bright points (NBP) defining the network boundaries and dark mottles forming a well-defined rosette, as observed by the different instruments and in the different heights. The variations of the intensities and velocities are studied with wavelet analysis. The aim of our work is to find similarities and/or differences in the oscillatory phenomena observed in the different examined regions, as well as comprehensive information on the interaction of the oscillations and the magnetic field.

  3. Surface roughness prediction model and experimental results based on multi-wavelength fiber optic sensors.

    PubMed

    Zhu, Nan-Nan; Zhang, Jun

    2016-10-31

    The surface roughness prediction model based on a support vector machine was proposed and the multi-wavelength fiber optic sensor was established. The specimens with different surface roughness selected as the test samples were analyzed by using the prediction model when the incident wavelengths were 650 nm and 1310 nm, respectively. The working distance of 2.5 mm ~3.5 mm was chosen as the optimum measurement distance. The experimental results indicate that the error range of surface roughness is 0.74% ~7.56% at 650 nm, and the error range of surface roughness is 1.03% ~5.92% at 1310 nm. The average relative error is about 2.669% at 650 nm, while it is about 2.431% at 1310 nm. The error of roughness measurement is less than 3% by using the model, which is acceptable. The error of surface roughness based on the prediction model is smaller than that by using the characteristic curves between surface roughness and the scattering intensity ratio.

  4. Temporal characterization of a multi-wavelength Brillouin-erbium fiber laser

    NASA Astrophysics Data System (ADS)

    Lambin Iezzi, Victor; Büttner, Thomas F. S.; Tehranchi, Amirhossein; Loranger, Sébastien; Kabakova, Irina V.; Eggleton, Benjamin J.; Kashyap, Raman

    2016-05-01

    This paper provides the first detailed temporal characterization of a multi-wavelength-Brillouin-erbium fiber laser (MWBEFL) by measuring the optical intensity of the individual frequency channels with high temporal resolution. It is found that the power in each channel is highly unstable due to the excitation of several cavity modes for typical conditions of operation. Also provided is the real-time measurements of the MWBEFL output power for two configurations that were previously reported to emit phase-locked picosecond pulse trains, concluded from their autocorrelation measurements. Real-time measurements reveal a high degree of instability without the formation of a stable pulse train. Finally, we model the MWBEFL using coupled wave equations describing the evolution of the Brillouin pump, Stokes and acoustic waves in the presence of stimulated Brillouin scattering, and the optical Kerr effect. A good qualitative consistency between the simulation and experimental results is evident, in which the interference signal at the output shows strong instability as well as the chaotic behavior due to the dynamics of participating pump and Stokes waves.

  5. A Multi-Wavelength View of the Environments of Extreme Clustered Star Formation

    NASA Astrophysics Data System (ADS)

    De Buizer, James M.

    2017-01-01

    It is believed that the vast majority of, if not all, stars form within OB clusters. Most theories of star formation assume a star forms in isolation and ignore the fact that the cluster environment and, especially, the presence of extremely energetic and high mass young stellar objects nearby, may have a profound impact on the formation process of a typical cluster member. Giant HII (GHII) regions are Galactic analogs to starburst regions seen in external galaxies, hosting the most active areas of clustered star formation. As such, GHII regions represent a population of objects that can reveal a wealth of information on the environment of the earliest stages of clustered star formation and how it is affected by feedback from the most massive cluster members. This study employs new mid-infrared imaging data obtained from the airborne observatory, SOFIA, as well as archival imaging data from the near-infrared to cm radio wavelengths to create a rich multi-wavelength dataset of a dozen galactic GHII regions. These data allow quantification of the detailed physical conditions within GHII regions individually and as a population on both global and small scales.

  6. Multi-Wavelength Analysis of the Quasar CTA102 during a Dramatic Outburst in 2016 December

    NASA Astrophysics Data System (ADS)

    Jorstad, Svetlana G.; Marscher, Alan P.; Williamson, Karen E.; Larionov, Valeri M.; Smith, Paul S.; Gurwell, Mark A.; Lahteenmaki, Anne

    2017-08-01

    Abstract: The quasar CTA102 underwent a dramatic outburst from gamma-ray toradio wavelengths in late 2016. The gamma-ray emission at 0.1-200 GeV roseup to (12.1+-0.7)x10^{-6} phot/s/cm^2, with a significant flattening of the spectral index. The blazar reached an optical brightness level never observed previously, < 11 mag in R band, and an increase of the radio flux density at millimeter wavelengths with flattening of the radio spectrum was observed as well.We present analysis of multi-wavelength data during the event obtained at gamma-rays with the Fermi Large Area telescope, at X-rays provided by the NuStar X-ray telescope and Swift XRT and UVOT, in optical bands measured at different telescopes around the world along with polarimetric observations, and at mm-waves obtained at Metsahovi Radio Observatory and SubMillimeter Array, along with imaging of theparsec-scale jet of the quasar with the VLBA at 43 GHz. This research is funded in part by NASA through Fermi Guest Investigator grant NNX14AQ58G and by the National Science Foundation through grant AST-1615796.

  7. MULTI-WAVELENGTH OBSERVATIONS OF COMET C/2011 L4 (PAN-STARRS)

    SciTech Connect

    Yang, Bin; Keane, Jacqueline; Meech, Karen; Owen, Tobias; Wainscoat, Richard

    2014-04-01

    The dynamically new comet C/2011 L4 (Pan-STARRS) is one of the brightest comets observed since the great comet C/1995 O1 (Hale-Bopp). Here, we present our multi-wavelength observations of C/2011 L4 during its in-bound passage to the inner solar system. A strong absorption band of water ice at 2.0 μm was detected in the near-infrared spectra, obtained with the 8 m Gemini-North and 3 m Infrared Telescope Facility Telescopes. The companion 1.5 μm band of water ice, however, was not observed. Spectral modeling shows that the absence of the 1.5 μm feature can be explained by the presence of sub-micron-sized fine ice grains. No gas lines (i.e., CN, HCN, or CO) were observed pre-perihelion in either the optical or the submillimeter. We derived 3σ upper limits for the CN and CO production rates. The comet exhibited a very strong continuum in the optical and its slope seemed to become redder as the comet approached the Sun. Our observations suggest that C/2011 L4 is an unusually dust-rich comet with a dust-to-gas mass ratio >4.

  8. Multi-Wavelength Based Optical Density Sensor for Autonomous Monitoring of Microalgae

    PubMed Central

    Jia, Fei; Kacira, Murat; Ogden, Kimberly L.

    2015-01-01

    A multi-wavelength based optical density sensor unit was designed, developed, and evaluated to monitor microalgae growth in real time. The system consisted of five main components including: (1) laser diode modules as light sources; (2) photodiodes as detectors; (3) driver circuit; (4) flow cell; and (5) sensor housing temperature controller. The sensor unit was designed to be integrated into any microalgae culture system for both real time and non-real time optical density measurements and algae growth monitoring applications. It was shown that the sensor unit was capable of monitoring the dynamics and physiological changes of the microalgae culture in real-time. Algae biomass concentration was accurately estimated with optical density measurements at 650, 685 and 780 nm wavelengths used by the sensor unit. The sensor unit was able to monitor cell concentration as high as 1.05 g·L−1 (1.51 × 108 cells·mL−1) during the culture growth without any sample preparation for the measurements. Since high cell concentrations do not need to be diluted using the sensor unit, the system has the potential to be used in industrial microalgae cultivation systems for real time monitoring and control applications that can lead to improved resource use efficiency. PMID:26364640

  9. A High-resolution Multi-wavelength Simultaneous Imaging System with Solar Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Rao, Changhui; Zhu, Lei; Gu, Naiting; Rao, Xuejun; Zhang, Lanqiang; Bao, Hua; Kong, Lin; Guo, Youming; Zhong, Libo; Ma, Xue’an; Li, Mei; Wang, Cheng; Zhang, Xiaojun; Fan, Xinlong; Chen, Donghong; Feng, Zhongyi; Wang, Xiaoyun; Wang, Zhiyong

    2017-10-01

    A high-resolution multi-wavelength simultaneous imaging system from visible to near-infrared bands with a solar adaptive optics system, in which seven imaging channels, including the G band (430.5 nm), the Na i line (589 nm), the Hα line (656.3 nm), the TiO band (705.7 nm), the Ca ii IR line (854.2 nm), the He i line (1083 nm), and the Fe i line (1565.3 nm), are chosen, is developed to image the solar atmosphere from the photosphere layer to the chromosphere layer. To our knowledge, this is the solar high-resolution imaging system with the widest spectral coverage. This system was demonstrated at the 1 m New Vaccum Solar Telescope and the on-sky high-resolution observational results were acquired. In this paper, we will illustrate the design and performance of the imaging system. The calibration and the data reduction of the system are also presented.

  10. Multi-wavelength injection seeded mid-infrared optical parametric oscillator for DIAL

    SciTech Connect

    Webb, M.S.; Stanion, K.B.; Deane, D.J.

    1996-01-27

    We have constructed and fielded a multi-wavelength injection seeded mid-IR OPO source for DIAL. This OPO system was built for ground based remote sensing measurements of species with both broad (300 cm{sup -1}) and narrow absorption bandwidths (0.07 cm{sup -1} FWHM). The OPO utilizes a single frequency tunable diode laser for the injection seeded signal wavelength in the region from 6400 to 6700 cm{sup -1} and an angle phase-matched 5 cm LiNbO3 crystal to provide large tuning excursions on a slow time scale. The pump was a diode pumped Nd:YAG MOPA (9398 cm{sup -1}) running at 180 Hz. This pump source was repeatedly injection seeded with a different wavelength on each of film sequential shots forming a set of three pulses having wavelength separations on the order of 0.4 cm{sup -1} at a three color set repetition rate of 60 Hz. This combination of OPO signal and pump source produced a set of three time staggered idler wavelengths separated by 0.4 cm{sup -1} with the center wavelength tunable from 2700 to 3000 cm{sup -1}. This OPO system was used in field test experiments to detect the release of chemicals from a standoff distance of 3.3 Km. We present key OPO design criteria, performance data, and numerical simulations that agree with our observations of pump induced spectral impurities in the OPO output.

  11. An L-band multi-wavelength Brillouin-erbium fiber laser with switchable frequency spacing

    NASA Astrophysics Data System (ADS)

    Zhou, Xuefang; Hu, Kongwen; Wei, Yizhen; Bi, Meihua; Yang, Guowei

    2017-01-01

    In this paper, a novel L-band multi-wavelength Brillouin-erbium fiber laser consisting of two ring cavities is proposed and demonstrated. The frequency spacing can be switched, corresponding to the single and double Brillouin frequency shifts, by toggling the optical switch. Under a 980 nm pump power of 600 mw, and a Brillouin pump power of 4 mW and wavelength of 1599.4 nm, up to 16 Stokes signals with a frequency spacing of 0.089 nm and 5 Stokes signals with double spacing of 0.178 nm are generated. A wavelength tunability of 15 nm (1593 nm  -  1608 nm) is realized for both frequency spacings. The fluctuation of Stokes signals for both single and double Brillouin spacing regimes in the proposed setup is less than 1.5 dB throughout a 30 min time span.

  12. Tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal structure

    NASA Astrophysics Data System (ADS)

    Huang, Wenbin; Pu, Donglin; Qiao, Wen; Wan, Wenqiang; Liu, Yanhua; Ye, Yan; Wu, Shaolong; Chen, Linsen

    2016-08-01

    A continuously tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal cavity is demonstrated. The triangular-lattice resonator was initially fabricated through multiple interference exposure and was then replicated into a low refractive index polymer via UV-nanoimprinting. The blend of a blue-emitting conjugated polymer and a red-emitting one was used as the gain medium. Three periods in the scalene triangular-lattice structure yield stable tri-wavelength laser emission (625.5 nm, 617.4 nm and 614.3 nm) in six different directions. A uniformly aligned liquid crystal (LC) layer was incorporated into the cavity as the top cladding layer. Upon heating, the orientation of LC molecules and thus the effective refractive index of the lasing mode changes which continuously shifts the lasing wavelength. A maximum tuning range of 12.2 nm was observed for the lasing mode at 625.5 nm. This tunable tri-wavelength polymer laser is simple constructed and cost-effective. It may find application in the fields of biosensors and photonic integrated circuits.

  13. Notes on the apparent discordance of pulse oximetry and multi-wavelength haemoglobin photometry.

    PubMed

    Nijland, R; Jongsma, H W; Nijhuis, J G; Oeseburg, B; Zijlstra, W G

    1995-01-01

    Multi-wavelength photometers, blood gas analysers and pulse oximeters are widely used to measure various oxygen-related quantities. The definitions of these quantities are not always correct. This paper gives insight in the various definitions for oxygen quantities. Furthermore, the possible influences of dyshaemoglobins and fetal haemoglobin on the accuracy of pulse oximetry are discussed. As pulse oximeters are constructed for the determination of arterial oxygen saturation, they should be validated with sample oxygen saturation values and not with the oxyhaemoglobin fraction. The influence of carboxyhaemoglobin is insubstantial over an oxygen saturation range of 0% to 100%. Through the presence of methaemoglobin, pulse oximetry will give an underestimation above 70% and an overestimation below 70% oxygen saturation. The influence of fetal haemoglobin is insignificant in the neonatal use of pulse oximetry, in the range of 75% to 100% arterial oxygen saturation. However, a pulse oximeter underestimates the arterial oxygen saturation at the 25% level with 5%, if the pulse oximeter has been calibrated in human adults. Such a low level of arterial oxygen saturation can be present in the fetus during labor.

  14. Multi-wavelength optical determination of black and brown carbon in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Massabò, D.; Caponi, L.; Bernardoni, V.; Bove, M. C.; Brotto, P.; Calzolai, G.; Cassola, F.; Chiari, M.; Fedi, M. E.; Fermo, P.; Giannoni, M.; Lucarelli, F.; Nava, S.; Piazzalunga, A.; Valli, G.; Vecchi, R.; Prati, P.

    2015-05-01

    In this paper, a new way to apportion the absorption coefficient (babs) of carbonaceous atmospheric aerosols starting from a multi-wavelength optical analysis is shown. This methodology can disentangle and quantify the contribution to total absorption of equivalent black carbon (EBC) emitted by wood burning (EBCWB) and fossil fuel (EBCFF) as well as brown carbon (BrC) due to incomplete combustion. The method uses the information gathered at five different wavelengths in a renewed and upgraded version of the approach usually referred to as Aethalometer model. Moreover, we present the results of an apportionment study of carbonaceous aerosol sources performed in a rural area and in a coastal city, both located in the North-West of Italy. Results obtained by the proposed approach are validated against independent measurements of levoglucosan and radiocarbon. At the rural site the EBCWB and EBCFF relative contributions are about 40% and 60% in winter and 15% and 85% in summer, respectively. At the coastal urban site, EBCWB and EBCFF are about 15% and 85% during fall. The OC contribution to the wood burning source at the rural site results approximately 50% in winter and 10% in summer and about 15% at the coastal urban site in fall. The new methodology also provides a direct measurement of the absorption Ångström exponent of BrC (αBrC) which resulted αBrC = 3.95 ± 0.20.

  15. Closed Box Nature of Galaxy Clusters through Multi-wavelength Analysis

    NASA Astrophysics Data System (ADS)

    Farahi, Arya; Mulroy, Sarah; Evrard, August E.; Smith, Graham

    2017-08-01

    Relating observations of cluster galaxies or the gas content to the total mass of the underlying dark matter halos is a key challenge in the current cluster cosmology community. On the other hand, accurate measurement of hot and cold phase baryon covariance in clusters will offer important constraints on hydrodynamic models of cluster formation. This property covariance has been predicted by hydrodynamics simulations of Wu et al. (2015). Wu et al. (2015) predicts massive dark-matter halos are essentially ``Closed Box'' that retain all their gaseous and stellar matter, despite a diverse set of astrophysical disruptions happening inside them.We build a forward Bayesian model to constrain the mass observable scaling relation and test ``Closed Box'' scenario through the property covariance, simultanously. We, then, present results of this method applied to multi-wavelength observations of clusters from the Local Cluster Substructure Survey (LoCuSS). We find ~3σ evidence that at least one of the covariances between hot gaseous probes and stellar mass probes is negative. These results provide the first observational evidence in favor of the ``Closed Box'' nature of clusters at the high mass end.

  16. Multi-wavelength photoacoustic system based on high-power diode laser bars

    NASA Astrophysics Data System (ADS)

    Leggio, Luca; Wiśniowski, Bartosz; Gawali, Sandeep Babu; Rodríguez, Sergio; Sánchez, Miguel; Gallego, Daniel; Carpintero, Guillermo; Lamela, Horacio

    2017-03-01

    Multi-wavelength laser sources are necessary for a functional photoacoustic (PA) spectroscopy. The use of high-power diode lasers (HPDLs) has aroused great interest for their relatively low costs and small sizes if compared to solid state lasers. However, HPDLs are only available at few wavelengths and can deliver low optical energy (normally in the order of μJ), while diode laser bars (DLBs) offer more wavelengths in the market and can deliver more optical energy. We show the simulations of optical systems for beam coupling of single high-power DLBs operating at different wavelengths (i.e. 808 nm, 880 nm, 910 nm, 940 nm, and 980 nm) into 400-μm optical fibers. Then, in a separate design, the beams of the DLBs are combined in a compact system making use of dichroic mirrors and focusing lenses for beam coupling into a 400-μm optical fiber. The use of optical fibers with small core diameter (< 1 mm) is particularly suggestive for future photoacoustic endoscopy (PAE) applications that require interior examination of the body.

  17. Multi-wavelength Observations of Comet C/2011 L4 (Pan-STARRS)

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Keane, Jacqueline; Meech, Karen; Owen, Tobias; Wainscoat, Richard

    2014-04-01

    The dynamically new comet C/2011 L4 (Pan-STARRS) is one of the brightest comets observed since the great comet C/1995 O1 (Hale-Bopp). Here, we present our multi-wavelength observations of C/2011 L4 during its in-bound passage to the inner solar system. A strong absorption band of water ice at 2.0 μm was detected in the near-infrared spectra, obtained with the 8 m Gemini-North and 3 m Infrared Telescope Facility Telescopes. The companion 1.5 μm band of water ice, however, was not observed. Spectral modeling shows that the absence of the 1.5 μm feature can be explained by the presence of sub-micron-sized fine ice grains. No gas lines (i.e., CN, HCN, or CO) were observed pre-perihelion in either the optical or the submillimeter. We derived 3σ upper limits for the CN and CO production rates. The comet exhibited a very strong continuum in the optical and its slope seemed to become redder as the comet approached the Sun. Our observations suggest that C/2011 L4 is an unusually dust-rich comet with a dust-to-gas mass ratio >4.

  18. Multi-wavelength Modeling of Globular Clusters—The Millisecond Pulsar Scenario

    NASA Astrophysics Data System (ADS)

    Kopp, A.; Venter, C.; Büsching, I.; de Jager, O. C.

    2013-12-01

    The potentially large number of millisecond pulsars (MSPs) in globular cluster (GC) cores makes these parent objects ideal laboratories for studying the collective properties of an ensemble of MSPs. Such a population is expected to radiate several spectral components in the radio through γ-ray waveband. First, pulsed emission is expected via curvature and synchrotron radiation (CR and SR) and possibly even via inverse Compton (IC) scattering inside the pulsar magnetospheres. Second, unpulsed emission should transpire through the continuous injection of relativistic leptons by the MSPs into the ambient region, which in turn produce SR and IC emission when they encounter the cluster magnetic field, as well as several background photon components. In this paper we continue to develop the MSP scenario for explaining the multi-wavelength properties of GCs by considering the entire modeling chain, including the full transport equation, refined emissivities of stellar and Galactic background photons, integration of the flux along the line of sight, and comparison with observations. As an illustration, we apply the model to Terzan 5, where we can reasonably fit both the (line-of-sight-integrated) X-ray surface flux and spectral energy density data, using the first to constrain the leptonic diffusion coefficient within the GC. We lastly discuss possible future extensions to and applications of this maturing model.

  19. Smoke plume optical properties and transport observed by a multi-wavelength lidar, sunphotometer and satellite

    NASA Astrophysics Data System (ADS)

    Wu, Yonghua; Cordero, Lina; Gross, Barry; Moshary, Fred; Ahmed, Sam

    2012-12-01

    Optical characteristics and long-distance transport of smoke plumes are studied using satellite observations and ground-based remote sensing in New York City. Vertical distribution and column optical properties of aerosol plume are derived from a combination of multi-wavelength lidar and sunphotometer measurement. Aloft smoke plumes from two cases are investigated in this paper from U.S. western and south-western forest fires. The smoke source and transport pathway to the U.S. east coast are analyzed by MODIS and CALIOP imageries as well as HYSPLIT backward trajectory analysis. In both cases, the plumes have relatively high optical depth (as much as 1.2 at 500-nm) and Angstrom exponent of up to 1.8, but show different intrusion heights, source regions and transport process. Lidar profiling observations indicate these smoke plumes mixing downward into the planetary-boundary-layer which are coincident with increasing trends of surface PM2.5 (particulate matter, diameter < 2.5 μm) concentrations.

  20. CANDELS Multi-wavelength Catalogs: Source Identification and Photometry in the CANDELS COSMOS Survey Field

    NASA Astrophysics Data System (ADS)

    Nayyeri, H.; Hemmati, S.; Mobasher, B.; Ferguson, H. C.; Cooray, A.; Barro, G.; Faber, S. M.; Dickinson, M.; Koekemoer, A. M.; Peth, M.; Salvato, M.; Ashby, M. L. N.; Darvish, B.; Donley, J.; Durbin, M.; Finkelstein, S.; Fontana, A.; Grogin, N. A.; Gruetzbauch, R.; Huang, K.; Khostovan, A. A.; Kocevski, D.; Kodra, D.; Lee, B.; Newman, J.; Pacifici, C.; Pforr, J.; Stefanon, M.; Wiklind, T.; Willner, S. P.; Wuyts, S.; Castellano, M.; Conselice, C.; Dolch, T.; Dunlop, J. S.; Galametz, A.; Hathi, N. P.; Lucas, R. A.; Yan, H.

    2017-01-01

    We present a multi-wavelength photometric catalog in the COSMOS field as part of the observations by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The catalog is based on Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) and Advanced Camera for Surveys observations of the COSMOS field (centered at R.A.: {10}{{h}}{00}{{m}}{28}{{s}}, Decl.: +02^\\circ 12\\prime {21}\\prime\\prime ). The final catalog has 38671 sources with photometric data in 42 bands from UV to the infrared (∼ 0.3{--}8 μ {{m}}). This includes broadband photometry from HST, CFHT, Subaru, the Visible and Infrared Survey Telescope for Astronomy, and Spitzer Space Telescope in the visible, near-infrared, and infrared bands along with intermediate- and narrowband photometry from Subaru and medium-band data from Mayall NEWFIRM. Source detection was conducted in the WFC3 F160W band (at 1.6 μm) and photometry is generated using the Template FITting algorithm. We further present a catalog of the physical properties of sources as identified in the HST F160W band and measured from the multi-band photometry by fitting the observed spectral energy distributions of sources against templates.

  1. Cosmic rays from multi-wavelength observations of the Galactic diffuse emission

    NASA Astrophysics Data System (ADS)

    Orlando, Elena

    2016-05-01

    Cosmic rays (CRs) generate diffuse emission while interacting with the Galactic magnetic field (B-field), the interstellar gas and the radiation field. This diffuse emission extends from radio, microwaves, through X-rays, to high-energy gamma rays. Diffuse emission has considerably increased the interest of the astrophysical community due to recent detailed observations by Planck, Fermi-LAT, and by very-high energy Cherenkov telescopes. Observations of this diffuse emission and comparison with detailed predictions are used to gain information on the properties of CRs, such as their density, spectra, distribution and propagation in the Galaxy. Unfortunately disentangling and characterizing this diffuse emission strongly depends on uncertainties in the knowledge of unresolved sources, gas, radiation fields, and B-fields, other than CRs throughout the Galaxy. We discuss here the diffuse emission produced by CRs and its uncertainties, and the comparison of this predicted emission with recent multi-wavelength observations. We show insights on CR spectra and intensities. Then we address the importance for forthcoming telescopes, especially for the Square Kilometre Array telescope (SKA) and the Cherencov Telescope Array (CTA), and for missions at MeV.

  2. CANDELS Multi-wavelength Catalogs: Source Identification and Photometry in the CANDELS Extended Groth Strip

    NASA Astrophysics Data System (ADS)

    Stefanon, Mauro; Yan, Haojing; Mobasher, Bahram; Barro, Guillermo; Donley, Jennifer L.; Fontana, Adriano; Hemmati, Shoubaneh; Koekemoer, Anton M.; Lee, BoMee; Lee, Seong-Kook; Nayyeri, Hooshang; Peth, Michael; Pforr, Janine; Salvato, Mara; Wiklind, Tommy; Wuyts, Stijn; Ashby, Matthew L. N.; Castellano, Marco; Conselice, Christopher J.; Cooper, Michael C.; Cooray, Asantha R.; Dolch, Timothy; Ferguson, Henry; Galametz, Audrey; Giavalisco, Mauro; Guo, Yicheng; Willner, Steven P.; Dickinson, Mark E.; Faber, Sandra M.; Fazio, Giovanni G.; Gardner, Jonathan P.; Gawiser, Eric; Grazian, Andrea; Grogin, Norman A.; Kocevski, Dale; Koo, David C.; Lee, Kyoung-Soo; Lucas, Ray A.; McGrath, Elizabeth J.; Nandra, Kirpal; Newman, Jeffrey A.; van der Wel, Arjen

    2017-04-01

    We present a 0.4–8 μm multi-wavelength photometric catalog in the Extended Groth Strip (EGS) field. This catalog is built on the Hubble Space Telescope (HST) WFC3 and ACS data from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), and it incorporates the existing HST data from the All-wavelength Extended Groth strip International Survey (AEGIS) and the 3D-HST program. The catalog is based on detections in the F160W band reaching a depth of F160W = 26.62 AB (90% completeness, point sources). It includes the photometry for 41,457 objects over an area of ≈ 206 arcmin2 in the following bands: HST/ACS F606W and F814W; HST WFC3 F125W, F140W, and F160W; Canada–France–Hawaii Telescope (CFHT)/Megacam u*, g\\prime , r\\prime , i\\prime and z\\prime ; CFHT/WIRCAM J, H, and K S; Mayall/NEWFIRM J1, J2, J3, H1, H2, and K; Spitzer IRAC 3.6, 4.5, 5.8, and 8.0 μm. We are also releasing value-added catalogs that provide robust photometric redshifts and stellar mass measurements. The catalogs are publicly available through the CANDELS repository.

  3. Multi-Wavelength Observations of an Unusual Impulsive Flare Associated with Cme

    NASA Astrophysics Data System (ADS)

    Uddin, Wahab; Jain, Rajmal; Yoshimura, Keiji; Chandra, Ramesh; Sakao, T.; Kosugi, T.; Joshi, Anita; Despande, M. R.

    2004-12-01

    We present the results of a detailed analysis of multi-wavelength observations of a very impulsive solar flare 1B/M6.7, which occurred on 10 March, 2001 in NOAA AR 9368 (N27 W42). The observations show that the flare is very impulsive with a very hard spectrum in HXR that reveal that non-thermal emission was most dominant. On the other hand, this flare also produced a type II radio burst and coronal mass ejections (CME), which are not general characteristics for impulsive flares. In Hα we observed bright mass ejecta (BME) followed by dark mass ejecta (DME). Based on the consistency of the onset times and directions of BME and CME, we conclude that these two phenomena are closely associated. It is inferred that the energy build-up took place due to photospheric reconnection between emerging positive parasitic polarity and predominant negative polarity, which resulted as a consequence of flux cancellation. The shear increased to >80° due to further emergence of positive parasitic polarity causing strongly enhanced cancellation of flux. It appears that such enhanced magnetic flux cancellation in a strongly sheared region triggered the impulsive flare.

  4. Multi-wavelength modeling of globular clusters–the millisecond pulsar scenario

    SciTech Connect

    Kopp, A.; Venter, C.; Büsching, I.; De Jager, O. C.

    2013-12-20

    The potentially large number of millisecond pulsars (MSPs) in globular cluster (GC) cores makes these parent objects ideal laboratories for studying the collective properties of an ensemble of MSPs. Such a population is expected to radiate several spectral components in the radio through γ-ray waveband. First, pulsed emission is expected via curvature and synchrotron radiation (CR and SR) and possibly even via inverse Compton (IC) scattering inside the pulsar magnetospheres. Second, unpulsed emission should transpire through the continuous injection of relativistic leptons by the MSPs into the ambient region, which in turn produce SR and IC emission when they encounter the cluster magnetic field, as well as several background photon components. In this paper we continue to develop the MSP scenario for explaining the multi-wavelength properties of GCs by considering the entire modeling chain, including the full transport equation, refined emissivities of stellar and Galactic background photons, integration of the flux along the line of sight, and comparison with observations. As an illustration, we apply the model to Terzan 5, where we can reasonably fit both the (line-of-sight-integrated) X-ray surface flux and spectral energy density data, using the first to constrain the leptonic diffusion coefficient within the GC. We lastly discuss possible future extensions to and applications of this maturing model.

  5. Non-invasive in vivo monitoring of circulating amphotericin b using multi-wavelength photoplethysmography

    NASA Astrophysics Data System (ADS)

    Adhikari, Pratik; Eklund, Wakako; O'Neal, D. P.

    2015-03-01

    A novel multi-wavelength photoplethysmograph (PPG), previously utilized to quantify optically absorptive circulating gold nanoparticles, has demonstrated the potential to enhance therapeutic treatment predictability as pharmacokinetic metrics are provided throughout the intravenous delivery and clearance phase of amphotericin b (injected in the lipid form Abelcet®) in real-time. This report demonstrates how the PPG could be used to assess the real-time bioavailability of intravenously delivered optically-absorbing therapeutic agents. The drug currently under investigation is antifungal amphotericin b (absorption peak ~355 nm). We describe how the algorithm has been adapted to quantify the concentration of amphotericin b in the pulsatile, circulating blood based on its extinction at three wavelengths (355, 660 and 940 nm) corresponding to the peaks of amphotericin b and wavelengths for oxygen saturation measurements, respectively. We show an example of the system collecting data representing the baseline, injection, and the clearance phases. The PPG device showed a measurement range of concentrations between 0.0987 mg/mL to 0.025mg/ml in blood. An examination of the data obtained suggests that the system is well suited to sense the concentration of amphotericin b at a therapeutic dose (≍5 mg/kg/day).

  6. Multi-Wavelength Study of the 2008-2009 Outburst of V1647 Ori

    NASA Astrophysics Data System (ADS)

    García-Alvarez, D.; Wright, N. J.; Drake, J. J.; Abraham, P.; Anandarao, B. G.; Kashyap, V.; Kospal, A.; Kun, M.; Marengo, M.; Moor, A.; Peneva, S.; Semkov, E.; Venkat, V.; Sanz-Forcada, J.

    2011-12-01

    V1647 Ori is a young eruptive variable star, illuminating a reflection nebula (McNeil's Nebula). It underwent an outburst in 2003 before fading back to its pre-outburst brightness in 2006. In 2008, V1647 Ori underwent a new outburst. The observed properties of the 2003-2006 event are different in several respects from both the EXor and FUor type outbursts, and suggest that this star might represent a new class of eruptive young stars, younger and more deeply embedded than EXors, and exhibiting variations on shorter time scales than FUors. In outburst, the star lights up the otherwise invisible McNeil's nebular -- a conical cloud likely accumulated from previous outbursts. We present follow-up photometric as well as optical and near-IR spectroscopy of the nebula obtainted during the 2008-2009 outburst. We will also present results from contemporaneous X-ray observations. These multi-wavelength observations of V1647 Ori, obtained at this key early stage of the outburst, provide a snapshot of the "lighting up" of the nebula, probe its evolution through the event, and enable comparison with the 2003-2006 outburst.

  7. Compact Galaxy Groups: A Multi-wavelength Perspective Into Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Konstantopoulos, Iraklis; HCG Collaboration

    2011-01-01

    Galaxies are seldom found in isolation. As a small unit of large clusters, individual members are subject to the volition of their groupings and evolve most commonly through interactions and mergers. In the parameter-space between too many friends and none at all lie compact galaxy groups. The ones classified by Hickson (1982; Hickson compact groups, or HCGs) share the distinctive characteristics of low membership, isolation and high density. They exhibit low velocity dispersions, which which lead to prolonged interactions, when such events occur, or quasi-secular evolution, when they do not. They are also HI-deficient, to a very intriguing extent. I will be discussing multi-wavelength observations of a sample of 12 HCGs in the context of galaxy evolution in general. For example, in HCG 7 we observed the strengthening of interactions due to the complexity of the tidal field, in a system that is likely headed toward a dry merger. In the low mass grouping of HCG 31 we recorded morphological transformation reminiscent of the intermediate redshift universe, with multiple simultaneous interactions leading to the build-up of a gaseous intra-group medium. These results, along with many more, allow us to examine the overall themes that arise from the study of the aforementioned dozen: the usage of gas; the possibility of rapid morphological transformation of compact group galaxies; and the role of groups as the tail end of the galaxy clustering N-distribution.

  8. A new multi-wavelength model-based method for determination of enzyme kinetic parameters.

    PubMed

    Sorouraddin, Mohammad-Hossein; Amini, Kaveh; Naseri, Abdolhossein; Vallipour, Javad; Hanaee, Jalal; Rashidi, Mohammad-Reza

    2010-09-01

    Lineweaver-Burk plot analysis is the most widely used method to determine enzyme kinetic parameters. In the spectrophotometric determination of enzyme activity using the Lineweaver-Burk plot, it is necessary to find a wavelength at which only the substrate or the product has absorbance without any spectroscopic interference of the other reaction components. Moreover, in this method, different initial concentrations of the substrate should be used to obtain the initial velocities required for Lineweaver-Burk plot analysis. In the present work, a multi-wavelength model-based method has been developed and validated to determine Michaelis-Menten constants for some enzyme reactions. In this method, a selective wavelength region and several experiments with different initial concentrations of the substrate are not required. The absorbance data of the kinetic assays are fitted by non-linear regression coupled to the numeric integration of the related differential equation. To indicate the applicability of the proposed method, the Michaelis-Menten constants for the oxidation of phenanthridine, 6-deoxypenciclovir and xanthine by molybdenum hydroxylases were determined using only a single initial concentration of the substrate, regardless of any spectral overlap.

  9. Rapid multi-wavelength optical assessment of circulating blood volume without a priori data

    NASA Astrophysics Data System (ADS)

    Loginova, Ekaterina V.; Zhidkova, Tatyana V.; Proskurnin, Mikhail A.; Zharov, Vladimir P.

    2016-03-01

    The measurement of circulating blood volume (CBV) is crucial in various medical conditions including surgery, iatrogenic problems, rapid fluid administration, transfusion of red blood cells, or trauma with extensive blood loss including battlefield injuries and other emergencies. Currently, available commercial techniques are invasive and time-consuming for trauma situations. Recently, we have proposed high-speed multi-wavelength photoacoustic/photothermal (PA/PT) flow cytometry for in vivo CBV assessment with multiple dyes as PA contrast agents (labels). As the first step, we have characterized the capability of this technique to monitor the clearance of three dyes (indocyanine green, methylene blue, and trypan blue) in an animal model. However, there are strong demands on improvements in PA/PT flow cytometry. As additional verification of our proof-of-concept of this technique, we performed optical photometric CBV measurements in vitro. Three label dyes—methylene blue, crystal violet and, partially, brilliant green—were selected for simultaneous photometric determination of the components of their two-dye mixtures in the circulating blood in vitro without any extra data (like hemoglobin absorption) known a priori. The tests of single dyes and their mixtures in a flow system simulating a blood transfusion system showed a negligible difference between the sensitivities of the determination of these dyes under batch and flow conditions. For individual dyes, the limits of detection of 3×10-6 M‒3×10-6 M in blood were achieved, which provided their continuous determination at a level of 10-5 M for the CBV assessment without a priori data on the matrix. The CBV assessment with errors no higher than 4% were obtained, and the possibility to apply the developed procedure for optical photometric (flow cytometry) with laser sources was shown.

  10. Multi-wavelength observations of Jupiter's aurora coordinated with Hisaki and other space telescopes

    NASA Astrophysics Data System (ADS)

    Kimura, T.; Badman, S. V.; Tao, C.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Tsuchiya, F.; Bonfond, B.; Steffl, A. J.; Kraft, R.; Branduardi-Raymont, G.; Elsner, R.; Ezoe, Y.; Fujimoto, M.

    2014-12-01

    From January to April 2014, two observing campaigns by multi-wavelength remote sensing from X-ray to radio were performed to uncover energy transport process in Jupiter's plasma environment using space telescopes and ground-based facilities. These campaigns were triggered by the new Hisaki spacecraft launched in September 2013, which is an extremely ultraviolet (EUV) space telescope of JAXA designed for planetary observations. In the first campaign in January, Hubble Space Telescope (HST) made imaging of far ultraviolet (FUV) aurora with a high special resolution (0.08") through two weeks while Hisaki continuously monitored aurora and plasma torus emissions in EUV wavelength with a high temporal resolution (1 min<). We discovered new magnetospheric activities from the campaign data: e.g., internally-driven type auroral brightening associated with hot plasma injection, and plasma and electromagnetic filed modulations in the inner magnetosphere externally driven by the solar wind modulation. The second campaign in April was performed by Chandra X-ray Observatory (CXO), XMM newton, and Suzaku satellite simultaneously with Hisaki. Relativistic auroral accelerations in the polar region and hot plasma in the inner magnetosphere were captured by the X-ray space telescopes simultaneously with EUV monitoring of aurora and plasma torus. Auroral intensity in EUV indicated a clear periodicity of 45 minutes whereas the periodicity was not evident in X-ray intensity although previous observations by CXO indicated clear 40-minute periodicity in the polar cap X-ray aurora. In this presentation, we show remarkable scientific results obtained these campaigns.

  11. Multi-Wavelength Near Infrared Observations of Marum and Yasur Volcanoes, Vanuatu

    NASA Astrophysics Data System (ADS)

    Howell, Robert R.; Radebaugh, Jani; Lopes, Rosaly M.; Lorenz, Ralph D.; Turtle, Elizabeth P.

    2014-11-01

    To help understand and test models of thermal emission from planetary volcanoes, we obtained in May 2014 a variety of near-infrared observations of the very active Marum lava lake on Ambrym, Vanuatu, as well as the Strombolian activity at Yasur on Tanna. Our observations include high resolution images and movies made with standard and modified cameras and camcorders. In addition, to test the planetary emission models, which typically rely on multi-wavelength observations, we developed a small inexpensive prototype imager named "Kerby", which consists of three simultaneously active near-infrared cameras operating at 0.860, 0.775, and 0.675 microns, as well as a fourth visible wavelength RGB camera. This prototype is based on the Raspberry Pi and Pi-NoIR cameras. It can record full high definition video, and is light enough to be carried by backpack and run from batteries. To date we have concentrated on the analysis of the Marum data. During our observations of the 40 m diameter lava lake, convection was so vigorous that areas of thin crust formed only intermittently and persisted for tens of seconds to a few minutes at most. The convection pattern primarily consisted of two upwelling centers located about 8 m in from the margins on opposite sides of the lake. Horizontal velocities away from the upwelling centers were approximately 4 m/s. A hot bright margin roughly 0.4 m wide frequently formed around parts of the lake perimeter. We are in the process of establishing the absolute photometry calibration to obtain temperatures, temperature distributions, and magma cooling rates.

  12. Multi-wavelength mid-IR light source for gas sensing

    NASA Astrophysics Data System (ADS)

    Karioja, Pentti; Alajoki, Teemu; Cherchi, Matteo; Ollila, Jyrki; Harjanne, Mikko; Heinilehto, Noora; Suomalainen, Soile; Viheriälä, Jukka; Zia, Nouman; Guina, Mircea; Buczyński, Ryszard; Kasztelanic, Rafał; Kujawa, Ireneusz; Salo, Tomi; Virtanen, Sami; Kluczyński, Paweł; Sagberg, Hâkon; Ratajczyk, Marcin; Kalinowski, Przemyslaw

    2017-02-01

    Cost effective multi-wavelength light sources are key enablers for wide-scale penetration of gas sensors at Mid-IR wavelength range. Utilizing novel Mid-IR Si-based photonic integrated circuits (PICs) filter and wide-band Mid-IR Super Luminescent Light Emitting Diodes (SLEDs), we show the concept of a light source that covers 2.5…3.5 μm wavelength range with a resolution of <1nm. The spectral bands are switchable and tunable and they can be modulated. The source allows for the fabrication of an affordable multi-band gas sensor with good selectivity and sensitivity. The unit price can be lowered in high volumes by utilizing tailored molded IR lens technology and automated packaging and assembling technologies. The status of the development of the key components of the light source are reported. The PIC is based on the use of micron-scale SOI technology, SLED is based on AlGaInAsSb materials and the lenses are tailored heavy metal oxide glasses fabricated by the use of hot-embossing. The packaging concept utilizing automated assembly tools is depicted. In safety and security applications, the Mid-IR wavelength range covered by the novel light source allows for detecting several harmful gas components with a single sensor. At the moment, affordable sources are not available. The market impact is expected to be disruptive, since the devices currently in the market are either complicated, expensive and heavy instruments, or the applied measurement principles are inadequate in terms of stability and selectivity.

  13. Multi-wavelength Characterization of Brown and Black Carbon from Filter Samples

    NASA Astrophysics Data System (ADS)

    Johnson, M. M.; Yatavelli, R. L. N.; Chen, L. W. A. A.; Gyawali, M. S.; Arnott, W. P.; Wang, X.; Chakrabarty, R. K.; Moosmüller, H.; Watson, J. G.; Chow, J. C.

    2014-12-01

    Particulate matter (PM) scatters and absorbs solar radiation and thereby affects visibility, the Earth's radiation balance, and properties and lifetimes of clouds. Understanding the radiative forcing (RF) of PM is essential to reducing the uncertainty in total anthropogenic and natural RF. Many instruments that measure light absorption coefficients (βabs [λ], Mm-1) of PM have used light at near-infrared (NIR; e.g., 880 nm) or red (e.g., 633 nm) wavelengths. Measuring βabs over a wider wavelength range, especially including the ultraviolet (UV) and visible, allows for contributions from black carbon (BC), brown carbon (BrC), and mineral dust (MD) to be differentiated. This will help to determine PM RF and its emission sources. In this study, source and ambient samples collected on Teflon-membrane and quartz-fiber filters are used to characterize and develop a multi-wavelength (250 - 1000 nm) filter-based measurement method of PM light absorption. A commercially available UV-visible spectrometer coupled with an integrating sphere is used for quantifying diffuse reflectance and transmittance of filter samples, from which βabs and absorption Ǻngström exponents (AAE) of the PM deposits are determined. The filter-based light absorption measurements of laboratory generated soot and biomass burning aerosol are compared to 3-wavelength photoacoustic absorption measurements to evaluate filter media and loading effects. Calibration factors are developed to account for differences between filter types (Teflon-membrane vs. quartz-fiber), and between filters and in situ photoacoustic absorption values. Application of multi-spectral absorption measurements to existing archived filters, including specific source samples (e.g. diesel and gasoline engines, biomass burning, dust), will also be discussed.

  14. Multi-wavelength Study of Transition Region Penumbral Subarcsecond Bright Dots Using IRIS and NST

    NASA Astrophysics Data System (ADS)

    Deng, Na; Yurchyshyn, Vasyl; Tian, Hui; Kleint, Lucia; Liu, Chang; Xu, Yan; Wang, Haimin

    2016-10-01

    Using high-resolution transition region (TR) observations taken by the Interface Region Imaging Spectrograph (IRIS) mission, Tian et al. revealed numerous short-lived subarcsecond bright dots (BDs) above sunspots (mostly located in the penumbrae), which indicate yet unexplained small-scale energy releases. Moreover, whether or not these subarcsecond TR brightenings have any signature in the lower atmosphere and how they are formed are still not fully resolved. This paper presents a multi-wavelength study of the TR penumbral BDs using a coordinated observation of a near disk center sunspot with IRIS and the 1.6 m New Solar Telescope (NST) at the Big Bear Solar Observatory. NST provides high-resolution chromospheric and photospheric observations with narrowband Hα imaging spectroscopy and broadband TiO images, respectively, complementary to IRIS TR observations. A total of 2692 TR penumbral BDs are identified from a 37 minute time series of IRIS 1400 Å slit-jaw images. Their locations tend to be associated more with downflowing and darker fibrils in the chromosphere, and weakly associated with bright penumbral features in the photosphere. However, temporal evolution analyses of the BDs show that there is no consistent and convincing brightening response in the chromosphere. These results are compatible with a formation mechanism of the TR penumbral BDs by falling plasma from coronal heights along more vertical and dense magnetic loops. The BDs may also be produced by small-scale impulsive magnetic reconnection taking place sufficiently high in the atmosphere that has no energy release in the chromosphere.

  15. The Swift/UVOT Blazar Image Processing For Multi-Wavelength Campaigns And OJ287

    NASA Astrophysics Data System (ADS)

    Verrecchia, Francesco; Leto, C.; Giommi, P.; Ciprini, S.; et al.

    2016-10-01

    In the last years the Swift mission monitoring of non-GRB sources has become an essential tool in multi-frequencies time- domain studies. The ASI Science Data Center (ASDC), which hosts one of the three official Swift data archives and was deputy for the X-ray Telescope (XRT) Deep and Serendipitous surveys, has a long experience on Blazar multi-wavelength campaigns and has recently participated to various campaigns contemporary to observations of new space missions, such as Planck and NuSTAR (Balokovic et al 2016, Furniss et al. 2015, Giommi et al 2012). Since 2006 at the ASDC we have started an activity of UltraViolet Optical Telescope (UVOT) Blazar image processing. The dedicated standard processing procedure of UVOT images, using official software and calibrations, has the goal to add UVOT fluxes to source Spectral Energy Distributions (SEDs) and also support variability studies with comparison to X and gamma-ray data, even on the intra-observation time-scale. Currently data of about 430 sources have been processed, and results have been used in recent papers, such as those on Mkn 421 (Balokovic et al.2016) and OJ 287. The OJ287 UVOT image complete data processing is updated at each observation campaign and results have been published in some survey papers. The 2015 observations have been included in the internal long-term monitoring of the source and considered in the recent multi-frequency study Valtonen et al.(2016) of the new optical-UV outburst of the 12 years cycle, with comparison to the ground optical data and the contemporaneous Swift X-ray ones. We will report the results obtained with UVOT data.

  16. THE MULTI-WAVELENGTH EXTREME STARBURST SAMPLE OF LUMINOUS GALAXIES. I. SAMPLE CHARACTERISTICS

    SciTech Connect

    Laag, Edward; Croft, Steve; Canalizo, Gabriela; Lacy, Mark

    2010-12-15

    This paper introduces the Multi-wavelength Extreme Starburst Sample (MESS), a new catalog of 138 star-forming galaxies (0.1 < z < 0.3) optically selected from the Sloan Digital Sky Survey using emission line strength diagnostics to have a high absolute star formation rate (SFR; minimum 11 M{sub sun} yr{sup -1} with median SFR {approx} 61 M{sub sun} yr{sup -1} based on a Kroupa initial mass function). The MESS was designed to complement samples of nearby star-forming galaxies such as the luminous infrared galaxies (LIRGs) and ultraviolet luminous galaxies (UVLGs). Observations using the Multi-band Imaging Photometer (24, 70, and 160 {mu}m channels) on the Spitzer Space Telescope indicate that the MESS galaxies have IR luminosities similar to those of LIRGs, with an estimated median L{sub TIR} {approx} 3 x 10{sup 11} L{sub sun}. The selection criteria for the MESS objects suggest they may be less obscured than typical far-IR-selected galaxies with similar estimated SFRs. Twenty out of 70 of the MESS objects detected in the Galaxy Evolution Explorer FUV band also appear to be UVLGs. We estimate the SFRs based directly on luminosities to determine the agreement for these methods in the MESS. We compare these estimates to the emission line strength technique, since the effective measurement of dust attenuation plays a central role in these methods. We apply an image stacking technique to the Very Large Array FIRST survey radio data to retrieve 1.4 GHz luminosity information for 3/4 of the sample covered by FIRST including sources too faint, and at too high a redshift, to be detected in FIRST. We also discuss the relationship between the MESS objects and samples selected through alternative criteria. Morphologies will be the subject of a forthcoming paper.

  17. Multi-wavelength Polarimetry and Spectral Study of the M87 Jet During 2002-2008

    NASA Astrophysics Data System (ADS)

    Avachat, Sayali S.; Perlman, Eric S.; Adams, Steven C.; Cara, Mihai; Owen, Frazer; Sparks, William B.; Georganopoulos, Markos

    2016-11-01

    We present a multi-wavelength polarimetric and spectral study of the M87 jet obtained at sub-arcsecond resolution between 2002 and 2008. The observations include multi-band archival VLA polarimetry data sets along with Hubble Space Telescope (HST) imaging polarimetry. These observations have better angular resolution than previous work by factors of 2-3 and in addition, allow us to explore the time domain. These observations envelop the huge flare in HST-1 located 0.″86 from the nucleus. The increased resolution enables us to view more structure in each knot, showing several resolved sub-components. We also see apparent helical structure in the polarization vectors in several knots, with polarization vectors turning either clockwise or counterclockwise near the flux maxima in various places as well as showing filamentary undulations. Some of these characteristics are correlated with flux and polarization maxima while others are not. We also examine the total flux and fractional polarization and look for changes in both radio and optical since the observations of Perlman et al. (1999) and test them against various models based on shocks and instabilities in the jet. Our results are broadly consistent with previous spine-sheath models and recollimation shock models; however, they require additional combinations of features to explain the observed complexity, e.g., shearing of magnetic field lines near the jet surface and compression of the toroidal component near shocks. In particular, in many regions we find apparently helical features both in total flux and polarization. We discuss the physical interpretation of these features. Based on the observations made with the Karl G. Jansky Very Large Array (VLA), operated by the National Radio Astronomy Observatory (NRAO), and Hubble Sapce Telescope (HST), obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc.

  18. Multi-wavelength Study of Blazars Using Variability as a Tool

    NASA Astrophysics Data System (ADS)

    Baliyan, Kiran S.; Kaur, Navpreet; Chandra, Sunil; Sameer, Sameer; Ganesh, Shashikiran

    2016-09-01

    Active galactic nuclei (AGN) are too compact to be resolved by any existing optical telescope facility, making it difficult to understand their structure and the emission processes responsible for their huge energy output. However, variability, one of their characteristic properties, provides a tool to probe the inner regions of AGN. Blazars are the best candidates for such a study, and hence a considerable amount of effort is being made to investigate variability in these sources across the electromagnetic spectrum. Here, using the Mt. Abu infrared observatory (MIRO) blazar monitoring program, we present intra-night, inter-night, and long term aspects of the variability in S5 0716+71, 3C66A, and OJ 287. These stars show significant variability on short (a few tens of mins, to a few hours, to a few days) to long term (months to years) timescales. Based on the light travel time argument, the shortest variability timescales (micro-variability) provide upper limits to the size of the emission region. While S5 0716 shows a very high duty cycle of variability (> 80 %), 3C66A shows a much lower intra day variability (IDV) duty cycle (< 20 %). All three show rapid variations within 2.5 to 3.5 hr, which, perhaps, are generated near the vicinity of black holes. Assuming this, estimates of the masses of the black holes are made at 10^{9} , 8×10^{8}, and 2.7×10^{9} M⨀ for S5 0716+71, 3C66A, and OJ 287, respectively. Multi-wavelength light-curves for the blazar PKS 1510-089 are discussed to infer the emission processes responsible for the recent flaring episodes in this source.

  19. Multi-wavelength properties and SMBH's masses of the isolated AGNs in the Local Universe

    NASA Astrophysics Data System (ADS)

    Vavilova, I. B.; Vasylenko, A. A.; Babyk, Iu. V.; Pulatova, N. G.

    2016-08-01

    The sample of 36 nearest isolated AGNs was cross-matched by 2MIG and Veron-Cetty catalogues and limited to Ks ≤ 12.0m and Vr < 15 000 km/s in the northern sky (δ ≥ -15°). These objects were in isolation during ~ 3 Gyrs. For revealing their multi-wavelength properties we used all the available databases obtained with ground-based and space observatories (from radio to X-ray ranges). It is allowed us to separate the internal evolution mechanisms from the environment influence and consider them as two separate processes related to fueling nuclear activity and accretion on the SMBHs outside of the environment. In this report we present briefly main results, which were already published (Pulatova N., Vavilova I., Sawangwit U. et al. The 2MIG isolated AGNs - I. General and multiwavelength properties of AGNs and host galaxies in the northern sky, MNRAS, 447, Issue 3, p. 2209-2223 (2015)). We accentuate that for the first time we revealed that the host isolated galaxies with AGNs of Sy1 type (without faint companions) appear to possess the bar morphological features (e.g., the interaction with neighboring galaxies is not necessary condition for broad-line region formation). We give also current results as concerns with more detail X-ray analysis, emission features and spectral models for several AGNs for which a cumulative soft and hard energy spectrum was reconstructed. The estimates of SMBH masses show that are systematically lower than the SMBH masses of AGNs located in a dense environment.

  20. Unveiling the First Black Holes With JWST:Multi-wavelength Spectral Predictions

    NASA Astrophysics Data System (ADS)

    Natarajan, Priyamvada; Pacucci, Fabio; Ferrara, Andrea; Agarwal, Bhaskar; Ricarte, Angelo; Zackrisson, Erik; Cappelluti, Nico

    2017-04-01

    Growing supermassive black holes (˜ {10}9 {M}⊙ ) that power luminous z> 6 quasars from light seeds—the remnants of the first stars—within a Gyr of the Big Bang poses a timing challenge. The formation of massive black hole seeds via direct collapse with initial masses ˜ {10}4{--}{10}5 {M}⊙ alleviates this problem. Viable direct-collapse black hole formation sites, the satellite halos of star-forming galaxies, merge and acquire stars to produce a new, transient class of high-redshift objects, obese black hole galaxies (OBGs). The accretion luminosity outshines that of the stars in OBGs. We predict the multi-wavelength energy output of OBGs and growing Pop III remnants at z = 9 for standard and slim disk accretion, as well as high and low metallicities of the associated stellar population. We derive robust selection criteria for OBGs—a pre-selection to eliminate blue sources, followed by color-color cuts ([{F}090W-{F}220W]> 0;-0.3< [{F}200W-{F}444W]< 0.3) and the ratio of X-ray flux to rest-frame optical flux ({F}X/{F}444W\\gg 1). Our cuts sift out OBGs from other bright, high- and low-redshift contaminants in the infrared. OBGs with predicted {M}{AB}< 25 are unambiguously detectable by the Mid-Infrared Instrument (MIRI), on the upcoming James Webb Space Telescope (JWST). For parameters explored here, growing Pop III remnants with predicted {M}{AB}< 30 will likely be undetectable by JWST. We demonstrate that JWST has the power to discriminate between initial seeding mechanisms.

  1. Multi-wavelength Lens Reconstruction of a Planck and Herschel-detected Star-bursting Galaxy

    NASA Astrophysics Data System (ADS)

    Timmons, Nicholas; Cooray, Asantha; Riechers, Dominik A.; Nayyeri, Hooshang; Fu, Hai; Jullo, Eric; Gladders, Michael D.; Baes, Maarten; Bussmann, R. Shane; Calanog, Jae; Clements, David L.; da Cunha, Elisabete; Dye, Simon; Eales, Stephen A.; Furlanetto, Cristina; Gonzalez-Nuevo, Joaquin; Greenslade, Joshua; Gurwell, Mark; Messias, Hugo; Michałowski, Michał J.; Oteo, Iván; Pérez-Fournon, Ismael; Scott, Douglas; Valiante, Elisabetta

    2016-09-01

    We present a source-plane reconstruction of a Herschel and Planck-detected gravitationally lensed dusty star-forming galaxy (DSFG) at z = 1.68 using Hubble, Submillimeter Array (SMA), and Keck observations. The background submillimeter galaxy (SMG) is strongly lensed by a foreground galaxy cluster at z = 0.997 and appears as an arc with a length of ˜15″ in the optical images. The continuum dust emission, as seen by SMA, is limited to a single knot within this arc. We present a lens model with source-plane reconstructions at several wavelengths to show the difference in magnification between the stars and dust, and highlight the importance of multi-wavelength lens models for studies involving lensed DSFGs. We estimate the physical properties of the galaxy by fitting the flux densities to model spectral energy distributions leading to a magnification-corrected star-formation rate (SFR) of 390 ± 60 M {}⊙ yr-1 and a stellar mass of 1.1+/- 0.4× {10}11 {M}⊙ . These values are consistent with high-redshift massive galaxies that have formed most of their stars already. The estimated gas-to-baryon fraction, molecular gas surface density, and SFR surface density have values of 0.43 ± 0.13, 350 ± 200 {M}⊙ pc-2, and ˜ 12+/- 7 M {}⊙ yr-1 kpc-2, respectively. The ratio of SFR surface density to molecular gas surface density puts this among the most star-forming systems, similar to other measured SMGs and local ULIRGs.

  2. On designing a SWIR multi-wavelength facial-based acquisition system

    NASA Astrophysics Data System (ADS)

    Bourlai, Thirimachos; Narang, Neeru; Cukic, Bojan; Hornak, Lawrence

    2012-06-01

    In harsh environmental conditions characterized by unfavorable lighting and pronounced shadows, human recognition based on Short-Wave Infrared (0.9-1.7 microns) images may be advantageous. SWIR imagery (i) is more tolerant to low levels of obscurants like fog and smoke; (ii) the active illumination source can be eye-safe and (iii) the active illumination source is invisible to the human eye making it suitable for surveillance applications. The key drawback of current SWIR-based acquisition systems is that they lack the capability of real-time simultaneous acquisition of multiple SWIR wavelengths. The contributions of our work are four-fold. First, we constructed a SWIR multi-wavelength acquisition system (MWAS) that can capture face images at 5 different wavelengths (1150, 1250, 1350, 1450, 1550 nm) in rapid succession using a 5-filter rotating filter wheel. Each filter has a band pass of 100 nm and all 5 images are acquired within 260 milliseconds. The acquisition system utilizes a reflective optical sensor to generate a timing signal corresponding to the filter wheel position that is used to trigger each camera image acquisition when the appropriate filter is in front of the camera. The timing signal from the reflective sensor transmits to a display panel to confirm the synchronization of the camera with the wheel. Second, we performed an empirical optimization on the adjustment of the exposure time of the camera and speed of the wheel when different light sources (fluorescent, tungsten, both) were used. This improved the quality of the images acquired. Third, a SWIR spectrometer was used to measure the response from the different light sources and was used to evaluate which one provides better images as a function of wavelength. Finally, the selection of the band pass filter, to focus the camera to acquire the good quality SWIR images was done by using a number of image quality and distortion metrics (e.g. universal quality index and Structural index method).

  3. Multi-wavelength Observations of GRB 111228A and Implications for the Fireball and its Environment

    NASA Astrophysics Data System (ADS)

    Xin, Li-Ping; Wang, Yuan-Zhu; Lin, Ting-Ting; Liang, En-Wei; Lü, Hou-Jun; Zhong, Shu-Qing; Urata, Yuji; Zhao, Xiao-Hong; Wu, Chao; Wei, Jian-Yan; Huang, Kui-Yun; Qiu, Yu-Lei; Deng, Jin-Song

    2016-02-01

    Observations of very early multi-wavelength afterglows are critical to reveal the properties of the radiating fireball and its environment as well as the central engine of gamma-ray bursts (GRBs). We report our optical observations of GRB 111228A from 95 s to about 50 hr after the burst trigger and investigate its properties of the prompt gamma-rays and the ambient medium using our data and the data from the Swift and Fermi missions. Our joint optical and X-ray spectral fits to the afterglow data show that the ambient medium features a low dust-to-gas ratio. Incorporating the energy injection effect, our best fit to the afterglow light curves with the standard afterglow model via the Markov Chain Monte Carlo technique shows that {ɛ }e=(6.9+/- 0.3)× {10}-2, {ɛ }B=(7.73+/- 0.62)× {10}-6,{E}K=(6.32+/- 0.86)× {10}53 {erg}, n=0.100+/- 0.014 cm-3. The low medium density likely implies that the afterglow jet may be in a halo or in a hot ISM. A chromatic shallow decay segment observed in the optical and X-ray bands is well explained with the long-lasting energy injection from the central engine, which would be a magnetar with a period of about 1.92 ms inferred from the data. The Ep of its time-integrated prompt gamma-ray spectrum is ˜26 KeV. Using the initial Lorentz factor ({{{Γ }}}0={476}-237+225) derived from our afterglow model fit, it is found that GRB 111228A satisfies the {L}{{iso}}-{E}p,z-{{{Γ }}}0 relation and bridges the typical GRBs and low luminosity GRBs in this relation.

  4. Multi-wavelength study of the opposition effect on Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Degiorgio, K.; Ferrari, C. C.; Rodriguez, S.

    2012-12-01

    The opposition effect manifests itself as an important surge of the radiance factor when the phase angle approaches 0°. Since its discovery on Saturn's rings (1), several effects have been proposed to explain it, such as the Ring-Shadow Hiding Opposition Effect (R-SHOE), the Coherent Backscattering Opposition Effect (CBOE) or the SHOE within the regolith that may cover ring particles. The relative importance of all these effects is still badly constraint (2). It is usually assumed that the R-SHOE cannot provide such a narrow peak as observed and is therefore considered as negligible. We will show that if the full viewing and lighting geometry are considered, this effect has to be taken into account, therefore providing a very good probe to measure the thickness and the filling factor of Saturn's Rings. Furthermore, the regolith contributions to the effect, i.e. CBOE and SHOE, depend on its absorption coefficient and its mean free path (3) and therefore should then depend on the wavelength. This is not the case for the R-SHOE because it mostly depends on the filling factor, the thickness and the particle size. We will present a multi-wavelength study of Saturn's rings opposition effect supported by the data of the VIMS-CASSINI instrument (Visual and Infrared Mapping Spectrometer) and show if our understanding of those effects is incomplete as proposed by (4) or not. (1) H,Abhandl.Bayer.Akad.Wiss.K1.II18,172,188 (2) Salo and French, Icarus, 2010 (3) Hapke, Icarus, 2002, (4) Hapke et al., Journal of Geophysical Reasearch, Vol 117, 2012

  5. A Multi-wavelength Analysis of Dust and Gas in the SR 24S Transition Disk

    NASA Astrophysics Data System (ADS)

    Pinilla, P.; Pérez, L. M.; Andrews, S.; van der Marel, N.; van Dishoeck, E. F.; Ataiee, S.; Benisty, M.; Birnstiel, T.; Juhász, A.; Natta, A.; Ricci, L.; Testi, L.

    2017-04-01

    We present new Atacama Large Millimeter/sub-millimeter Array (ALMA) 1.3 mm continuum observations of the SR 24S transition disk with an angular resolution ≲ 0\\buildrel{ \\prime}\\over{.} 18 (12 au radius). We perform a multi-wavelength investigation by combining new data with previous ALMA data at 0.45 mm. The visibilities and images of the continuum emission at the two wavelengths are well characterized by a ring-like emission. Visibility modeling finds that the ring-like emission is narrower at longer wavelengths, in good agreement with models of dust-trapping in pressure bumps, although there are complex residuals that suggest potentially asymmetric structures. The 0.45 mm emission has a shallower profile inside the central cavity than the 1.3 mm emission. In addition, we find that the 13CO and C18O (J = 2-1) emission peaks at the center of the continuum cavity. We do not detect either continuum or gas emission from the northern companion to this system (SR 24N), which is itself a binary system. The upper limit for the dust disk mass of SR 24N is ≲ 0.12 {M}\\bigoplus , which gives a disk mass ratio in dust between the two components of {M}{dust,{SR}24{{S}}}/{M}{dust,{SR}24{{N}}}≳ 840. The current ALMA observations may imply that either planets have already formed in the SR 24N disk or that dust growth to millimeter sizes is inhibited there and that only warm gas, as seen by rovibrational CO emission inside the truncation radii of the binary, is present.

  6. Receiver Performance Analysis of a Multi-wavelength Sampling Integrated Path Differential Absorption CO2 Lidar

    NASA Astrophysics Data System (ADS)

    Sun, X.; Abshire, J. B.; Ramanathan, A. K.; Mao, J.; Kawa, S. R.

    2016-12-01

    A multi-wavelength sampling integrated path differential (IPDA) CO2 lidar is analyzed and modeled. The instrument transmits laser pulses at a series of wavelengths across the 1572.33 nm CO2 absorption line. The receiver measures the received laser pulse energy and time of flight at each wavelength. The measurements are then fit to a CO2 absorption line shape to determine the total column CO2 mixing ratio. The receiver model includes effects of solar background, photon detection shot noise, detector dark current, preamplifier noise and laser speckle noise. The least-square curve fit is a linear fit in the optical depth domain and the logarithm of the raw measurements. The column CO2 mixing ratio is proportional to the scaling factor resulted from the curve fit. There are several advantages to performing the curve fit in the optical depth domain: (a) the result is directly proportional to the CO2molecule number density of the column; (b) it is a standard linear least square error fit where the theory is well established; (c) there is no need to separately estimate the off-line optical transmission. The receiver model further gives insight about the effects of various instrument parameters and the difference between the atmosphere model used in the curve fit and the actual atmosphere. For example, we can use the model to estimate the biases in the retrieved CO2 mixing ratio from small errors in the meteorological data used to generate the line shape used in the curve fit. We have shown that the estimated instrument performance using this receiver model agrees with the results from our recent airborne measurements. The receiver model is also used in the simulation of the impact of the lidar measurements of the global greenhouse gas distribution and their projected impact on quantification of surface sources and sinks.

  7. Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state

    SciTech Connect

    Abramowski, A.

    2011-09-01

    The high-frequency peaked BL Lac object PKS 2005-489 was the target of amulti-wavelength campaignwith simultaneous observations in the TeV γ-ray (H.E.S.S.), GeV γ-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E> 100 GeV) spectrum measured with H.E.S.S. with a peak energy between ~ 5 and 500 GeV. Compared to observations with contemporaneous coverage in the VHE and X-ray bands in 2004, the X-ray flux was ~ 50 times higher during the 2009 campaign while the TeV γ-ray flux shows marginal variation over the years. The spectral energy distribution during this multi-wavelength campaign was fit by a one zone synchrotron self-Compton model with a well determined cutoff in X-rays. The parameters of a one zone SSC model are inconsistent with variability time scales. The variability behaviour over years with the large changes in synchrotron emission and small changes in the inverse Compton emission does not warrant an interpretation within a one-zone SSC model despite an apparently satisfying fit to the broadband data in 2009.

  8. LIVAS: a 3-D multi-wavelength aerosol/cloud climatology based on CALIPSO and EARLINET

    NASA Astrophysics Data System (ADS)

    Amiridis, V.; Marinou, E.; Tsekeri, A.; Wandinger, U.; Schwarz, A.; Giannakaki, E.; Mamouri, R.; Kokkalis, P.; Binietoglou, I.; Solomos, S.; Herekakis, T.; Kazadzis, S.; Gerasopoulos, E.; Balis, D.; Papayannis, A.; Kontoes, C.; Kourtidis, K.; Papagiannopoulos, N.; Mona, L.; Pappalardo, G.; Le Rille, O.; Ansmann, A.

    2015-01-01

    We present LIVAS, a 3-dimentional multi-wavelength global aerosol and cloud optical climatology, optimized to be used for future space-based lidar end-to-end simulations of realistic atmospheric scenarios as well as retrieval algorithm testing activities. LIVAS database provides averaged profiles of aerosol optical properties for the potential space-borne laser operating wavelengths of 355, 532, 1064, 1570 and 2050 nm and of cloud optical properties at the wavelength of 532 nm. The global climatology is based on CALIPSO observations at 532 and 1064 nm and on aerosol-type-dependent spectral conversion factors for backscatter and extinction, derived from EARLINET ground-based measurements for the UV and scattering calculations for the IR wavelengths, using a combination of input data from AERONET, suitable aerosol models and recent literature. The required spectral conversion factors are calculated for each of the CALIPSO aerosol types and are applied to CALIPSO extinction and backscatter data correspondingly to the aerosol type retrieved by the CALIPSO aerosol classification scheme. A cloud climatology based on CALIPSO measurements at 532 nm is also provided, neglecting wavelength conversion due to approximately neutral scattering behavior of clouds along the spectral range of LIVAS. Averages of particle linear depolarization ratio profiles at 532 nm are provided as well. Finally, vertical distributions for a set of selected scenes of specific atmospheric phenomena (e.g., dust outbreaks, volcanic eruptions, wild fires, polar stratospheric clouds) are analyzed and spectrally converted so as to be used as case studies for space-borne lidar performance assessments. The final global climatology includes 4-year (1 January 2008-31 December 2011) time-averaged CALIPSO data on a uniform grid of 1×1 degree with the original high vertical resolution of CALIPSO in order to ensure realistic simulations of the atmospheric variability in lidar end-to-end simulations.

  9. Mid-Infrared and multi-wavelength monitoring of the microquasar GRS 1915+105.

    NASA Astrophysics Data System (ADS)

    Fuchs, Yael; Chaty, Sylvain; Dhawan, Vivek; Diana, Hannikainen; Mirabel, Felix; Pooley, Guy; Ribo, Marc; Rodriguez, Jerome; Rupen, Michael

    2005-06-01

    We propose to continue mid-infrared photometric and spectroscopic observations of the microquasar GRS 1915+105 in the context of a campaign of multi-wavelength observations of the source. GRS 1915+105 is used as a laboratory to understand the accretion / ejection phenomena occurring in stellar-mass accreting black hole (microquasars) and by analogy in supermassive black holes (AGNs). A key question is the nature of the time-variable infrared emission in this system. Depending on the state of the source, we wish to know what is the contribution in the mid-infrared of the different possible emission mechanisms: the thermal emission from the K-M giant donor star, the synchrotron emission from the compact relativistic jets, X-ray reprocessing in the accretion disc and free-free emission from a possible disc-wind. The continuum in a wavelength range as large as possible and the possible emission lines observed thanks to the Infrared Array Camera (IRAC) and the Infrared Spectrograph (IRS) are important clues to achieve this study. These mid-infrared observations will be combined with observations with the RXTE and INTEGRAL satellites in the X-rays and gamma-rays, the ESO/NTT in near-infrared and the VLA/VLBA and Ryle Telescopes in radio. Thanks to these simultaneous multiwavelength observations we will identify the accretion state of the source and determine the contribution of each emission component of the system. As GRS 1915+105 had been rarely observed in the mid-infrared range in the past, the Spitzer Space Telescope brings the unique opportunity to do so, shedding light on the physical mechanisms occurring in this particular binary system and which could apply to the other black hole binaries.

  10. A Multi-wavelength Study of Star Formation Activity in the S235 Complex

    NASA Astrophysics Data System (ADS)

    Dewangan, L. K.; Ojha, D. K.; Luna, A.; Anandarao, B. G.; Ninan, J. P.; Mallick, K. K.; Mayya, Y. D.

    2016-03-01

    We have carried out an extensive multi-wavelength study to investigate the star formation process in the S235 complex. The S235 complex has a spherelike shell appearance at wavelengths longer than 2 μm and harbors an O9.5V type star approximately at its center. A near-infrared extinction map of the complex traces eight subregions (having AV > 8 mag), and five of them appear to be distributed in an almost regularly spaced manner along the spherelike shell surrounding the ionized emission. This picture is also supported by the integrated 12CO and 13CO intensity maps and by Bolocam 1.1 mm continuum emission. The position-velocity analysis of CO reveals an almost semi-ringlike structure, suggesting an expanding H ii region. We find that the Bolocam clump masses increase as we move away from the location of the ionizing star. This correlation is seen only for those clumps that are distributed near the edges of the shell. Photometric analysis reveals 435 young stellar objects (YSOs), 59% of which are found in clusters. Six subregions (including five located near the edges of the shell) are very well correlated with the dust clumps, CO gas, and YSOs. The average values of Mach numbers derived using NH3 data for three (East 1, East 2, and Central E) out of these six subregions are 2.9, 2.3, and 2.9, indicating these subregions are supersonic. The molecular outflows are detected in these three subregions, further confirming the ongoing star formation activity. Together, all these results are interpreted as observational evidence of positive feedback of a massive star.

  11. Multi-wavelength solar activity complexes evolution from Solar Dynamic Observatory (SDO)

    NASA Astrophysics Data System (ADS)

    Korolkova, Olga; Benevolenskaya, Elena

    The main problem of the solar physics is to understand a nature of the solar magnetic activity. New space missions and background observations provide us by data describing solar activity with a good space and time resolution. Space missions data observe the solar activity in multi-wavelength emissions come from photosphere to corona. The complex of the solar activity has roots in inte-rior and extends to the solar corona. Thus, modern data give an opportunity to study the activity on the Sun at different levels simultaneously. Solar Dynamics Observatory (SDO) [1] which launched at the beginning of 2010, looks at Sun in different wavelengths such as coronal lines 171Å & 335Å. Also SDO measures photospheric magnetic flux (line-of-sight component of the magnetic field strength) and gives images in continuum. We have studied a stable complexes of the solar activity (about 30 com-plexes) during 6 hours from 10 March 2013 to 14 October 2013 using 720s ca-dence of HMI (Helioseismic and Magnetic Imager) [2] and AIA (Atmospheric Imaging Assembly) [3] instruments of SDO. We have found a good relationship between the magnetic flux and coronal emissions. Here we discuss properties of the complexes in the different levels from photosphere to corona. References 1. W. Dean Pesnell, B.J. Thompson, P.C. Chamberlin // Solar Phys., v. 275, p. 3-15, (2012). 2. P.H. Scherrer, J. Schou, R.I. Bush et al. // Solar Phys., v. 275, p. 207-227, (2012). 3. James R. Lemen • Alan M. Title • David J. Akin et al. // Solar Phys., v. 275, p. 17-40, (2012).

  12. Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state

    DOE PAGES

    Abramowski, A.

    2011-09-01

    The high-frequency peaked BL Lac object PKS 2005-489 was the target of amulti-wavelength campaignwith simultaneous observations in the TeV γ-ray (H.E.S.S.), GeV γ-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E> 100 GeV) spectrum measured with H.E.S.S. with a peak energy between ~ 5 and 500 GeV. Compared to observations with contemporaneousmore » coverage in the VHE and X-ray bands in 2004, the X-ray flux was ~ 50 times higher during the 2009 campaign while the TeV γ-ray flux shows marginal variation over the years. The spectral energy distribution during this multi-wavelength campaign was fit by a one zone synchrotron self-Compton model with a well determined cutoff in X-rays. The parameters of a one zone SSC model are inconsistent with variability time scales. The variability behaviour over years with the large changes in synchrotron emission and small changes in the inverse Compton emission does not warrant an interpretation within a one-zone SSC model despite an apparently satisfying fit to the broadband data in 2009.« less

  13. Structure of vanadium oxide supported on ceria by multi-wavelength Raman spectroscopy

    SciTech Connect

    Wu, Zili; Rondinone, Adam Justin; Overbury, Steven {Steve} H

    2011-01-01

    ABSTRACT The structure of vanadium oxide species supported on ceria (VOx/CeO2) was investigated under various conditions by in situ multi-wavelength Raman spectroscopy, IR spectroscopy, isotopic labeling and temperature programmed reduction (TPR). For the first time, the detailed structure of dehydrated VOx species was revealed on the polycrystalline ceria support. VOx species can co-exist on ceria surface in the structure of monomer, dimer, trimer, polymer, crystalline V2O5 and CeVO4 as a function of VOx loading. These species interact strongly with both the defect sites and labile surface oxygen of ceria, passivating the redox property of ceria. Under ambient condition, the dispersed VOx species are hydrated into polyvanadate species which can be reversibly dehydrated back to the original structure forms. The ceria support with defect sites facilitates the interaction between water (H218O) and V16Ox species, leading to very facile isotopic oxygen exchange between the two even at room temperature. During H2 reduction, both the VOx species and the ceria support can be reduced with ceria surface being more reducible. The reducibility of various dispersed VOx species scales with their polymerization degree, i.e., polymer > trimer > dimer > monomer. The reoxidation of reduced VOx species is found to proceed via ceria lattice oxygen instead of the gas phase oxygen where ceria acts as an oxygen buffer. The revealed structure evolution of surface VOx species on ceria under hydrated, dehydrated, reduced, and regenerated conditions provides a basis for understanding the vanadia-ceria catalysis.

  14. A MULTI-WAVELENGTH STUDY OF STAR FORMATION ACTIVITY IN THE S235 COMPLEX

    SciTech Connect

    Dewangan, L. K.; Luna, A.; Mayya, Y. D.; Ojha, D. K.; Ninan, J. P.; Mallick, K. K.; Anandarao, B. G.

    2016-03-01

    We have carried out an extensive multi-wavelength study to investigate the star formation process in the S235 complex. The S235 complex has a spherelike shell appearance at wavelengths longer than 2 μm and harbors an O9.5V type star approximately at its center. A near-infrared extinction map of the complex traces eight subregions (having A{sub V} > 8 mag), and five of them appear to be distributed in an almost regularly spaced manner along the spherelike shell surrounding the ionized emission. This picture is also supported by the integrated {sup 12}CO and {sup 13}CO intensity maps and by Bolocam 1.1 mm continuum emission. The position–velocity analysis of CO reveals an almost semi-ringlike structure, suggesting an expanding H ii region. We find that the Bolocam clump masses increase as we move away from the location of the ionizing star. This correlation is seen only for those clumps that are distributed near the edges of the shell. Photometric analysis reveals 435 young stellar objects (YSOs), 59% of which are found in clusters. Six subregions (including five located near the edges of the shell) are very well correlated with the dust clumps, CO gas, and YSOs. The average values of Mach numbers derived using NH{sub 3} data for three (East 1, East 2, and Central E) out of these six subregions are 2.9, 2.3, and 2.9, indicating these subregions are supersonic. The molecular outflows are detected in these three subregions, further confirming the ongoing star formation activity. Together, all these results are interpreted as observational evidence of positive feedback of a massive star.

  15. Multi-wavelength dual polarisation lidar for monitoring precipitation process in the cloud seeding technique

    NASA Astrophysics Data System (ADS)

    Sudhakar, P.; Sheela, K. Anitha; Ramakrishna Rao, D.; Malladi, Satyanarayana

    2016-05-01

    In recent years weather modification activities are being pursued in many countries through cloud seeding techniques to facilitate the increased and timely precipitation from the clouds. In order to induce and accelerate the precipitation process clouds are artificially seeded with suitable materials like silver iodide, sodium chloride or other hygroscopic materials. The success of cloud seeding can be predicted with confidence if the precipitation process involving aerosol, the ice water balance, water vapor content and size of the seeding material in relation to aerosol in the cloud is monitored in real time and optimized. A project on the enhancement of rain fall through cloud seeding is being implemented jointly with Kerala State Electricity Board Ltd. Trivandrum, Kerala, India at the catchment areas of the reservoir of one of the Hydro electric projects. The dual polarization lidar is being used to monitor and measure the microphysical properties, the extinction coefficient, size distribution and related parameters of the clouds. The lidar makes use of the Mie, Rayleigh and Raman scattering techniques for the various measurement proposed. The measurements with the dual polarization lidar as above are being carried out in real time to obtain the various parameters during cloud seeding operations. In this paper we present the details of the multi-wavelength dual polarization lidar being used and the methodology to monitor the various cloud parameters involved in the precipitation process. The necessary retrieval algorithms for deriving the microphysical properties of clouds, aerosols characteristics and water vapor profiles are incorporated as a software package working under Lab-view for online and off line analysis. Details on the simulation studies and the theoretical model developed in this regard for the optimization of various parameters are discussed.

  16. A multi-wavelength survey of obscured and reddened quasars at the peak of galaxy formation

    NASA Astrophysics Data System (ADS)

    Alexandroff, Rachael

    2017-01-01

    While in the nearby universe the unification model seems firmly established, we are now seeing hints that at the peak of quasar activity and black hole growth (z~2.5) both obscured and reddened quasars may represent not just a specific quasar orientation but instead a unique stage of quasar evolution. Our group has developed several observational techniques to identify obscured and highly reddened quasars at z~2.5 using a combination of the SDSS spectroscopy and WISE photometry. Our sample contains objects with some of the most extreme ionized gas velocities observed (> 5000 km/s), indicating wind speeds too large to be contained by the galaxy potential though they are radio quiet. I will present both our sample selection and initial results from multi-wavelength follow-up of this sample using near-infrared spectroscopy, Keck spectropolarimentry and the VLA to test the AGN unification model and search for evidence of galaxy-wide quasar winds. High levels of polarized light (reaching ~20% of the total continuum emission in some cases) and changes in the polarization fraction and position angle across emission lines may argue for the presence of dusty outflows in our objects. This is supported by evidence from stacking analysis in the radio that presents a correlation between the observed outflow speeds in ionized gas (as measured by [OIII]) and the radio luminosity—arguing for a wind origin for the radio emission in these objects as well. The most extreme of these objects may thus represent the “blowout phase” of AGN evolution that proceeds or accompanies the cessation of star formation in the host galaxy due to the effects of radiatively-driven quasar driven winds.

  17. Lights and shadows: multi-wavelength analysis of young stellar objects and their protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Rigon, Laura

    2016-03-01

    Stars form from the collapse of molecular clouds and evolve in an environment rich in gas and dust before becoming Main Sequence stars. During this phase, characterised by the presence of a protoplanetary disc, stars manifest changes in the structure and luminosity. This thesis performs a multi-wavelength analysis, from optical to mm range, on a sample of young stars (YSOs), mainly Classical T Tauri (CTTS). The purpose is to study optical and infrared variability and its relation with the protoplanetary disc. Longer wavelength, in the mm range, are used instead to investigate the evolution of the disc, in terms of dust growth. In optical, an F-test on a sample of 39 CTTS reveals that 67% of the stars are variable. The variability, quantified through pooled sigma, is visible both in magnitude amplitudes and changes over time. Time series analysis applied on the more variable stars finds the presence of quasi periodicity, with periods longer than two weeks, interpreted either as eclipsing material in the disc happening on a non-regular basis, or as a consequence of star-disc interaction via magnetic field lines. The variability of YSOs is confirmed also in infrared, even if with lower amplitude. No strong correlations are found between optical and infrared variability, which implies a different cause or a time shift in the two events. By using a toy model to explore their origin, I find that infrared variations are likely to stem from emissions in the inner disc. The evolution of discs in terms of dust growth is confirmed in most discs by the analysis of the slope of the spectral energy distribution (SED), after correcting for wind emission and optical depth effects. However, the comparison with a radiative transfer model highlights that a number of disc parameters, in particular disc masses and temperature, dust size distribution and composition, can also affect the slope of the SED.

  18. Multi-wavelength View of Kiloparsec-scale Clumps in Star-forming Galaxies at z ~ 2

    NASA Astrophysics Data System (ADS)

    Guo, Yicheng; Giavalisco, Mauro; Ferguson, Henry C.; Cassata, Paolo; Koekemoer, Anton M.

    2012-10-01

    This paper studies the properties of kiloparsec-scale clumps in star-forming galaxies at z ~ 2 through multi-wavelength broadband photometry. A sample of 40 clumps is identified from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) z-band images through auto-detection and visual inspection from 10 galaxies with 1.5 < z < 2.5 in the Hubble Ultra Deep Field, where deep and high-resolution HST/WFC3 and ACS images enable us to resolve structures of z ~ 2 galaxies down to the kiloparsec scale in the rest-frame UV and optical bands and to detect clumps toward the faint end. The physical properties of clumps are measured through fitting spatially resolved seven-band (BVizYJH) spectral energy distribution to models. On average, the clumps are blue and have similar median rest-frame UV-optical color as the diffuse components of their host galaxies, but the clumps have large scatter in their colors. Although the star formation rate (SFR)-stellar mass relation of galaxies is dominated by the diffuse components, clumps emerge as regions with enhanced specific star formation rates, contributing individually ~10% and together ~50% of the SFR of the host galaxies. However, the contributions of clumps to the rest-frame UV/optical luminosity and stellar mass are smaller, typically a few percent individually and ~20% together. On average, clumps are younger by 0.2 dex and denser by a factor of eight than diffuse components. Clump properties have obvious radial variations in the sense that central clumps are redder, older, more extincted, denser, and less active on forming stars than outskirt clumps. Our results are broadly consistent with a widely held view that clumps are formed through gravitational instability in gas-rich turbulent disks and would eventually migrate toward galactic centers and coalesce into bulges. Roughly 40% of the galaxies in our sample contain a massive clump that could be identified as a proto-bulge, which seems qualitatively consistent with

  19. MULTI-WAVELENGTH VIEW OF KILOPARSEC-SCALE CLUMPS IN STAR-FORMING GALAXIES AT z {approx} 2

    SciTech Connect

    Guo Yicheng; Giavalisco, Mauro; Cassata, Paolo; Ferguson, Henry C.; Koekemoer, Anton M.

    2012-10-01

    This paper studies the properties of kiloparsec-scale clumps in star-forming galaxies at z {approx} 2 through multi-wavelength broadband photometry. A sample of 40 clumps is identified from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) z-band images through auto-detection and visual inspection from 10 galaxies with 1.5 < z < 2.5 in the Hubble Ultra Deep Field, where deep and high-resolution HST/WFC3 and ACS images enable us to resolve structures of z {approx} 2 galaxies down to the kiloparsec scale in the rest-frame UV and optical bands and to detect clumps toward the faint end. The physical properties of clumps are measured through fitting spatially resolved seven-band (BVizYJH) spectral energy distribution to models. On average, the clumps are blue and have similar median rest-frame UV-optical color as the diffuse components of their host galaxies, but the clumps have large scatter in their colors. Although the star formation rate (SFR)-stellar mass relation of galaxies is dominated by the diffuse components, clumps emerge as regions with enhanced specific star formation rates, contributing individually {approx}10% and together {approx}50% of the SFR of the host galaxies. However, the contributions of clumps to the rest-frame UV/optical luminosity and stellar mass are smaller, typically a few percent individually and {approx}20% together. On average, clumps are younger by 0.2 dex and denser by a factor of eight than diffuse components. Clump properties have obvious radial variations in the sense that central clumps are redder, older, more extincted, denser, and less active on forming stars than outskirt clumps. Our results are broadly consistent with a widely held view that clumps are formed through gravitational instability in gas-rich turbulent disks and would eventually migrate toward galactic centers and coalesce into bulges. Roughly 40% of the galaxies in our sample contain a massive clump that could be identified as a proto-bulge, which

  20. Measurement and correction of transverse chromatic offsets for multi-wavelength retinal microscopy in the living eye

    PubMed Central

    Harmening, Wolf M.; Tiruveedhula, Pavan; Roorda, Austin; Sincich, Lawrence C.

    2012-01-01

    A special challenge arises when pursuing multi-wavelength imaging of retinal tissue in vivo, because the eye’s optics must be used as the main focusing elements, and they introduce significant chromatic dispersion. Here we present an image-based method to measure and correct for the eye’s transverse chromatic aberrations rapidly, non-invasively, and with high precision. We validate the technique against hyperacute psychophysical performance and the standard chromatic human eye model. In vivo correction of chromatic dispersion will enable confocal multi-wavelength images of the living retina to be aligned, and allow targeted chromatic stimulation of the photoreceptor mosaic to be performed accurately with sub-cellular resolution. PMID:23024901

  1. Diode-end-pumped solid-state lasers with dual gain media for multi-wavelength emission

    NASA Astrophysics Data System (ADS)

    Cho, C. Y.; Chang, C. C.; Chen, Y. F.

    2015-01-01

    We develop a theoretical model for designing a compact efficient multi-wavelength laser with dual gain media in a shared resonator. The developed model can be used to analyze the optimal output reflectivity for each wavelength to achieve maximum output power for multi-wavelength emission. We further demonstrate a dual-wavelength laser at 946 nm and 1064 nm with Nd:YAG and Nd:YVO4 crystals to confirm the numerical analysis. Under optimum conditions and at incident pump power of 17 W, output power at 946 nm and 1064 nm was up to 2.51 W and 2.81 W, respectively.

  2. CANDELS MULTI-WAVELENGTH CATALOGS: SOURCE DETECTION AND PHOTOMETRY IN THE GOODS-SOUTH FIELD

    SciTech Connect

    Guo Yicheng; Barro, Guillermo; Faber, Sandra M.; Koo, David C.; Giavalisco, Mauro; Willner, S. P.; Ashby, Matthew L. N.; Donley, Jennifer L.; Fontana, Adriano; Galametz, Audrey; Grazian, Andrea; Kocevski, Dale D.; McGrath, Elizabeth J.; Peth, Michael; Salvato, Mara; Wuyts, Stijn; and others

    2013-08-15

    We present a UV to mid-infrared multi-wavelength catalog in the CANDELS/GOODS-S field, combining the newly obtained CANDELS HST/WFC3 F105W, F125W, and F160W data with existing public data. The catalog is based on source detection in the WFC3 F160W band. The F160W mosaic includes the data from CANDELS deep and wide observations as well as previous ERS and HUDF09 programs. The mosaic reaches a 5{sigma} limiting depth (within an aperture of radius 0.''17) of 27.4, 28.2, and 29.7 AB for CANDELS wide, deep, and HUDF regions, respectively. The catalog contains 34,930 sources with the representative 50% completeness reaching 25.9, 26.6, and 28.1 AB in the F160W band for the three regions. In addition to WFC3 bands, the catalog also includes data from UV (U band from both CTIO/MOSAIC and VLT/VIMOS), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), and infrared (HST/WFC3 F098M, VLT/ISAAC Ks, VLT/HAWK-I Ks, and Spitzer/IRAC 3.6, 4.5, 5.8, 8.0 {mu}m) observations. The catalog is validated via stellar colors, comparison with other published catalogs, zero-point offsets determined from the best-fit templates of the spectral energy distribution of spectroscopically observed objects, and the accuracy of photometric redshifts. The catalog is able to detect unreddened star-forming (passive) galaxies with stellar mass of 10{sup 10} M{sub Sun} at a 50% completeness level to z {approx} 3.4 (2.8), 4.6 (3.2), and 7.0 (4.2) in the three regions. As an example of application, the catalog is used to select both star-forming and passive galaxies at z {approx} 2-4 via the Balmer break. It is also used to study the color-magnitude diagram of galaxies at 0 < z < 4.

  3. Multi-wavelength seds of Herschel-selected galaxies in the cosmos field

    SciTech Connect

    Lee, Nicholas; Sanders, D. B.; Casey, Caitlin M.; Hung, Chao-Ling; Scoville, N. Z.; Capak, Peter; Bock, J.; Le Floc'h, Emeric; Aussel, Hervé; Ilbert, Olivier; Kartaltepe, Jeyhan S.; Roseboom, Isaac; Oliver, S. J.; Salvato, Mara; Aravena, M.; Berta, S.; Riguccini, L.; Symeonidis, M.

    2013-12-01

    We combine Herschel Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver maps of the full 2 deg{sup 2} Cosmic Evolution Survey (COSMOS) field with existing multi-wavelength data to obtain template and model-independent optical-to-far-infrared spectral energy distributions (SEDs) for 4218 Herschel-selected sources with log(L {sub IR}/L {sub ☉}) = 9.4-13.6 and z = 0.02-3.54. Median SEDs are created by binning the optical to far-infrared (FIR) bands available in COSMOS as a function of infrared luminosity. Herschel probes rest-frame wavelengths where the bulk of the infrared radiation is emitted, allowing us to more accurately determine fundamental dust properties of our sample of infrared luminous galaxies. We find that the SED peak wavelength (λ{sub peak}) decreases and the dust mass (M {sub dust}) increases with increasing total infrared luminosity (L {sub IR}). In the lowest infrared luminosity galaxies (log(L {sub IR}/L {sub ☉}) = 10.0-11.5), we see evidence of polycyclic aromatic hydrocarbon (PAH) features (λ ∼ 7-9 μm), while in the highest infrared luminosity galaxies (L {sub IR} > 10{sup 12} L {sub ☉}) we see an increasing contribution of hot dust and/or power-law emission, consistent with the presence of heating from an active galactic nucleus (AGN). We study the relationship between stellar mass and star formation rate of our sample of infrared luminous galaxies and find no evidence that Herschel-selected galaxies follow the SFR/M {sub *} 'main sequence' as previously determined from studies of optically selected, star-forming galaxies. Finally, we compare the mid-infrared to FIR properties of our infrared luminous galaxies using the previously defined diagnostic, IR8 ≡ L {sub IR}/L {sub 8}, and find that galaxies with L {sub IR} ≳ 10{sup 11.3} L {sub ☉} tend to systematically lie above (× 3-5) the IR8 'infrared main sequence', suggesting either suppressed PAH emission or an increasing contribution from

  4. Multi-wavelength SEDs of Herschel-selected Galaxies in the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Lee, Nicholas; Sanders, D. B.; Casey, Caitlin M.; Scoville, N. Z.; Hung, Chao-Ling; Le Floc'h, Emeric; Ilbert, Olivier; Aussel, Hervé; Capak, Peter; Kartaltepe, Jeyhan S.; Roseboom, Isaac; Salvato, Mara; Aravena, M.; Berta, S.; Bock, J.; Oliver, S. J.; Riguccini, L.; Symeonidis, M.

    2013-12-01

    We combine Herschel Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver maps of the full 2 deg2 Cosmic Evolution Survey (COSMOS) field with existing multi-wavelength data to obtain template and model-independent optical-to-far-infrared spectral energy distributions (SEDs) for 4218 Herschel-selected sources with log(L IR/L ⊙) = 9.4-13.6 and z = 0.02-3.54. Median SEDs are created by binning the optical to far-infrared (FIR) bands available in COSMOS as a function of infrared luminosity. Herschel probes rest-frame wavelengths where the bulk of the infrared radiation is emitted, allowing us to more accurately determine fundamental dust properties of our sample of infrared luminous galaxies. We find that the SED peak wavelength (λpeak) decreases and the dust mass (M dust) increases with increasing total infrared luminosity (L IR). In the lowest infrared luminosity galaxies (log(L IR/L ⊙) = 10.0-11.5), we see evidence of polycyclic aromatic hydrocarbon (PAH) features (λ ~ 7-9 μm), while in the highest infrared luminosity galaxies (L IR > 1012 L ⊙) we see an increasing contribution of hot dust and/or power-law emission, consistent with the presence of heating from an active galactic nucleus (AGN). We study the relationship between stellar mass and star formation rate of our sample of infrared luminous galaxies and find no evidence that Herschel-selected galaxies follow the SFR/M * "main sequence" as previously determined from studies of optically selected, star-forming galaxies. Finally, we compare the mid-infrared to FIR properties of our infrared luminous galaxies using the previously defined diagnostic, IR8 ≡ L IR/L 8, and find that galaxies with L IR >~ 1011.3 L ⊙ tend to systematically lie above (× 3-5) the IR8 "infrared main sequence," suggesting either suppressed PAH emission or an increasing contribution from AGN heating.

  5. CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field

    NASA Astrophysics Data System (ADS)

    Guo, Yicheng; Ferguson, Henry C.; Giavalisco, Mauro; Barro, Guillermo; Willner, S. P.; Ashby, Matthew L. N.; Dahlen, Tomas; Donley, Jennifer L.; Faber, Sandra M.; Fontana, Adriano; Galametz, Audrey; Grazian, Andrea; Huang, Kuang-Han; Kocevski, Dale D.; Koekemoer, Anton M.; Koo, David C.; McGrath, Elizabeth J.; Peth, Michael; Salvato, Mara; Wuyts, Stijn; Castellano, Marco; Cooray, Asantha R.; Dickinson, Mark E.; Dunlop, James S.; Fazio, G. G.; Gardner, Jonathan P.; Gawiser, Eric; Grogin, Norman A.; Hathi, Nimish P.; Hsu, Li-Ting; Lee, Kyoung-Soo; Lucas, Ray A.; Mobasher, Bahram; Nandra, Kirpal; Newman, Jeffery A.; van der Wel, Arjen

    2013-08-01

    We present a UV to mid-infrared multi-wavelength catalog in the CANDELS/GOODS-S field, combining the newly obtained CANDELS HST/WFC3 F105W, F125W, and F160W data with existing public data. The catalog is based on source detection in the WFC3 F160W band. The F160W mosaic includes the data from CANDELS deep and wide observations as well as previous ERS and HUDF09 programs. The mosaic reaches a 5σ limiting depth (within an aperture of radius 0.''17) of 27.4, 28.2, and 29.7 AB for CANDELS wide, deep, and HUDF regions, respectively. The catalog contains 34,930 sources with the representative 50% completeness reaching 25.9, 26.6, and 28.1 AB in the F160W band for the three regions. In addition to WFC3 bands, the catalog also includes data from UV (U band from both CTIO/MOSAIC and VLT/VIMOS), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), and infrared (HST/WFC3 F098M, VLT/ISAAC Ks, VLT/HAWK-I Ks, and Spitzer/IRAC 3.6, 4.5, 5.8, 8.0 μm) observations. The catalog is validated via stellar colors, comparison with other published catalogs, zero-point offsets determined from the best-fit templates of the spectral energy distribution of spectroscopically observed objects, and the accuracy of photometric redshifts. The catalog is able to detect unreddened star-forming (passive) galaxies with stellar mass of 1010 M ⊙ at a 50% completeness level to z ~ 3.4 (2.8), 4.6 (3.2), and 7.0 (4.2) in the three regions. As an example of application, the catalog is used to select both star-forming and passive galaxies at z ~ 2-4 via the Balmer break. It is also used to study the color-magnitude diagram of galaxies at 0 < z < 4.

  6. LIVAS: a 3-D multi-wavelength aerosol/cloud database based on CALIPSO and EARLINET

    NASA Astrophysics Data System (ADS)

    Amiridis, V.; Marinou, E.; Tsekeri, A.; Wandinger, U.; Schwarz, A.; Giannakaki, E.; Mamouri, R.; Kokkalis, P.; Binietoglou, I.; Solomos, S.; Herekakis, T.; Kazadzis, S.; Gerasopoulos, E.; Proestakis, E.; Kottas, M.; Balis, D.; Papayannis, A.; Kontoes, C.; Kourtidis, K.; Papagiannopoulos, N.; Mona, L.; Pappalardo, G.; Le Rille, O.; Ansmann, A.

    2015-07-01

    We present LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies), a 3-D multi-wavelength global aerosol and cloud optical database, optimized to be used for future space-based lidar end-to-end simulations of realistic atmospheric scenarios as well as retrieval algorithm testing activities. The LIVAS database provides averaged profiles of aerosol optical properties for the potential spaceborne laser operating wavelengths of 355, 532, 1064, 1570 and 2050 nm and of cloud optical properties at the wavelength of 532 nm. The global database is based on CALIPSO observations at 532 and 1064 nm and on aerosol-type-dependent backscatter- and extinction-related Ångström exponents, derived from EARLINET (European Aerosol Research Lidar Network) ground-based measurements for the UV and scattering calculations for the IR wavelengths, using a combination of input data from AERONET, suitable aerosol models and recent literature. The required spectral conversions are calculated for each of the CALIPSO aerosol types and are applied to CALIPSO backscatter and extinction data corresponding to the aerosol type retrieved by the CALIPSO aerosol classification scheme. A cloud optical database based on CALIPSO measurements at 532 nm is also provided, neglecting wavelength conversion due to approximately neutral scattering behavior of clouds along the spectral range of LIVAS. Averages of particle linear depolarization ratio profiles at 532 nm are provided as well. Finally, vertical distributions for a set of selected scenes of specific atmospheric phenomena (e.g., dust outbreaks, volcanic eruptions, wild fires, polar stratospheric clouds) are analyzed and spectrally converted so as to be used as case studies for spaceborne lidar performance assessments. The final global data set includes 4-year (1 January 2008-31 December 2011) time-averaged CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) data on a uniform grid of 1

  7. Multi-Wavelength Observations of Comet C/2011 L4 (PanSTARRS)

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Keane, J. V.; Meech, K. J.; Owen, T.; Wainscoat, R.

    2013-10-01

    Comet C/2011 L4 (PanSTARRS), which reached a visual magnitude brighter than 0 mag near its perihelion in March 2013, is one of the brightest comets since the great comet C/1995 O1 (Hale-Bopp). Discovered at 8AU from the Sun, the apparition of comet C/2011 L4 (PanSTARRS) provided a rare opportunity to monitor the dynamically new comet over a significant time period as well as a wide range of heliocentric distances. We will present our multi-wavelength observations of this dynamically new comet during its first in-bound leg from the Oort Cloud. A strong absorption band of water ice was detected at 2.0 microns in the moderate- to low-resolution spectra taken with 8-m Gemini-North and 3-m IRTF telescopes atop Mauna Kea, Hawaii. However, the companion 1.5 micron band of water ice was not observed. Our spectral models show that the weakened or absent 1.5 micron band can be explained by submicron-sized fine ice grains. Hindered by the weakness of the 1.5 micron feature, we were not able to constrain the crystallinity of the water ice particles in the coma of C/2011 L4. No gas emission (i.e. CN, HCN and CO) was observed pre-perihelion both in the optical and in the sub-millimeter using the 8-m Gemini-N and the 15-m JCMT telescopes. An estimated upper limit for CO production rate is at a level of 10^27 mol/sec when the comet was 3.44-2.31 AU from the Sun. The comet showed a very strong continuum in the optical that became redder as the comet approaching the Sun. Based on the Gemini optical spectroscopy, we calculated the Afρ quantity of this comet and found the value to be ~120 m. We further estimated the pre-perihelion dust production rate of ~650 kg/s which yielded a lower limit of the dust-to-gas ratio of 4. Our observations show that C/2011 L4 is a dust-rich/gas-poor comet. We will discuss the comparison between C/2011 L4 and other Oort Cloud comets.

  8. A multi-wavelength analysis of Hickson Compact Groups of galaxies

    NASA Astrophysics Data System (ADS)

    Bitsakis, T.; Charmandaris, V.

    2012-01-01

    We present a comprehensive study on the impact of the environment of compact galaxy groups on the evolution of their members using a multi-wavelength analysis, from the UV to the infrared, for a sample of 32 Hickson compact groups (HCGs) containing 135 galaxies. Fitting the SEDs of all galaxies with the state-of-the-art model of da Cunha (2008) we can accurately calculate their mass, SFR, and extinction, as well as estimate their infrared luminosity and dust content. We compare our findings with samples of field galaxies, early-stage interacting pairs, and cluster galaxies with similar data. We find that classifying the groups as dynamically "old" or "young", depending on whether or not at least one quarter of their members are early-type systems, is physical and consistent with past classifications of HCGs based on their atomic gas content. Dynamically "old" groups are more compact and display higher velocity dispersions than "young" groups. Late-type galaxies in dynamically "young" groups have specific star formation rates (sSFRs), NUV-r, and mid-infrared colors which are similar to those of field and early stage interacting pair spirals. Late-type galaxies in dynamically "old" groups have redder NUV-r colors, as they have likely experienced several tidal encounters in the past building up their stellar mass, and display lower sSFRs. We identify several late-type galaxies which have sSFRs and colors similar to those of elliptical galaxies, since they lost part of their gas due to numerous interactions with other group members. Also, 25% of the elliptical galaxies in these groups have bluer UV/optical colors than normal ellipticals in the field, probably due to star formation as they accreted gas from other galaxies of the group, or via merging of dwarf companions. Finally, our SED modeling suggests that in 13 groups, 10 of which are dynamically "old", there is diffuse cold dust in the intragroup medium. All this evidence point to an evolutionary scenario in which

  9. Mid-Infrared and multi-wavelength monitoring of the microquasar GRS 1915+105.

    NASA Astrophysics Data System (ADS)

    Fuchs, Yael; Chaty, Sylvain; Diana, Hannikainen; Mirabel, Felix; Rodriguez, Jerome

    2004-09-01

    We propose mid-infrared photometric and spectroscopic observations of the microquasar GRS 1915+105 in the context of a multi-wavelength follow-up campaign of the source. GRS 1915+105 is used as a laboratory to understand the accretion / ejection phenomena occurring in stellar-mass accreting black hole (microquasars) and by analogy in supermassive black holes (AGNs). A key question is the nature of the time-variable infrared emission in this system. Depending on the state of the source, we wish to know what is the contribution in the mid-infrared of the different possible emission mechanisms: the thermal emission from the K-M giant donor star, the synchrotron emission from the compact relativistic jets, X-ray reprocessing in the accretion disc and free-free emission from a dense wind. A particular contribution of the Spitzer Telescope will be the observation of this dense wind in GRS 1915+105, which is very difficult to detect in X-ray spectra due to pile-up phenomena in X-ray detectors. The continuum in a wavelength range as large as possible and the possible emission lines observed thanks to the Infrared Array Camera (IRAC) and the Infrared Spectrograph (IRS) are important clues to achieve this study. These mid-infrared observations will be combined with observations with the RXTE and INTEGRAL satellites in the X-rays and gamma-rays, the ESO/NTT in near-infrared and the Ryle Telescope in radio. Thanks to these simultaneous multiwavelength observations we will identify the accretion state of the source and determine the contribution of each emission component of the system. As GRS 1915+105 had been rarely observed in the mid-infrared range in the past, the Spitzer Space Telescope will bring the unique opportunity to do so, shedding light on the physical mechanisms occurring in this particular binary system and which could apply to the other black hole binaries.

  10. Multi-wavelength campaign on NGC 7469. I. The rich 640 ks RGS spectrum

    NASA Astrophysics Data System (ADS)

    Behar, Ehud; Peretz, Uria; Kriss, Gerard A.; Kaastra, Jelle; Arav, Nahum; Bianchi, Stefano; Branduardi-Raymont, Graziella; Cappi, Massimo; Costantini, Elisa; De Marco, Barbara; Di Gesu, Laura; Ebrero, Jacobo; Kaspi, Shai; Mehdipour, Missagh; Paltani, Stéphane; Petrucci, Pierre-Olivier; Ponti, Gabriele; Ursini, Francesco

    2017-05-01

    Aims: Outflows in active galaxies (AGNs) are common, although their launching mechanism, location, and physical impact on the host galaxy remain controversial. We conducted a multi-wavelength six-month campaign to observe the nearby Seyfert galaxy NGC 7469 with several observatories in order to better understand and quantify the outflow in this AGN. Methods: We report on the time-integrated line-resolved X-ray spectrum of NGC 7469 obtained with the Reflection Grating Spectrometer (RGS) on board XMM-Newton. We used the RGS spectrum to discern the many AGN outflow components and applied a global fit to obtain their physical parameters. Results: We find that the AGN wind can be well described by three narrow velocity components at -650, -950, and -2050 km s-1. The RGS clearly resolves the -2050 km s-1 component in C5+ Ly α, while the -650 km s-1 and -950 km s-1 velocities are blended. Similar velocities (±200 km s-1) are resolved in the UV. The H-equivalent column densities of these components are, respectively, NH 7 × 1020, 2.2 × 1021, and 1020 cm-2, for a total of 3 × 1021 cm-2, which was also measured in 2004, indicating the absorber did not significantly change. The -650 km s-1 component shows a broad ionization distribution (-1 ≲ log ξ ≲ 2,ξ being the ionization parameter in erg s-1 cm). We identify a photo-ionized emission component blue-shifted by -450 km s-1, somewhat broad (FWHM = 1400 km s-1), and with -1 ≲ log ξ ≲ 1 erg s-1 cm, which we ascribe to the same outflow that produces the absorption lines. We also find a collisionally ionized component at kT = 0.35 keV that we associate with the circum-nuclear star-formation activity of NGC 7469, as it follows the LFIR/LX ≈ 104 relation found in star forming galaxies. The elemental abundance ratios of C, N, Ne, S, and Fe to O in the outflow tend to be between one and two times solar. Preliminary estimates of the absorber distance from the AGN center suggest it is at least a few pc away from the

  11. A MULTI-WAVELENGTH VIEW OF THE STAR FORMATION ACTIVITY AT z {approx} 3

    SciTech Connect

    Magdis, G. E.; Elbaz, D.; Daddi, E.; Gobat, R.; Hwang, H. S.; Dickinson, M.; Rigopoulou, D.

    2010-05-10

    We present a multi-wavelength, UV-to-radio analysis for a sample of massive (M{sub *} {approx} 10{sup 10} M{sub sun}) IRAC- and MIPS 24 {mu}m detected Lyman break galaxies (LBGs) with spectroscopic redshifts z {approx} 3 in the GOODS-North field. For LBGs without individual 24 {mu}m detections, we employ stacking techniques at 24 {mu}m, 1.1 mm, and 1.4 GHz to construct the average UV-to-radio spectral energy distribution and find it to be consistent with that of a luminous infrared galaxy with L{sub IR} = 4.5{sup +1.1}{sub -2.3} x 10{sup 11} L{sub sun} and a specific star formation rate of 4.3 Gyr{sup -1} that corresponds to a mass doubling time {approx}230 Myr. On the other hand, when considering the 24 {mu}m detected LBGs we find among them galaxies with L{sub IR}>10{sup 12} L{sub sun}, indicating that the space density of z {approx} 3 UV-selected ultra-luminous infrared galaxies (ULIRGs) is {approx}(1.5 {+-} 0.5) x 10{sup -5} Mpc{sup -3}. We compare measurements of star formation rates from data at different wavelengths and find that there is tight correlation (Kendall's {tau}>99.7%) and excellent agreement between the values derived from dust-corrected UV, mid-IR, millimeter, and radio data for the whole range of L{sub IR} up to L{sub IR} {approx} 10{sup 13} L{sub sun}. This range is greater than that for which the correlation is known to hold at z {approx} 2, possibly due to the lack of significant contribution from polycyclic aromatic hydrocarbons to the 24 {mu}m flux at z {approx} 3. The fact that this agreement is observed for galaxies with L{sub IR}>10{sup 12} L{sub sun} suggests that star formation in UV-selected ULIRGs, as well as the bulk of star formation activity at this redshift, is not embedded in optically thick regions as seen in local ULIRGs and submillimeter-selected galaxies at z = 2.

  12. Gamma-Ray Bursts and Afterglows: a Multi-Wavelength Study in the Swift Era

    NASA Astrophysics Data System (ADS)

    Yu, Y. W.

    2010-01-01

    Gamma-ray bursts (GRBs), which are generally followed by long-lasting low-frequency afterglow emission, are short and intense pulses of gamma-rays observed from the sky in arbitrary directions. In order to observe the multi-wavelength emission at the early afterglow phase and even the prompt emission phase, NASA launched the Swift satellite on Nov. 20th 2004. Swift can localize GRBs within about 10 seconds. A brief review on the recent progress in observations and theories in the Swift era is given in Chapter 1. This paper focuses on the features of the early afterglows and the multi-wavelength prompt emission. In Chapters 2 and 3, we try to explain the shallow-decaying X-ray afterglows and X-ray flares, both of which are unaccountable in the standard afterglow model. (1) It is widely accepted that the shallow decay phase indicates a continuous energy injection into the GRB blast wave, and this energy could be released from the central engine after the burst. Based on the knowledge of the evolution of a pulsar wind, we argue that the injected flow interacting with the GRB blast wave is an ultra-relativistic kinetic-energy flow (i.e., wind) rather than pure electromagnetic waves. Therefore, a relativistic wind bubble (RWB) including a pair of shocks will be formed. Our numerical calculations and the fitting results show that the emission from an RWB can well account for the X-ray shallow decay phase. (2) For the X-ray flares that are attributed to some intermediate late activities of the central engine, we analyze the detailed dynamics of late internal shocks which directly produce the flare emission. Comparing the theoretical results with the lower limits of the observational luminosities and the profiles of the flare light curves, we find some constraints on the properties of the pre-collision shells, which are directly determined by the central object. In Chapter 4, we investigate the high-energy afterglow emission during the shallow decay phase in two models, i

  13. Stable power multi-wavelength fibre laser based on four-wave mixing in a short length of highly non-linear fibre

    NASA Astrophysics Data System (ADS)

    Awang, N. A.; Zulkifli, M. Z.; Latif, A. A.; Harun, S. W.; Ahmad, H.

    2011-07-01

    A multi-wavelength fibre laser utilizing the four-wave mixing (FWM) effect in a 100 m long highly non-linear fibre (HNLF) is proposed and demonstrated. The multi-wavelength fibre laser is configured in a ring cavity and only needs a low power erbium doped fibre amplifier (EDFA) as the gain medium to generate 11 lines in the range of 1582-1600 nm with a signal-to-noise ratio (SNR) of 43 dB. The proposed system is very stable, with only minor fluctuations of 0.1 dB in the output power of the generated multi-wavelengths observed for a test period of more than an hour. The multi-wavelength fibre laser has many potential applications in optical communications and optical sensing systems.

  14. Combining near-field hyperspectral imaging and far-field spectral-angular distribution to develop mid-field white LED optical models with spatial color deviation.

    PubMed

    Lee, Tsung-Xian; Lu, Tsung-Lin; Chen, Bo-Song

    2016-07-11

    The integration of spatial distribution of light intensity and color in the midfield is instrumental for LED optical design. On the basis of this rationale, we proposed an accurate and convenient method for developing white LED optical models. Near-field hyperspectral images and far-field spectral-angular distributions were integrated to illustrate changes in spatial light intensity and color distribution in the mid-field, to the exclusion of the absorption, conversion, and scattering of phosphors. The corresponding optical models were developed for three LED samples under different packaging conditions. Their normalized cross-correlation values for spatial light intensity and correlated-color-temperature distribution between simulation and measurement averaged as high as 0.995 and 0.99 respectively, which validated the accuracy and feasibility of the proposed method.

  15. Multi-wavelength and High-resolution Observations of Solar Eruptive Activities

    NASA Astrophysics Data System (ADS)

    Shen, Y. D.

    2014-09-01

    In recent years, various solar eruptive activities have been observed in the solar atmosphere, such as solar flares, filament eruptions, jets, coronal mass ejections (CMEs), and magnetohydrodynamics (MHD) waves. Previous observations have indicated that solar magnetic field plays a dominant role in the processes of all kinds of solar activities. Since many large-scale solar eruptive activities can cause significant effects on the space environment of the Earth as well as the human life, studying and forecasting the solar activities are urgent tasks for us. In addition, the Sun is the nearest star to the Earth, so that people can directly observe and study it in detail. Hence, studying the Sun can also provide a reference to study other stars in the universe. This thesis focuses on the multi-wavelength and high-resolution observations of three types of solar eruptive activities: filament eruptions, coronal jets, and coronal MHD waves. By analyzing various observations taken by ground-based and space-borne instruments, we try to understand the inherent physical mechanisms, and construct models to interpret different kinds of solar eruptive activities. The triggering mechanism and the cause of a failed filament eruption are studied in Chapter 3, which indicates that the energy released in the flare is a key factor to the fate of the filament. Two successive filament eruptions are studied in Chapter 4, which indicates that the magnetic implosion could be the physical linkage between them, and the structures of coronal magnetic fields are important for producing sympathetic eruptions. A magnetic unwinding jet and a blowout jet are studied in Chapters 5 and 6, respectively. The former exhibits obvious radial expansion, which undergoes three distinct phases: the slow expansion phase, the fast expansion phase, and the steady phase. In addition, calculation indicates that the non-potential magnetic field in the jet can supply sufficient energy for producing the unwinding

  16. Multi-Wavelength Observations On The Gamma-Ray Blazar PG1553+113 As A Probe For Geometrical Periodical Modulation

    NASA Astrophysics Data System (ADS)

    Stamerra, Antonio; Prandini, E.; Paiano, S.; Da Vela, P.; Gareth, H.; Covino, S.; Cutini, S.; Sandrinelli, A.; Sobacchi, E.; Sormani, M. C.

    2016-10-01

    New claims of periodic variability from gamma-ray blazars have been reported, possibly pointing at milli-pc SMBH binary systems. A modulation of 2 year on 3.5 cycles was recently discovered with Fermi/LAT on the blazar PG1553+113 - for the first time in gamma-rays with high significance - and confirmed by optical lightcurves. Other possible gamma-ray periodic variations have been claimed on PKS 2155-304 and PKS 0537 by Sandrinelli et al. (2015, 2016). The interpretation of such periodicity, when confirmed with continuous observations in following years, is not straightforward. Emission from blazars is dominated by non-thermal emission from the jet; different processes in the jet or at its base, may lead to quasi-periodic emission. We used multi-wavelength (MWL) observations on PG1553+113 to investigate if the observed modulation can be explained with geometrical variations in the jet, possibly pointing to jet precession or to an helical pattern. The ongoing MWL monitoring campaign from radio to very-high energy gamma-ray bands, led by the MAGIC collaboration, will follow the maximum expected at the beginning of 2017, and will allow to set tighter constrains on underlying periodic processes.

  17. Study on the Multi-wavelength Emissivity of GCr15 Steel and its Application on Temperature Measurement for Continuous Casting Billets

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Xie, Zhi; Hu, Zhenwei

    2016-12-01

    A method for measuring the multi-wavelength emissivity of a steel surface is proposed, and an applicable experimental apparatus is designed. Multi-wavelength radiant energy emitted from a sample was measured using a fiber-optic spectrometer and its temperature measured using a NiCrSi/NiSiMg thermocouple. Utilizing the unique vacuum control and background noise-shielding systems, we investigated the multi-wavelength emissivity of GCr15 steel at three different degrees of surface oxidation at temperatures ranging from 1000°C to 1100°C. The experimental results show that the multi-wavelength (0.7 μ m-0.9 μ m) emissivity increased substantially, from 0.409-0.565 to 0.609-0.702, once the steel was oxidized. In addition, the emissivity increased slightly with increasing temperature, but the trends for emissivity and wavelength were similar. To measure the surface temperature of casting billets based on multi-wavelength thermometry, the functional relationships between emissivity and wavelength at different extents of oxidation were determined. Temperature measurements based on our technique were compared with those from common colorimetric thermometry. Our approach reduced the temperature fluctuation from ± 23°C to ± 3.5°C, indicating that a reliable measurement of the multi-wavelength emissivity of GCr15 steel is obtained using this experimental apparatus.

  18. A multi-wavelength optical sender/receiver for an internet access system configured on passive optical network

    NASA Astrophysics Data System (ADS)

    Yasui, Tadahiko; Nakata, Takayuki; Matsuda, Hironari

    2006-09-01

    The authors have developed a multi-wavelength IP packet sender/receiver to be inserted into a PCI-bus slot of a PC or a workstation. When the workstations or PCs with the sender/receivers are connected to an internet access network configured on the PON as client terminals, a pee-to-peer connection-oriented communication path can be set up between them. The PCs can afford a real-time interactive communication with QoS fully guaranteed.

  19. A multi-wavelength (u.v. to visible) laser system for early detection of oral cancer

    NASA Astrophysics Data System (ADS)

    Najda, S. P.; Perlin, P.; Leszczyński, M.; Slight, T. J.; Meredith, W.; Schemmann, M.; Moseley, H.; Woods, J. A.; Valentine, R.; Kalra, S.; Mossey, P.; Theaker, E.; Macluskey, M.; Mimnagh, G.; Mimnagh, W.

    2015-03-01

    A multi-wavelength (360nm - 440nm), real-time Photonic Cancer Detector (PCD) optical system based on GaN semiconductor laser technology is outlined. A proof of concept using blue laser technology for early detection of cancer has already been tested and proven for esophageal cancer. This concept is expanded to consider a wider range of wavelengths and the PCD will initially be used for early diagnosis of oral cancers. The PCD creates an image of the oral cavity (broad field white light detection) and maps within the oral cavity any suspicious lesions with high sensitivity using a narrow field tunable detector.

  20. A Multi-Wavelength Approach to Quasar Variability: New Insights Into Their Physics, Evolution, and Selection Effects

    NASA Astrophysics Data System (ADS)

    Djorgovski, Stanislav

    merger phase. "Discoveries of a number of distinct subpopulation of quasars showing unusual or extreme variability patents, including: “Major long-duration flare events, some, but not all of which may be related to a new population of ultraluminous SNe from the accretion disks, or some heretofore unknown energetic phenomena associated with the active nuclei. “Changing spectroscopic type (e.g., from type 1 to type 2) AGN, which may result from the changes in obscuration along the line of sight, and/or the luminosity changes from the central engine. Variability also offers a spectrum-independent method for quasar discovery that bypasses many selection effects, and thus a test of the completeness of the existing samples. Combining the variability-based and spectrum-based selection criteria would lead to more complete samples of quasars that would affect our understanding of their phenomenology and evolution. We propose to combine multi-wavelength and multi-epoch data sets from a variety of missions, from mid-IR to gamma-ray, supplemented with multicolor optical, NIR, and radio surveys from the ground in order to further explore and interpret these findings and use them to provide new observational constraints

  1. Parallel online multi-wavelength (2D) fluorescence spectroscopy in each well of a continuously shaken microtiter plate.

    PubMed

    Ladner, Tobias; Beckers, Mario; Hitzmann, Bernd; Büchs, Jochen

    2016-12-01

    Small-scale high-throughput screening devices are becoming increasingly important in bioprocess development. Conventional dipping probes for process monitoring are often too large to be used in these devices. Thus, optical measurements are often the method of choice. Even some parameters that cannot directly be measured by fluorescence become accessible via sensitive fluorescence dyes. However, not all compounds of interest are measurable by this technique. Recent studies applying multi-wavelength (2D) fluorescence spectroscopy in combination with chemometrics have shown that information on numerous analytes is obscured by the fluorescence data. Hitherto, this measurement technique has only been available on the scale of stirred tank fermenters. This work introduces a new device for multi-wavelength (2D) fluorescence spectroscopy in each well of a continuously shaken microtiter plate. Using a combination of spectrograph and CCD detector, the required time per measurement cycle in a 48-well microtiter plate was 0.5 h. Cultures of Hansenula polymorpha and Escherichia coli are monitored. The concentrations of glycerol, glucose and acetate as well as pH are determined using partial least square (PLS) models. Because a pH-sensitive fluorescence dye was not required, no dependency of the pKa of a fluorescence dye exists, and measurements in the low pH range can be obtained.

  2. A Study of Massive Star Evolution and Mass Loss With Multi-Wavelength Observations of Type IIn Supernovae

    NASA Astrophysics Data System (ADS)

    Fox, Ori; Skrutskie, Michael; Chevalier, Roger; Smith, Nathan; Chandra, Poonam; Filippenko, Alex

    2012-12-01

    Type IIn supernovae (SNe IIn) are a rare (<10%) subclass of SNe that exhibit narrow emission lines due to a dense, pre-existing circumstellar medium (CSM). Although all evidence points to massive star progenitors, the precise stellar type remains elusive since few observed stars and no theoretical models can reproduce the mass-loss characteristics. More confusing, the narrow lines and dense winds associated with SNe IIn have now been identified in an unexpectedly diverse list of subclasses, suggesting multiple progenitors may be responsible. Multi-wavelength observations, spanning the X-ray to the infrared (IR) to the radio regime, can probe various aspects of shock interaction and dust formation associated with the dense CSM for months to years after the radioactive emission fades. Such diagnostics probe the progenitor mass-loss history, CSM characteristics, and even the elusive SN shock breakout. Given the required coordination amongst space-based and large ground-based telescopes, however, existing data sets are sparse and insufficient. Here we submit a joint Spitzer/Chandra proposal to trace the mass-loss history of SNe IIn with a thorough, coordinated, multi-wavelength approach. With guaranteed time on Keck and JVLA already at our disposal and an aligned team of SNe IIn experts spanning all wavelengths, now is the time for such a program.

  3. AGLITE: a multi-wavelength lidar for measuring emitted aerosol concentrations and fluxes and air motion from agricultural facilities

    NASA Astrophysics Data System (ADS)

    Wilkerson, Thomas D.; Bingham, Gail E.; Zavyalov, Vladimir V.; Swasey, Jason A.; Hancock, Jed J.; Crowther, Blake G.; Cornelsen, Scott S.; Marchant, Christian; Cutts, James N.; Huish, David C.; Earl, Curtis L.; Andersen, Jan M.; Cox, McLain L.

    2006-12-01

    AGLITE is a multi-wavelength lidar developed for the Agricultural Research Service (ARS), United States Department of Agriculture (USDA) and its program on particle emissions from animal production facilities. The lidar transmitter is a 10 kHz pulsed NdYAG laser at 355, 532 and 1064 nm. We analyze lidar backscatter and extinction to extract aerosol physical properties. All-reflective optics and dichroic and interferometric filters permit all wavelengths to be measured simultaneously, day or night, using photon counting by MTs, an APD, and fast data acquisition. The lidar housing is a transportable trailer suitable for all-weather operation at any accessible site. We direct the laser and telescope FOVs to targets of interest in both azimuth and elevation. The lidar has been applied in atmospheric studies at a swine production farm in Iowa and a dairy in Utah. Prominent aerosol plumes emitted from the swine facility were measured as functions of temperature, turbulence, stability and the animal feed cycle. Particle samplers and turbulence detectors were used by colleagues specializing in those fields. Lidar measurements also focused on air motion as seen by scans of the farm volume. The value of multi-wavelength, eye-safe lidars for agricultural aerosol measurements has been confirmed by the successful operation of AGLITE.

  4. Simultaneous multi-wavelength phase-shifting interferometry based on principal component analysis with a color CMOS

    NASA Astrophysics Data System (ADS)

    Fan, Jingping; Lu, Xiaoxu; Xu, Xiaofei; Zhong, Liyun

    2016-05-01

    From a sequence of simultaneous multi-wavelength phase-shifting interferograms (SMWPSIs) recorded by a color CMOS, a principal component analysis (PCA) based multi-wavelength interferometry (MWI) is proposed. First, a sequence of SMWPSIs with unknown phase shifts are recorded with a single-chip color CMOS camera. Subsequently, the wrapped phases of single-wavelength are retrieved with the PCA algorithm. Finally, the unambiguous phase of the extended synthetic wavelength is achieved by the subtraction between the wrapped phases of single-wavelength. In addition, to eliminate the additional phase introduced by the microscope and intensity crosstalk among three-color channels, a two-step phase compensation method with and without the measured object in the experimental system is employed. Compared with conventional single-wavelength phase-shifting interferometry, due to no requirements for phase shifts calibration and the phase unwrapping operation, the actual unambiguous phase of the measured object can be achieved with the proposed PCA-based MWI method conveniently. Both numerical simulations and experimental results demonstrate that the proposed PCA-based MWI method can enlarge not only the measuring range, but also no amplification of noise level.

  5. A Multi-Wavelength Opto-Electronic Patch Sensor to Effectively Detect Physiological Changes against Human Skin Types.

    PubMed

    Yan, Liangwen; Hu, Sijung; Alzahrani, Abdullah; Alharbi, Samah; Blanos, Panagiotis

    2017-06-21

    Different skin pigments among various ethnic group people have an impact on spectrometric illumination on skin surface. To effectively capture photoplethysmographic (PPG) signals, a multi-wavelength opto-electronic patch sensor (OEPS) together with a schematic architecture of electronics were developed to overcome the drawback of present PPG sensor. To perform a better in vivo physiological measurement against skin pigments, optimal illuminations in OEPS, whose wavelength is compatible with a specific skin type, were optimized to capture a reliable physiological sign of heart rate (HR). A protocol was designed to investigate an impact of five skin types in compliance with Von Luschan's chromatic scale. Thirty-three healthy male subjects between the ages of 18 and 41 were involved in the protocol implemented by means of the OEPS system. The results show that there is no significant difference (p: 0.09, F = 3.0) in five group tests with the skin types across various activities throughout a series of consistent measurements. The outcome of the present study demonstrates that the OEPS, with its multi-wavelength illumination characteristics, could open a path in multiple applications of different ethnic groups with cost-effective health monitoring.

  6. Monolithically integrated multi-wavelength MQW-DBR laser diodes fabricated by selective metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Sasaki, Tatsuya; Yamaguchi, Masayuki; Kitamura, Mitsuhiro

    1994-12-01

    Selective metalorganic vapor phase epitaxy (MOVPE) was used to grow InGaAsP/InP layers for fabricating multi-wavelength laser diodes. Multiple quantum well (MQW) active and passive waveguides were simultaneously grown by one step selective growth. The selectively grown layer thickness increases with the mask stripe width. This growth enhancement can be used to control the lasing wavelength of distributed Bragg reflector (DBR) laser diodes, because the effective refractive index of the MQW passive waveguide at the DBR region can be controlled by the mask stripe width. This simple technique was used to fabricate multi-wavelength MQW-DBR laser diodes. In the selective growth, the MQW structure was grown under 150 Torr to obtain large bandgap energy shift for the MQW passive waveguides compared to the active waveguide, which was effective for wide wavelength tuning range. On the contrary, a bulk InGaAsP guide layer was grown under 35 Torr to prevent too much composition shift and maintain high crystalline quality of the MQW passive waveguide. For 10 consecutive laser diodes, a wavelength span of over 20 nm with accurate wavelength control was achieved.

  7. Single Brillouin frequency shifted S-band multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier in ring cavity

    NASA Astrophysics Data System (ADS)

    Reshak, A. H.; Hambali, N. A. M. Ahmad; Shahimin, M. M.; Wahid, M. H. A.; Anwar, Nur Elina; Alahmed, Zeyad A.; Chyský, J.

    2016-10-01

    This paper is focusing on simulation and analyzing of S-band multi-wavelength Brillouin-Raman fiber laser performance utilizing fiber Bragg grating and Raman amplifier in ring cavity. Raman amplifier-average power model is employed for signal amplification. This laser system is operates in S-band wavelength region due to vast demanding on transmitting the information. Multi-wavelength fiber lasers based on hybrid Brillouin-Raman gain configuration supported by Raman scattering effect have attracted significant research interest due to its ability to produced multi-wavelength signals from a single light source. In multi-wavelength Brillouin-Raman fiber, single mode fiber is utilized as the nonlinear gain medium. From output results, 90% output coupling ratio has ability to provide the maximum average output power of 43 dBm at Brillouin pump power of 20 dBm and Raman pump power of 14 dBm. Furthermore, multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier is capable of generated 7 Brillouin Stokes signals at 1480 nm, 1510 nm and 1530 nm.

  8. A multi-wavelength erbium-doped fiber ring laser using an intrinsic Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Jauregui-Vazquez, D.; Rojas-Laguna, R.; Estudillo-Ayala, J. M.; Hernandez-Garcia, J. C.; Lopez-Dieguez, Y.; Sierra-Hernandez, J. M.

    2016-10-01

    In this experimental paper, a multi-wavelength erbium-doped ring fiber laser based on an all fiber intrinsic Fabry-Perot interferometer is presented and demonstrated. The interferometer was fabricated by an arc and splicing technique using hollow core photonic crystal fiber (HCPCF) and conventional single mode fiber (SMF28). The fiber laser can be operated in single, dual and triple lasing mode by applying a transversal load over the all fiber interferometer. The laser spectrums present minimal mode spacing of 1 nm, high wavelength stability and power fluctuations around 0.5 dB. The average signal to noise ratio (SNR) of the laser emissions spectrum is around 35 dB. This fiber laser offers low cost, compactness and high wavelength stability.

  9. Mode-locking and Q-switching in multi-wavelength fiber ring laser using low frequency phase modulation.

    PubMed

    Jun, Chang Su; Kim, Byoung Yoon

    2011-03-28

    We describe experimental investigation of pulsed output from a multi-wavelength fiber ring laser incorporating low frequency phase modulation with large modulation amplitude. The Erbium-doped fiber (EDF) ring laser generated more than 8 wavelength channels with the help of a phase modulator operating at 26.2 kHz and a periodic intra-cavity filter. For most cases, the laser output is pulsed in the form of mode-locking at 5.62 MHz and/or Q-switching at harmonic and sub-harmonic of the phase modulation frequency. Chaotic pulse output is also observed. The behavior of the output pulses are described as functions of pump power and phase modulation amplitude. The relative intensity noise (RIN) value of a single wavelength channel is measured to be under -100 dB/Hz (-140 dB/Hz beyond 1.5 GHz).

  10. Multi-wavelength Observations Of The Psr B1259-63/ Ss 2883 Be Star Periastron In 2010

    NASA Astrophysics Data System (ADS)

    Abdo, Aous; Fermi LAT Collaboration; Johnston, S.; Grundstrom, E.; Roberts, M.

    2011-01-01

    PSR B1259-63/SS 2883 is a unique binary system consisting of a 47.7 ms radio pulsar orbiting a massive (10 - 15 M⊙) Be companion star. The pulsar orbits the companion star with a period of 3.4 years in a highly eccentric orbit. We have scheduled a coordinated radio, IR, optical, X-ray, and GeV gamma-ray observing campaign for the December 2010 periastron passage. This is the first periastron since the launch of the Fermi Gamma-ray Space Telescope and thus provides for the first time the opportunity to observe the passage of the source through the Be stellar disk at GeV energies with such a sensitive instrument. We will present results from our multi-wavelength campaign.

  11. A compact, multi-wavelength, and high frequency response light source for diffuse optical spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Park, Kyoungsu; Lee, Minseok; Lee, Seung-ha; Cerussi, Albert E.; Chung, Phil-sang; Kim, Sehwan

    2015-03-01

    Many biomedical applications require an efficient combination and localization of multiple discrete light sources. In this paper, we present a compact six-channel combiner of optical sub-assembly type that couples the output of independent solid-state light sources into a single 400 μm diameter optical fiber. It is equipped with six discrete laser diodes, 658, 690, 705, 785, 830, and 850 nm for the measurement of the tissue optical properties from optical spectroscopy and imaging. We demonstrate coupling efficiencies ≥ 77% and output optical power ≥ 20 mW for each of the 6 laser diodes installed into the prototype. The design supports the use of continuous wave and intensity modulated laser diodes (with bandwidth ≥ 3 GHz). The developed light source could be used to construct custom multi-wavelength sources for tissue oximeters, diffuse optical imaging, and molecular imaging technologies.

  12. Multi-wavelength pulsars study : Long-term timing of XMM, HESS and GLAST sources with the Nancay radiotelescope

    NASA Astrophysics Data System (ADS)

    Theureau, G.; Cognard, I.; Smith, D.; Webb, N.; Gallant, Y.

    2006-06-01

    We present here the current Nançay observing program gathering the pulsar french community around the radio follow-up of X- and gamma-ray pulsars for the building of a complete multi-wavelength sample. The goal of this project is double : 1) provide strong constraints on the physics and emission mechanisms of pulsars , 2) guarantee the success of pulsar harvest at high energy by providing good and contemporaneous ephemerides for folding the few gamma and X-ray photons . The community is well involved in the last generation of gamma-ray and X-ray detectors and the availability of the NRT and its dedicated backend BON represents a very good opportunity for acquiring the necessary and complementary radio data.

  13. Improved quantitative phase imaging in lensless microscopy by single-shot multi-wavelength illumination using a fast convergence algorithm.

    PubMed

    Sanz, Martín; Picazo-Bueno, José Angel; García, Javier; Micó, Vicente

    2015-08-10

    We report on a novel algorithm for high-resolution quantitative phase imaging in a new concept of lensless holographic microscope based on single-shot multi-wavelength illumination. This new microscope layout, reported by Noom et al. along the past year and named by us as MISHELF (initials incoming from Multi-Illumination Single-Holographic-Exposure Lensless Fresnel) microscopy, rises from the simultaneous illumination and recording of multiple diffraction patterns in the Fresnel domain. In combination with a novel and fast iterative phase retrieval algorithm, MISHELF microscopy is capable of high-resolution (micron range) phase-retrieved (twin image elimination) biological imaging of dynamic events. In this contribution, MISHELF microscopy is demonstrated through qualitative concept description, algorithm implementation, and experimental validation using both a synthetic object (resolution test target) and a biological sample (swine sperm sample) for the case of three (RGB) illumination wavelengths. The proposed method becomes in an alternative instrument improving the capabilities of existing lensless microscopes.

  14. Galaxy Formation in Action: A Multi-Wavelength Study of Ly-alpha Nebulae in the Distant Universe

    NASA Astrophysics Data System (ADS)

    Zabludoff, Ann I.

    2012-01-01

    Lyman-alpha blobs are mysterious objects in the distant Universe extending over 50-100 kpc. Because these gigantic gas clouds have been detected only in optically thick and highly resonant Lyman-alpha emission, their power source remains a puzzle. Due to the rarity of blobs, the form of their evolution to the present day is also unknown. We are conducting multi-wavelength, deep, and large area surveys to identify tens of blobs at redshifts 2-5. These surveys have now produced the first constraints on blob clustering, showing that blobs occupy massive halos likely to evolve into rich clusters today. Blobs are not only tracers of the most overdense environments at early times, but also may mark the sites of brightest cluster galaxy formation. By targeting the optically-thin lines such as Halpha, we have obtained the first measurements of gas kinematics in blobs, excluding strong outflows as the source of Lyman-alpha emission.

  15. A screening method of oil-soluble synthetic dyes in chilli products based on multi-wavelength chromatographic fingerprints comparison.

    PubMed

    Zhu, Yonghong; Wu, Yanlei; Zhou, Chunjie; Zhao, Bo; Yun, Wen; Huang, Siyu; Tao, Peng; Tu, Dawei; Chen, Shiqi

    2016-02-01

    A multi-wavelength HPLC fingerprint comparison method was proposed for the screening of oil-soluble synthetic dyes in chilli products. The screening was based on the fingerprint differences of normal unadulterated chilli sample with tested chilli samples. The samples were extracted with acetone and fingerprinted by HPLC under four visible light wavelengths (450 nm, 490 nm, 520 nm, and 620 nm). It was found that the fingerprints of different chilli product samples had a relatively fixed number of peaks and stable retention time. When 16 kinds of known synthetic dyes were used as model analytes to assess the screening efficiency, 14 of them could be screened using fingerprint comparison method, with LOD of 0.40-2.41 mg/kg. The new screening method was simple and had the possibility of finding existence of the adulterated dyes which could not be identified using known standard analytes as control. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. MODELING MULTI-WAVELENGTH STELLAR ASTROMETRY. III. DETERMINATION OF THE ABSOLUTE MASSES OF EXOPLANETS AND THEIR HOST STARS

    SciTech Connect

    Coughlin, J. L.; Lopez-Morales, Mercedes

    2012-05-10

    Astrometric measurements of stellar systems are becoming significantly more precise and common, with many ground- and space-based instruments and missions approaching 1 {mu}as precision. We examine the multi-wavelength astrometric orbits of exoplanetary systems via both analytical formulae and numerical modeling. Exoplanets have a combination of reflected and thermally emitted light that causes the photocenter of the system to shift increasingly farther away from the host star with increasing wavelength. We find that, if observed at long enough wavelengths, the planet can dominate the astrometric motion of the system, and thus it is possible to directly measure the orbits of both the planet and star, and thus directly determine the physical masses of the star and planet, using multi-wavelength astrometry. In general, this technique works best for, though is certainly not limited to, systems that have large, high-mass stars and large, low-mass planets, which is a unique parameter space not covered by other exoplanet characterization techniques. Exoplanets that happen to transit their host star present unique cases where the physical radii of the planet and star can be directly determined via astrometry alone. Planetary albedos and day-night contrast ratios may also be probed via this technique due to the unique signature they impart on the observed astrometric orbits. We develop a tool to examine the prospects for near-term detection of this effect, and give examples of some exoplanets that appear to be good targets for detection in the K to N infrared observing bands, if the required precision can be achieved.

  17. Characterization of forest fire smoke event near Washington, DC in summer 2013 with multi-wavelength lidar

    NASA Astrophysics Data System (ADS)

    Veselovskii, I.; Whiteman, D. N.; Korenskiy, M.; Suvorina, A.; Kolgotin, A.; Lyapustin, A.; Wang, Y.; Chin, M.; Bian, H.; Kucsera, T. L.; Pérez-Ramírez, D.; Holben, B.

    2015-02-01

    The multi-wavelength lidar technique was applied to the study of a smoke event near Washington, DC on 26-28 August 2013. Satellite observations combined with transport model predictions imply that the smoke plume originated mainly from Wyoming/Idaho forest fires and its transportation to Washington, DC took approximately 5 days. The NASA Goddard Space Flight Center (GSFC) multi-wavelength Mie-Raman lidar was used to measure the smoke particle intensive parameters such as extinction and backscatter Ångström exponents together with lidar ratios at 355 and 532 nm wavelengths. For interpretation of the observed vertical profiles of the backscatter Ångström exponents γβ at 355-532 and 532-1064 nm, numerical simulation was performed. The results indicate that, for fine-mode dominant aerosols, the Ångström exponents γβ(355-532) and γβ(532-1064) have essentially different dependence on the particle size and refractive index. Inversion of 3 β + 2 α lidar observations on 27-28 August provided vertical variation of the particle volume, effective radius and the real part of the refractive index through the planetary boundary layer (PBL) and the smoke layer. The particle effective radius decreased with height from approximately 0.27 μm inside the PBL to 0.15 μm in the smoke layer, which was situated above the PBL. Simultaneously the real part of the refractive index in the smoke layer increased to mR ≈ 1.5. The retrievals demonstrate also that the fine mode is predominant in the particle size distribution, and that the decrease of the effective radius with height is due to a shift of the fine mode toward smaller radii.

  18. CMOS buried quad p-n junction photodetector for multi-wavelength analysis.

    PubMed

    Richard, Charles; Courcier, Thierry; Pittet, Patrick; Martel, Stéphane; Ouellet, Luc; Lu, Guo-Neng; Aimez, Vincent; Charette, Paul G

    2012-01-30

    This paper presents a buried quad p-n junction (BQJ) photodetector fabricated with a HV (high-voltage) CMOS process. Multiple buried junction photodetectors are wavelength-sensitive devices developed for spectral analysis applications where a compact integrated solution is preferred over systems involving bulk optics or a spectrometer due to physical size limitations. The BQJ device presented here is designed for chip-based biochemical analyses using simultaneous fluorescence labeling of multiple analytes such as with advanced labs-on-chip or miniaturized photonics-based biosensors. Modeling and experimental measurements of the spectral response of the device are presented. A matrix-based method for estimating individual spectral components in a compound spectrum is described. The device and analysis method are validated via a test setup using individually modulated LEDs to simulate light from 4-component fluorescence emission.

  19. X-Ray and Multi-Wavelength Observations of Gamma Ray Bursts (GRBs)

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2009-01-01

    The launch of the Italian (with Dutch participation) satellite BeppoSAX in 1996 enabled the detection of the first X-ray GRB afterglow, which in turn led to GRB counterpart detection in multiple wavelengths. This breakthrough firmly established the cosmological nature of GRBs. However, afterglow observations of GRBs took off in large numbers after the launch of NASA's Swift satellite in 2004. Swift enabled multiple major discoveries, such as the early lightcurves of X-ray afterglows, the first detection of a short GRB afterglow and opened more questions such as where are the elusive breaks in afterglow light curves. I will describe here these results and will discuss future opportunities and improvements in the field.

  20. Multi-wavelength laser sensor surface for high frame rate imaging refractometry (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kristensen, Anders; Vannahme, Christoph; Sørensen, Kristian T.; Dufva, Martin

    2016-09-01

    A highly sensitive distributed feedback (DFB) dye laser sensor for high frame rate imaging refractometry without moving parts is presented. The laser sensor surface comprises areas of different grating periods. Imaging in two dimensions of space is enabled by analyzing laser light from all areas in parallel with an imaging spectrometer. Refractive index imaging of a 2 mm by 2 mm surface is demonstrated with a spatial resolution of 10 μm, a detection limit of 8 10-6 RIU, and a framerate of 12 Hz, limited by the CCD camera. Label-free imaging of dissolution dynamics is demonstrated.

  1. Electro- and thermo-optic effects on multi-wavelength Solc filters based on chi(2) nonlinear quasi-periodic photonic crystals.

    PubMed

    Kee, Chul-Sik; Lee, Yeong Lak; Lee, Jongmin

    2008-04-28

    We investigate electro- and thermo-optic effects on multi-wavelength Solc filters based on chi(2) nonlinear quasi-periodic photonic crystals. The multi-wavelength Solc filters are composed of two building blocks A and B, in which each containing a pair of antiparallel poled domains, arranged as a Fibonacci sequence. The transmittances at filtering wavelengths can be modulated from 0 to 100% by applying an external voltage but the filtering wave-lengths are unchanged. The filtering wavelengths can be tuned by varying temperature. As temperature decreases, the filtering wavelengths increase (approximately -0.45 nm/degrees C).

  2. Multi-wavelength reflection spectra from an acousto-optic modulated fiber Bragg grating in a highly birefringent suspended core fiber

    NASA Astrophysics Data System (ADS)

    Silva, Ricardo E.; Becker, Martin; Rothhardt, Manfred; Bartelt, Hartmut; Pohl, Alexandre A. P.

    2017-04-01

    The interaction of a fiber Bragg grating and longitudinal acoustic waves in a highly birefringent suspended-core fiber is investigated for the realization of a multi-wavelength reflection property. The modulated grating couples power from the fast and slow polarization modes to shifted superposed modes supported by the grating. The grating reflectivity of the superposed modes are tuned by the voltage of an electrical signal. Up to five different wavelength reflection peaks have been generated indicating new possibilities for compact and fast fiber-integrated multi-wavelength dynamic filters.

  3. A CR-HYDRO-NEI MODEL OF MULTI-WAVELENGTH EMISSION FROM THE VELA JR. SUPERNOVA REMNANT (SNR RX J0852.0-4622)

    SciTech Connect

    Lee, Shiu-Hang; Nagataki, Shigehiro; Slane, Patrick O.; Patnaude, Daniel J.; Ellison, Donald C. E-mail: nagataki@yukawa.kyoto-u.ac.jp E-mail: dpatnaude@cfa.harvard.edu

    2013-04-10

    Based largely on energy budget considerations and the observed cosmic-ray (CR) ionic composition, supernova remnant (SNR) blast waves are the most likely sources of CR ions with energies at least up to the 'knee' near 10{sup 15} eV. Shocks in young shell-type TeV-bright SNRs are surely producing TeV particles, but the emission could be dominated by ions producing {pi}{sup 0}-decay emission or electrons producing inverse Compton gamma rays. Unambiguously identifying the GeV-TeV emission process in a particular SNR will not only help pin down the origin of CRs, it will also add significantly to our understanding of the diffusive shock acceleration (DSA) mechanism and improve our understanding of supernovae and the impact SNRs have on the circumstellar medium. In this study, we investigate the Vela Jr. SNR, an example of TeV-bright non-thermal SNRs. We perform hydrodynamic simulations coupled with nonlinear DSA and non-equilibrium ionization near the forward shock to confront currently available multi-wavelength data. We find, with an analysis similar to that used earlier for SNR RX J1713.7-3946, that self-consistently modeling the thermal X-ray line emission with the non-thermal continuum in our one-dimensional model strongly constrains the fitting parameters, and this leads convincingly to a leptonic origin for the GeV-TeV emission for Vela Jr. This conclusion is further supported by applying additional constraints from observation, including the radial brightness profiles of the SNR shell in TeV gamma rays, and the spatial variation of the X-ray synchrotron spectral index. We will discuss implications of our models on future observations by the next-generation telescopes.

  4. A compact multi-wavelength optoacoustic system based on high-power diode lasers for characterization of double-walled carbon nanotubes (DWCNTs) for biomedical applications

    NASA Astrophysics Data System (ADS)

    Leggio, Luca; de Varona, Omar; Escudero, Pedro; Carpintero del Barrio, Guillermo; Osiński, Marek; Lamela Rivera, Horacio

    2015-06-01

    During the last decade, Optoacoustic Imaging (OAI), or Optoacoustic Tomography (OAT), has evolved as a novel imaging technique based on the generation of ultrasound waves with laser light. OAI may become a valid alternative to techniques currently used for the detection of diseases at their early stages. It has been shown that OAI combines the high contrast of optical imaging techniques with high spatial resolution of ultrasound systems in deep tissues. In this way, the use of nontoxic biodegradable contrast agents that mark the presence of diseases in near-infrared (NIR) wavelengths range (0.75-1.4 um) has been considered. The presence of carcinomas and harmful microorganisms can be revealed by means of the fluorescence effect exhibited by biopolymer nanoparticles. A different approach is to use carbon nanotubes (CNTs) which are a contrast agent in NIR range due to their absorption characteristics in the range between 800 to 1200 nm. We report a multi-wavelength (870 and 905 nm) laser diode-based optoacoustic (OA) system generating ultrasound signals from a double-walled carbon nanotubes (DWCNTs) solution arranged inside a tissue-like phantom, mimicking the scattering of a biological soft tissue. Optoacoustic signals obtained with DWCNTs inclusions within a tissue-like phantom are compared with the case of ink-filled inclusions, with the aim to assess their absorption. These measurements are done at both 870 and 905 nm, by using high power laser diodes as light sources. The results show that the absorption is relatively high when the inclusion is filled with ink and appreciable with DWCNTs.

  5. Multi-Wavelength, Multi-Beam, and Polarization-Sensitive Laser Transmitter for Surface Mapping

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Ramos-Izquierdo, Luis; Harding, David; Huss, Tim

    2011-01-01

    A multi-beam, multi-color, polarized laser transmitter has been developed for mapping applications. It uses commercial off-the-shelf components for a lowcost approach for a ruggedized laser suitable for field deployment. The laser transmitter design is capable of delivering dual wavelengths, multiple beams on each wavelength with equal (or variable) intensities per beam, and a welldefined state of polarization. This laser transmitter has been flown on several airborne campaigns for the Slope Imaging Multi-Polarization Photon Counting Lidar (SIMPL) instrument, and at the time of this reporting is at a technology readiness level of between 5 and 6. The laser is a 1,064-nm microchip high-repetition-rate laser emitting energy of about 8 microjoules per pulse. The beam was frequency-doubled to 532 nm using a KTP (KTiOPO4) nonlinear crystal [other nonlinear crystals such as LBO (LiB3O5) or periodically poled lithium niobiate can be used as well, depending on the conversion efficiency requirements], and the conversion efficiency was approximately 30 percent. The KTP was under temperature control using a thermoelectric cooler and a feedback monitoring thermistor. The dual-wavelength beams were then spectrally separated and each color went through its own optical path, which consisted of a beam-shaping lens, quarterwave plate (QWP), and a birefringent crystal (in this case, a calcite crystal, but others such as vanadate can be used). The QWP and calcite crystal set was used to convert the laser beams from a linearly polarized state to circularly polarized light, which when injected into a calcite crystal, will spatially separate the circularly polarized light into the two linear polarized components. The spatial separation of the two linearly polarized components is determined by the length of the crystal. A second set of QWP and calcite then further separated the two beams into four. Additional sets of QWP and calcite can be used to further split the beams into multiple

  6. A Multi-Wavelength Study of the X-Ray Sources in the NGC 5018

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Swartz, Douglas A.; Tennant, Allyn F.; Wu, Kinwah; Saripalli, Lakshmi

    2004-01-01

    The E3 giant elliptical galaxy NGC-5018 was observed with the cxo X-ray Observatory's Advanced CCD Imaging Spectrometer for 30-h on 14 April 2001. Results of analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point sources, including the nucleus, were detected. If they are intrinsic to NGC-5018, then all six non-nuclear sources have luminosities exceeding 10(exp 39)-ergl in the 0.5-8.0-keV energy band; placing them in the class of Ultra- luminous X-ray sources. Comparison of X-ray source positions to archival Hubble Space Telescope/Wide Field Planetary Camera 2 (hst/WFPC2) images reveal four of the six non-nuclear sources are spatially--coincident with bright, M$(sub V)LA -8.6 mag, objects. These four objects have optical magnitudes and (V-I) colors consistent with globular clusters in NGC-5018. However, one of these objects was observed to vary by siml mag in both V and I between observations taken 28 July 1997 and 04 Feb 1999 indicating this source is a background active galactic nucleus (AGN). The nature of the other three optically-bright objects cannot be determined from the available optical data but all have X-ray-to-optical flux ratios consistent with background AGNs. Strong, unpolarized, radio emission has been detected from another of the optically-bright counterparts. It displays an inverted radio spectrum and is the most absorbed of the seven sources in the X-ray band. It, too, is most readily explained as a background AGN, though alternative explanations cannot be ruled out. Extended X-ray emission is detected within a siml5 arcsec radius of the galaxy center at a luminosity of sim lO(exp 40)-ergl in the X-ray band. Its thermal X-ray spectrum (kT sim0.4-keV) and its spatial coincidence with strong H(alpha) emission are consistent with a hot gas origin. The nucleus itself is a weak X-ray source, LA-5 times 10(exp 39)-ergl, but displays a radio spectrum typical of AGN.

  7. A Multi-Wavelength Study of the X-Ray Sources in the NGC 5018

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Swartz, Douglas A.; Tennant, Allyn F.; Wu, Kinwah; Saripalli, Lakshmi

    2004-01-01

    The E3 giant elliptical galaxy NGC-5018 was observed with the cxo X-ray Observatory's Advanced CCD Imaging Spectrometer for 30-h on 14 April 2001. Results of analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point sources, including the nucleus, were detected. If they are intrinsic to NGC-5018, then all six non-nuclear sources have luminosities exceeding 10(exp 39)-ergl in the 0.5-8.0-keV energy band; placing them in the class of Ultra- luminous X-ray sources. Comparison of X-ray source positions to archival Hubble Space Telescope/Wide Field Planetary Camera 2 (hst/WFPC2) images reveal four of the six non-nuclear sources are spatially--coincident with bright, M$(sub V)LA -8.6 mag, objects. These four objects have optical magnitudes and (V-I) colors consistent with globular clusters in NGC-5018. However, one of these objects was observed to vary by siml mag in both V and I between observations taken 28 July 1997 and 04 Feb 1999 indicating this source is a background active galactic nucleus (AGN). The nature of the other three optically-bright objects cannot be determined from the available optical data but all have X-ray-to-optical flux ratios consistent with background AGNs. Strong, unpolarized, radio emission has been detected from another of the optically-bright counterparts. It displays an inverted radio spectrum and is the most absorbed of the seven sources in the X-ray band. It, too, is most readily explained as a background AGN, though alternative explanations cannot be ruled out. Extended X-ray emission is detected within a siml5 arcsec radius of the galaxy center at a luminosity of sim lO(exp 40)-ergl in the X-ray band. Its thermal X-ray spectrum (kT sim0.4-keV) and its spatial coincidence with strong H(alpha) emission are consistent with a hot gas origin. The nucleus itself is a weak X-ray source, LA-5 times 10(exp 39)-ergl, but displays a radio spectrum typical of AGN.

  8. Performance Analysis of Multi-Wavelength Transmission Scanner for Polarized NIR Light

    NASA Astrophysics Data System (ADS)

    Atroshchenko, K.; Fontana, C. L.; De Rosa, M.; Bello, M.; Moschini, G.; Uzunov, N. M.; Rossi, P.

    2012-12-01

    A system for small-object imaging, comprising a multiple-wavelength scanner for Near Infra-Red (NIR) light is under development in the Laboratory of Radiopharmaceuticals and Molecular Imaging (LRMI) at the National Laboratories of Legnaro, INFN, Italy. The System performs scanning of biological objects using NIR light in the interval of 900nm - 1700nm. The scanned region is a rectangular with dimensions of 50mm × 80mm and is performed by consecutive positioning of InGaAs linear image sensor sliding close to the scanned object. The scanning is carried out in two different modes. The first mode is performed in transmitted linearly polarized NIR light using a set of five light emitting diodes with fixed wavelengths. The process of scanning is realized by a consecutive positioning of the NIR sensor and signal acquisition at the corresponding position. In the second scanning mode the fluorescence emission of nanoparticles such as single-walled carbon nanotubes (SWCNTs), administered in the imaged object, is excited by NIR lasers with different wavelengths. Spatial resolution of the system for transmitted linearly polarized NIR at five fixed wavelengths has been determined. Polarimetric measurements of some optically active sugars such as fructose and lactose were conducted at some fixed wavelengths in the range of 900-1200nm. The system sensitivity with respect to the concentrations of these agents has been estimated.

  9. Color-filter-free spatial visible light communication using RGB-LED and mobile-phone camera.

    PubMed

    Chen, Shih-Hao; Chow, Chi-Wai

    2014-12-15

    A novel color-filter-free visible-light communication (VLC) system using red-green-blue (RGB) light emitting diode (LED) and mobile-phone camera is proposed and demonstrated for the first time. A feature matching method, which is based on the scale-invariant feature transform (SIFT) algorithm for the received grayscale image is used instead of the chromatic information decoding method. The proposed method is simple and saves the computation complexity. The signal processing is based on the grayscale image computation; hence neither color-filter nor chromatic channel information is required. A proof-of-concept experiment is performed and high performance channel recognition is achieved.

  10. Supermassive Black Holes in Bulgeless and Dwarf Galaxies: A Multi-Wavelength Investigation

    NASA Astrophysics Data System (ADS)

    Secrest, Nathan J.

    Supermassive black holes (SMBHs) are now understood to reside at the centers of nearly all major galaxies in the Universe. From studies of high-redshift quasars, we understand that SMBHs formed very early in the Universe's history, and well-studied correlations between other properties of galaxies, such as their morphologies, star formation rate, and merger history, with their central SMBH shows that SMBHs played a key role in the evolution of galaxies. The fact that the post-Big Bang Universe was extremely uniform and homogeneous presents a major mystery: How did SMBHs millions to billions of times as massive as the Sun form in such a short time? Given the theoretical limit at which a black hole can accrete material, it is not plausible that SMBHs could have formed through the conventional route: the end stage of the lifecycle of a massive star. Rather, there are two major theories for the formation of SMBHs, each with its own prediction for the black hole mass distribution and occupation fraction in the local Universe. Understanding this mass distribution and occupation fraction is therefore imperative to understanding the formation of SMBHs, the quasars that reveal their presence in the early Universe, and ultimately the evolution of galaxies to the present day. While large SMBHs in major, bulge-dominated galaxies are relatively easy to detect and characterize, this population of SMBHs is understood to have been built up largely through black hole merger events that erase any information about the progenitor black holes' masses. We must therefore search for SMBHs in late-type, bulgeless, and dwarf galaxies, which are much more likely to have had a relatively quiet, merger-free history, in order to glimpse the properties of the `seed' black holes that led to the buildup of SMBHs during the earliest epoch of the Universe. In this thesis, I will discuss my contributions to the understanding of this question, as well as what questions remain to be answered and the

  11. MULTI-WAVELENGTH PROBES OF OBSCURATION TOWARD THE NARROW-LINE REGION IN SEYFERT GALAXIES

    SciTech Connect

    Kraemer, S. B.; Schmitt, H.R.; Crenshaw, D. M.; Melendez, M.; Turner, T.J.; Guainazzi, M.; Mushotzky, R.F.

    2011-02-01

    We present a study of reddening and absorption toward the narrow line regions (NLRs) in active galactic nuclei (AGNs) selected from the Revised Shapley-Ames, 12 {mu}m, and Swift/Burst Alert Telescope samples. For the sources in host galaxies with inclinations of b/a > 0.5, we find that the mean ratio of [O III] {lambda}5007, from ground-based observations, and [O IV] 28.59 {mu}m, from Spitzer/Infrared Spectrograph observations, is a factor of two lower in Seyfert 2s than Seyfert 1s. The combination of low [O III]/[O IV] and [O III] {lambda}4363/{lambda}5007 ratios in Seyfert 2s suggests more extinction of emission from the NLR than in Seyfert 1s. Similar column densities of dusty gas, N{sub H}{approx} several x 10{sup 21} cm{sup -2}, can account for the suppression of both [O III] {lambda}5007 and [O III] {lambda}4363, as compared to those observed in Seyfert 1s. Also, we find that the X-ray line O VII {lambda}22.1 A is weaker in Seyfert 2s, consistent with absorption by the same gas that reddens the optical emission. Using a Hubble Space Telescope/Space Telescope Imaging Spectrograph slitless spectrum of the Seyfert 1 galaxy NGC 4151, we estimate that only {approx}30% of the [O III] {lambda}5007 comes from within 30 pc of the central source, which is insufficient to account for the low [O III]/[O IV] ratios in Seyfert 2s. If Seyfert 2 galaxies have similar intrinsic [O III] spatial profiles, the external dusty gas must extend further out along the NLR, perhaps in the form of nuclear dust spirals that have been associated with fueling flows toward the AGN.

  12. A time-resolved multi-wavelength fluorescence diffuse optical tomography system for small animal imaging

    NASA Astrophysics Data System (ADS)

    Montcel, Bruno; Chabrier, Renee; Poulet, Patrick

    2005-08-01

    A tomographic approach, relying on diffuse near infrared photons to image the optical properties of tissues and the inner distribution of fluorescent probes is described. The method should improve the spatial resolution and quantification of fluorescence signals, thanks to multiple-projection acquisitions and to a reconstruction procedure using the principles of diffuse optical tomography. The scanner assembled uses picosecond laser diodes, an eight-anode photo-multiplier tube (PMT) and time-correlated single photon counting. Two sets of laser heads, each operating at four wavelengths, are fitted with furcated optical fibers, providing two sequential sources of light positioned on the animal or object studied. Multimode optical fibers are used to detect light at eight output points on the animal or object. These fibers are connected to the PMT, with an air-gap allowing the insertion of an optical filter to reject the excitation wavelength. The light sources and detectors can be rotated to increase the number of projections recorded. For the reconstruction process, the coordinates of the body surface of the animal to be imaged are necessary. These are acquired by interferometry, using a conoscope and an XY scanning system, before the animal is entered in the scanner. The profiles measured at the excitation wavelengths are used to compute absorption and reduced scattering images and perfusion/oxygenation images of the animal. Fluorescence images, free from diffusion and absorption artefacts, can then be computed with a-priori knowledge of the optical images of the animal. The scanner, its performances and images of light-scattering and fluorescent phantoms are presented.

  13. Multi-wavelength Observations of a Subarcsecond Penumbral Transient Brightening Event

    NASA Astrophysics Data System (ADS)

    Bai, X. Y.; Su, J. T.; Cao, W. D.; Liu, S. Q.; Deng, Y. Y.; Priya, T. G.

    2016-05-01

    We report a subarcsecond penumbral transient brightening event with the high-spatial resolution observations from the 1.6 m New Solar Telescope (NST), Interface Region Imaging Spectrograph (IRIS), and the Solar Dynamics Observatory. The transient brightening, whose thermal energy is in the range of nanoflares, has signatures in the chromosphere, the transient region, and the corona. NST's Hα channel reveals the fine structure of the event with a width as narrow as 101 km (0.″14), which is much smaller than the width from the previous observation. The transient brightening lasts for about 3 minutes. It is associated with a redshift of about 17 km s-1, found in the Si iv 1402.77 Å line and exhibits an inward motion to the umbra with a speed of 87 km s-1. The small-scale energy released from the event has a multi-temperature component. Spectral analysis of the brightening region from IRIS shows that not only the transition region lines such as Si iv 1402.77 Å and C ii 1334.53 Å, but also the chromospheric Mg ii k 2796.35 Å line are significantly enhanced and broadened. In addition, the event can be found in all the extreme-ultraviolet passbands of the Atmospheric Imaging Assembly and the derived differential emission measure profile increases between 4 and 15 MK (or 6.6 ≤ log T ≤ 7.2) in the transient brightening phase. It is possible that the penumbral transient brightening event is caused by magnetic reconnection.

  14. A Multi-wavelength Analysis of Active Regions and Sunspots by Comparison of Automatic Detection Algorithms

    NASA Astrophysics Data System (ADS)

    Verbeeck, C.; Higgins, P. A.; Colak, T.; Watson, F. T.; Delouille, V.; Mampaey, B.; Qahwaji, R.

    2013-03-01

    Since the Solar Dynamics Observatory (SDO) began recording ≈ 1 TB of data per day, there has been an increased need to automatically extract features and events for further analysis. Here we compare the overall detection performance, correlations between extracted properties, and usability for feature tracking of four solar feature-detection algorithms: the Solar Monitor Active Region Tracker ( SMART) detects active regions in line-of-sight magnetograms; the Automated Solar Activity Prediction code ( ASAP) detects sunspots and pores in white-light continuum images; the Sunspot Tracking And Recognition Algorithm ( STARA) detects sunspots in white-light continuum images; the Spatial Possibilistic Clustering Algorithm ( SPoCA) automatically segments solar EUV images into active regions (AR), coronal holes (CH), and quiet Sun (QS). One month of data from the Solar and Heliospheric Observatory (SOHO)/ Michelson Doppler Imager (MDI) and SOHO/ Extreme Ultraviolet Imaging Telescope (EIT) instruments during 12 May - 23 June 2003 is analysed. The overall detection performance of each algorithm is benchmarked against National Oceanic and Atmospheric Administration (NOAA) and Solar Influences Data Analysis Center (SIDC) catalogues using various feature properties such as total sunspot area, which shows good agreement, and the number of features detected, which shows poor agreement. Principal Component Analysis indicates a clear distinction between photospheric properties, which are highly correlated to the first component and account for 52.86% of variability in the data set, and coronal properties, which are moderately correlated to both the first and second principal components. Finally, case studies of NOAA 10377 and 10365 are conducted to determine algorithm stability for tracking the evolution of individual features. We find that magnetic flux and total sunspot area are the best indicators of active-region emergence. Additionally, for NOAA 10365, it is shown that the

  15. A Multi-wavelength Study of Nearby Galaxies Based on Molecular Line Surveys: MIPS Observations

    NASA Astrophysics Data System (ADS)

    Fazio, Giovanni; Wang, Zhong; Bush, Stephanie; Cox, Thomas J.; Keto, Eric; Pahre, Michael; Rosolowsky, Erik; Smith, Howard

    2008-03-01

    Dense molecular gas, warm dust, and hot ionized gas are different components of the multi-step transformation of cold gas into stars and star clusters. While empirical laws on star formation in galaxies have been established based on global measurements of these components, substantial galaxy-to-galaxy variations still exist and remain unexplained. To understand the mechanisms that induce and regulate star formation and thus galaxy evolution, we need to study processes on the local scales of typical star forming regions and giant molecular clouds. In a set of pilot studies, we analyzed the Spitzer and Galex data of nearby giant spirals M31, M33 and M99, and compared with the new interferometric CO maps of matching angular resolution. We found evidence that variations in local condition, environmental effects, and viewing geometry may explain much of the large scatter in the empirical relationships. Based on the success of this initial investigation, we have collected high- resolution CO images of 63 late-type galaxies from several large surveys, and we are working on obtaining a complete set of Spitzer and Galex data for these galaxies. A companion Spitzer archival research program will re-examine the existing observations along with CO, HI, UV and optical data, focusing on correlations in spatially resolved, individual star-forming regions. Here we propose MIPS imaging of the 11 galaxies in our CO sample that have not already been observed by Spitzer. A GO proposal will request IRAC time for these galaxies, which are a significant addition to our study because they substantially increase the fraction of gas-rich late types in the full sample. Insight from this program will be applicable to not only nearby system, but also high red-shift galaxies for which only integrated quantities are measurable.

  16. Multi-wavelength analysis of supernova remnant MSH11-61A.

    NASA Astrophysics Data System (ADS)

    Auchettl, Katie; Slane, Patrick; Castro, Daniel

    MSH11-61A (G290.1-0.8) has been identified as a mixed morphology supernova remnant (SNR) from its centrally bright X-ray morphology and limb brightened radio profile. The evolutionary sequence which leads to these unusual X-ray properties is not well understood and currently different models can only explain some of the features seen in individual cases. In this analysis we present a study of MSH 11-61A using archival Suzaku data. Our preliminary results indicate enhanced abundances, as previously suggested by ASCA observations and we derive the associated age, energy and ambient density conditions of the remnant using models that we constructed in an attempt to reproduce the observed X-ray properties. Observational evidence from thermal and non-thermal emission of SNRs has provided increasing support in favour of cosmic rays being accelerated at the shock front of the remnant. Whether the observed gamma-ray emission from these accelerated CRs is hadronic or leptonic in nature is currently a hotly debated topic in the literature. SNRs known to be interacting with molecular clouds provide effective targets for detecting and studying gamma-rays. As MSH11-61A is thought to be interacting with a molecular cloud towards the south west of the remnant, we perform a spatial and spectral analysis of the gamma-ray emission in the region of this remnant by using ~64 months of data from the Fermi-LAT telescope. This analysis allows us to constrain the origin of the detected gamma-ray emission.

  17. MODELING MULTI-WAVELENGTH STELLAR ASTROMETRY. II. DETERMINING ABSOLUTE INCLINATIONS, GRAVITY-DARKENING COEFFICIENTS, AND SPOT PARAMETERS OF SINGLE STARS WITH SIM LITE

    SciTech Connect

    Coughlin, Jeffrey L.; Harrison, Thomas E.; Gelino, Dawn M.

    2010-11-10

    We present a novel technique to determine the absolute inclination of single stars using multi-wavelength submilliarcsecond astrometry. The technique exploits the effect of gravity darkening, which causes a wavelength-dependent astrometric displacement parallel to a star's projected rotation axis. We find that this effect is clearly detectable using SIM Lite for various giant stars and rapid rotators, and present detailed models for multiple systems using the REFLUX code. We also explore the multi-wavelength astrometric reflex motion induced by spots on single stars. We find that it should be possible to determine spot size, relative temperature, and some positional information for both giant and nearby main-sequence stars utilizing multi-wavelength SIM Lite data. These data will be extremely useful in stellar and exoplanet astrophysics, as well as supporting the primary SIM Lite mission through proper multi-wavelength calibration of the giant star astrometric reference frame, and reduction of noise introduced by starspots when searching for extrasolar planets.

  18. Multi-wavelength speckle reduction for laser pico-projectors using diffractive optics

    NASA Astrophysics Data System (ADS)

    Thomas, Weston H.

    Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser's stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a

  19. Multi-wavelength, Multi-scale Observations of Outflows in Star-Forming Regions

    NASA Astrophysics Data System (ADS)

    Plunkett, Adele Laurie Dennis

    During the early stages of star formation, an embedded protostar accretes mass and simultaneously expels mass and angular momentum in the form of a bipolar outflow. In the common case of clustered star formation, outflows likely impact their surrounding environment and influence subsequent star formation. Numerical simulations have shown that outflows can sustain turbulence and maintain a cluster in quasi-equilibrium; alternatively, it was proposed that outflows may trigger rather than regulate or inhibit star formation. Observations of outflows and their impact on clusters are challenging because they must probe spatial scales over several orders of magnitude --- from the size of a core (a few hundred AU, or N ~ 10-3 pc) to a cluster (a few pc) --- and previous works generally focused on one scale or the other. This thesis incorporates high-resolution, high-sensitivity interferometry observations (with millimeter/sub-millimeter wavelengths) complemented by observations obtained using single dish telescopes in order to assess molecular outflow properties and their cumulative impact in two young protostellar clusters: Serpens South and NGC 1333. Based on these case studies, I develop an evolutionary scenario for clustered star formation spanning the ages of the two clusters, about 0.1 - 1 Myr. Within this scenario, outflows in both Serpens South and NGC 1333 provide sufficient energy to sustain turbulence early in the protocluster formation process. In neither cluster do outflows provide enough energy to counter the gravitational potential energy and disrupt the entire cluster. However, most of the mass in outflows in both clusters have velocities greater than the escape velocity, and therefore the relative importance of outflow-driven turbulence compared with gravitational potential likely changes with time as ambient gas escapes. We estimate that enough gas mass will escape via outflows in Serpens South so that it will come to resemble NGC 1333 in terms of its

  20. The SCUBA-2 Cosmology Legacy Survey: Multi-wavelength Properties of ALMA-identified Submillimeter Galaxies in UKIDSS UDS

    NASA Astrophysics Data System (ADS)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Ivison, R. J.; Dunlop, J. S.; Geach, J. E.; Almaini, O.; Arumugam, V.; Bremer, M. N.; Chen, Chian-Chou; Conselice, C.; Coppin, K. E. K.; Farrah, D.; Ibar, E.; Hartley, W. G.; Ma, C. J.; Michałowski, M. J.; Scott, D.; Spaans, M.; Thomson, A. P.; van der Werf, P. P.

    2017-04-01

    We present a multi-wavelength analysis of 52 submillimeter galaxies (SMGs), identified using ALMA 870 μm continuum imaging in a pilot program to precisely locate bright SCUBA-2-selected submillimeter sources in the UKIDSS Ultra Deep Survey (UDS) field. Using the available deep (especially near-infrared) panoramic imaging of the UDS field at optical-to-radio wavelengths we characterize key properties of the SMG population. The median photometric redshift of the bright ALMA/SCUBA-2 UDS (AS2UDS) SMGs that are detected in a sufficient number of wavebands to derive a robust photometric redshift is z = 2.65 ± 0.13. However, similar to previous studies, 27% of the SMGs are too faint at optical-to-near-infrared wavelengths to derive a reliable photometric redshift. Assuming that these SMGs lie at z ≳ 3 raises the median redshift of the full sample to z = 2.9 ± 0.2. A subset of 23 unlensed, bright AS2UDS SMGs have sizes measured from resolved imaging of their rest-frame far-infrared emission. We show that the extent and luminosity of the far-infrared emission are consistent with the dust emission arising from regions that are, on average, optically thick at a wavelength of {λ }0≥slant 75 μ {{m}} (1σ dispersion of 55-90 μm). Using the dust masses derived from our optically thick spectral energy distribution models, we determine that these galaxies have a median hydrogen column density of N H = 9.8{}-0.7+1.4 × 1023 cm-2, or a corresponding median V-band obscuration of A v = 540{}-40+80 mag, averaged along the line of sight to the source of their rest-frame ˜200 μm emission. We discuss the implications of this extreme attenuation by dust for the multi-wavelength study of dusty starbursts and reddening-sensitive tracers of star formation.

  1. Neptune’s global circulation deduced from multi-wavelength observations

    NASA Astrophysics Data System (ADS)

    de Pater, Imke; Fletcher, Leigh N.; Luszcz-Cook, Statia; DeBoer, David; Butler, Bryan; Hammel, Heidi B.; Sitko, Michael L.; Orton, Glenn; Marcus, Philip S.

    2014-07-01

    We observed Neptune between June and October 2003 at near- and mid-infrared wavelengths with the 10-m W.M. Keck II and I telescopes, respectively; and at radio wavelengths with the Very Large Array. Images were obtained at near-infrared wavelengths with NIRC2 coupled to the adaptive optics system in both broad- and narrow-band filters between 1.2 and 2.2 μm. In the mid-infrared we imaged Neptune at wavelengths between 8 and 22 μm, and obtained slit-resolved spectra at 8-13 μm and 18-22 μm. At radio wavelengths we mapped the planet in discrete filters between 0.7 and 6 cm. We analyzed each dataset separately with a radiative-transfer program that is optimized for that particular wavelength regime. At southern midlatitudes the atmosphere appears to be cooler at mid-infrared wavelengths than anywhere else on the planet. We interpret this to be caused by adiabatic cooling due to air rising at midlatitudes at all longitudes from the upper troposphere up to ≲0.1 mbar levels. At near-infrared wavelengths we find two distinct cloud layers at these latitudes: a relatively deep layer of clouds (presumably methane) in the troposphere at pressure levels P∼300-≳600 mbar, which we suggest to be caused by the large-scale upwelling and its accompanying adiabatic cooling and condensation of methane; and a higher, spatially intermittent, layer of clouds in the stratosphere at 20-30 mbar. The latitudes of these high clouds encompass an anticyclonic band of zonal flow, which suggests that they may be due to strong, but localized, vertical upwellings associated with local anticyclones, rather than plumes in convective (i.e., cyclonic) storms. Clouds at northern midlatitudes are located at the highest altitudes in the atmosphere, near 10 mbar. Neptune’s south pole is considerably enhanced in brightness at both mid-infrared and radio wavelengths, i.e., from ∼0.1 mbar levels in the stratosphere down to tens of bars in the troposphere. We interpret this to be due to subsiding

  2. Multi-wavelength Yb:YAG/Nd3+:YVO4 continuous-wave microchip Raman laser.

    PubMed

    Wang, Xiao-Lei; Dong, Jun; Wang, Xiao-Jie; Xu, Jie; Ueda, Ken-Ichi; Kaminskii, Alexander A

    2016-08-01

    Multi-wavelength continuous-wave (CW) Raman lasers in a laser diode pumped Yb:YAG/Nd3+:YVO4 microchip Raman laser have been demonstrated for the first time to our best knowledge. The multi-wavelength laser of the first Stokes radiation around 1.08 μm has been achieved with a Raman shift of 261  cm-1 for a-cut Nd:YVO4 crystal corresponding to the fundamental wavelength at 1.05 μm. Multi-wavelength laser operation simultaneously around 1.05 and 1.08 μm has been achieved under the incident pump power between 1.5 and 1.7 W. Multi-wavelength Raman laser with frequency separation of 1 THz around 1.08 μm has been obtained when the incident pump power is higher than 1.7 W. The maximum Raman laser output power of 260 mW at 1.08 μm is obtained and the corresponding optical-to-optical conversion efficiency is 4.2%. Elliptically polarized fundamental laser and linearly polarized Raman laser were observed in an Yb:YAG/Nd:YVO4 CW microchip Raman laser. The experimental results of linearly polarized, multi-wavelength Yb:YAG/Nd:YVO4 CW microchip Raman laser with adjustable frequency separation provide a novel approach for developing potential compact laser sources for Terahertz generation.

  3. Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during the 2015 outburst

    DOE PAGES

    Chandra, Sunil; Zhang, Haocheng; Kushwaha, Pankaj; ...

    2015-08-17

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energymore » distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. Furthermore, the rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.« less

  4. Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during the 2015 outburst

    SciTech Connect

    Chandra, Sunil; Zhang, Haocheng; Kushwaha, Pankaj; Singh, K. P.; Bottcher, M.; Kaur, Navpreet; Baliyan, K. S.

    2015-08-17

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energy distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. Furthermore, the rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.

  5. PKS 2155-304 in July 2006: H.E.S.S. results and simultaneous multi-wavelength observations

    SciTech Connect

    Lenain, Jean-Philippe; Boisson, Catherine; Sol, Helne; Zech, Andreas; Benbow, Wystan; Buehler, Rolf; Costamante, Luigi; Raue, Martin; Giebels, Berrie; Superina, Giulia; Punch, Michael; Volpe, Francesca

    2008-12-24

    The high-frequency-peaked BL Lac PKS 2155-304 is one of the brightest and best-studied VHE {gamma}-ray sources in the southern hemisphere. The High Energy Stereoscopic System (H.E.S.S.) has monitored PKS 2155-304 in 2006 and a multi-wavelength campaign involving X-ray, optical and radio observatories was triggered by the detection of an active state in July 2006, followed by the detection of two extraordinary flares on July, 28th and 30th, with peak fluxes {approx}100 times the usual values. We present results from the spectral and flux variability analysis of the VHE and simultaneous X-ray observations with Chandra during the second flare, as well as the detailed evolution of the VHE flux of PKS 2155-304 observed by H.E.S.S. in 2006. A study of flux correlations in the different frequency ranges during the second flare and the adjacent nights is discussed. We also present an interpretation of the active state of PKS 2155-304 in the framework of synchrotron self-Compton emission.

  6. Assessment of multi-wavelength pulse photometry for non-invasive dose estimation of circulating drugs and nanoparticles

    NASA Astrophysics Data System (ADS)

    Adhikari, Pratik; Eklund, Wakako; Sherer, Eric A.; O'Neal, D. Patrick

    2016-03-01

    The feasibility of multi-wavelength photoplethysmography for the real-time sensing of absorptive and scattering agents in pulsatile blood is discussed. The use of pulsatile signals extracted from trans-illumination of an accessible section of tissue allows us to calculate the concentration of the optically extinctive species in the pulsatile blood. This technology, initially used for pulse oximetry and dye densitometry, can be applied to monitor in vivo concentration and clearance of various absorptive species. Recently, our prototype has been used monitor the concentration of therapeutic gold nanoparticles, antimalarial quinine, and the antifungal agent amphotericin B. The assessment of the optical properties, device specifications, and signal quality for each compound are presented. We observe that this technology can be used to monitor numerous extinctive drug and nano-materials that present features in the 350-1100 nm range. The rationale for using this technology in a clinical setting would be to improve outcomes by real-time pharmacological feedback and/or control at point of care in addition to the elimination of invasive blood draws for collection of data.

  7. Diode-pumped simultaneous multi-wavelength linearly polarized Nd:YVO4 laser at 1062, 1064 and 1066 nm

    NASA Astrophysics Data System (ADS)

    Lin, Zhi; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping

    2016-01-01

    We report on a diode-end-pumped simultaneous multiple wavelength Nd:YVO4 laser. Dual-wavelength laser is achieved at a π-polarized 1064 nm emission line and a σ-polarized 1066 nm emission line with total maximum output power of 1.38 W. Moreover, tri-wavelength laser emission at the π-polarized 1064 nm emission line and σ-polarized 1062 and 1066 nm emission lines can also be obtained with total maximum output power of about 1.23 W, for the first time to our knowledge. The operation of such simultaneous dual- and tri-wavelength lasers is only realized by employing a simple glass etalon to modulate the intracavity losses for these potential lasing wavelengths inside of an intracavity polarizer, which therefore makes a very compact two-mirror linear cavity and simultaneous orthogonal lasing possible. Such orthogonal linearly polarized multi-wavelength laser sources could be especially promising in THz wave generation and in efficient nonlinear frequency conversion to visible lasers.

  8. Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state

    DOE PAGES

    Ackermann, M.; Ajello, M.; Ballet, J.; ...

    2012-05-17

    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February.Here, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazarmore » emission models. We also find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. Finally, we model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.« less

  9. Multi-wavelength photometry of the T Tauri binary V582 Mon (KH 15D): A new epoch of occultations

    SciTech Connect

    Windemuth, Diana; Herbst, William

    2014-01-01

    We present multi-wavelength (VRIJHK) observations of KH 15D obtained in 2012/2013, as well as a master table of standard photometry spanning the years 1967 to 2013. The system is a close, eccentric T Tauri binary embedded in an inclined precessing circumbinary (CB) ring. The most recent data show the continued rise of star B with respect to the trailing edge of the occulting horizon as the system's maximum brightness steadily increases. The wealth of data in time and wavelength domains allows us to track the long-term CCD color evolution of KH 15D. We find that the V – I behavior is consistent with direct and scattered light from the composite color of two stars with slightly different temperatures. There is no evidence for any reddening or bluing associated with extinction or scattering by interstellar-medium-size dust grains. Furthermore, we probe the system's faint phase behavior at near-infrared wavelengths in order to investigate extinction properties of the ring and signatures of a possible shepherding planet sometimes invoked to confine the CB ring at ∼5 AU. The wavelength independence of eclipse depth at second contact is consistent with the ring material being fully opaque to 2.2 μm. The color-magnitude diagrams demonstrate excess flux in J and H at low light levels, which may be due to the presence of a hot, young Jupiter-mass planet.

  10. A Multi-wavelength Look At Dust Evolution At z 0.16, 0.24 And 0.32

    NASA Astrophysics Data System (ADS)

    Moore, Carolynn A.; Dale, D. A.; Barlow, R. J.; Cohen, S. A.; Cook, D.; Johnson, L. C.; Kattner, S. M.; Schuster, M. D.; Staudaher, S.; Thatcher, J. W.

    2009-01-01

    We report results from the Wyoming Survey for Hα (WySH), a comprehensive four-square degree survey to probe the evolution of star-forming galaxies over the latter half of the age of the Universe. We have supplemented the Hα data from WySH with infrared data from the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE) and ultraviolet data from the Galaxy Evolution Explorer (GALEX) Deep Imaging Survey. This dataset provides a multi-wavelength look at the evolution of dust extinction, and here we compare a traditional measure of dust extinction (TIR/FUV) to a more recent diagnostic, [L(Hα) + 0.031L(24μm)]/L(Hα), which is based on a new robust star formation rate (SFR) indicator, SFR[Hα+24μm]. With such data over multiple epochs, the evolution in dust extinction with redshift can be assessed. We present preliminary results from the ELAIS-N1 and Lockman Hole regions at z 0.16, 0.24, and 0.32. This research has been funded by the National Science Foundation and the Wyoming Space Grant Consortium.

  11. Switchable and multi-wavelength linear fiber laser based on Fabry-Perot and Mach-Zehnder interferometers

    NASA Astrophysics Data System (ADS)

    Gutierrez-Gutierrez, J.; Rojas-Laguna, R.; Estudillo-Ayala, J. M.; Sierra-Hernández, J. M.; Jauregui-Vazquez, D.; Vargas-Treviño, M.; Tepech-Carrillo, L.; Grajales-Coutiño, R.

    2016-09-01

    In this manuscript, switchable and multi-wavelength erbium-doped fiber laser arrangement, based on Fabry-Perot (FPI) and Mach-Zehnder (MZI) interferometers is presented. Here, the FPI is composed by two air-microcavities set into the tip of conventional single mode fiber, this one is used as a partially reflecting mirror and lasing modes generator. And the MZI fabricated by splicing a segment of photonic crystal fiber (PCF) between a single-mode fiber section, was set into an optical fiber loop mirror that acts as full-reflecting and wavelength selective filter. Both interferometers, promotes a cavity oscillation into the fiber laser configuration, besides by curvature applied over the MZI, the fiber laser generates: single, double, triple and quadruple laser emissions with a signal to noise ratio (SNR) of 30 dB. These laser emissions can be switching between them from 1525 nm to 1534 nm by adjusting the curvature radius over the MZI. This laser fiber offers a wavelength and power stability at room temperature, compactness and low implementation cost. Moreover the linear laser proposed can be used in several fields such as spectroscopy, telecommunications and fiber optic sensing systems.

  12. Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

    NASA Astrophysics Data System (ADS)

    Saturno, Jorge; Pöhlker, Christopher; Massabò, Dario; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditas, Florian; Hrabě de Angelis, Isabella; Morán-Zuloaga, Daniel; Pöhlker, Mira L.; Rizzo, Luciana V.; Walter, David; Wang, Qiaoqiao; Artaxo, Paulo; Prati, Paolo; Andreae, Meinrat O.

    2017-08-01

    Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP) data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA), which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June-September 2014). The mean absorption coefficient (at 637 nm) during this period was 1.8 ± 2.1 Mm-1, with a maximum of 15.9 Mm-1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS) retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

  13. Tunable and switchable Brillouin multi-wavelength thulium fluoride fiber laser in S/S+ band region

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Ooi, S. I.; Samion, M. Z.; Jasim, A. A.; Tiu, Z. C.

    2017-08-01

    In this work, a multi-wavelength fiber laser with a channel spacing of 0.17 nm operating in the S-band region is proposed and demonstrated. The proposed laser exploits the stimulated Brillouin scattering (SBS) effect to generate the desired output using a 6.9 km long dispersion shifted fiber. A Thulium-Fluoride fiber (TFF) pumped at 1400 nm enables gain and operation in the S-band region. With a Brillouin pump (BP) wavelength of 1503.6 nm and power of 12 dBm, up to 3 well defined even Stokes lines are obtained at the maximum pump power of 250 mW. Furthermore, more even Stokes lines and anti-Stokes lines are also observed at the afore-mentioned setting, although they are less well defined as the first 3 even Stokes. The laser has an operating range of 1470-1515 nm, with tunability enabled by changing the BP wavelength. Furthermore, the spacing between the lasing wavelengths can be switched from 0.17 nm to 0.08 nm by adjusting the integrated air gap in the laser cavity, making the proposed laser highly suitable for applications such as communications and sensing. This is, the first time to the author's knowledge that such a system has been demonstrated.

  14. Central-wavelength-tunable multi-wavelength fiber laser based on micro-air gap cavity and tapered fiber structure

    NASA Astrophysics Data System (ADS)

    Chen, Jiao; Tong, Zhengrong; Yang, He; Zhang, Weihua; Xue, Lifang; Pan, Honggang

    2017-08-01

    A multi-wavelength erbium-doped fiber laser based on a micro-air gap cavity filter and the tapered fiber structure is proposed and demonstrated. The micro-air gap cavity filter is constructed by aligning two polished single mode fiber facets carefully through a capillary. Then a tapered fiber structure is applied to compose a cascaded filter with the micro-air gap cavity filter. According to the experiment, the transmission spectrum of the tapered fiber structure acts as the outer envelope of the cascaded structure, which is used as a tunable filter. Moreover, the periodically localized peaks of the tapered fiber structure are modulated by sinusoidal spectral response of the micro-air gap cavity filter. And the micro-air gap cavity filter acts as a comb filter, which determines the channel space of the cascaded filter structure. By using the above superimposed filter, four wavelengths with a wavelength spacing of about 1.20 nm are generated under the pump power of 270 mW. The side-mode suppression ratio of all lasing wavelengths is about 35 dB. The tapered fiber structure is fixed on a furnace, when the temperature varies from 30 °C to 120 °C, the first wavelength can be tuned within the range of 5.31 nm.

  15. Brown carbon and thermal-optical analysis: A correction based on optical multi-wavelength apportionment of atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Massabò, D.; Caponi, L.; Bove, M. C.; Prati, P.

    2016-01-01

    Thermo-optical analysis is widely adopted for the quantitative determination of total, TC, organic, OC and elemental, EC, Carbon in aerosol samples collected on quartz fibre filters. Nevertheless, the methodology presents several issues in particular about the artefacts related to the formation of pyrolytic carbon. It is usually neglected the uncertainty due to the possible presence of brown carbon (BrC) in the sample under analysis, i.e. the optically active fraction of OC produced by biomass burning and with characteristics intermediate between OC and EC. We introduce here a novel correction to the standard thermo-optical protocol based on the determination of the fraction of the sample absorbance due to the (possible) presence of BrC. This is achievable thanks to the coupled use of the Multi Wavelength Absorbance Analyser (MWAA) of the University of Genoa and a standard Sunset Inc. EC/OC analyser. Our correction provides a firmer OC/EC separation as well as an operative quantification of the BrC mass. The methodology has been validated against independent determination of the levoglucosan content in the same filters sent to the Sunset analysis. Corrections up to 23% in the OC and EC values, determined via the standard and new thermo-optical analysis, have been found in a set of PM10 (i.e. Particulate Matter with aerodynamic diameter less than 10 μm) samples collected wintertime at a mountain site in Northern Italy.

  16. Multi-wavelength emissions from the millisecond pulsar binary PSR J1023+0038 during an accretion active state

    SciTech Connect

    Takata, J.; Leung, Gene C. K.; Wu, E. M. H.; Cheng, K. S.; Li, K. L.; Kong, A. K. H.; Tam, P. H. T.; Hui, C. Y.; Xing, Yi; Wang, Zhongxiang; Cao, Yi; Tang, Sumin E-mail: akong@phys.nthu.edu.tw

    2014-04-20

    Recent observations strongly suggest that the millisecond pulsar binary PSR J1023+0038 has developed an accretion disk since 2013 June. We present a multi-wavelength analysis of PSR J1023+0038, which reveals that (1) its gamma-rays suddenly brightened within a few days in 2013 June/July and has remained at a high gamma-ray state for several months; (2) both UV and X-ray fluxes have increased by roughly an order of magnitude; and (3) the spectral energy distribution has changed significantly after the gamma-ray sudden flux change. Time variabilities associated with UV and X-rays are on the order of 100-500 s and 50-100 s, respectively. Our model suggests that a newly formed accretion disk, due to the sudden increase of the stellar wind, could explain the changes of all these observed features. The increase of UV is emitted from the disk, and a new component in gamma-rays is produced by inverse Compton scattering between the new UV component and pulsar wind. The increase of X-rays results from the enhancement of injection pulsar wind energy into the intra-binary shock due to the increase of the stellar wind. We also predict that the radio pulses may be blocked by the evaporated winds from the disk, and the pulsar is still powered by rotation.

  17. MULTI-WAVELENGTH STUDY OF FLARING ACTIVITY IN BL Lac OBJECT S5 0716+714 DURING THE 2015 OUTBURST

    SciTech Connect

    Chandra, Sunil; Kushwaha, Pankaj; Singh, K. P.; Zhang, Haocheng; Bottcher, M.; Kaur, Navpreet; Baliyan, K. S.

    2015-08-20

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of 2015 January. Observed almost simultaneously in the optical, X-rays, and γ-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A TeV (VHE) detection was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about five days apart, were seen in almost all of the energy bands. The multi-wavelength light curves, spectral energy distribution, and polarization are modeled using the time-dependent code developed by Zhang et al. This model assumes a straight jet threaded by large-scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. The rapid variation in PD and rotation in PA are most likely due to reconnections happening in the emission region in the jet, as suggested by the change in the ratio of toroidal to poloidal components of the magnetic field during the quiescent and flaring states.

  18. Overview of North Ecliptic Pole Deep Multi-wavelength Survey as a Probe of the Cosmic Noon Era

    NASA Astrophysics Data System (ADS)

    Matsuhara, Hideo; Oi, Nagisa

    2015-08-01

    An overview of the North Ecliptic Pole deep (0.5 deg2, NEP-Deep) multi-wavelength survey covering from X-ray to radio-wave is presented. The NEP-Deep provides us with several thousands of 15 μm or 18 μm selected sample of galaxies, which is the largest sample ever made at these wavelengths. A continuous filter coverage in the mid-infrared wavelength (7, 9, 11, 15, 18, and 24 μm) is unique and vital to diagnose the contributions from starbursts and AGNs in the galaxies out to z=2. The goal of the project is to resolve the nature of the cosmic star formation history at the cosmic noon era (e.g. z=1--2), and to find a clue to understand its decline from z=1 to present universe by utilizing the unique power of the multiwavelength survey. To achieve the goal we use a few diagnostic physical parameters unique to the NEP dataset: specific star-formation rate, dust attenuation, and obscured AGN fraction, etc.It is also noteworthy that the NEP is the legacy field thanks to its high visibility by the space observatories, such as eROSITA, Euclid, JWST, and SPICA. SPICA, the next generation large cooled space telescope is extremely powerful to study the rise and fall of the cosmic star-formation history in the universe.

  19. Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state

    SciTech Connect

    Ackermann, M.; Ajello, M.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cutini, S.; D'Ammando, F.; de Palma, F.; Dermer, C. D.; do Couto e Silva, E.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Fuhrmann, L.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hughes, R. E.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Lee, S. -H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Nishino, S.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Pelassa, V.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Rastawicki, D.; Razzano, M.; Readhead, A.; Reimer, A.; Reimer, O.; Reyes, L. C.; Richards, J. L.; Sbarra, C.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Szostek, A.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.; Moderski, R.; Nalewajko, K.; Sikora, M.; Villata, M.; Raiteri, C. M.; Aller, H. D.; Aller, M. F.; Arkharov, A. A.; Benítez, E.; Berdyugin, A.; Blinov, D. A.; Boettcher, M.; Bravo Calle, O. J. A.; Buemi, C. S.; Carosati, D.; Chen, W. P.; Diltz, C.; Di Paola, A.; Dolci, M.; Efimova, N. V.; Forné, E.; Gurwell, M. A.; Heidt, J.; Hiriart, D.; Jordan, B.; Kimeridze, G.; Konstantinova, T. S.; Kopatskaya, E. N.; Koptelova, E.; Kurtanidze, O. M.; Lähteenmäki, A.; Larionova, E. G.; Larionova, L. V.; Larionov, V. M.; Leto, P.; Lindfors, E.; Lin, H. C.; Morozova, D. A.; Nikolashvili, M. G.; Nilsson, K.; Oksman, M.; Roustazadeh, P.; Sievers, A.; Sigua, L. A.; Sillanpää, A.; Takahashi, T.; Takalo, L. O.; Tornikoski, M.; Trigilio, C.; Troitsky, I. S.; Umana, G.; Angelakis, E.; Krichbaum, T. P.; Nestoras, I.; Riquelme, D.; Krips, M.; Trippe, S.; Arai, A.; Kawabata, K. S.; Sakimoto, K.; Sasada, M.; Sato, S.; Uemura, M.; Yamanaka, M.; Yoshida, M.; Belloni, T.; Tagliaferri, G.; Bonning, E. W.; Isler, J.; Urry, C. M.; Hoversten, E.; Falcone, A.; Pagani, C.; Stroh, M.

    2012-05-17

    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February.Here, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We also find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. Finally, we model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.

  20. Tunable multi-wavelength thulium-doped fiber laser incorporating two-stage cascaded Sagnac loop comb filter

    NASA Astrophysics Data System (ADS)

    Zhu, Lianqing; He, Wei; Dong, Mingli; Lou, Xiaoping; Luo, Fei

    2016-08-01

    A tunable multi-wavelength narrow-linewidth thulium-doped fiber laser employing two-stage cascaded Sagnac loop mirrors is proposed and experimentally demonstrated. The designed fiber laser is composed of a pump source, wavelength division multiplex, circulator, thulium-doped fiber, polarization controllers (PCs), couplers and polarization-maintaining fibers (PMFs). Two cascaded Sagnac loops are used as the cavity reflector and filter, and the proposed filter is fabricated using two sections of PMFs with 2-m and 1-m lengths, respectively. In the experiment, the laser threshold is 110 mW, and laser can emit single, double, triple, quadruple and quintuple wavelengths in the spectral range of 1873-1901 nm through the simultaneous adjustment of the two PCs. The power fluctuations and 3-dB linewidth are less than 2.1 dB and 0.2 nm, respectively, over 10 min at room temperature, and the side-mode suppression ratio is greater than 20 dB. The proposed laser will be useful in various fields, such as spectral analysis, fiber sensing and optical communication.

  1. Real-time imaging for cerebral ischemia in rats using the multi-wavelength handheld photoacoustic system

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Hang; Xu, Yu; Chan, Kim Chuan; Mehta, Kalpesh; Thakor, Nitish; Liao, Lun-De

    2017-02-01

    Stroke is the second leading cause of death worldwide. Rapid and precise diagnosis is essential to expedite clinical decision and improve functional outcomes in stroke patients; therefore, real-time imaging plays an important role to provide crucial information for post-stroke recovery analysis. In this study, based on the multi-wavelength laser and 18.5 MHz array-based ultrasound platform, a real-time handheld photoacoustic (PA) system was developed to evaluate cerebrovascular functions pre- and post-stroke in rats. Using this system, hemodynamic information such as cerebral blood volume (CBV) can be acquired for assessment. One rat stroke model (i.e., photothrombotic ischemia (PTI)) was employed for evaluating the effect of local ischemia. For achieving better intrinsic PA contrast, Vantage and COMSOL simulations were applied to optimize the light delivery (e.g., interval between two arms) from customized fiber bundle, while phantom experiment was conducted to evaluate the imaging performance of this system. Results of phantom experiment showed that hairs ( 150 μm diameter) and pencil lead (500 μm diameter) can be imaged clearly. On the other hand, results of in vivo experiments also demonstrated that stroke symptoms can be observed in PTI model poststroke. In the near future, with the help of PA specific contrast agent, the system would be able to achieve blood-brain barrier leakage imaging post-stroke. Overall, the real-time handheld PA system holds great potential in disease models involving impairments in cerebrovascular functions.

  2. Multi-wavelength generation using a bismuth-based EDF and Brillouin effect in a linear cavity configuration

    NASA Astrophysics Data System (ADS)

    Shahi, S.; Harun, S. W.; Shahabuddin, N. S.; Shirazi, M. R.; Ahmad, H.

    2009-03-01

    The generation of a multiple wavelength source using a bismuth-based erbium-doped fiber (Bi-EDF) in a linear cavity configuration is demonstrated. The configuration uses a pair of optical circulators at the input and output ends of the cavity to form a resonator for multi-wavelength generation in conjunction with optical couplers to inject the Brillouin pump (BP) and to tap the output at the two ends. The Brillouin erbium fiber laser (BEFL) comb with a 2.15 m of Bi-EDF has a wavelength spacing of 0.09 nm and operates in long-wavelength (L-) band region. A stable output laser comb of 50 lines is obtained at a BP of 1568.2 nm and 5 dBm and two 1480 nm pumps at 120 mW. The injected BP wavelength and power as well as the 1480 nm pump powers have a great effect on the number of lines and output power of the BEFL. This configuration is compact due to the use of the significantly shorter Bi-EDF as the linear gain medium, and can be made more compact by replacing the single-mode fiber with highly non-linear fibers such as holey fibers.

  3. Multi-wavelength Observations of Blazar AO 0235+164 in the 2008-2009 Flaring State

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cutini, S.; D'Ammando, F.; de Palma, F.; Dermer, C. D.; Silva, E. do Couto e.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Fuhrmann, L.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hughes, R. E.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Lee, S.-H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Nishino, S.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Pelassa, V.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Rastawicki, D.; Razzano, M.; Readhead, A.; Reimer, A.; Reimer, O.; Reyes, L. C.; Richards, J. L.; Sbarra, C.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Szostek, A.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.; Fermi-LAT Collaboration; Moderski, R.; Nalewajko, K.; Sikora, M.; Villata, M.; Raiteri, C. M.; Aller, H. D.; Aller, M. F.; Arkharov, A. A.; Benítez, E.; Berdyugin, A.; Blinov, D. A.; Boettcher, M.; Bravo Calle, O. J. A.; Buemi, C. S.; Carosati, D.; Chen, W. P.; Diltz, C.; Di Paola, A.; Dolci, M.; Efimova, N. V.; Forné, E.; Gurwell, M. A.; Heidt, J.; Hiriart, D.; Jordan, B.; Kimeridze, G.; Konstantinova, T. S.; Kopatskaya, E. N.; Koptelova, E.; Kurtanidze, O. M.; Lähteenmäki, A.; Larionova, E. G.; Larionova, L. V.; Larionov, V. M.; Leto, P.; Lindfors, E.; Lin, H. C.; Morozova, D. A.; Nikolashvili, M. G.; Nilsson, K.; Oksman, M.; Roustazadeh, P.; Sievers, A.; Sigua, L. A.; Sillanpää, A.; Takahashi, T.; Takalo, L. O.; Tornikoski, M.; Trigilio, C.; Troitsky, I. S.; Umana, G.; GASP-WEBT Consortium; Angelakis, E.; Krichbaum, T. P.; Nestoras, I.; Riquelme, D.; F-GAMMA; Krips, M.; Trippe, S.; Iram-PdBI; Arai, A.; Kawabata, K. S.; Sakimoto, K.; Sasada, M.; Sato, S.; Uemura, M.; Yamanaka, M.; Yoshida, M.; Kanata; Belloni, T.; Tagliaferri, G.; RXTE; Bonning, E. W.; Isler, J.; Urry, C. M.; SMARTS; Hoversten, E.; Falcone, A.; Pagani, C.; Stroh, M.; (Swift-XRT

    2012-06-01

    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.

  4. A Multi-Wavelength Study of the Gamma-Ray Binary 1FGL J1018.6-5856

    NASA Astrophysics Data System (ADS)

    Coley, Joel Barry; Corbet, Robin; Cheung, Chi C.; Dubus, Guillaume; Edwards, Philip; McBride, Vanessa; Stevens, Jamie

    2016-04-01

    1FGL J1018.6-5856, the first gamma-ray binary discovered by the Fermi Large Area Telescope (LAT), consists of an O6 V((f)) star and suspected rapidly spinning pulsar. While 1FGL J1018.6-5856 has been postulated to be powered by the interaction between a relativistic pulsar wind and the stellar wind of the companion, a microquasar scenario where the compact object is a black hole cannot be ruled out. We present the first extensive multi-wavelength analysis of 1FGL J1018.6-5856 with the Australia Telescope Compact Array (ATCA), Fermi LAT and the Swift X-ray Telescope (XRT) to better determine the properties of the 16.531$\\pm$0.006 day orbital modulation. The radio amplitude modulation is found to decline with increasing frequency, which is a possible indication of the presence of free-free absorption. This is further supported by the absence of clear modulation in the 33.0 and 35.0\\,GHz bands, which were not previously reported. The best-fit spectral model of the Swift XRT data consists of a featureless power law with index $\\Gamma\\sim$1.3--1.7 modified by an absorber that fully covers the source. This is possible evidence that 1FGL J1018.6-5856 is a non-accreting system.

  5. Multi-wavelength sensitive holographic polymer dispersed liquid crystal grating applied within image splitter for autostereoscopic display

    NASA Astrophysics Data System (ADS)

    Zheng, Jihong; Wang, Kangni; Gao, Hui; Lu, Feiyue; Sun, Lijia; Zhuang, Songlin

    2016-09-01

    Multi-wavelength sensitive holographic polymer dispersed liquid crystal (H-PDLC) grating and its application within image splitter for autostereoscopic display are reported in this paper. Two initiator systems consisting of photoinitiator, Methylene Blue and coinitiator, p-toluenesulfonic acid as well as photoinitiator, Rose Bengal and coinitiator, Nphenylglycine are employed. We demonstrate that Bragg gratings can be formed in this syrup polymerized under three lasers simultaneously including 632.8nm from He-Ne laser, 532nm from Verdi solid state laser, and 441.6nm from He- Cd laser. The diffraction efficiency of three kinds of gratings with different exposure wavelength are 57%, 75% and 33%, respectively. The threshold driving voltages of those gratings are 2.8, 3.05, and 2.85 V/μm, respectively. We also present the results for the feasibility of this proposed H-PDLC grating applied into image splitter without color dispersion for autostereoscopic display according to experimental splitting effect.

  6. Quantitative photoacoustic blood oxygenation measurement of whole porcine blood samples using a multi-wavelength semiconductor laser system

    NASA Astrophysics Data System (ADS)

    Friedrich, Claus-Stefan; Mienkina, Martin P.; Brenner, Carsten; Gerhardt, Nils C.; Jörger, Manfred; Strauß, Andreas; Beckmann, Martin F.; Schmitz, Georg; Hofmann, Martin R.

    2011-07-01

    We present a photoacoustic measurement system based on semiconductor lasers for blood oxygenation measurements. It permits to use four different optical wavelengths (650nm, 808nm, 850nm, 905nm) to generate photoacoustic signals. As the optical extinction coefficient of oxygenated hemoglobin and deoxygenated hemoglobin is different at specific wavelengths, a blood oxygenation measurement by a multi-wavelength photoacoustic laser system is feasible. Especially at 650nm, the clear difference between the extinction coefficients of the two hemoglobin derivates permits to determine the blood oxygenation in combination with other near infrared wavelengths. A linear model based on tabulated values of extinction coefficients for fully oxygenated and fully deoxygenated hemoglobin is presented. We used heparin stabilized whole porcine blood samples to model the optical behavior of human blood, as the optical absorption behavior of porcine hemoglobin does not differ significantly from human hemoglobin. To determine the real oxygen saturation values of the blood samples, we measured the partial oxygen pressure with an IRMA Trupoint Blood Analysis System. The oxygen saturation values were calculated from a dissociation curve for porcine blood. The results of the photoacoustic measurement are in qualitatively good agreement with the predicted linear model. Further, we analyze the abilities and the limitations of quantitative oxygenation measurements.

  7. Comparisons of multi-wavelength oscillations using Sagnac loop mirror and Mach-Zehnder interferometer for ytterbium doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Moghaddam, M. R. A.; Harun, S. W.; Shahi, S.; Lim, K. S.; Ahmad, H.

    2010-02-01

    A multiwavelength Ytterbium-doped fiber ring laser operating at 1030 nm region is demonstrated using a Sagnac loop mirror and a Mach-Zehnder interferometer. We report the Performance comparisons of multi-wavelength oscillations in Yb3+ doped fiber lasers (YDFL) with typical commercial ytterbium doped silica fibers. By adjusting the polarization controller (PC), a widely tunable laser range of 22 nm from 1030 nm to 1050 nm is obtained. The Mach-Zehnder interferometer (MZI) design has exhibited simplicity in the operation for controlling the smallest wavelength spacing compared to Sagnac loop mirror method. In our observations, the smallest achieved stable wavelength spacing in Sagnac loop mirror setup and MZI setup were 2.1 nm and 0.7 nm, respectively. In case of nine-wavelength operation with a MZI setup, the stability, Full Width at Half Maximum (FWHM) and side mode suppression ratio (SMSR) of laser lines are not affected by increasing pump power, While for above four wavelength operation, the laser stability with Sagnac loop mirror becomes worse specially for higher input pump power and the power fluctuation among the wave-lengths would be also slightly larger.

  8. Multi-wavelength Study of the Supernova Remnant Kes 79 (G33.6+0.1): On Its Supernova Properties and Expansion into a Molecular Environment

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Chen, Yang; Safi-Harb, Samar; Zhou, Xin; Sun, Ming; Zhang, Zhi-Yu; Zhang, Gao-Yuan

    2016-11-01

    Kes 79 (G33.6+0.1) is an aspherical thermal composite supernova remnant (SNR) observed across the electromagnetic spectrum and showing an unusual highly structured morphology, in addition to harboring a central compact object (CCO). Using the CO J = 1-0, J = 2-1, and J = 3-2 data, we provide the first direct evidence and new morphological evidence to support the physical interaction between the SNR and the molecular cloud in the local standard of rest velocity ˜ 105 {km} {{{s}}}-1. We revisit the 380 ks XMM-Newton observations and perform a dedicated spatially resolved X-ray spectroscopic study with careful background subtraction. The overall X-ray-emitting gas is characterized by an under-ionized ({τ }{{c}}˜ 6× {10}11 {{cm}}-3) cool ({{kT}}{{c}}≈ 0.20 keV) plasma with solar abundances, plus an under-ionized ({τ }{{h}}˜ 8× {10}10 {{cm}}-3) hot ({{kT}}{{h}}≈ 0.80 keV) plasma with elevated Ne, Mg, Si, S, and Ar abundances. The X-ray filaments, spatially correlated with the 24 μ {{m}} IR filaments, are suggested to be due to the SNR shock interaction with dense gas, while the halo forms from SNR breaking out into a tenuous medium. Kes 79 appears to have a double-hemisphere morphology viewed along the symmetric axis. Projection effect can explain the multiple-shell structures and the thermal composite morphology. The high-velocity, hot ({{kT}}{{h}}˜ 1.4{--}1.6 keV) ejecta patch with high metal abundances, together with the non-uniform metal distribution across the SNR, indicate an asymmetric SN explosion of Kes 79. We refine the Sedov age to 4.4-6.7 kyr and the mean shock velocity to 730 {km} {{{s}}}-1. Our multi-wavelength study suggests a progenitor mass of ˜15-20 solar masses for the core-collapse explosion that formed Kes 79 and its CCO, PSR J1852+0040.

  9. Constraints on cosmic-ray efficiency in the supernova remnant RCW 86 using multi-wavelength observations

    DOE PAGES

    Lemoine-Goumard, M.; Renaud, M.; Vink, J.; ...

    2012-08-31

    Several young supernova remnants (SNRs) have recently been detected in the high-energy (HE; 0.1 < E < 100 GeV) and very-high-energy (VHE; E > 100 GeV) gamma-ray domains. As exemplified by RX J1713.7-3946, the nature of this emission has been hotly debated, and direct evidence for the efficient acceleration of cosmic-ray protons at the SNR shocks still remains elusive. Here, we study the broadband gamma-ray emission from one of these young SNRs, namely RCW 86, for which several observational lines of evidence indirectly point towards the presence of accelerated hadrons. We then attempt to detect any putative hadronic signal from this SNR in the available gamma-ray data, in order to assess the level of acceleration efficiency. We also analyzed more than 40 months of data acquired by the Large Area Telescope (LAT) on-board the Fermi Gamma-Ray Space Telescope in the HE domain, and gathered all of the relevant multi-wavelength (from radio to VHE gamma-rays) information about the broadband nonthermal emission from RCW 86. For this purpose, we re-analyzed the archival X-ray data from the ASCA/Gas Imaging Spectrometer (GIS), the XMM-Newton/EPIC-MOS, and the RXTE/Proportional Counter Array (PCA). Beyond the expected Galactic diffuse background, no significant gamma-ray emission in the direction of RCW 86 is detected in any of the 0.1–1, 1–10 and 10–100 GeV Fermi-LAT maps. The derived HE upper limits, together with the H.E.S.S. measurements in the VHE domain, are incompatible with a standard Dmore » $$-2\\atop{p}$$ hadronic emission arising from proton-proton interactions, and can only be accommodated by a spectral index Γ ≤ 1.8, i.e. a value in-between the standard (test-particle) index and the asymptotic limit of theoretical particle spectra in the case of strongly modified shocks. In such a hadronic scenario, the total energy in accelerated particles is at the level of ηCR = ECR/ESN ~0.07 d$$2\\atop{2.5}$$kpc/$$\\tilde{n}$$ (with the distance d2.5 kpc ≡ d/2

  10. Vertical profiling of geometrical, optical and microphysical particle properties over Nothern India using a multi-wavelength lidar system

    NASA Astrophysics Data System (ADS)

    Giannakaki, E.; Mielonen, T.; Korhonen, K.; Lihavainen, H.; Hyvarinen, A.; Mueller, D.; Baars, H.; Engelmann, R.; Dietrich, A.; Hooda, R. K.; Sharma, V.; Lehtinen, K. E.; Viisanen, Y.; Komppula, M.

    2012-12-01

    A one-year-long campaign of Raman lidar measurements has been performed in Gual Pahari (30 km from Delhi), India in the frame of EUCAARI (European Integrated project on Aerosol Cloud Climate and Air Quality interactions) project. The measurements were performed from March 2008 to March 2009 with a multi-wavelength Raman lidar of the type PollyXT. The lidar measurements were carried out continuously and during one year we have selected 183 days with almost 2500 hours of measurement time in total. The range-corrected backscatter signal at 1064nm is used to determine the geometrical boundaries of aerosol layers for each of the one-hour period averaged data. Then we identify the main source of the identified atmospheric layers using backward trajectory analyses with HYSPLIT. Back-trajectory analysis has revealed the advection of different types of aerosols. The seasonal cycle of geometrical, optical and microphysical properties over Northern India was observed. The profiles of the backscatter coefficients show a clear seasonal variation. The summer had the largest mean backscatter coefficient, averaged between 1 and 3 km height, while the winter had the lowest backscatter values. The seasonal profiles of backscatter coefficients had distinctly different shapes. In summer, the values of these coefficients had the steepest decrease from 1 to 3 km. The autumn, and especially the winter, had a relatively shallow aerosol layer near the ground. The value of the backscatter coefficient was highest near the ground and then it decreased moderately with increasing altitude. The main seasonal variation of extinction coefficients followed in a similar fashion. The seasonal averages of the lidar ratios at 355 nm varied from 45 sr in the spring to 77 sr in the autumn, and the corresponding variability at 532 nm was from 36 to 60 sr. The lidar ratios at 532 nm were below 40 sr in the spring and winter, indicating the presence of a cleaner air mass with relatively more aged aerosols

  11. Constraints on cosmic-ray efficiency in the supernova remnant RCW 86 using multi-wavelength observations

    SciTech Connect

    Lemoine-Goumard, M.; Renaud, M.; Vink, J.; Allen, G. E.; Bamba, A.; Giordano, F.; Uchiyama, Y.

    2012-08-31

    Several young supernova remnants (SNRs) have recently been detected in the high-energy (HE; 0.1 < E < 100 GeV) and very-high-energy (VHE; E > 100 GeV) gamma-ray domains. As exemplified by RX J1713.7-3946, the nature of this emission has been hotly debated, and direct evidence for the efficient acceleration of cosmic-ray protons at the SNR shocks still remains elusive. Here, we study the broadband gamma-ray emission from one of these young SNRs, namely RCW 86, for which several observational lines of evidence indirectly point towards the presence of accelerated hadrons. We then attempt to detect any putative hadronic signal from this SNR in the available gamma-ray data, in order to assess the level of acceleration efficiency. We also analyzed more than 40 months of data acquired by the Large Area Telescope (LAT) on-board the Fermi Gamma-Ray Space Telescope in the HE domain, and gathered all of the relevant multi-wavelength (from radio to VHE gamma-rays) information about the broadband nonthermal emission from RCW 86. For this purpose, we re-analyzed the archival X-ray data from the ASCA/Gas Imaging Spectrometer (GIS), the XMM-Newton/EPIC-MOS, and the RXTE/Proportional Counter Array (PCA). Beyond the expected Galactic diffuse background, no significant gamma-ray emission in the direction of RCW 86 is detected in any of the 0.1–1, 1–10 and 10–100 GeV Fermi-LAT maps. The derived HE upper limits, together with the H.E.S.S. measurements in the VHE domain, are incompatible with a standard D$-2\\atop{p}$ hadronic emission arising from proton-proton interactions, and can only be accommodated by a spectral index Γ ≤ 1.8, i.e. a value in-between the standard (test-particle) index and the asymptotic limit of theoretical particle spectra in the case of strongly modified shocks. In such a hadronic scenario, the total energy in accelerated particles is at the level of ηCR = ECR/ESN ~0.07 d$2\\atop{2.5}$kpc/$\\tilde{n}$ (with the distance d2.5 kpc ≡ d/2

  12. POISSON project. II. A multi-wavelength spectroscopic and photometric survey of young protostars in L 1641

    NASA Astrophysics Data System (ADS)

    Caratti o Garatti, A.; Garcia Lopez, R.; Antoniucci, S.; Nisini, B.; Giannini, T.; Eislöffel, J.; Ray, T. P.; Lorenzetti, D.; Cabrit, S.

    2012-02-01

    Context. Characterising stellar and circumstellar properties of embedded young stellar objects (YSOs) is mandatory for understanding the early stages of the stellar evolution. This task requires the combination of both spectroscopy and photometry, covering the widest possible wavelength range, to disentangle the various protostellar components and activities. Aims: As part of the POISSON project (Protostellar Optical-Infrared Spectral Survey On NTT), we present a multi-wavelength spectroscopic and photometric investigation of embedded YSOs in L 1641, aimed to derive the stellar parameters and evolutionary stages and to infer their accretion properties. Methods: Our multi-wavelength database includes low-resolution optical-IR spectra from the NTT and Spitzer (0.6-40 μm) and photometric data covering a spectral range from 0.4 to 1100 μm, which allow us to construct the YSOs spectral energy distributions (SEDs) and to infer the main stellar parameters (visual extinction, spectral type, accretion, stellar, bolometric luminosity, mass accretion, and ejection rates). Results: The NTT optical-NIR spectra are rich in emission lines, which are mostly associated with YSO accretion, ejection, and chromospheric activities. A few emission lines, prominent ice (H2O and CO2), and amorphous silicate absorption features have also been detected in the Spitzer spectra. The SED analysis allows us to group our 27 YSOs into nine Class I, eleven Flat, and seven Class II objects. However, on the basis of the derived stellar properties, only six Class I YSOs have an age of ~105 yr, while the others are older (5 × 105-106 yr), and, among the Flat sources, three out of eleven are more evolved objects (5 × 106-107 yr), indicating that geometrical effects can significantly modify the SED shapes. Inferred mass accretion rates (Ṁacc) show a wide range of values (3.6 × 10-9 to 1.2 × 10-5 M⊙ yr-1), which reflects the age spread observed in our sample well. Average values of mass

  13. Quasi-periodic pulsations with varying period in multi-wavelength observations of an X-class flare

    SciTech Connect

    Huang, Jing; Tan, Baolin; Zhang, Yin; Karlický, Marian; Mészárosová, Hana

    2014-08-10

    This work presents an interesting phenomenon of the period variation in quasi-periodic pulsations (QPPs) observed during the impulsive phase of a coronal mass ejection-related X1.1 class flare on 2012 July 6. The period of QPPs was changed from 21 s at soft X-rays (SXR) to 22-23 s at microwaves, to ∼24 s at extreme ultraviolet emissions (EUV), and to 27-32 s at metric-decimetric waves. The microwave, EUV, and SXR QPPs, emitted from flare loops of different heights, were oscillating in phase. Fast kink mode oscillations were proposed to be the modulation mechanism, which may exist in a wide region in the solar atmosphere from the chromosphere to the upper corona or even to the interplanetary space. Changed parameters of flare loops through the solar atmosphere could result in the varying period of QPPs at different wavelengths. The first appearing microwave QPPs and quasi-periodic metric-decimetric type III bursts were generated by energetic electrons. This may imply that particle acceleration or magnetic reconnection were located between these two non-thermal emission sources. Thermal QPPs (in SXR and EUV emissions) occurred later than the nonthermal ones, which would suggest a some time for plasma heating or energy dissipation in flare loops during burst processes. At the beginning of flare, a sudden collapse and expansion of two separated flare loop structures occurred simultaneously with the multi-wavelength QPPs. An implosion in the corona, including both collapse and expansion of flare loops, could be a trigger of loop oscillations in a very large region in the solar atmosphere.

  14. Multi-wavelength Observations of the Black Widow Pulsar 2FGL J2339.6-0532 with OISTER and Suzaku

    NASA Astrophysics Data System (ADS)

    Yatsu, Yoichi; Kataoka, Jun; Takahashi, Yosuke; Tachibana, Yutaro; Kawai, Nobuyuki; Shibata, Shimpei; Pike, Sean; Yoshii, Taketoshi; Arimoto, Makoto; Saito, Yoshihiko; Nakamori, Takeshi; Sekiguchi, Kazuhiro; Kuroda, Daisuke; Yanagisawa, Kenshi; Hanayama, Hidekazu; Watanabe, Makoto; Hamamoto, Ko; Nakao, Hikaru; Ozaki, Akihito; Motohara, Kentaro; Konishi, Masahiro; Tateuchi, Ken; Matsunaga, Noriyuki; Morokuma, Tomoki; Nagayama, Takahiro; Murata, Katsuhiro; Akitaya, Hiroshi; Yoshida, Michitoshi; Ali, Gamal B.; Essam Mohamed, A.; Isogai, Mizuki; Arai, Akira; Takahashi, Hidenori; Hashimoto, Osamu; Miyanoshita, Ryo; Omodaka, Toshihiro; Takahashi, Jun; Tokimasa, Noritaka; Matsuda, Kentaro; Okumura, Shin-ichiro; Nishiyama, Kota; Urakawa, Seitaro; Nogami, Daisaku; Oasa, Yumiko; OISTER Team

    2015-04-01

    Multi-wavelength observations of the black widow binary system 2FGL J2339.6-0532 are reported. The Fermi gamma-ray source 2FGL J2339.6-0532 was recently categorized as a black widow in which a recycled millisecond pulsar (MSP) is evaporating the companion star with its powerful pulsar wind. Our optical observations show clear sinusoidal light curves due to the asymmetric temperature distribution of the companion star. Assuming a simple geometry, we constrained the range of the inclination angle of the binary system to 52{}^\\circ \\lt i\\lt 59{}^\\circ , which enables us to discuss the interaction between the pulsar wind and the companion in detail. The X-ray spectrum consists of two components: a soft, steady component that seems to originate from the surface of the MSP, and a hard, variable component from the wind-termination shock near the companion star. The measured X-ray luminosity is comparable to the bolometric luminosity of the companion, meaning that the heating efficiency is less than 0.5. In the companion orbit, 1011 cm from the pulsar, the pulsar wind is already in the particle-dominant stage with a magnetization parameter of σ \\lt 0.1. In addition, we precisely investigated the time variations of the X-ray periodograms and detected a weakening of the orbital modulation. The observed phenomenon may be related to unstable pulsar wind activity or weak mass accretion, both of which can result in the temporal extinction of the radio pulse.

  15. Multi-wavelength properties and smbh's masses of the isolated galaxies with active nuclei in the Local Universe

    NASA Astrophysics Data System (ADS)

    Vavilova, Iryna; Vasylenko, Anatolij; Babyk, Iuri; Pulatova, Nadya

    2016-07-01

    We apply the specially-oriented Astro-Space databases obtained with ground-based telescopes and space observatories to study the multi-wavelength spectral and physical properties of galaxies with active nuclei (AGNs), namely of isolated AGNs that are poorly investigated especially in X-rays. Such a study allowed us 1) to separate the internal evolution mechanisms from the environment influence and consider them as two separate processes related to fueling nuclear activity, 2) to explore absorption features and the X-ray continuum radiation from accretion disks around SMBHs (e.g. to select accretion models). In the case of detecting the Fe K emission line, it was possible to analyze the physical conditions in the AGNs innermost parts in more details. Using the SDSS spectral Hβ-line data we were able to estimate the SMBH masses of several isolated AGNs in the Local Universe, which are systematically lower than the SMBH masses of AGNs located in a dense environment. We present also the results of analysis of the spectral data obtained by XMM-Newton, Swift, Chandra, and INTEGRAL space observatories for several isolated AGNs from 2MIG catalogue, for which the available X-ray data were accessed. Among these objects are CGCG 179-005, NGC 6300, NGC 1050, NGC 2989, WKK 3050, ESO 438-009, ESO 317-038 and others. We determined corresponding spectral models and values of their parameters (spectral index, intrinsic absorption etc.). X-ray spectra for bright galaxies, NGC 6300 and Circinus, were analyzed up to 250 keV and their characteristics of emission features were determined in 6-7 keV range.

  16. Space and ground-based multi-wavelength observing campaign of Jupiter's aurora and the Io Plasma Torus

    NASA Astrophysics Data System (ADS)

    Branduardi-Raymont, G.; Yoshikawa, I.; Badman, S.

    2013-09-01

    The EXCEED EUV spectrograph (55 - 145 nm) on-board the Japanese mission Sprint-A, due for launch into low Earth orbit in August 2013, will be dedicated to the study of the tenuous plasma surrounding planets in our solar system. A target of special interest will be Jupiter and its environment, and the emission from the Io Plasma Torus (IPT) in particular. A systematic campaign of observations of Jupiter and the IPT is planned over the period Oct. 2013 - March 2014. This is a unique opportunity to explore the possible links between the IPT emission distribution, the strength and character of Jupiter's auroral emissions and the conditions of the solar wind. Hence, concurrently with the EXCEED observations, a large multi-wavelength campaign has been organised to exploit this unique opportunity of gathering important diagnostic data on the complex array of physical processes taking place in Jupiter's environment. This campaign includes (this is by no means a complete list) approved FUV imaging and spectroscopy of Jupiter's Northern aurora with HSTSTIS (PI: Sarah Badman), Kitt Peak 4m visible spectroscopy of the IPT (PI: Sarah Badman), Gemini observations of Jupiter H3+ (4 µm) aurora (PI: Melin), submitted proposals for HST-STIS FUV observations of Jupiter's Southern aurora, Io and Ganymede's footprints (PI: Bonfond), Chandra and XMM-Newton pointings of Jupiter and the IPT (PI: Kraft), Suzaku observations of diffuse X-rays from the Jovian inner magnetosphere (PI: Ezoe); in addition, ground based observations with IRTF, Subaru and other facilities are planned. This talk will review the motivation for this vaste coordinated observing campaign, and the science that we expect to draw from it: essentially a better understanding of how the Jupiter's system works.

  17. Continuous vertical aerosol profiling with a multi-wavelength Raman polarization lidar over the Pearl River Delta, China

    NASA Astrophysics Data System (ADS)

    Heese, Birgit; Baars, Holger; Bohlmann, Stephanie; Althausen, Dietrich; Deng, Ruru

    2017-06-01

    A dataset of particle optical properties of the highly polluted atmosphere over the Pearl River Delta (PRD), Guangzhou, China, is presented in this paper. The data were derived from the measurements of a multi-wavelength Raman and depolarization lidar PollyXT and a co-located AERONET sun photometer. The measurement campaign was conducted from November 2011 to mid-June 2012. These are the first Raman lidar measurements in the PRD that lasted for several months. A mean value of aerosol optical depth (AOD) of 0.54 ± 0.33 was observed by the sun photometer at 500 nm in the polluted atmosphere over this megacity for the whole measurement period. The lidar profiles frequently show lofted aerosol layers, which reach altitudes of up to 2 to 3 km and, especially during the spring season, up to 5 km. These layers contain between 12 and 56 % of the total AOD, with the highest values in spring. The aerosol types in these lofted layers are classified by their optical properties. The observed lidar ratio values range from 30 to 80 sr with a mean value of 48.0 ± 10.7 sr at 532 nm. The linear particle depolarization ratio at 532 nm lies mostly below 5 %, with a mean value of 3.6 ± 3.7 %. The majority of the Ångström exponents lie between 0.5 and 1.5, indicating a mixture of fine- and coarse-mode aerosols. These results reveal that mostly urban pollution particles mixed with particles produced from biomass and industrial burning are present in the atmosphere above the Pearl River Delta. Trajectory analyses show that these pollution mixtures arise mainly from local and regional sources.

  18. Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained

    NASA Astrophysics Data System (ADS)

    Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Braun, I.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido, D.; Giavitto, G.; Godinović, N.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Huber, B.; Jogler, T.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, A.; López, M.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Uellenbeck, M.; Vankov, H.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.

    2012-06-01

    Context. The blazar Markarian 421 is one of the brightest TeV gamma-ray sources of the northern sky. From December 2007 until June 2008 it was intensively observed in the very high energy (VHE, E > 100 GeV) band by the single-dish Major Atmospheric Gamma-ray Imaging Cherenkov telescope (MAGIC-I). Aims: We aimed to measure the physical parameters of the emitting region of the blazar jet during active states. Methods: We performed a dense monitoring of the source in VHE with MAGIC-I, and also collected complementary data in soft X-rays and optical-UV bands; then, we modeled the spectral energy distributions (SED) derived from simultaneous multi-wavelength data within the synchrotron self-Compton (SSC) framework. Results: The source showed intense and prolonged γ-ray activity during the whole period, with integral fluxes (E > 200 GeV) seldom below the level of the Crab Nebula, and up to 3.6 times this value. Eight datasets of simultaneous optical-UV (KVA, Swift/UVOT), soft X-ray (Swift/XRT) and MAGIC-I VHE data were obtained during different outburst phases. The data constrain the physical parameters of the jet, once the spectral energy distributions obtained are interpreted within the framework of a single-zone SSC leptonic model. Conclusions: The main outcome of the study is that within the homogeneous model high Doppler factors (40 ≤ δ ≤ 80) are needed to reproduce the observed SED; but this model cannot explain the observed short time-scale variability, while it can be argued that inhomogeneous models could allow for less extreme Doppler factors, more intense magnetic fields and shorter electron cooling times compatible with hour or sub-hour scale variability.

  19. A MULTI-WAVELENGTH POLARIMETRIC STUDY OF THE BLAZAR CTA 102 DURING A GAMMA-RAY FLARE IN 2012

    SciTech Connect

    Casadio, Carolina; Gómez, José L.; Agudo, Iván; Molina, Sol N.; Jorstad, Svetlana G.; Marscher, Alan P.; Bala, Vishal; Joshi, Manasvita; Taylor, Brian; Williamson, Karen E.; Larionov, Valeri M.; Blinov, Dmitry A.; Grishina, Tatiana S.; Hagen-Thorn, Vladimir A.; Smith, Paul S.; Gurwell, Mark A.; Lähteenmäki, Anne; Arkharov, Arkady A.; Borman, George A.; Paola, Andrea Di; and others

    2015-11-01

    We perform a multi-wavelength polarimetric study of the quasar CTA 102 during an extraordinarily bright γ-ray outburst detected by the Fermi Large Area Telescope in 2012 September–October when the source reached a flux of F{sub >100} {sub MeV} = 5.2 ± 0.4 × 10{sup −6} photons cm{sup −2} s{sup −1}. At the same time, the source displayed an unprecedented optical and near-infrared (near-IR) outburst. We study the evolution of the parsec-scale jet with ultra-high angular resolution through a sequence of 80 total and polarized intensity Very Long Baseline Array images at 43 GHz, covering the observing period from 2007 June to 2014 June. We find that the γ-ray outburst is coincident with flares at all the other frequencies and is related to the passage of a new superluminal knot through the radio core. The powerful γ-ray emission is associated with a change in direction of the jet, which became oriented more closely to our line of sight (θ ∼ 1.°2) during the ejection of the knot and the γ-ray outburst. During the flare, the optical polarized emission displays intra-day variability and a clear clockwise rotation of electric vector position angles (EVPAs), which we associate with the path followed by the knot as it moves along helical magnetic field lines, although a random walk of the EVPA caused by a turbulent magnetic field cannot be ruled out. We locate the γ-ray outburst a short distance downstream of the radio core, parsecs from the black hole. This suggests that synchrotron self-Compton scattering of NIR to ultraviolet photons is the probable mechanism for the γ-ray production.

  20. Multi-Wavelength Spectroscopic Observations of a White Light Flare Produced Directly by Non-thermal Electrons

    NASA Astrophysics Data System (ADS)

    Lee, Kyoung-Sun; Imada, Shinsuke; Watanabe, Kyoko; Bamba, Yumi; Brooks, David

    2017-08-01

    An X1.6 flare on 2014 October 22 was observed by multiple spectrometers in UV, EUV and X-ray (Hinode/EIS, IRIS, and RHESSI), and multi-wavelength imaging observations (SDO/AIA and HMI). We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode/EIS, we measure the temporal variation of the plasma properties in the bright kernel in the chromosphere and corona. We find that explosive evaporation was observed when the WL emission occurred. The temporal correlation of the WL emission, HXR peak, and evaporation flows indicates that the WL emission was produced by accelerated electrons. We calculated the energy flux deposited by non-thermal electrons (observed by RHESSI) and compared it to the dissipated energy estimated from a chromospheric line (Mg II triplet) observed by IRIS. The deposited energy flux from the non-thermal electrons is about (3-7.7)x1010 erg cm-2 s-1 for a given low-energy cutoff of 30-40 keV, assuming the thick-target model. The energy flux estimated from the changes in temperature in the chromosphere measured using the Mg II subordinate line is about (4.6-6.7)×109 erg cm-2 s-1: ˜6%-22% of the deposited energy. This comparison of estimated energy fluxes implies that the continuum enhancement was directly produced by the non-thermal electrons.

  1. Multi-wavelength Erbium-doped fiber laser based on four-wave-mixing effect in single mode fiber and high nonlinear fiber.

    PubMed

    Wang, Pinghe; Weng, Danmei; Li, Kun; Liu, Yong; Yu, Xuecai; Zhou, Xiaojun

    2013-05-20

    A multi-wavelength Erbium-doped fiber (EDF) laser based on four-wave-mixing is proposed and experimentally demonstrated. The 5 km single mode fiber in the cavity enhances the four-wave-mixing to suppress the homogenous broadening of the erbium-doped fiber and get the stable multi-wavelength comb. The lasing stability is investigated. When the pump power is 300 mW, the fiber laser has 5-lasing lines and the maximum fluctuation of the output power is about 3.18 dB. At the same time, a laser with 110 m high nonlinear fiber (HNFL) is demonstrated. When the pump power is 300 mW, it has 7-lasing lines (above -30 dBm) and the maximum fluctuation is 0.18dB.

  2. Based-on generalized neural network multi-wavelength conversion technique of laser and its influence study on target detection ranges

    NASA Astrophysics Data System (ADS)

    Liu, Zhonghua; Wu, Ronghua; Huang, Gaoming

    2017-02-01

    The equation of laser detection system range and multi-wavelength conversion technique were used to calculate the maximum detection range under different meteorological conditions. A new algorithm was proposed to solve the detection range implicit function equation, by which the accurate arithmetic solution could be got quickly. When solving the detection range implicit function equation, the atmospheric transmittance is the function of range, the multiwavelength atmospheric extinction coefficients were calculated with neural network conversion model. Then the equation was solved by linear interpolation and iteration methods, the iteration initial value was estimated with numeric method. This algorithm is valuable for simulating, model building and designing of multi-wavelength laser system under different seasons and atmospheric circumstance.

  3. Improving the nonlinear energy conversion efficiency of a Kerr-comb-based broadband multi-wavelength light source by introducing an optical feedback loop

    NASA Astrophysics Data System (ADS)

    Lei, Xun; Chen, Shaowu; Zhang, Libin

    2017-06-01

    We simulate the generation of microcavity solitons in Kerr combs, evaluate their characteristics in the frequency domain via the Lugiato-Lefever equation (LLE), and optimize their shapes in the time domain by changing some related parameters to flatten the spectrum of the optical frequency combs and improve the nonlinear energy conversion efficiency of the underlying four-wave mixing process. In addition, we propose a new Kerr comb generation scheme to obtain an energy-efficient multi-wavelength light source by introducing an optical feedback loop with phase control in the pumping system. The simulation results show that the proposed scheme can enhance the nonlinear energy conversion efficiency of the multi-wavelength source and reduce the pump power level by about 32%.

  4. A multi-wavelength fiber-optic temperature-controlled laser soldering system for upper aerodigestive tract reconstruction: an animal model.

    PubMed

    Abergel, Avraham; Gabay, Ilan; Fliss, Dan M; Katzir, Abraham; Gil, Ziv

    2011-06-01

    Laser soldering of a thick multilayer organ using conventional CO(2) lasers is ineffective. The purpose of this work was to develop a method for bonding the multilayer tissue of the upper aerodigestive tracts (UADT) without the need of sutures or stapling. Animal model. Academic research laboratory. The authors developed a multi-wavelength laser system, based on 2 fiber-optic lasers applied simultaneously. A highly absorbable CO(2) laser interacts with the muscular layer, and a nonabsorbable GaAs laser interacts with indocyanine-green solid albumin, placed between the mucosa and the muscular layer. The authors used an ex vivo porcine model to examine the capability of this system to effectively correct esophageal tears. The soldered esophagi burst pressure was >175 cm H(2)O (98% success rate) in 88 of the 90 experiments. A conventional CO(2) laser soldering resulted in insufficient bonding (mean burst pressure of 40 ± 7 cm H(2)O, n = 5), while the multi-wavelength laser system provided an ~9-fold tighter seal (359 ± 75.4 cm H(2)O, P < .0001, n = 15). Burst pressures after conventional suturing of the defect was significantly lower (106 ± 65.8 cm H(2)O, P < .001) than in the multi-wavelength laser system. Bonding of the UADT mucosa using a multi-wavelength, temperature-controlled laser soldering system can support significantly higher pressures then conventional CO(2) laser soldering and suture repair. The mean bonding pressure was 3.5-fold higher than the maximal swallowing pressure. Our findings provide a basis for implementation of new surgical tools for repair of esophageal perforations.

  5. Fabrication of erbium-ytterbium distributed multi-wavelength fiber lasers by writing the superstructured fiber Bragg grating resonator in a single writing laser scan

    NASA Astrophysics Data System (ADS)

    Brochu, Guillaume; LaRochelle, Sophie

    2007-06-01

    We present an alternative method to fabricate multi-wavelength distributed-feedback fiber lasers made of superstructured chirped fiber Bragg gratings in a single writing laser scan with a custom period-profiled phase mask and a tailored amplitude apodization profile produced by phase mask dithering. This method simplifies the fabrication process and increases the yield of samples having the right number of laser lines and a small frequency error with respect to a reference grid.

  6. Topological insulator: Bi{sub 2}Se{sub 3}/polyvinyl alcohol film-assisted multi-wavelength ultrafast erbium-doped fiber laser

    SciTech Connect

    Guo, Bo; Yao, Yong Yang, Yan-Fu; Yuan, Yi-Jun; Wang, Rui-Lai; Wang, Shu-Guang; Ren, Zhong-Hua; Yan, Bo

    2015-02-14

    We experimentally demonstrate a multi-wavelength ultrafast erbium-doped fiber laser incorporating a μm-scale topological insulator: Bi{sub 2}Se{sub 3}/Polyvinyl Alcohol film as both an excellent saturable absorber for mode-locking and a high-nonlinear medium to induce a giant third order optical nonlinear effect for mitigating the mode competition of erbium-doped fiber laser and stabilizing the multi-wavelength oscillation. By properly adjusting the pump power and the polarization state, the single-, dual-, triple-, four-wavelength mode-locking pulse could be stably initiated. For the four-wavelength operation, we obtain its pulse width of ∼22 ps and a fundamental repetition rate of 8.83 MHz. The fiber laser exhibits the maximum output power of 9.7 mW with the pulse energy of 1.1 nJ and peak power of 50 W at the pump power of 155 mW. Our study shows that the simple, stable, low-cost multi-wavelength ultrafast fiber laser could be applied in various potential fields, such as optical communication, biomedical research, and radar system.

  7. INTERACT-II campaign:comparison of commercial lidars and ceilometers with advanced multi-wavelength Raman lidars

    NASA Astrophysics Data System (ADS)

    Rosoldi, Marco; Madonna, Fabio; Pappalardo, Gelsomina; Vande Hey, Joshua; Zheng, Yunhui; Vaisala Team

    2017-04-01

    Knowledge of aerosol spatio-temporal distribution in troposphere is essential for the study of climate and air quality. For this purpose, global scale high resolution continuous measurements of tropospheric aerosols are needed. Global coverage high resolution networks of ground-based low-cost and low-maintenance remote sensing instruments, such as commercial automatic lidars and ceilometers, can strongly contribute to this scientific mission. Therefore, it is very interesting for scientific community to understand to which extent these instruments are able to provide reliable aerosol measurements and fill in the geographical gaps of existing networks of the advanced lidars, like EARLINET (European Aerosol Research LIdar NETwork). The INTERACT-II (INTERcomparison of Aerosol and Cloud Tracking) campaign, carried out at CIAO (CNR-IMAA Atmospheric Observatory) in Tito Scalo, Potenza, Italy (760m a.s.l., 40.60°N, 15.72°E), aims to evaluate the performances of commercial automatic lidars and ceilometers for tropospheric aerosol profiling. The campaign has been performed in the period from July 2016 to January 2017 in the framework of ACTRIS-2 (Aerosol Clouds Trace gases Research InfraStructure) H2020 research infrastructure project. Besides the commercial ceilometers operational at CIAO (VAISALA CT25K and Luftt CHM15k), the performance of a CL51 VAISALA ceilometer, a Campbell CS135 ceilometer and a mini-Micro Pulse Lidar (MPL) have been assessed using the EARLINET multi-wavelengths Raman lidars operative at CIAO as reference. Following a similar approach used in the first INTERACT campaign (Madonna et al., AMT 2015), attenuated backscatter coefficient profiles and signals obtained from all the instruments have been compared, over a vertical resolution of 60 meters and a temporal integration ranging between 1 and 2 hours, depending on the observed atmospheric scenario. CIAO lidars signals have been processed using the EARLINET Single Calculus Chain (SCC) also with the

  8. Optical properties of mixed aerosol layers over Japan derived with multi-wavelength Mie-Raman lidar system

    NASA Astrophysics Data System (ADS)

    Hara, Yukari; Nishizawa, Tomoaki; Sugimoto, Nobuo; Matsui, Ichiro; Pan, Xiaole; Kobayashi, Hiroshi; Osada, Kazuo; Uno, Itsushi

    2017-02-01

    Mixing state of aerosols and optical properties including lidar ratio, particle depolarization ratio, and Ångström exponent were investigated at Fukuoka in western Japan using a multi-wavelength Mie-Raman lidar (MMRL), various aerosol mass-concentration measurements, and a polarization optical particle counter during Winter-Spring 2015. Aerosol extinction coefficient, backscatter coefficient, and depolarization at 355 and 532 nm and attenuated backscatter coefficient at 1064 nm are obtained from the MMRL measurements. Ten aerosol episodes were classified into three categories (air pollution, mineral dust, and marine aerosol) based on aerosol mass-concentration measurements in the fine-mode (particle diameter Dp<2.5 μm) and coarse-mode (2.5 μm

  9. A multi-wavelength scattered light analysis of the dust grain population in the GG Tau circumbinary ring

    SciTech Connect

    Duchene, G; McCabe, C; Ghez, A; Macintosh, B

    2004-02-04

    We present the first 3.8 {micro}m image of the dusty ring surrounding the young binary system GG Tau, obtained with the W. M. Keck II 10m telescope's adaptive optics system. THis is the longest wavelength at which the ring has been detected in scattered light so far, allowing a multi-wavelength analysis of the scattering proiperties of the dust grains present in this protoplanetary disk in combination with previous, shorter wavelengths, HST images. We find that the scattering phase function of the dust grains in the disk is only weakly dependent on the wavelength. This is inconsistent with dust models inferred from observations of the interstellar medium or dense molecular clouds. In particular, the strongly forward-throwing scattering phase function observed at 3.8 {micro}m implies a significant increase in the population of large ({approx}> 1 {micro}m) grains, which provides direct evidence for grain growth in the ring. However, the grain size distribution required to match the 3.8 {micro}m image of the ring is incompatible with its published 1 {micro}m polarization map, implying that the dust population is not uniform throughout the ring. We also show that our 3.8 {micro}m image of the ring is incompatible with its published 1 {micro}m polarization map, implying that the dust population is not uniform throughout the ring. We also show that our 3.8 {micro}m scattered light image probes a deeper layer of the ring than previous shorter wavelength images, as demonstrated by a shift in the location of the inner edge of the disk's scattered light distribution between 1 and 3.8 {micro}m. We therefore propose a stratified structure for the ring in which the surface layers, located {approx} 50 AU above the ring midplane, contain dust grains that are very similar to those found in dense molecular clouds, while the region of the ring located {approx} 25 AU from the midplane contains significantly larger grains. This stratified structure is likely the result of vertical

  10. MULTI-WAVELENGTH OBSERVATIONS OF 3FGL J2039.6–5618: A CANDIDATE REDBACK MILLISECOND PULSAR

    SciTech Connect

    Salvetti, D.; Mignani, R. P.; Luca, A. De; Belfiore, A.; Marelli, M.; Pizzocaro, D.; Delvaux, C.; Greiner, J.; Becker, W.; Pallanca, C.; Breeveld, A. A.

    2015-12-01

    We present multi-wavelength observations of the unassociated γ-ray source 3FGL J2039.6−5618 detected by the Fermi Large Area Telescope. The source γ-ray properties suggest that it is a pulsar, most likely a millisecond pulsar, for which neither radio nor γ-ray pulsations have been detected. We observed 3FGL J2039.6−5618 with XMM-Newton and discovered several candidate X-ray counterparts within/close to the γ-ray error box. The brightest of these X-ray sources is variable with a period of 0.2245 ± 0.0081 days. Its X-ray spectrum can be described by a power law with photon index Γ{sub X} = 1.36 ± 0.09, and hydrogen column density N{sub H} < 4 × 10{sup 20} cm{sup −2}, which gives an unabsorbed 0.3–10 keV X-ray flux of 1.02 × 10{sup −13} erg cm{sup −2} s{sup −1}. Observations with the Gamma-Ray Burst Optical/Near-Infrared Detector discovered an optical counterpart to this X-ray source, with a time-averaged magnitude g′ ∼ 19.5. The counterpart features a flux modulation with a period of 0.22748 ± 0.00043 days that coincides, within the errors, with that of the X-ray source, confirming the association based on the positional coincidence. We interpret the observed X-ray/optical periodicity as the orbital period of a close binary system where one of the two members is a neutron star. The light curve profile of the companion star, which has two asymmetric peaks, suggests that the optical emission comes from two regions with different temperatures on its tidally distorted surface. Based upon its X-ray and optical properties, we consider this source as the most likely X-ray counterpart to 3FGL J2039.6−5618, which we propose to be a new redback system.

  11. Quantifying the physical properties of high-redshift galaxies: A multi-wavelength survey on the progenitors of local galaxies

    NASA Astrophysics Data System (ADS)

    Petty, Sara Michelle

    Since the discovery of galaxies outside of the Milky Way, studies of nearby galaxies have revealed a very different population of galaxies compared to distant galaxies. My thesis has been motivated by galaxy evolution. In particular, I focus on the connection between nearby and distant galaxies, changes in morphologies with wavelength, and the physical properties of galaxies when the Universe was 1.5 (z = 4) to 6 (z = 1) Gyr old. Rest-frame far-ultraviolet morphologies of 8 nearby interacting and starburst galaxies are artificially redshifted and compared with 54 galaxies at z ˜ 1.5 and 46 galaxies at z ˜ 4. I calculated the Gini coefficient (G), the second-order moment of the brightest 20% of the galaxy's flux (M20), and the Sersic index (n). I showed that ˜20-30% of Lyman-break galaxies have structures similar to local starburst mergers, and may be driven by similar processes. I also determined that Mrk 8, NGC 3079, and NGC 7673 have structures similar to merger-like and clumpy star-forming galaxies observed at z ˜ 1.5 and 4. I selected 301 galaxies from the Ultra Deep Field parallel survey (UDF05) done with HST's infrared camera, NICMOS, to calculate their spectral energy distributions (SEDs). The galaxies are cross-matched using HST ACS and NICMOS filters, and the infrared Spitzer IRAC filters. Photometric redshifts, dust extinction, stellar masses, bolometric luminosity, starburst age and metallicity are estimated through Balmerbreak SED fitting. Comparisons of 16 photometric redshifts with spectroscopic redshifts give 75% agreement. I determined through Monte Carlo simulations that the SED parameters are robust for the redshift ranges z > 1.2. I find that luminosities and star formation rates increase with redshift for a subsample of galaxies at z ˜ 1.5 and z ˜ 4. I demonstrate that multi-wavelength analysis is fundamental to the understanding of galaxy evolution. I determined that G-M20 values of Balmer-break galaxies are more bulge-like in the rest

  12. A multi-wavelength investigation of the radio-loud supernova PTF11qcj and its circumstellar environment

    SciTech Connect

    Corsi, A.; Ofek, E. O.; Gal-Yam, A.; Xu, D.; Frail, D. A.; Kulkarni, S. R.; Horesh, A.; Carpenter, J.; Arcavi, I.; Cao, Y.; Mooley, K.; Sesar, B.; Fox, D. B.; Kasliwal, M. M.; Sullivan, M.; Maguire, K.; Pan, Y.-C.; Cenko, S. B.; Sternberg, A.; Bersier, D.; and others

    2014-02-10

    We present the discovery, classification, and extensive panchromatic (from radio to X-ray) follow-up observations of PTF11qcj, a supernova (SN) discovered by the Palomar Transient Factory (PTF). Our observations with the Karl G. Jansky Very Large Array show that this event is radio-loud: PTF11qcj reached a radio peak luminosity comparable to that of the famous gamma-ray-burst-associated SN 1998bw (L {sub 5} {sub GHz} ≈ 10{sup 29} erg s{sup –1} Hz{sup –1}). PTF11qcj is also detected in X-rays with the Chandra Observatory, and in the infrared band with Spitzer. Our multi-wavelength analysis probes the SN interaction with circumstellar material. The radio observations suggest a progenitor mass-loss rate of ∼10{sup –4} M {sub ☉} yr{sup –1} × (v{sub w} /1000 km s{sup –1}), and a velocity of ≈0.3-0.5 c for the fastest moving ejecta (at ≈10 days after explosion). However, these estimates are derived assuming the simplest model of SN ejecta interacting with a smooth circumstellar wind, and do not account for possible inhomogeneities in the medium and asphericity of the explosion. The radio data show deviations from such a simple model, as well as a late-time re-brightening. The X-ray flux from PTF11qcj is compatible with the high-frequency extrapolation of the radio synchrotron emission (within the large uncertainties). A light echo from pre-existing dust is in agreement with our infrared data. Our pre-explosion data from the PTF suggest that a precursor eruption of absolute magnitude M{sub r} ≈ –13 mag may have occurred ≈2.5 yr prior to the SN explosion. Overall, PTF11qcj fits the expectations from the explosion of a Wolf-Rayet star. Precursor eruptions may be a feature characterizing the final pre-explosion evolution of such stars.

  13. Star Formation in the Filamentary Dark Cloud GF-9: a Multi-Wavelength Intra-Cloud Comparative Study

    NASA Astrophysics Data System (ADS)

    Ciardi, David Robert

    Filamentary dark clouds (FDCs) are a subclass of small molecular clouds containing small numbers of somewhat regularly spaced dense cores connected by lower density gas and dust. Most of the previous work performed on FDCs has concerned the star formation properties of individual dense cores within the FDCs and has not concerned the FDCs as entities of their own. As a result little is known about the general star formation properties of FDCs. The primary question addressed in this work is 'Within filamentary dark clouds, how does the star formation process within a core region compare to that within a filamentary region?' In order to address the above question, a multi-wavelength observational comparative study has been performed upon a representative dense core (hereafter, GF9-Core) and filamentary region (hereafter, GF9-Fila) within the FDC GF-9 (LDN 1082). At the Five College Radio Astronomy Observatory, the core and filamentary region were observed in the rotational transitions of 12CO/ (J=1/to0),/ 13CO/ (J=1/to0)/ and/ CS/ (J=2/to1) covering a region of 10' x 8'. The temperature, density and kinematic structures of the two regions were deduced from the radio imaging spectroscopy data and were used to estimate the energy balance of the regions. We also obtained 70, 100, 135 and 200 μm images from the Infrared Space Observatory (ISO) covering approximately 12' x 9' which were used to investigate the temperature and density distributions of the dust within the two regions. Finally, at the Wyoming Infrared Observatory using the Aerospace Corporation NICMOS3 camera, the core and filament were imaged in the near-infrared broadband filters J, H, and K-short covering a slightly smaller region of 7' x 7'. The near-infrared survey data were used to search for embedded Class I and Class II protostars and to investigate the density distribution of the dust. We have found that the evolutionary processes of the core region and the filament region proceed along similar

  14. PKS 2005-489 at VHE: four years of monitoring with HESS and simultaneous multi-wavelength observations

    NASA Astrophysics Data System (ADS)

    H.E.S.S. Collaboration; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Behera, B.; Benbow, W.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bühler, R.; Bulik, T.; Büsching, I.; Boutelier, T.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Costamante, L.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; O'C. Drury, L.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fiasson, A.; Förster, A.; Fontaine, G.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jung, I.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Keogh, D.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J.-P.; Lohse, T.; Marandon, V.; Martineau-Huynh, O.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Orford, K. J.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Renaud, M.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sikora, M.; Skilton, J. L.; Sol, H.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Superina, G.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Venter, L.; Vialle, J. P.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.

    2010-02-01

    Aims: Our aim is to study the very high energy (VHE; E>100 GeV) γ-ray emission from BL Lac objects and the evolution in time of their broad-band spectral energy distribution (SED). Methods: VHE observations of the high-frequency peaked BL Lac object PKS 2005-489 were made with the High Energy Stereoscopic System (HESS) from 2004 through 2007. Three simultaneous multi-wavelength campaigns at lower energies were performed during the HESS data taking, consisting of several individual pointings with the XMM-Newton and RXTE satellites. Results: A strong VHE signal, ~17σ total, from PKS 2005-489 was detected during the four years of HESS observations (90.3 h live time). The integral flux above the average analysis threshold of 400 GeV is ~3% of the flux observed from the Crab Nebula and varies weakly on time scales from days to years. The average VHE spectrum measured from ~300 GeV to ~5 TeV is characterized by a power law with a photon index, Γ = 3.20± 0.16_stat± 0.10_syst. At X-ray energies the flux is observed to vary by more than an order of magnitude between 2004 and 2005. Strong changes in the X-ray spectrum (ΔΓX ≈ 0.7) are also observed, which appear to be mirrored in the VHE band. Conclusions: The SED of PKS 2005-489, constructed for the first time with contemporaneous data on both humps, shows significant evolution. The large flux variations in the X-ray band, coupled with weak or no variations in the VHE band and a similar spectral behavior, suggest the emergence of a new, separate, harder emission component in September 2005. Supported by CAPES Foundation, Ministry of Education of Brazil.Now at Harvard-Smithsonian Center for Astrophysics, Cambridge, USA.Now at W.W. Hansen Experimental Physics Laboratory & Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, USA.

  15. Multi-wavelength observations of galaxy clusters: Population evolution and scaling relations for intermediate-redshift clusters

    NASA Astrophysics Data System (ADS)

    Connor, Thomas Patrick

    Galaxy clusters are key signatures of the formation of structure in the Universe due to their positions at the nodes of the cosmic web. However, these privileged positions feature significant amounts of activity as a consequence of frequent accretion and collisions with other galaxies and clusters of galaxies. Thus, a rigorous understanding of cluster evolution constrains not only cosmological structure formation but also galaxy dynamics in the most extreme environments. Here, we examine the evolution of clusters in two situations: how the properties of the hot intracluster gas changes with the total masses of the clusters at the observational frontiers of mass and redshift; and how cluster galaxies evolve with redshift in some of the most massive clusters in the Universe. In Chapter 2 we examine a population of moderate-luminosity clusters at intermediate redshifts using the XMM-Newton telescope with well-determined masses from Hubble Space Telescope (HST) observations. We find that these systems do not deviate from scaling relations between mass, luminosity, and temperature derived from more massive clusters, implying that, even at the redshifts and masses probed here, gravitational energetics still dominate over supernovae. In Chapter 3 we utilize new techniques to maximize a multi-wavelength dataset from HST of 25 massive galaxy clusters. We present new methods for detection and photometry of galaxies in the presence of inconsistent, diffuse background. Using these techniques, we construct a photometric catalog down to M* + 4-5 for clusters at redshift z 0:2 to z 0:9, which we validate with comparisons to spectral observations and a similar catalog. We also consider the luminosity function for these clusters; we find a drop-off in the faint-end slope when only selecting red sequence galaxies. Finally, in Chapter 4, we exploit our new photometric catalogs to study the evolution of the red galaxies, the "red sequence of galaxies," in these massive clusters of

  16. Vertical profiling of Asian dust with multi-wavelength aerosol depolarization Raman lidar in Gwangju, Korea during DRAGON

    NASA Astrophysics Data System (ADS)

    Shin, D.; Mueller, D.; Noh, Y.; Shin, S.; Kim, Y. J.

    2013-12-01

    The Distributed Regional Aerosol Gridded Observation Networks (DRAGON) campaign, which was carried out in Korea from March to May 2013, aimed at validating satellite remote sensing data of aerosol optical and microphysical parameters. Anthropogenic pollution and Asian dust from the East Asian Mainland prevailed over the Korean peninsula during the DRAGON campaign. Validation of the data products requires knowledge on the vertical distribution of aerosol pollution and the knowledge of aerosol types, e.g., urban haze and dust. For this purpose we operated a multi-wavelength aerosol depolarization Raman lidar on the campus of the Gwangju Institute of Science and Technology (GIST) in Gwangju, Korea (35.10° N, 126.53° E). The system provides us with particle backscatter coefficients at 355, 532 and 1064 nm, extinction coefficients at 355 and 532nm, and the linear particle depolarization ratio at 532nm. Two upgraded sun photometers of the Aerosol Robotic Network (AERONET) with improved capabilities for dust measurements were also deployed. In our contribution we will present optical properties of Asian dust on the basis of lidar and sun photometer observations. One sun photometer was equipped with a measurement channel at 1640 nm channel and the second sun photometer carried out polarization measurements. Data could be collected on thirty-eight days We analyzed the geometrical and optical properties of Asian dust on the basis of backward trajectories in order to identify the main source regions of the observed dust layers. The height resolved statistical analysis of the DRAGON dataset reveals that the geometrical depth of the Asian dust layers was between 1 km and 4 km in 72% of all cases. Geometrical depths above 4 km were found in 20% of all cases. We found geometrical depths of 10 km in 3.3% of all cases. The vertical distribution of the dust layers was typically located in two different heights. In 51.5% of the measurements we observed Asian dust between 4 and 11km

  17. Multi-wavelength Observations of 3FGL J2039.6-5618: A Candidate Redback Millisecond Pulsar

    NASA Astrophysics Data System (ADS)

    Salvetti, D.; Mignani, R. P.; De Luca, A.; Delvaux, C.; Pallanca, C.; Belfiore, A.; Marelli, M.; Breeveld, A. A.; Greiner, J.; Becker, W.; Pizzocaro, D.

    2015-12-01

    We present multi-wavelength observations of the unassociated γ-ray source 3FGL J2039.6-5618 detected by the Fermi Large Area Telescope. The source γ-ray properties suggest that it is a pulsar, most likely a millisecond pulsar, for which neither radio nor γ-ray pulsations have been detected. We observed 3FGL J2039.6-5618 with XMM-Newton and discovered several candidate X-ray counterparts within/close to the γ-ray error box. The brightest of these X-ray sources is variable with a period of 0.2245 ± 0.0081 days. Its X-ray spectrum can be described by a power law with photon index ΓX = 1.36 ± 0.09, and hydrogen column density NH < 4 × 1020 cm-2, which gives an unabsorbed 0.3-10 keV X-ray flux of 1.02 × 10-13 erg cm-2 s-1. Observations with the Gamma-Ray Burst Optical/Near-Infrared Detector discovered an optical counterpart to this X-ray source, with a time-averaged magnitude g‧ ˜ 19.5. The counterpart features a flux modulation with a period of 0.22748 ± 0.00043 days that coincides, within the errors, with that of the X-ray source, confirming the association based on the positional coincidence. We interpret the observed X-ray/optical periodicity as the orbital period of a close binary system where one of the two members is a neutron star. The light curve profile of the companion star, which has two asymmetric peaks, suggests that the optical emission comes from two regions with different temperatures on its tidally distorted surface. Based upon its X-ray and optical properties, we consider this source as the most likely X-ray counterpart to 3FGL J2039.6-5618, which we propose to be a new redback system.

  18. A bright coronal downflow seen in multi-wavelength observations: evidence of a bifurcating flux-rope?

    NASA Astrophysics Data System (ADS)

    Tripathi, D.; Solanki, S. K.; Mason, H. E.; Webb, D. F.

    2007-09-01

    Aims:We study the origin and characteristics of a bright coronal downflow seen after a coronal mass ejection associated with erupting prominences on 5 March 2000. Methods: This study extends that of Tripathi et al. (2006b, A&A, 449, 369) based on the Extreme-ultraviolet Imaging Telescope (EIT), the Soft X-ray Telescope (SXT) and the Large Angle Spectrometric Coronagraph (LASCO) observations. We combined those results with an analysis of the observations taken by the Hα and the Mk4 coronagraphs at the Mauna Loa Solar Observatory (MLSO). The combined data-set spans a broad range of temperature as well as continuous observations from the solar surface out to 30 R⊙. Results: The downflow started at around 1.6 R⊙ and contained both hot and cold gas. The downflow was observed in the Hα and the Mk4 coronagraphs as well as the EIT and the SXT and was approximately co-spatial and co-temporal providing evidence of multi-thermal plasma. The Hα and Mk4 images show cusp-shaped structures close to the location where the downflow started. Mk4 observations reveal that the speed of the downflow in the early phase was substantially higher than the free-fall speed, implying a strong downward acceleration near the height at which the downflow started. Conclusions: The origin of the downflow was likely to have been magnetic reconnection taking place inside the erupting flux rope that led to its bifurcation. Movies are available in electronic form at http://www.aanda.org

  19. THE 2010 VERY HIGH ENERGY {gamma}-RAY FLARE AND 10 YEARS OF MULTI-WAVELENGTH OBSERVATIONS OF M 87

    SciTech Connect

    Abramowski, A.; Acero, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; Behera, B.; Birsin, E.; Biteau, J.; Bolmont, J.; Collaboration: H.E.S.S. Collaboration; MAGIC Collaboration; VERITAS Collaboration; and others

    2012-02-20

    The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 - 6) Multiplication-Sign 10{sup 9} M{sub Sun }) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) {gamma}-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE {gamma}-ray emitter since 2006. The VHE {gamma}-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of the VHE {gamma}-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of {tau}{sup rise}{sub d} = (1.69 {+-} 0.30) days and {tau}{sup decay}{sub d} = (0.611 {+-} 0.080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales ({approx}day), peak fluxes ({Phi}{sub >0.35TeV} {approx_equal} (1-3) Multiplication-Sign 10{sup -11} photons cm{sup -2} s{sup -1}), and VHE spectra. VLBA radio observations of 43 GHz of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken {approx}3 days after the peak of the VHE {gamma}-ray emission reveal an enhanced flux from the core (flux increased by factor {approx}2; variability timescale <2 days). The long-term (2001-2010) multi-wavelength (MWL

  20. The 2010 Very High Energy Gamma-Ray Flare and 10 Years of Multi-Wavelength Observations of M87

    NASA Technical Reports Server (NTRS)

    Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; hide

    2011-01-01

    The giant radio galaxy M87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3-6) X 10(exp 9) Solar Mass) provides a unique opportunity to investigate the origin of very high energy (VHE; E>100 GeV) gamma-ray emission generated in relativistic outflows and the surroundings of super-massive black holes. M87 has been established as a VHE gamma -ray emitter since 2006. The VHE gamma -ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected. triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz VLBA). The excellent sampling of the VHE gamma-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of rise tau ((sup rise sub d) = (1:69 +/- 0:30) days and tau(sup decay sub d = (0:611 +/- 0:080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (approx day), peak fluxes (Phi (sub > 0:35 TeV) approx. equals (1 - 3) X 10(exp -11) ph / square cm/s), and VHE spectra. 43 GHz VLBA radio observations of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken approx 3 days after the peak of the VHE gamma -ray emission reveal an enhanced flux from the core (flux increased by factor approx 2; variability timescale < 2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M87, spanning from radio to VHE and including data from HST, LT, VLA and

  1. The Chandra Multi-wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-Ray-selected AGNs

    NASA Astrophysics Data System (ADS)

    Trichas, Markos; Green, Paul J.; Silverman, John D.; Aldcroft, Tom; Barkhouse, Wayne; Cameron, Robert A.; Constantin, Anca; Ellison, Sara L.; Foltz, Craig; Haggard, Daryl; Jannuzi, Buell T.; Kim, Dong-Woo; Marshall, Herman L.; Mossman, Amy; Pérez, Laura M.; Romero-Colmenero, Encarni; Ruiz, Angel; Smith, Malcolm G.; Smith, Paul S.; Torres, Guillermo; Wik, Daniel R.; Wilkes, Belinda J.; Wolfgang, Angie

    2012-06-01

    From optical spectroscopy of X-ray sources observed as part of the Chandra Multi-wavelength Project (ChaMP), we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow-up using the FLWO/1.5 m, SAAO/1.9 m, WIYN 3.5 m, CTIO/4 m, KPNO/4 m, Magellan/6.5 m, MMT/6.5 m, and Gemini/8 m telescopes, and from archival Sloan Digital Sky Survey (SDSS) spectroscopy. We classify the optical counterparts as 50% broad-line active galactic nuclei (AGNs), 16% emission line galaxies, 14% absorption line galaxies, and 20% stars. We detect QSOs out to z ~ 5.5 and galaxies out to z ~ 3. We have compiled extensive photometry, including X-ray (ChaMP), ultraviolet (GALEX), optical (SDSS and ChaMP-NOAO/MOSAIC follow-up), near-infrared (UKIDSS, Two Micron All Sky Survey, and ChaMP-CTIO/ISPI follow-up), mid-infrared (WISE), and radio (FIRST and NVSS) bands. Together with our spectroscopic information, this enables us to derive detailed spectral energy distributions (SEDs) for our extragalactic sources. We fit a variety of template SEDs to determine bolometric luminosities, and to constrain AGNs and starburst components where both are present. While ~58% of X-ray Seyferts (1042 erg s-1 < L 2 - 10 keV <1044 erg s-1) require a starburst event (>5% starburst contribution to bolometric luminosity) to fit observed photometry only 26% of the X-ray QSO (L 2 - 10 keV >1044 erg s-1) population appear to have some kind of star formation contribution. This is significantly lower than for the Seyferts, especially if we take into account torus contamination at z > 1 where the majority of our X-ray QSOs lie. In addition, we observe a rapid drop of the percentage of starburst contribution as X-ray luminosity increases. This is consistent with the quenching of star formation by powerful QSOs, as predicted by the merger model, or with a time lag between the peak of star formation and QSO activity. We have tested the hypothesis that there should be a

  2. Understanding the Connection Between Active Galactic Nuclei and Host Star Formation Through Multi-Wavelength Population Synthesis Modeling

    NASA Astrophysics Data System (ADS)

    Draper, Aden R.

    Supermassive black holes, black holes with masses ≳106M⊙ , are found at the centers of all massive galaxies. These massive black holes grew from smaller seed black holes through accretion events. Accreting black holes are very bright in the radio through very hard X-ray spectral regimes. Due to the location of these accreting black holes at the centers of galaxies, they are referred to as active galactic nuclei (AGN). It is understood that AGN are an important phase of galaxy evolution; however, the role of AGN in massive galaxy formation is very poorly constrained. Here, the unique tool of multi-wavelength population synthesis modeling is used to study the average properties of AGN and their host galaxies with a focus on host galaxy star formation and the role of black hole growth in galaxy evolution. Knowledge of the AGN population from deep X-ray surveys is combined with theoretical AGN spectral energy distributions to predict various observables of the AGN population in wavelength regions from the far infrared to very hard X-rays. Comparison of the model predictions to observations constrains the model input parameters and allows for the determination of average properties of the AGN population. Particular attention is paid to a special class of AGN known as Compton thick AGN. These AGN are deeply embedded in gas and dust such that the column density obscuring the line of sight to the central engine of the AGN exceeds 1/sigmaT ˜ 1024 cm -2, where sigmaT is the Thomson cross-section of the electron---a column density comparable to that of the human chest. Theoretical and simulational evidence suggest that these Compton thick AGN may be recently triggered, rapidly accreting AGN, making them of special interest to researchers. I found that Compton thick AGN are likely to contribute ˜20% of the peak of the cosmic X-ray background (XRB) at ˜30 keV and demonstrated that a significant portion of Compton thick AGN may be accreting very rapidly. Moreover, Compton

  3. The effect of Brown Carbon on thermal-optical analysis: a correction based on optical multi-wavelength analysis

    NASA Astrophysics Data System (ADS)

    Dario, Massabò; Lorenzo, Caponi; Chiara, Bove Maria; Paolo, Prati

    2016-04-01

    Carbonaceous aerosol (CA) has an important impact on air quality, human health and climate change. Total Carbon (TC) is generally divided in organic carbon (OC) and elemental carbon (EC) (although a minor fraction of carbonate carbon (CC) may be present). This classification is based on their thermo-optical properties: while EC is strongly light absorbing, OC is generally transparent in the visible range except for some particular compounds. In fact, another fraction of light-absorbing organic carbon exists which is not black and is generally called brown carbon (BrC) (Andreae and Gelencsér, 2006). We recently introduced a new method to apportion the absorption coefficient (babs) of carbonaceous atmospheric aerosols starting from multi-wavelength optical analysis (Massabò et al., 2015). This analysis is performed by the MWAA, an instrument developed at the Physics Department of University of Genoa (Massabò et al., 2013) able to measure the aerosol absorption coefficient at 5 different wavelengths ranging from UV to IR. The method is based on the information gathered at these five different wavelengths, in a renewed and upgraded version of the approach usually referred to as Aethalometer model (Sandradewi et al., 2008). The resulting optical apportionment provides the quantification of EC and, with some assumptions, also of OC coming from fossil fuels and wood burning. Thermal-optical methods are presently the most widespread approach to OC/EC speciation. Despite their popularity, there is still a disagreement among the results, especially for what concerns EC as different thermal protocols can be used. In fact, the pyrolysis occurring during the analysis can heavily affect OC/EC separation, depending on PM composition in addition to the used protocol. Furthermore, the presence in the sample of BrC can shift the split point since it is light absorbing also @ 635nm, the typical laser wavelength used in this technique (Chen et al., 2015). We present here the

  4. The 2010 Very High Energy γ-Ray Flare And 10 Years Of Multi-Wavelength Observations Of M 87

    DOE PAGES

    Abramowski, A.

    2012-02-02

    The giant radio galaxy M87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 - 6) X 109MΘ ) provides a unique opportunity to investigate the origin of very high energy (VHE; E>100 GeV) γ-ray emission generated in relativistic outflows and the surroundings of super-massive black holes. M87 has been established as a VHE γ-ray emitter since 2006. The VHE γ-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M87 by the MAGIC and VERITAS instruments in 2010 are reported. During themore » campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz VLBA). The excellent sampling of the VHE -ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of τrise d = (1:69 ± 0:30) days and τdecay d = (0:611 ± 0:080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (~day), peak fluxes (Φ>0:35 TeV ≃ (1 - 3) X 10-11 ph cm-2 s-1), and VHE spectra. 43 GHz VLBA radio observations of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken ~ 3 days after the peak of the VHE γ-ray emission reveal an enhanced flux from the core (flux increased by factor ~ 2; variability timescale < 2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M87, spanning from radio to VHE and including data from HST, LT, VLA and EVN, is used to further investigate the origin of the VHE γ-ray emission. No unique, common MWL

  5. The 2010 Very High Energy γ-Ray Flare and 10 Years of Multi-wavelength Observations of M 87

    NASA Astrophysics Data System (ADS)

    Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Clapson, A. C.; Coignet, G.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Häffner, S.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khangulyan, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Laffon, H.; Lamanna, G.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.; H.E.S.S. Collaboration; Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Braun, I.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido, D.; Giavitto, G.; Godinović, N.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Huber, B.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, M.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Munar, P.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thom, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Vankov, H.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; MAGIC Collaboration; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Cesarini, A.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dickherber, R.; Duke, C.; Errando, M.; Falcone, A.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Godambe, S.; Griffin, S.; Grube, J.; Gyuk, G.; Hanna, D.; Holder, J.; Huan, H.; Hui, C. M.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Maier, G.; McArthur, S.; McCann, A.; Moriarty, P.; Mukherjee, R.; Nuñez, P. D.; Ong, R. A.; Orr, M.; Otte, A. N.; Park, N.; Perkins, J. S.; Pichel, A.; Pohl, M.; Prokoph, H.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Ruppel, J.; Schroedter, M.; Sembroski, G. H.; Şentürk, G. D.; Telezhinsky, I.; Tešić, G.; Theiling, M.; Thibadeau, S.; Varlotta, A.; Vassiliev, V. V.; Vivier, M.; Wakely, S. P.; Weekes, T. C.; Williams, D. A.; Zitzer, B.; VERITAS Collaboration; Barres de Almeida, U.; Cara, M.; Casadio, C.; Cheung, C. C.; McConville, W.; Davies, F.; Doi, A.; Giovannini, G.; Giroletti, M.; Hada, K.; Hardee, P.; Harris, D. E.; Junor, W.; Kino, M.; Lee, N. P.; Ly, C.; Madrid, J.; Massaro, F.; Mundell, C. G.; Nagai, H.; Perlman, E. S.; Steele, I. A.; Walker, R. C.; Wood, D. L.

    2012-02-01

    The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 - 6) × 109 M ⊙) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) γ-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE γ-ray emitter since 2006. The VHE γ-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of the VHE γ-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of τrise d = (1.69 ± 0.30) days and τdecay d = (0.611 ± 0.080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (~day), peak fluxes (Φ>0.35 TeV ~= (1-3) × 10-11 photons cm-2 s-1), and VHE spectra. VLBA radio observations of 43 GHz of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken ~3 days after the peak of the VHE γ-ray emission reveal an enhanced flux from the core (flux increased by factor ~2; variability timescale <2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M 87, spanning from radio to VHE and including data from Hubble Space Telescope, Liverpool Telescope, Very Large Array, and European VLBI Network

  6. The 2010 Very High Energy γ-Ray Flare And 10 Years Of Multi-Wavelength Observations Of M 87

    SciTech Connect

    Abramowski, A.

    2012-02-02

    The giant radio galaxy M87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 - 6) X 109MΘ ) provides a unique opportunity to investigate the origin of very high energy (VHE; E>100 GeV) γ-ray emission generated in relativistic outflows and the surroundings of super-massive black holes. M87 has been established as a VHE γ-ray emitter since 2006. The VHE γ-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz VLBA). The excellent sampling of the VHE -ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of τrise d = (1:69 ± 0:30) days and τdecay d = (0:611 ± 0:080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (~day), peak fluxes (Φ>0:35 TeV ≃ (1 - 3) X 10-11 ph cm-2 s-1), and VHE spectra. 43 GHz VLBA radio observations of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken ~ 3 days after the peak of the VHE γ-ray emission reveal an enhanced flux from the core (flux increased by factor ~ 2; variability timescale < 2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M87, spanning from radio to VHE and including data from HST, LT, VLA and EVN, is used to further investigate the origin of the

  7. LED Update

    SciTech Connect

    Johnson, Mark L.; Gordon, Kelly L.

    2006-09-01

    This article, which will appear in RESIDENTIAL LIGHTING MAGAZINE, interviews PNNL's Kelly Gordon and presents the interview in question and answer format. The topic is a light emitting diode (LED) lighting also known as solid state lighting. Solid state lighting will be a new category in an energy efficient lighting fixture design competition called Lighting for Tomorrow sponsored by the US Department of Energy Emerging Technologies Office, the American Institute for Lighting, and the Consortium for Energy Efficiency. LED technology has been around since the ’60s, but it has been used mostly for indicator lights on electronics equipment. The big breakthrough was the development in the 1990s of blue LEDs which can be combined with the red and green LEDs that already existed to make white light. LEDs produce 25 to 40 lumens of light per watt of energy used, almost as much as a CFL (50 lumens per watt) and much more efficient than incandescent sources, which are around 15 lumens per watt. They are much longer lived and practical in harsh environments unsuitable for incandescent lighting. They are ready for niche applications now, like under-counter lighting and may be practical for additional applications as technological challenges are worked out and the technology is advancing in leaps and bounds.

  8. LED lamp

    SciTech Connect

    Galvez, Miguel; Grossman, Kenneth; Betts, David

    2013-11-12

    There is herein described a lamp for providing white light comprising a plurality of light sources positioned on a substrate. Each of said light sources comprises a blue light emitting diode (LED) and a dome that substantially covers said LED. A first portion of said blue light from said LEDs is transmitted through said domes and a second portion of said blue light is converted into a red light by a first phosphor contained in said domes. A cover is disposed over all of said light sources that transmits at least a portion of said red and blue light emitted by said light sources. The cover contains a second phosphor that emits a yellow light in response to said blue light. The red, blue and yellow light combining to form the white light and the white light having a color rendering index (CRI) of at least about 80.

  9. Switchable multi-wavelength fiber ring laser based on a compact in-fiber Mach-Zehnder interferometer with photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Chen, W. G.; Lou, S. Q.; Feng, S. C.; Wang, L. W.; Li, H. L.; Guo, T. Y.; Jian, S. S.

    2009-11-01

    Switchable multi-wavelength fiber ring laser with an in-fiber Mach-Zehnder interferometer incorporated into the ring cavity serving as wavelength-selective filter at room temperature is demonstrated. The filter is formed by splicing a section of few-mode photonic crystal fiber (PCF) and two segments of single mode fiber (SMF) with the air-holes on the both sides of PCF intentionally collapsed in the vicinity of the splices. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-, dual- and triple-wavelength lasing operations by exploiting polarization hole burning (PHB) effect.

  10. Switchable multi-wavelength erbium-doped fiber ring laser based on cascaded polarization maintaining fiber Bragg gratings in a Sagnac loop interferometer

    NASA Astrophysics Data System (ADS)

    Feng, Suchun; Xu, Ou; Lu, Shaohua; Ning, Tigang; Jian, Shuisheng

    2008-12-01

    A switchable multi-wavelength erbium-doped fiber (EDF) ring laser based on cascaded polarization maintaining fiber Bragg gratings (PMFBGs) in a Sagnac loop interferometer as the wavelength-selective filter at room temperature is proposed. Due to the polarization hole burning (PHB) enhanced by the PMFBGs, stable single-, dual-, three- and four-wavelength lasing operations can be obtained. The laser can be switched among the stable single-, dual-, three- and four-wavelength lasing operations by adjusting the polarization controllers (PCs). The optical signal-to-noise ratio (OSNR) is over 50 dB.

  11. Ultra-small near-infrared multi-wavelength light source using a heterojunction photonic crystal waveguide and self-assembled InAs quantum dots

    NASA Astrophysics Data System (ADS)

    Uchida, Sho; Ozaki, Nobuhiko; Nakahama, Teruyuki; Oda, Hisaya; Ikeda, Naoki; Sugimoto, Yoshimasa

    2017-05-01

    We herein propose and verify an ultra-small near-infrared (NIR) multi-wavelength light source using a heterojunction photonic crystal waveguide (PC-WG) and quantum dots (QDs). A heterojunction two-dimensional PC-WG, which consists of multiple PC-WGs with sequentially shifted structural parameters, is fabricated on a GaAs-slab including InAs QDs. Spontaneous emission (SE) from embedded InAs QDs was enhanced at multiple wavelengths resonating with slow-light regions of the PC-WG modes. The enhanced SE was propagated and detected through the heterojunction PC-WG. These results indicate the feasibility of the proposed light source.

  12. Dual-state dissipative solitons from an all-normal-dispersion erbium-doped fiber laser: continuous wavelength tuning and multi-wavelength emission.

    PubMed

    Wu, Zhichao; Fu, Songnian; Chen, Changxiu; Tang, Ming; Shum, Perry; Liu, Deming

    2015-06-15

    We propose and experimentally demonstrate switchable operation of dissipative solitons (DSs) in an erbium-doped fiber laser. By managing normal dispersion of laser cavity, the 3-dB spectral bandwidth up to 8.1 nm can be obtained with the help of a semiconductor saturable absorber mirror. Using an inline polarizer, the fiber laser can be separately operated at either wavelength-tunable or multi-wavelength emission. The central wavelength of DS can be continuously tuned from 1554 to 1561 nm with its spectra maintaining standard rectangular shape. Alternatively, triple-wavelength DSs at 1535, 1544, and 1553 nm can be simultaneously obtained.

  13. Multi-wavelength emission through self-induced second-order wave-mixing processes from a Nd3+ doped crystalline powder random laser

    NASA Astrophysics Data System (ADS)

    Moura, André L.; Jerez, Vladimir; Maia, Lauro J. Q.; Gomes, Anderson S. L.; de Araújo, Cid B.

    2015-09-01

    Random lasers (RLs) based on neodymium ions (Nd3+) doped crystalline powders rely on multiple light scattering to sustain laser oscillation. Although Stokes and anti-Stokes Nd3+ RLs have been demonstrated, the optical gain obtained up to now was possibly not large enough to produce self-frequency conversion. Here we demonstrate self-frequency upconversion from Nd3+ doped YAl3(BO3)4 monocrystals excited at 806 nm, in resonance with the Nd3+ transition 4I9/2 → 4F5/2. Besides the observation of the RL emission at 1062 nm, self-converted second-harmonic at 531 nm, and self-sum-frequency generated emission at 459 nm due to the RL and the excitation laser at 806 nm, are reported. Additionally, second-harmonic of the excitation laser at 403 nm was generated. These results exemplify the first multi-wavelength source of radiation owing to nonlinear optical effect in a Nd3+ doped crystalline powder RL. Contrary to the RLs based on dyes, this multi-wavelength light source can be used in photonic devices due to the large durability of the gain medium.

  14. Monitoring quality consistency of Liuwei Dihuang Pill by integrating the ultraviolet spectroscopic fingerprint, a multi-wavelength fusion fingerprint method, and antioxidant activities.

    PubMed

    Yan, Bo; Sun, Guoxiang

    2017-08-24

    Liuwei Dihuang Pill, a classical traditional Chinese medicine, has been widely used to treat kidney yin deficiency in China for hundreds of years. Little attention, however, has been paid to quality control methods for this formulation. In the present study, we aimed to establish a comprehensive and practical quality evaluation system for Liuwei Dihuang Pill. Thus, ultraviolet spectroscopic fingerprints and multi-wavelength fusion fingerprints have been proposed for quality consistency evaluation of the popular patent. The similarity analysis of Liuwei Dihuang Pill samples was evaluated by systematic quantitative fingerprint method from qualitative and quantitative perspectives. The results showed that 26 batches of samples were classified into five grades for fusion fingerprints and three grades for ultraviolet spectroscopic fingerprints. Moreover, the fingerprint-efficacy correlation was also established and confirmed through the partial least squares model to visualize the antioxidant activity of Liuwei Dihuang Pill in vitro. In conclusion, these results indicated that integrating ultraviolet spectroscopic fingerprints and multi-wavelength fusion fingerprints coupled with antioxidant activities provide a rapid and effective approach to monitor the quality consistency of Liuwei Dihuang Pill. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Multi-wavelength emission through self-induced second-order wave-mixing processes from a Nd3+ doped crystalline powder random laser

    PubMed Central

    Moura, André L.; Jerez, Vladimir; Maia, Lauro J. Q.; Gomes, Anderson S. L.; de Araújo, Cid B.

    2015-01-01

    Random lasers (RLs) based on neodymium ions (Nd3+) doped crystalline powders rely on multiple light scattering to sustain laser oscillation. Although Stokes and anti-Stokes Nd3+ RLs have been demonstrated, the optical gain obtained up to now was possibly not large enough to produce self-frequency conversion. Here we demonstrate self-frequency upconversion from Nd3+ doped YAl3(BO3)4 monocrystals excited at 806 nm, in resonance with the Nd3+ transition 4I9/2 → 4F5/2. Besides the observation of the RL emission at 1062 nm, self-converted second-harmonic at 531 nm, and self-sum-frequency generated emission at 459 nm due to the RL and the excitation laser at 806 nm, are reported. Additionally, second-harmonic of the excitation laser at 403 nm was generated. These results exemplify the first multi-wavelength source of radiation owing to nonlinear optical effect in a Nd3+ doped crystalline powder RL. Contrary to the RLs based on dyes, this multi-wavelength light source can be used in photonic devices due to the large durability of the gain medium. PMID:26334517

  16. All-fiber multi-wavelength passive Q-switched Er/Yb fiber laser based on a Tm-doped fiber saturable absorber

    NASA Astrophysics Data System (ADS)

    Posada-Ramírez, B.; Durán-Sánchez, M.; Álvarez-Tamayo, R. I.; Alaniz-Baylón, J.; Ibarra-Escamilla, B.; López-Estopier, R.; Kuzin, E. A.

    2017-03-01

    We report on a ring cavity, multi-wavelength, passive Q-switched erbium–ytterbium double cladding fiber laser based on the use of an unpumped segment of Tm-doped fiber acting as a saturable absorber for passive Q-switched pulse generation and a wavelength filter for multi-wavelength laser generation. By performing pump power variations from 1.6 to 9.8 W, stable Q-switched laser pulses are observed in a repetition rate from 135.8 to 27.5 kHz at room temperature. With a maximal repetition rate of 135.8 kHz, the minimum pulse duration of 430 ns is obtained. The maximal average output power of 2.2 W is reached with a pump power of 9.8 W. The maximum pulse energy was 16.4 µJ and the average output power slope efficiency is ~24.8%. The obtained results demonstrate a laser performance with extended range of high repetition rate and improved stability.

  17. General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films

    PubMed Central

    Kim, Tae Young; Badsha, Md. Alamgir; Yoon, Junho; Lee, Seon Young; Jun, Young Chul; Hwangbo, Chang Kwon

    2016-01-01

    We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devices. PMID:26965195

  18. General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films

    NASA Astrophysics Data System (ADS)

    Kim, Tae Young; Badsha, Md. Alamgir; Yoon, Junho; Lee, Seon Young; Jun, Young Chul; Hwangbo, Chang Kwon

    2016-03-01

    We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devices.

  19. Integral Field Spectroscopy and multi-wavelength imaging of nearby spiral galaxies: NGC 5668 as a pilot case for MEGARA

    NASA Astrophysics Data System (ADS)

    Marino, R. A.; Gil de Paz, A.; Castillo-Morales, A.; Muñoz-Mateos, J. C.; Sánchez, S. F.; Pérez-González, P. G.; Zamorano, J.; Gallego, J.; Alonso-Herrero, A.; Kannappan, S.; Boissier, S.; Eliche-Moral, M. C.; García-Vargas, M. L.; Carrasco, E.; Vílchez, J. M.; Sánchez-Moreno, F. M.

    2013-05-01

    MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4 m telescope in La Palma. MEGARA will be a 3rd generation instrument for GTC. It is led by the University Complutense of Madrid with the collaboration of INAOE, IAA, UPM and comprises more than 50 researchers from a large number of institutions worldwide.

  20. Development of a multi-wavelength diffuse optical tomography system for early diagnosis of rheumatoid arthritis: simulation, phantoms and healthy human studies

    PubMed Central

    Wu, Hao Yang; Filer, Andrew; Styles, Iain; Dehghani, Hamid

    2016-01-01

    A multi-wavelength diffuse optical tomography (DOT) system has been developed to directly extract physiological information, such as total haemoglobin concentration, from tissue in human hand joints. Novel methods for 3D surface imaging and spectrally constrained image reconstruction are introduced and their potential application to imaging of rheumatoid arthritis is discussed. Results are presented from simulation studies as well as experiments using phantoms and data from imaging of three healthy volunteers. The image features are recovered partially for phantom data using transmission measurements only. Images that reveal joint regions and surrounding features within the hand are shown to co-register with co–acquired ultrasound images which are shown to be related to total haemoglobin concentration. PMID:27896015

  1. A BOINC based, citizen-science project for pixel spectral energy distribution fitting of resolved galaxies in multi-wavelength surveys

    NASA Astrophysics Data System (ADS)

    Vinsen, Kevin; Thilker, David

    2013-11-01

    In this work we present our experience from the first year of theSkyNet Pan-STARRS1 Optical Galaxy Survey (POGS) project. This citizen-scientist driven research project uses the Berkeley Open Infrastructure for Network Computing (BOINC) middleware and thousands of Internet-connected computers to measure the resolved galactic structural properties of ˜100,000 low redshift galaxies. We are combining the spectral coverage of GALEX, Pan-STARRS1, SDSS, and WISE to generate a value-added, multi-wavelength UV-optical-NIR galaxy atlas for the nearby Universe. Specifically, we are measuring physical parameters (such as local stellar mass, star formation rate, and first-order star formation history) on a resolved pixel-by-pixel basis using spectral energy distribution (SED) fitting techniques in a distributed computing mode. Berkeley Open Infrastructure for Network Computing.

  2. Airborne measurements of multi-wavelength aerosol optical depth and cloud-transmitted radiances in the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES)

    NASA Astrophysics Data System (ADS)

    Shinozuka, Y.; Johnson, R. R.; LeBlanc, S. E.; Chang, C. S.; Redemann, J.

    2016-12-01

    We report on our recent airborne measurements of multi-wavelength aerosol optical depth and cloud-transmitted radiances over the North Atlantic. We ran the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) in November 2015 and the 14-channel Ames Airborne Tracking Sunphotometer (AATS-14) in May and June 2016, both aboard the NASA C-130 aircraft. These sunphotometers provide measurements of overlying cirrus and aerosol optical depths of up to about 0.5 and constrain ecosystem and aerosol retrievals from the accompanying nadir-viewing remote sensing instruments. In addition, 4STAR measures hyperspectral transmitted light, which enables the retrieval of cloud optical depth, effective radius, and thermodynamic phase from below cloud. Our measurements contribute to the science objectives of the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES), an interdisciplinary investigation resolving key processes controlling marine ecosystems and aerosols that are essential to our understanding of Earth system function and future change.

  3. A multi-wavelength streak-optical-pyrometer for warm-dense matter experiments at NDCX-I and NDCX-II

    NASA Astrophysics Data System (ADS)

    Ni, P. A.; Bieniosek, F. M.; Henestroza, E.; Lidia, S. M.

    2014-01-01

    We report on a multi-wavelength streak-optical-pyrometer (SOP) developed the for warm-dense-matter (WDM) experiments at the existing NDCX-I facility and the NDCX-II facility currently being commissioned at LBNL. The SOP served as the primary temperature diagnostic in the recent NDCX-I experiments, in which an intense K+ beam was used to heat different metal samples into WDM states. The SOP consists of a spectral grating (visible and near-infrared spectral range) and a fast, high-dynamic-range optical streak camera. The instrument is calibrated absolutely with a NIST-traceable tungsten ribbon lamp and can itself be considered as an absolutely calibrated, time-resolving spectrometer. The sample temperature is determined from fitting the recorded thermal spectrum into the Planck formula multiplied by a model of emissivity.

  4. THE BRIGHTEST GAMMA-RAY FLARING BLAZAR IN THE SKY: AGILE AND MULTI-WAVELENGTH OBSERVATIONS OF 3C 454.3 DURING 2010 NOVEMBER

    SciTech Connect

    Vercellone, S.; Romano, P.; Vittorini, V.; Donnarumma, I.; Pacciani, L.; Fiocchi, M.; Bazzano, A.; Ubertini, P.; Raiteri, C. M.; Villata, M.; Bianchin, V.; Bulgarelli, A.; Maraschi, L.; Pian, E.; Chen, A. W.

    2011-08-01

    Since 2005, the blazar 3C 454.3 has shown remarkable flaring activity at all frequencies, and during the last four years it has exhibited more than one {gamma}-ray flare per year, becoming the most active {gamma}-ray blazar in the sky. We present for the first time the multi-wavelength AGILE, Swift, INTEGRAL, and GASP-WEBT data collected in order to explain the extraordinary {gamma}-ray flare of 3C 454.3 which occurred in 2010 November. On 2010 November 20 (MJD 55520), 3C 454.3 reached a peak flux (E >100 MeV) of F{sup p}{sub {gamma}} = (6.8 {+-} 1.0) x 10{sup -5} photons cm{sup -2} s{sup -1} on a timescale of about 12 hr, more than a factor of six higher than the flux of the brightest steady {gamma}-ray source, the Vela pulsar, and more than a factor of three brighter than its previous super-flare on 2009 December 2-3. The multi-wavelength data make possible a thorough study of the present event: the comparison with the previous outbursts indicates a close similarity to the one that occurred in 2009. By comparing the broadband emission before, during, and after the {gamma}-ray flare, we find that the radio, optical, and X-ray emission varies within a factor of 2-3, whereas the {gamma}-ray flux by a factor of 10. This remarkable behavior is modeled by an external Compton component driven by a substantial local enhancement of soft seed photons.

  5. MULTI-WAVELENGTH OBSERVATIONS OF SUPERNOVA 2011ei: TIME-DEPENDENT CLASSIFICATION OF TYPE IIb AND Ib SUPERNOVAE AND IMPLICATIONS FOR THEIR PROGENITORS

    SciTech Connect

    Milisavljevic, Dan; Margutti, Raffaella; Soderberg, Alicia M.; Chomiuk, Laura; Sanders, Nathan E.; Pignata, Giuliano; Bufano, Filomena; Fesen, Robert A.; Parrent, Jerod T.; Parker, Stuart; Mazzali, Paolo; Pian, Elena; Pickering, Timothy; Buckley, David A. H.; Crawford, Steven M.; Gulbis, Amanda A. S.; Hettlage, Christian; Hooper, Eric; Nordsieck, Kenneth H.; O'Donoghue, Darragh; and others

    2013-04-10

    We present X-ray, UV/optical, and radio observations of the stripped-envelope, core-collapse supernova (SN) 2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within {approx}1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogen Balmer profiles that subside rapidly and are replaced by Type Ib-like He-rich features on a timescale of one week. High-cadence monitoring of this transition suggests absorption attributable to a high-velocity ({approx}> 12, 000 km s{sup -1}) H-rich shell, which is likely present in many Type Ib events. Radio observations imply a shock velocity of v Almost-Equal-To 0.13 c and a progenitor star average mass-loss rate of M-dot {approx}1.4 Multiplication-Sign 10{sup -5} M{sub sun} yr{sup -1} (assuming wind velocity v{sub w} = 10{sup 3} km s{sup -1}). This is consistent with independent constraints from deep X-ray observations with Swift-XRT and Chandra. Overall, the multi-wavelength properties of SN 2011ei are consistent with the explosion of a lower-mass (3-4 M{sub Sun }), compact (R{sub *} {approx}< 1 Multiplication-Sign 10{sup 11} cm), He-core star. The star retained a thin hydrogen envelope at the time of explosion, and was embedded in an inhomogeneous circumstellar wind suggestive of modest episodic mass loss. We conclude that SN 2011ei's rapid spectral metamorphosis is indicative of time-dependent classifications that bias estimates of the relative explosion rates for Type IIb and Ib objects, and that important information about a progenitor star's evolutionary state and mass loss immediately prior to SN explosion can be inferred from timely multi-wavelength observations.

  6. The ICRF-3: Status, Plans, and Multi-wavelength Progress on the next generation Celestial Reference Frame.

    NASA Astrophysics Data System (ADS)

    Jacobs, Christopher

    2015-08-01

    ICRF-3 seeks to improve upon the highly successful ICRF-2. Our goals are to improve the precision, spatial and frequency coverage relative to the ICRF-2 by 2018. This date is driven by the desire to create radio frames that are ready for comparison with the Gaia optical frame.Several specific actions are underway. A collaboration to improve at S/X-band precision of the Very Long Baseline Array (VLBA) Calibrator Survey's ~2200 sources, which are typically 5 times less precise than the rest of the ICRF-2, is bearing fruit and is projected to yield a factor of 3 improvement in precision. S/X-band southern hemisphere precision improvements are underway with observations using southern antennas such as the AuScope, Warkworth, and HartRAO, South Africa.We also seek to improve radio frequency coverage with X/Ka-band and K-band work. An X/Ka frame of 660 sources now has full sky coverage from the addition of a 2nd southern station in Argentina which is strengthening the southern hemisphere in general. The X/Ka-band frame's precision is now comparable to the ICRF-2 for the 530 sources in common. A K-band collaboration has formed with similar coverage and southern precision goals. By the time of this meeting, we expect K-band to complete full sky coverage with south polar cap observations and to improve spatial density north of -30 deg declination with VLBA observations.On the analysis front, special attention is being given to combination techniques both of Very Long Baseline Interferometry (VLBI) frames and of multiple data types. Consistency of the Celestial Reference Frame (CRF) with the Terrestrial Reference Frame (TRF) and Earth Oreintation Parameters (EOP) is another area of concern. Comparison of celestial frame solutions from various groups is underway in order to identify and correct systematic errors. We will discuss evidence emerging for 100 µas zonal errors in the ICRF2 in the declination range from 0 to -30 deg.Finally, work is underway to identify and

  7. GRB 130427A and SN 2013cq: A Multi-wavelength Analysis of An Induced Gravitational Collapse Event

    NASA Astrophysics Data System (ADS)

    Ruffini, R.; Wang, Y.; Enderli, M.; Muccino, M.; Kovacevic, M.; Bianco, C. L.; Penacchioni, A. V.; Pisani, G. B.; Rueda, J. A.

    2015-01-01

    We performed a data analysis of the observations by the Swift, NuStar, and Fermi satellites in order to probe the induced gravitational collapse (IGC) paradigm for gamma-ray bursts (GRBs) associated with supernovae (SNe) in the terra incognita of GRB 130427A. We compare our data analysis with those in the literature. We have verified that GRB 130427A conforms to the IGC paradigm by examining the power law behavior of the luminosity in the early 104 s of the XRT observations. This has led to the identification of the four different episodes of the binary driven hypernovae (BdHNe) and to the prediction, on 2013 May 2, of the occurrence of SN 2013cq, which was also observed in the optical band on 2013 May 13. The exceptional quality of the data has allowed the identification of novel features in Episode 3 including: (1) the confirmation and the extension of the existence of the recently discovered nested structure in the late X-ray luminosity in GRB 130427A, as well as the identification of a spiky structure at 102 s in the cosmological rest-frame of the source; (2) a power law emission of the GeV luminosity light curve and its onset at the end of Episode 2; and (3) different Lorentz Γ factors for the emitting regions of the X-ray and GeV emissions in this Episode 3. These results make it possible to test the details of the physical and astrophysical regimes at work in the BdHNe: (1) a newly born neutron star and the supernova ejecta, originating in Episode 1; (2) a newly formed black hole originating in Episode 2; and (3) the possible interaction among these components, observable in the standard features of Episode 3.

  8. GRB 130427A AND SN 2013cq: A MULTI-WAVELENGTH ANALYSIS OF AN INDUCED GRAVITATIONAL COLLAPSE EVENT

    SciTech Connect

    Ruffini, R.; Wang, Y.; Enderli, M.; Muccino, M.; Kovacevic, M.; Bianco, C. L.; Pisani, G. B.; Rueda, J. A.; Penacchioni, A. V.

    2015-01-01

    We performed a data analysis of the observations by the Swift, NuStar, and Fermi satellites in order to probe the induced gravitational collapse (IGC) paradigm for gamma-ray bursts (GRBs) associated with supernovae (SNe) in the terra incognita of GRB 130427A. We compare our data analysis with those in the literature. We have verified that GRB 130427A conforms to the IGC paradigm by examining the power law behavior of the luminosity in the early 10{sup 4} s of the XRT observations. This has led to the identification of the four different episodes of the binary driven hypernovae (BdHNe) and to the prediction, on 2013 May 2, of the occurrence of SN 2013cq, which was also observed in the optical band on 2013 May 13. The exceptional quality of the data has allowed the identification of novel features in Episode 3 including: (1) the confirmation and the extension of the existence of the recently discovered nested structure in the late X-ray luminosity in GRB 130427A, as well as the identification of a spiky structure at 10{sup 2} s in the cosmological rest-frame of the source; (2) a power law emission of the GeV luminosity light curve and its onset at the end of Episode 2; and (3) different Lorentz Γ factors for the emitting regions of the X-ray and GeV emissions in this Episode 3. These results make it possible to test the details of the physical and astrophysical regimes at work in the BdHNe: (1) a newly born neutron star and the supernova ejecta, originating in Episode 1; (2) a newly formed black hole originating in Episode 2; and (3) the possible interaction among these components, observable in the standard features of Episode 3.

  9. Multi-Wavelength Observation Results of the C5.6 Limb Flare of 1 August 2003

    NASA Astrophysics Data System (ADS)

    Li, Hui; You, Jianqi; Du, Qiusheng; Yu, Xingfeng

    2004-11-01

    We obtained a complete set of Hα, Ca Π 8542 Å and He I 10830 Å spectra and slit-jaw Hα images of the C5.6 limb flare of 1 August 2003 using the Multi-channel Infrared Solar Spectrograph (MISS) at Purple Mountain Observatory. This flare was also observed by the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) and partially by the Extreme-ultraviolet Imaging Telescope (EIT) on SOHO. This flare underwent a rapid rising and expanding episode in the impulsive phase. All the Hα, Ca Π 8542 Å and He I 10830 Å profiles of the flare are rather wide and the widest profiles were observed in the middle bright part of the flare instead of at the flare loop top near the flare maximum. The flare manifested obvious rotation in the flare loop and the decrease of the rotation angular speed with time at the loop-top may imply a de-twisting process of the magnetic field. The significant increases of the Doppler widths of these lines in the impulsive phase reflect quick heating of the chromosphere, and rapid rising and expanding of the flare loop. The RHESSI observations give a thermal energy spectrum for this flare, and two thermal sources and no non-thermal source are found in the reconstructed RHESSI images. This presumably indicates that the energy transfer in this flare is mainly by heat conduction. The stronger thermal source is located near the solar limb with its position unchanged in the flare process and spatially coincident with the intense EUV and Hα emissions. The weaker one moved during the flare process and is located in the Hα dark cavities. This flare may support the theory of the magnetic reconnections in the lower solar atmosphere.

  10. The circumstellar disk of HH 30. Searching for signs of disk evolution with multi-wavelength modeling

    NASA Astrophysics Data System (ADS)

    Madlener, D.; Wolf, S.; Dutrey, A.; Guilloteau, S.

    2012-07-01

    Context. Circumstellar disks are characteristic for star formation and vanish during the first few Myr of stellar evolution. During this time planets are believed to form in the dense midplane by growth, sedimentation and aggregation of dust. Indicators of disk evolution, such as holes and gaps, can be traced in the spectral energy distribution (SED) and spatially resolved images. Aims: We aim to construct a self-consistent model of HH 30 by fitting all available continuum observations simultaneously. New data sets not available in previous studies, such as high-resolution interferometric imaging with the Plateau de Bure Interferometer (PdBI) at λ = 1.3 mm and SED measured with IRS on the Spitzer Space Telescope in the mid-infrared, put strong constraints on predictions and are likely to provide new insights into the evolutionary state of this object. Methods: A parameter study based on simulated annealing was performed to find unbiased best-fit models for independent observations made in the wavelength domain λ ~ 1 μm...4 mm. The method essentially creates a Markov chain through parameter space by comparing predictions generated by our self-consistent continuum radiation transfer code MC3D with observations. Results: We present models of the edge-on circumstellar disk of HH 30 based on observations from the near-infrared to mm-wavelengths that suggest the presence of an inner depletion zone with ~45 AU radius and a steep decline of mm opacity beyond ≳ 140 AU. Our modeling indicates that several modes of dust evolution such as growth, settling, and radial migration are taking place in this object. Conclusions: High-resolution observations of HH 30 at different wavelengths with next-generation observatories such as ALMA and JWST will enable the modeling of inhomogeneous dust properties and significantly expand our understanding of circumstellar disk evolution.

  11. The Chandra Multi-Wavelength Project (ChaMP): A Serendipitous X-Ray Survey Using Chandra Archival Data

    NASA Technical Reports Server (NTRS)

    Wilkes, Belinda; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    The launch of the Chandra X-ray Observatory in July 2000 opened a new era in X-ray astronomy. Its unprecedented, < 1" spatial resolution and low background is providing views of the X-ray sky 10-100 times fainter than previously possible. We have begun to carry out a serendipitous survey of the X-ray sky using Chandra archival data to flux limits covering the range between those reached by current satellites and those of the small area Chandra deep surveys. We estimate the survey will cover about 8 sq.deg. per year to X-ray fluxes (2-10 keV) in the range 10(exp -13) - 6(exp -16) erg cm2/s and include about 3000 sources per year, roughly two thirds of which are expected to be active galactic nuclei (AGN). Optical imaging of the ChaMP fields is underway at NOAO and SAO telescopes using g',r',z' colors with which we will be able to classify the X-ray sources into object types and, in some cases, estimate their redshifts. We are also planning to obtain optical spectroscopy of a well-defined subset to allow confirmation of classification and redshift determination. All X-ray and optical results and supporting optical data will be place in the ChaMP archive within a year of the completion of our data analysis. Over the five years of Chandra operations, ChaMP will provide both a major resource for Chandra observers and a key research tool for the study of the cosmic X-ray background and the individual source populations which comprise it. ChaMP promises profoundly new science return on a number of key questions at the current frontier of many areas of astronomy including solving the spectral paradox by resolving the CXRB, locating and studying high redshift clusters and so constraining cosmological parameters, defining the true, possibly absorbed, population of quasars and studying coronal emission from late-type stars as their cores become fully convective. The current status and initial results from the ChaMP will be presented.

  12. Dissertation Talk: High Resolution Observations of Multi-Wavelength Emissions During Two X-Class White-Light Flares

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Cao, W.; Liu, C.; Yang, G.; Jing, J.; Denker, C.; Wang, H.

    2005-05-01

    We observed two X-class white-light flares (WLF) on 2003 October~29 (~20:40~UT) and November~2 (~17:16 UT) using the Dunn Solar Telescope (DST) and its High-Order Adaptive Optics (HOAO) system in several wavelengths. The spatial resolution was close to the diffraction limit of DST's 76~cm aperture. The temporal resolution was as high as 2~s. It is the first time that WLFs were observed in the Near Infrared (NIR) wavelength region. We present a detailed study in this presentation by comparing the photospheric continuum observations during these two events with corresponding line-of-sight (LOS) magnetograms of the Michelson Doppler Imager (MDI) and hard X-ray (HXR) data of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Our observations show that: Significant intensity enhancements were observed in the visible and NIR continua and G-band during the impulsive phase of the flares. The maximum intensity enhancements were 37% of white-light and 25% of the NIR continuum during the first event, and 76% of white-light and 66% of the NIR continuum for the second flare. The flares were typical two ribbon flares. All ribbons showed a brighter core surrounded by a halo structure. The ribbon separation speeds were about 28~km/s in the first and 24~km/s in the second event based on NIR observations. The derived electric fields in the reconnection current sheet Ec are about 23~V~ cm-1 and 22~V~cm-1, respectively. The NIR emission and the impulsive HXR emission up to 800~keV were well correlated, not considering a small delay of less than two minutes. The high resolution and high cadence images gave us the first chance to measure the cooling time of flares close to the photosphere. We found that the cooling process could be characterized by two steps. A quick temperature drop, which is related to the cooling process of the bright cores, and a relative slow decay related to the halo structures. The fine scale is in the order of less than 30~s and a few minutes for these

  13. A Multi-Wavelength Grain-by-Grain Survey of Lunar Soils in Search of Rare Materials

    NASA Astrophysics Data System (ADS)

    Crites, S.; Lucey, P. G.; Viti, T.

    2014-12-01

    The Moon is unique among terrestrial planets for its lack of an atmosphere and global tectonic or volcanic processes. These factors and its position in the inner solar system mean that it is a potential repository of meteoritic material from all of the terrestrial planets. The National Research Council's 2007 report on the Scientific Context for the Exploration of the Moon highlighted this unique possibility and defined the search for rare materials including those from the early Earth as a key goal for future lunar exploration. Armstrong et al. (2002) estimated that Earth material could be present at the 7 ppm level in surface lunar regolith and emphasized that since a single gram of lunar fines contains over 10 million particles, the search for terran material in lunar soils should begin with the current stock of lunar samples. Joy et al. (2012) demonstrated that mineral and lithologic relics of impactors can survive and be recognized in lunar samples, and recent work by Burchell et al. (2014) suggests that fossil fragments from Earth could survive the extreme shocks associated with transport to the Moon. Following the concept laid out by Armstrong et al. (2002), we are conducting a survey of lunar soil samples using microscopic hyperspectral imaging spectroscopy across visible, near-infrared, and thermal infrared wavelengths to conduct a search for rare particles, including those that could be sourced from the early Earth. Our system currently consists of three microscopic imaging spectrometers with ~30 micron spatial resolution, permitting resolved imaging of individual grains. Fields of view of at least 1 cm and scan rates near 1 mm/sec permit rapid processing of relatively large quantities of sample. Existing spectrometers cover the 0.5 to 2.5 micron region, permitting detection and characterization of the common iron-bearing lunar minerals olivine and pyroxene, and the 8-14 micron region, which permits detection of other, rarer minerals of interest such as

  14. Cluster membership probabilities from proper motions and multi-wavelength photometric catalogues. I. Method and application to the Pleiades cluster

    NASA Astrophysics Data System (ADS)

    Sarro, L. M.; Bouy, H.; Berihuete, A.; Bertin, E.; Moraux, E.; Bouvier, J.; Cuillandre, J.-C.; Barrado, D.; Solano, E.

    2014-03-01

    Context. With the advent of deep wide surveys, large photometric and astrometric catalogues of literally all nearby clusters and associations have been produced. The unprecedented accuracy and sensitivity of these data sets and their broad spatial, temporal and wavelength coverage make obsolete the classical membership selection methods that were based on a handful of colours and luminosities. We present a new technique designed to take full advantage of the high dimensionality (photometric, astrometric, temporal) of such a survey to derive self-consistent and robust membership probabilities of the Pleiades cluster. Aims: We aim at developing a methodology to infer membership probabilities to the Pleiades cluster from the DANCe multidimensional astro-photometric data set in a consistent way throughout the entire derivation. The determination of the membership probabilities has to be applicable to censored data and must incorporate the measurement uncertainties into the inference procedure. Methods: We use Bayes' theorem and a curvilinear forward model for the likelihood of the measurements of cluster members in the colour-magnitude space, to infer posterior membership probabilities. The distribution of the cluster members proper motions and the distribution of contaminants in the full multidimensional astro-photometric space is modelled with a mixture-of-Gaussians likelihood. Results: We analyse several representation spaces composed of the proper motions plus a subset of the available magnitudes and colour indices. We select two prominent representation spaces composed of variables selected using feature relevance determination techniques based in Random Forests, and analyse the resulting samples of high probability candidates. We consistently find lists of high probability (p > 0.9975) candidates with ≈1000 sources, 4 to 5 times more than obtained in the most recent astro-photometric studies of the cluster. Conclusions: Multidimensional data sets require

  15. Investigation of the spectral responses of laser generated aerosol from household coals using a state-of-the-art multi-wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Ajtai, Tibor; Utry, Noemi; Pinter, Mate; Kiss-Albert, Gergely; Smausz, Tomi; Konya, Zoltan; Hopp, Bela; Szabo, Gabor; Bozoki, Zoltan

    2016-04-01

    We present the investigation of the inherent, spectral features of laser generated and chemically characterized residential coal aerosols generated in our recently introduced laser ablation based LAC generator. The optical absorption and the scattering features of the generated aerosol were investigated by our state-of-the-art multi wavelength PAS instrument (4λ-PAS) and a multi wavelength cosinus sensor (Aurora 3000). The quantified wavelength dependency (AAE and SAE) are deduced from the measured data. Finally, relationship between the optical and the thermochemical characteristics is revealed. Atmospheric light absorbing carbonaceous particulate matter (LAC) is in the middle of scientific interest especially because of its climatic and adverse health relevance. The latest scientific assessments identified atmospheric soot as the second most important anthropogenic emission regarding its climatic effect and as one of the most harmful atmospheric constituents based on its health aspects. LAC dominantly originates from anthropogenic sources, so its real time and selective identification is also essential for the means of its legal regulation. Despite of its significance the inherent properties of LAC are rarely described and the available data is widely spread even in the case of the most intensively studied black or elementary carbon. Therefore, the investigation of the inherent climate and health relevant properties of atmospheric soot is a highly actual issue. Moreover investigation of the optical and toxic properties of LAC originating from the combustion of household coals is almost completely missing from literature. There are two major reasons for that. Firstly, the characteristic parameters of soot are complex and vary in a wide range and depend not only on the initial burning conditions and the type of fuels but also the ambient factors. The other is the lack of a soot standard material and a generator which are suitable for modelling the real atmospheric

  16. Spectral characterisation of mineralogical components of dust, HULIS and winter time aerosol using multi-wavelength photoacoustic spectrometer. A laboratory and a field study

    NASA Astrophysics Data System (ADS)

    Ajtai, Tibor; Utry, Noémi; Filep, Ágnes; Tátrai, Dávid; Bozóki, Zoltán; Szabó, Gábor

    2013-04-01

    Aerosol can interact with solar radiation via scattering and absorption. The back scattering fraction of incoming solar irradiation has cooling effect, while the forward scattering redistributes electromagnetic energy into the atmosphere. The photon energy transformed into thermal energy via the light absorption, therefore the absorption process heating absorbing particles and also their surroundings While scattering can be measured fairly accurately, the assessment of the radiative effect of light absorption by aerosol can only be determined with limited accuracy, in part, because of the lack of reliable instrument for absorption measurement. The photoacoustic (PA) spectroscopy is the only method that can measure light absorption by aerosol in-situ (without sampling artifacts) with high sensitivity and temporal resolution, but not widespread in its application yet. Recently, multi-wavelength photoacoustic instruments including excitation at UVs have become available and open up a new perspective on in-situ investigation of light absorption by aerosol as well as its wavelength dependency. In this study we present novel results of an in-situ study of aerosol light absorption measurement of re-dispersed mineralogical composition of dust such as illit, caolinite, quartz, rutile, limestone, hematite and HULIS aerosols using state-of-the-art multi-wavelength photoacoustic instrument (4λ-PAS). We experimentally demonstrated that the absorption feature of MAC (mass specific aerosol absorption) could be used as chemically selective parameter. We also demonstrated the results of an in-situ winter time ambient aerosol measurement. The hourly concentration of trace elements(i.e. K, Ca, Fe, and Si), gaseous pollutants (CO and NOx), as well as the size distribution of ambient aerosol were also analyzed during the measurement campaign. The levoglucosan measurement was made to confirm that the daily fluctuation of ambient AAE (absorption Angstrom Exponent) governed by the

  17. Optical and microphysical characterization of aerosol layers over South Africa by means of multi-wavelength depolarization and Raman lidar measurements

    NASA Astrophysics Data System (ADS)

    Giannakaki, Elina; van Zyl, Pieter G.; Müller, Detlef; Balis, Dimitris; Komppula, Mika

    2016-07-01

    Optical and microphysical properties of different aerosol types over South Africa measured with a multi-wavelength polarization Raman lidar are presented. This study could assist in bridging existing gaps relating to aerosol properties over South Africa, since limited long-term data of this type are available for this region. The observations were performed under the framework of the EUCAARI campaign in Elandsfontein. The multi-wavelength PollyXT Raman lidar system was used to determine vertical profiles of the aerosol optical properties, i.e. extinction and backscatter coefficients, Ångström exponents, lidar ratio and depolarization ratio. The mean microphysical aerosol properties, i.e. effective radius and single-scattering albedo, were retrieved with an advanced inversion algorithm. Clear differences were observed for the intensive optical properties of atmospheric layers of biomass burning and urban/industrial aerosols. Our results reveal a wide range of optical and microphysical parameters for biomass burning aerosols. This indicates probable mixing of biomass burning aerosols with desert dust particles, as well as the possible continuous influence of urban/industrial aerosol load in the region. The lidar ratio at 355 nm, the lidar ratio at 532 nm, the linear particle depolarization ratio at 355 nm and the extinction-related Ångström exponent from 355 to 532 nm were 52 ± 7 sr, 41 ± 13 sr, 0.9 ± 0.4 % and 2.3 ± 0.5, respectively, for urban/industrial aerosols, while these values were 92 ± 10 sr, 75 ± 14 sr, 3.2 ± 1.3 % and 1.7 ± 0.3, respectively, for biomass burning aerosol layers. Biomass burning particles are larger and slightly less absorbing compared to urban/industrial aerosols. The particle effective radius were found to be 0.10 ± 0.03, 0.17 ± 0.04 and 0.13 ± 0.03 µm for urban/industrial, biomass burning, and mixed aerosols, respectively, while the single-scattering albedo at 532 nm was 0.87 ± 0.06, 0.90 ± 0.06, and 0.88 ± 0.07 (at 532

  18. Optical and microphysical characterization of aerosol layers over South Africa by means of multi-wavelength depolarization and Raman lidar measurements

    NASA Astrophysics Data System (ADS)

    Giannakaki, E.; van Zyl, P. G.; Müller, D.; Balis, D.; Komppula, M.

    2015-12-01

    Optical and microphysical properties of different aerosol types over South Africa measured with a multi-wavelength polarization Raman lidar are presented. This study could assist in bridging existing gaps relating to aerosol properties over South Africa, since limited long-term data of this type is available for this region. The observations were performed under the framework of the EUCAARI campaign in Elandsfontein. The multi-wavelength PollyXT Raman lidar system was used to determine vertical profiles of the aerosol optical properties, i.e. extinction and backscatter coefficients, Ångström exponents, lidar ratio and depolarization ratio. The mean microphysical aerosol proper ties, i.e. effective radius and single scattering, albedo were retrieved with an advanced inversion algorithm. Clear differences were observed for the intensive optical properties of atmospheric layers of biomass burning and urban/industrial aerosols. Our results reveal a wide range of optical and microphysical parameters for biomass burning aerosols. This indicates probable mixing of biomass burning aerosols with desert dust particles, as well as the possible continuous influence of urban/industrial aerosol load in the region. The lidar ratio at 355 nm, the linear particle depolarization ratio at 355 nm and the extinction-related Ångström exponent from 355 to 532 nm were 52 ± 7 sr; 0.9 ± 0.4 % and 2.3 ± 0.5, respectively for urban/industrial aerosols, while these values were 92 ± 10 sr; 3.2 ± 1.3 %; 2.0 ± 0.4 respectively for biomass burning aerosols layers. Biomass burning particles are larger and slightly less absorbing compared to urban/industrial aerosols. The particle effective radius were found to be 0.10 ± 0.03, 0.17 ± 0.04 and 0.13 ± 0.03 μm for urban/industrial, biomass burning, and mixed biomass burning and desert dust aerosols, respectively, while the single scattering albedo at 532 nm were 0.87 ± 0.06, 0.90 ± 0.06, and 0.88 ± 0.07 (at 532 nm), respectively for

  19. Multi-wavelength UV-detection in capillary hydrodynamic fractionation. Data treatment for an absolute estimate of the particle size distribution

    NASA Astrophysics Data System (ADS)

    Clementi, Luis A.; Aguirre, Miren; Leiza, José R.; Gugliotta, Luis M.; Vega, Jorge R.

    2017-03-01

    A new approach is proposed for estimating the particle size distribution (PSD) of hydrophobic colloids by capillary hydrodynamic fractionation (CHDF) based on UV-detection at several wavelengths. At each elution time, the multi-wavelength UV signal is used to estimate the instantaneous PSD at the detector cell by solving the involved inverse problem through an artificial neural network. Then, the global PSD is obtained as a weighted sum of the estimated instantaneous PSDs along the entire elution time interval. With the current approach, the estimation procedure is absolute in the sense that no calibration of diameters is required and the instrumental broadening introduced by the fractionation capillary is automatically compensated for. The proposed method was evaluated on the basis of narrow polystyrene standards, as follows: i) a single standard, to emulate a narrow unimodal PSD; ii) a mixture of three standards of relatively close average diameters, to emulate a broad unimodal PSD; and iii) a mixture of two standards of quite different average diameters, to emulate a bimodal PSD. Experimental results indicate that the new approach is able to produce adequate PSD estimates provided that the particle refractive index is known with a relatively high accuracy.

  20. Multi-wavelength properties of IGR J05007-7047 (LXP 38.55) and identification as a Be X-ray binary pulsar in the LMC

    NASA Astrophysics Data System (ADS)

    Vasilopoulos, G.; Haberl, F.; Delvaux, C.; Sturm, R.; Udalski, A.

    2016-09-01

    We report on the results of a ˜40-d multi-wavelength monitoring of the Be X-ray binary system IGR J05007-7047 (LXP 38.55). During that period the system was monitored in the X-rays using the Swift telescope and in the optical with multiple instruments. When the X-ray luminosity exceeded 1036 erg s-1 we triggered an XMM-Newton ToO observation. Timing analysis of the photon events collected during the XMM-Newton observation reveals coherent X-ray pulsations with a period of 38.551(3) s (1σ), making it the 17th known high-mass X-ray binary pulsar in the LMC. During the outburst, the X-ray spectrum is fitted best with a model composed of an absorbed power law (Γ = 0.63) plus a high-temperature blackbody (kT ˜2 keV) component. By analysing ˜12 yr of available OGLE optical data we derived a 30.776(5) d optical period, confirming the previously reported X-ray period of the system as its orbital period. During our X-ray monitoring the system showed limited optical variability while its IR flux varied in phase with the X-ray luminosity, which implies the presence of a disc-like component adding cooler light to the spectral energy distribution of the system.

  1. On-line estimation of biomass, glucose and ethanol in Saccharomyces cerevisiae cultivations using in-situ multi-wavelength fluorescence and software sensors.

    PubMed

    Odman, Peter; Johansen, Claus Lindvald; Olsson, Lisbeth; Gernaey, Krist V; Lantz, Anna Eliasson

    2009-10-26

    Batch bioreactor cultivations using Saccharomyces cerevisiae at high (190-305 gl(-1) glucose) or low (21-25 gl(-1) glucose) gravity conditions were monitored on-line using multi-wavelength fluorescence (MWF) and standard monitoring sensors. Partial least squares models were calibrated for the prediction of cell dry weight (CDW), ethanol and consumed glucose, using the two data types separately. The low gravity cultivations (LGCs) consisted of two phases (glucose consumption with concomitant ethanol production followed by ethanol consumption after glucose depletion), which proved difficult to model using one and the same model for both phases. Segmented modelling, using different models for the two phases, improved the predictions significantly. The prediction models calibrated on standard on-line process data displayed similar or lower root mean square error of prediction (RMSEP) compared to the fluorescence models. The best prediction models for high gravity cultivations (HGCs) had RMSEPs of 1.0 gl(-1) CDW, 1.8 gl(-1) ethanol and 5.0 gl(-1) consumed glucose, corresponding to 4%, 2% and 2% of the respective concentration intervals. Corresponding numbers in low gravity models were 0.3 gl(-1) CDW, 0.7 gl(-1) ethanol and 1.0 gl(-1) consumed glucose, corresponding to 4%, 8% and 4% of the respective concentration intervals.

  2. THE WYOMING SURVEY FOR H{alpha}. III. A MULTI-WAVELENGTH LOOK AT ATTENUATION BY DUST IN GALAXIES OUT TO z {approx} 0.4

    SciTech Connect

    Moore, Carolynn A.; Dale, Daniel A.; Barlow, Rebecca J.; Cohen, Seth A.; Cook, David O.; Johnson, L. C.; Kattner, ShiAnne M.; Staudaher, Shawn M.; Lee, Janice C.

    2010-07-15

    We report results from the Wyoming Survey for H{alpha} (WySH), a comprehensive four-square degree survey to probe the evolution of star-forming galaxies over the latter half of the age of the universe. We have supplemented the H{alpha} data from WySH with infrared data from the Spitzer Wide-area Infrared Extragalactic Survey and ultraviolet data from the Galaxy Evolution Explorer Deep Imaging Survey. This data set provides a multi-wavelength look at the evolution of the attenuation by dust, and here we compare a traditional measure of dust attenuation (L(TIR)/L(FUV)) to a diagnostic based on a recently developed robust star formation rate (SFR) indicator, [Ha{sub obs}+24{mu}m]/Ha{sub obs}. With such data over multiple epochs, the evolution in the attenuation by dust with redshift can be assessed. We present results from the ELAIS-N1 and Lockman Hole regions at z {approx} 0.16, 0.24, 0.32, and 0.40. While the ensemble averages of both diagnostics are relatively constant from epoch to epoch, each epoch individually exhibits a larger attenuation by dust for higher SFRs. Hence, an epoch-to-epoch comparison at a fixed SFR suggests a mild decrease in dust attenuation with redshift.

  3. Study of aerosol hygroscopic events over the Cabauw experimental site for atmospheric research (CESAR) using the multi-wavelength Raman lidar Caeli

    NASA Astrophysics Data System (ADS)

    Fernández, A. J.; Apituley, A.; Veselovskii, I.; Suvorina, A.; Henzing, J.; Pujadas, M.; Artíñano, B.

    2015-11-01

    This article presents a study of aerosol optical and microphysical properties under different relative humidity (RH) but well mixed layer conditions using optical and microphysical aerosol properties from multi-wavelength (MW) Raman lidar and in-situ aerosol observations collected at the Cabauw Experimental Site for Atmospheric Research (CESAR). Two hygroscopic events are described through 3 backscatter (β) and 2 extinction (α) coefficients which in turn provide intensive parameters such as the backscatter-related Ångström exponent (åβ) and the lidar ratio (LR). Along with it, profiles of RH were inferred from Raman lidar observations and therefore, as a result of varying humidity conditions, a shift on the aerosol optical properties can be described. Thus, it is observed that as RH increases, aerosols uptake water vapour, augment their size and consequently the åβ diminishes whereas the LR increases. The enhancement factor based on the backscatter coefficient at 532 nm, which characterizes the aerosol from hygroscopic standpoint, is also estimated. Finally, microphysical properties that are necessary for aerosol radiative forcing estimates - such as volume, effective radii, refractive index and size distribution, all vertically resolved - are retrieved using the inversion with regularization. Using this method, two hygroscopic events are described in detail.

  4. MULTI-WAVELENGTH OBSERVATIONS OF THE RADIO MAGNETAR PSR J1622-4950 AND DISCOVERY OF ITS POSSIBLY ASSOCIATED SUPERNOVA REMNANT

    SciTech Connect

    Anderson, Gemma E.; Gaensler, B. M.; Slane, Patrick O.; Drake, Jeremy J.; Rea, Nanda; Kaplan, David L.; Posselt, Bettina; Levin, Lina; Bailes, Matthew; Ramesh Bhat, N. D.; Johnston, Simon; Burke-Spolaor, Sarah; Murray, Stephen S.; Brogan, Crystal L.; Bates, Samuel; Benjamin, Robert A.; Burgay, Marta; D'Amico, Nichi; Esposito, Paolo; and others

    2012-05-20

    We present multi-wavelength observations of the radio magnetar PSR J1622-4950 and its environment. Observations of PSR J1622-4950 with Chandra (in 2007 and 2009) and XMM (in 2011) show that the X-ray flux of PSR J1622-4950 has decreased by a factor of {approx}50 over 3.7 years, decaying exponentially with a characteristic time of {tau} = 360 {+-} 11 days. This behavior identifies PSR J1622-4950 as a possible addition to the small class of transient magnetars. The X-ray decay likely indicates that PSR J1622-4950 is recovering from an X-ray outburst that occurred earlier in 2007, before the 2007 Chandra observations. Observations with the Australia Telescope Compact Array show strong radio variability, including a possible radio flaring event at least one and a half years after the 2007 X-ray outburst that may be a direct result of this X-ray event. Radio observations with the Molonglo Observatory Synthesis Telescope reveal that PSR J1622-4950 is 8' southeast of a diffuse radio arc, G333.9+0.0, which appears non-thermal in nature and which could possibly be a previously undiscovered supernova remnant (SNR). If G333.9+0.0 is an SNR then the estimates of its size and age, combined with the close proximity and reasonable implied velocity of PSR J1622-4950, suggest that these two objects could be physically associated.

  5. Dynamic characteristics of a multi-wavelength Brillouin-Raman fiber laser assisted by multiple four-wave mixing processes in a ring cavity

    NASA Astrophysics Data System (ADS)

    Shirazi, M. R.; Mohamed Taib, J.; De La Rue, R. M.; Harun, S. W.; Ahmad, H.

    2015-03-01

    Dynamic characteristics of a multi-wavelength Brillouin-Raman fiber laser (MBRFL) assisted by four-wave mixing have been investigated through the development of Stokes and anti-Stokes lines under different combinations of Brillouin and Raman pump power levels and different Raman pumping schemes in a ring cavity. For a Stokes line of order higher than three, the threshold power was less than the saturation power of its last-order Stokes line. By increasing the Brillouin pump power, the nth order anti-Stokes and the (n+4)th order Stokes power levels were unexpectedly increased almost the same before the Stokes line threshold power. It was also found out that the SBS threshold reduction (SBSTR) depended linearly on the gain factor for the 1st and 2nd Stokes lines, as the first set. This relation for the 3rd and 4th Stokes lines as the second set, however, was almost linear with the same slope before SBSTR -6 dB, then, it approached to the linear relation in the first set when the gain factor was increased to 50 dB. Therefore, the threshold power levels of Stokes lines for a given Raman gain can be readily estimated only by knowing the threshold power levels in which there is no Raman amplification.

  6. Spectral decomposition of NAD(P)H fluorescence components recorded by multi-wavelength fluorescence lifetime spectroscopy in living cardiac cells

    NASA Astrophysics Data System (ADS)

    Chorvatova, Alzbeta; Mateasik, Anton; Chorvat, Dusan, Jr.

    2013-12-01

    We report a novel analytical approach to identify individual components of a cell’s endogenous fluorescence, recorded by spectrally-resolved time-correlated single photon counting (TCSPC). Time-resolved area-normalized emission spectroscopy (TRANES) and principal component analysis (PCA) were applied to estimate the number of spectral components after metabolic modulation of cardiac cells following excitation with a 375 nm picosecond laser. Linear unmixing of TCSPC data spectrally decomposed individual components in living cells, while using characteristics of endogenously fluorescing molecules in solvents as a reference spectral database. Our data demonstrate the presence of three individual components, corresponding to the nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) in organic and inorganic solvents and to the residual flavoprotein fluorescence. The presented analytical approach offers a new alternative for the spectral separation of multi-wavelength fluorescence lifetime spectroscopy data to the conventional analysis, and opens a new possibility for the use of pattern recognition for fast resolution of components in 2D fluorescence lifetime microscopy images.

  7. Non-degenerate fs pump-probe study on InGaN with multi-wavelength second-harmonic generation.

    PubMed

    Wang, Hsiang-Chen; Lu, Yen-Cheng; Chen, Cheng-Yen; Chi, Chun-Yung; Chin, Shu-Cheng; Yang, C C

    2005-07-11

    Non-degenerate fs pump-probe experiments in the UV-visible range for ultrafast carrier dynamics study of InGaN with adjustable pump and probe photon energies are implemented with simultaneously multiwavelength second-harmonic generation (SHG) of a 10 fs Ti:sapphire laser. The multi-wavelength SHG is realized with two beta-barium borate crystals of different cutting angles. The full-widths at half-maximum of the SHG pulses are around 150 fs, which are obtained from the cross-correlation measurement with a reverse-biased 280-nm light-emitting diode as the twophoton absorption photo-detector. Such pulses are used to perform nondegenerate pump-probe experiments on an InGaN thin film, in which indium-rich nano-clusters and compositional fluctuations have been identified. Relaxation of carriers from the pump level to the probe one through the scattering-induced local thermalization (<1 ps) and then the carrier-transport-dominating global thermalization (in several ps) processes is observed.

  8. Dust Temperatures and Opacities in the Central Parsec of the Galactic Center Modeled from Analysis of Multi-Wavelength Mid-Infrared Images

    NASA Technical Reports Server (NTRS)

    Varosi, F.; Gezari, D.; Dwek, E.; Telesco, C.

    2016-01-01

    We have analyzed multi-wavelength mid-infrared images of the central parsec of the Galactic Center using a two-temperature line-of-sight (LOS) radiative transfer model at each pixel of the images, giving maps of temperatures, luminosities and opacities of the hot, warm, cold (dark)dust components. The data consists of images at nine wavelengths in the mid-infrared (N-band and Q-band) from the Thermal Region Camera and Spectrograph (T-ReCS) instrument operating at the Gemini South Observatory. The results of the LOS modeling indicate that the extinction optical depth is quite large and varies substantially over the FOV. The high-resolution images of the central parsec of the Galactic center region were obtained with T-ReCS at Gemini South in January 2004. These images provide nearly diffraction-limited resolution (approx. 0.5) of the central parsec. The T-ReCS images were taken with nine filters (3.8, 4.7, 7.7, 8.7, 9.7, 10.3, 12.3, 18.3 and 24.5m), over a field-of-view (FOV) of 20 x 20 arcsec.

  9. Mass-specific optical absorption coefficients and imaginary part of the complex refractive indices of mineral dust components measured by a multi-wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2015-01-01

    Mass-specific optical absorption coefficients (MACs) and the imaginary part (κ) of the refractive indices of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at the wavelengths of 1064, 532, 355 and 266 nm. The MAC values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. Values of κ were calculated from the measured and particle-loss-corrected data by using a Mie-theory-based retrieval algorithm. The determined values could be used for comparisons with calculated wavelength-dependent κ values typically deduced from bulk-phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk-phase measurements.

  10. Reliability of the determination of whole-blood oxygen affinity by means of blood-gas analyzers and multi-wavelength oximeters.

    PubMed

    Kwant, G; Oeseburg, B; Zijistra, W G

    1989-05-01

    Determination of the oxygen affinity of human whole blood with the help of blood-gas analyzers and multi-wavelength oximeters is compared with an accurate method for recording hemoglobin oxygen dissociation curves (Clin Chem 1982;28:1287-92). P50 (oxygen tension at half saturation; So2 = 50%) and Hill's n (delta log [So2/(1-So2)]/delta log Po2) were determined in blood of 24 healthy donors. Three slightly different procedures were used for determination of P50 on the basis of Po2, pH, Pco2, and So2 measured with each of four different blood-gas analyzer/oximeter combinations. These methods were not able to discriminate between high and low values for P50 within the normal reference interval, but never failed to detect the high oxygen affinity of blood stored for 12 days, reflected in low values of P50. The methods thus proved suitable for detecting clinically significant deviations in oxygen affinity such as occur in patients with, e.g., abnormal hemoglobins, anemias, or carbon monoxide poisoning. Determination of Hill's n by these methods did not produce useful results.

  11. Vertical distribution of optical and microphysical properties of smog aerosols measured by multi-wavelength polarization lidar in Xi'an, China

    NASA Astrophysics Data System (ADS)

    Di, Huige; Hua, Hangbo; Cui, Yan; Hua, Dengxin; He, Tingyao; Wang, Yufeng; Yan, Qing

    2017-02-01

    In this study, a multi-wavelength polarization lidar was developed at the Lidar Center for Atmosphere Remote Sensing, in Xi'an, China to study the vertical distribution of the optical and microphysical properties of smog aerosols. To better understand smog, two events with different haze conditions observed in January 2015 were analyzed in detail. Using these data, we performed a vertical characterization of smog evolution using the lidar range-squared-corrected signal and the aerosol depolarization ratio. Using inversion with regularization, we retrieved the vertical distribution of aerosol microphysical properties, including volume size distribution, volume concentration, number concentration and effective radius. We also used the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model to analyze aerosol sources during the two episodes. Our results show that the most polluted area in the lower troposphere during smog episodes is located below a height of 1 km above the ground level; under more severe smog conditions, it can be below 0.5 km. In the case of severe smog, we found a large number of spherical and fine particles concentrated in the very low troposphere, even below 0.5 km. Surprisingly, a dust layer with a slight depolarization ratio was observed above the smog layer.

  12. Multiple wavelength LED on monolithic QW structure

    NASA Astrophysics Data System (ADS)

    Zakariya, Abdullah J.; LiKamWa, Patrick

    2012-10-01

    A monolithically integrated multi-wavelength LED based on selective dielectric cap intermixing is investigated experimentally. The proposed LED emits radiation with multiple wavelength peaks from one compact easy to fabricate quantum well (QW) structure. Each wavelength has an independent emission power control, allowing the LED to radiate one or more wavelengths simultaneously. The LED material is an AlGaAs/GaAs QW p-i-n heterostructure. The device is divided into three selectively intermixed regions using an impurity-free vacancy induced intermixing technique creating localized intermixed areas. Each region is intermixed to varying extent resulting in different luminescence peaks and by separately addressing each section with its electrical current, the net emission spectrum can be fully controlled. The fabrication process starts with the growth of a 400nm thick layer of SiO2 over the whole sample using plasma enhanced chemical vapor deposition. Three regions with different SiO2 thicknesses are defined via two photolithographic and subsequent reactive ion etching steps. The sample is then annealed at 975°C for 20s to activate the intermixing of the constituent atoms of the quantum well and barrier materials. The degree of intermixing is determined by the thickness of the SiO2 cap. After removal of the SiO2 cap, contact stripes are evaporated on each region to act as an independent intensity power control for that region. Experimental results have shown that a controllable 10nm, 21nm and 33nm blue shifts of the peak wavelength of emission from that of the as-grown sample corresponding to 0, 100nm, and 400nm thick SiO2 caps respectively.

  13. A light emitting diode (LED) based spatial frequency domain imaging system for optimization of photodynamic therapy of nonmelanoma skin cancer: quantitative reflectance imaging.

    PubMed

    Saager, R B; Cuccia, D J; Saggese, S; Kelly, K M; Durkin, A J

    2013-04-01

    Photodynamic therapy (PDT) offers the potential for enhanced treatment of nonmelanoma skin cancer (NMSC) with minimal scarring. Yet, PDT has not achieved consistent long term effectiveness to gain widespread clinical acceptance for treatment of skin cancer. Therapeutic response varies between practitioners, patients and lesions. One important contributing factor is the absence of quantitative tools to perform in vivo dosimetry. To this end, we have developed a new quantitative imaging device that can be used to investigate parameters related to optimizing dosimetry. We present a spatial frequency domain imaging (SFDI) based device designed to: (1) determine the optical properties at the therapeutic wavelength, which can inform variations in light penetration depth and (2) measure the spatially resolved oxygen saturation of the skin cancer lesions and surrounding tissue. We have applied this system to a preliminary clinical study of nine skin cancer lesions. Optical properties vary greatly both spatially [101%, 48% for absorption and reduced scattering, respectively] and across patients [102%, 57%]. Blood volume maps determined using visible wavelengths (460, 525, and 630 nm) represent tissue volumes within ∼1 mm in tissue (1.17 ± 0.3 mm). Here the average total hemoglobin concentration is approximately three times greater in the lesion than that detected in normal tissue, reflecting increased vasculature typically associated with tumors. Data acquired at near infrared wavelengths (730 and 850 nm) reports tissue blood concentrations and oxygenations from the underlying dermal microvasculature (volumes reaching 4.36 ± 1.32 mm into tissue). SFDI can be used to quantitatively characterize in vivo tissue optical properties that could be useful for better informing PDT treatment parameters. Specifically, this information provides spatially resolved insight into light delivery into tissue and local tissue oxygenation, thereby providing more

  14. Multi-wavelength Laser Photoacoustics

    DTIC Science & Technology

    2012-09-01

    Photoacoustics, detection, nerve agents, DIMP, DMMP, DEMP, TEP 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF...DMMP), diethyl methyl phosphonate (DEMP), diisopropyl methyl phosphonate (DIMP), dimethyl polysiloxane (DIME), triethyl phosphate ( TEP ), tributyl...photoacoustic PAS PA spectroscopy QC quantum-cascade TBP tributyl phosphate TEP triethyl phosphate VOCs volatile organic compounds 11 NO. OF

  15. Multi-wavelength coverage of state transitions in the new black hole X-ray binary swift J1910.2-0546

    SciTech Connect

    Degenaar, N.; Maitra, D.; Reynolds, M. T.; Miller, J. M.; Reis, R. C.; King, A. L.; Gültekin, K.; Cackett, E. M.; Bailyn, C. D.; Buxton, M. M.; MacDonald, R. K. D.; Fabian, A. C.; Fox, D. B.; Rykoff, E. S.

    2014-04-01

    Understanding how black holes accrete and supply feedback to their environment is one of the outstanding challenges of modern astrophysics. Swift J1910.2-0546 is a candidate black hole low-mass X-ray binary that was discovered in 2012 when it entered an accretion outburst. To investigate the binary configuration and the accretion morphology, we monitored the evolution of the outburst for ≅3 months at X-ray, UV, optical (B, V, R, I), and near-infrared (J, H, K) wavelengths using Swift and SMARTS. The source evolved from a hard to a soft X-ray spectral state with a relatively cold accretion disk that peaked at ≅0.5 keV. A Chandra/HETG spectrum obtained during this soft state did not reveal signatures of an ionized disk wind. Both the low disk temperature and the absence of a detectable wind could indicate that the system is viewed at relatively low inclination. The multi-wavelength light curves revealed two notable features that appear to be related to X-ray state changes. First, a prominent flux decrease was observed in all wavebands ≅ 1-2 weeks before the source entered the soft state. This dip occurred in (0.6-10 keV) X-rays ≅ 6 days later than at longer wavelengths, which could possibly reflect the viscous timescale of the disk. Second, about two weeks after the source transitioned back into the hard state, the UV emission significantly increased while the X-rays steadily decayed. We discuss how these observations may reflect changes in the accretion morphology, perhaps related to the quenching/launch of a jet or the collapse/recovery of a hot flow.

  16. The application of a multi-wavelength Aethalometer to estimate iron dust and black carbon concentrations in the marine boundary layer of Cape Verde

    NASA Astrophysics Data System (ADS)

    Fialho, P.; Cerqueira, M.; Pio, C.; Cardoso, J.; Nunes, T.; Custódio, D.; Alves, C.; Almeida, S. M.; Almeida-Silva, M.; Reis, M.; Rocha, F.

    2014-11-01

    The two-component model (Fialho et al., 2006) was used to decouple the contributions of black carbon (BC) and iron oxides, present in dust, to the aerosol attenuation coefficient, measured with a multi-wavelength Aethalometer. The model results were compared with the elemental carbon (EC) and iron concentrations determined in the laboratory from the analysis of aerosol particles collected with conventional samplers. The comparison was based on one year of data obtained at Praia, Santiago Island, Cape Verde, after side by side operation of the aerosol monitoring instruments. The linear regression equation that best describes the relationship between BC concentrations, derived from the Aethalometer, and EC concentrations, derived from a PM10 high-volume sampler after filter analysis with a thermal optical method, presents a slope of 1.01 ± 0.05 and a correlation coefficient (r) of 0.90, showing that the model worked as intended to describe BC concentrations without interferences from iron dust. On the other hand, the linear regression equation that best describes the relationship between the iron concentrations derived from the Aethalometer and elemental iron concentrations, derived from a PM10 low-volume sampler after filter analysis by k0 - Instrumental Neutron Activation Analysis, presents a slope of 0.495 ± 0.014 and a correlation coefficient (r) of 0.96. These results show that the two-component model underestimated the iron concentrations in dust aerosol, which was explained by differences in the size range of particles sampled with the Aethalometer and the PM10 low-volume sampler together with differences in the size distribution of iron oxides.

  17. LARGE-AMPLITUDE VARIATIONS OF AN L/T TRANSITION BROWN DWARF: MULTI-WAVELENGTH OBSERVATIONS OF PATCHY, HIGH-CONTRAST CLOUD FEATURES

    SciTech Connect

    Radigan, Jacqueline; Jayawardhana, Ray; Lafreniere, David; Artigau, Etienne; Marley, Mark; Saumon, Didier

    2012-05-10

    We present multiple-epoch photometric monitoring in the J, H, and K{sub s} bands of the T1.5 dwarf 2MASS J21392676+0220226 (2M2139), revealing persistent, periodic (P = 7.721 {+-} 0.005 hr) variability with a peak-to-peak amplitude as high as 26% in the J band. The light curve shape varies on a timescale of days, suggesting that evolving atmospheric cloud features are responsible. Using interpolations between model atmospheres with differing cloud thicknesses to represent a heterogeneous surface, we find that the multi-wavelength variations and the near-infrared spectrum of 2M2139 can be reproduced by either (1) cool, thick cloud features sitting above a thinner cloud layer, or (2) warm regions of low condensate opacity in an otherwise cloudy atmosphere, possibly indicating the presence of holes or breaks in the cloud layer. We find that temperature contrasts between thick and thin cloud patches must be greater than 175 K and as high as 425 K. We also consider whether the observed variability could arise from an interacting binary system, but this scenario is ruled out. 2M2139 joins the T2.5 dwarf SIMP0136 discovered by Artigau and coworkers as the second L/T transition brown dwarf to display large-amplitude variability on rotational timescales, suggesting that the fragmentation of dust clouds at the L/T transition may contribute to the abrupt decline in condensate opacity and J-band brightening observed to occur over this regime.

  18. STELLAR POPULATIONS IN COMPACT GALAXY GROUPS: A MULTI-WAVELENGTH STUDY OF HCGs 16, 22, AND 42, THEIR STAR CLUSTERS, AND DWARF GALAXIES

    SciTech Connect

    Konstantopoulos, I. S.; Maybhate, A.; Charlton, J. C.; Gronwall, C.; Fedotov, K.; Desjardins, T. D.; Gallagher, S. C.; Durrell, P. R.; Mulchaey, J. S.; English, J.; Walker, L. M.; Johnson, K. E.; Tzanavaris, P.

    2013-06-20

    We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 ''associates'' (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

  19. Stellar Populations in Compact Galaxy Groups: a Multi-wavelength Study of HCGs 16, 22, and 42, Their Star Clusters, and Dwarf Galaxies

    NASA Technical Reports Server (NTRS)

    Konstantopoulos, I. S.; Maybhate, A.; Charlton, J. C.; Fedotov, K.; Durrell, P. R.; Mulchaey, J. S.; English, J.; Desjardins, T. D.; Gallagher, S. C.; Walker, L. M.; Johnson, K. E.; Tzanavaris, Panayiotis; Gronwall, C.

    2013-01-01

    We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy.We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 "associates" (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

  20. High-performance size exclusion chromatography with a multi-wavelength absorbance detector study on dissolved organic matter characterisation along a water distribution system.

    PubMed

    Huang, Huiping; Sawade, Emma; Cook, David; Chow, Christopher W K; Drikas, Mary; Jin, Bo

    2016-06-01

    This study examined the associations between dissolved organic matter (DOM) characteristics and potential nitrification occurrence in the presence of chloramine along a drinking water distribution system. High-performance size exclusion chromatography (HPSEC) coupled with a multiple wavelength detector (200-280nm) was employed to characterise DOM by molecular weight distribution, bacterial activity was analysed using flow cytometry, and a package of simple analytical tools, such as dissolved organic carbon, absorbance at 254nm, nitrate, nitrite, ammonia and total disinfectant residual were also applied and their applicability to indicate water quality changes in distribution systems were also evaluated. Results showed that multi-wavelength HPSEC analysis was useful to provide information about DOM character while changes in molecule weight profiles at wavelengths less than 230nm were also able to be related to other water quality parameters. Correct selection of the UV wavelengths can be an important factor for providing appropriate indicators associated with different DOM compositions. DOM molecular weight in the range of 0.2-0.5kDa measured at 210nm correlated positively with oxidised nitrogen concentration (r=0.99), and the concentrations of active bacterial cells in the distribution system (r=0.85). Our study also showed that the changes of DOM character and bacterial cells were significant in those sampling points that had decreases in total disinfectant residual. HPSEC-UV measured at 210nm and flow cytometry can detect the changes of low molecular weight of DOM and bacterial levels, respectively, when nitrification occurred within the chloraminated distribution system. Copyright © 2016. Published by Elsevier B.V.

  1. Late Time Multi-Wavelength Observations of Swift J1644+5734: A Luminous Optical/IR Bump and Quiescent X-Ray Emission

    NASA Technical Reports Server (NTRS)

    Levan, A. J.; Tanvir, N. R.; Brown, G. C.; Metzger, B.D.; Page, K. L.; Cenko, S. B.; O'Brien, P. T.; Lyman, J. D.; Wiersema, K.; Stanway, E. R.; hide

    2016-01-01

    We present late time multi-wavelength observations of Swift J1644+57, suggested to be a relativistic tidal disruption flare (TDF). Our observations extend to greater than 4 years from discovery and show that 1.4 years after outburst the relativistic jet switched off on a timescale less than tens of days, corresponding to a power-law decay faster than t (sup -70). Beyond this point weak X-rays continue to be detected at an approximately constant luminosity of L (sub X) approximately equal to 5 times 10 (sup 42) ergs per second and are marginally inconsistent with a continuing decay of t (sup minus 5 divided by 3), similar to that seen prior to the switch-off. Host photometry enables us to infer a black hole mass of M (mass) (sub BH (black hole) equal to 3 times 10 (sup 6) the mass of the sun, consistent with the late time X-ray luminosity arising from sub-Eddington accretion onto the black hole in the form of either an unusually optically faint active galactic nucleus or a slowly varying phase of the transient. Optical/IR observations show a clear bump in the light curve at timescales of 30 to 50 days, with a peak magnitude (corrected for host galaxy extinction) of M (sub R) approximately equal to minus 22 to minus 23. The luminosity of the bump is significantly higher than seen in other, nonrelativisticTDFs and does not match any re-brightening seen at X-ray or radio wavelengths. Its luminosity, light curve shape, and spectrum are broadly similar to those seen in superluminous supervnovae, although subject to large uncertainties in the correction of the significant host extinction. We discuss these observations in the context of both TDF and massive star origins for Swift J1644+5734 and other candidate relativistic tidal flares.

  2. UV-TO-FIR ANALYSIS OF SPITZER/IRAC SOURCES IN THE EXTENDED GROTH STRIP. I. MULTI-WAVELENGTH PHOTOMETRY AND SPECTRAL ENERGY DISTRIBUTIONS

    SciTech Connect

    Barro, Guillermo; Perez-Gonzalez, P. G.; Gallego, J.; Villar, V.; Zamorano, J.; Ashby, M. L. N.; Kajisawa, M.; Yamada, T.; Miyazaki, S.

    2011-03-15

    We present an IRAC 3.6+4.5 {mu}m selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived from the analysis of the multi-wavelength data. In this paper, we describe the method used to build coherent spectral energy distributions (SEDs) for all the sources. In a forthcoming companion paper, we analyze those SEDs to obtain robust estimations of stellar parameters such as photometric redshifts, stellar masses, and star formation rates. The catalog comprises 76,936 sources with [3.6] {<=} 23.75 mag (85% completeness level of the IRAC survey in the EGS) over 0.48 deg{sup 2}. For approximately 16% of this sample, we are able to deconvolve the IRAC data to obtain robust fluxes for the multiple counterparts found in ground-based optical images. Typically, the SEDs of the IRAC sources in our catalog count with more than 15 photometric data points, spanning from the ultraviolet wavelengths probed by GALEX to the far-infrared observed by Spitzer, and going through ground- and space-based optical and near-infrared data taken with 2-8 m class telescopes. Approximately 95% and 90% of all IRAC sources are detected in the deepest optical and near-infrared bands. These fractions are reduced to 85% and 70% for S/N > 5 detections in each band. Only 10% of the sources in the catalog have optical spectroscopy and redshift estimations. Almost 20% and 2% of the sources are detected by MIPS at 24 and 70 {mu}m, respectively. We also cross-correlate our catalog with public X-ray and radio catalogs. Finally, we present the Rainbow Navigator public Web interface utility, designed to browse all the data products resulting from this work, including images, spectra, photometry, and stellar parameters.

  3. A three-year multi-wavelength study of the very-high-energy γ-ray blazar 1ES 0229+200

    SciTech Connect

    Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Behera, B.; Chen, X.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Benbow, W.; Cerruti, M.; Berger, K.; Bird, R.; Bouvier, A.; Byrum, K.; Ciupik, L.; Connolly, M. P.; Cui, W.; Duke, C.; Dumm, J. E-mail: jeremy.s.perkins@nasa.gov; and others

    2014-02-10

    The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Γ ∼ 2.5), very-high-energy (VHE; E > 100 GeV) emitting γ-ray blazar. VHE measurements of this active galactic nucleus have been used to place constraints on the intensity of the extragalactic background light and the intergalactic magnetic field (IGMF). A multi-wavelength study of this object centered around VHE observations by Very Energetic Radiation Imaging Telescope Array System (VERITAS) is presented. This study obtained, over a period of three years, an 11.7 standard deviation detection and an average integral flux F(E > 300 GeV) = (23.3 ± 2.8{sub stat} ± 5.8{sub sys}) × 10{sup –9} photons m{sup –2} s{sup –1}, or 1.7% of the Crab Nebula's flux (assuming the Crab Nebula spectrum measured by H.E.S.S). Supporting observations from Swift and RXTE are analyzed. The Swift observations are combined with previously published Fermi observations and the VHE measurements to produce an overall spectral energy distribution which is then modeled assuming one-zone synchrotron-self-Compton emission. The χ{sup 2} probability of the TeV flux being constant is 1.6%. This, when considered in combination with measured variability in the X-ray band, and the demonstrated variability of many TeV blazars, suggests that the use of blazars such as 1ES 0229+200 for IGMF studies may not be straightforward and challenges models that attribute hard TeV spectra to secondary γ-ray production along the line of sight.

  4. Multi-wavelength and time-domain diffuse optical tomography data processing by using a material basis and Mellin-Laplace transform

    NASA Astrophysics Data System (ADS)

    Hervé, Lionel; Planat-Chrétien, Anne; Di Sieno, Laura; Berger, Michel; Puszka, Agathe; Dalla Mora, Alberto; Contini, Davide; Boso, Gianluca; Dinten, Jean-Marc

    2014-03-01

    In order to increase sensitivity in the depth of diffusive media and to separate chromophores with distinct spectral signatures, we developed a method to process time-domain/multi-wavelength diffuse optical acquisitions: 3D Reconstructions of chromophore concentrations are performed with an algorithm based on the use of Mellin-Laplace Transform and material basis. A noise weighted data matching term is optimized by using the conjugated gradients method without expressing the Jacobian matrix of the system. As the algorithm uses reference measurements on a known medium, it does not require measurements or computations of the instrument response function of the system. Validations are performed in the reflectance geometry on a tissue-mimicking phantom composed of intralipid and black ink and a cylindrical blue dye inclusion with a radius of 4mm located at 15mm in depth. The optical tomography setup includes a laser whose picosecond pulses are injected via an optical fiber to the probed diffusive medium and the light collected by two fibers (located 15mm apart from the source), is sent to a Single-Photon Avalanche Diode (SPAD) connected to a Time-Correlated Single-Photon Counting (TCSPC) board. The source and two detectors scan the surface of the medium so as to provide 30 source-detector couples, 900 time-bins and 5 wavelength signals. 3D reconstructions performed on the black ink and blue dye materials on a mesh of around 10000 nodes show that we are able to detect, localize and determine the composition of the inclusion and the background.

  5. Late Time Multi-wavelength Observations of Swift J1644+5734: A Luminous Optical/IR Bump and Quiescent X-Ray Emission

    NASA Astrophysics Data System (ADS)

    Levan, A. J.; Tanvir, N. R.; Brown, G. C.; Metzger, B. D.; Page, K. L.; Cenko, S. B.; O'Brien, P. T.; Lyman, J. D.; Wiersema, K.; Stanway, E. R.; Fruchter, A. S.; Perley, D. A.; Bloom, J. S.

    2016-03-01

    We present late time multi-wavelength observations of Swift J1644+57, suggested to be a relativistic tidal disruption flare (TDF). Our observations extend to >4 years from discovery and show that 1.4 years after outburst the relativistic jet switched off on a timescale less than tens of days, corresponding to a power-law decay faster than t-70. Beyond this point weak X-rays continue to be detected at an approximately constant luminosity of LX ˜ 5 × 1042 erg s-1 and are marginally inconsistent with a continuing decay of t-5/3, similar to that seen prior to the switch-off. Host photometry enables us to infer a black hole mass of MBH = 3 × 106 M⊙, consistent with the late time X-ray luminosity arising from sub-Eddington accretion onto the black hole in the form of either an unusually optically faint active galactic nucleus or a slowly varying phase of the transient. Optical/IR observations show a clear bump in the light curve at timescales of 30-50 days, with a peak magnitude (corrected for host galaxy extinction) of MR ˜ -22 to -23. The luminosity of the bump is significantly higher than seen in other, non-relativistic TDFs and does not match any re-brightening seen at X-ray or radio wavelengths. Its luminosity, light curve shape, and spectrum are broadly similar to those seen in superluminous supervnovae, although subject to large uncertainties in the correction of the significant host extinction. We discuss these observations in the context of both TDF and massive star origins for Swift J1644+5734 and other candidate relativistic tidal flares.

  6. Discovery of VHE γ-rays from the blazar 1ES 1215+303 with the MAGIC telescopes and simultaneous multi-wavelength observations

    NASA Astrophysics Data System (ADS)

    Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Ansoldi, S.; Asensio, M.; Backes, M.; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Hose, J.; Hrupec, D.; Huber, B.; Jankowski, F.; Jogler, T.; Kadenius, V.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Niedzwiecki, A.; Nieto, D.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Perez-Torres, M. A.; Persic, M.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puerto Gimenez, I.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; Berdyugin, A.; Buson, S.; Järvelä, E.; Larsson, S.; Lähteenmäki, A.; Tammi, J.

    2012-08-01

    Context. We present the discovery of very high energy (VHE, E > 100 GeV) γ-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes and simultaneous multi-wavelength data in a broad energy range from radio to γ-rays. Aims: We study the VHE γ-ray emission from 1ES 1215+303 and its relation to the emissions in other wavelengths. Methods: Triggered by an optical outburst, MAGIC observed the source in 2011 January - February for 20.3 h. The target was monitored in the optical R-band by the KVA telescope that also performed optical polarization measurements. We triggered target of opportunity observations with the Swift satellite and obtained simultaneous and quasi-simultaneous data from the Fermi Large Area Telescope and from the Metsähovi radio telescope. We also present the analysis of older MAGIC data taken in 2010. Results: The MAGIC observations of 1ES 1215+303 carried out in 2011 January - February resulted in the first detection of the source at VHE with a statistical significance of 9.4σ. Simultaneously, the source was observed in a high optical and X-ray state. In 2010 the source was observed in a lower state in optical, X-ray, and VHE, while the GeV γ-ray flux and the radio flux were comparable in 2010 and 2011. The spectral energy distribution obtained with the 2011 data can be modeled with a simple one zone SSC model, but it requires extreme values for the Doppler factor or the electron energy distribution.

  7. INTEGRAL FIELD SPECTROSCOPY AND MULTI-WAVELENGTH IMAGING OF THE NEARBY SPIRAL GALAXY NGC 5668 : AN UNUSUAL FLATTENING IN METALLICITY GRADIENT

    SciTech Connect

    Marino, R. A.; Gil de Paz, A.; Castillo-Morales, A.; Perez-Gonzalez, P. G.; Gallego, J.; Zamorano, J.; Sanchez, S. F.

    2012-07-20

    We present an analysis of the full bidimensional optical spectral cube of the nearby spiral galaxy NGC 5668, observed with the Pmas fiber PAcK Integral Field Unit (IFU) at the Calar Alto observatory 3.5 m telescope. We make use of broadband imaging to provide further constraints on the evolutionary history of the galaxy. This data set will allow us to improve our understanding of the mechanisms that drive the evolution of disks. We investigated the properties of 62 H II regions and concentric rings in NGC 5668 and derived maps in ionized-gas attenuation and chemical (oxygen) abundances. We find that while inward of r {approx}36'' {approx} 4.4 kpc {approx} 0.36 (D{sub 25}/2) the derived O/H ratio follows the radial gradient typical of spiral galaxies, the abundance gradient beyond r {approx} 36'' flattens out. The analysis of the multi-wavelength surface brightness profiles of NGC 5668 is performed by fitting these profiles with those predicted by chemo-spectrophotometric evolutionary models of galaxy disks. From this, we infer a spin and circular velocity of {lambda} = 0.053 and v{sub c} = 167 km s{sup -1}, respectively. The metallicity gradient and rotation curve predicted by this best-fitting galaxy model nicely match the values derived from the IFU observations, especially within r {approx}36''. The same is true for the colors despite some small offsets and a reddening in the bluest colors beyond that radius. On the other hand, deviations of some of these properties in the outer disk indicate that a secondary mechanism, possibly gas transfer induced by the presence of a young bar, must have played a role in shaping the recent chemical and star formation histories of NGC 5668.

  8. Tuneable and stable multi-wavelength thulium-doped ring-cavity fibre laser based on Sagnac loop and Mach-Zehnder filter utilizing thin-core fibre

    NASA Astrophysics Data System (ADS)

    He, Wei; Zhu, Lianqing; Dong, Mingli; Luo, Fei

    2016-12-01

    A multi-wavelength thulium-doped fibre laser based on a Sagnac loop and a Mach-Zehnder filter was designed and experimentally demonstrated. In this ring-cavity fibre laser, the Sagnac loop was composed of 2 m-long polarization-maintaining fibres, and the pigtail fibre core/cladding diameter of all components was 10/125 µm. A 4 m-long thin-core fibre with a 5/130 µm core/cladding diameter was spliced into the cavity to obtain the Mach-Zehnder structure. The wavelength spacings of the comb spectra of the Sagnac loop and the Mach-Zehnder filter were 3.2 nm and 20.3 nm, respectively. When the pump power was 150 mW, single-wavelength lasing occurred with 3 nm-wavelength spacing within the 1857-1897 nm range; the maximum power difference was less than 1.27 dB; the side-mode suppression ratio was greater than 32.68 dB; and the peak power fluctuations, measured over a 10 min interval, were less than 0.2 dB. A tuneable dual-wavelength lasing mode was also realized by adjusting the polarization controllers, with emission occurring simultaneously at 1874 and 1891 nm. In this case, the power fluctuations were less than 1.36 dB and 0.53 dB, respectively. A tuneable triple-wavelength lasing mode was also demonstrated, with a side-mode suppression ratio greater than 34.51 dB.

  9. Stellar Populations in Compact Galaxy Groups: A Multi-wavelength Study of HCGs 16, 22, and 42, their Star Clusters, and Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Konstantopoulos, I. S.; Maybhate, A.; Charlton, J. C.; Fedotov, K.; Durrell, P. R.; Mulchaey, J. S.; English, J.; Desjardins, T. D.; Gallagher, S. C.; Walker, L. M.; Johnson, K. E.; Tzanavaris, P.; Gronwall, C.

    2013-06-01

    We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 "associates" (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

  10. Discovery of VHE γ -rays from the blazar 1ES 1215+303 with the MAGIC telescopes and simultaneous multi-wavelength observations

    SciTech Connect

    Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Ansoldi, S.; Asensio, M.; Backes, M.; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Hose, J.; Hrupec, D.; Huber, B.; Jankowski, F.; Jogler, T.; Kadenius, V.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Niedzwiecki, A.; Nieto, D.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Perez-Torres, M. A.; Persic, M.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puerto Gimenez, I.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; Berdyugin, A.; Buson, S.; Järvelä, E.; Larsson, S.; Lähteenmäki, A.; Tammi, J.

    2012-08-15

    Here, we present the discovery of very high energy (VHE, E > 100 GeV) γ-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes and simultaneous multi-wavelength data in a broad energy range from radio to γ-rays. We also study the VHE γ-ray emission from 1ES 1215+303 and its relation to the emissions in other wavelengths. Triggered by an optical outburst, MAGIC observed the source in 2011 January - February for 20.3 h. The target was monitored in the optical R-band by the KVA telescope that also performed optical polarization measurements. Furthermore, we triggered target of opportunity observations with the Swift satellite and obtained simultaneous and quasi-simultaneous data from the Fermi Large Area Telescope and from the Metsähovi radio telescope. We also present the analysis of older MAGIC data taken in 2010. The MAGIC observations of 1ES 1215+303 carried out in 2011 January - February resulted in the first detection of the source at VHE with a statistical significance of 9.4σ. Simultaneously, the source was observed in a high optical and X-ray state. In 2010 the source was observed in a lower state in optical, X-ray, and VHE, while the GeV γ-ray flux and the radio flux were comparable in 2010 and 2011. The spectral energy distribution obtained with the 2011 data can be modeled with a simple one zone SSC model, but it requires extreme values for the Doppler factor or the electron energy distribution.

  11. Discovery of VHE γ -rays from the blazar 1ES 1215+303 with the MAGIC telescopes and simultaneous multi-wavelength observations

    DOE PAGES

    Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; ...

    2012-08-15

    Here, we present the discovery of very high energy (VHE, E > 100 GeV) γ-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes and simultaneous multi-wavelength data in a broad energy range from radio to γ-rays. We also study the VHE γ-ray emission from 1ES 1215+303 and its relation to the emissions in other wavelengths. Triggered by an optical outburst, MAGIC observed the source in 2011 January - February for 20.3 h. The target was monitored in the optical R-band by the KVA telescope that also performed optical polarization measurements. Furthermore, we triggered target of opportunitymore » observations with the Swift satellite and obtained simultaneous and quasi-simultaneous data from the Fermi Large Area Telescope and from the Metsähovi radio telescope. We also present the analysis of older MAGIC data taken in 2010. The MAGIC observations of 1ES 1215+303 carried out in 2011 January - February resulted in the first detection of the source at VHE with a statistical significance of 9.4σ. Simultaneously, the source was observed in a high optical and X-ray state. In 2010 the source was observed in a lower state in optical, X-ray, and VHE, while the GeV γ-ray flux and the radio flux were comparable in 2010 and 2011. The spectral energy distribution obtained with the 2011 data can be modeled with a simple one zone SSC model, but it requires extreme values for the Doppler factor or the electron energy distribution.« less

  12. LATE TIME MULTI-WAVELENGTH OBSERVATIONS OF SWIFT J1644+5734: A LUMINOUS OPTICAL/IR BUMP AND QUIESCENT X-RAY EMISSION

    SciTech Connect

    Levan, A. J.; Brown, G. C.; Lyman, J. D.; Stanway, E. R.; Tanvir, N. R.; Page, K. L.; O’Brien, P. T.; Wiersema, K.; Metzger, B. D.; Cenko, S. B.; Fruchter, A. S.; Perley, D. A.; Bloom, J. S.

    2016-03-01

    We present late time multi-wavelength observations of Swift J1644+57, suggested to be a relativistic tidal disruption flare (TDF). Our observations extend to >4 years from discovery and show that 1.4 years after outburst the relativistic jet switched off on a timescale less than tens of days, corresponding to a power-law decay faster than t{sup −70}. Beyond this point weak X-rays continue to be detected at an approximately constant luminosity of L{sub X} ∼ 5 × 10{sup 42} erg s{sup −1} and are marginally inconsistent with a continuing decay of t{sup −5/3}, similar to that seen prior to the switch-off. Host photometry enables us to infer a black hole mass of M{sub BH} = 3 × 10{sup 6} M{sub ⊙}, consistent with the late time X-ray luminosity arising from sub-Eddington accretion onto the black hole in the form of either an unusually optically faint active galactic nucleus or a slowly varying phase of the transient. Optical/IR observations show a clear bump in the light curve at timescales of 30–50 days, with a peak magnitude (corrected for host galaxy extinction) of M{sub R} ∼ −22 to −23. The luminosity of the bump is significantly higher than seen in other, non-relativistic TDFs and does not match any re-brightening seen at X-ray or radio wavelengths. Its luminosity, light curve shape, and spectrum are broadly similar to those seen in superluminous supervnovae, although subject to large uncertainties in the correction of the significant host extinction. We discuss these observations in the context of both TDF and massive star origins for Swift J1644+5734 and other candidate relativistic tidal flares.

  13. LEDs for Efficient Energy

    ERIC Educational Resources Information Center

    Guerin, David A.

    1978-01-01

    Light-emitting diodes (LEDs) are described and three classroom experiments are given, one to prove the, low power requirements and efficiency of LEDs, an LED on-off detector circuit, and the third an LED photoelectric smoke detector. (BB)

  14. LEDs for Efficient Energy

    ERIC Educational Resources Information Center

    Guerin, David A.

    1978-01-01

    Light-emitting diodes (LEDs) are described and three classroom experiments are given, one to prove the, low power requirements and efficiency of LEDs, an LED on-off detector circuit, and the third an LED photoelectric smoke detector. (BB)

  15. High-power tunable single- and multi-wavelength diode-pumped Nd:YAP laser in the (4)F3/2 → (4)I11/2 transition.

    PubMed

    Tzeng, Y S; Huang, Y J; Tang, C Y; Su, K W; Chen, W D; Zhang, G; Chen, Y F

    2013-11-04

    We experimentally explore the fluorescent spectrum of the Nd:YAP crystal to manifest the feasibility of tunable single- and multi-wavelength operations in the (4)F3/2 → (4)I11/2 transition. An intracavity etalon is subsequently exploited to effectively select spectral lines at 1073, 1080, and 1084 nm with the tunabilities of 0.56, 1.13, and 0.1 nm, respectively. We also experimentally obtain multi-wavelength oscillations among various intermanifold lines in the Nd:YAP crystal with the output powers on the order of several watts for each group. Employing the Cr(4+):YAG crystal to realize the passively Q-switched operation, the maximum average output powers as high as 2.3 and 3.5 W for 1073 and 1080 nm are obtained. The corresponding pulse energies at 1073 and 1080 nm are up to 177 and 159 μJ, respectively.

  16. A13K-0336: Airborne Multi-Wavelength High Spectral Resolution Lidar for Process Studies and Assessment of Future Satellite Remote Sensing Concepts

    NASA Technical Reports Server (NTRS)

    Hostetler, Chris A.; Ferrare, Rich A.; Hair, Johnathan W.; Cook, Anthony L.; Harper, David B.; Mack, Terry L.; Hare, Richard J.; Cleckner, Craig S.; Rogers, Raymond R.; Muller, Detlef; hide

    2012-01-01

    NASA Langley recently developed the world's first airborne multi-wavelength high spectral resolution lidar (HSRL). This lidar employs the HSRL technique at 355 and 532 nm to make independent, unambiguous retrievals of aerosol extinction and backscatter. It also employs the standard backscatter technique at 1064 nm and is polarization-sensitive at all three wavelengths. This instrument, dubbed HSRL-2 (the secondgeneration HSRL developed by NASA Langley), is a prototype for the lidar on NASA's planned Aerosols- Clouds-Ecosystems (ACE) mission. HSRL-2 completed its first science mission in July 2012, the Two-Column Aerosol Project (TCAP) conducted by the Department of Energy (DOE) in Hyannis, MA. TCAP presents an excellent opportunity to assess some of the remote sensing concepts planned for ACE: HSRL-2 was deployed on the Langley King Air aircraft with another ACE-relevant instrument, the NASA GISS Research Scanning Polarimeter (RSP), and flights were closely coordinated with the DOE's Gulfstream-1 aircraft, which deployed a variety of in situ aerosol and trace gas instruments and the new Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR). The DOE also deployed their Atmospheric Radiation Measurement Mobile Facility and their Mobile Aerosol Observing System at a ground site located on the northeastern coast of Cape Cod for this mission. In this presentation we focus on the capabilities, data products, and applications of the new HSRL-2 instrument. Data products include aerosol extinction, backscatter, depolarization, and optical depth; aerosol type identification; mixed layer depth; and rangeresolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). Applications include radiative closure studies, studies of aerosol direct and indirect effects, investigations of aerosol-cloud interactions, assessment of chemical transport models, air quality studies, present (e.g., CALIPSO

  17. Vertically-resolved retrievals of the atmospheric CO2 concentration using multi-wavelength pulsed lidar measurements from the ASCENDS airborne campaigns

    NASA Astrophysics Data System (ADS)

    Ramanathan, A.; Mao, J.; Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C. J.; Kawa, S. R.

    2013-12-01

    Vertically resolved remote sensing measurements of CO2 can greatly aid the understanding of terrestrial processes compared to column-averaged measurements since the effects of such processes occur mainly in planetary boundary layer of the atmosphere. Using the NASA GSFC CO2 sounder, a multi-wavelength pulsed lidar system for CO2 remote sensing, we demonstrate vertically resolved CO2 concentration measurements from the ASCENDS (Active Sensing of Co2 Emissions over Nights, Days and Seasons) airborne campaigns of July-August 2011 and February-March 2013. Our instrument uses an IPDA (Integrated Path Differential Absorption) approach probing 30 wavelengths across a 1572.335 nm CO2 absorption line. Our pulsed approach gives us height-resolved (from time-of-flight) atmospheric backscatter information, allowing us to resolve lidar reflections from clouds and the ground. When flying over thin or broken clouds, the instrument simultaneously measures the absorption to each individual cloud layer and ground. This allows us to split the vertical CO2 column into layers (cloud-slicing of the atmosphere) and solve for the CO2 concentration of each column layer. Data from a flight over Iowa, USA in August 2011 making measurements through broken cumulus clouds showed not only a 15-20 ppm reduction in the column averaged CO2 measurements due to the summer biosphere, but also a further 10 ppm decrease in the CO2 concentration in the air below the cloud tops (in the planetary boundary layer) compared to the column average. Line shape information can also be used to resolve several vertical layers from measurements in clear air. Lower atmospheric CO2 has a broader absorption feature compared to that of upper atmospheric CO2 and so changes in lower atmospheric or boundary layer CO2 affect the total column absorption line shape differently compared to those of the upper atmosphere. The CO2 sounder instrument samples the entire absorption line, potentially allowing for resolving several

  18. 4.5 Years of Multi-wavelength Observations of MRK 421 During the ARGO-YBJ and FERMI Common Operation Time

    NASA Astrophysics Data System (ADS)

    Bartoli, B.; Bernardini, P.; Bi, X. J.; Cao, Z.; Catalanotti, S.; Chen, S. Z.; Chen, T. L.; Cui, S. W.; Dai, B. Z.; D'Amone, A.; Danzengluobu; De Mitri, I.; D'Ettorre Piazzoli, B.; Di Girolamo, T.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Iacovacci, M.; Iuppa, R.; Jia, H. Y.; Labaciren; Li, H. J.; Liu, C.; Liu, J.; Liu, M. Y.; Lu, H.; Ma, L. L.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Mastroianni, S.; Montini, P.; Ning, C. C.; Perrone, L.; Pistilli, P.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xue, L.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, L.; Zhang, X. Y.; Zhang, Y.; Zhao, J.; Zhaxiciren; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; ARGO-YBJ Collaboration

    2016-01-01

    We report on the extensive multi-wavelength observations of the blazar Markarian 421 (Mrk 421) covering radio to γ-rays, during the 4.5 year period of ARGO-YBJ and Fermi common operation time, from 2008 August to 2013 February. These long-term observations, extending over an energy range of 18 orders of magnitude, provide a unique chance to study the variable emission of Mrk 421. In particular, due to the ARGO-YBJ and Fermi data, the entire energy range from 100 MeV to 10 TeV is covered without any gap. In the observation period, Mrk 421 showed both low- and high-activity states at all wavebands. The correlations among flux variations in different wavebands were analyzed. The X-ray flux is clearly correlated with the TeV γ-ray flux, while the GeV γ-rays only show a partial correlation with the TeV γ-rays. Radio and UV fluxes seem to be weakly or not correlated with the X-ray and γ-ray fluxes. Seven large flares, including five X-ray flares and two GeV γ-ray flares with variable durations (3-58 days), and one X-ray outburst phase were identified and used to investigate the variation of the spectral energy distribution with respect to a relative quiescent phase. During the outburst phase and the seven flaring episodes, the peak energy in X-rays is observed to increase from sub-keV to a few keV. The TeV γ-ray flux increases up to 0.9-7.2 times the flux of the Crab Nebula. The behavior of GeV γ-rays is found to vary depending on the flare, a feature that leads us to classify flares into three groups according to the GeV flux variation. Finally, the one-zone synchrotron self-Compton model was adopted to describe the emission spectra. Two out of three groups can be satisfactorily described using injected electrons with a power-law spectral index around 2.2, as expected from relativistic diffuse shock acceleration, whereas the remaining group requires a harder injected spectrum. The underlying physical mechanisms responsible for different groups may be related to

  19. Ground-based network observation using Mie-Raman lidars and multi-wavelength Raman lidars and algorithm to retrieve distributions of aerosol components

    NASA Astrophysics Data System (ADS)

    Nishizawa, Tomoaki; Sugimoto, Nobuo; Matsui, Ichiro; Shimizu, Atsushi; Hara, Yukari; Itsushi, Uno; Yasunaga, Kazuaki; Kudo, Rei; Kim, Sang-Woo

    2017-02-01

    We improved two-wavelength polarization Mie-scattering lidars at several main sites of the Asian dust and aerosol lidar observation network (AD-Net) by adding a nitrogen Raman scatter measurement channel at 607 nm and have conducted ground-based network observation with the improved Mie-Raman lidars (MRL) in East Asia since 2009. This MRL provides 1α+2β+1δ data at nighttime: extinction coefficient (α532), backscatter coefficient (β532), and depolarization ratio (δ532) of particles at 532 nm and an attenuated backscatter coefficient at 1064 nm (βat,1064). Furthermore, we developed a Multi-wavelength Mie-Raman lidar (MMRL) providing 2α+3β+2δ data (α at 355 and 532 nm; β at 355 and 532; βat at 1064 nm; and δ at 355 and 532 nm) and constructed MMRLs at several main sites of the AD-Net. We identified an aerosol-rich layer and height of the planetary boundary layer (PBL) using βat,1064 data, and derived aerosol optical properties (AOPs, for example, αa, βa, δa, and lidar ratio (Sa)). We demonstrated that AOPs cloud be derived with appropriate accuracy. Seasonal means of AOPs in the PBL were evaluated for each MRL observation site using three-year data from 2010 through 2012; the AOPs changed according to each season and region. For example, Sa,532 at Fukue, Japan, were 44±15 sr in winter and 49±17 in summer; those at Seoul, Korea, were 56±18 sr in winter and 62±15 sr in summer. We developed an algorithm to estimate extinction coefficients at 532 nm for black carbon, dust, sea-salt, and air-pollution aerosols consisting of a mixture of sulfate, nitrate, and organic-carbon substances using the 1α532+2β532 and 1064+1δ532 data. With this method, we assume an external mixture of aerosol components and prescribe their size distributions, refractive indexes, and particle shapes. We applied the algorithm to the observed data to demonstrate the performance of the algorithm and determined the vertical structure for each aerosol component.

  20. Fast, multi-wavelength, efficiency-enhanced pixelated devices based on InGaAs/InAlAs quantum-well

    NASA Astrophysics Data System (ADS)

    Ganbold, T.; Antonelli, M.; Biasiol, G.; Cucini, R.; Cautero, G.; Menk, R. H.

    2015-03-01

    Several applications utilizing either synchrotron or conventional light sources require fast and efficient pixelated detectors. In order to cover a wide range of experiments, this work investigates the possibility to use InGaAs/InAlAs quantum well devices as photon detectors for a broad range of energies. Owing to their direct, low-energy band gap and high electron mobility, such devices may be used also at room temperature as multi-wavelength sensors from visible light to hard X-rays. Furthermore, internal charge-amplification mechanism can be applied for very low signal levels, while the high carrier mobility allows the design of very fast photon detectors with sub-nanosecond response times.Samples were grown by solid source molecular beam epitaxy on GaAs substrates. Metamorphic In0.75Ga0.25As/ In0.75Al0.25As heterostructures were obtained by relaxing the strain due to the lattice mismatch in the substrate by means of a composition-graded buffer layer. A two-dimensional electron gas forming in an In0.75Ga0.25As quantum well is sandwiched between In0.75Al0.25As barriers and is modulation-doped by a Si δ on its top. The samples have been pixelated by using standard photolithographic techniques. In order to fit commercially available readout chips, a pixelated sensor with pixel size of 172 × 172 μ m2 is currently under development. A small-scale version of the pixelated quantum well sensor has been preliminary tested with 100-fs-wide laser pulses and X-ray synchrotron radiation. The reported results indicate that these sensors respond with 100-ps rise-times to ultra-fast laser pulses. Synchrotron X-ray tests show how these devices exhibit high charge collection efficiencies, which can be imputed to the charge-multiplication effect of the 2D electron gas inside the well.

  1. 4.5 YEARS OF MULTI-WAVELENGTH OBSERVATIONS OF MRK 421 DURING THE ARGO-YBJ AND FERMI COMMON OPERATION TIME

    SciTech Connect

    Bartoli, B.; Catalanotti, S.; Piazzoli, B. D’Ettorre; Girolamo, T. Di; Bernardini, P.; D’Amone, A.; Mitri, I. De; Bi, X. J.; Cao, Z.; Chen, S. Z.; Feng, Zhaoyang; Gou, Q. B.; Guo, Y. Q.; Chen, T. L.; Danzengluobu; Cui, S. W.; Dai, B. Z.; Sciascio, G. Di; Feng, C. F.; Feng, Zhenyong; Collaboration: ARGO-YBJ Collaboration; and others

    2016-01-15

    We report on the extensive multi-wavelength observations of the blazar Markarian 421 (Mrk 421) covering radio to γ-rays, during the 4.5 year period of ARGO-YBJ and Fermi common operation time, from 2008 August to 2013 February. These long-term observations, extending over an energy range of 18 orders of magnitude, provide a unique chance to study the variable emission of Mrk 421. In particular, due to the ARGO-YBJ and Fermi data, the entire energy range from 100 MeV to 10 TeV is covered without any gap. In the observation period, Mrk 421 showed both low- and high-activity states at all wavebands. The correlations among flux variations in different wavebands were analyzed. The X-ray flux is clearly correlated with the TeV γ-ray flux, while the GeV γ-rays only show a partial correlation with the TeV γ-rays. Radio and UV fluxes seem to be weakly or not correlated with the X-ray and γ-ray fluxes. Seven large flares, including five X-ray flares and two GeV γ-ray flares with variable durations (3–58 days), and one X-ray outburst phase were identified and used to investigate the variation of the spectral energy distribution with respect to a relative quiescent phase. During the outburst phase and the seven flaring episodes, the peak energy in X-rays is observed to increase from sub-keV to a few keV. The TeV γ-ray flux increases up to 0.9–7.2 times the flux of the Crab Nebula. The behavior of GeV γ-rays is found to vary depending on the flare, a feature that leads us to classify flares into three groups according to the GeV flux variation. Finally, the one-zone synchrotron self-Compton model was adopted to describe the emission spectra. Two out of three groups can be satisfactorily described using injected electrons with a power-law spectral index around 2.2, as expected from relativistic diffuse shock acceleration, whereas the remaining group requires a harder injected spectrum. The underlying physical mechanisms responsible for different groups may be

  2. Discovery of VHE γ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9-311909

    NASA Astrophysics Data System (ADS)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker, J.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Göring, D.; Häffner, S.; Hague, J. D.; Hahn, J.; Hampf, D.; Harris, J.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Krayzel, F.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Mohamed, M.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    2012-06-01

    1RXS J101015.9-311909 is a galaxy located at a redshift of z=0.14 hosting an active nucleus (called AGN) belonging to the class of bright BL Lac objects. Observations at high (HE, E > 100 MeV) and very high (VHE, E > 100 GeV) energies provide insights into the origin of very energetic particles present in such sources and the radiation processes at work. We report on results from VHE observations performed between 2006 and 2010 with the H.E.S.S. instrument, an array of four imaging atmospheric Cherenkov telescopes. H.E.S.S. data have been analysed with enhanced analysis methods, making the detection of faint sources more significant. VHE emission at a position coincident with 1RXS J101015.9-311909 is detected with H.E.S.S. for the first time. In a total good-quality livetime of about 49 h, we measure 263 excess counts, corresponding to a significance of 7.1 standard deviations. The photon spectrum above 0.2 TeV can be described by a power-law with a photon index of Γ = 3.08 ± 0.42stat ± 0.20sys. The integral flux above 0.2 TeV is about 0.8% of the flux of the Crab nebula and shows no significant variability over the time reported. In addition, public Fermi/LAT data are analysed to search for high energy emission from the source. The Fermi/LAT HE emission in the 100 MeV to 200 GeV energy range is significant at 8.3 standard deviations in the chosen 25-month dataset. UV and X-ray contemporaneous observations with the Swift satellite in May 2007 are also reported, together with optical observations performed with the atom telescope located at the H.E.S.S. site. Swift observations reveal an absorbed X-ray flux of F(0.3-7) keV = 1.04+0.04-0.05 × 10-11 erg cm-2 s-1 in the 0.3-7 keV range. Finally, all the available data are used to study the multi-wavelength properties of the source. The spectral energy distribution (SED) can be reproduced using a simple one-zone Synchrotron Self Compton (SSC) model with emission from a region with a Doppler factor of 30 and a

  3. Fermi Large Area Telescope And Multi-Wavelength Observations Of The Flaring Activity Of PKS 1510-089 Between 2008 September And 2009 June

    SciTech Connect

    Abdo, A. A.

    2010-09-10

    We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, the source was characterized by a complex variability at optical, UV, and γ-ray bands, on timescales down to 6-12 hr. The brightest γ-ray isotropic luminosity, recorded on 2009 March 26, was sime2 × 1048 erg s–1. The spectrum in the Fermi Large Area Telescope energy range shows a mild curvature described well by a log-parabolic law, and can be understood as due to the Klein-Nishina effect. The γ-ray flux has a complex correlation with the other wavelengths. There is no correlation at all with the X-ray band, a weak correlation with the UV, and a significant correlation with the optical flux. The γ-ray flux seems to lead the optical one by about 13 days. From the UV photometry, we estimated a black hole mass of sime5.4 × 108 M ⊙ and an accretion rate of sime0.5 M ⊙ yr–1. Although the power in the thermal and non-thermal outputs is smaller compared to the very luminous and distant FSRQs, PKS 1510-089 exhibits a quite large Compton dominance and a prominent big blue bump (BBB) as observed in the most powerful γ-ray quasars. The BBB was still prominent during the historical maximum optical state in 2009 May, but the optical/UV spectral index was softer than in the quiescent state. This seems to indicate that the BBB was not completely dominated by the synchrotron emission during the highest optical state. We model the broadband spectrum assuming a leptonic scenario in which the inverse Compton emission is dominated by the scattering of soft photons produced externally to the jet. The resulting model-dependent jet energetic content is compatible with a scenario in which the jet is powered by the accretion disk, with a total efficiency within the Kerr black hole limit.

  4. Fermi Large Area Telescope And Multi-Wavelength Observations Of The Flaring Activity Of PKS 1510-089 Between 2008 September And 2009 June

    DOE PAGES

    Abdo, A. A.

    2010-09-10

    We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, the source was characterized by a complex variability at optical, UV, and γ-ray bands, on timescales down to 6-12 hr. The brightest γ-ray isotropic luminosity, recorded on 2009 March 26, was sime2 × 1048 erg s–1. The spectrum in the Fermi Large Area Telescope energy range shows a mild curvature described well by a log-parabolic law, and can be understood as due to the Klein-Nishinamore » effect. The γ-ray flux has a complex correlation with the other wavelengths. There is no correlation at all with the X-ray band, a weak correlation with the UV, and a significant correlation with the optical flux. The γ-ray flux seems to lead the optical one by about 13 days. From the UV photometry, we estimated a black hole mass of sime5.4 × 108 M ⊙ and an accretion rate of sime0.5 M ⊙ yr–1. Although the power in the thermal and non-thermal outputs is smaller compared to the very luminous and distant FSRQs, PKS 1510-089 exhibits a quite large Compton dominance and a prominent big blue bump (BBB) as observed in the most powerful γ-ray quasars. The BBB was still prominent during the historical maximum optical state in 2009 May, but the optical/UV spectral index was softer than in the quiescent state. This seems to indicate that the BBB was not completely dominated by the synchrotron emission during the highest optical state. We model the broadband spectrum assuming a leptonic scenario in which the inverse Compton emission is dominated by the scattering of soft photons produced externally to the jet. The resulting model-dependent jet energetic content is compatible with a scenario in which the jet is powered by the accretion disk, with a total efficiency within the Kerr black hole limit.« less

  5. The ionized absorber and nuclear environment of IRAS 13349+2438: multi-wavelength insights from coordinated Chandra HETGS, HST STIS, HET and Spitzer IRS

    NASA Astrophysics Data System (ADS)

    Lee, Julia C.; Kriss, Gerard A.; Chakravorty, Susmita; Rahoui, Farid; Young, Andrew J.; Brandt, William N.; Hines, Dean C.; Ogle, Patrick M.; Reynolds, Christopher S.

    2013-04-01

    We present results from a multi-wavelength infrared (IR)-to-X-ray campaign of the infrared bright (but highly optical-ultraviolet extincted) quasi-stellar object (QSO) IRAS 13349+2438 obtained with the Chandra High Energy Transmission Grating Spectrometer (HETGS), the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS), the Hobby-Eberly Telescope (HET) 8 m and the Spitzer Infrared Spectrometer (IRS). Based on HET optical spectra of [O III], we refine the redshift of IRAS 13349 to be z = 0.108 53. The weakness of the [O III] in combination with strong Fe II in the HET spectra reveals extreme Eigenvector-1 characteristics in IRAS 13349, but the 2468 km s-1 width of the Hβ line argues against a narrow-line Seyfert 1 classification; on average, IR, optical and optical-ultraviolet (UV) spectra show IRAS 13349 to be a typical QSO. Independent estimates based on the Hβ line width and fits to the IRAS 13349 spectral energy distribution (SED) both give a black hole mass of MBH = 109 M⊙. The heavily reddened STIS UV spectra reveal for the first time blueshifted absorption from Ly α, N V and C IV, with components at systemic velocities of -950 km s^{-1} and -75 km s^{-1} . The higher velocity UV lines are coincident with the lower ionization (ξ ˜ 1.6) WA-1 warm absorber lines seen in the X-rays with the HETGS. In addition, a ξ ˜ 3.4 WA-2 is also required by the data, while a ξ ˜ 3 WA-3 is predicted by theory and seen at less significance; all detected X-ray absorption lines are blueshifted by ˜ 700-900 km s-1 . Theoretical models comparing different ionizing SEDs reveal that including the UV (i.e. the accretion disc) as part of the ionizing continuum has strong implications for the conclusions one would draw about the thermodynamic stability of the warm absorber. Specific to IRAS 13349, we find that an X-ray-UV ionizing SED favours a continuous distribution of ionization states in a smooth flow (this paper) versus discrete clouds in pressure

  6. Probing the Structure and Morphology of X-ray and Gamma-ray Binaries Using a Multi-Wavelength, Multi-MIssion Approach

    NASA Astrophysics Data System (ADS)

    Coley, Joel Barry

    2016-01-01

    This thesis focuses on High-Mass X-ray Binaries and their gamma-ray precursors, consisting of a compact object and an optical companion. Matter lost from the companion is accreted by the compact object where the gravitational potential energy is converted into X-ray radiation. The predominant high-energy emissions in gamma-ray binaries are in the MeV to TeV bandpasses. These are attributed to relativistic jets in microquasars or shocks from winds of the donor star and pulsar powered by rapid rotation of the neutron star.I use multi-wavelength observations with RXTE, MAXI, Swift, Suzaku, Fermi and ATCA to provide detailed temporal and spectral information on several X-ray binaries and one gamma-ray binary, 1FGL J1018.6-5856.My survey of the eclipsing HMXBs IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016 and XTE J1855-026 demonstrates that the physical parameters of both stellar components can be constrained. In IGR J16393-4643, spectral types of B0 V or B0-5 III are found to be consistent with the eclipse duration and Roche-lobe size, but the previously proposed spectral types in IGR J16418- 4532 and IGR J16479-4514 were not. Also found to be consistent with the eclipse half-angle and Roche-lobe size were the mass donor spectral types of IGR J18027-2016 and XTE J1855-026.4U 1210-64 was postulated to be an HMXB powered by the Be mechanism. Long-term observations show distinct high and low states and a 6.7101±0.0005 day modulation. A sharp dip interpreted to be an eclipse is found in the folded light curves. The eclipse half-angle is not consistent with the previously proposed spectral type B5 V, pointing to possible spectral types of B0 V or B0-5 III.The gamma-ray binary 1FGL J1018.6-5856, discovered by the Fermi Large Area Telescope, consists of an O6 V((f)) star and a suspected rapidly spinning pulsar. I exploit the 6.5 yr gamma-ray data to search for long-term changes in the properties of the 16.531±0.006 day orbital modulation. The best

  7. LED minilidar for Mars rover

    NASA Astrophysics Data System (ADS)

    Shiina, Tatsuo; Yamada, Sonoko; Senshu, Hiroki; Otobe, Naohito; Hashimoto, George; Kawabata, Yasuhiro

    2016-10-01

    A mini-lidar to observe the activity of Martian atmosphere is developed. The 10cm-cube LED mini-lidar was designed to be onboard a Mars rover. The light source of the mini-lidar is a high powered LED of 385nm. LED was adopted as light source because of its toughness against circumference change and physical shock for launch. The pulsed power and the pulse repetition frequency of LED beam were designed as 0.75W (=7.5nJ/10ns) and 500kHz, respectively. Lidar echoes were caught by the specially designed Cassegrain telescope, which has the shorter telescope tube than the usual to meet the 10cm-cube size limit. The high-speed photon counter was developed to pursue to the pulse repetition frequency of the LED light. The measurement range is no shorter than 30m depending back-ground condition. Its spatial resolution was improved as 0.15m (=1ns) by this photon counter. The demonstrative experiment was conducted at large wind tunnel facility of Japan Meteorological Agency. The measurement target was smoke of glycerin particles. The smoke was flowed in the wind tunnel with wind speed of 0 - 5m. Smoke diffusion and its propagation due to the wind flow were observed by the LED mini-lidar. This result suggests that the developed lidar can pursue the structure and the motion of dust devil of >2m.

  8. LED Color Characteristics

    SciTech Connect

    2012-01-01

    Color quality is an important consideration when evaluating LED-based products for general illumination. This fact sheet reviews the basics regarding light and color and summarizes the most important color issues related to white-light LED systems.

  9. Increased Efficiency LED

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio Oliviera (Inventor); Rogowski, Robert S. (Inventor)

    1996-01-01

    In a semiconductor light emitting diode (LED) a large proportion of the light produced will be internally reflected when it strikes the end face of the LED at a semiconductor-air interface. This is due to the high index of refraction of most LED semiconductor materials. This problem may be partially overcome by modification of the shape of the LED by a reverse taper of the sides of the LED. Light is redirected by the taper to strike the interface at an angle closer to normal. This allows light to exit the LED that would be totally internally reflected in an untapered LED. The novelty of the present invention lies in the tapering of the sides of the LED for increased through transmission of light. Prior art devices have made use surface modifications such as roughening, addition of guiding layers, use of index matching materials and hemispherical shaping of the emitting end of the LED. Current technology LEDs have a transmission efficiency of only a few percent. An increase in this efficiency would be of great value to any technology that makes use of LEDs for light generation. The present invention is related to LAR 1 5050-SB, Collection of Light from Optical Fibers of NA greater than 1.

  10. Broadband Radiometric LED Measurements

    PubMed Central

    Eppeldauer, G. P.; Cooksey, C. C.; Yoon, H. W.; Hanssen, L. M.; Podobedov, V. B.; Vest, R. E.; Arp, U.; Miller, C. C.

    2017-01-01

    At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or re