Science.gov

Sample records for deep optical photometry

  1. WINGS: A WIde-field Nearby Galaxy-cluster Survey. II. Deep optical photometry of 77 nearby clusters

    NASA Astrophysics Data System (ADS)

    Varela, J.; D'Onofrio, M.; Marmo, C.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W. J.; Dressler, A.; Kjærgaard, P.; Moles, M.; Pignatelli, E.; Poggianti, B. M.; Valentinuzzi, T.

    2009-04-01

    Context: This is the second paper of a series devoted to the WIde Field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long term project which is gathering wide-field, multi-band imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04 < z < 0.07) located far from the galactic plane (|b|≥ 20°). The main goal of this project is to establish a local reference for evolutionary studies of galaxies and galaxy clusters. Aims: This paper presents the optical (B,V) photometric catalogs of the WINGS sample and describes the procedures followed to construct them. We have paid special care to correctly treat the large extended galaxies (which includes the brightest cluster galaxies) and the reduction of the influence of the bright halos of very bright stars. Methods: We have constructed photometric catalogs based on wide-field images in B and V bands using SExtractor. Photometry has been performed on images in which large galaxies and halos of bright stars were removed after modeling them with elliptical isophotes. Results: We publish deep optical photometric catalogs (90% complete at V ~ 21.7, which translates to ˜ M^*_V+6 at mean redshift), giving positions, geometrical parameters, and several total and aperture magnitudes for all the objects detected. For each field we have produced three catalogs containing galaxies, stars and objects of “unknown” classification (~6%). From simulations we found that the uncertainty of our photometry is quite dependent of the light profile of the objects with stars having the most robust photometry and de Vaucouleurs profiles showing higher uncertainties and also an additional bias of ~-0.2^m. The star/galaxy classification of the bright objects (V < 20) was checked visually making negligible the fraction of misclassified objects. For fainter objects, we found that simulations do not provide reliable estimates of the possible misclassification and therefore we have compared our data

  2. The ROSAT Deep Survey. 2; Optical Identification, Photometry and Spectra of X-Ray Sources in the Lockman Field

    NASA Technical Reports Server (NTRS)

    Schmidt, M.; Hasinger, G.; Gunn, J.; Schneider, D.; Burg, R.; Giacconi, R.; Lehmann, I.; MacKenty, J.; Truemper, J.; Zamorani, G.

    1998-01-01

    The ROSAT Deep Survey includes a complete sample of 50 X-ray sources with fluxes in the 0.5 - 2 keV band larger than 5.5 x 10(exp -15)erg/sq cm/s in the Lockman field (Hasinger et al., Paper 1). We have obtained deep broad-band CCD images of the field and spectra of many optical objects near the positions of the X-ray sources. We define systematically the process leading to the optical identifications of the X-ray sources. For this purpose, we introduce five identification (ID) classes that characterize the process in each case. Among the 50 X-ray sources, we identify 39 AGNs, 3 groups of galaxies, 1 galaxy and 3 galactic stars. Four X-ray sources remain unidentified so far; two of these objects may have an unusually large ratio of X-ray to optical flux.

  3. A Young Stellar Cluster within the RCW41 H II Region: Deep NIR Photometry and Optical/NIR Polarimetry

    NASA Astrophysics Data System (ADS)

    Santos, Fábio P.; Roman-Lopes, Alexandre; Franco, Gabriel A. P.

    2012-06-01

    The RCW41 star-forming region is embedded within the Vela Molecular Ridge, hosting a massive stellar cluster surrounded by a conspicuous H II region. Understanding the role of interstellar magnetic fields and studying the newborn stellar population is crucial to building a consistent picture of the physical processes acting on this kind of environment. We carried out a detailed study of the interstellar polarization toward RCW41 with data from an optical and near-infrared polarimetric survey. Additionally, deep near-infrared images from the 3.5 meter New Technology Telescope were used to study the photometric properties of the embedded young stellar cluster, revealing several YSO candidates. By using a set of pre-main-sequence isochrones, a mean cluster age in the range 2.5-5.0 million years was determined, and evidence of sequential star formation was revealed. An abrupt decrease in R-band polarization degree was noticed toward the central ionized area, probably due to low grain alignment efficiency caused by the turbulent environment and/or the weak intensity of magnetic fields. The distortion of magnetic field lines exhibits dual behavior, with the mean orientation outside the area approximately following the borders of the star-forming region and directed radially toward the cluster inside the ionized area, in agreement with simulations of expanding H II regions. The spectral dependence of polarization allowed a meaningful determination of the total-to-selective extinction ratio by fittings of the Serkowski relation. Furthermore, a large rotation of polarization angle as a function of wavelength was detected toward several embedded stars. Based on observations collected at the European Southern Observatory (La Silla, Chile), National Optical Astronomy Observatory (CTIO, Chile), and Observatório do Pico dos Dias, operated by Laboratório Nacional de Astrofísica (LNA/MCT, Brazil).

  4. A YOUNG STELLAR CLUSTER WITHIN THE RCW41 H II REGION: DEEP NIR PHOTOMETRY AND OPTICAL/NIR POLARIMETRY

    SciTech Connect

    Santos, Fabio P.; Franco, Gabriel A. P.; Roman-Lopes, Alexandre E-mail: franco@fisica.ufmg.br

    2012-06-01

    The RCW41 star-forming region is embedded within the Vela Molecular Ridge, hosting a massive stellar cluster surrounded by a conspicuous H II region. Understanding the role of interstellar magnetic fields and studying the newborn stellar population is crucial to building a consistent picture of the physical processes acting on this kind of environment. We carried out a detailed study of the interstellar polarization toward RCW41 with data from an optical and near-infrared polarimetric survey. Additionally, deep near-infrared images from the 3.5 meter New Technology Telescope were used to study the photometric properties of the embedded young stellar cluster, revealing several YSO candidates. By using a set of pre-main-sequence isochrones, a mean cluster age in the range 2.5-5.0 million years was determined, and evidence of sequential star formation was revealed. An abrupt decrease in R-band polarization degree was noticed toward the central ionized area, probably due to low grain alignment efficiency caused by the turbulent environment and/or the weak intensity of magnetic fields. The distortion of magnetic field lines exhibits dual behavior, with the mean orientation outside the area approximately following the borders of the star-forming region and directed radially toward the cluster inside the ionized area, in agreement with simulations of expanding H II regions. The spectral dependence of polarization allowed a meaningful determination of the total-to-selective extinction ratio by fittings of the Serkowski relation. Furthermore, a large rotation of polarization angle as a function of wavelength was detected toward several embedded stars.

  5. Hubble Deep Field guide star photometry

    NASA Astrophysics Data System (ADS)

    Zwintz, K.; Kuschnig, R.; Weiss, W. W.; Gray, R. O.; Jenkner, H.

    1999-03-01

    Since the advent of asteroseismology as a promising innovative tool for investigating internal stellar structure, numerous attempts to detect solar type oscillations in distant stars have been conducted. The three Fine Guidance Sensors of the Hubble Space Telescope can contribute to asteroseismology, but only after the data have been corrected for systematic effects, the South Atlantic Anomaly and terrestrial stray light being the most important. We have applied these corrections and obtained essentially photon noise-limited photometry for two guide stars used during the Hubble Deep Field program. Ground-based spectral classification has revealed that the brighter of the two guide stars is a solar-type star with a spectral type of G2mG0iv. Fine Guidance Sensor photometry for this star gives a noise level in the amplitude spectrum of only 23 ppm, which makes it a good candidate for detecting stochastically driven oscillations. We compare our result with theoretical predictions. The second guide star was classified as K1v and therefore is not a candidate for solar type oscillations. Based on observations made with the NASA/ESA {\\it Hubble Space Telescope}, obtained from the data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  6. The RINGS Survey: Optical Broadband Photometry

    NASA Astrophysics Data System (ADS)

    Kuzio de Naray, Rachel; Mitchell, Carl; Spekkens, Kristine; Sellwood, Jerry; Williams, Ted

    2016-01-01

    We have targeted a sample of 19 nearby spiral galaxies, the RSS Imaging and Spectroscopy Nearby Galaxy Survey (RINGS), for detailed study of their mass distributions. We have obtained Fabry-Perot Halpha velocity fields using the Southern African Large Telescope (SALT), 21-cm HI observations using the Very Large Array (VLA), and optical broadband BVRI photometry using the CTIO 0.9m and KPNO 2.1m telescopes. We present the results of the photometric component of the survey including multicolor images, surface brightness profiles, and DiskFit structural models.

  7. A REST-FRAME OPTICAL VIEW ON z {approx} 4 GALAXIES. I. COLOR AND AGE DISTRIBUTIONS FROM DEEP IRAC PHOTOMETRY OF THE IUDF10 AND GOODS SURVEYS

    SciTech Connect

    Oesch, P. A.; Illingworth, G. D.; Gonzalez, V.; Holden, B. P.; Magee, D.; Trenti, M.; Van Dokkum, P. G.

    2013-08-01

    We present a study of rest-frame UV-to-optical color distributions for z {approx} 4 galaxies based on the combination of deep HST/ACS+WFC3/IR data with Spitzer/IRAC imaging. In particular, we use new, ultra-deep data from the IRAC Ultradeep Field program (IUDF10), together with previous, public IRAC data over the GOODS fields. Our sample contains a total of {approx}2600 galaxies selected as B-dropout Lyman-break Galaxies in the HUDF and its deep parallel field HUDF09-2, as well as GOODS-North/South. This sample is used to investigate the UV continuum slopes {beta} and Balmer break colors (J{sub 125} - [4.5]) as a function of rest-frame optical luminosity (using [4.5] to avoid optical emission lines). We find that galaxies at M{sub z} < -21.5 (roughly corresponding to L{sup *}{sub z{approx}4}) are significantly redder than their lower luminosity counterparts. The UV continuum slopes and the J{sub 125} - [4.5] colors are well correlated, indicating that the dust reddening at these redshifts is better described by an SMC-like extinction curve, rather than the typically assumed Calzetti reddening. After dust correction, we find that the galaxy population shows mean stellar population ages in the range 10{sup 8.5} to 10{sup 9} yr, with a dispersion of {approx}0.5 dex, and only weak trends as a function of luminosity. Only a small fraction of galaxies shows Balmer break colors consistent with extremely young ages, younger than 100 Myr. Under the assumption of smooth star-formation histories, this fraction is 12%-19% for galaxies at M{sub z} < -19.75. Our results are consistent with a gradual build-up of stars and dust in galaxies at z > 4 with only a small fraction of stars being formed in short, intense bursts of star-formation.

  8. The Spitzer Local Volume Legacy (LVL) global optical photometry

    NASA Astrophysics Data System (ADS)

    Cook, David O.; Dale, Daniel A.; Johnson, Benjamin D.; Van Zee, Liese; Lee, Janice C.; Kennicutt, Robert C.; Calzetti, Daniela; Staudaher, Shawn M.; Engelbracht, Charles W.

    2014-11-01

    We present the global optical photometry of 246 galaxies in the Local Volume Legacy (LVL) survey. The full volume-limited sample consists of 258 nearby (D < 11 Mpc) galaxies whose absolute B-band magnitude span a range of -9.6 < MB < -20.7 mag. A composite optical (UBVR) data set is constructed from observed UBVR and Sloan Digital Sky Survey ugriz imaging, where the ugriz magnitudes are transformed into UBVR. We present photometry within three galaxy apertures defined at UV, optical, and IR wavelengths. Flux comparisons between these apertures reveal that the traditional optical R25 galaxy apertures do not fully encompass extended sources. Using the larger IR apertures, we find colour-colour relationships where later type spiral and irregular galaxies tend to be bluer than earlier type galaxies. These data provide the missing optical emission from which future LVL studies can construct the full panchromatic (UV-optical-IR) spectral energy distributions.

  9. EXTENDED PHOTOMETRY FOR THE DEEP2 GALAXY REDSHIFT SURVEY: A TESTBED FOR PHOTOMETRIC REDSHIFT EXPERIMENTS

    SciTech Connect

    Matthews, Daniel J.; Newman, Jeffrey A.; Coil, Alison L.; Cooper, Michael C.; Gwyn, Stephen D. J. E-mail: janewman@pitt.edu E-mail: m.cooper@uci.edu

    2013-02-15

    This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys: the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs. We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to provide a more uniform data set. We have also used this improved photometry to predict DEEP2 BRI photometry in regions where only poorer measurements were available previously. In addition, we have included improved astrometry tied to SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog contains {approx}27, 000 objects with full ugriz photometry as well as robust spectroscopic redshift measurements, 64% of which have r > 23. By combining the secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz photometry, we have created a catalog that can be used as an excellent testbed for future photo-z studies, including tests of algorithms for surveys such as LSST and DES.

  10. Multicolour Optical Photometry of Active Geostationary Satellites

    NASA Astrophysics Data System (ADS)

    Jolley, A.; Wade, G.; Bedard, D.

    Although broadband photometry has been used to infer information about artificial satellites since soon after the launch of Sputnik 1, the development of photometric techniques for non-resolved space object identification or characterisation has been hampered by the large number of variables involved. Many individual studies, and some long ongoing experiments, have used costly metre-class telescopes to obtain data despite other experiments demonstrating that much more flexible and affordable small aperture telescopes may be suitable for the task. In addition, due to the highly time consuming and weather dependent nature of obtaining photometric observations, many studies have suffered from data sets of limited size, or relied upon simulations to support their claims. With this in mind, an experiment was conducted with the aim of determining the utility of small aperture telescopes for conducting broadband photometry of satellites for the purpose of non-resolved space object identification and characterisation. A 14 inch Celestron CG-14 telescope was used to gain multiple night-long, high temporal resolution data sets of six active geostationary satellites. The results of the experiment cast doubt on the efficacy of some of the previous approaches to obtaining and analysing photometric data. It was discovered that geostationary satellite lightcurves can vary to a greater degree than has generally been recognised, and colour ratios vary considerably with changes in the illumination/observation geometry, making it difficult to use colour for satellite discrimination. Evidence was also detected of variations in the spectral energy distribution of sunlight reflected off satellite surface materials, which could have implications for surface material characterisation and techniques that aim to separate satellite body and solar panel contributions to the total observed spectra.

  11. Optical Photometry of the Local Volume Legacy (LVL) Survey

    NASA Astrophysics Data System (ADS)

    Cook, David O.; Dale, D. A.; van Zee, L.; Johnson, B. D.; Lee, J. C.; Cales, S.; LVL Team

    2014-01-01

    We present new optical (UBVR) imaging of 258 nearby (D < 11 Mpc) galaxies in the Local Volume Legacy (LVL) survey. The volume limited sample is dominated by dwarf galaxies, however, the sample as a whole probes many global galaxy environments. This photometry completes the panchromatic data set which spans a wide wavelength range (1500 Å - 160 μm). This study focuses on GALEX (FUV & NUV), optical (UBVR), 2MASS (JHK), and Spitzer (3.6 μm, 4.5 μm, 5 um, 8 μm, & 24 μm) data. Photometry was performed with three separate apertures (defined from the FUV, 3.6 μm, and optical) to allow direct photometric comparisons between galaxies with consistent apertures. The wide wavelength coverage with uniform apertures across many environments will facilitate studying the effect of secular galaxy evolution and environment on galaxy-wide properties. Furthermore, the proximity of these galaxies will yield a wealth information on sub-kpc scales since individual star-forming regions can be identified and studied with the same wide wavelength coverage. We present the basic optical properties and SEDs of these galaxies and their relationships to the full panchromatic data set to evince underlying physical processes.

  12. Optical photometry and spectroscopy of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Ilkiewicz, K.; Swierczynski, E.; Belcheva, M.; Dimitrov, D.

    2013-08-01

    We report optical BV photometry and spectroscopy of Nova Del 2013, carried out between August 14.88 UT and August 15.08 UT. Using a 60 cm Cassegrain telescope at the Nicolaus Copernicus University Observatory (Torun, Poland) we estimated the V brightness of the Nova to be 6.31+/-0.02 mag and 6.18+/-0.03 mag on Aug. 14.94 UT and Aug. 15.02 UT respectively. HD 194113 (F2, V=8.00 mag) was used as a comparison star.

  13. Photometry of AM Herculis - A slow optical pulsar

    NASA Technical Reports Server (NTRS)

    Priedhorsky, W. C.; Krzeminski, W.

    1978-01-01

    Multicolor photometry of the X-ray binary AM Her suggests that the red component of the optical flux is closely related to the source of optical circular polarization in the system. It is concluded from the periodic modulation of flux in the U through R bands, which is particularly well-defined when plotted as color curves, that the primary and secondary minima are neither eclipses by a secondary star nor eclipses by a hot spot. It is suggested that the primary minimum in the visual light curve is the eclipse of a region of intense optical emission in the magnetic field near the surface of a degenerate dwarf by that dwarf itself.

  14. Optimal Stellar Photometry for Multi-conjugate Adaptive Optics Systems Using Science-based Metrics

    NASA Astrophysics Data System (ADS)

    Turri, P.; McConnachie, A. W.; Stetson, P. B.; Fiorentino, G.; Andersen, D. R.; Bono, G.; Massari, D.; Véran, J.-P.

    2017-04-01

    We present a detailed discussion of how to obtain precise stellar photometry in crowded fields using images from multi-conjugate adaptive optics (MCAO) systems, with the intent of informing the scientific development of this key technology for the Extremely Large Telescopes. We use deep J and K s exposures of NGC 1851 taken with the Gemini Multi-Conjugate Adaptive Optics System (GeMS) on Gemini South to quantify the performance of the instrument and to develop an optimal strategy for stellar photometry using point-spread function (PSF)-fitting techniques. We judge the success of the various methods we employ by using science-based metrics, particularly the width of the main sequence turnoff region. We also compare the GeMS photometry with the exquisite HST data in the visible of the same target. We show that the PSF produced by GeMS possesses significant spatial and temporal variability that must be accounted for during the analysis. We show that the majority of the variation of the PSF occurs within the “control radius” of the MCAO system and that the best photometry is obtained when the PSF radius is chosen to closely match this spatial scale. We identify photometric calibration as a critical issue for next-generation MCAO systems such as those on the Thirty Meter Telescope and European Extremely Large Telescope. Our final CMDs reach K s ∼ 22—below the main sequence knee—making it one of the deepest for a globular cluster available from the ground. Theoretical isochrones are in remarkable agreement with the stellar locus in our data from below the main sequence knee to the upper red giant branch.

  15. The Optical Afterglow of GRB 971214: R and J Photometry

    NASA Astrophysics Data System (ADS)

    Diercks, A. H.; Deutsch, E. W.; Castander, F. J.; Corson, C.; Gilmore, G.; Lamb, D. Q.; Tanvir, N.; Turner, E. L.; Wyse, R.

    1998-08-01

    We present an R- and J-band photometry of an optical transient that is likely to be associated with the gamma-ray burst event GRB 971214. Our first measurement took place 13 hr after the gamma-ray event. The brightness decayed with a power-law exponent α=-1.20+/-0.02, which is similar to those of GRB 970228 andGRB 970508, which had exponents of α=-1.10+/-0.04 and α=-1.141+/-0.014, respectively. The transient decayed monotonically during the first 4 days following the gamma-ray event in contrast with the optical transient associated with GRB 970508, which increased in brightness, peaking 2 days after the burst, before settling to a power-law decay.

  16. Optical and near infrared photometry of Butcher-Oemler clusters

    NASA Technical Reports Server (NTRS)

    Shier, Lisa M.; Rieke, Marcia J.

    1993-01-01

    Rich clusters of galaxies at moderate redshifts (z approx. .3) have a larger proportion of optically blue galaxies than their low redshift counterparts. Spectroscopic examination of the blue galaxies by various authors has shown that the blue galaxies are generally Seyferts, show evidence for recent star formation, or are foreground objects. Unfortunately, spectroscopy is too time consuming to be used on large samples. Thus, we have looked for a way to separate Seyferts, starbursts, ellipticals and nonmembers using photometry alone. Five moderate redshift clusters, Abell numbers 777, 963, 1758, 1961 and 2218, have been observed in the V, R and K bands. We model the spectral energy distributions of various kinds of galaxies found in clusters and derive observed colors. We have modeled the spectral energy distributions (SED) of several kinds of galaxies and compute their colors as a function of redshift. We expect to see ellipticals, spirals, starbursts, post-starburst and Seyfert galaxies. The SED of elliptical and Sbc galaxies was observed by Rieke and Rieke. The SEDs for the starburst galaxies was created by adding a reddened 10(exp 8) year old burst to a spiral galaxy SED. The post-starburst (E+A) galaxy SEDs are composed of a slightly reddened 10(exp 9) year old burst and elliptical galaxy SED. SEDs for the Seyferts were created by adding a v(exp -1.1) power law, and a hot dust thermal spectrum to the Sbc. From the SEDs the colors of galaxies at various redshifts with assorted filters were computed. Lilly & Gunn (1985) have optical and infrared photometry for a sample of galaxies in CL0024+1654 observed spectroscopically by Dressler, Gunn and Schneider (1985). We have used this data to choose the most appropriate SEDs for our starburst and post-starburst models. The most likely explanation for the optically blue colors in most cluster galaxies is star formation. Very few galaxies lie in the Seyfert locus. Abel 1758 has more Seyfert candidates than the other

  17. Thermal Emission Photometry of Deep Impact Flyby Target (163249) 2002 GT

    NASA Astrophysics Data System (ADS)

    Lim, Lucy F.; Moskovitz, N. A.; Licandro, J.; Emery, J. P.; Reddy, V.; Vilas, F.; 2002 GT Observing Team

    2013-10-01

    Near-Earth asteroid (163249) 2002 GT is now the target of a Deep Impact spacecraft flyby in Jan. 2020 (see Pittichova et al., this volume, for details of the flyby and observing campaign). Thermal emission photometry of 2002 GT was obtained from NIRI on Gemini-North in the L' and M' filters, which are centered at 3.76 and 4.68 microns respectively. J- and K-band reflectance photometry was also acquired in support of the thermal observations. The full JKL'M' set was acquired on UT 2013-Jun-13 at a solar phase angle of 53 degrees. A further set of photometry in J, K, and L' only was carried out on 2013-Jun-19 at a phase angle of 65 degrees. High water vapor conditions at Mauna Kea during this period unfortunately prevented acquisition of a second set of M' measurements. In addition, N-band photometry of 2002 GT was conducted on 2013-Jun-10 from CanariCam at the 10-meter Gran Telescopio Canarias using a beta version of the moving object guiding system. Data were acquired in three filters between 8.7 and 12.5 microns, although the limitations of the guiding are complicating the analysis. (We note that N-band observing was not offered by either Gemini or IRTF during this apparition.) Data analysis is ongoing and results will be discussed. We appreciate the efforts of the Gemini and GTC staff in support of these observing programs.

  18. Optical Photometry of BY Cam Modeled Using a Multipolar Magnetic Field Structure

    NASA Astrophysics Data System (ADS)

    Morales, John; Mason, P. A.; Zhilkin, A.; Bisikalo, D. V.; Robinson, E. L.

    2014-01-01

    We present new high-speed broad-band optical photometry of the asynchronous polar (magnetic cataclysmic variable) BY Cam. Observations were obtained at the 2.1-m Otto Struve Telescope of McDonald observatory with 3s integration times. In an attempt to understand the complex changes in accretion flow geometry, we performed full 3D MHD simulations assuming a variety of white dwarf magnetic field structures including both aligned and non-aligned dipole plus quadrupole field components. We compare model predictions with photometry and various phases of the beat cycle and find that synthetic light curves derived from a multipolar field structure are consistent with the optical photometry.

  19. Optical microscopy aims deep

    NASA Astrophysics Data System (ADS)

    Gigan, Sylvain

    2017-01-01

    A new set of imaging techniques that take advantage of scattered light may soon lead to key advances in biomedical optics, providing access to depths well beyond what is currently possible with ballistic light.

  20. VizieR Online Data Catalog: Deep VI photometry of Sgr dIrr (Beccari+, 2014)

    NASA Astrophysics Data System (ADS)

    Beccari, G.; Bellazzini, M.; Fraternali, F.; Battaglia, G.; Perina, S.; Sollima, A.; Oosterloo, T. A.; Testa, V.; Galleti, S.

    2014-10-01

    Photometric catalogue of the dwarf irregular galaxy Sagittarius. The catalogue is obtained from deep V and I band wide field photometry from VIMOS at VLT. Only sources having at least six independent magnitude estimates per filter were included in this catalogue. The average and the standard error of the mean of the independent measures obtained from the different images were adopted as the final values of the instrumental magnitude and of the uncertainty on the relative photometry. The instrumental v and i magnitudes were transformed into the Johnson-Kron-Cousins V,I photometric system using more than 70 bright stars (V<22.5) in common with the publicly available HST Wide Field and Planetary Camera 2 (WFPC2) photometry by Holtzman et al. (2006ApJS..166..534H). The instrumental coordinates were transformed into J2000 Equatorial coordinates with 2nd degree polynomials, using more than 1000 stars in common with the GSC2.2 catalog. Please see Section 2.2 for details. (1 data file).

  1. Optical Photometry of V404 Cyg (=GS2023+338)

    NASA Astrophysics Data System (ADS)

    Wagner, R. M.; Shrader, C. R.; Starrfield, S. G.

    2000-03-01

    In response to the request by Hjellming et al. in ATEL #54, Rose Finn (Steward Observatory/U. Arizona) obtained for us two R-band CCD images of V404 Cyg (=GS2023+338) on 2000 Mar 3.52 UT with the Steward Observatory Bok 2.3-m telescope and direct CCD (scale = 0.3 arcsec/pixel, airmass = 1.8, seeing = 1.7 arcsec FWHM). Photometry of V404 Cyg was obtained with respect to the comparison stars C1, C4, and C5 of Udalski and Kaluzny (1991, PASP, 103, 198), Casares et al. (1993, MNRAS, 265, 834), and our own photometry of C1 (R = 12.39).

  2. High Speed Optical Photometry of LMXBs and CVs

    NASA Astrophysics Data System (ADS)

    Mason, Paul A.; Robinson, Edward L.; Gomez, Sebastian; Gonzalez, Emmanuel; Lopez, Isaac D.; Monroy, Lorena; Price, Alex

    2013-02-01

    High speed photometry of several accreting binaries was obtained using the McDonald Observatory 2.1m telescope and ARGOS CCD photometer. A broad-band filter (BVR) was used in order to maximize flux and maintain a short (1-10s) integration time on faint targets. Such observations obtained over several years allow for variability study over time scales covering many orders of magnitude. Observations and analysis for several binaries are summarized.

  3. DEEP, WIDE-FIELD CCD PHOTOMETRY FOR THE OPEN CLUSTER NGC 3532

    SciTech Connect

    Clem, James L.; Landolt, Arlo U.; Hoard, D. W.; Wachter, Stefanie E-mail: landolt@phys.lsu.edu E-mail: wachter@ipac.caltech.edu

    2011-04-15

    We present the results of a deep, wide-field CCD survey for the open cluster NGC 3532. Our new BV(RI){sub c} photometry effectively covers a one square degree area and reaches an unprecedented depth of V {approx} 21 to reveal that NGC 3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams (CMDs), including supplementing our photometry with JHK{sub s} data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main-sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence. Our results confirm previous findings that NGC 3532 lies fairly near to the Sun [(m - M){sub 0} = 8.46 {+-} 0.05; 492{sup +12}{sub -11} pc] and has an extremely low reddening for its location near the Galactic plane [E(B - V) = 0.028 {+-} 0.006]. Moreover, an age of {approx}300 Myr has been derived for the cluster by fitting a set of overshooting isochrones to the well-populated upper main sequence. This new photometry also extends faint enough to reach the cluster white dwarf sequence, as confirmed by our photometric recovery of eight spectroscopically identified members of the cluster. Using the location of these eight members, along with the latest theoretical cooling tracks, we have identified {approx}30 additional white dwarf stars in the [V, (B - V)] CMD that have a high probability of belonging to NGC 3532. Reassuringly, the age we derive from fitting white dwarf isochrones to the locus of these stars, 300 {+-} 100 Myr, is consistent with the age derived from the turnoff. Our analysis of the photometry also includes an estimation of the binary star fraction as well as a determination of the cluster's luminosity and mass functions.

  4. A DEEP UBVRI CCD PHOTOMETRY OF SIX OPEN STAR CLUSTERS IN THE GALACTIC ANTICENTER REGION

    SciTech Connect

    Lata, Sneh; Pandey, Anil K.; Kumar, Brijesh; Bhatt, Himali; Pace, Giancarlo; Sharma, Saurabh

    2010-02-15

    We present deep UBVRI CCD photometry of six open star clusters situated in the Galactic anticenter region (l{approx} 120-200 deg.). The sample includes three unstudied (Be 6, Be 77, King 17) and three partly studied open clusters (Be 9, NGC 2186, and NGC 2304). The fundamental parameters have been determined by comparing color-color and color-magnitude diagrams with the theoretical models. The structural parameters and morphology of the clusters were discussed on the basis of radial density profiles and isodensity contours, respectively. The isodensity contours show that all the clusters have asymmetric shapes. An investigation of structural parameters indicates that the evolution of core and corona of the clusters is mainly controlled by internal relaxation processes.

  5. SEDS: The Spitzer Extended Deep Survey. Survey Design, Photometry, and Deep IRAC Source Counts

    NASA Technical Reports Server (NTRS)

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Arendt, A.; Barmby, P.; Barro, G; Bell, E. F.; Bouwens, R.; Cattaneo, A.; Croton, D.; Dave, R.; Dunlop, J. S.; Egami, E.; Faber, S.; Finlator, K.; Grogin, N. A.; Guhathakurta, P.; Hernquist, L.; Hora, J. L.; Illingworth, G.; Kashlinsky, A; Koekmoer, A. M.; Koo, D. C.; Moseley, H.

    2013-01-01

    The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg(exp 2) to a depth of 26 AB mag (3sigma) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 micron. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 +/- 1.0 and 4.4 +/- 0.8 nW / square m/sr at 3.6 and 4.5 micron to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

  6. SEDS: THE SPITZER EXTENDED DEEP SURVEY. SURVEY DESIGN, PHOTOMETRY, AND DEEP IRAC SOURCE COUNTS

    SciTech Connect

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Hernquist, L.; Hora, J. L.; Arendt, R.; Barmby, P.; Barro, G.; Faber, S.; Guhathakurta, P.; Bouwens, R.; Cattaneo, A.; Croton, D.; Dave, R.; Dunlop, J. S.; Egami, E.; Finlator, K.; Grogin, N. A.; and others

    2013-05-20

    The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg{sup 2} to a depth of 26 AB mag (3{sigma}) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 {mu}m. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 {+-} 1.0 and 4.4 {+-} 0.8 nW m{sup -2} sr{sup -1} at 3.6 and 4.5 {mu}m to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

  7. WIYN open cluster study. LXII. Comparison of isochrone systems using deep multi-band photometry of M35

    SciTech Connect

    Thompson, B.; Frinchaboy, P.; Kinemuchi, K.; Sarajedini, A.; Cohen, R.

    2014-11-01

    The current generation of stellar isochrone models exhibits non-negligible discrepancies due to variations in the input physics. The success of each model is determined by how well it fits the observations, and this paper aims to disentangle contributions from the various physical inputs. New deep, wide-field optical and near-infrared photometry (UBVRIJHK{sub S} ) of the cluster M35 is presented, against which several isochrone systems are compared: Padova, PARSEC, Dartmouth, and Y {sup 2}. Two different atmosphere models are applied to each isochrone: ATLAS9 and BT-Settl. For any isochrone set and atmosphere model, observed data are accurately reproduced for all stars more massive than 0.7 M {sub ☉}. For stars less massive than 0.7 M {sub ☉}, Padova and PARSEC isochrones consistently produce higher temperatures than observed. Dartmouth and Y{sup 2} isochrones with BT-Settl atmospheres reproduce optical data accurately; however, they appear too blue in IR colors. It is speculated that molecular contributions to stellar spectra in the near-infrared may not be fully explored, and that future study may reconcile these differences.

  8. SPITZER OBSERVATIONS OF ABELL 1763. I. INFRARED AND OPTICAL PHOTOMETRY

    SciTech Connect

    Edwards, Louise O. V.; Fadda, Dario; Biviano, Andrea

    2010-02-15

    We present a photometric analysis of the galaxy cluster Abell 1763 at visible and infrared wavelengths. Included are fully reduced images in r', J, H, and K{sub s} obtained using the Palomar 200in telescope, as well as the IRAC and MIPS images from Spitzer. The cluster is covered out to approximately 3 virial radii with deep 24 {mu}m imaging (a 5{sigma} depth of 0.2 mJy). This same field of {approx}40' x 40' is covered in all four IRAC bands as well as the longer wavelength MIPS bands (70 and 160 {mu}m). The r' imaging covers {approx}0.8 deg{sup 2} down to 25.5 mag, and overlaps with most of the MIPS field of view. The J, H, and K{sub s} images cover the cluster core and roughly half of the filament galaxies, which extend toward the neighboring cluster, Abell 1770. This first, in a series of papers on Abell 1763, discusses the data reduction methods and source extraction techniques used for each data set. We present catalogs of infrared sources (with 24 and/or 70 {mu}m emission) and their corresponding emission in the optical (u', g', r', i', z'), and near- to far-IR (J, H, K{sub s} , IRAC, and MIPS 160 {mu}m). We provide the catalogs and reduced images to the community through the NASA/IPAC Infrared Science Archive.

  9. Photometry and polarimetry. [optical properties of Titan atmosphere

    NASA Technical Reports Server (NTRS)

    Veverka, J.

    1974-01-01

    A review of available information on the photometry, polarimetry, and narrow band spectrophotometry of Titan discusses five major categories: (1) brightness and color as a function of orbital position; (2) brightness and color as a function of solar phase angle; (3) geometric and bond albedo; (4) reflectance as a function of wavelength; and (5) polarization as a function of solar phase angle. It is concluded that a Saturn-like cloud model may be required to explain the sum of polarimetric and photometric observations.

  10. Stellar populations in edge-on galaxies from deep CCD surface photometry, 1: NGC 5907

    NASA Technical Reports Server (NTRS)

    Morrison, Heather L.; Boroson, Todd A.; Harding, Paul

    1994-01-01

    We present extremely deep charge coupled device (CCD) surface photometry of the edge-on Sc galaxy NGC 5907. Our data reach reliably to a surface brightness of R=27 mag/sq arcsec, some two magnitudes fainter than any previous work. We obtained this improvement using a 2048X2048 CCD with a wide (approximately 24 min) field, which made it possible to sky subtract directly from the galaxy frame, and by taking many dark sky flatfields. Our analysis of these data, using a full 2D model fitting procedure with a detailed error model, confirm the thin disk parameters of van der Kruit & Searle (1981). In particular, we confirm that the galaxy's disk has a radial cutoff and a constant scale height with radius. We find evidence for a stellar warp in this system, which has the same orientation as the H I warp. Our deep data also confirm that NGC 5907 has no thick disk. This suggests that theories of thick disk formation from star formation in the early stages of disk collapse, or by secular heating mechanisms, are unlikely to be correct, because they would predict that every galaxy would have a thick disk. Thick disk formation from the accretion of satellite galaxies is more likely.

  11. Deep NIR photometry of H I galaxies in the Zone of Avoidance

    NASA Astrophysics Data System (ADS)

    Williams, W. L.; Kraan-Korteweg, R. C.; Woudt, P. A.

    2014-09-01

    Current studies of the peculiar velocity flow field in the local Universe are limited by either the lack of detection or accurate photometry for galaxies at low Galactic latitudes. The contribution to the dynamics of the Local Group of the largely unknown mass distribution in this `Zone of Avoidance' (ZoA) remains controversial. We present here the results of a pilot project to obtain deep near-infrared (NIR) observations of galaxies detected in the systematic Parkes deep H I survey of the ZoA(HIZOA) - 578 galaxies with recession velocities out to 6000 km s-1 were observed with the 1.4 m InfraRed Survey Facility SIRIUS (Simultaneous InfraRed Imager for Unbiased Surveys) camera providing J, H and Ks imaging 2 mag deeper than 2MASS. After star subtraction, the resulting isophotal magnitudes and inclinations of ZoA galaxies are of sufficient accuracy (magnitude errors under 0.1 mag even at high extinction) to ultimately be used to determine cosmic flow fields `in' the ZoA via the NIR Tully-Fisher relation. We further used the observed NIR colours to assess the ratio of the true extinction to the Diffuse Infrared Background Experiment/IRAS extinction deep into the dust layers of the Milky Way. The derived ratio was found to be 0.87 across the HIZOA survey region with no significant variation with Galactic latitude or longitude. This value is in excellent agreement with the completely independently derived factor of 0.86 by Schlafly & Finkbeiner based on Sloan data far away from the Milky Way.

  12. Optical BVRI photometry of common proper motion F/G/K+M wide separation binaries

    SciTech Connect

    Li, Ting; Marshall, Jennifer L.; Williams, Patrick; Chavez, Joy; Lépine, Sébastien

    2014-10-01

    We present optical (BVRI) photometric measurements of a sample of 76 common proper motion wide separation main-sequence binary pairs. The pairs are composed of a F-, G-, or K-type primary star and an M-type secondary. The sample is selected from the revised NLTT catalog and the LSPM catalog. The photometry is generally precise to 0.03 mag in all bands. We separate our sample into two groups, dwarf candidates and subdwarf candidates, using the reduced proper motion diagram constructed with our improved photometry. The M subdwarf candidates in general have larger V – R colors than the M dwarf candidates at a given V – I color. This is consistent with an average metallicity difference between the two groups, as predicted by the PHOENIX/BT-Settl models. The improved photometry will be used as input into a technique to determine the metallicities of the M-type stars.

  13. Deep Washington photometry of inconspicuous star cluster candidates in the Large Magellanic Cloud

    SciTech Connect

    Choudhury, Samyaday; Subramaniam, Annapurni; Piatti, Andrés E.

    2015-02-01

    We present deep Washington photometry of 45 poorly populated star cluster candidates in the Large Magellanic Cloud (LMC). We have performed a systematic study to estimate the parameters of the cluster candidates by matching theoretical isochrones to the cleaned and dereddened cluster color–magnitude diagrams. We were able to estimate the basic parameters for 33 clusters, out of which 23 are identified as single clusters and 10 are found to be members of double clusters. The other 12 cluster candidates have been classified as possible clusters/asterisms. About 50% of the true clusters are in the 100–300 Myr age range, whereas some are older or younger. We have discussed the distribution of age, location, and reddening with respect to field, as well as the size of true clusters. The sizes and masses of the studied sample are found to be similar to that of open clusters in the Milky Way. Our study adds to the lower end of cluster mass distribution in the LMC, suggesting that the LMC, apart from hosting rich clusters, also has formed small, less massive open clusters in the 100–300 Myr age range.

  14. Galaxy And Mass Assembly: accurate panchromatic photometry from optical priors using LAMBDAR

    NASA Astrophysics Data System (ADS)

    Wright, A. H.; Robotham, A. S. G.; Bourne, N.; Driver, S. P.; Dunne, L.; Maddox, S. J.; Alpaslan, M.; Andrews, S. K.; Bauer, A. E.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Clarke, C.; Cluver, M.; Davies, L. J. M.; Grootes, M. W.; Holwerda, B. W.; Hopkins, A. M.; Jarrett, T. H.; Kafle, P. R.; Lange, R.; Liske, J.; Loveday, J.; Moffett, A. J.; Norberg, P.; Popescu, C. C.; Smith, M.; Taylor, E. N.; Tuffs, R. J.; Wang, L.; Wilkins, S. M.

    2016-07-01

    We present the Lambda Adaptive Multi-Band Deblending Algorithm in R (LAMBDAR), a novel code for calculating matched aperture photometry across images that are neither pixel- nor PSF-matched, using prior aperture definitions derived from high-resolution optical imaging. The development of this program is motivated by the desire for consistent photometry and uncertainties across large ranges of photometric imaging, for use in calculating spectral energy distributions. We describe the program, specifically key features required for robust determination of panchromatic photometry: propagation of apertures to images with arbitrary resolution, local background estimation, aperture normalization, uncertainty determination and propagation, and object deblending. Using simulated images, we demonstrate that the program is able to recover accurate photometric measurements in both high-resolution, low-confusion, and low-resolution, high-confusion, regimes. We apply the program to the 21-band photometric data set from the Galaxy And Mass Assembly (GAMA) Panchromatic Data Release (PDR; Driver et al. 2016), which contains imaging spanning the far-UV to the far-IR. We compare photometry derived from LAMBDAR with that presented in Driver et al. (2016), finding broad agreement between the data sets. None the less, we demonstrate that the photometry from LAMBDAR is superior to that from the GAMA PDR, as determined by a reduction in the outlier rate and intrinsic scatter of colours in the LAMBDAR data set. We similarly find a decrease in the outlier rate of stellar masses and star formation rates using LAMBDAR photometry. Finally, we note an exceptional increase in the number of UV and mid-IR sources able to be constrained, which is accompanied by a significant increase in the mid-IR colour-colour parameter-space able to be explored.

  15. The RSA survey of dwarf galaxies, 1: Optical photometry

    NASA Technical Reports Server (NTRS)

    Vader, J. Patricia; Chaboyer, Brian

    1994-01-01

    We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are

  16. Optical Photometry of the flaring gamma-ray blazar AO 0235+164

    NASA Astrophysics Data System (ADS)

    Pursimo, Tapio; Losada, Illa R.; Messa, Matteo; Gafton, Emanuel; Ojha, Roopesh

    2016-03-01

    We report optical photometry of the blazar AO 0235+164 obtained with the 2.56m Nordic Optical Telescope in La Palma to look for any enhanced optical activity associated with a recent flare in the daily averaged gamma-ray flux seen in the public lightcurve of the Fermi/LAT instrument: http://fermi.gsfc.nasa.gov/FTP/glast/data/lat/catalogs/asp/current/lightcurves/0235+164_86400.png Fermi/LAT first reported a detection of gamma-ray activity from this source in Sep, 2008 (ATel#1744) and a short timescale flare in Oct 14, 2008 (ATel#1784).

  17. Nighttime Aerosol Optical Depth Variability From Astronomical Photometry

    NASA Astrophysics Data System (ADS)

    Musat, I. C.; Ellingson, R. G.

    2006-12-01

    A technique for determination of the short-term (6 minutes intervals) variability of the aerosol optical depth (AOD) during nighttime from broadband visible measurements of star irradiances during clear nights was developed for the instrument called the Whole Sky Imager (WSI), placed at the Atmospheric Radiation Measurement (ARM) observation site in Oklahoma. The AOD is inferred indirectly from simultaneous observations of extinction of stars having different colors (spectra) and different elevations above the horizon, and takes into account the other sources for starlight attenuation in the atmosphere which might be present and which are measured by other instruments at the site at compatible timescales (e.g., precipitable water vapor content, columnar ozone amount, observed atmospheric stratification). The total error of the new method is a combination of the absolute star flux measurement error with the WSI and a systematic error in the models assumed for the other atmospheric components causing the starlight extinction. The relative error in the aerosol optical depth determined through this method is found to be below 4%. For the validation of the results, the comparison of the aerosol optical depth measured with the Lidar at 10 minutes intervals (at 355nm) with the AOD determined from WSI (in visible) shows a good agreement for the data in the interval studied (1999-2003).

  18. DEEP K{sub s} -NEAR-INFRARED SURFACE PHOTOMETRY OF 80 DWARF IRREGULAR GALAXIES IN THE LOCAL VOLUME

    SciTech Connect

    Fingerhut, Robin L.; McCall, Marshall L.; Argote, Mauricio; Cluver, Michelle E.; Nishiyama, Shogo; Rekola, Rami T. F.; Richer, Michael G.; Vaduvescu, Ovidiu; Woudt, Patrick A. E-mail: mccall@yorku.c E-mail: mcluver@ipac.caltech.ed E-mail: rareko@utu.f E-mail: ovidiuv@ing.iac.e

    2010-06-10

    We present deep near-infrared (K{sub s}) images and surface photometry for 80 dwarf irregular galaxies (dIs) within {approx}5 Mpc of the Milky Way. The galaxy images were obtained at five different facilities between 2004 and 2006. The image reductions and surface photometry have been performed using methods specifically designed for isolating faint galaxies from the high and varying near-infrared sky level. Fifty-four of the 80 dIs have surface brightness profiles which could be fit to a hyperbolic-secant (sech) function, while the remaining profiles could be fit to the sum of a sech and a Gaussian function. From these fits, we have measured central surface brightnesses, scale lengths, and integrated magnitudes. This survey is part of a larger study of the connection between large-scale structure and the global properties of dIs, the hypothesized building-blocks of more massive galaxies.

  19. Analysis of Mount St. Helens ash from optical photoelectric photometry

    NASA Technical Reports Server (NTRS)

    Cardelli, J. A.; Ackerman, T. P.

    1983-01-01

    The optical properties of suspended dust particles from the eruption of Mt. St. Helens on July 23, 1980 are investigated using photoelectric observations of standard stars obtained on the 0.76-m telescope at the University of Washington 48 hours after the eruption. Measurements were made with five broad-band filters centered at 3910, 5085, 5480, 6330, and 8050 A on stars of varying color and over a wide range of air masses. Anomalous extinction effects due to the volcanic ash were detected, and a significant change in the wavelength-dependent extinction parameter during the course of the observations was established by statistical analysis. Mean particle size (a) and column density (N) are estimated using the Mie theory, assuming a log-normal particle-size distribution: a = 0.18 micron throughout; N = 1.02 x 10 to the 9th/sq cm before 7:00 UT and 2.33 x 10 to the 9th/sq cm after 8:30 UT on July 25, 1980. The extinction is attributed to low-level, slowly migrating ash, possibly combined with products of gas-to-particle conversion and coagulation.

  20. A laboratory module on radiometry, photometry and colorimetry for an undergraduate optics course

    NASA Astrophysics Data System (ADS)

    Polak, Robert D.

    2014-07-01

    The bachelor's degree in Physics at Loyola University Chicago requires both an upper-division course in Optics as well as a companion Optics Laboratory course. Recently, the laboratory course has undergone dramatic changes. Traditional weekly laboratories have been replaced with three laboratory modules, where students focus on a single topic over several weeks after which the students submit a laboratory report written in the style of a journal article following American Institute of Physics style manual. With this method, students are able to gain a deeper understanding of the specific topic areas of radiometry, photometry and colorimetry, lens design and aberrations, and polarization and interference while using industry-standard equipment and simulation software. In particular, this work will provide the details of the laboratory module on radiometry, photometry and colorimetry where students use a photoradiometer and integrating sphere to characterize the optical properties of an LCD monitor, light bulb and a fiber optic light source calculating properties such as luminous flux, luminous intensity, luminance, CIE color coordinates, NTSC ratio, color temperature and luminous efficacy.

  1. Deep space optical communication via relay satellite

    NASA Technical Reports Server (NTRS)

    Dolinar, S.; Vilnrotter, V.; Gagliardi, R.

    1981-01-01

    The application of optical communications for a deep space link via an earth-orbiting relay satellite is discussed. The system uses optical frequencies for the free-space channel and RF links for atmospheric transmission. The relay satellite is in geostationary orbit and contains the optics necessary for data processing and formatting. It returns the data to earth through the RF terrestrial link and also transmits an optical beacon to the satellite for spacecraft return pointing and for the alignment of the transmitting optics. Future work will turn to modulation and coding, pointing and tracking, and optical-RF interfacing.

  2. High-Resolution Spectroscopy and Optical Photometry of MWC 349A and MWC 349B

    NASA Astrophysics Data System (ADS)

    Manset, N.; Miroshnichenko, A. S.; Zharikov, S. V.; Kusakin, A. V.

    2017-02-01

    MWC 349A is a V ˜ 13 mag object with the B[e] phenomenon, a very strong optical emission-line spectrum, maser and laser line emission, and a radio-bright bipolar nebula, attenuated by ˜10 mag of interstellar extinction. MWC 349B is a visual companion of MWC 349A with no previously reported signs of emission. The physical connection of the pair has been the subject of debates toward revealing the evolutionary state of MWC 349A. Only low-resolution spectra reported for MWC 349B resulted in estimating its parameters with a large uncertainty. We report the results of high-resolution optical spectroscopy of both objects as well as their optical photometry.

  3. Small diameter, deep bore optical inspection system

    DOEpatents

    Lord, David E.; Petrini, Richard R.; Carter, Gary W.

    1981-01-01

    An improved rod optic system for inspecting small diameter, deep bores. The system consists of a rod optic system utilizing a curved mirror at the end of the rod lens such that the optical path through the system is bent 90.degree. to minimize optical distortion in examining the sides of a curved bore. The system is particularly useful in the examination of small bores for corrosion, and is capable of examining 1/16 inch diameter and up to 4 inch deep drill holes, for example. The positioning of the curved mirror allows simultaneous viewing from shallow and right angle points of observation of the same artifact (such as corrosion) in the bore hole. The improved rod optic system may be used for direct eye sighting, or in combination with a still camera or a low-light television monitor; particularly low-light color television.

  4. Small diameter, deep bore optical inspection system

    DOEpatents

    Lord, D.E.; Petrini, R.R.; Carter, G.W.

    An improved rod optic system for inspecting small diameter, deep bores is described. The system consists of a rod optic system utilizing a curved mirror at the end of the rod lens such that the optical path through the system is bent 90/sup 0/ to minimize optical distortion in examing the sides of a curved bore. The system is particularly useful in the examination of small bores for corrosion, and is capable if examing 1/16 inch diameter and up to 4-inch deep drill holes, for example. The positioning of the curved mirror allows simultaneous viewing from shallow and righ angle points of observation of the same artifact (such as corrosion) in the bore hole. The improved rod optic system may be used for direct eye sighting, or in combination with a still camera or a low-light television monitor; particularly low-light color television.

  5. Time-Resolved CubeSat Photometry with a Low Cost Electro-Optics System

    NASA Astrophysics Data System (ADS)

    Gasdia, F.; Barjatya, A.; Bilardi, S.

    2016-09-01

    Once the orbits of small debris or CubeSats are determined, optical rate-track follow-up observations can provide information for characterization or identification of these objects. Using the Celestron 11" RASA telescope and an inexpensive CMOS machine vision camera, we have obtained time-series photometry from dozens of passes of small satellites and CubeSats over sites in Florida and Massachusetts. The fast readout time of the CMOS detector allows temporally resolved sampling of glints from small wire antennae and structural facets of rapidly tumbling objects. Because the shape of most CubeSats is known, these light curves can be used in a mission support function for small satellite operators to diagnose or verify the proper functioning of an attitude control system or deployed antenna or instrument. We call this telescope system and the accompanying analysis tools OSCOM for Optical tracking and Spectral characterization of CubeSats for Operational Missions. We introduce the capability of OSCOM for space object characterization, and present photometric observations demonstrating the potential of high frame rate small satellite photometry.

  6. Optical deep space communication via relay satellite

    NASA Technical Reports Server (NTRS)

    Gagliardi, R. M.; Vilnrotter, V. A.; Dolinar, S. J., Jr.

    1981-01-01

    The possible use of an optical for high rate data transmission from a deep space vehicle to an Earth-orbiting relay satellite while RF links are envisioned for the relay to Earth link was studied. A preliminary link analysis is presented for initial sizing of optical components and power levels, in terms of achievable data rates and feasible range distances. Modulation formats are restricted to pulsed laser operation, involving bot coded and uncoded schemes. The advantage of an optical link over present RF deep space link capabilities is shown. The problems of acquisition, pointing and tracking with narrow optical beams are presented and discussed. Mathematical models of beam trackers are derived, aiding in the design of such systems for minimizing beam pointing errors. The expected orbital geometry between spacecraft and relay satellite, and its impact on beam pointing dynamics are discussed.

  7. Gallium arsenide deep-level optical emitter for fibre optics.

    PubMed

    Pan, Janet L; McManis, Joseph E; Osadchy, Thomas; Grober, Louise; Woodall, Jerry M; Kindlmann, Peter J

    2003-06-01

    Fibre-optic components fabricated on the same substrate as integrated circuits are important for future high-speed communications. One industry response has been the costly push to develop indium phosphide (InP) electronics. However, for fabrication simplicity, reliability and cost, gallium arsenide (GaAs) remains the established technology for integrated optoelectronics. Unfortunately, the GaAs bandgap wavelength (0.85 microm) is far too short for fibre optics at 1.3-1.5 microm. This has led to work on materials that have a large lattice mismatch on GaAs. Here we demonstrate the first light-emitting diode (LED) that emits at 1.5 microm fibre-optic wavelengths in GaAs using optical transitions from arsenic antisite (As(Ga)) deep levels. This is an enabling technology for fibre-optic components that are lattice-matched to GaAs integrated circuits. We present experimental results showing significant internal optical power (24 mW) and speed (in terahertz) from GaAs optical emitters using deep-level transitions. Finally, we present theory showing the ultimate limit to the efficiency-bandwidth product of semiconductor deep-level optical emitters.

  8. Broad-Band Optical Photometry of the LMXB PSR J1023+0038

    NASA Astrophysics Data System (ADS)

    Gonzalez, Emmanuel; Mason, P. A.; Robinson, E. L.

    2013-01-01

    Optical observations of the low-mass X-ray binary PSR J1023+0038 are presented. CCD photometry was collected with 10s integrations using the Argos camera on the 2.1 m Otto Struve Telescope of McDonald Observatory. Data was obtained during seven nights in February 2011 and January 2012. The light curves are quite similar to those obtained in previous studies, allowing a systematic period study of new data combined with three epochs of published light curves, covering a span of 8 years. An unambiguous period of 0.1980962(4) days is derived. An O-C diagram of the residuals is constructed and does not clearly require a significant period change.

  9. VizieR Online Data Catalog: Optical and UV photometry of SN 2013dy (Zhai+, 2016)

    NASA Astrophysics Data System (ADS)

    Zhai, Q.; Zhang, J.-J.; Wang, X.-F.; Zhang, T.-M.; Liu, Z.-W.; Brown, P. J.; Huang, F.; Zhao, X.-L.; Chang, L.; Yi, W.-M.; Wang, C.-J.; Xin, Y.-X.; Wang, J.-G.; Lun, B.-L.; Zhang, X.-L.; Fan, Y.-F.; Zheng, X.-M.; Bai, J.-M.

    2016-08-01

    SN2013dy, an Type Ia supernova (SNIa), was discovered at roughly a magnitude of ~17.2mag on UT July 10.45 2013 (Universal Time) in an unfiltered image of the galaxy NGC7250 by the Lick observatory supernova search (Casper et al., 2013CBET.3588....1C). Our first observation of SN 2013dy is in spectroscopy on 2013 July 14 (Zhang & Wang 2013CBET.3394....1Z; 4.76days after the first light and published in Zheng et al. 2013ApJ...778L..15Z) with the Yunnan Faint Object Spectrograph and Camera (YFOSC) mounted at the Li-Jiang 2.4m Telescope (LJT) of Yunnan Observatories (YNAO), China. About two weeks later, we started to monitor this transient intensively at LJT in both ground-based UBVRI photometry and spectroscopy spanning from t~+0 to t~+180days. Ten local standard stars (see Table1 in the paper) in the field of SN2013dy are used to transform the instrumental magnitudes of SN2013dy to the standard Johnson UBV and Kron-Cousins RI system, as listed in Table2. Optical photometry data are also collected with the Tsinghua-NAOC 0.8m telescope (TNT) at Xing-Long Observation of National Astronomical Observatories (NAOC), China, from t~-2days to t~+150days. Additionally, three spectra were obtained at the Xing-Long 2.16 m telescope (hereafter XLT) with the Bei-Jing Faint Object Spectrograph and Camera (BFOSC). Furthermore, this target was also observed by the Ultra-Violet/Optical Telescope (UVOT) on board the Swift satellite. The Swift observatory began observing SN 2013dy on 2013 July 17.09, about 10days (t~-10days) before the B band maximum, and continued for approximately 26days (t~+15days). These photometric observations are performed in three UV filters (uvw2, uvm2, and uvw1) and three broadband optical filters (uu, bb, and vv). Table3 lists the final UVOT UV/optical magnitudes of SN2013dy. (2 data files).

  10. DeepSurveyCam--A Deep Ocean Optical Mapping System.

    PubMed

    Kwasnitschka, Tom; Köser, Kevin; Sticklus, Jan; Rothenbeck, Marcel; Weiß, Tim; Wenzlaff, Emanuel; Schoening, Timm; Triebe, Lars; Steinführer, Anja; Devey, Colin; Greinert, Jens

    2016-01-28

    Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor.

  11. DeepSurveyCam—A Deep Ocean Optical Mapping System

    PubMed Central

    Kwasnitschka, Tom; Köser, Kevin; Sticklus, Jan; Rothenbeck, Marcel; Weiß, Tim; Wenzlaff, Emanuel; Schoening, Timm; Triebe, Lars; Steinführer, Anja; Devey, Colin; Greinert, Jens

    2016-01-01

    Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor. PMID:26828495

  12. Deep space optical communications development program

    NASA Technical Reports Server (NTRS)

    Lesh, James R.

    1987-01-01

    The technology development, spacecraft systems impact, design examples and overall development plan for optical deep space communications are described. Design examples include moderate distance links like ones from Mars to Earth, out through a potential mission to a distance of 1000 A.U. The technology development plan, which includes both ground-based as well as Earth orbit-based reception considerations, spans the period from 1985 to the year 2003. Past technology developments in high efficiency lasers, optical modulation and coding, and high power efficiency communications techniques at multiple bits of information per detected photon are also discussed.

  13. EDGES: Deep Multi-Wavelength Photometry and Radial SED Analysis for UGC8303 and UGC8320

    NASA Astrophysics Data System (ADS)

    Phenicie, Christopher; Dale, Daniel A.; Barnes, Kate L.; Beltz-Mohrmann, Gillian; Egan, Arika; Hatlestad, Alan; Herzog, Laura; Kobulnicky, Henry A.; Leung, Andrew S.; McLane, Jacob; Roberts, Jareth; Staudaher, Shawn; van Zee, Liese

    2015-01-01

    New deep ugr imaging was obtained on the Wyoming Infrared Observatory 2.3 meter telescope for UGC8303 and UGC8320, two galaxies in the Extended Disk Galaxy Exploration Science survey. These data are coupled with deep GALEX ultraviolet and Spitzer infrared imaging to study the radial variations in the spectral energy distributions. Results from the CIGALE SED modeling software will be presented, including trends in the galaxy star formation histories. This work is supported by the National Science Foundation under REU grant AST 1063146.

  14. EDGES: Deep Multi-Wavelength Photometry and Radial SED Analysis for Six Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Mclane, Jacob Noel; Leung, Andrew S.; Dale, Daniel A.; Barnes, Kate L.; Beltz-Mohrmann, Gillian; Egan, Arika; Hatlestad, Alan; Herzog, Laura; Kobulnicky, Henry A.; Phenicie, Christopher; Roberts, Jareth; Staudaher, Shawn; van Zee, Liese

    2015-01-01

    New deep ugr imaging was obtained on the Wyoming Infrared Observatory 2.3 meter telescope for NGC4220, NGC4618, NGC5055, NGC5523 and NGC5608, five galaxies in the Extended Disk Galaxy Exploration Science Survey (EDGES). Additional imaging was obtained for NGC4625, a non-EDGES target of opportunity. These data are coupled with deep GALEX ultraviolet and Spitzer/WISE infrared imaging to study the radial variations in the spectral energy distributions. Results from the CIGALE SED modeling software will be presented, including trends in the galaxy star formation histories. This work is supported by the National Science Foundation under REU grant AST 1063146.

  15. EDGES: Deep Multi-Wavelength Photometry and Radial SED Analysis for NGC4242 and UGC7301

    NASA Astrophysics Data System (ADS)

    Egan, Arika; Dale, Daniel A.; Barnes, Kate L.; Beltz-Mohrmann, Gillian; Hatlestad, Alan; Herzog, Laura; Kobulnicky, Henry A.; Leung, Andrew S.; McLane, Jacob; Phenicie, Christopher; Roberts, Jareth; Staudaher, Shawn; van Zee, Liese

    2015-01-01

    New deep ugr imaging was obtained on the Wyoming Infrared Observatory 2.3 meter telescope for NGC4242 and UGC7301, two galaxies in the Extended Disk Galaxy Exploration Science survey. These data are coupled with deep GALEX ultraviolet and Spitzer/WISE infrared imaging to study the radial variations in the spectral energy distributions. Results from the CIGALE SED modeling software will be presented, including trends in the galaxy star formation histories. This work is supported by the National Science Foundation under REU grant AST 1063146.

  16. EDGES: Deep Multi-Wavelength Photometry and Radial SED Analysis for NGC4707 and NGC5229

    NASA Astrophysics Data System (ADS)

    Herzog, Laura; Dale, Daniel A.; Barnes, Kate L.; Beltz-Mohrmann, Gillian; Egan, Arika; Hatlestad, Alan; Kobulnicky, Henry A.; Leung, Andrew S.; McLane, Jacob; Phenicie, Christopher; Roberts, Jareth; Staudaher, Shawn; van Zee, Liese

    2015-01-01

    New deep ugr imaging was obtained on the Wyoming Infrared Observatory 2.3 meter telescope for NGC4707 and NGC5229, two galaxies in the Extended Disk Galaxy Exploration Science survey. These data are coupled with deep GALEX ultraviolet and Spitzer infrared imaging to study the radial variations in the spectral energy distributions. Results from the CIGALE SED modeling software will be presented, including trends in the galaxy star formation histories. This work is supported by the National Science Foundation under REU grant AST 1063146.

  17. Deep Photometry of Galaxies in the VEGAS Survey: The Case of NGC 4472

    NASA Astrophysics Data System (ADS)

    Spavone, M.

    The VST-VEGAS project is aimed at observing and studying a rich sample of nearby early-type galaxies in order to systematically characterize their properties over a wide baseline of sizes and out to the faint outskirts where data are rather scarce so far. The external regions of galaxies more easily retain signatures about the formation and evolution mechanisms which shaped them, as their relaxation time are longer, and they are more weakly influenced by processes such as mergers, secular evolution, central black hole activity, and supernova feedback on the ISM, which tend to level age and metallicity gradients. The collection of a wide photometric dataset of a large number of galaxies in various environmental conditions, may help to shed light on these questions. To this end VEGAS exploits the potential of the VLT Survey Telescope (VST) which provides high quality images of 1 deg2 field of view in order to satisfy both the requirement of high resolution data and the need of studying nearby, and thus large, objects. We present a detailed study of the surface photometry of the elliptical galaxy NGC4472 and of smaller ETGs in its field, performed by using new g and i bands images to constrain the formation history of this nearby giant galaxy, and to investigate the presence of very faint substructures in its surroundings.

  18. Deep Stromvil Photometry for Star Formation in the Head of the Pelican Nebula

    NASA Astrophysics Data System (ADS)

    Boyle, Richard P.; J., S.; Stott, J.; J., S.; Janusz, R.; J., S.; Straizys, V.

    2010-01-01

    The North America and Pelican Nebulae, and specifically the dark cloud L935 contain regions of active star formation (Herbig, G. H. 1958, ApJ, 128,259). Previously we reported on Vatican telescope observations by Stromvil intermediate-band filters in a 12-arcmin field in the "Gulf of Mexico" region of L935. There we classify A, F, and G-type stars. However, the many faint K and M-type dwarf stars remain somewhat ambiguous in calibration and classification. But attaining reasonable progress, we turn to another part of L935 located near the Pelican head. This area includes the "bright rim" which is formed by dust and gas condensed by the light pressure of an unseen O-type star hidden behind the dense dark cloud. Straizys and Laugalys (2008 Baltic Astronomy, 17, 143 ) have identified this star to be one of the 2MASS objects with Av=23 mag. A few concentrations of faint stars, V 13 to 14 mag. are immersed in this dark region. Among these stars are a few known emission-line objects (T-Tauri or post T-Tauri stars). A half degree nearby are some photometric Vilnius standards we use to calibrate our new field. We call on 2MASS data for correlative information. Also the Stromvil photometry offers candidate stars for spectral observations. The aim of this study in the Vilnius and Stromvil photometric systems is to classify stars down to V = 18 mag., to confirm the existence of the young star clusters, and to determine the distance of the cloud covering the suspected hidden ionizing star.

  19. Deep Space 1 photometry of the nucleus of Comet P/19 Borrelly

    NASA Technical Reports Server (NTRS)

    Buratti, B. J.; Britt, D.; Oberst, J.; Soderblom, L. A.; Hillier, J. K.; Hicks, M. D.

    2002-01-01

    The NASA-JPL Deep Space 1 Mission (DS1) encountered the short-period Jupiter-family comet 19/P Borrelly on September 22, 2001, about 8 days after perihelion. DS1's payload contained a remote-sensing package that included a 1024 square CCD and a near IR spectrometer with 12nm resolution. Prior to its closest approach, the remote-sensing package on the spacecraft obtained 25 CCD images of the comet and 45 near-IR spectra.

  20. CANDELS Multiwavelength Catalogs: Source Identification and Photometry in the CANDELS UKIDSS Ultra-deep Survey Field

    NASA Astrophysics Data System (ADS)

    Galametz, Audrey; Grazian, Andrea; Fontana, Adriano; Ferguson, Henry C.; Ashby, M. L. N.; Barro, Guillermo; Castellano, Marco; Dahlen, Tomas; Donley, Jennifer L.; Faber, Sandy M.; Grogin, Norman; Guo, Yicheng; Huang, Kuang-Han; Kocevski, Dale D.; Koekemoer, Anton M.; Lee, Kyoung-Soo; McGrath, Elizabeth J.; Peth, Michael; Willner, S. P.; Almaini, Omar; Cooper, Michael; Cooray, Asantha; Conselice, Christopher J.; Dickinson, Mark; Dunlop, James S.; Fazio, G. G.; Foucaud, Sebastien; Gardner, Jonathan P.; Giavalisco, Mauro; Hathi, N. P.; Hartley, Will G.; Koo, David C.; Lai, Kamson; de Mello, Duilia F.; McLure, Ross J.; Lucas, Ray A.; Paris, Diego; Pentericci, Laura; Santini, Paola; Simpson, Chris; Sommariva, Veronica; Targett, Thomas; Weiner, Benjamin J.; Wuyts, Stijn; the CANDELS Team

    2013-06-01

    We present the multiwavelength—ultraviolet to mid-infrared—catalog of the UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra-Deep Survey field observed as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). Based on publicly available data, the catalog includes the CANDELS data from the Hubble Space Telescope (near-infrared WFC3 F125W and F160W data and visible ACS F606W and F814W data); u-band data from CFHT/Megacam; B, V, Rc , i', and z' band data from Subaru/Suprime-Cam; Y and Ks band data from VLT/HAWK-I; J, H, and K band data from UKIDSS (Data Release 8); and Spitzer/IRAC data (3.6, 4.5 μm from SEDS; 5.8 and 8.0 μm from SpUDS). The present catalog is F160W-selected and contains 35, 932 sources over an area of 201.7 arcmin2 and includes radio- and X-ray-detected sources and spectroscopic redshifts available for 210 sources.

  1. CANDELS MULTIWAVELENGTH CATALOGS: SOURCE IDENTIFICATION AND PHOTOMETRY IN THE CANDELS UKIDSS ULTRA-DEEP SURVEY FIELD

    SciTech Connect

    Galametz, Audrey; Grazian, Andrea; Fontana, Adriano; Castellano, Marco; Ferguson, Henry C.; Dahlen, Tomas; Grogin, Norman; Huang, Kuang-Han; Koekemoer, Anton M.; Ashby, M. L. N.; Willner, S. P.; Barro, Guillermo; Faber, Sandy M.; Guo, Yicheng; Kocevski, Dale D.; Lee, Kyoung-Soo; McGrath, Elizabeth J.; Peth, Michael; Almaini, Omar; Collaboration: CANDELS team; and others

    2013-06-01

    We present the multiwavelength-ultraviolet to mid-infrared-catalog of the UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra-Deep Survey field observed as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). Based on publicly available data, the catalog includes the CANDELS data from the Hubble Space Telescope (near-infrared WFC3 F125W and F160W data and visible ACS F606W and F814W data); u-band data from CFHT/Megacam; B, V, R{sub c} , i', and z' band data from Subaru/Suprime-Cam; Y and K{sub s} band data from VLT/HAWK-I; J, H, and K band data from UKIDSS (Data Release 8); and Spitzer/IRAC data (3.6, 4.5 {mu}m from SEDS; 5.8 and 8.0 {mu}m from SpUDS). The present catalog is F160W-selected and contains 35, 932 sources over an area of 201.7 arcmin{sup 2} and includes radio- and X-ray-detected sources and spectroscopic redshifts available for 210 sources.

  2. Deep HST/ACS Photometry of an Arc of Young Stars in the Southern Halo of M82

    NASA Astrophysics Data System (ADS)

    Suwannajak, Chutipong

    2016-01-01

    We present deep HST/ACS photometry of an arclike, overdense region of stars in the southern halo of M82, located approximately 5 kpc from its disk. This arc feature was originally identified about a decade ago. The early ground-based studies suggested that it contains young stars with ages and metallicities similar to those that formed in the tidal tails between M81, M82, and NGC3077 during their interactions. The arc is clearly presented in the spatial distribution of stars in our field with significantly higher stellar density than the background M82 halo stars. The location of the tip of the red giant branch (RGB) reveals the arc to have a similar distance to M81 and M82, therefore confirming that it belongs to this interacting system. Combining our data with those from the ACS Nearby Galaxy Survey Treasury (ANGST), we construct a color-magnitude diagram (CMD) for the arc. A sequence of young stars is clearly presented on its CMD. This young main sequence is not seen in other parts of the M82 halo. Single-metallicity isochrones are used to derive the age of the young stars in the arc. We confirm that these stars exhibit ages consistent with young stars found in the HI bridges between M81, M82 and NGC3077. Furthermore, the mean metallicity of the RGB stars is also derived from their metallicity distribution function and found to be similar to that found in the HI bridges.

  3. Reliability of Heterochromatic Flicker Photometry in Measuring Macular Pigment Optical Density among Preadolescent Children.

    PubMed

    McCorkle, Sasha M; Raine, Lauren B; Hammond, Billy R; Renzi-Hammond, Lisa; Hillman, Charles H; Khan, Naiman A

    2015-10-16

    Macular pigment optical density (MPOD)-assessed using customized heterochromatic flicker photometry (cHFP)-is related to better cognition and brain lutein among adults. However, the reliability of MPOD assessed by cHFP has not been investigated in children. We assessed inter-session reliability of MPOD using modified cHFP. 7-10-year-olds (n = 66) underwent cHFP over 2 visits using 11 examiners. Reliability was also assessed in a subsample (n = 46) with only 2 examiners. Among all participants, there was no significant difference between the two sessions (p = 0.59-session 1: 0.61 ± 0.28; session 2: 0.62 ± 0.27). There was no significant difference in the MPOD of boys vs. girls (p = 0.56). There was a significant correlation between sessions (Y = 0.52x + 0.31; R² = 0.29, p ≤ 0.005), with a reliability of 0.70 (Cronbach's α). Among the subsample with 2 examiners, there was a significant correlation between sessions (Y = 0.54x + 0.31; R² = 0.32, p < 0.005), with a reliability of 0.72 (Cronbach's α). In conclusion, there is moderate reliability for modified cHFP to measure MPOD in preadolescents. These findings provide support for future studies aiming to conduct noninvasive assessments of retinal xanthophylls and study their association with cognition during childhood.

  4. Ozone monitoring using differential optical absorption spectroscopy (DOAS) and UV photometry instruments in Sohar, Oman.

    PubMed

    Nawahda, Amin

    2015-08-01

    Ground level ozone (O3) concentrations were measured across Sohar highway in Oman during a four-month period from September to December 2014 by using an open-path deferential optical absorption spectroscopy (DOAS) instrument. The monthly average concentrations of O3 varied from 19.6 to 29.4 ppb. The measurements of O3 are compared with the measurements of a non-open-path UV photometry analyzer (UVP). The percent difference (PD) concept and linear regression methods were used to compare the readings of the two instruments. The findings show high correlation coefficients between the measurements of the DOAS and UVP instruments. The DOAS measurements of O3 are found to be less than those measured by the UVP instrument; the correlation coefficients between absolute PD values and meteorological parameters and PM2.5 were very low indicating a minor effect; therefore, titrations of O3 by traffic emissions and difference in elevation could be the reason for the difference in the measurements of the two instruments.

  5. Deep HST Photometry of NGC 6388: Age and Horizontal Branch Luminosity

    NASA Technical Reports Server (NTRS)

    Stetson, Peter B.; Catelan, M.; Pritzl, Barton J.; Smith, Horace A.; Kinemuchi, Karen; Layden, Andrew C.; Sweigart, Allen V.; Rich, R. M.

    2006-01-01

    We present the first deep color-magnitude diagram (CMD) of the Galactic globular cluster NGC 6388, obtained with the Hubble Space Telescope, that is able to reach the main-sequence turnoff point of the cluster. From a detailed comparison between the cluster CMD and that of 47 Tucanae (NGC 104), we find that the bulk of the stars in these two clusters have nearly the same age and chemical composition. On the other hand, our results indicate that the blue horizontal branch and RR Lyrae components in NGC 6388 are intrinsically over-luminous, which must be due to one or more, still undetermined, non-canonical second parameter(s) affecting a relatively minor fraction of the stars in NGC 6388.

  6. Autonomous Deep-Space Optical Navigation Project

    NASA Technical Reports Server (NTRS)

    D'Souza, Christopher

    2014-01-01

    This project will advance the Autonomous Deep-space navigation capability applied to Autonomous Rendezvous and Docking (AR&D) Guidance, Navigation and Control (GNC) system by testing it on hardware, particularly in a flight processor, with a goal of limited testing in the Integrated Power, Avionics and Software (IPAS) with the ARCM (Asteroid Retrieval Crewed Mission) DRO (Distant Retrograde Orbit) Autonomous Rendezvous and Docking (AR&D) scenario. The technology, which will be harnessed, is called 'optical flow', also known as 'visual odometry'. It is being matured in the automotive and SLAM (Simultaneous Localization and Mapping) applications but has yet to be applied to spacecraft navigation. In light of the tremendous potential of this technique, we believe that NASA needs to design a optical navigation architecture that will use this technique. It is flexible enough to be applicable to navigating around planetary bodies, such as asteroids.

  7. Multi-colour optical photometry of V404 Cygni in outburst

    NASA Astrophysics Data System (ADS)

    Martí, Josep; Luque-Escamilla, Pedro L.; García-Hernández, María T.

    2016-02-01

    Context. This observational paper has been prepared in the context of the large multi-wavelength effort by many observers with the aim of following up the transient flaring event of V404 Cygni that took place for several weeks in 2015 June. Aims: Our main original aim was to contribute to the study of this transient source by acquiring broad-band photometric observations during its most active flaring phases. Nevertheless, after a detailed analysis of the data, several interesting results were obtained that encouraged a dedicated publication. Methods: The methodology used was based on broad-band differential CCD photometry. This outburst of V404 Cygni rendered the source a very bright target easily within reach of small educational telescopes. Therefore, the 41 cm telescope available at the Astronomical Observatory of the University of Jaén was used in this work. Results: We detected variability at different time scales, both in amplitude and colour. Individual optical flares appear every half hour on average during our 3 h long observation, although large-amplitude (~1 mag) variations are also observed to occur on intervals as short as 10 min. Also, colour variations appear to be highly correlated in a colour-colour diagram. Another remarkable finding is the detection of time lag, from about one to a fraction of a minute between light curves in different filters (VRcIc). Conclusions: The observed behaviour is tentatively interpreted in an scenario based on the ejection of non-thermal emitting, relativistic plasmons, with their synchrotron spectra extending up to optical wavelengths. This would render some of the V404 Cygni flares very similar to those of the well-know microquasar GRS 1915+105

  8. THE HIGH A{sub V} Quasar Survey: Reddened Quasi-Stellar Objects selected from optical/near-infrared photometry. II

    SciTech Connect

    Krogager, J.-K.; Fynbo, J. P. U.; Vestergaard, M.; Geier, S.; Venemans, B. P.; Ledoux, C.; Møller, P.; Noterdaeme, P.; Kangas, T.; Pursimo, T.; Smirnova, O.; Saturni, F. G.

    2015-03-15

    Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared (near-IR) color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared Survey Explorer. In our sample of 159 candidates, 154 (97%) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify nine such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems toward 30 QSOs, 2 of which are consistent with the best-fit absorber redshift from the statistical modeling. Furthermore, we observe a broad range in SED properties of the QSOs as probed by the rest-frame 2 μm flux. We find QSOs with a strong excess as well as QSOs with a large deficit at rest-frame 2 μm relative to a QSO template. Potential solutions to these discrepancies are discussed. Overall, our study demonstrates the high efficiency of the optical/near-IR selection of red QSOs.

  9. Daytime adaptive optics for deep space optical communications

    NASA Technical Reports Server (NTRS)

    Wilson, Keith; Troy, M.; Srinivasan, M.; Platt, B.; Vilnrotter, V.; Wright, M.; Garkanian, V.; Hemmati, H.

    2003-01-01

    The deep space optical communications subsystem offers a higher bandwidth communications link in smaller size, lower mass, and lower power consumption subsystem than does RF. To demonstrate the benefit of this technology to deep space communications NASA plans to launch an optical telecommunications package on the 2009 Mars Telecommunications orbiter spacecraft. Current performance goals are 30-Mbps from opposition, and 1-Mbps near conjunction (-3 degrees Sun-Earth-Probe angle). Yet, near conjunction the background noise from the day sky will degrade the performance of the optical link. Spectral and spatial filtering and higher modulation formats can mitigate the effects of background sky. Narrowband spectral filters can result in loss of link margin, and higher modulation formats require higher transmitted peak powers. In contrast, spatial filtering at the receiver has the potential of being lossless while providing the required sky background rejection. Adaptive optics techniques can correct wave front aberrations caused by atmospheric turbulence and enable near-diffraction-limited performance of the receiving telescope. Such performance facilitates spatial filtering, and allows the receiver field-of-view and hence the noise from the sky background to be reduced.

  10. Reliability of Heterochromatic Flicker Photometry in Measuring Macular Pigment Optical Density among Preadolescent Children

    PubMed Central

    McCorkle, Sasha M.; Raine, Lauren B.; Hammond, Billy R.; Renzi-Hammond, Lisa; Hillman, Charles H.; Khan, Naiman A.

    2015-01-01

    Macular pigment optical density (MPOD)—assessed using customized heterochromatic flicker photometry (cHFP)—is related to better cognition and brain lutein among adults. However, the reliability of MPOD assessed by cHFP has not been investigated in children. We assessed inter-session reliability of MPOD using modified cHFP. 7–10-year-olds (n = 66) underwent cHFP over 2 visits using 11 examiners. Reliability was also assessed in a subsample (n = 46) with only 2 examiners. Among all participants, there was no significant difference between the two sessions (p = 0.59—session 1: 0.61 ± 0.28; session 2: 0.62 ± 0.27). There was no significant difference in the MPOD of boys vs. girls (p = 0.56). There was a significant correlation between sessions (Y = 0.52x + 0.31; R2 = 0.29, p ≤ 0.005), with a reliability of 0.70 (Cronbach’s α). Among the subsample with 2 examiners, there was a significant correlation between sessions (Y = 0.54x + 0.31; R2 = 0.32, p < 0.005), with a reliability of 0.72 (Cronbach’s α). In conclusion, there is moderate reliability for modified cHFP to measure MPOD in preadolescents. These findings provide support for future studies aiming to conduct noninvasive assessments of retinal xanthophylls and study their association with cognition during childhood. PMID:28231224

  11. Optical Photometry of the New Optical Transient SN 2010da in NGC 300

    NASA Astrophysics Data System (ADS)

    Bond, Howard E.

    2010-05-01

    Multicolor images of the new optical transient in NGC 300, discovered by B. Monard (CBET #2289 and private communication), were obtained on 2010 May 25.37 by J. Espinoza with the SMARTS 1.3m telescope at Cerro Tololo and the ANDICAM camera. The transient has received the designation SN 2010da, although spectroscopic observations and the low luminosity suggest that it is most probably an LBV-like outburst on a dust-enshrouded massive star and not a true supernova (e.g., ATEL #2632, #2633, #2636, #2637, #2638).

  12. On the RR Lyrae Stars in Globulars. IV. ω Centauri Optical UBVRI Photometry

    NASA Astrophysics Data System (ADS)

    Braga, V. F.; Stetson, P. B.; Bono, G.; Dall'Ora, M.; Ferraro, I.; Fiorentino, G.; Freyhammer, L. M.; Iannicola, G.; Marengo, M.; Neeley, J.; Valenti, E.; Buonanno, R.; Calamida, A.; Castellani, M.; da Silva, R.; Degl'Innocenti, S.; Di Cecco, A.; Fabrizio, M.; Freedman, W. L.; Giuffrida, G.; Lub, J.; Madore, B. F.; Marconi, M.; Marinoni, S.; Matsunaga, N.; Monelli, M.; Persson, S. E.; Piersimoni, A. M.; Pietrinferni, A.; Prada-Moroni, P.; Pulone, L.; Stellingwerf, R.; Tognelli, E.; Walker, A. R.

    2016-12-01

    New accurate and homogeneous optical UBVRI photometry has been obtained for variable stars in the Galactic globular cluster ω Cen (NGC 5139). We secured 8202 CCD images covering a time interval of 24 years and a sky area of 84 × 48 arcmin. The current data were complemented with data available in the literature and provided new, homogeneous pulsation parameters (mean magnitudes, luminosity amplitudes, periods) for 187 candidate ω Cen RR Lyrae (RRLs). Among them we have 101 RRc (first overtone) and 85 RRab (fundamental) variables, and a single candidate RRd (double-mode) variable. Candidate Blazhko RRLs show periods and colors that are intermediate between the RRc and RRab variables, suggesting that they are transitional objects. A comparison of the period distribution and the Bailey diagram indicates that RRLs in ω Cen show a long-period tail not present in typical Oosterhoff II (OoII) globulars. The RRLs in dwarf spheroidals and in ultra-faint dwarfs have properties between Oosterhoff intermediate and OoII clusters. Metallicity plays a key role in shaping the above evidence. These findings do not support the hypothesis that ω Cen is the core remnant of a spoiled dwarf galaxy. Using optical period-Wesenheit relations that are reddening-free and minimally dependent on metallicity we find a mean distance to ω Cen of 13.71 ± 0.08 ± 0.01 mag (semi-empirical and theoretical calibrations). Finally, we invert the I-band period-luminosity-metallicity relation to estimate individual RRLs’ metal abundances. The metallicity distribution agrees quite well with spectroscopic and photometric metallicity estimates available in the literature. Based in part on proprietary data and on data obtained from the ESO Science Archive Facility under multiple requests by the authors; and in part upon data distributed by the NOAO Science Archive. NOAO is operated by the Association of Universities for Research in Astronomy (AURA) under cooperative agreement with the National

  13. Highlights from the Center for Adaptive Optics Treasury Survey of Distant Galaxies, Including H-band Photometry of a z=1.3 Supernova

    NASA Astrophysics Data System (ADS)

    Melbourne, J.; Barczys, M.; Wright, S. A.; Max, C. E.; Larkin, J.; Koo, D. C.; Perlmutter, S.; Steinbring, E.; Metevier, A.; Chun, M.

    2005-12-01

    The Center for Adaptive Optics Treasury Survey (CATS) is observing the deep HST galaxy fields (e.g., GOODS-N and S, COSMOS, GEMS, and EGS) with high-resolution near-infrared imaging from ground-based adaptive optics on large telescopes. Initial results from the first ten Keck laser guide star pointings are presented. Highlights include, 1) H-band (rest-frame R) photometry over maximum of a z=1.32 Type Ia supernova from the HST cluster supernova search of Perlmutter et al. (see poster of Dawson et al.); 2) a near-infrared study of small bulges of distant disk galaxies (z ˜0.6); 3) Stellar population synthesis models of AGN cores to z=1; and 4) Detection of lensed arcs around a z=0.20 cluster. CATS plans its first public data release in Fall 2006. This work is funded by the NSF Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under the cooperative agreement No. AST-9876783.

  14. Optical ground station site diversity for Deep Space Optical Communications the Mars Telecom Orbiter optical link

    NASA Technical Reports Server (NTRS)

    Wilson, K.; Parvin, B.; Fugate, R.; Kervin, P.; Zingales, S.

    2003-01-01

    Future NASA deep space missions will fly advanced high resolution imaging instruments that will require high bandwidth links to return the huge data volumes generated by these instruments. Optical communications is a key technology for returning these large data volumes from deep space probes. Yet to cost effectively realize the high bandwidth potential of the optical link will require deployment of ground receivers in diverse locations to provide high link availability. A recent analysis of GOES weather satellite data showed that a network of ground stations located in Hawaii and the Southwest continental US can provide an average of 90% availability for the deep space optical link. JPL and AFRL are exploring the use of large telescopes in Hawaii, California, and Albuquerque to support the Mars Telesat laser communications demonstration. Designed to demonstrate multi-Mbps communications from Mars, the mission will investigate key operational strategies of future deep space optical communications network.

  15. VizieR Online Data Catalog: WINGS: Deep optical phot. of 77 nearby clusters (Varela+, 2009)

    NASA Astrophysics Data System (ADS)

    Varela, J.; D'Onofrio, M.; Marmo, C.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, J. W.; Dressler, A.; Kjaergaard, P.; Moles, M.; Pignatelli, E.; Poggianti, M. B.; Valentinuzzi, T.

    2009-05-01

    This is the second paper of a series devoted to the WIde Field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long term project which is gathering wide-field, multi-band imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04200deg). The main goal of this project is to establish a local reference for evolutionary studies of galaxies and galaxy clusters. This paper presents the optical (B,V) photometric catalogs of the WINGS sample and describes the procedures followed to construct them. We have paid special care to correctly treat the large extended galaxies (which includes the brightest cluster galaxies) and the reduction of the influence of the bright halos of very bright stars. We have constructed photometric catalogs based on wide-field images in B and V bands using SExtractor. Photometry has been performed on images in which large galaxies and halos of bright stars were removed after modeling them with elliptical isophotes. We publish deep optical photometric catalogs (90% complete at V21.7, which translates to ~ MV* + 6 at mean redshift), giving positions, geometrical parameters, and several total and aperture magnitudes for all the objects detected. For each field we have produced three catalogs containing galaxies, stars and objects of "unknown" classification (~16%). From simulations we found that the uncertainty of our photometry is quite dependent of the light profile of the objects with stars having the most robust photometry and de Vaucouleurs profiles showing higher uncertainties and also an additional bias of ~-0.2m. The star/galaxy classification of the bright objects (V<20) was checked visually making negligible the fraction of misclassified objects. For fainter objects, we found that simulations do not provide reliable estimates of the possible misclassification and therefore we have compared our data with that from deep counts of galaxies and star counts from models of our Galaxy. Both sets turned

  16. The VVDS-VLA deep field. IV. Radio-optical properties

    NASA Astrophysics Data System (ADS)

    Bardelli, S.; Zucca, E.; Bolzonella, M.; Ciliegi, P.; Gregorini, L.; Zamorani, G.; Bondi, M.; Zanichelli, A.; Tresse, L.; Vergani, D.; Gavignaud, I.; Bongiorno, A.; Bottini, D.; Garilli, B.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Scaramella, R.; Scodeggio, M.; Vettolani, G.; Adami, C.; Arnouts, S.; Cappi, A.; Charlot, S.; Contini, T.; Foucaud, S.; Franzetti, P.; Guzzo, L.; Ilbert, O.; Iovino, A.; Lamareille, F.; McCracken, H. J.; Marano, B.; Marinoni, C.; Mazure, A.; Meneux, B.; Merighi, R.; Paltani, S.; Pellò, R.; Pollo, A.; Pozzetti, L.; Radovich, M.; Abbas, U.; Brinchmann, J.; Cucciati, O.; de La Torre, S.; de Ravel, L.; Memeo, P.; Perez-Montero, E.; Mellier, Y.; Merluzzi, P.; Temporin, S.; de Ruiter, H. R.; Parma, P.

    2009-02-01

    Aims: The availability of wide angle and deep surveys, both in the optical and the radio band, allows us to explore the evolution of radio sources with optical counterparts up to redshift z˜ 1.1 in an unbiased way using large numbers of radio sources and well defined control samples of radio-quiet objects. Methods: We use the 1.4 GHz VIMOS-VLA Deep Survey, the optical VIMOS-VLT Deep Survey and the CFHT Legacy Survey to compare the properties of radio-loud galaxies with respect to the whole population of optical galaxies. The availability of multiband photometry and high quality photometric redshifts allows us to derive rest-frame colors and radio luminosity functions to a limit of a B rest-frame magnitude of M_B=-20. We derive spectrophotometric types, following the classification of Zucca et al. (2006, A&A, 455, 879), in order to have a priori knowledge of the optical evolution of different galaxy classes. Results: Galaxy properties and luminosity functions are estimated up to z˜ 1 for radio-loud and radio-quiet early and late type galaxies. Radio-loud late type galaxies show significantly redder colors than radio-quiet objects of the same class and this is related to the presence of more dust in stronger star forming galaxies. We estimate the optical luminosity functions, stellar masses and star formation rate distributions for radio sources and compare them with those derived for a well defined control sample, finding that the probability of a galaxy to be a radio emitter significantly increases at high values of these parameters. Radio-loud early type galaxies exhibit luminosity evolution in their bivariate radio-optical luminosity function, due to evolution in the radio-optical ratio. The lack of evolution of the mass function of radio-loud early type galaxies means that no new AGN are formed at redshift z<1. In contrast, radio-loud late type objects exhibit a strong evolution, both in luminosity and density, of the radio luminosity function for z>0.7. This

  17. Optical photometry of GM Cep: evidence for UXor type of variability

    NASA Astrophysics Data System (ADS)

    Semkov, E. H.; Peneva, S. P.

    2012-03-01

    Results from optical photometric observations of the pre-main sequence star GM Cep are reported in the paper. The star is located in the field of the young open cluster Trumpler 37—a region of active star formation. GM Cep shows a large amplitude rapid variability interpreted as a possible outburst from EXor type in previous studies. Our data from BVRI CCD photometric observations of the star are collected from June 2008 to February 2011 in Rozhen observatory (Bulgaria) and Skinakas observatory (Crete, Greece). A sequence of sixteen comparison stars in the field of GM Cep was calibrated in the BVRI bands. Our photometric data for a 2.5 years period show a high amplitude variations (Δ V ˜2. m3) and two deep minimums in brightness are observed. The analysis of collected multicolor photometric data shows the typical of UX Ori variables a color reversal during the minimums in brightness. On the other hand, high amplitude rapid variations in brightness typical for the Classical T Tauri stars also present on the light curve of GM Cep. Comparing our results with results published in the literature, we conclude that changes in brightness are caused by superposition of both: (1) magnetically channeled accretion from the circumstellar disk, and (2) occultation from circumstellar clouds of dust or from features of a circumstellar disk.

  18. Sub-microradian pointing for deep space optical telecommunications network

    NASA Technical Reports Server (NTRS)

    Ortiz, G.; Lee, S.; Alexander, J.

    2001-01-01

    This presentation will cover innovative hardware, algorithms, architectures, techniques and recent laboratory results that are applicable to all deep space optical communication links, such as the Mars Telecommunication Network to future interstellar missions.

  19. Second Workshop on Improvements to Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William J. (Editor)

    1988-01-01

    The papers in these proceedings show that a major effort is under way to improve all aspects of photometry. Astronomical multichannel photometry, photodiodes, analog-to-digital converters, data reduction techniques, interference filters and optical fibers are discussed.

  20. Standard Galactic Field RR Lyrae. I. Optical to Mid-infrared Phased Photometry

    NASA Astrophysics Data System (ADS)

    Monson, Andrew J.; Beaton, Rachael L.; Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Rich, Jeffrey A.; Seibert, Mark; Kollmeier, Juna A.; Clementini, Gisella

    2017-03-01

    We present a multi-wavelength compilation of new and previously published photometry for 55 Galactic field RR Lyrae variables. Individual studies, spanning a time baseline of up to 30 years, are self-consistently phased to produce light curves in 10 photometric bands covering the wavelength range from 0.4 to 4.5 microns. Data smoothing via the GLOESS technique is described and applied to generate high-fidelity light curves, from which mean magnitudes, amplitudes, rise times, and times of minimum and maximum light are derived. 60,000 observations were acquired using the new robotic Three-hundred MilliMeter Telescope (TMMT), which was first deployed at the Carnegie Observatories in Pasadena, CA, and is now permanently installed and operating at Las Campanas Observatory in Chile. We provide a full description of the TMMT hardware, software, and data reduction pipeline. Archival photometry contributed approximately 31,000 observations. Photometric data are given in the standard Johnson UBV, Kron–Cousins {R}C{I}C, 2MASS JHK, and Spitzer [3.6] and [4.5] bandpasses.

  1. Statistics of intensity in adaptive-optics images and their usefulness for detection and photometry of exoplanets.

    PubMed

    Gladysz, Szymon; Yaitskova, Natalia; Christou, Julian C

    2010-11-01

    This paper is an introduction to the problem of modeling the probability density function of adaptive-optics speckle. We show that with the modified Rician distribution one cannot describe the statistics of light on axis. A dual solution is proposed: the modified Rician distribution for off-axis speckle and gamma-based distribution for the core of the point spread function. From these two distributions we derive optimal statistical discriminators between real sources and quasi-static speckles. In the second part of the paper the morphological difference between the two probability density functions is used to constrain a one-dimensional, "blind," iterative deconvolution at the position of an exoplanet. Separation of the probability density functions of signal and speckle yields accurate differential photometry in our simulations of the SPHERE planet finder instrument.

  2. A note on deep space optical communication link parameters

    NASA Technical Reports Server (NTRS)

    Dolinar, S. J.; Yuen, J. H.

    1982-01-01

    Topical communication in the context of a deep space communication link. Communication link analysis at the optical frequencies differs significantly from that at microwave frequencies such as the traditional S and X-bands used in deep space applications, due to the different technology of transmitter, antenna, modulators, and receivers. In addition, the important role of quantum noise in limiting system performance is quite different than that of thermal noise. The optical link design is put in a design control table format similar to a microwave telecom link design. Key considerations unique to the optical link are discussed.

  3. The calibration of read-out-streak photometry in the XMM-Newton Optical Monitor and the construction of a bright-source catalogue

    NASA Astrophysics Data System (ADS)

    Page, M. J.; Chan, N.; Breeveld, A. A.; Talavera, A.; Yershov, V.; Kennedy, T.; Kuin, N. P. M.; Hancock, B.; Smith, P. J.; Carter, M.

    2017-04-01

    The dynamic range of the XMM-Newton Optical Monitor (XMM-OM) is limited at the bright end by coincidence loss, the superposition of multiple photons in the individual frames recorded from its micro-channel-plate (MCP) intensified charge-coupled device (CCD) detector. One way to overcome this limitation is to use photons that arrive during the frame transfer of the CCD, forming vertical read-out streaks for bright sources. We calibrate these read-out streaks for photometry of bright sources observed with XMM-OM. The bright-source limit for read-out-streak photometry is set by the recharge time of the MCPs. For XMM-OM, we find that the MCP recharge time is 5.5 × 10-4 s. We determine that the effective bright limits for read-out-streak photometry with XMM-OM are approximately 1.5 mag brighter than the bright-source limits for normal aperture photometry in full-frame images. This translates into bright-source limits in Vega magnitudes of UVW2=7.1, UVM2=8.0, UVW1=9.4, U=10.5, B=11.5, V=10.2, and White=12.5 for data taken early in the mission. The limits brighten by up to 0.2 mag, depending on filter, over the course of the mission as the detector ages. The method is demonstrated by deriving UVW1 photometry for the symbiotic nova RR Telescopii, and the new photometry is used to constrain the e-folding time of its decaying ultraviolet (UV) emission. Using the read-out-streak method, we obtain photometry for 50 per cent of the missing UV source measurements in version 2.1 of the XMM-Newton Serendipitous UV Source Survey catalogue.

  4. Retrieval of optical depth and particle size distribution of tropospheric and stratospheric aerosols by means of sun photometry

    SciTech Connect

    Schmid, B.; Maetzler, C.; Kaempfer, N.; Heimo, A.

    1997-01-01

    Aerosol optical depth measurements by means of ground-based Sun photometry were made in Bern, Switzerland during two and a half years primarily to provide quantitative corrections for atmospheric effects in remotely sensed data in the visible and near-infrared spectral region. An investigation of the spatial variability of tropospheric aerosol was accomplished in the summer of 1994 in the Swiss Central Plain, a region often covered by a thick aerosol layer. Intercomparisons are made with two Sun photometers operated by the Swiss Meteorological Institute in Payerne and Davos. By means of an inversion technique, columnar particle size distributions were derived from the aerosol optical depth spectra. Effective radius, columnar surface area, and columnar mass were computed from the inversion results. Most of the spectra measured in Bern exhibit an Angstroem-law dependence. Consequently, the inverted size distributions are very close to power-law distributions. Data collected during a four month calibration campaign in fall 1993 at a high-mountain station in the Swiss Alps allowed the authors to study optical properties of stratospheric aerosol. The extinction spectra measured have shown to be still strongly influenced by remaining aerosol of the June 1991 volcanic eruptions of Mount Pinatubo. Inverted particle size distributions can be characterized by a broad monodisperse peak with a mode radius around 0.25 {micro}m. Both aerosol optical depths and effective radii had not yet returned to pre-eruption values. Comparison of retrieved aerosol optical depth, columnar surface area and mass, with the values derived from lidar observations performed in Garmisch-Partenkirchen, Southern-Germany, yielded good agreement.

  5. Astronomical photometry

    NASA Astrophysics Data System (ADS)

    Henden, Arne A.; Kaitchuck, Ronald H.

    A handbook of astronomical photometry is presented in a format amenable to both professional and amateur use. The fundamental equipment, procedures, theory, and applications of photometry are described. Photometric systems such as the UBV, M-K, and Stromgren classification methods are explained, together with statistical treatments of photometric data. Data reduction techniques and applications in air-mass calculations, the determination of first-order extinction, and for computing zero-point values are defined. Baseline standards such as solar, universal,and sidereal time, and dating methods are provided. Instructions for constructing photometer heads are given, and the operational principles and techniques for using pulse-counting and dc electronics are explored. Finally, observational techniques and applications of photoelectric photometry are suggested and targets are indicated. A review is also offered of the theoretical basis and computational tools involved in the science of astronomical photometry.

  6. Research and development optical deep space antenna sizing study

    NASA Technical Reports Server (NTRS)

    Wonica, D.

    1994-01-01

    Results from this study provide a basis for the selection of an aperture size appropriate for a research and development ground-based receiver for deep space optical communications. Currently achievable or near-term realizable hardware performance capabilities for both a spacecraft optical terminal and a ground terminal were used as input parameters to the analysis. Links were analyzed using OPTI, our optical link analysis program. Near-term planned and current missions were surveyed and categorized by data rate and telecommunications-subsystems prime power consumption. The spacecraft optical-terminal transmitter power was selected by matching these (RF) data rates and prime power requirements and by applying power efficiencies suitable to an optical communications subsystem. The study was baselined on a Mars mission. Results are displayed as required ground aperture size for given spacecraft transmitter aperture size, parametrized by data rate, transmit optical power, and wavelength.

  7. EDGES: Deep Multi-Wavelength Photometry and Radial SED Analysis for NGC4485, NGC4490 and NGC5273

    NASA Astrophysics Data System (ADS)

    Gillian, Beltz-Mohrmann; Dale, Daniel A.; Barnes, Kate L.; Egan, Arika; Hatlestad, Alan; Herzog, Laura; Kobulnicky, Henry A.; Leung, Andrew S.; McLane, Jacob; Phenicie, Christopher; Roberts, Jareth; Staudaher, Shawn; van Zee, Liese

    2015-01-01

    New deep ugr imaging was obtained on the Wyoming Infrared Observatory 2.3 meter telescope for NGC4485, NGC4490 and NGC5273, three galaxies in the Extended Disk Galaxy Exploration Science survey. These data are coupled with deep GALEX ultraviolet and Spitzer/Herschel infrared imaging to study the radial variations in the spectral energy distributions. Results from the CIGALE SED modeling software will be presented, including trends in the galaxy star formation histories. This work is supported by the National Science Foundation under REU grant AST 1063146.

  8. Deep space uplink receiver prototype for optical communications

    NASA Astrophysics Data System (ADS)

    Sburlan, S. E.; Birnbaum, K. M.; Farr, W. H.

    2011-03-01

    A hardware prototype of a flight receiver for deep space optical communications has been developed where a single detector array is used for acquisition, tracking, and high-speed data recovery. A counting algorithm accumulates pulses on every pixel in a photon-counting array and extracts signal information encoded with a nested modulation scheme.

  9. Low-energy K- optical potentials: deep or shallow?

    NASA Astrophysics Data System (ADS)

    Cieplý, A.; Friedman, E.; Gal, A.; Mareš, J.

    2001-12-01

    The K- optical potential in the nuclear medium is evaluated self consistently from a free-space K-Nt matrix constructed within a coupled-channel chiral approach. The fit of model parameters gives a good description of the low-energy data plus the available K- atomic data. The resulting optical potential is relatively `shallow' in contradiction to the potentials obtained from phenomenological analysis. The calculated (Kstop-,π) hypernuclear production rates are very sensitive to the details of kaonic bound state wave function. The (Kstop-,π) reaction could thus serve as a suitable tool to distinguish between shallow and deep K- optical potentials.

  10. Probing Accretion in Magnetic Cataclysmic Variables from High Time Resolution Optical Photometry and X-ray Observations from ASTROSAT

    NASA Astrophysics Data System (ADS)

    Buckley, David; Marsh, Tom; Revnivtsev, Mikhail; Bonnet-Bidaud, Jean-Marc; Mouchet, Martine; Pal Singh, Kulinder; Semena, Andrey; Dhillon, Vik; Breytenbach, Hannes; Irawati, Puji; Potter, Stephen

    2016-07-01

    We present results from an on-going program of high speed CCD photometry of magnetic cataclysmic variables (mCVs) aimed at characterizing their high frequency (˜0.1-10 Hz) optical variability. In particular, we have been actively attempting to detect Quasi-Periodic Oscillations in many Polars, indicative of shock instabilities in their accretion columns. We have used a variety of instruments for this purpose, including the EM-CCD based SHOC camera on the SAAO 1.9-m telescope, SALTICAM and BVIT on SALT and Ultraspec on the TNO 2.5-m telescope. While we have detected QPOs seen before in the systems V834 Cen and VV Pup, we have only found evidence for one new detection, namely for 2MASS J19283247-5001344, an eclipsing polar. This may indicate that QPOs are somewhat of a rarity in Polars. We have also seen evidence for lower frequency QPOs, with characteristic timescales of 10s of seconds to several minutes. In addition, we have been investigating the nature of the breaks in the Power Density Spectra (νF_ν) power law for Intermediate Polars (e.g. EX Hya). This may give clues to the size of the inner radius of the accretion disc, where the magnetosphere begins to dominate the accretion flow. Finally, results of our recent ASTROSAT program on mCVs will be discussed.

  11. OPTICAL AND INFRARED PHOTOMETRY OF GLOBULAR CLUSTERS IN NGC 1399: EVIDENCE FOR COLOR-METALLICITY NONLINEARITY

    SciTech Connect

    Blakeslee, John P.; Ferrarese, Laura; Martel, Andre R.; Cho, Hyejeon; Peng, Eric W.; Jordan, Andres

    2012-02-10

    We combine new Wide Field Camera 3 IR Channel (WFC3/IR) F160W (H{sub 160}) imaging data for NGC 1399, the central galaxy in the Fornax cluster, with archival F475W (g{sub 475}), F606W (V{sub 606}), F814W (I{sub 814}), and F850LP (z{sub 850}) optical data from the Advanced Camera for Surveys (ACS). The purely optical g{sub 475} - I{sub 814}, V{sub 606} - I{sub 814}, and g{sub 475} - z{sub 850} colors of NGC 1399's rich globular cluster (GC) system exhibit clear bimodality, at least for magnitudes I{sub 814} > 21.5. The optical-IR I{sub 814} - H{sub 160} color distribution appears unimodal, and this impression is confirmed by mixture modeling analysis. The V{sub 606} - H{sub 160} colors show marginal evidence for bimodality, consistent with bimodality in V{sub 606} - I{sub 814} and unimodality in I{sub 814} - H{sub 160}. If bimodality is imposed for I{sub 814} - H{sub 160} with a double Gaussian model, the preferred blue/red split differs from that for optical colors; these 'differing bimodalities' mean that the optical and optical-IR colors cannot both be linearly proportional to metallicity. Consistent with the differing color distributions, the dependence of I{sub 814} - H{sub 160} on g{sub 475} - I{sub 814} for the matched GC sample is significantly nonlinear, with an inflection point near the trough in the g{sub 475} - I{sub 814} color distribution; the result is similar for the I{sub 814} - H{sub 160} dependence on g{sub 475} - z{sub 850} colors taken from the ACS Fornax Cluster Survey. These g{sub 475} - z{sub 850} colors have been calibrated empirically against metallicity; applying this calibration yields a continuous, skewed, but single-peaked metallicity distribution. Taken together, these results indicate that nonlinear color-metallicity relations play an important role in shaping the observed bimodal distributions of optical colors in extragalactic GC systems.

  12. Photon counting detector array algorithms for deep space optical communications

    NASA Astrophysics Data System (ADS)

    Srinivasan, Meera; Andrews, Kenneth S.; Farr, William H.; Wong, Andre

    2016-03-01

    For deep-space optical communications systems utilizing an uplink optical beacon, a single-photon-counting detector array on the flight terminal can be used to simultaneously perform uplink tracking and communications as well as accurate downlink pointing at photon-starved (pW=m2) power levels. In this paper, we discuss concepts and algorithms for uplink signal acquisition, tracking, and parameter estimation using a photon-counting camera. Statistical models of detector output data and signal processing algorithms are presented, incorporating realistic effects such as Earth background and detector/readout blocking. Analysis and simulation results are validated against measured laboratory data using state-of-the-art commercial photon-counting detector arrays, demonstrating sub-microradian tracking errors under channel conditions representative of deep space optical links.

  13. Photographic photometry of compact extragalactic objects Optical variability of the quasar 3C 345

    NASA Astrophysics Data System (ADS)

    Babadzhanyants, M. K.; Belokon, E. T.; Denisenko, N. S.; Semenova, E. V.

    1985-08-01

    The results of 11-years photographic observations of optical variability of the quasar 3C 345 are presented. A flare with a timescale of the order of one year, similar to those of 1967 and 1971, was observed in 1982. From a comparison of the obtained series of observations with those of the Rosemary Hill Observatory, a conclusion is drawn on the absence of systematic variability at a timescale of 5 - 20 hours exceeding 0m.2 in magnitude.

  14. Photographic photometry of compact extragalactic objects Optical variability of the quasar 3C 345

    SciTech Connect

    Babadzhaniants, M.K.; Belokon, E.T.; Denisenko, N.S.; Semenova, E.V.

    1985-08-01

    An 11-yr (1973-1983) program of photographic observations at the Leningrad Byurakan station is reported, tracing the optical variability of the quasar 3C 345. A roughly 1-yr flare resembling those of 1967 and 1971 occurred in 1982. Comparison with the concurrent observations at Rosemary Hill, Florida, shows no appreciable systematic B-band fluctuations on time scales of 5-20 h. 10 references.

  15. Ultraviolet spectrophotometry and optical and infrared photometry of the old nova GK Persei

    NASA Technical Reports Server (NTRS)

    Wu, Chi-Chao; Holm, Albert V.; Panek, Robert J.; Raymond, John C.; Hartmann, Lee W.; Swank, Jean H.

    1989-01-01

    IUE observations in the 1150-3250-A region were obtained of GK Per during the rise, at the maximum, and during the decline of the 2.5-mag optical outburst in 1981. The results support previous predictions for the interaction of an accretion disk with the magnetic field of an accretion star. The luminosity at minimum is found to be 2.3 solar luminosities, with 1/3 of this being attributed to the cool secondary star.

  16. S-CANDELS: The Spitzer-Cosmic Assembly Near-Infrared Deep Extragalactic Survey. Survey Design, Photometry, and Deep IRAC Source Counts

    NASA Astrophysics Data System (ADS)

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Dunlop, J. S.; Egami, E.; Faber, S. M.; Ferguson, H. C.; Grogin, N. A.; Hora, J. L.; Huang, J.-S.; Koekemoer, A. M.; Labbé, I.; Wang, Z.

    2015-06-01

    The Spitzer-Cosmic Assembly Deep Near-infrared Extragalactic Legacy Survey (S-CANDELS; PI G.Fazio) is a Cycle 8 Exploration Program designed to detect galaxies at very high redshifts (z\\gt 5). To mitigate the effects of cosmic variance and also to take advantage of deep coextensive coverage in multiple bands by the Hubble Space Telescope (HST) Multi-cycle Treasury Program CANDELS, S-CANDELS was carried out within five widely separated extragalactic fields: the UKIDSS Ultra-deep Survey, the Extended Chandra Deep Field South, COSMOS, the HST Deep Field North, and the Extended Groth Strip. S-CANDELS builds upon the existing coverage of these fields from the Spitzer Extended Deep Survey (SEDS), a Cycle 6 Exploration Program, by increasing the integration time from SEDS’ 12 hr to a total of 50 hr but within a smaller area, 0.16 deg2. The additional depth significantly increases the survey completeness at faint magnitudes. This paper describes the S-CANDELS survey design, processing, and publicly available data products. We present Infrared Array Camera (IRAC) dual-band 3.6+4.5 μ {{m}} catalogs reaching to a depth of 26.5 AB mag. Deep IRAC counts for the roughly 135,000 galaxies detected by S-CANDELS are consistent with models based on known galaxy populations. The increase in depth beyond earlier Spitzer/IRAC surveys does not reveal a significant additional contribution from discrete sources to the diffuse Cosmic Infrared Background (CIB). Thus it remains true that only roughly half of the estimated CIB flux from COBE/DIRBE is resolved.

  17. Optical Photometry and X-Ray Monitoring of the ``Cool Algol'' BD +05°706: Determination of the Physical Properties

    NASA Astrophysics Data System (ADS)

    Torres, Guillermo; Mader, Jeff A.; Marschall, Laurence A.; Neuhäuser, Ralph; Duffy, Alaine S.

    2003-06-01

    We present new photometric observations in the BVRI bands of the double-lined eclipsing binary BD +05°706 conducted over three observing seasons, as well as new X-ray observations obtained with ROSAT covering a full orbital cycle (P=18.9 days). A detailed light-curve analysis of the optical data shows the system to be semidetached, confirming indications from an earlier analysis by Torres et al. (published in 1998), with the less massive and cooler star filling its Roche lobe. The system is a member of the rare class of cool Algol systems, which are different from the ``classical'' Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the new photometry with a reanalysis of the spectroscopic observations reported by Torres et al., we derive accurate absolute masses for the components of M1=2.633+/-0.028 Msolar and M2=0.5412+/-0.0093 Msolar, radii of R1=7.55+/-0.20 Rsolar and R2=11.02+/-0.21 Rsolar, as well as effective temperatures of 5000+/-100 and 4640+/-150 K, for the primary and secondary, respectively. There are obvious signs of activity (spottedness) in the optical light curve of the binary. Our X-ray light curve clearly shows the primary eclipse but not the secondary eclipse, suggesting that the primary star is the dominant source of the activity in the system. The depth and duration of the eclipse allow us to infer some of the properties of the X-ray-emitting region around that star.

  18. Optical dual-band photometry and spectroscopy of the WZ Sge-type dwarf nova EZ Lyn during the 2010 superoutburst

    NASA Astrophysics Data System (ADS)

    Isogai, Mizuki; Arai, Akira; Yonehara, Atsunori; Kawakita, Hideyo; Uemura, Makoto; Nogami, Daisaku

    2015-02-01

    We performed optical simultaneous dual-band (SDSS g'- and i'-bands) photometry and low-resolution spectroscopy for the WZ Sge-type dwarf nova EZ Lyn during its 2010 superoutburst. Dual-band photometry revealed that the g'- i' color reddened with a decrease in brightness during the main superoutburst and the following rebrightening phase, whereas the color became bluer with a further decrease in brightness during the slow, final decline phase. With a fit to our photometric results by a blackbody function, we estimated the disk radius ratio (ratio of the disk radius to the binary separation) and compared this with that of V455 And, a WZ Sge-type object that did not show any rebrightening in the 2007 superoutburst. The comparison revealed: (1) the disk radius ratio of EZ Lyn decreased more slowly than that of V455 And, and (2) the radius ratio of EZ Lyn at the end of the main superoutburst was larger than that of V455 And. These results favor the mass reservoir model for the mechanism of rebrightening. During both the superoutburst plateau and subsequent rebrightening phase, Hα and Hβ lines were detected. The Hα line showed a double-peak profile from which we estimated the disk radius ratio. The comparison of this ratio with that derived by photometry indicates that the Hα disk was larger than the photometric one, which suggests that the optically thin gas was extended to the outer region more than the optically thick gas disk and was possibly responsible for the rebrightening phenomenon. Time-series dual-band photometry during the main superoutburst revealed that color variations during the early superhump show roughly the same behavior as that of V455 And, whereas color variations during the ordinary superhump display clear anticorrelation with brightness, in contrast to that seen in V455 And. Here, we discuss different color behaviors.

  19. Architectural Options for a Future Deep Space Optical Communications Network

    NASA Technical Reports Server (NTRS)

    Edwards, B. L.; Benjamin, T.; Scozzafava, J.; Khatri, F.; Sharma, J.; Parvin, B.; Liebrecht, P. E.; Fitzgerald, R. J.

    2004-01-01

    This paper provides an overview of different options at Earth to provide Deep Space optical communication services. It is based mainly on work done for the Mars Laser Communications Demonstration (MLCD) Project, a joint project between NASA's Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory, California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL). It also reports preliminary conclusions from the Tracking and Data Relay Satellite System Continuation Study at GSFC. A lasercom flight terminal will be flown on the Mars Telecommunications Orbiter (MTO) to be launched by NASA in 2009, and will be the first high rate deep space demonstration of this revolutionary technology.

  20. Optical Photometry of the Black Hole Candidate SWIFT J1753.4-0126

    NASA Astrophysics Data System (ADS)

    Paez, Aurelio; Mason, P. A.; Robinson, E. L.; Bayless, A. J.

    2012-01-01

    We present optical observations of the black hole candidate LMXB SWIFT J1753.4-0126 with the 2.1m Otto Struve Telescope of McDonald Observatory. The Argos CCD photometer was used and 10s integrations were obtained on 19 nights in 2010 and 2011. We performed a period search using a Phase Dispersion Minimization (PDM) code and we obtain a period of 3.2448 +/- 0.0002hr. This new period is fully consistent with, and a factor of 5 improvement over, the PDM period of (Zurita et al. 2008). The individual light curves are complex and variable. This work is part of the NSF/PAARE program for Education and Research.

  1. High Speed Optical Photometry of V1055 Orionis (=4U 0614+091)

    NASA Astrophysics Data System (ADS)

    Lopez, Isaac; Mason, P. A.; Robinson, E. L.

    2013-01-01

    V1055 Orionis (=4U 0614+091) is thought to be an ultra-compact binary containing a neutron star primary with a white dwarf companion. High-speed (10s) broad-band optical observations using the McDonald Observatory, 2.1m, Otto Struve Telescope were obtained on 13 nights in 2010, 2011, and 2012. The nightly mean brightness remained quite stable over the dataset. The light curve is dominated by complex oscillatory behavior reminiscent of the beating of hidden frequencies. A variety of photometric periods have been previously reported and none are found to be coherent periods in our dataset. Rather, a given night exhibits short lived quasi-periodic variations covering a variety of timescales, especially 10-40 min and even as long as two hours. This short period variability combined with recent spectroscopic abundance studies suggests that the likely donor in this binary is a white dwarf.

  2. Optical spectroscopy and photometry of main-belt asteroids with a high orbital inclination

    NASA Astrophysics Data System (ADS)

    Iwai, Aya; Itoh, Yoichi; Terai, Tsuyoshi; Gupta, Ranjan; Sen, Asoke; Takahashi, Jun

    2017-02-01

    We carried out low-resolution optical spectroscopy of 51 main-belt asteroids, most of which have highly-inclined orbits. They are selected from D-type candidates in the SDSS-MOC 4 catalog. Using the University of Hawaii 2.2 m telescope and the Inter-University Centre for Astronomy and Astrophysics 2 m telescope in India, we determined the spectral types of 38 asteroids. Among them, eight asteroids were classified as D-type asteroids. Fractions of D-type asteroids are 3.0+/-1.1 for low orbital inclination main-belt asteroids and 7.3+/-2.0 for high orbital inclination main-belt asteroids. The results of our study indicate that some D-type asteroids were formed within the ecliptic region between the main belt and Jupiter, and were then perturbed by Jupiter.

  3. Beaconless Pointing for Deep-Space Optical Communication

    NASA Technical Reports Server (NTRS)

    Swank, Aaron J.; Aretskin-Hariton, Eliot; Le, Dzu K.; Sands, Obed S.; Wroblewski, Adam

    2016-01-01

    Free space optical communication is of interest to NASA as a complement to existing radio frequency communication methods. The potential for an increase in science data return capability over current radio-frequency communications is the primary objective. Deep space optical communication requires laser beam pointing accuracy on the order of a few microradians. The laser beam pointing approach discussed here operates without the aid of a terrestrial uplink beacon. Precision pointing is obtained from an on-board star tracker in combination with inertial rate sensors and an outgoing beam reference vector. The beaconless optical pointing system presented in this work is the current approach for the Integrated Radio and Optical Communication (iROC) project.

  4. Deep-space Optical Terminals (DOT) Systems Engineering

    NASA Astrophysics Data System (ADS)

    Biswas, A.; Hemmati, H.; Piazzolla, S.; Moision, B.; Birnbaum, K.; Quirk, K.

    2010-11-01

    Recently a conceptual design study titled Deep-space Optical Terminals (DOT) was completed for a deep-space optical communication technology demonstration in the 2018 timeframe. This article provides an overview of the system engineering portion of the study. The Level 1 requirements received from the NASA Space Communications and Navigation Program Manager emphasized an order of magnitude higher data rate from Mars closest range relative to the Ka-band telecommunication system flown on the Mars Reconnaissance Orbiter (MRO) mission but utilizing comparable mass and power. The system-level concept design motivated by this driving requirement and reported here describes link performance of 267 Mb/s from 0.42 AU within an allocated mass and power of 38 kg and 110 W. Furthermore, the concept design addresses link closure at the farthest Mars range of 2.7 AU. Maximum uplink data rates of 292 kb/s and ranging with 30-cm precision are also addressed.

  5. Deep ultraviolet laser micromachining of novel fibre optic devices

    NASA Astrophysics Data System (ADS)

    Li, J.; Dou, J.; Herman, P. R.; Fricke-Begemann, T.; Ihlemann, J.; Marowsky, G.

    2007-04-01

    A deep ultraviolet F2 laser, with output at 157-nm wavelength, has been adopted for micro-shaping the end facets of single and multi-mode silica optical fibres. The high energy 7.9-eV photons drive strong interactions in the wide-bandgap silica fibres to enable the fabrication of surface-relief microstructures with high spatial resolution and smooth surface morphology. Diffraction gratings, focusing lenses, and Mach-Zehnder interferometric structures have been micromachined onto the cleaved-fibre facets and optically characterized. F2-laser micromachining is shown to be a rapid and facile means for direct-writing of novel infibre photonic components.

  6. Microsecond Time Resolution Optical Photometry using a H.E.S.S. Cherenkov Telescope

    SciTech Connect

    Deil, Christoph; Domainko, Wilfried; Hermann, German

    2008-02-22

    We have constructed an optical photometer with microsecond time resolution, which is currently being operated on one of the H.E.S.S. telescopes. H.E.S.S. is an array of four Cherenkov telescopes, each with a 107 m{sup 2} mirror, located in the Khomas highland in Namibia. In its normal mode of operation H.E.S.S. observes Cherenkov light from air showers generated by very high energy gamma-rays in the upper atmosphere. Our detector consists of seven photomultipliers, one in the center to record the lightcurve from the target and six concentric photomultipliers as a veto system to reject disturbing signals e.g. from meteorites or lightning at the horizon. The data acquisition system has been designed to continuously record the signals with zero deadtime. The Crab pulsar has been observed to verify the performance of the instrument and the GPS timing system. Compact galactic targets were observed to search for flares on timescales of a few microseconds to {approx}100 ms. The design and sensitivity of the instrument as well as the data analysis method are presented.

  7. Optical subnet concepts for the deep space network

    NASA Technical Reports Server (NTRS)

    Shaik, K.; Wonica, D.; Wilhelm, M.

    1993-01-01

    This article describes potential enhancements to the Deep Space Network, based on a subnet of receiving stations that will utilize optical communications technology in the post-2010 era. Two optical subnet concepts are presented that provide full line-of-sight coverage of the ecliptic, 24 hours a day, with high weather availability. The technical characteristics of the optical station and the user terminal are presented, as well as the effects of cloud cover, transmittance through the atmosphere, and background noise during daytime or nighttime operation on the communications link. In addition, this article identifies candidate geographic sites for the two network concepts and includes a link design for a hypothetical Pluto mission in 2015.

  8. Deep-Space Optical Communications: Visions, Trends, and Prospects

    NASA Technical Reports Server (NTRS)

    Cesarone, R. J.; Abraham, D. S.; Shambayati, S.; Rush, J.

    2011-01-01

    Current key initiatives in deep-space optical communications are treated in terms of historical context, contemporary trends, and prospects for the future. An architectural perspective focusing on high-level drivers, systems, and related operations concepts is provided. Detailed subsystem and component topics are not addressed. A brief overview of past ideas and architectural concepts sets the stage for current developments. Current requirements that might drive a transition from radio frequencies to optical communications are examined. These drivers include mission demand for data rates and/or data volumes; spectrum to accommodate such data rates; and desired power, mass, and cost benefits. As is typical, benefits come with associated challenges. For optical communications, these include atmospheric effects, link availability, pointing, and background light. The paper describes how NASA's Space Communication and Navigation Office will respond to the drivers, achieve the benefits, and mitigate the challenges, as documented in its Optical Communications Roadmap. Some nontraditional architectures and operations concepts are advanced in an effort to realize benefits and mitigate challenges as quickly as possible. Radio frequency communications is considered as both a competitor to and a partner with optical communications. The paper concludes with some suggestions for two affordable first steps that can yet evolve into capable architectures that will fulfill the vision inherent in optical communications.

  9. WINGS: a WIde-field nearby Galaxy-cluster survey. III. Deep near-infrared photometry of 28 nearby clusters

    NASA Astrophysics Data System (ADS)

    Valentinuzzi, T.; Woods, D.; Fasano, G.; Riello, M.; D'Onofrio, M.; Varela, J.; Bettoni, D.; Cava, A.; Couch, W. J.; Dressler, A.; Fritz, J.; Moles, M.; Omizzolo, A.; Poggianti, B. M.; Kjærgaard, P.

    2009-07-01

    Context: This is the third paper in a series devoted to the WIde-field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long-term project aimed at gathering wide-field, multiband imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04deep near-infrared photometric catalogs (90% complete in detection rate at total magnitudes J≈ 20.5, K≈ 19.4, and in classification rate at J≈19.5 and K≈ 18.5), giving positions, geometrical parameters, total and aperture magnitudes for all detected sources. For each field we classify the detected sources as stars, galaxies, and objects of “unknown” nature. Based on observations taken at the United Kingdom Infra-Red Telescope, operated by the Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the UK. J and K photometric catalogs are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/851

  10. EUVE photometry of SS Cygni: Dwarf nova outbursts and oscillations

    SciTech Connect

    Mauche, C.W.

    1995-05-15

    The authors present EUVE Deep Survey photometry and AAVSO optical measurements of the 1993 August and 1994 June/July outbursts of the dwarf nova SS Cygni. The EUV and optical light curves are used to illustrate the different response of the accretion disk to outbursts which begin at the inner edge and propagate outward, and those which begin at the outer edge and propagate inward. Furthermore, the authors describe the properties of the quasi-coherent 7--9 s sinusoidal oscillations in the EUV flux detected during the rise and plateau stages of these outbursts.

  11. An ATP System for Deep-Space Optical Communication

    NASA Technical Reports Server (NTRS)

    Lee, Shinhak; Irtuzm Gerardi; Alexander, James

    2008-01-01

    An acquisition, tracking, and pointing (ATP) system is proposed for aiming an optical-communications downlink laser beam from deep space. In providing for a direction reference, the concept exploits the mature technology of star trackers to eliminate the need for a costly and potentially hazardous laser beacon. The system would include one optical and two inertial sensors, each contributing primarily to a different portion of the frequency spectrum of the pointing signal: a star tracker (<10 Hz), a gyroscope (<50 Hz), and a precise fluid-rotor inertial angular-displacement sensor (sometimes called, simply, "angle sensor") for the frequency range >50 Hz. The outputs of these sensors would be combined in an iterative averaging process to obtain high-bandwidth, high-accuracy pointing knowledge. The accuracy of pointing knowledge obtainable by use of the system was estimated on the basis of an 8-cm-diameter telescope and known parameters of commercially available star trackers and inertial sensors: The single-axis pointing-knowledge error was found to be characterized by a standard deviation of 150 nanoradians - below the maximum value (between 200 and 300 nanoradians) likely to be tolerable in deep-space optical communications.

  12. Disk Galaxies in the Outer Local Supercluster: Optical CCD Surface Photometry and Distribution of Galaxy Disk Parameter

    NASA Technical Reports Server (NTRS)

    Lu, N. Y.

    1998-01-01

    We report new B-band CCD surface photometry on a sample of 76 disk galaxies brighter than BT = 14.5 mag in the Uppsala General Catalogue of Galaxies, which are confined within a volume located in the outer part of the Local Supercluster.

  13. Deep and Clear Optical Imaging of Thick Inhomogeneous Samples

    PubMed Central

    Andilla, Jordi; Maandhui, Amina; Frongia, Céline; Lobjois, Valérie; Ducommun, Bernard; Lorenzo, Corinne

    2012-01-01

    Inhomogeneity in thick biological specimens results in poor imaging by light microscopy, which deteriorates as the focal plane moves deeper into the specimen. Here, we have combined selective plane illumination microscopy (SPIM) with wavefront sensor adaptive optics (wao). Our waoSPIM is based on a direct wavefront measure using a Hartmann-Shack wavefront sensor and fluorescent beads as point source emitters. We demonstrate the use of this waoSPIM method to correct distortions in three-dimensional biological imaging and to improve the quality of images from deep within thick inhomogeneous samples. PMID:22558226

  14. Replication of deep micro-optical components prototyped by Deep Proton Writing

    NASA Astrophysics Data System (ADS)

    Van Erps, J.; Wissmann, M.; Guttmann, M.; Hartmann, M.; Desmet, L.; Debaes, C.; Mohr, J.; Thienpont, H.

    2008-04-01

    Using our rapid prototyping technology called Deep Proton Writing (DPW), we have in recent years made a wide range of micro-optical components with a large depth (500-μm) for a variety of applications. One of these components is a pluggable out-of-plane coupler for printed circuit board-level optical interconnections. Whereas DPW is capable of rapidly fabricating high-quality master components, the technology is not suitable for low-cost mass fabrication. Therefore, we investigate the replication of out-of-plane coupling components using hot embossing, through the fabrication of a metal mould of the DPW master by applying electroplating. We compare these hot embossed replicas with components replicated using the elastomeric mould vacuum casting technology.

  15. BV RI CCD photometry of 361,281 objects in the field of M 31

    NASA Technical Reports Server (NTRS)

    Magnier, E. A.; Lewin, W. H. G.; Van Paradijs, J.; Hasinger, G.; Jain, A.; Pietsch, W.; Truemper, J.

    1992-01-01

    Deep BV RI CCD photometry was performed on a 1 sq deg region of M 31. A catalog of photometry and astrometry of a total of 361,281 stars is presented, with typical completion limits of BV RI = (22.3, 22.2, 22.2, 20.9). Photometric accuracy is about 2 percent at V = 19. This catalog allows detailed studies of stellar populations and reddening. The data are currently being used to assist in finding the optical counterparts of Einstein and ROSAT X-ray sources.

  16. NEW EXTINCTION AND MASS ESTIMATES FROM OPTICAL PHOTOMETRY OF THE VERY LOW MASS BROWN DWARF COMPANION CT CHAMAELEONTIS B WITH THE MAGELLAN AO SYSTEM

    SciTech Connect

    Wu, Ya-Lin; Close, Laird M.; Males, Jared R.; Morzinski, Katie M.; Follette, Katherine B.; Bailey, Vanessa; Rodigas, Timothy J.; Hinz, Philip; Barman, Travis S.; Puglisi, Alfio; Xompero, Marco; Briguglio, Runa

    2015-03-01

    We used the Magellan adaptive optics system and its VisAO CCD camera to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths. We detect it at r', i', z', and Y{sub S}. With our new photometry and T {sub eff} ∼ 2500 K derived from the shape of its K-band spectrum, we find that CT Cha B has A{sub V} = 3.4 ± 1.1 mag, and a mass of 14-24 M{sub J} according to the DUSTY evolutionary tracks and its 1-5 Myr age. The overluminosity of our r' detection indicates that the companion has significant Hα emission and a mass accretion rate ∼6 × 10{sup –10} M {sub ☉} yr{sup –1}, similar to some substellar companions. Proper motion analysis shows that another point source within 2'' of CT Cha A is not physical. This paper demonstrates how visible wavelength adaptive optics photometry (r', i', z', Y{sub S}) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions.

  17. Optical-communication systems for deep-space applications

    NASA Technical Reports Server (NTRS)

    Vilnrotter, V. A.; Gagliardi, R. M.

    1980-01-01

    The feasibility of using optical communication systems for data telemetry from deep space vehicles to Earth based receivers is evaluated. Performance analysis shows that practical, photon counting optical systems can transmit data reliably at 30 to 40 dB high rates than existing RF systems, or can be used to extend the communication range by 15 to 20 dB. The advantages of pulse-position modulation (PPM) formats are discussed, and photon counting receiver structures designed for PPM decoding are described. The effects of background interference and weather on receiver performance are evaluated. Some consideration is given to tracking and beam pointing operations, since system performance ultimately depends on the accuracy to which these operations can be carried out. An example of a tracking and pointing system utilizing an optical uplink beacon is presented, and it is shown that microradian beam pointing is within the capabilities of state-of-the-art technology. Recommendations for future theoretical studies and component development programs are presented.

  18. Deep-tissue optical imaging of decubitus ulcers

    NASA Astrophysics Data System (ADS)

    Moza, Rohin; DiMaio, J. Michael; Melendez, Jose

    2011-03-01

    Decubitus ulcers are a costly and widespread issue in healthcare today, that result from impaired blood flow in skin and underlying muscle and tissue. To address this need, a point of care multi-wavelength diagnostic imaging system has been developed to monitor hemodynamic processes via use of optical imaging of deep tissue. The resulting measurements demonstrate changes in light-tissue interaction to differentiate healthy and pathologic tissue without disturbing patients in a hospital setting. The identification of light source-detector illumination patterns uniquely map to spatial depths of tissue. The additional time dependent component, allows a novel four-dimensional analysis of tissue. The portable, noninvasive, and non-contact features provide quantitative in-situ measurements.

  19. Deep-Space Optical Transceiver Uplink Detection Analysis

    NASA Astrophysics Data System (ADS)

    Tkacenko, A.; Quirk, J. J.; Srinivasan, M.

    2013-05-01

    In this article, we develop and analyze an uplink signal detection technique for the Deep-Space Optical Transceiver (DOT). Here, the detection is carried out using a set of test statistics obtained from up-down counter (UDC) photon detection systems. Specifically, we address two sets of statistics: the count outputs from a bank of uniformly temporally spaced UDCs as well as the counts from a single UDC that cycles through multiple uniformly spaced timing phases. From these test statistics, we derive the Neyman-Pearson decision rule under certain input conditions and analyze the performance of this hypothesis test. We show the performance trade-offs associated with both sets of test statistics, which can then be used to determine which set to use as well as the number of UDCs or timing phases required for implementation.

  20. Bioabsorbable polymer optical waveguides for deep-tissue photomedicine

    PubMed Central

    Nizamoglu, Sedat; Gather, Malte C.; Humar, Matjaž; Choi, Myunghwan; Kim, Seonghoon; Kim, Ki Su; Hahn, Sei Kwang; Scarcelli, Giuliano; Randolph, Mark; Redmond, Robert W.; Yun, Seok Hyun

    2016-01-01

    Advances in photonics have stimulated significant progress in medicine, with many techniques now in routine clinical use. However, the finite depth of light penetration in tissue is a serious constraint to clinical utility. Here we show implantable light-delivery devices made of bio-derived or biocompatible, and biodegradable polymers. In contrast to conventional optical fibres, which must be removed from the body soon after use, the biodegradable and biocompatible waveguides may be used for long-term light delivery and need not be removed as they are gradually resorbed by the tissue. As proof of concept, we demonstrate this paradigm-shifting approach for photochemical tissue bonding (PTB). Using comb-shaped planar waveguides, we achieve a full thickness (>10 mm) wound closure of porcine skin, which represents ∼10-fold extension of the tissue area achieved with conventional PTB. The results point to a new direction in photomedicine for using light in deep tissues. PMID:26783091

  1. Bioabsorbable polymer optical waveguides for deep-tissue photomedicine

    NASA Astrophysics Data System (ADS)

    Nizamoglu, Sedat; Gather, Malte C.; Humar, Matjaž; Choi, Myunghwan; Kim, Seonghoon; Kim, Ki Su; Hahn, Sei Kwang; Scarcelli, Giuliano; Randolph, Mark; Redmond, Robert W.; Yun, Seok Hyun

    2016-01-01

    Advances in photonics have stimulated significant progress in medicine, with many techniques now in routine clinical use. However, the finite depth of light penetration in tissue is a serious constraint to clinical utility. Here we show implantable light-delivery devices made of bio-derived or biocompatible, and biodegradable polymers. In contrast to conventional optical fibres, which must be removed from the body soon after use, the biodegradable and biocompatible waveguides may be used for long-term light delivery and need not be removed as they are gradually resorbed by the tissue. As proof of concept, we demonstrate this paradigm-shifting approach for photochemical tissue bonding (PTB). Using comb-shaped planar waveguides, we achieve a full thickness (>10 mm) wound closure of porcine skin, which represents ~10-fold extension of the tissue area achieved with conventional PTB. The results point to a new direction in photomedicine for using light in deep tissues.

  2. Combining Fits of The Optical Photometry and X-ray Spectra of the Low Mass X-ray Binary V1408 Aquilae.

    NASA Astrophysics Data System (ADS)

    Gomez, Sebastian; Mason, Paul A.; Robinson, Edward L.

    2015-01-01

    V1408 Aquilae is a binary system with a black hole primary accreting matter from a low mass secondary. We observed the system at the McDonald Observatory and collected 126 hours of high speed optical photometry on the source. We modeled the optical light curve using the XRbinary light curve synthesis software. The best fits to the optical light curve seem to suggest that the primary is a low mass black hole, however we cannot exclude some high mass solutions. Our models slightly favor a 3 solar mass primary at an inclination of about 13 degrees. In order to further constrain these parameters, and verify their validity we compared the fits of the optical light curve to fits to the X-ray spectra of the source. Using data from the Chandra Transmission Grating Catalog and Archive and the ISIS software analysis package we modeled the spectra of the source with a multi-temperature blackbody for a relativistic accretion disk around a spinning black hole and an additional photon power law component. The fits to the optical lightcurve and X-ray spectra are in agreement, from this we conclude that the case for V1408 Aql to be at a low inclination and harbor a low mass black hole is plausible.

  3. Optical Characterization of Deep-Space Object Rotation States

    DTIC Science & Technology

    2014-09-01

    characterize non-resolvable object rotation states, focusing on objects well above low- Earth orbit altitudes. 3 OBSERVATIONS OF NON-RESOLVED ROTATING...OBJECTS This analysis focuses on broad-band temporal photometry of Earth -orbiting satellites (i.e., time-series measurements of whole-object...order. Upper-stages from rockets that have launched satellites into orbit represent one of the most common types of rotating object in Earth orbit

  4. Irregular Variability In Kepler Photometry

    NASA Astrophysics Data System (ADS)

    Schlecker, Martin

    2016-12-01

    The transit method is the most successful tool for exoplanet discovery to date. With more than half of all known exoplanets discovered by Kepler using this method, the mission also revealed a number of objects with dimming events that defy the common explanations, the most prominent being KIC 8462852 aka ``Tabby's star''. I embarked on a search for objects with such irregular transit signatures in the data of K2, the two-wheeled successor mission of Kepler. My method is a combination of automated pre-selection of targets showing downward flux excursions and visual light curve inspection of the selected subset comprising about SI{1.5}% of the initial sample. In addition, I developed a tool to constrain the effective temperature of a planet-hosting star from photometry alone. This software finds broad application in any science case where a photometric spectral type estimate is necessary. I used existing transit models and Bayesian inference to perform a Markov Chain Monte Carlo (MCMC) analysis of a planetary candidate I discovered. This putative gas giant is in a SI{1.32}day circular orbit with an exceptionally tight orbital radius of a ≈ 0.012 AU. My analysis revealed a scaled planetary radius of R_{p}/R_star = 0.0927±0.0026 and an edge-on orientation with an inclination i=89.8+3.0-3.4. EPIC 217393088.01 is one of the closest-orbiting exoplanets ever detected and the first giant planet with such a small orbital radius. An additional major finding of my search is EPIC 220262993, which exhibits aperiodic, asymmetric dips in flux with rapid dimming rates and up to SI{˜25}% depth, lasting for SIrange{2}{4} day. In previous works based on optical and mid-infrared photometry, this object was inconsistently classified as a possible quasar or a white dwarf. We conducted follow-up observations both photometrically with GROND on the MPI/ESO SI{2.2} meter telescope in La Silla (Chile) and spectroscopically with FIRE on the Magellan/Baade SI{6.5} meter telescope. With

  5. Galaxy Evolution from Deep Optical and Near-Infrared Surveys

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas Alexander

    1998-09-01

    We use very deep optical and near-infrared imaging surveys to set constraints on galaxy evolution models, based on the numbers, colors, and morphologies of infrared-excess galaxies that are found in the field. We concentrate on a curious population of extremely faint (K > 20) infrared-excess galaxies whose blue-optical colors are not consistent with the expectations of any passive evolution models. These ``faint red-outlier galaxies'' (FROGs) are distinct from the redder and brighter ``extremely red objects'' (EROs; R-K~=6 ). In a concerted effort to identify a good sample of FROG s and to study their properties, we used Keck/NIRC to image several independent high-galactic latitude fields. Much of the analysis presented here is drawn from a very deep 3.24 arcmin2 K-band ( Klim~24 at 3σ) mosaic in the deep Westphal HST/WFPC2 pointing of the Groth Survey Strip, for which F606W and F814W data were publically available. The surface density of FROGs is found to be ~ 3.3 +/- 1 arcmin-2, more than ten times that of EROs. Whereas reliable photometric redshifts are not forthcoming without the development of more relevant models, the colors are broadly consistent with the redshift range 1.2 < z < 2.3. If placed at z ~ 1.5, FROGs occur at space densities of about 10% of the local f* space density of K-selected galaxies. To map wavelength-dependent morphologies of two FROGs, we observed a portion of our main survey field with HST/NICMOS imaging through the F160W (1.6 μm) filter. The target was resolved into two r~=0''.6 objects with similar colors, separated by ~0''.7. This is suggestive of old and dynamically-relaxed systems. The colors of FROGs are not satisfactorily fit by dust-reddened Bruzual-Charlot models at any redshift and for a broad range of assumed star formation histories. The best possible fits are consistent with very large amounts of reddening, E(B - V) ~ 1. If the infrared-excess in EROs and FROGs is taken to be entirely due to the effects of dust, then we

  6. Optical processing deep inside optical materials using counterpropagating pulse-shaped spatial solitons

    NASA Astrophysics Data System (ADS)

    Hisaka, Masaki

    2016-10-01

    Optical processing using a pair of counterpropagating pulse-shaped spatial solitons to control the molecular structure deep inside an optical material is investigated. A femtosecond pulsed laser focused at the surface of a strontium barium niobate single crystal induces a pulse-shaped self-focusing second-harmonic beam. The two counterpropagating beams are involved in a head-on collision. Locally reversed crystal domains are formed at the collision point, assisted by external threshold controls such as crystal temperature and an electric dc field. The nonlinear interaction between the soliton collision and the approximate nonperiodic reversed domains induces a change in the second-harmonic intensity of the scattered and transmitted beams, thereby enabling the detection of locally reversed crystal domains.

  7. Active Optics for a Segmented Primary Mirror on a Deep-Space Optical Receiver Antenna (DSORA)

    NASA Technical Reports Server (NTRS)

    Clymer, B. D.

    1990-01-01

    This article investigates the active optical control of segments in the primary mirror to correct for wavefront errors in the Deep-Space Optical Receiver Antenna (DSORA). Although an exact assessment of improvement in signal blur radius cannot be made until a more detailed preliminary structural design is completed, analytical tools are identified for a time when such designs become available. A brief survey of appropriate sensing approaches is given. Since the choice of control algorithm and architecture depends on the particular sensing system used, typical control systems, estimated complexities, and the type of equipment required are discussed. Once specific sensor and actuator systems are chosen, the overall control system can be optimized using methods identified in the literature.

  8. Optical coherence tomography and optical coherence domain reflectometry for deep brain stimulation probe guidance

    NASA Astrophysics Data System (ADS)

    Jeon, Sung W.; Shure, Mark A.; Baker, Kenneth B.; Chahlavi, Ali; Hatoum, Nagi; Turbay, Massud; Rollins, Andrew M.; Rezai, Ali R.; Huang, David

    2005-04-01

    Deep Brain Stimulation (DBS) is FDA-approved for the treatment of Parkinson's disease and essential tremor. Currently, placement of DBS leads is guided through a combination of anatomical targeting and intraoperative microelectrode recordings. The physiological mapping process requires several hours, and each pass of the microelectrode into the brain increases the risk of hemorrhage. Optical Coherence Domain Reflectometry (OCDR) in combination with current methodologies could reduce surgical time and increase accuracy and safety by providing data on structures some distance ahead of the probe. For this preliminary study, we scanned a rat brain in vitro using polarization-insensitive Optical Coherence Tomography (OCT). For accurate measurement of intensity and attenuation, polarization effects arising from tissue birefringence are removed by polarization diversity detection. A fresh rat brain was sectioned along the coronal plane and immersed in a 5 mm cuvette with saline solution. OCT images from a 1294 nm light source showed depth profiles up to 2 mm. Light intensity and attenuation rate distinguished various tissue structures such as hippocampus, cortex, external capsule, internal capsule, and optic tract. Attenuation coefficient is determined by linear fitting of the single scattering regime in averaged A-scans where Beer"s law is applicable. Histology showed very good correlation with OCT images. From the preliminary study using OCT, we conclude that OCDR is a promising approach for guiding DBS probe placement.

  9. Additional optical photometry of the recurrent nova M31N 1990-10a during its 2016 eruption

    NASA Astrophysics Data System (ADS)

    Goranskij, V.; Barsukova, E.; Henze, M.

    2016-08-01

    We report additional optical measurements of the declining light curve of the recurrent nova M31N 1990-10a (see ATels #9276,#9280,#9281,#9383,#9386). All data were obtained with the 50-cm Maksutov meniscus telescope of the Crimean Astronomical Station of the Moscow University.

  10. Shape model of asteroid (130) Elektra from optical photometry and disk-resolved images from VLT/SPHERE and Nirc2/Keck

    NASA Astrophysics Data System (ADS)

    Hanuš, J.; Marchis, F.; Viikinkoski, M.; Yang, B.; Kaasalainen, M.

    2017-02-01

    Context. Asteroid (130) Elektra belongs to one of the six known triple asteroids in the main belt, so its mass has been reliably determined. Aims: We aim to use all available disk-resolved images of (130) Elektra obtained by the SPHERE instrument at VLT and by the Nirc2 of the Keck telescope together with the disk-integrated photometry to determine its shape model and its size. The volume can be then used in combination with the known mass to derive the bulk density of the primary. Methods: We have applied the All-Data Asteroid Modeling (ADAM) algorithm to the optical disk-integrated data, two disk-resolved images obtained by the SPHERE instrument, and 13 disk-resolved images from the Nirc2 of the Keck telescope. We have also derived the shape model and size of Elektra. Results: We present the shape model, volume-equivalent diameter (199 ± 7 km) and bulk density (1.60 ± 0.13 g cm-3) of the C-type asteroid Elektra.

  11. Doppler and range determination for deep space vehicles using active optical transponders

    NASA Technical Reports Server (NTRS)

    Kinman, Peter W.; Gagliardi, Robert M.

    1988-01-01

    This paper describes and analyzes two types of laser system employing active transponders that could accurately determine Doppler and range to deep space vehicles from earth-orbiting satellites. The first is a noncoherent optical system in which the Doppler effect on an intensity-modulating subcarrier is measured. The second is a coherent optical system in which the Doppler effect of the optical carrier itself is measured. Doppler and range measurement errors are mathematically modeled and, for three example systems, numerically evaluated.

  12. Photutils: Photometry tools

    NASA Astrophysics Data System (ADS)

    Bradley, Larry; Sipocz, Brigitta; Robitaille, Thomas; Tollerud, Erik; Deil, Christoph; Vinícius, Zè; Barbary, Kyle; Günther, Hans Moritz; Bostroem, Azalee; Droettboom, Michael; Bray, Erik; Bratholm, Lars Andersen; Pickering, T. E.; Craig, Matt; Pascual, Sergio; Greco, Johnny; Donath, Axel; Kerzendorf, Wolfgang; Littlefair, Stuart; Barentsen, Geert; D'Eugenio, Francesco; Weaver, Benjamin Alan

    2016-09-01

    Photutils provides tools for detecting and performing photometry of astronomical sources. It can estimate the background and background rms in astronomical images, detect sources in astronomical images, estimate morphological parameters of those sources (e.g., centroid and shape parameters), and perform aperture and PSF photometry. Written in Python, it is an affiliated package of Astropy (ascl:1304.002).

  13. Evaluation of Optical Magnitude of Deep Space Spacecraft

    NASA Astrophysics Data System (ADS)

    Wei, L.; Zheng-Hong, T.; Yong-da, L.

    2007-12-01

    Optical-electric technology can measure the tangential position and velocity of spacecraft. To know the feasibility of the use of optical-electric technology, it is necessary to estimate the magnitude of spacecraft first. Since the spacecrafts are non-self-illumination objects, the estimation formulas of the optical magnitude of spacecraft is constructed according to the radiation theory and the extra-atmospheric radiant emittance of the Sun in the visible light wave band. Taking Chang'e-1 as an example, the magnitude of it in different situations is calculated.

  14. Deep optical access on multi-core and multi-mode fiber for integrated wireless applications

    NASA Astrophysics Data System (ADS)

    Llorente, Roberto; Morant, Maria; Beltrán, Marta; Macho, Andrés.

    2015-01-01

    Deep integrated optical access networks target to provide great capillarity and multiple ONTs for cost- and energy-efficient pervasive connectivity seamless supporting integrated wireless. Several key optical technologies are herein reported supporting integrated deep optical access: Bundled radio-over-fiber transmission is proposed and demonstrated for the provision of quintuple-play services achieving 125 km SSMF optical reach. Bend-insensitive fiber in-building distribution is also proposed and demonstrated supporting joint legacy coaxial transmission. Multimode POF is also proposed and demonstrated suitable for joint in-building distribution of MATV and SMATV broadcasting signals. Optical comb technology us is also demonstrated suitable for mm-wave radio generation of multiband OFDM wireless signals. Finally, multicore fiber transmission is also proposed and demonstrated suitable for the transmission of LTE and WIMAX in wireless fronthaul applications in a minimized inter-core crosstalk penalty configuration.

  15. Andromeda (M31) optical and infrared disk survey. I. Insights in wide-field near-IR surface photometry

    SciTech Connect

    Sick, Jonathan; Courteau, Stéphane; Cuillandre, Jean-Charles; McDonald, Michael; De Jong, Roelof; Tully, R. Brent

    2014-05-01

    We present wide-field near-infrared J and K{sub s} images of the Andromeda Galaxy (M31) taken with WIRCam at the Canada-France-Hawaii Telescope as part of the Andromeda Optical and Infrared Disk Survey. This data set allows simultaneous observations of resolved stars and near-infrared (NIR) surface brightness across M31's entire bulge and disk (within R = 22 kpc), permitting a direct test of the stellar composition of near-infrared light in a nearby galaxy. Here we develop NIR observation and reduction methods to recover a uniform surface brightness map across the 3° × 1° disk of M31 with 27 WIRCam fields. Two sky-target nodding strategies are tested, and we find that strictly minimizing sky sampling latency cannot improve background subtraction accuracy to better than 2% of the background level due to spatio-temporal variations in the NIR skyglow. We fully describe our WIRCam reduction pipeline and advocate using flats built from night-sky images over a single night, rather than dome flats that do not capture the WIRCam illumination field. Contamination from scattered light and thermal background in sky flats has a negligible effect on the surface brightness shape compared to the stochastic differences in background shape between sky and galaxy disk fields, which are ∼0.3% of the background level. The most dramatic calibration step is the introduction of scalar sky offsets to each image that optimizes surface brightness continuity. Sky offsets reduce the mean surface brightness difference between observation blocks from 1% to <0.1% of the background level, though the absolute background level remains statistically uncertain to 0.15% of the background level. We present our WIRCam reduction pipeline and performance analysis to give specific recommendations for the improvement of NIR wide-field imaging methods.

  16. On the Absolute Age of the Metal-rich Globular M71 (NGC 6838). I. Optical Photometry

    NASA Astrophysics Data System (ADS)

    Di Cecco, A.; Bono, G.; Prada Moroni, P. G.; Tognelli, E.; Allard, F.; Stetson, P. B.; Buonanno, R.; Ferraro, I.; Iannicola, G.; Monelli, M.; Nonino, M.; Pulone, L.

    2015-08-01

    We investigated the absolute age of the Galactic globular cluster M71 (NGC 6838) using optical ground-based images (u\\prime ,g\\prime ,r\\prime ,i\\prime ,z\\prime ) collected with the MegaCam camera at the Canada-France-Hawaii Telescope (CFHT). We performed a robust selection of field and cluster stars by applying a new method based on the 3D (r\\prime ,u\\prime -g\\prime ,g\\prime -r\\prime ) color-color-magnitude diagram. A comparison between the color-magnitude diagram (CMD) of the candidate cluster stars and a new set of isochrones at the locus of the main sequence turn-off (MSTO) suggests an absolute age of 12 ± 2 Gyr. The absolute age was also estimated using the difference in magnitude between the MSTO and the so-called main sequence knee, a well-defined bending occurring in the lower main sequence. This feature was originally detected in the near-infrared bands and explained as a consequence of an opacity mechanism (collisionally induced absorption of molecular hydrogen) in the atmosphere of cool low-mass stars. The same feature was also detected in the r‧, u\\prime -g\\prime , and in the r\\prime ,g\\prime -r\\prime CMD, thus supporting previous theoretical predictions by Borysow et al. The key advantage in using the {{{Δ }}}{TO}{Knee} as an age diagnostic is that it is independent of uncertainties affecting the distance, the reddening, and the photometric zero point. We found an absolute age of 12 ± 1 Gyr that agrees, within the errors, with similar age estimates, but the uncertainty is on average a factor of two smaller. We also found that the {{{Δ }}}{TO}{Knee} is more sensitive to the metallicity than the MSTO, but the dependence vanishes when using the difference in color between the MSK and the MSTO.

  17. Heterochromatic flicker photometry.

    PubMed

    Bone, Richard A; Landrum, John T

    2004-10-15

    Measurement of the macular pigment optical density (MPOD) by heterochromatic flicker photometry (HFP) is accomplished by viewing a small circular stimulus that alternates between a test wavelength that is absorbed by the MP (typically--blue, 460 nm) and a reference wavelength that is not absorbed (typically-green, 540 nm). Flicker observed by the subject is reduced to a null point by adjusting the intensity of the former while viewing the stimulus centrally, and then peripherally. A higher intensity, I, of the blue component of the stimulus is needed under central viewing conditions owing to attenuation by the MP. The MPOD at the test wavelength is given by log (Icentral/Iperipheral). Variation of the test wavelength has been used to measure the MPOD spectrum. This in vitro MPOD spectrum matches that of the carotenoids present in the macular region of the retina and demonstrates the validity and specificity of this methodology. The distribution of MPOD in the retina can be determined with HFP using a series of annular stimuli of different diameters.

  18. Designing a Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material without a Structural Instability Problem.

    PubMed

    Zhao, Sangen; Kang, Lei; Shen, Yaoguo; Wang, Xiaodong; Asghar, Muhammad Adnan; Lin, Zheshuai; Xu, Yingying; Zeng, Siyuan; Hong, Maochun; Luo, Junhua

    2016-03-09

    A beryllium-free deep-ultraviolet (deep-UV) nonlinear optical (NLO) material K3Ba3Li2Al4B6O20F is developed mainly by the element substitution of Be for Al and Li from Sr2Be2B2O7 that was considered as one of the most promising deep-UV NLO materials. K3Ba3Li2Al4B6O20F preserves the structural merits of Sr2Be2B2O7 and thus exhibits no layering growth tendency and possesses the optical properties required for deep-UV NLO applications, including deep-UV transparency, phase-matchability, and sufficiently large second-harmonic generation (1.5 × KH2PO4). Furthermore, it overcomes the structural instability problem of Sr2Be2B2O7, which is confirmed by the obtainment of large single crystals and phonon dispersion calculations. These attributes make it very attractive for next-generation deep-UV NLO materials. The substitution of Be for Al and Li in beryllium borates provides a new opportunity to design beryllium-free deep-UV NLO materials with good performance.

  19. Design Reference Missions for Deep-Space Optical Communication

    NASA Astrophysics Data System (ADS)

    Breidenthal, J.; Abraham, D.

    2016-05-01

    We examined the potential, but uncertain, NASA mission portfolio out to a time horizon of 20 years, to identify mission concepts that potentially could benefit from optical communication, considering their communications needs, the environments in which they would operate, and their notional size, weight, and power constraints. A set of 12 design reference missions was selected to represent the full range of potential missions. These design reference missions span the space of potential customer requirements, and encompass the wide range of applications that an optical ground segment might eventually be called upon to serve. The design reference missions encompass a range of orbit types, terminal sizes, and positions in the solar system that reveal the chief system performance variables of an optical ground segment, and may be used to enable assessments of the ability of alternative systems to meet various types of customer needs.

  20. Pure and syndromic optic atrophy explained by deep intronic OPA1 mutations and an intralocus modifier.

    PubMed

    Bonifert, Tobias; Karle, Kathrin N; Tonagel, Felix; Batra, Marion; Wilhelm, Christian; Theurer, Yvonne; Schoenfeld, Caroline; Kluba, Torsten; Kamenisch, York; Carelli, Valerio; Wolf, Julia; Gonzalez, Michael A; Speziani, Fiorella; Schüle, Rebecca; Züchner, Stephan; Schöls, Ludger; Wissinger, Bernd; Synofzik, Matthis

    2014-08-01

    The genetic diagnosis in inherited optic neuropathies often remains challenging, and the emergence of complex neurological phenotypes that involve optic neuropathy is puzzling. Here we unravel two novel principles of genetic mechanisms in optic neuropathies: deep intronic OPA1 mutations, which explain the disease in several so far unsolved cases; and an intralocus OPA1 modifier, which explains the emergence of syndromic 'optic atrophy plus' phenotypes in several families. First, we unravelled a deep intronic mutation 364 base pairs 3' of exon 4b in OPA1 by in-depth investigation of a family with severe optic atrophy plus syndrome in which conventional OPA1 diagnostics including gene dosage analyses were normal. The mutation creates a new splice acceptor site resulting in aberrant OPA1 transcripts with retained intronic sequence and subsequent translational frameshift as shown by complementary DNA analysis. In patient fibroblasts we demonstrate nonsense mediated messenger RNA decay, reduced levels of OPA1 protein, and impairment of mitochondrial dynamics. Subsequent site-specific screening of >360 subjects with unexplained inherited optic neuropathy revealed three additional families carrying this deep intronic mutation and a base exchange four nucleotides upstream, respectively, thus confirming the clinical significance of this mutational mechanism. Second, in all severely affected patients of the index family, the deep intronic mutation occurred in compound heterozygous state with an exonic OPA1 missense variant (p.I382M; NM_015560.2). The variant alone did not cause a phenotype, even in homozygous state indicating that this long debated OPA1 variant is not pathogenic per se, but acts as a phenotypic modifier if it encounters in trans with an OPA1 mutation. Subsequent screening of whole exomes from >600 index patients identified a second family with severe optic atrophy plus syndrome due to compound heterozygous p.I382M, thus confirming this mechanism. In summary

  1. Quick acquisition and recognition method for the beacon in deep space optical communications.

    PubMed

    Wang, Qiang; Liu, Yuefei; Ma, Jing; Tan, Liying; Yu, Siyuan; Li, Changjiang

    2016-12-01

    In deep space optical communications, it is very difficult to acquire the beacon given the long communication distance. Acquisition efficiency is essential for establishing and holding the optical communication link. Here we proposed a quick acquisition and recognition method for the beacon in deep optical communications based on the characteristics of the deep optical link. To identify the beacon from the background light efficiently, we utilized the maximum similarity between the collecting image and the reference image for accurate recognition and acquisition of the beacon in the area of uncertainty. First, the collecting image and the reference image were processed by Fourier-Mellin. Second, image sampling and image matching were applied for the accurate positioning of the beacon. Finally, the field programmable gate array (FPGA)-based system was used to verify and realize this method. The experimental results showed that the acquisition time for the beacon was as fast as 8.1s. Future application of this method in the system design of deep optical communication will be beneficial.

  2. Accessing deep optical properties of skin using diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Koenig, Anne; Roig, Blandine; Le Digabel, Jimmy; Josse, Gwendal; Dinten, Jean-Marc

    2015-07-01

    Diffuse reflectance spectroscopy characterizes composition and structure of tissues by determining their scattering and absorption properties. We have developed in our laboratory a low-cost spatially resolved diffuse reflectance spectroscopy instrument. We present in this study some results showing how to adapt this technology on multi-layered tissues. First of all, a method enabling determination of scattering and absorption properties of multi-layered phantoms is described; the adaptation of the initial methodology to focus on deep layers is especially detailed. Then some preliminary results obtained on a panel of volunteer's redness faces are presented.

  3. Results from the Galileo Laser Uplink: A JPL Demonstration of Deep-Space Optical Communications

    NASA Technical Reports Server (NTRS)

    Wilson, K. E.; Lesh, J. R.

    1993-01-01

    The successful completion of the Galileo Optical Experiment (GOPEX), represented the accomplishment of a significant milestone in JPL's optical communication plan. The experiment demonstrated the first transmission of a narrow laser beam to a deep-space vehicle. Laser pulses were beamed to the Galileo spacecraft by Earth-based transmitters at the Table Mountain Facility (TMF), California, and Starfire Optical Range (SOR), New Mexico. The experiment took place over an eight-day period (December 9 through December 16, 1992) as Galileo receded from Earth on its way to Jupiter, and covered ranges from 1 to 6 million kilometers (15 times the Earth-Moon distance), the laser uplink from TMF covered the longest known range for laser beam transmission and detection. This demonstration is the latest in a series of accomplishments by JPL in the development of deep-space optical communications technology.

  4. Optical Survey with KMTNet for Dusty Star-Forming Galaxies in the Akari Deep Field South

    NASA Astrophysics Data System (ADS)

    Jeong, Woong-Seob; Ko, Kyeongyeon; Kim, Minjin; Ko, Jongwan; Kim, Sam; Pyo, Jeonghyun; Kim, Seong Jin; Kim, Taehyun; Seo, Hyun Jong; Park, Won-Kee; Park, Sung-Joon; Kim, Min Gyu; Kim, Dong Jin; Cha, Sang-Mok; Lee, Yongseok; Lee, Chung-Uk; Kim, Seung-Lee; Matsuura, Shuji; Pearson, Chris; Matsuhara, Hideo

    2016-10-01

    We present an optical imaging survey of AKARI Deep Field South (ADF-S) using the Korea Microlensing Telescope Network (KMTNet), to find optical counterparts of dusty star-forming galaxies. The ADF-S is a deep far-infrared imaging survey region with AKARI covering around 12 deg^2, where the deep optical imaging data are not yet available. By utilizing the wide-field capability of the KMTNet telescopes (˜4 deg^2), we obtain optical images in B, R and I bands for three regions. The target depth of images in B, R and I bands is ˜24 mag (AB) at 5σ, which enables us to detect most dusty star-forming galaxies discovered by AKARI in the ADF-S. Those optical datasets will be helpful to constrain optical spectral energy distributions as well as to identify rare types of dusty star-forming galaxies such as dust-obscured galaxy, sub-millimeter galaxy at high redshift.}

  5. Optical spectroscopy of laser plasma in a deep crater

    SciTech Connect

    Kononenko, Taras V; Konov, Vitalii I; Walter, D; Dausinger, F

    2009-04-30

    The time dynamics of plasma-emission spectra is studied experimentally at different stages of the drilling of a steel plate by 100-fs and 5-ps laser pulses: from a shallow crater to a hole. The change in the time dependence of the plasma temperature caused by variations in the irradiated surface geometry is analysed. It is found that the time interval needed to reach a particular temperature (about 8000 K) drastically increases from 40-50 to 150-200 ns when a specific crater depth is achieved. The opposite tendency is observed as the crater depth grows further and a hole is produced. Strong self-absorption in a plasma plume inside a deep crater is experimentally confirmed which results in the appearance of line absorption against a continuous emission spectrum. (interaction of laser radiation with matter. laser plasma)

  6. A deep-UV optical frequency comb at 205 nm.

    PubMed

    Peters, E; Diddams, S A; Fendel, P; Reinhardt, S; Hänsch, T W; Udem, Th

    2009-05-25

    By frequency quadrupling a picosecond pulse train from a Ti:sapphire laser at 820 nm we generate a frequency comb at 205 nm with nearly bandwidth-limited pulses. The nonlinear frequency conversion is accomplished by two successive frequency doubling stages that take place in resonant cavities that are matched to the pulse repetition rate of 82 MHz. This allows for an overall efficiency of 4.5 % and produces an output power of up to 70 mW for a few minutes and 25 mW with continuous operation for hours. Such a deep UV frequency comb may be employed for direct frequency comb spectroscopy in cases where it is less efficient to convert to these short wavelengths with continuous wave lasers.

  7. OAUNI photometry of ASASSN-16hw

    NASA Astrophysics Data System (ADS)

    Pereyra, A.; Ricra, J.; Zevallos, M.

    2016-09-01

    We report optical photometry of Type Ia SN ASASSN-16hw (=SN 2016ekt, ATel #9278, ATel #9289, ATel #9300) on 2016-08-06 (UT) gathered with the OAUNI 51cm telescope (Pereyra et al. 2015;arXiv:1512.03104) at Huancayo Observatory, Peru.

  8. Microwave analog fiber-optic link for use in the deep space network

    NASA Technical Reports Server (NTRS)

    Logan, R. T., Jr.; Lutes, G. F.; Maleki, L.

    1990-01-01

    A novel fiber-optic system with dynamic range of up to 150 dB-Hz for transmission of microwave analog signals is described. The design, analysis, and laboratory evaluations of this system are reported, and potential applications in the NASA/JPL Deep Space Network are discussed.

  9. Results from the DOLCE (Deep Space Optical Link Communications Experiment) project

    NASA Astrophysics Data System (ADS)

    Baister, Guy; Kudielka, Klaus; Dreischer, Thomas; Tüchler, Michael

    2009-02-01

    Oerlikon Space AG has since 1995 been developing the OPTEL family of optical communications terminals. The optical terminals within the OPTEL family have been designed so as to be able to position Oerlikon Space for future opportunities open to this technology. These opportunities range from commercial optical satellite crosslinks between geostationary (GEO) satellites, deep space optical links between planetary probes and the Earth, as well as optical links between airborne platforms (either between the airborne platforms or between a platform and GEO satellite). The OPTEL terminal for deep space applications has been designed as an integrated RF-optical terminal for telemetry links between the science probe and Earth. The integrated architecture provides increased TM link capacities through the use of an optical link, while spacecraft navigation and telecommand are ensured by the classical RF link. The optical TM link employs pulsed laser communications operating at 1058nm to transmit data using PPM modulation to achieve a robust link to atmospheric degradation at the optical ground station. For deep space links from Lagrange (L1 / L2) data rates of 10 - 20 Mbps can be achieved for the same spacecraft budgets (mass and power) as an RF high gain antenna. Results of an inter-island test campaign to demonstrate the performance of the pulsed laser communications subsystem employing 32-PPM for links through the atmosphere over a distance of 142 km are presented. The transmitter of the communications subsystem is a master oscillator power amplifier (MOPA) employing a 1 W (average power) amplifier and the receiver a Si APD with a measured sensitivity of -70.9 dBm for 32-PPM modulation format at a user data rate of 10 Mbps and a bit error rate (BER) of 10-6.

  10. Optical Photometry of Parsamian 21

    NASA Astrophysics Data System (ADS)

    Semkov, E. H.; Peneva, S. P.

    2010-05-01

    Results from BVRI photometric observations of the FUor-like object Parsamian 21 are presented. Calibrated BVRcIc magnitudes of the comparison star sequence around Parsamian 21 are given. Comparing our CCD photometric observations of Parsamian 21 in the period 2003 - 2009 with the data from Palomar plates showed no significant change in the brightness of the star for a very long period (57 years). Our conclusion is that Parsamian 21 is probably a member of the group of long-lived FUors and that the time-scale of the FUor phenomenon in some cases is much longer than that predicted in previous studies.

  11. Atomic force microscopy deep trench and sidewall imaging with an optical fiber probe

    SciTech Connect

    Xie, Hui Hussain, Danish; Yang, Feng; Sun, Lining

    2014-12-15

    We report a method to measure critical dimensions of micro- and nanostructures using the atomic force microscope (AFM) with an optical fiber probe (OFP). This method is capable of scanning narrow and deep trenches due to the long and thin OFP tip, as well as imaging of steep sidewalls with unique profiling possibilities by laterally tilting the OFP without any modifications of the optical lever. A switch control scheme is developed to measure the sidewall angle by flexibly transferring feedback control between the Z- and Y-axis, for a serial scan of the horizontal surface (raster scan on XY-plane) and sidewall (raster scan on the YZ-plane), respectively. In experiments, a deep trench with tapered walls (243.5 μm deep) and a microhole (about 14.9 μm deep) have been imaged with the orthogonally aligned OFP, as well as a silicon sidewall (fabricated by deep reactive ion etching) has been characterized with the tilted OFP. Moreover, the sidewall angle of TGZ3 (AFM calibration grating) was accurately measured using the switchable scan method.

  12. Atomic force microscopy deep trench and sidewall imaging with an optical fiber probe.

    PubMed

    Xie, Hui; Hussain, Danish; Yang, Feng; Sun, Lining

    2014-12-01

    We report a method to measure critical dimensions of micro- and nanostructures using the atomic force microscope (AFM) with an optical fiber probe (OFP). This method is capable of scanning narrow and deep trenches due to the long and thin OFP tip, as well as imaging of steep sidewalls with unique profiling possibilities by laterally tilting the OFP without any modifications of the optical lever. A switch control scheme is developed to measure the sidewall angle by flexibly transferring feedback control between the Z- and Y-axis, for a serial scan of the horizontal surface (raster scan on XY-plane) and sidewall (raster scan on the YZ-plane), respectively. In experiments, a deep trench with tapered walls (243.5 μm deep) and a microhole (about 14.9 μm deep) have been imaged with the orthogonally aligned OFP, as well as a silicon sidewall (fabricated by deep reactive ion etching) has been characterized with the tilted OFP. Moreover, the sidewall angle of TGZ3 (AFM calibration grating) was accurately measured using the switchable scan method.

  13. Potential of vortex beams with orbital angular momentum modulation for deep-space optical communication

    NASA Astrophysics Data System (ADS)

    Wang, Xiaorui; Liu, Yejun; Guo, Lei; Li, Hui

    2014-05-01

    In order to achieve multigigabit transmission in deep-space optical communication, our study applies a new modulation mode named orbital angular momentum (OAM) modulation, and uses the encoded OAM states of single photon as data information carriers, thus providing a reliable and high-speed transmission of signals. According to the long link characteristic of deep-space communication, we conduct a reasonable deployment for communication nodes in deep-space environment. First, we present the reliability of deep-space channel and analyze the data rate and spectral efficiency of beams with OAM. Second, we study the characteristics and generations of vortex beams with OAM by simulation. Results show that vortex beams have better spatial multiplexing capability of realizing high capacity data transmission. Finally, we propose an encoding method with OAM states of single photon. The transceiver units are based on spatial light modulators to perform the modulation and demodulation of vortex beams. At the receiver, the charged-coupled device camera is used to detect the signal intensity and decodes the OAM states. Our proposal not only ensures the confidentiality of deep-space optical communication, but also greatly increases the transmission rate.

  14. Transmission in near-infrared optical windows for deep brain imaging.

    PubMed

    Shi, Lingyan; Sordillo, Laura A; Rodríguez-Contreras, Adrián; Alfano, Robert

    2016-01-01

    Near-infrared (NIR) radiation has been employed using one- and two-photon excitation of fluorescence imaging at wavelengths 650-950 nm (optical window I) for deep brain imaging; however, longer wavelengths in NIR have been overlooked due to a lack of suitable NIR-low band gap semiconductor imaging detectors and/or femtosecond laser sources. This research introduces three new optical windows in NIR and demonstrates their potential for deep brain tissue imaging. The transmittances are measured in rat brain tissue in the second (II, 1,100-1,350 nm), third (III, 1,600-1,870 nm), and fourth (IV, centered at 2,200 nm) NIR optical tissue windows. The relationship between transmission and tissue thickness is measured and compared with the theory. Due to a reduction in scattering and minimal absorption, window III is shown to be the best for deep brain imaging, and windows II and IV show similar but better potential for deep imaging than window I.

  15. Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

    PubMed

    Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

    2016-04-15

    A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

  16. Structure and photometry of an I less than 20.5 galaxy sample from the Hubble Space Telescope medium deep survey

    NASA Astrophysics Data System (ADS)

    Phillips, Andrew C.; Bershady, Matthew A.; Forbes, Duncan A.; Koo, David C.; Illingworth, Garth D.; Reitzel, David B.; Griffiths, Richard E.; Windhorst, Rogier A.

    1995-05-01

    A set of 100 faint galaxies from nine Hubble Space Telescope (HST) Wide Field Camera (WFC) I-band images have been analyzed as part of the Medium Deep Survey (MDS) Key Project. This sample reaches a depth of I approximately less than or equal to 20.5 (corresponding to B approximately 22-23) and complements the first set of fainter galaxies analyzed by the MDS team. Images were deconvolved using the Lucy-Richardson algorithm and a newly developed procedure designed to yield a more reliable determination of structure in the low-S/N regime. These deconvolved images were used to characterize the structure of the galaxies through quantative measurements of total magnitudes, half-light radii, exponential disk scale lengths, and disk-to-total rations. Extensive testing was done to establish the validity of the procedures used and to characterize the degree of systematic errors present in the analysis techniques. The observed size-magnitude distribution appears consistent with a scenario in which luminous galaxies have evolved little in intrinsic luminosity, size, or structure over recent epochs in a 'normal' cosmology (0 less than q0 less than 0.5 and Lambda0 = 0). The predicted nonevolving distributions were based on models designed to fit existing counts, colors, and redshifts of faint galaxies and on the observed correlations between metric rest-frame size and luminosity found in a nearby galaxy sample studied by Kent (1984-1985). The typical galaxy in our sample is expected to be at z approximately equal to 0.3, and to have a luminosity approximately 0.5 mag fainter than L* and a half-light radius of approximately 1 sec or approximately 6 kpc (H 0 = 50 km/s Mpc). The observed distribution of disk-to-total ratios, while uncertain, is in agreement with that of Kent's sample and thus supports the view that substantial evolution has not occurred over the look-back times characteristic of our sample.

  17. TFIT: Mixed-resolution data set photometry package

    NASA Astrophysics Data System (ADS)

    Laidler, Victoria G.; Papovich, Casey; Grogin, Norman A.; Idzi, Rafal; Dickinson, Mark; Ferguson, Henry C.; Hilbert, Bryan; Clubb, Kelsey; Ravindranath, Swara

    2015-05-01

    TFIT measures galaxy photometry using prior knowledge of sources in a deep, high-resolution image (HRI) to improve photometric measurements of objects in a corresponding low-resolution image (LRI) of the same field, usually at a different wavelength. For background-limited data, this technique produces optimally weighted photometry that maximizes signal-to-noise ratio (S/N). For objects not significantly detected in the low-resolution image, it provides useful and quantitative information for setting upper limits.

  18. THE MULTIWAVELENGTH SURVEY BY YALE-CHILE (MUSYC): DEEP MEDIUM-BAND OPTICAL IMAGING AND HIGH-QUALITY 32-BAND PHOTOMETRIC REDSHIFTS IN THE ECDF-S

    SciTech Connect

    Cardamone, Carolin N.; Van Dokkum, Pieter G.; Urry, C. Megan; Brammer, Gabriel; Taniguchi, Yoshi; Gawiser, Eric; Bond, Nicholas; Taylor, Edward; Damen, Maaike; Treister, Ezequiel; Cobb, Bethany E.; Schawinski, Kevin; Lira, Paulina; Murayama, Takashi; Saito, Tomoki; Sumikawa, Kentaro

    2010-08-15

    We present deep optical 18-medium-band photometry from the Subaru telescope over the {approx}30' x 30' Extended Chandra Deep Field-South, as part of the Multiwavelength Survey by Yale-Chile (MUSYC). This field has a wealth of ground- and space-based ancillary data, and contains the GOODS-South field and the Hubble Ultra Deep Field. We combine the Subaru imaging with existing UBVRIzJHK and Spitzer IRAC images to create a uniform catalog. Detecting sources in the MUSYC 'BVR' image we find {approx}40,000 galaxies with R {sub AB} < 25.3, the median 5{sigma} limit of the 18 medium bands. Photometric redshifts are determined using the EAzY code and compared to {approx}2000 spectroscopic redshifts in this field. The medium-band filters provide very accurate redshifts for the (bright) subset of galaxies with spectroscopic redshifts, particularly at 0.1 < z < 1.2 and at z {approx}> 3.5. For 0.1 < z < 1.2, we find a 1{sigma} scatter in {Delta}z/(1 + z) of 0.007, similar to results obtained with a similar filter set in the COSMOS field. As a demonstration of the data quality, we show that the red sequence and blue cloud can be cleanly identified in rest-frame color-magnitude diagrams at 0.1 < z < 1.2. We find that {approx}20% of the red sequence galaxies show evidence of dust emission at longer rest-frame wavelengths. The reduced images, photometric catalog, and photometric redshifts are provided through the public MUSYC Web site.

  19. Hubble and Spitzer Follow-up for Two Strongly Lensed LBGs: (I) Optical-to-Mid-IR Photometry and Mid-IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Tucker, Douglas Lee; Allam, S. S.; SDSS Bright Arcs Search Team

    2009-05-01

    We present the HST and Spitzer photometry and Spitzer spectroscopy of two strongly lensed Lyman Break Galaxies LBGs that were recently discovered. These two LBGs -- the "8 O'Clock Arc" (Allam et al. 2007) and the "SDSS J1206+5142 Arc" (Lin et al. 2008)-- are currently the brightest known LBGs, roughly 3 times brighter than the former record-holder, MS1512-cB58 (a.k.a. "cB58").

  20. QDPHOT: Quick & Dirty PHOTometry

    NASA Astrophysics Data System (ADS)

    Mighell, Kenneth

    2016-01-01

    QDPHOT is a fast CCD stellar photometry task which quickly produces CCD stellar photometry from two CCD images of a star field. It was designed to be a data mining tool for finding high-quality stellar observations in the data archives of the National Virtual Observatory. QDPHOT typically takes just a few seconds to analyze two Hubble Space Telescope WFPC2 observations of Local Group star clusters. It is also suitable for real-time data-quality analysis of CCD observations; on-the-fly instrumental color-magnitude diagrams can be produced at the telescope console during the few seconds between CCD readouts.

  1. Development of composite fiber-optic electric-power umbilical cable and optical feedthrough for deep ocean mining

    NASA Astrophysics Data System (ADS)

    Mitsui, T.; Gomi, T.; Ito, T.; Ushitani, S.; Yamaguchi, M.

    The development of mining systems for mineral resources from deep ocean floors is now progressing in many countries. In Japan, the Agency of Industrial Science and Technology, has conducted research and development for a manganese nodule mining system. In this project, it is planned to use a new composite fiber-optic electric power umbilical cable for electrical power and control signal transmission from a main vessel to subsea equipment such as lifting pumps and collecting devices at about 5,000 meters' depth. The umbilical cable system is required to have good resistance to repetitive bending, twisting, and other external forces and to be able to withstand water pressure of up to 550kgf/sq cm. A 100m long sample umbilical cable, electrical connectors, and optical feedthroughs for this system have been developed and successfully passed mechanical, electrical, and optical tests.

  2. Deep optical imaging of tissue using the second and third near-infrared spectral windows.

    PubMed

    Sordillo, Laura A; Pu, Yang; Pratavieira, Sebastião; Budansky, Yury; Alfano, Robert R

    2014-05-01

    Light at wavelengths in the near-infrared (NIR) region allows for deep penetration and minimal absorption through high scattering tissue media. NIR light has been conventionally used through the first NIR optical tissue window with wavelengths from 650 to 950 nm. Longer NIR wavelengths had been overlooked due to major water absorption peaks and a lack of NIR-CCD detectors. The second NIR spectral window from 1100 to 1350 nm and a new spectral window from 1600 to 1870 nm, known as the third NIR optical window, were investigated. Optical attenuation measurements from thin tissue slices of normal and malignant breast and prostate tissues, pig brain, and chicken tissue were obtained in the spectral range from 400 to 2500 nm. Optical images of chicken tissue overlying three black wires were also obtained using the second and third spectral windows. Due to a reduction in scattering and minimal absorption, longer attenuation lengths and clearer optical images could be seen in the second and third NIR optical windows compared to the conventional first NIR optical window. A possible fourth optical window centered at 2200 nm was noted.

  3. Unusual Long and Luminous Optical Transient in the Subaru Deep Field

    NASA Astrophysics Data System (ADS)

    Urata, Yuji; Tsai, Patrick P.; Huang, Kuiyun; Morokuma, Tomoki; Yasuda, Naoki; Tanaka, Masaomi; Motohara, Kentaro; Hayashi, Masao; Kashikawa, Nobunari; Ly, Chun; Malkan, Matthew A.

    2012-11-01

    We present observations of SDF-05M05, an unusual optical transient discovered in the Subaru Deep Field (SDF). The duration of the transient is > ~ 800 days in the observer frame, and the maximum brightness during observation reached approximately 23 mag in the i' and z' bands. The faint host galaxy is clearly identified in all five optical bands of the deep SDF images. The photometric redshift of the host yields z ~ 0.6 and the corresponding absolute magnitude at maximum is ~ - 20. This implies that this event shone with an absolute magnitude brighter than -19 mag for approximately 300 days in the rest frame, which is significantly longer than a typical supernova and ultraluminous supernova. The total radiated energy during our observation was 1 × 1051 erg. The light curves and color evolution are marginally consistent with some luminous IIn supernovae. We suggest that the transient may be a unique and peculiar supernova at intermediate redshift.

  4. Photodamage in deep tissue two-photon optical biopsy of human skin.

    PubMed

    Dalbosco, Luca; Zanini, Giulia; D'Amato, Elvira; Tessarolo, Francesco; Boi, Sebastiana; Bauer, Paolo; Haase, Albrecht; Antolini, Renzo

    2015-10-01

    Photodamage, induced by femtosecond laser radiation, was studied in thick samples of human skin tissue (healthy skin and neoplastic lesions). Photobleaching, photoionization, and thermomechanical damage effects were characterized comparatively. The laser power dependence of the damage rates allowed to connect macroscopic effects to underlying molecular processes. Optical effects were correlated to histopathological changes. Tissue alterations were found only from thermomechanical cavitation and limited to superficial layers of the epidermis. From the depth-dependencies of all damage thresholds a depth-dependent power-compensation scheme was defined allowing for damage-free deep tissue optical biopsy. Damage-induced luminescence pattern for different excitation powers and a corresponding threshold analysis.

  5. Deep-space Optical Terminals (DOT) Ground Laser Transmitter (GLT) Trades and Conceptual Point Design

    NASA Astrophysics Data System (ADS)

    Roberts, W. T.; Wright, M. W.

    2010-11-01

    A conceptual design for the Deep-space Optical Terminals (DOT) Ground Laser Transmitter (GLT) has been developed. Two trade studies were performed: one to determine the most cost-effective uplink pointing system including the use of multiple and single apertures, and the second to determine the optimal type of laser transmitter for use as a beacon reference source. The baselined design resulting from the trade studies incorporated a single 1-m aperture capable of 16-microrad pointing accuracy with multiple fiber-laser sources providing up to 5 kW average optical power at 1030 nm.

  6. A Plan for the Development and Demonstration of Optical Communications for Deep Space

    NASA Technical Reports Server (NTRS)

    Lesh, J. R.; Deutsch, L. J.; Weber, W. J.

    1990-01-01

    In this article, an overall plan for the development and demonstration of optical communications for deep-space applications is presented. The current state of the technology for optical communications is presented. Then, the development and demonstration plan is presented in two parts: the overall major systems activities, followed by the generic technology developments that will enable them. The plan covers the path from laboratory subsystems demonstrations out to a full-scale flight experiment system for the proposed Mars Communications Relay Orbiter mission.

  7. A ten-meter optical telescope for deep-space communications

    NASA Technical Reports Server (NTRS)

    Shaik, Kamran; Kerr, Edwin L.

    1990-01-01

    Optical communications using laser light in the visible spectral range is being considered for future deep-space missions. Such a system will require a large telescope in earth vicinity to be used as a receiving station for data return from the spacecraft. A preliminary discussion for a ground-based receiving station consisting of a 10-meter hexagonally segmented primary with high surface tolerance and a unique sunshade is presented.

  8. Modulation techniques for deep-space pulse-position modulation (PPM) optical communication

    NASA Technical Reports Server (NTRS)

    Rayman, Marc D.; Robinson, Deborah L.

    1988-01-01

    The extremely energy-efficient pulse-position modulation (PPM) format is being actively developed as a basis for optical communications with deep-space probes. Attention is presently given to different modulation schemes for the efficient production of laser pulses over a broad range of repetition rates. Both Q-switching and cavity dumping modulation methods are available for the envisioned diode-pumped Nd:YAG laser source. Numerical calculation results are presented for cavity-dumping.

  9. Deep-UV Based Acousto-Optic Tunable Filter for Spectral Sensing Applications

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.

    2006-01-01

    In this paper, recent progress made in the development of quartz and KDP crystal based acousto-optic tunable filters (AOTF) are presented. These AOTFs are developed for operation over deep-UV to near-UV wavelengths of 190 nm to 400 nm. Preliminary output performance measurements of quartz AOTF and design specifications of KDP AOTF are presented. At 355 nm, the quartz AOTF device offered approx.15% diffraction efficiency with a passband full-width-half-maximum (FWHM) of less than 0.0625 nm. Further characterization of quartz AOTF devices at deep-UV wavelengths is progressing. The hermetic packaging of KDP AOTF is nearing completion. The solid-state optical sources being used for excitation include nonlinear optics based high-energy tunable UV transmitters that operate around 320 nm and 308 nm wavelengths, and a tunable deep-UV laser operating over 193 nm to 210 nm. These AOTF devices have been developed as turn-key devices for primarily for space-based chemical and biological sensing applications using laser induced Fluorescence and resonance Raman techniques.

  10. Deep optical observations of the central X-ray source in the Puppis A supernova remnant

    NASA Astrophysics Data System (ADS)

    Mignani, R. P.; de Luca, A.; Mereghetti, S.; Caraveo, P. A.

    2009-06-01

    Context: X-ray observations revealed a group of radio-silent isolated neutron stars (INSs) at the centre of young supernova remnants (SNRs), dubbed central compact objects or CCOs, with properties different from those of classical rotation-powered pulsars. In at least three cases, evidence points towards CCOs being low-magnetized INSs, born with slow rotation periods, and possibly accreting from a debris disc of material formed out of the supernova event. Understanding the origin of the diversity of the CCOs can shed light on supernova explosion and neutron star formation models. Optical/infrared (IR) observations are crucial to test different CCO interpretations. Aims: The aim of our work is to perform a deep optical investigation of the CCO RX J0822.0-4300 in the Puppis A SNR, one of the most poorly understood in the CCO family. Methods: By using as a reference the Chandra X-ray coordinates of RX J0822.0-4300 we performed deep optical observations in the B, V and I bands with the Very Large Telescope (VLT). Results: We found no candidate optical counterpart within 3 σ of the computed Chandra X-ray position down to 5 σ limits of B ~ 27.2, V ~ 26.9, and I ~ 25.6, the deepest obtained in the optical band for this source. Conclusions: These limits confirm the non-detection of a companion brighter than an M 5 dwarf. At the same time, they do not constrain optical emission from the neutron star surface, while emission from the magnetosphere would require a spectral break in the optical/IR. Based on observations collected at ESO, Paranal, under Programme 78.D-0706(A).

  11. Optical tracking of deep-space spacecraft in Halo L2 orbits and beyond: The Gaia mission as a pilot case

    NASA Astrophysics Data System (ADS)

    Buzzoni, Alberto; Altavilla, Giuseppe; Galleti, Silvia

    2016-04-01

    We tackle the problem of accurate optical tracking of distant man-made probes, on Halo orbit around the Earth-Sun libration point L2 and beyond, along interplanetary transfers. The improved performance of on-target tracking, especially when observing with small-class telescopes is assessed providing a general estimate of the expected S/N ratio in spacecraft detection. The on-going GAIA mission is taken as a pilot case for our analysis, reporting on fresh literature and original optical photometry and astrometric results. The probe has been located, along its projected nominal path, with quite high precision, within 0.13±0.09 arcsec, or 0.9±0.6 km. Spacecraft color appears to be red, with (V -Rc) =1.1±0.2 and a bolometric correction to the Rc band of (Bol -Rc) = -1.1±0.2 . The apparent magnitude, Rc =20.8±0.2 , is much fainter than originally expected. These features lead to suggest a lower limit for the Bond albedo α =0.11±0.05 and confirm that incident Sun light is strongly reddened by GAIA through its on-board MLI blankets covering the solar shield. Relying on the GAIA figures, we found that VLT-class telescopes could yet be able to probe distant spacecraft heading Mars, up to 30 million km away, while a broader optical coverage of the forthcoming missions to Venus and Mars could be envisaged, providing to deal with space vehicles of minimum effective area A ⩾106 cm2. In addition to L2 surveys, 2 m-class telescopes could also effectively flank standard radar-ranging techniques in deep-space probe tracking along Earth's gravity-assist maneuvers for interplanetary missions.

  12. A Ten-Meter Ground-Station Telescope for Deep-Space Optical Communications: A Preliminary Design

    NASA Technical Reports Server (NTRS)

    Britcliffe, M.; Hoppe, D.; Roberts, W.; Page, N.

    2001-01-01

    This article describes a telescope design for a 10-m optical ground station for deep-space communications. The design for a direct-detection optical communications telescope differs dramatically from a telescope for imaging applications. In general, the requirements for optical manufacturing and tracking performance are much less stringent for direct detection of optical signals. The technical challenge is providing a design that will operate in the daytime/nighttime conditions required for a Deep Space Network tracking application. The design presented addresses these requirements. The design will provide higher performance at lower cost than existing designs.

  13. The Metal Abundances across Cosmic Time (MACT) Survey. I. Optical Spectroscopy in the Subaru Deep Field

    NASA Astrophysics Data System (ADS)

    Ly, Chun; Malhotra, Sangeeta; Malkan, Matthew A.; Rigby, Jane R.; Kashikawa, Nobunari; de los Reyes, Mithi A.; Rhoads, James E.

    2016-09-01

    Deep rest-frame optical spectroscopy is critical for characterizing and understanding the physical conditions and properties of the ionized gas in galaxies. Here, we present a new spectroscopic survey called “Metal Abundances across Cosmic Time” or { M }{ A }{ C }{ T }, which will obtain rest-frame optical spectra for ˜3000 emission-line galaxies. This paper describes the optical spectroscopy that has been conducted with MMT/Hectospec and Keck/DEIMOS for ≈1900 z = 0.1-1 emission-line galaxies selected from our narrowband and intermediate-band imaging in the Subaru Deep Field. In addition, we present a sample of 164 galaxies for which we have measured the weak [O iii]λ4363 line (66 with at least 3σ detections and 98 with significant upper limits). This nebular emission line determines the gas-phase metallicity by measuring the electron temperature of the ionized gas. This paper presents the optical spectra, emission-line measurements, interstellar properties (e.g., metallicity, gas density), and stellar properties (e.g., star formation rates, stellar mass). Paper II of the { M }{ A }{ C }{ T } survey (Ly et al.) presents the first results on the stellar mass-gas metallicity relation at z ≲ 1 using the sample with [O iii]λ4363 measurements.

  14. Architectural design of a ground-based deep-space optical reception antenna

    NASA Technical Reports Server (NTRS)

    Kerr, E. L.

    1989-01-01

    An architectural design of a ground-based antenna (telescope) for receiving optical communications from deep space is presented. Physical and optical parameters, and their effect on the performance and cost considerations, are described. The channel capacity of the antenna is 100 kbits/s from Saturn and 5 Mbits/s from Mars. A novel sunshade is designed to permit optical communication even when the deep-space laser source is as close to the sun as 12 deg. Inserts in the tubes of the sunshade permit operations at solar elongations as small as 6 or 3 deg. The Nd:YAG source laser and the Fraunhofer filter (a narrow-band predetection optical filter) are tuned to match the Doppler shifts of the source and background. A typical Saturn-to-earth data link can reduce its source power requirement from 8.2 W to 2 W of laser output by employing a Fraunhofer filter instead of a conventional multilayer dielectric filter.

  15. Main-Reflector Manufacturing Technology for the Deep Space Optical Communications Ground Station

    NASA Astrophysics Data System (ADS)

    Britcliffe, M. J.; Hoppe, D. J.

    2001-01-01

    The Deep Space Network (DSN) has plans to develop a 10-m-diameter optical communications receiving station. The system uses the direct detection technique, which has much different requirements from a typical astronomical telescope. The receiver must operate in daylight and nighttime conditions. This imposes special requirements on the optical system to reject stray light from the Sun and other sources. One of the biggest challenges is designing a main-reflector surface that meets these requirements and can be produced at a reasonable cost. The requirements for the performance of the reflector are presented. To date, an aspherical primary reflector has been assumed. A reflector with a spherical reflector has a major cost advantage over an aspherical design, with no sacrifice in performance. A survey of current manufacturing techniques for optical mirrors of this type was performed. Techniques including solid glass, lightweight glass, diamond-turned aluminum, and composite mirrors were investigated.

  16. Smart optical coherence tomography for ultra-deep imaging through highly scattering media.

    PubMed

    Badon, Amaury; Li, Dayan; Lerosey, Geoffroy; Boccara, A Claude; Fink, Mathias; Aubry, Alexandre

    2016-11-01

    Multiple scattering of waves in disordered media is a nightmare whether it is for detection or imaging purposes. So far, the best approach to get rid of multiple scattering is optical coherence tomography. This basically combines confocal microscopy and coherence time gating to discriminate ballistic photons from a predominant multiple scattering background. Nevertheless, the imaging-depth range remains limited to 1 mm at best in human soft tissues because of aberrations and multiple scattering. We propose a matrix approach of optical imaging to push back this fundamental limit. By combining a matrix discrimination of ballistic waves and iterative time reversal, we show, both theoretically and experimentally, an extension of the imaging-depth limit by at least a factor of 2 compared to optical coherence tomography. In particular, the reported experiment demonstrates imaging through a strongly scattering layer from which only 1 reflected photon out of 1000 billion is ballistic. This approach opens a new route toward ultra-deep tissue imaging.

  17. Three-dimensional deep sub-wavelength defect detection using λ = 193 nm optical microscopy.

    PubMed

    Barnes, Bryan M; Sohn, Martin Y; Goasmat, Francois; Zhou, Hui; Vladár, András E; Silver, Richard M; Arceo, Abraham

    2013-11-04

    Optical microscopy is sensitive both to arrays of nanoscale features and to their imperfections. Optimizing scattered electromagnetic field intensities from deep sub-wavelength nanometer scale structures represents an important element of optical metrology. Current, well-established optical methods used to identify defects in semiconductor patterning are in jeopardy by upcoming sub-20 nm device dimensions. A novel volumetric analysis for processing focus-resolved images of defects is presented using simulated and experimental examples. This new method allows defects as narrow as (16 ± 2) nm (k = 1) to be revealed using 193 nm light with focus and illumination conditions optimized for three-dimensional data analysis. Quantitative metrics to compare two-dimensional and three-dimensional imaging indicate possible fourfold improvements in sensitivity using these methods.

  18. Optical variability and pigment biomass in the Sargasso Sea as determined using deep-sea optical mooring data

    NASA Technical Reports Server (NTRS)

    Smith, R. C.; Waters, K. J.; Baker, K. S.

    1991-01-01

    A 9-month time series of optical data, composed of three separate deployments, from the Biowatt 1987 deep-sea mooring located in the oligotrophic waters of the Sargasso Sea at 32 deg N, 70 deg W, is presented. These data were analyzed using several biooptical models for the purpose of providing a continuous estimate of the spectral diffuse attenuation coefficient and pigment biomass. Results of the first 70-day deployment demonstrate the utility of optical observations as proxy measures of biological parameters, and facilitate a preliminary analysis of the temporal variations and a comparison of the present biooptical observations with concurrent physical observations. Biooptical properties exhibit variation in response to physical forcings, such as diel variations of incident solar irradiance, episodic wind forcing, advective mesoscale eddy layer depth, and succession of phytoplankton. The mooring data are discussed in the context of contemporaneous shipboard observations as well as in terms of future ocean satellite observations.

  19. Surface Photometry of NGC 4656/4657

    SciTech Connect

    Stayton, L.C.; Angione, R.J.; Talbert, F.D.

    1983-05-01

    An analysis by surface photometry of the galaxy system NGC 4656/4657 yields the following results. First, NGC 4656 and NGC 4657 appear to be parts of the same galaxy. Second, the system bears a strong resemblance to both the SMC and NGC 55. Third, although the outermost isophotes in B and G light show coincidences with radio continuum, we found no conclusive optical indications of an interaction with the galaxy NGC 4631.

  20. Optical Photometry of the Type Ia Supernova 1999ee and the Type Ib/c Supernova 1999ex in IC 5179

    NASA Astrophysics Data System (ADS)

    Stritzinger, Maximilian; Hamuy, Mario; Suntzeff, Nicholas B.; Smith, R. C.; Phillips, M. M.; Maza, José; Strolger, L.-G.; Antezana, Roberto; González, Luis; Wischnjewsky, Marina; Candia, Pablo; Espinoza, Juan; González, David; Stubbs, Christopher; Becker, A. C.; Rubenstein, Eric P.; Galaz, Gaspar

    2002-10-01

    We present UBVRIz light curves of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both located in the galaxy IC 5179. SN 1999ee has an extremely well-sampled light curve spanning from 10 days before Bmax through 53 days after peak. Near maximum, we find systematic differences of ~0.05 mag in photometry measured with two different telescopes, even though the photometry is reduced to the same local standards around the supernova using the specific color terms for each instrumental system. We use models for our bandpasses and spectrophotometry of SN 1999ee to derive magnitude corrections (S-corrections) and remedy this problem. This exercise demonstrates the need of accurately characterizing the instrumental system before great photometric accuracies of Type Ia supernovae can be claimed. It also shows that this effect can have important astrophysical consequences, since a small systematic shift of 0.02 mag in the B-V color can introduce a 0.08 mag error in the extinction-corrected peak B magnitude of a supernova and thus lead to biased cosmological parameters. The data for the Type Ib/c SN 1999ex present us with the first ever observed shock breakout of a supernova of this class. These observations show that shock breakout occurred 18 days before Bmax and support the idea that Type Ib/c supernovae are due to the core collapse of massive stars rather than thermonuclear disruption of white dwarfs.

  1. DOLPHOT: Stellar photometry

    NASA Astrophysics Data System (ADS)

    Dolphin, Andrew

    2016-08-01

    DOLPHOT is a stellar photometry package that was adapted from HSTphot for general use. It supports two modes; the first is a generic PSF-fitting package, which uses analytic PSF models and can be used for any camera. The second mode uses ACS PSFs and calibrations, and is effectively an ACS adaptation of HSTphot. A number of utility programs are also included with the DOLPHOT distribution, including basic image reduction routines.

  2. Third Workshop on Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William J. (Editor); Lasher, Lawrence E. (Editor)

    2001-01-01

    The discoveries of extrasolar planets by Wolszczan, Mayor and Queloz, Butler et al., and others have stimulated a widespread effort to obtain a body of data sufficient to understand their occurrence and characteristics. Doppler velocity techniques have found dozens of extrasolar planets with masses similar to that of Jupiter. Approximately ten percent of the stars that show planets with orbital periods of a few days to a week are expected to show transits. With the mass obtained from Doppler velocity measurements and the size from transit photometry, the densities of the planets can be determined. Theoretical models of the structure of "hot Jupiters" (i.e., those planets within a tenth of an astronomical unit (AU) of the parent star) indicate that these planets should be substantially larger in size and lower in density than Jupiter. Thus the combination of transit and Doppler velocity measurements provide a critical test of the theories of planetary structure. Furthermore, because photometry can be done with small-aperture telescopes rather than requiring the use of much larger telescopes, transit photometry should also reduce the cost of discovering extrasolar planets.

  3. Experimental Evaluation of Optically Polished Aluminum Panels on the Deep Space Network's 34 Meter Antenna

    NASA Technical Reports Server (NTRS)

    Vilnrotter, V.

    2011-01-01

    The potential development of large aperture ground?based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation is to polish the aluminum reflector panels of 34?meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by state of?the?art polished aluminum panels. Theoretical analyses of receiving antenna pointing, temporal synchronization and data detection have been addressed in previous papers. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. Two polished aluminum panels (a standard DSN panel polished to high reflectance, and a custom designed aluminum panel with much better surface quality) have been mounted on the 34 meter research antenna at Deep?Space Station 13 (DSS?13), and a remotely controlled CCD camera with a large CCD sensor in a weather?proof container has been installed next to the subreflector, pointed directly at the custom polished panel. The point?spread function (PSF) generated by the Vertex polished panel has been determined to be smaller than the sensor of the CCD camera, hence a detailed picture of the PSF can be obtained every few seconds, and the sensor array data processed to determine the center of the intensity distribution. In addition to estimating the center coordinates, expected communications performance can also been evaluated with the recorded data. The results of preliminary pointing experiments with the Vertex polished panel receiver using the planet Jupiter to simulate the PSF generated by a deep?space optical transmitter are presented and discussed in this paper.

  4. Near Earth Architectural Options for a Future Deep Space Optical Communications Network

    NASA Technical Reports Server (NTRS)

    Edwards, B. L.; Liebrecht, P. E.; Fitzgerald, R. J.

    2004-01-01

    In the near future the National Aeronautics and Space Administration anticipates a significant increase in demand for long-haul communications services from deep space to Earth. Distances will range from 0.1 to 40 AU, with data rate requirements in the 1's to 1000's of Mbits/second. The near term demand is driven by NASA's Space Science Enterprise which wishes to deploy more capable instruments onboard spacecraft and increase the number of deep space missions. The long term demand is driven by missions with extreme communications challenges such as very high data rates from the outer planets, supporting sub-surface exploration, or supporting NASA's Human Exploration and Development of Space Enterprise beyond Earth orbit. Laser communications is a revolutionary communications technology that will dramatically increase NASA's ability to transmit information across the solar system. Lasercom sends information using beams of light and optical elements, such as telescopes and optical amplifiers, rather than RF signals, amplifiers, and antennas. This paper provides an overview of different network options at Earth to meet NASA's deep space lasercom requirements. It is based mainly on work done for the Mars Laser Communications Demonstration Project, a joint project between NASA's Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory, California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL). It reports preliminary conclusions from the Mars Lasercom Study conducted at MIT/LL and on additional work done for the Tracking and Data Relay Satellite System Continuation Study at GSFC. A lasercom flight terminal will be flown on the Mars Telesat Orbiter (MTO) to be launched by NASA in 2009, and will be the first high rate deep space demonstration of this revolutionary technology.

  5. Accretion and Magnetic Reconnection in the Pre-Main Sequence Binary DQ Tau as Revealed through High-Cadence Optical Photometry

    NASA Astrophysics Data System (ADS)

    Tofflemire, Benjamin M.; Mathieu, Robert D.; Ardila, David R.; Akeson, Rachel L.; Ciardi, David R.; Herczeg, Gregory; Johns-Krull, Christopher M.; Vodniza, Alberto

    2016-01-01

    Protostellar disks are integral to the formation and evolution of low-mass stars and planets. A paradigm for the star-disk interaction has been extensively developed through theory and observation in the case of single stars. Most stars, however, form in binaries or higher order systems where the distribution of disk material and mass flows are more complex. Pre-main sequence (PMS) binary stars can have up to three accretion disks: two circumstellar disks and a circumbinary disk separated by a dynamically cleared gap. Theory suggests that mass may periodically flow in an accretion stream from a circumbinary disk across the gap onto circumstellar disks or stellar surfaces.The archetype for this theory is the eccentric, PMS binary DQ Tau. Moderate-cadence broadband photometry (~10 observations per orbital period) has shown pulsed brightening events near most periastron passages, just as numerical simulations would predict for a binary of similar orbital parameters. While this observed behavior supports the accretion stream theory, it is not exclusive to variable accretion rates. Magnetic reconnection events (flares) during the collision of stellar magnetospheres at periastron (when separated by 8 stellar radii) could produce the same periodic, broadband behavior when observed at a one-day cadence. Further evidence for magnetic activity comes from gyrosynchrotron, radio flares (typical of stellar flares) observed near multiple periastron passages. To reveal the physical mechanism seen in DQ Tau's moderate-cadence observations, we have obtained continuous, moderate-cadence, multi-band photometry over 10 orbital periods (LCOGT 1m network), supplemented with 32 nights of minute-cadence photometry centered on 4 separate periastron passages (WIYN 0.9m; APO ARCSAT). With detailed lightcurve morphologies we distinguish between the gradual rise and fall on multi-day time-scales predicted by the accretion stream theory and the hour time-scale, rapid-rise and exponential

  6. A wideband connection to sperm whales: A fiber-optic, deep-sea hydrophone array

    NASA Astrophysics Data System (ADS)

    Heerfordt, Anders; Møhl, Bertel; Wahlberg, Magnus

    2007-03-01

    A 10-element, 950 m long, vertical hydrophone array based on fiber-optic data transmission has been developed primarily for studying the beam pattern from deep diving cetaceans emitting sonar pulses. The array elements have a configurable sampling rate and resolution with a maximum signal bandwidth of 90 kHz and a maximum dynamic range of 133 dB. The array has been deployed from a 14 m ketch with a crew of four. In the course of the development a number of mechanical and electrical problems have been solved.

  7. Earth-Image Tracking in the IR for Deep Space Optical Communications

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Chen, Yinging; Lee, Shinhak; Ortiz, Gerard G.

    2005-01-01

    Sub-microradian level laser beam pointing to an Earth-based receiver is required for deep space optical communications. This requires a beacon emanated from Earth towards the spacecraft. The beacon could be a laser or reflected sunlight from Earth. Earth image tracking in the visible is hampered by significant albedo variations and/or crescent Earth image yielding large central errors. Here, we report results of Earth-image tracking in the infrared (8 to 13 micron) region of the spectrum with the aim of substantially alleviating the two challenges mentioned earlier.

  8. In vivo deep tissue imaging using wavefront shaping optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Yu, Hyeonseung; Lee, Peter; Lee, KyeoReh; Jang, Jaeduck; Lim, Jaeguyn; Jang, Wooyoung; Jeong, Yong; Park, YongKeun

    2016-10-01

    Multiple light scattering in tissue limits the penetration of optical coherence tomography (OCT) imaging. Here, we present in vivo OCT imaging of a live mouse using wavefront shaping (WS) to enhance the penetration depth. A digital micromirror device was used in a spectral-domain OCT system for complex WS of an incident beam which resulted in the optimal delivery of light energy into deep tissue. Ex vivo imaging of chicken breasts and mouse ear tissues showed enhancements in the strength of the image signals and the penetration depth, and in vivo imaging of the tail of a live mouse provided a multilayered structure inside the tissue.

  9. Routing of deep-subwavelength optical beams without reflection and diffraction using infinitely anisotropic metamaterials

    NASA Astrophysics Data System (ADS)

    Catrysse, Peter B.; Fan, Shanhui

    2015-03-01

    Media that are described by extreme electromagnetic parameters, such as very large/small permittivity/permeability, have generated significant fundamental and applied interest in recent years. Notable examples include epsilon-near-zero, ultra-low refractive-index, and ultra-high refractive-index materials. Many photonic structures, such as waveguides, lenses, and photonic band gap materials, benefit greatly from the large index contrast provided by such media. In this paper, I discuss our recent work on media with infinite anisotropy, i.e., infinite permittivity (permeability) in one direction and finite in the other directions. As an illustration of the unusual optical behaviors that result from infinite anisotropy, I describe efficient light transport in deep-subwavelength apertures filled with infinitely anisotropic media. I then point out some of the opportunities that exist for controlling light at the nano-scale using infinitely anisotropic media by themselves. First, I show that a single medium with infinite anisotropy enables diffraction-free propagation of deep-subwavelength beams. Next, I demonstrate interfaces between two infinitely anisotropic media that are impedancematched for complete deep-subwavelength beams and enable reflection-free routing with zero bend radius that is entirely free from diffraction effects even when deep-subwavelength information is encoded on the beams. These behaviors indicate an unprecedented possibility to use media with infinite anisotropy to manipulate beams with deepsubwavelength features, including complete images. To illustrate physical realizability, I demonstrate a metamaterial design using existing materials in a planar geometry, which can be implemented using well-established nanofabrication techniques. This approach provides a path to deep-subwavelength routing of information-carrying beams and far-field imaging unencumbered by diffraction and reflection.

  10. Optical focusing deep inside dynamic scattering media with near-infrared time-reversed ultrasonically encoded (TRUE) light

    PubMed Central

    Liu, Yan; Lai, Puxiang; Ma, Cheng; Xu, Xiao; Grabar, Alexander A.; Wang, Lihong V.

    2015-01-01

    Focusing light deep inside living tissue has not been achieved despite its promise to play a central role in biomedical imaging, optical manipulation and therapy. To address this challenge, internal-guide-star-based wavefront engineering techniques—for example, time-reversed ultrasonically encoded (TRUE) optical focusing—were developed. The speeds of these techniques, however, were limited to no greater than 1 Hz, preventing them from in vivo applications. Here we improve the speed of optical focusing deep inside scattering media by two orders of magnitude, and focus diffuse light inside a dynamic scattering medium having a speckle correlation time as short as 5.6 ms, typical of living tissue. By imaging a target, we demonstrate the first focusing of diffuse light inside a dynamic scattering medium containing living tissue. Since the achieved focusing speed approaches the tissue decorrelation rate, this work is an important step towards in vivo deep tissue noninvasive optical imaging, optogenetics and photodynamic therapy. PMID:25556918

  11. Precision Multiband Photometry with a DSLR Camera

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Bakos, G. Á.; Penev, K.; Csubry, Z.; Hartman, J. D.; Bhatti, W.; de Val-Borro, M.

    2016-03-01

    Ground-based exoplanet surveys such as SuperWASP, HAT Network of Telescopes (HATNet), and KELT have discovered close to two hundred transiting extrasolar planets in the past several years. The strategy of these surveys is to look at a large field of view and measure the brightnesses of its bright stars to around half a percent per point precision, which is adequate for detecting hot Jupiters. Typically, these surveys use CCD detectors to achieve high precision photometry. These CCDS, however, are expensive relative to other consumer-grade optical imaging devices, such as digital single-lens reflex cameras (DSLRs). We look at the possibility of using a DSLR camera for precision photometry. Specifically, we used a Canon EOS 60D camera that records light in three colors simultaneously. The DSLR was integrated into the HATNet survey and collected observations for a month, after which photometry was extracted for 6600 stars in a selected stellar field. We found that the DSLR achieves a best-case median absolute deviation of 4.6 mmag per 180 s exposure when the DSLR color channels are combined, and 1000 stars are measured to better than 10 mmag (1%). Also, we achieve 10 mmag or better photometry in the individual colors. This is good enough to detect transiting hot Jupiters. We performed a candidate search on all stars and found four candidates, one of which is KELT-3b, the only known transiting hot Jupiter in our selected field. We conclude that the Canon 60D is a cheap, lightweight device capable of useful photometry in multiple colors.

  12. Deep sea tests of a prototype of the KM3NeT digital optical module

    NASA Astrophysics Data System (ADS)

    Adrián-Martínez, S.; Ageron, M.; Aharonian, F.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; de Asmundis, R.; Balasi, K.; Band, H.; Barbarino, G.; Barbarito, E.; Barbato, F.; Baret, B.; Baron, S.; Belias, A.; Berbee, E.; van den Berg, A. M.; Berkien, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Bianucci, S.; Billault, M.; Birbas, A.; Boer Rookhuizen, H.; Bormuth, R.; Bouché, V.; Bouhadef, B.; Bourlis, G.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Caruso, F.; Cecchini, S.; Ceres, A.; Cereseto, R.; Champion, C.; Château, F.; Chiarusi, T.; Christopoulou, B.; Circella, M.; Classen, L.; Cocimano, R.; Colonges, S.; Coniglione, R.; Cosquer, A.; Costa, M.; Coyle, P.; Creusot, A.; Curtil, C.; Cuttone, G.; D'Amato, C.; D'Amico, A.; De Bonis, G.; De Rosa, G.; Deniskina, N.; Destelle, J.-J.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Drury, L.; Durand, D.; Eberl, T.; Eleftheriadis, C.; Elsaesser, D.; Enzenhöfer, A.; Fermani, P.; Fusco, L. A.; Gajana, D.; Gal, T.; Galatà, S.; Gallo, F.; Garufi, F.; Gebyehu, M.; Giordano, V.; Gizani, N.; Gracia Ruiz, R.; Graf, K.; Grasso, R.; Grella, G.; Grmek, A.; Habel, R.; van Haren, H.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Herold, B.; Hevinga, M. A.; van der Hoek, M.; Hofestädt, J.; Hogenbirk, J.; Hugon, C.; Hößl, J.; Imbesi, M.; James, C.; Jansweijer, P.; Jochum, J.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Kappos, E.; Katz, U.; Kavatsyuk, O.; Keller, P.; Kieft, G.; Koffeman, E.; Kok, H.; Kooijman, P.; Koopstra, J.; Korporaal, A.; Kouchner, A.; Koutsoukos, S.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lattuada, D.; Le Provost, H.; Leisos, A.; Lenis, D.; Leonora, E.; Lindsey Clark, M.; Liolios, A.; Llorens Alvarez, C. D.; Löhner, H.; Lo Presti, D.; Louis, F.; Maccioni, E.; Mannheim, K.; Manolopoulos, K.; Margiotta, A.; Mariş, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Masullo, R.; Michael, T.; Migliozzi, P.; Migneco, E.; Miraglia, A.; Mollo, C.; Mongelli, M.; Morganti, M.; Mos, S.; Moudden, Y.; Musico, P.; Musumeci, M.; Nicolaou, C.; Nicolau, C. A.; Orlando, A.; Orzelli, A.; Papageorgiou, K.; Papaikonomou, A.; Papaleo, R.; Păvălaş, G. E.; Peek, H.; Pellegrino, C.; Pellegriti, M. G.; Perrina, C.; Petridou, C.; Piattelli, P.; Pikounis, K.; Popa, V.; Pradier, Th.; Priede, M.; Pühlhofer, G.; Pulvirenti, S.; Racca, C.; Raffaelli, F.; Randazzo, N.; Rapidis, P. A.; Razis, P.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rovelli, A.; Royon, J.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Santangelo, A.; Sapienza, P.; Savvidis, I.; Schmelling, J.; Schnabel, J.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Siotis, I.; Sipala, V.; Solazzo, M.; Spitaleri, A.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stolarczyk, T.; Stransky, D.; Taiuti, M.; Terreni, G.; Tézier, D.; Théraube, S.; Thompson, L. F.; Timmer, P.; Trapierakis, H. I.; Trasatti, L.; Trovato, A.; Tselengidou, M.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Vernin, P.; Viola, S.; Vivolo, D.; Werneke, P.; Wiggers, L.; Wilms, J.; de Wolf, E.; van Wooning, R. H. L.; Yatkin, K.; Zachariadou, K.; Zonca, E.; Zornoza, J. D.; Zúñiga, J.; Zwart, A.

    2014-09-01

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same $^{40}$K decay and the localization bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions.

  13. Acquisition, Tracking, and Pointing Using Earth Thermal Images for Deep Space Optical Communications

    NASA Technical Reports Server (NTRS)

    Ortiz, Gerry G.; Lee, Shinhak

    2003-01-01

    The feasibility of using long wavelength Earth thermal (infrared) images for telescope tracking/pointing application. for both Deep Space Free- pace Optical Communications has been investigated and is reported her. The advantage of this technology rests on using full Earth images in this band, which yield more accurate estimates of geometric centroids than that of Earth images in the visible band. Another major advantage is that these images are nearly independent of Earth phase angle. The results of the study show that at a Mars range, with currently available sensors, a noise equivalent angle of 10 to 150 nanoradians and a bias error of better than 80 nanoradians can be obtained. This enables precise pointing of the optical communications beam for high data rate links.

  14. Fluoride antireflection coatings for deep ultraviolet optics deposited by ion-beam sputtering.

    PubMed

    Yoshida, Toshiya; Nishimoto, Keiji; Sekine, Keiichi; Etoh, Kazuyuki

    2006-03-01

    Optically high quality coatings of fluoride materials are required in deep ultraviolet (DUV) lithography. We have applied ion-beam sputtering (IBS) to obtain fluoride films with smooth surfaces. The extinction coefficients were of the order of 10(-4) at the wavelength of 193 nm due to the reduction of their absorption loss. The transmittance of the MgF2/GdF3 antireflection coating was as high as 99.7% at the wavelength of 193 nm. The surfaces of the IBS deposited films were so smooth that the surface roughness of the A1F3/GdF3 film was comparable with that of the CaF2 substrate. The MgF2/GdF3 coating fulfilled the temperature and humidity requirements of military specification. Thus, the IBS deposited fluoride films are promising candidate for use in the DUV lithography optics.

  15. Deep-subwavelength imaging of both electric and magnetic localized optical fields by plasmonic campanile nanoantenna

    DOE PAGES

    Caselli, Niccolò; La China, Federico; Bao, Wei; ...

    2015-06-05

    Tailoring the electromagnetic field at the nanoscale has led to artificial materials exhibiting fascinating optical properties unavailable in naturally occurring substances. Besides having fundamental implications for classical and quantum optics, nanoscale metamaterials provide a platform for developing disruptive novel technologies, in which a combination of both the electric and magnetic radiation field components at optical frequencies is relevant to engineer the light-matter interaction. Thus, an experimental investigation of the spatial distribution of the photonic states at the nanoscale for both field components is of crucial importance. Here we experimentally demonstrate a concomitant deep-subwavelength near-field imaging of the electric and magneticmore » intensities of the optical modes localized in a photonic crystal nanocavity. We take advantage of the “campanile tip”, a plasmonic near-field probe that efficiently combines broadband field enhancement with strong far-field to near-field coupling. In conclusion, by exploiting the electric and magnetic polarizability components of the campanile tip along with the perturbation imaging method, we are able to map in a single measurement both the electric and magnetic localized near-field distributions.« less

  16. Deep-subwavelength imaging of both electric and magnetic localized optical fields by plasmonic campanile nanoantenna

    SciTech Connect

    Caselli, Niccolò; La China, Federico; Bao, Wei; Riboli, Francesco; Gerardino, Annamaria; Li, Lianhe; Linfield, Edmund H.; Pagliano, Francesco; Fiore, Andrea; Schuck, P. James; Cabrini, Stefano; Weber-Bargioni, Alexander; Gurioli, Massimo; Intonti, Francesca

    2015-06-05

    Tailoring the electromagnetic field at the nanoscale has led to artificial materials exhibiting fascinating optical properties unavailable in naturally occurring substances. Besides having fundamental implications for classical and quantum optics, nanoscale metamaterials provide a platform for developing disruptive novel technologies, in which a combination of both the electric and magnetic radiation field components at optical frequencies is relevant to engineer the light-matter interaction. Thus, an experimental investigation of the spatial distribution of the photonic states at the nanoscale for both field components is of crucial importance. Here we experimentally demonstrate a concomitant deep-subwavelength near-field imaging of the electric and magnetic intensities of the optical modes localized in a photonic crystal nanocavity. We take advantage of the “campanile tip”, a plasmonic near-field probe that efficiently combines broadband field enhancement with strong far-field to near-field coupling. In conclusion, by exploiting the electric and magnetic polarizability components of the campanile tip along with the perturbation imaging method, we are able to map in a single measurement both the electric and magnetic localized near-field distributions.

  17. Predicting Global Minimum in Complex Beryllium Borate System for Deep-ultraviolet Functional Optical Applications

    PubMed Central

    Bian, Qiang; Yang, Zhihua; Wang, Ying; Cao, Chao; Pan, Shilie

    2016-01-01

    Searching for high performance materials for optical communication and laser industry in deep-ultraviolet (DUV) region has been the subject of considerable interest. Such materials by design from scratching on multi-component complex crystal systems are challenging. Here, we predict, through density function calculations and unbiased structure searching techniques, the formation of quaternary NaBeBO3 compounds at ambient pressure. Among the four low-energy phases, the P63/m structure exhibits a DUV cutoff edge of 20 nm shorter than α-BaB2O4 (189 nm) – the best-known DUV birefringent material. While the P-6 structure exhibits one time second-harmonic generation efficiency of KH2PO4 and possesses excellent crystal growth habit without showing any layer habit as observed in the only available DUV nonlinear optical material KBe2BO3F2, whose layer habit limits its wide industrial applications. These NaBeBO3 structures are promising candidates for the next generation of DUV optical materials, and the structure prediction technique will shed light on future optical materials design. PMID:27734901

  18. Predicting Global Minimum in Complex Beryllium Borate System for Deep-ultraviolet Functional Optical Applications

    NASA Astrophysics Data System (ADS)

    Bian, Qiang; Yang, Zhihua; Wang, Ying; Cao, Chao; Pan, Shilie

    2016-10-01

    Searching for high performance materials for optical communication and laser industry in deep-ultraviolet (DUV) region has been the subject of considerable interest. Such materials by design from scratching on multi-component complex crystal systems are challenging. Here, we predict, through density function calculations and unbiased structure searching techniques, the formation of quaternary NaBeBO3 compounds at ambient pressure. Among the four low-energy phases, the P63/m structure exhibits a DUV cutoff edge of 20 nm shorter than α-BaB2O4 (189 nm) – the best-known DUV birefringent material. While the P-6 structure exhibits one time second-harmonic generation efficiency of KH2PO4 and possesses excellent crystal growth habit without showing any layer habit as observed in the only available DUV nonlinear optical material KBe2BO3F2, whose layer habit limits its wide industrial applications. These NaBeBO3 structures are promising candidates for the next generation of DUV optical materials, and the structure prediction technique will shed light on future optical materials design.

  19. Deep-subwavelength imaging of both electric and magnetic localized optical fields by plasmonic campanile nanoantenna

    PubMed Central

    Caselli, Niccolò; La China, Federico; Bao, Wei; Riboli, Francesco; Gerardino, Annamaria; Li, Lianhe; Linfield, Edmund H.; Pagliano, Francesco; Fiore, Andrea; Schuck, P. James; Cabrini, Stefano; Weber-Bargioni, Alexander; Gurioli, Massimo; Intonti, Francesca

    2015-01-01

    Tailoring the electromagnetic field at the nanoscale has led to artificial materials exhibiting fascinating optical properties unavailable in naturally occurring substances. Besides having fundamental implications for classical and quantum optics, nanoscale metamaterials provide a platform for developing disruptive novel technologies, in which a combination of both the electric and magnetic radiation field components at optical frequencies is relevant to engineer the light-matter interaction. Thus, an experimental investigation of the spatial distribution of the photonic states at the nanoscale for both field components is of crucial importance. Here we experimentally demonstrate a concomitant deep-subwavelength near-field imaging of the electric and magnetic intensities of the optical modes localized in a photonic crystal nanocavity. We take advantage of the “campanile tip”, a plasmonic near-field probe that efficiently combines broadband field enhancement with strong far-field to near-field coupling. By exploiting the electric and magnetic polarizability components of the campanile tip along with the perturbation imaging method, we are able to map in a single measurement both the electric and magnetic localized near-field distributions. PMID:26045401

  20. Interior radiances in optically deep absorbing media. 3: Scattering from Haze L

    NASA Technical Reports Server (NTRS)

    Kattawar, G. W.; Plass, G. N.

    1974-01-01

    The interior radiances are calculated within an optically deep absorbing medium scattering according to the Haze L phase function. The dependence on the solar zenith angle, the single scattering albedo, and the optical depth within the medium is calculated by the matrix operator method. The development of the asymptotic angular distribution of the radiance in the diffusion region is illustrated through a number of examples; it depends only on the single scattering albedo and on the phase function for single scattering. The exact values of the radiance in the diffusion region are compared with values calculated from the approximate equations proposed by Van de Hulst. The variation of the radiance near the lower boundary of an optically thick medium is illustrated with examples. The attenuation length is calculated for various single scattering albedos and compared with the corresponding values for Rayleigh scattering. The ratio of the upward to the downward flux is found to be remarkably constant within the medium. The heating rate is calculated and found to have a maximum value at an optical depth of two within a Haze L layer when the sun is at the zenith.

  1. Deep-space and near-Earth optical communications by coded orbital angular momentum (OAM) modulation.

    PubMed

    Djordjevic, Ivan B

    2011-07-18

    In order to achieve multi-gigabit transmission (projected for 2020) for the use in interplanetary communications, the usage of large number of time slots in pulse-position modulation (PPM), typically used in deep-space applications, is needed, which imposes stringent requirements on system design and implementation. As an alternative satisfying high-bandwidth demands of future interplanetary communications, while keeping the system cost and power consumption reasonably low, in this paper, we describe the use of orbital angular momentum (OAM) as an additional degree of freedom. The OAM is associated with azimuthal phase of the complex electric field. Because OAM eigenstates are orthogonal the can be used as basis functions for N-dimensional signaling. The OAM modulation and multiplexing can, therefore, be used, in combination with other degrees of freedom, to solve the high-bandwidth requirements of future deep-space and near-Earth optical communications. The main challenge for OAM deep-space communication represents the link between a spacecraft probe and the Earth station because in the presence of atmospheric turbulence the orthogonality between OAM states is no longer preserved. We will show that in combination with LDPC codes, the OAM-based modulation schemes can operate even under strong atmospheric turbulence regime. In addition, the spectral efficiency of proposed scheme is N2/log2N times better than that of PPM.

  2. Deep brain optical measurements of cell type-specific neural activity in behaving mice.

    PubMed

    Cui, Guohong; Jun, Sang Beom; Jin, Xin; Luo, Guoxiang; Pham, Michael D; Lovinger, David M; Vogel, Steven S; Costa, Rui M

    2014-01-01

    Recent advances in genetically encoded fluorescent sensors enable the monitoring of cellular events from genetically defined groups of neurons in vivo. In this protocol, we describe how to use a time-correlated single-photon counting (TCSPC)-based fiber optics system to measure the intensity, emission spectra and lifetime of fluorescent biosensors expressed in deep brain structures in freely moving mice. When combined with Cre-dependent selective expression of genetically encoded Ca(2+) indicators (GECIs), this system can be used to measure the average neural activity from a specific population of cells in mice performing complex behavioral tasks. As an example, we used viral expression of GCaMPs in striatal projection neurons (SPNs) and recorded the fluorescence changes associated with calcium spikes from mice performing a lever-pressing operant task. The whole procedure, consisting of virus injection, behavior training and optical recording, takes 3-4 weeks to complete. With minor adaptations, this protocol can also be applied to recording cellular events from other cell types in deep brain regions, such as dopaminergic neurons in the ventral tegmental area. The simultaneously recorded fluorescence signals and behavior events can be used to explore the relationship between the neural activity of specific brain circuits and behavior.

  3. Deep proton writing: a powerful rapid prototyping technology for various micro-optical components

    NASA Astrophysics Data System (ADS)

    Van Erps, Jürgen; Vervaeke, Michael; Debaes, Christof; Ottevaere, Heidi; Van Overmeire, Sara; Hermanne, Alex; Thienpont, Hugo

    2010-05-01

    One of the important challenges for the deployment of the emerging breed of nanotechnology components is interfacing them with the external world, preferably accomplished with low-cost micro-optical devices. For the fabrication of this kind of micro-optical modules, we make use of deep proton writing (DPW) as a generic rapid prototyping technology. DPW consists of bombarding polymer samples with swift protons, which results after chemical processing steps in high quality micro-optical components. The strength of the DPW micro-machining technology is the ability to fabricate monolithic building blocks that include micro-optical and mechanical functionalities which can be precisely integrated into more complex photonic systems. In this paper we give an overview of the process steps of the technology and we present several examples of micro-optical and micro-mechanical components, fabricated through DPW, targeting applications in optical interconnections and in bio-photonics. These include: high-precision 2-D fiber connectors, out-of-plane coupling structures featuring high-quality 45° and curved micro-mirrors, arrays of high aspect ratio micro-pillars, and fluorescence and absorption detection bio-photonics modules. While DPW is clearly not a mass fabrication technique as such, one of its assets is that once the master component has been prototyped, a metal mould can be generated from the DPW master by applying electroplating. After removal of the plastic master, this metal mould can be used as a shim in a final microinjection moulding or hot embossing step. This way, the master component can be mass-produced at low cost in a wide variety of high-tech plastics.

  4. Remote-Sensing Reflectance and Inherent Optical Properties for Optically Deep Waters: A Revisit

    NASA Technical Reports Server (NTRS)

    Lee, Zhong-Ping; Carder, Kendall L.; Du, Ke-Ping

    2001-01-01

    Remote-sensing reflectance (r(rs)) is defined as the ratio of upwelling radiance to downwelling irradiance. Relationships between remote-sensing reflectance and inherent optical properties serve as the basis for ocean-color modeling, as well as for spectral deduction of oceanic constituents through analytical/semi-analytical models of ocean color. A decade ago, a simple and concise formula based on Monte Carlo simulations was developed by relating rrs to a property u, the ratio of backscattering (b(b)) to the sum of absorption (a) and backscattering (u = b(b)/(a+b(b))). This relationship generally ignored the shape differences in phase functions between molecular scattering and particle scattering. In this study, the relationship is updated with separate parameters for molecular and particle scattering, based on the Radiative Transfer Equation through use of Hydrolight numerical solutions. The new approach fits r(rs) better than an earlier traditional formula, for both clear and turbid waters.

  5. Deep optical imaging of the γ-ray pulsar J1048-5832 with the VLT

    NASA Astrophysics Data System (ADS)

    Danilenko, A.; Kirichenko, A.; Sollerman, J.; Shibanov, Yu.; Zyuzin, D.

    2013-04-01

    Context. PSR J1048-5832 is a young radio-pulsar that has recently been detected in γ-rays with Fermi, and also in X-rays with Chandra and XMM-Newton. It powers a compact pulsar wind nebula visible in X-rays and is in many ways similar to the Vela pulsar. Aims: We present deep optical observations made with the ESO Very Large Telescope to search for optical counterparts of the pulsar and its nebula and to explore their multi-wavelength emission properties. Methods: The data were obtained in the V and R bands and were compared with archival data in other spectral domains. Results: We do not detect the pulsar in the optical and derive informative upper limits of R ≳ 28.m1 and V ≳ 28.m4 for its brightness. Using a red-clump star method, we estimate an interstellar extinction towards the pulsar of AV ≈ 2 mag, which is consistent with the absorbing column density derived from X-rays. The respective distance agrees with the dispersion measure distance. We reanalysed the Chandra X-ray data and compared the dereddened upper limits with the unabsorbed X-ray spectrum of the pulsar. We find that regarding its optical-X-ray spectral properties this γ-ray pulsar is not distinct from other pulsars detected in both ranges. However, like the Vela pulsar, it is very inefficient in the optical and X-rays. Among a dozen optical sources overlapping with the pulsar X-ray nebula we find one with V ≈ 26.m9 and R ≈ 26.m3, whose colour is slightly bluer than that of the field stars and is consistent with the peculiar colours typical for pulsar nebula features. It positionally coincides with a relatively bright feature of the pulsar X-ray nebula, resembling the Crab wisp and is located in ~2 from the pulsar. We suggest this source as a counterpart candidate to the feature. Conclusions: Based on the substantial interstellar extinction towards the pulsar and its optical inefficiency, additional optical studies should be carried out at longer wavelengths. Based on observations made

  6. Smart optical coherence tomography for ultra-deep imaging through highly scattering media

    PubMed Central

    Badon, Amaury; Li, Dayan; Lerosey, Geoffroy; Boccara, A. Claude; Fink, Mathias; Aubry, Alexandre

    2016-01-01

    Multiple scattering of waves in disordered media is a nightmare whether it is for detection or imaging purposes. So far, the best approach to get rid of multiple scattering is optical coherence tomography. This basically combines confocal microscopy and coherence time gating to discriminate ballistic photons from a predominant multiple scattering background. Nevertheless, the imaging-depth range remains limited to 1 mm at best in human soft tissues because of aberrations and multiple scattering. We propose a matrix approach of optical imaging to push back this fundamental limit. By combining a matrix discrimination of ballistic waves and iterative time reversal, we show, both theoretically and experimentally, an extension of the imaging-depth limit by at least a factor of 2 compared to optical coherence tomography. In particular, the reported experiment demonstrates imaging through a strongly scattering layer from which only 1 reflected photon out of 1000 billion is ballistic. This approach opens a new route toward ultra-deep tissue imaging. PMID:27847864

  7. Deep-subwavelength Nanometric Image Reconstruction using Fourier Domain Optical Normalization.

    PubMed

    Qin, Jing; Silver, Richard M; Barnes, Bryan M; Zhou, Hui; Dixson, Ronald G; Henn, Mark-Alexander

    Quantitative optical measurements of deep sub-wavelength, three-dimensional, nanometric structures with sensitivity to sub-nanometer details address an ubiquitous measurement challenge. A Fourier domain normalization approach is used in the Fourier optical imaging code to simulate the full three-dimensional scattered light field of nominally 15 nm sized structures, accurately replicating the light field as a function of the focus position. Using the full three-dimensional light field, nanometer scale details such as a 2 nm thin conformal oxide and nanometer topography are rigorously fitted for features less than 1/30(th) of the wavelength in size. The densely packed structures are positioned nearly an order of magnitude closer than the conventional Rayleigh resolution limit and can be measured with sub-nanometer parametric uncertainties. This approach enables a practical measurement sensitivity to size variations of only a few atoms in size using a high throughput optical configuration with broad application in measuring nanometric structures and nanoelectronic devices.

  8. Three-dimensional deep sub-diffraction optical beam lithography with 9 nm feature size.

    PubMed

    Gan, Zongsong; Cao, Yaoyu; Evans, Richard A; Gu, Min

    2013-01-01

    The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometre range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometre feature and resolution in optical beam lithography. Here we report on three-dimensional optical beam lithography with 9 nm feature size and 52 nm two-line resolution in a newly developed two-photon absorption resin with high mechanical strength. The revealed dependence of the feature size and the two-line resolution confirms that they can reach deep sub-diffraction scale but are limited by the mechanical strength of the new resin. Our result has paved the way towards portable three-dimensional maskless laser direct writing with resolution fully comparable to electron beam lithography.

  9. Pointing, acquisition, and tracking architecture tools for deep-space optical communications

    NASA Astrophysics Data System (ADS)

    Mohan, Swati; Alvarez-Salazar, Oscar; Birnbaum, Kevin; Biswas, Abhijit; Farr, William; Hemmati, Hamid; Johnson, Shawn; Ortiz, Geraldo; Quirk, Kevin; Rahman, Zahidul; Regher, Martin; Rizvi, Farheen; Shields, Joel; Srinivasan, Meera

    2014-03-01

    Deep-Space Optical Communications is a key emerging technology that is being pursued for high data-rate communications, which may enable rates up to ten times more than current Ka-band technology. Increasing the frequency of communication, from Ka-band to optical, allows for a higher data rate transfers. However, as the frequency of communication increases, the beam divergence decreases. Less beam divergence requires more accurate and precise pointing to make contact with the receiver. This would require a three-order-of-magnitude improvement from Ka-Band (~ 1 mrad) to optical (~ 1 urad) in the required pointing. Finding an architecture that can provide the necessary pointing capability is driven by many factors, such as allocated signal loss due to pointing, range to Earth, spacecraft disturbance profile, spacecraft base pointing capability, isolation scheme, and detector characteristics. We have developed a suite of tools to 1) flow down a set of pointing requirements (Error Budget Tool), 2) determine a set of architectures capable of meeting the requirements (Pointing Architecture Tool), and 3) assess the performance of possible architecture over the mission trajectory (Systems Engineering Tool). This paper describes the three tools and details their use through the case study of the Asteroid Retrieval Mission. Finally, this paper details which aspects of the pointing, acquisition, and tracking subsystem still require technology infusion, and the future steps needed to implement these pointing architectures.

  10. Reflected Sunlight Reduction and Characterization for a Deep-Space Optical Receiver Antenna (DSORA)

    NASA Technical Reports Server (NTRS)

    Clymer, B. D.

    1990-01-01

    A baffle system for the elimination of first-order specular and diffuse reflection of sunlight from the sunshade of a deep-space optical receiver telescope is presented. This baffle system consists of rings of 0.5cm blades spaced 2.5 cm apart on the walls of GO hexagonal sunshade tubes that combine to form the telescope sunshade. The shadow cast by the blades, walls, and rims of the tubes prevent all first-order reflections of direct sunlight from reaching the primary mirror of the telescope. A reflection model of the sunshade without baffles is also presented for comparison. Since manufacturers of absorbing surfaces do not measure data near grazing incidence, the reflection properties at anticipated angles of incidence must be characterized. A description of reflection from matte surfaces in term of bidirectional reflection distribution function (BRDF) is presented along with a discussion of measuring BRDF near grazing incidence.

  11. Needle optical coherence elastography for the measurement of microscale mechanical contrast deep within human breast tissues

    NASA Astrophysics Data System (ADS)

    Kennedy, Kelsey M.; McLaughlin, Robert A.; Kennedy, Brendan F.; Tien, Alan; Latham, Bruce; Saunders, Christobel M.; Sampson, David D.

    2013-12-01

    Optical coherence elastography (OCE) is an emerging imaging technique that probes microscale mechanical contrast in tissues with the potential to differentiate healthy and malignant tissues. However, conventional OCE techniques are limited to imaging the first 1 to 2 mm of tissue in depth. We demonstrate, for the first time, OCE measurements deep within human tissues using needle OCE, extending the potential of OCE as a surgical guidance tool. We use needle OCE to detect tissue interfaces based on mechanical contrast in both normal and malignant breast tissues in freshly excised human mastectomy samples, as validated against histopathology. Further, we demonstrate the feasibility of in situ measurements >4 cm from the tissue surface using ultrasound guidance of the OCE needle probe. With further refinement, our method may potentially aid in accurate detection of the boundary of the tumor to help ensure full removal of all malignant tissues, which is critical to the success of breast-conserving surgery.

  12. RbMgCO₃F: A New Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material.

    PubMed

    Tran, T Thao; He, Jiangang; Rondinelli, James M; Halasyamani, P Shiv

    2015-08-26

    A new deep-ultraviolet nonlinear optical material, RbMgCO3F, has been synthesized and characterized. The achiral nonpolar acentric material is second harmonic generation (SHG) active at both 1064 and 532 nm, with efficiencies of 160 × α-SiO2 and 0.6 × β-BaB2O4, respectively, and exhibits a short UV cutoff, below 190 nm. RbMgCO3F possesses a three-dimensional structure of corner-shared Mg(CO3)2F2 polyhedra. Unlike other acentric carbonate fluorides, in this example, the inclusion of Mg(2+) creates pentagonal channels where the Rb(+) resides. Our electronic structure calculations reveal that the denticity of the carbonate linkage, monodentate or bidendate, to the divalent cation is a useful parameter for tuning the transparency window and achieving the sizable SHG response.

  13. Fully reflective deep ultraviolet to near infrared spectrometer and entrance optics for resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Schulz, B.; Bäckström, J.; Budelmann, D.; Maeser, R.; Rübhausen, M.; Klein, M. V.; Schoeffel, E.; Mihill, A.; Yoon, S.

    2005-07-01

    We present the design and performance of a new triple-grating deep ultraviolet to near-infrared spectrometer. The system is fully achromatic due to the use of reflective optics. The minimization of image aberrations by using on- and off- axis parabolic mirrors as well as elliptical mirrors yields a strong stray light rejection with high resolution over a wavelength range between 165 and 1000nm. The Raman signal is collected with a reflective entrance objective with a numerical aperture of 0.5, featuring a Cassegrain-type design. Resonance Raman studies on semiconductors and on correlated compounds, such as LaMnO3, highlight the performance of this instrument, and show diverse resonance effects between 1.96 and 5.4eV.

  14. Deep-Ultraviolet Nonlinear Optics in a Borate Framework with 21-Ring Channels.

    PubMed

    Wei, Qi; Wang, Jia-Jia; He, Chao; Cheng, Jian-Wen; Yang, Guo-Yu

    2016-07-25

    A new borate LiBa3 (OH)[B9 O16 ][B(OH)4 ], which combines the uniform porosity of open-frameworks with the extraordinary NLO properties of borates, has been obtained under hydrothermal conditions by using mixed lithium and barium ions as templates. The framework displays an acs-type net with large 21-ring channels. The second harmonic generation (SHG) measurement shows that it is a type I phase-matchable material with a strong SHG signal intensity about 3.1 times that of KDP (KH2 PO4 ). UV/Vis-NIR diffuse reflectance analysis indicates that the compound has a wide transparency range with the short-wavelength absorption edge below 200 nm. These characteristics reveal that the compound is a promising deep-UV nonlinear optical material.

  15. The Ground-based Electro-Optical Deep Space Surveillance /GEODSS/ system

    NASA Astrophysics Data System (ADS)

    Jeas, W. C.; Anctil, R.

    1981-11-01

    After an account of the four-site Baker-Nunn telescope system that was its forerunner, the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) system is described with attention to its function, capabilities, and such system elements as its telescopes and their mounts, TV camera, automatic moving target indicator (AMTI), and software. GEODSS is a passive tracking system operating within the constraints of night skies and atmospheric conditions, and consists of two 40-inch aperture wide-field telescopes equipped with sensitive, low light level television cameras and radiometers that are coupled to signal processors and computerized system management. Satellite signal detection is by means of the sunlight reflected by objects as dim as 16.0 m and site locations are in New Mexico, South Korea, Diego Garcia and the Eastern Atlantic, providing overlapping sky coverage. Detection, observation and object orbit element maintenance extends to altitudes of 40,000 km.

  16. The Chandra Deep Field South as a test case for Global Multi Conjugate Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Portaluri, E.; Viotto, V.; Ragazzoni, R.; Gullieuszik, M.; Bergomi, M.; Greggio, D.; Biondi, F.; Dima, M.; Magrin, D.; Farinato, J.

    2017-04-01

    The era of the next generation of giant telescopes requires not only the advent of new technologies but also the development of novel methods, in order to exploit fully the extraordinary potential they are built for. Global Multi Conjugate Adaptive Optics (GMCAO) pursues this approach, with the goal of achieving good performance over a field of view of a few arcmin and an increase in sky coverage. In this article, we show the gain offered by this technique to an astrophysical application, such as the photometric survey strategy applied to the Chandra Deep Field South as a case study. We simulated a close-to-real observation of a 500 × 500 arcsec2 extragalactic deep field with a 40-m class telescope that implements GMCAO. We analysed mock K-band images of 6000 high-redshift (up to z = 2.75) galaxies therein as if they were real to recover the initial input parameters. We attained 94.5 per cent completeness for source detection with SEXTRACTOR. We also measured the morphological parameters of all the sources with the two-dimensional fitting tools GALFIT. The agreement we found between recovered and intrinsic parameters demonstrates GMCAO as a reliable approach to assist extremely large telescope (ELT) observations of extragalactic interest.

  17. New i-line and deep-UV optical wafer stepper

    NASA Astrophysics Data System (ADS)

    Unger, Robert; Disessa, Peter A.

    1991-07-01

    A new line of optical wafer steppers is discussed. These tools, which have been developed in conjunction with Sematech and its member companies, feature new high-numerical aperture, widefield reduction lenses for operation at either i-line (365 nm) or deep-UV (248 nm) wavelengths. The i-line tool achieves practical resolution at the 0.50 micrometers level with usable working focal depth, while the deep-UV tool is capable of practical resolution at the 0.35 micrometers level with usable working focal depth. The design of these tools incorporates and expands upon optical wafer stepper technologies which have been field proven, particularly in the areas of alignment, focusing, INSITUTM metrology, automatic calibration, and diagnostic utilities. New features added to theses tools, to support their application at or below 0.50 micrometers , include a new system structure designed for inherent stability to maintain tight coupling among the imaging and alignment subsystems, and wafer stage advancements to achieve increased positioning accuracy, which supports obtaining overall tool overlay accuracy commensurate with sub-half-micron resolution. Of particular significance is the incorporation of a field-by-field leveling system, which optimizes the usable depth of focus over large image fields on product wafers. The tools also include an entirely new control system, which has been designed based on a new hierarchical control architecture, and incorporates digital servo controls and automated diagnostics. The control interface is designed as an intuitive graphic touch screen display, providing simplicity to the operator and significant job process flexibility, compatible with advanced memory and Application Specific Integrated Circuits (ASIC) fab operations. Design considerations for these tools are described together with performance results obtained in the field.

  18. V photometry of Titania, Oberon, and Triton

    SciTech Connect

    Goguen, J.D.; Hammel, H.B.; Brown, R.H.

    1989-02-01

    The phase angle and orbital brightness variations of Titania, Oberon, and Triton are presently obtained through analysis of V filter photometry obtained at Mauna Kea in 1982-1983. While Titania and Oberon exhibit magnitude variations with phase angle comparable to those of low-to-moderate albedo asteroids observed within several deg of opposition, Triton's phase variation is distinctly different from these and has a phase coefficient consistent with either a high-albedo regolith or an optically thick nonparticulate scattering layer (perhaps an atmosphere, or an ocean). A low-albedo regolith cannot on the strength of these data be ruled out, however. 39 references.

  19. V photometry of Titania, Oberon, and Triton

    NASA Astrophysics Data System (ADS)

    Goguen, J. D.; Hammel, H. B.; Brown, R. H.

    1989-02-01

    The phase angle and orbital brightness variations of Titania, Oberon, and Triton are presently obtained through analysis of V filter photometry obtained at Mauna Kea in 1982-1983. While Titania and Oberon exhibit magnitude variations with phase angle comparable to those of low-to-moderate albedo asteroids observed within several deg of opposition, Triton's phase variation is distinctly different from these and has a phase coefficient consistent with either a high-albedo regolith or an optically thick nonparticulate scattering layer (perhaps an atmosphere, or an ocean). A low-albedo regolith cannot on the strength of these data be ruled out, however.

  20. V photometry of Titania, Oberon, and Triton

    NASA Technical Reports Server (NTRS)

    Goguen, J. D.; Hammel, H. B.; Brown, R. H.

    1989-01-01

    The phase angle and orbital brightness variations of Titania, Oberon, and Triton are presently obtained through analysis of V filter photometry obtained at Mauna Kea in 1982-1983. While Titania and Oberon exhibit magnitude variations with phase angle comparable to those of low-to-moderate albedo asteroids observed within several deg of opposition, Triton's phase variation is distinctly different from these and has a phase coefficient consistent with either a high-albedo regolith or an optically thick nonparticulate scattering layer (perhaps an atmosphere, or an ocean). A low-albedo regolith cannot on the strength of these data be ruled out, however.

  1. k2photometry: Read, reduce and detrend K2 photometry

    NASA Astrophysics Data System (ADS)

    Van Eylen, Vincent; Nowak, Grzegorz; Albrecht, Simon; Palle, Enric; Ribas, Ignasi; Bruntt, Hans; Perger, Manuel; Gandolfi, Davide; Hirano, Teriyuki; Sanchis-Ojeda, Roberto; Kiilerich, Amanda; Arranz, Jorge P.; Badenas, Mariona; Dai, Fei; Deeg, Hans J.; Guenther, Eike W.; Montanes-Rodriguez, Pilar; Narita, Norio; Rogers, Leslie A.; Bejar, Victor J. S.; Shrotriya, Tushar S.; Winn, Joshua N.; Sebastian, Daniel

    2016-02-01

    k2photometry reads, reduces and detrends K2 photometry and searches for transiting planets. MAST database pixel files are used as input; the output includes raw lightcurves, detrended lightcurves and a transit search can be performed as well. Stellar variability is not typically well-preserved but parameters can be tweaked to change that. The BLS algorithm used to detect periodic events is a Python implementation by Ruth Angus and Dan Foreman-Mackey (https://github.com/dfm/python-bls).

  2. Atmospheric aerosol optical parameters, deep convective clouds and hail occurence - a correlation study

    NASA Astrophysics Data System (ADS)

    Talianu, Camelia; Andrei, Simona; Toanca, Florica; Stefan, Sabina

    2016-04-01

    Among the severe weather phenomena, whose frequency has increased during the past two decades, hail represents a major threat not only for agriculture but also for other economical fields. Generally, hail are produced in deep convective clouds, developed in an unstable environment. Recent studies have emphasized that besides the state of the atmosphere, the atmospheric composition is also very important. The presence of fine aerosols in atmosphere could have a high impact on nucleation processes, initiating the occurrence of cloud droplets, ice crystals and possibly the occurrence of graupel and/or hail. The presence of aerosols in the atmosphere, correlated with specific atmospheric conditions, could be predictors of the occurrence of hail events. The atmospheric investigation using multiwavelength Lidar systems can offer relevant information regarding the presence of aerosols, identified using their optical properties, and can distinguish between spherical and non-spherical shape, and liquid and solid phase of these aerosols. The aim of this study is to analyse the correlations between the presence and the properties of aerosols in atmosphere, and the production of hail events in a convective environment, using extensive and intensive optical parameters computed from lidar and ceilometer aerosols measurements. From these correlations, we try to evaluate if these aerosols can be taken into consideration as predictors for hail formation. The study has been carried out in Magurele - Romania (44.35N, 26.03E, 93m ASL) using two collocated remote sensing systems: a Raman Lidar (RALI) placed at the Romanian Atmospheric 3D Observatory and a ceilometer CL31 placed at the nearby Faculty of Physics, University of Bucharest. To evaluate the atmospheric conditions, radio sounding and satellite images were used. The period analysed was May 1st - July 15th, 2015, as the May - July period is climatologically favorable for deep convection events. Two hail events have been

  3. 40-Gbps optical backbone network deep packet inspection based on FPGA

    NASA Astrophysics Data System (ADS)

    Zuo, Yuan; Huang, Zhiping; Su, Shaojing

    2014-11-01

    In the era of information, the big data, which contains huge information, brings about some problems, such as high speed transmission, storage and real-time analysis and process. As the important media for data transmission, the Internet is the significant part for big data processing research. With the large-scale usage of the Internet, the data streaming of network is increasing rapidly. The speed level in the main fiber optic communication of the present has reached 40Gbps, even 100Gbps, therefore data on the optical backbone network shows some features of massive data. Generally, data services are provided via IP packets on the optical backbone network, which is constituted with SDH (Synchronous Digital Hierarchy). Hence this method that IP packets are directly mapped into SDH payload is named POS (Packet over SDH) technology. Aiming at the problems of real time process of high speed massive data, this paper designs a process system platform based on ATCA for 40Gbps POS signal data stream recognition and packet content capture, which employs the FPGA as the CPU. This platform offers pre-processing of clustering algorithms, service traffic identification and data mining for the following big data storage and analysis with high efficiency. Also, the operational procedure is proposed in this paper. Four channels of 10Gbps POS signal decomposed by the analysis module, which chooses FPGA as the kernel, are inputted to the flow classification module and the pattern matching component based on TCAM. Based on the properties of the length of payload and net flows, buffer management is added to the platform to keep the key flow information. According to data stream analysis, DPI (deep packet inspection) and flow balance distribute, the signal is transmitted to the backend machine through the giga Ethernet ports on back board. Practice shows that the proposed platform is superior to the traditional applications based on ASIC and NP.

  4. UBV photometry of Cyg X-1 from 1996 to 2003

    NASA Astrophysics Data System (ADS)

    Voloshina, I. B.; Lyuty, V.

    2004-07-01

    The preliminary results of analysis of $UBV$-photometry of the black hole candidate Cyg X-1 in primary minimum are presented. These observations were carried out with the main goal of studying in detail the variability that was detected by Lyuty in 1985 in the optical light curve of this system near orbital phase 0.00.

  5. Radio timing and optical photometry of the black widow system PSR J1518+0204C in the globular cluster M5

    SciTech Connect

    Pallanca, C.; Ferraro, F. R.; Dalessandro, E.; Lanzoni, B.; Hessels, J. W. T.; Stairs, I.; Freire, P. C. C.

    2014-11-01

    We report on the determination of astrometric, spin, and orbital parameters for PSR J1518+0204C, a 'black widow' binary millisecond pulsar in the globular cluster (GC) M5. The accurate position and orbital parameters obtained from radio timing allowed us to search for the optical companion. By using WFC3/Hubble Space Telescope images, we identified a very faint variable star (m{sub F390W} ≳ 24.8, m{sub F606W} ≳ 24.3, m{sub F814W} ≳ 23.1) located at only 0.''25 from the pulsar's timing position. Due to its strong variability, this star is visible only in a subsample of images. However, the light curve obtained folding the available data with the orbital parameters of the pulsar shows a maximum at the pulsar inferior conjunction and a possible minimum at the pulsar superior conjunction. Furthermore, the shape of the optical modulation indicates a heating process possibly due to the pulsar wind. This is the first identification of an optical companion to a black widow pulsar in the dense stellar environment of a GC.

  6. How the extinction of extragalactic background light affects surface photometry of galaxies, groups and clusters

    NASA Astrophysics Data System (ADS)

    Zackrisson, E.; Micheva, G.; Östlin, G.

    2009-08-01

    The faint regions of galaxies, groups and clusters hold important clues about how these objects formed, and surface photometry at optical and near-infrared wavelengths represents a powerful tool for studying such structures. Here, we identify a hitherto unrecognized problem with this technique, related to how the night sky flux is typically measured and subtracted from astronomical images. While most of the sky flux comes from regions between the observer and the target object, a small fraction - the extragalactic background light (EBL) - comes from behind. We argue that since this part of the sky flux can be subjected to extinction by dust present in the galaxy/group/cluster studied, standard reduction procedures may lead to a systematic oversubtraction of the EBL. Even very small amounts of extinction can lead to spurious features in radial surface brightness profiles and colour maps of extended objects. We assess the likely impact of this effect on a number of topics in extragalactic astronomy where very deep surface photometry is currently attempted, including studies of stellar haloes, starburst host galaxies, disc truncations and diffuse intragroup/intracluster light. We argue that EBL extinction may provide at least a partial explanation for the anomalously red colours reported for the haloes of disc galaxies and for the hosts of local starburst galaxies. EBL extinction effects also mimic truncations in discs with unusually high dust opacities, but are unlikely to be the cause of such features in general. Failure to account for EBL extinction can also give rise to a non-negligible underestimate of intragroup and intracluster light at the faintest surface brightness levels currently probed. Finally, we discuss how EBL extinction effects may be exploited to provide an independent constraint on the surface brightness of the EBL, using a combination of surface photometry and direct star counts.

  7. Visible to deep ultraviolet range optical absorption of electron irradiated borosilicate glass

    NASA Astrophysics Data System (ADS)

    Wang, Tie-Shan; Duan, Bing-Huang; Tian, Feng; Peng, Hai-Bo; Chen, Liang; Zhang, Li-Min; Yuan, Wei

    2015-07-01

    To study the room-temperature stable defects induced by electron irradiation, commercial borosilicate glasses were irradiated by 1.2 MeV electrons and then ultraviolet (UV) optical absorption (OA) spectra were measured. Two characteristic bands were revealed before irradiation, and they were attributed to silicon dangling bond (E’-center) and Fe3+ species, respectively. The existence of Fe3+ was confirmed by electron paramagnetic resonance (EPR) measurements. After irradiation, the absorption spectra revealed irradiation-induced changes, while the content of E’-center did not change in the deep ultraviolet (DUV) region. The slightly reduced OA spectra at 4.9 eV was supposed to transform Fe3+ species to Fe2+ species and this transformation leads to the appearance of 4.3 eV OA band. By calculating intensity variation, the transformation of Fe was estimated to be about 5% and the optical absorption cross section of Fe2+ species is calculated to be 2.2 times larger than that of Fe3+ species. Peroxy linkage (POL, ≡Si-O-O-Si≡), which results in a 3.7 eV OA band, is speculated not to be from Si-O bond break but from Si-O-B bond, Si-O-Al bond, or Si-O-Na bond break. The co-presence defect with POL is probably responsible for 2.9-eV OA band. Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. lzujbky-2014-16).

  8. Division B Commission 25: Astronomical Photometry and Polarimetry

    NASA Astrophysics Data System (ADS)

    Walker, Alistair; Adelman, Saul; Milone, Eugene; Anthony-Twarog, Barbara; Bastien, Pierre; Chen, Wen Ping; Howell, Steve; Knude, Jens; Kurtz, Donald; Magalhães, Antonio Mario; Menzies, John; Smith, Allyn; Volk, Kevin

    2016-04-01

    Commission 25 (C25) deals with the techniques and issues involved with the measurement of optical and infrared radiation intensities and polarization from astronomical sources. As such, in recent years attention has focused on photometric standard stars, atmospheric extinction, photometric passbands, transformation between systems, nomenclature, and observing and reduction techniques. At the start of the trimester C25 changed its name from Stellar Photometry and Polarization to Astronomical Photometry and Polarization so as to explicitly include in its mandate particular issues arising from the measurement of resolved sources, given the importance of photometric redshifts of distant galaxies for many of the large photometric surveys now underway. We begin by summarizing commission activities over the 2012-2014 period, follow with a report on Polarimetry, continue with Photometry topics that have been of interest to C25 members, and conclude with a Vision for the Future.

  9. Photometry Of The Semi-regular Variable Tx Tau

    NASA Astrophysics Data System (ADS)

    Wyman, Katherine; Spear, G.; McLin, K.; Cominsky, L.; Mankiewicz, L.; Reichart, D.; Ivarsen, K.

    2009-12-01

    We report V-band and I-band photometry for the SRA type variable TX Tau. Photometry was obtained using the robotic telescope GORT at the Hume Observatory (NASA funded through Sonoma State University) and the PROMPT robotic telescopes at Cerro Tololo Inter-American Observatory (NSF and NASA funded through the University of North Carolina). Photometry was also obtained using the PI of the Sky optical transient search system at Las Campanas Observatory developed by a consortium of institutions in Poland. Modern periods are determined, the V-band and I-band light curves are compared, and V-I colors are derived. It is possible that the classification for this variable should be reconsidered.

  10. Deep learning as a tool to distinguish between high orbital angular momentum optical modes

    NASA Astrophysics Data System (ADS)

    Knutson, E. M.; Lohani, Sanjaya; Danaci, Onur; Huver, Sean D.; Glasser, Ryan T.

    2016-09-01

    The generation of light containing large degrees of orbital angular momentum (OAM) has recently been demon- strated in both the classical and quantum regimes. Since there is no fundamental limit to how many quanta of OAM a single photon can carry, optical states with an arbitrarily high difference in this quantum number may, in principle, be entangled. This opens the door to investigations into high-dimensional entanglement shared between states in superpositions of nonzero OAM. Additionally, making use of non-zero OAM states can allow for a dramatic increase in the amount of information carried by a single photon, thus increasing the information capacity of a communication channel. In practice, however, it is difficult to differentiate between states with high OAM numbers with high precision. Here we investigate the ability of deep neural networks to differentiate between states that contain large values of OAM. We show that such networks may be used to differentiate be- tween nearby OAM states that contain realistic amounts of noise, with OAM values of up to 100. Additionally, we examine how the classification accuracy scales with the signal-to-noise ratio of images that are used to train the network, as well as those being tested. Finally, we demonstrate the simultaneous classification of < 100 OAM states with greater than 70 % accuracy. We intend to verify our system with experimentally-produced classi- cal OAM states, as well as investigate possibilities that would allow this technique to work in the few-photon quantum regime.

  11. Fluorooxoborates: Beryllium-Free Deep-Ultraviolet Nonlinear Optical Materials without Layered Growth.

    PubMed

    Zhang, Bingbing; Shi, Guoqiang; Yang, Zhihua; Zhang, Fangfang; Pan, Shilie

    2017-03-02

    Deep-ultraviolet nonlinear optical (DUV NLO) crystals are the key materials to extend the output range of solid-state lasers to below 200 nm. The only practical material KBe2 BO3 F2 suffers high toxicity through beryllium and strong layered growth. Herein, we propose a beryllium-free material design and synthesis strategy for DUV NLO materials. Introducing the (BO3 F)(4-) , (BO2 F2 )(3-) , and (BOF3 )(2-) groups in borates could break through the fixed 3D B-O network that would produce a larger birefringence without layering and simultaneously keep a short cutoff edge down to DUV. The theoretical and experimental studies on a series of fluorooxoborates confirm this strategy. Li2 B6 O9 F2 is identified as a DUV NLO material with a large second harmonic generation efficiency (0.9×KDP) and a large predicted birefringence (0.07) without layering. This study provides a feasible way to break down the DUV wall for NLO materials.

  12. Optimizations of a Hardware Decoder for Deep-Space Optical Communications

    NASA Technical Reports Server (NTRS)

    Cheng, Michael K.; Nakashima, Michael A.; Moision, Bruce E.; Hamkins, Jon

    2007-01-01

    The National Aeronautics and Space Administration has developed a capacity approaching modulation and coding scheme that comprises a serial concatenation of an inner accumulate pulse-position modulation (PPM) and an outer convolutional code [or serially concatenated PPM (SCPPM)] for deep-space optical communications. Decoding of this code uses the turbo principle. However, due to the nonbinary property of SCPPM, a straightforward application of classical turbo decoding is very inefficient. Here, we present various optimizations applicable in hardware implementation of the SCPPM decoder. More specifically, we feature a Super Gamma computation to efficiently handle parallel trellis edges, a pipeline-friendly 'maxstar top-2' circuit that reduces the max-only approximation penalty, a low-latency cyclic redundancy check circuit for window-based decoders, and a high-speed algorithmic polynomial interleaver that leads to memory savings. Using the featured optimizations, we implement a 6.72 megabits-per-second (Mbps) SCPPM decoder on a single field-programmable gate array (FPGA). Compared to the current data rate of 256 kilobits per second from Mars, the SCPPM coded scheme represents a throughput increase of more than twenty-six fold. Extension to a 50-Mbps decoder on a board with multiple FPGAs follows naturally. We show through hardware simulations that the SCPPM coded system can operate within 1 dB of the Shannon capacity at nominal operating conditions.

  13. Correlations between optical/near-infrared and UV extinction parameters and the prediction of UV extinction from ground-based photometry

    NASA Technical Reports Server (NTRS)

    Cardelli, Jason A.; Clayton, Goeffrey C.; Mathis, John S.

    1988-01-01

    An analysis of the variability of absolute UV extinction, A lambda derived through the ratio total-to-selective extinction, R Av/E(B-V), for 31 lines of sight for which UV extinction parameters were derived, is presented. For these data, which sample a wide range of environments and which are characterized by R = 2.5 to 6.0, differences in the shapes of UV extinction curves are largely due to variations in optical/near-UV extinction through changes in R. From this, it is found that UV extinction curves can be reproduced with reasonable accuracy by simply knowing R. Detection of an A2175/E(B-V) = 10 + or - 1 mag implies that the total extinction at 2175 A can be estimated from E(B-V) alone.

  14. Probability of the Physical Association of 104 Blended Companions to Kepler Objects of Interest Using Visible and Near-infrared Adaptive Optics Photometry

    NASA Astrophysics Data System (ADS)

    Atkinson, Dani; Baranec, Christoph; Ziegler, Carl; Law, Nicholas; Riddle, Reed; Morton, Tim

    2017-01-01

    We determine probabilities of physical association for stars in blended Kepler Objects of Interest (KOIs), and find that 14.5{ % }-3.4 % +3.8 % of companions within ∼4″ are consistent with being physically unassociated with their primary. This produces a better understanding of potential false positives in the Kepler catalog and will guide models of planet formation in binary systems. Physical association is determined through two methods of calculating multi-band photometric parallax using visible and near-infrared adaptive optics observations of 84 KOI systems with 104 contaminating companions within ∼4″. We find no evidence that KOI companions with separations of less than 1″ are more likely to be physically associated than KOI companions generally. We also reinterpret transit depths for 94 planet candidates, and calculate that 2.6% ± 0.4% of transits have R> 15{R}\\oplus , which is consistent with prior modeling work.

  15. Interpreting Flux from Broadband Photometry

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.; Breeveld, Alice; Roming, Peter W. A.; Siegel, Michael

    2016-10-01

    We discuss the transformation of observed photometry into flux for the creation of spectral energy distributions (SED) and the computation of bolometric luminosities. We do this in the context of supernova studies, particularly as observed with the Swift spacecraft, but the concepts and techniques should be applicable to many other types of sources and wavelength regimes. Traditional methods of converting observed magnitudes to flux densities are not very accurate when applied to UV photometry. Common methods for extinction and the integration of pseudo-bolometric fluxes can also lead to inaccurate results. The sources of inaccuracy, though, also apply to other wavelengths. Because of the complicated nature of translating broadband photometry into monochromatic flux densities, comparison between observed photometry and a spectroscopic model is best done by forward modeling the spectrum into the count rates or magnitudes of the observations. We recommend that integrated flux measurements be made using a spectrum or SED which is consistent with the multi-band photometry rather than converting individual photometric measurements to flux densities, linearly interpolating between the points, and integrating. We also highlight some specific areas where the UV flux can be mischaracterized.

  16. Water Optical Properties and Water Color Remote Sensing in Optically Deep and Shallow Waters of Lake Taihu, China

    NASA Astrophysics Data System (ADS)

    Xi, Hongyan

    In this study, Lake Taihu in Jiangsu Province of China, a typical large freshwater lake, is selected as the study area. Based on the field spectral measurements and laboratory analyses performed in October 2008, water optical properties and water color/quality remote sensing retrieval models in Lake Taihu were investigated. It was recognized that water quality varied a lot in different areas. Waters in Lake Taihu were classified as optically deep waters (ODWs) and optically shallow waters (OSWs). ODWs are the waters where the water depth is more than three times the measured Secchi Disk Depth (SDD), otherwise they are OSWs. Cyanobacteria blooms happen frequently in ODWs and the water is eutrophicated heavily. Whereas water is very clear with rare cyanobacteria blooms but many aquatic plants in OSWs. Focused on the two types of water areas respectively, the inherent optical properties (lOPs), apparent optical properties (lOPs) and reflectance spectra were analyzed, as well as their relationships to water quality parameters. Local optical parameters f and Q, which play significant roles in water quality parameters retrieval models, were also determined. Measured remote sensing reflectance data were used to establish two-band and three-band models for chlorophyll-a (Chl-a) concentration estimation, results showed both models were suitable in ODWs. However, aquatic plants in OSWs had great influence on spectra, resulting in the inapplicability of the established models at these sites. Absorption and backscattering coefficients were used to remove those influences and simulate new set of remote sensing reflectance based on radiative transfer theory, which were proved reliable to establish Chl-a retrieval algorithms. Three-band model established by simulated spectra showed more satisfactory performance in whole ODWs, and performance of two-band model in OSWs was also enhanced much. Several models were established to estimate total suspended solids (TSS) concentrations

  17. Detection by Transit Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William J.; Koch, David G.; Jenkins, Jon M.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    A periodic sequence of planetary transits provides a valid detection of an orbiting planet and provides the relative size of the planet and its orbital period. Ancillary measurements of the stellar spectrum and the variations of the star's radial velocity or position combined with stellar models allow the absolute size of the planet and its mass to be obtained. The results of this approach have already shown that the planet orbiting HD209458 has only 70% of the mass of Jupiter, but is nearly 50% larger in radius. Based on models of planetary structure, these results imply that the planet must have spent most of its lifetime so close to the star that it has not been able to cool and contract as have the giant planets in our Solar System. Thus its density is much less than Jupiter and Saturn and is actually less than that of water; i.e., about 0.4 gr/cu cm. If more sensitive measurements of the light curve of stars with closely orbiting planets can be made that provide the varying amplitude of the light reflected by the planet at various phases in its orbit, then characteristics of the planetary atmosphere can be obtained. Potentially, these data can identify major molecular species present in the atmosphere and tell us if clouds are present and yield the phase function of the aerosols. Although such detail cannot be obtained for Earth-size planets because their signal amplitudes are too small, it is possible to get data critical to the determination of the structure of extrasolar planetary systems. In particular, the size distributions and their orbital distributions can be measured by the transit photometry missions now in development. The COROT mission should be able to find large terrestrial planets in short-period orbits while the more ambitious Kepler and Eddington missions should be able to detect planets even smaller than the Earth and at orbital distances that place them in the habitable zone of their stars.

  18. Sub-mm Scale Fiber Guided Deep/Vacuum Ultra-Violet Optical Source for Trapped Mercury Ion Clocks

    NASA Technical Reports Server (NTRS)

    Yi, Lin; Burt, Eric A.; Huang, Shouhua; Tjoelker, Robert L.

    2013-01-01

    We demonstrate the functionality of a mercury capillary lamp with a diameter in the sub-mm range and deep ultraviolet (DUV)/ vacuum ultraviolet (VUV) radiation delivery via an optical fiber integrated with the capillary. DUV spectrum control is observed by varying the fabrication parameters such as buffer gas type and pressure, capillary diameter, electrical resonator design, and temperature. We also show spectroscopic data of the 199Hg+ hyper-fine transition at 40.5GHz when applying the above fiber optical design. We present efforts toward micro-plasma generation in hollow-core photonic crystal fiber with related optical design and theoretical estimations. This new approach towards a more practical DUV optical interface could benefit trapped ion clock developments for future ultra-stable frequency reference and time-keeping applications.

  19. Radio-optical reference frame link using the U.S. Naval observatory astrograph and deep CCD imaging

    SciTech Connect

    Zacharias, N.; Zacharias, M. I.

    2014-05-01

    Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reduced following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3σ level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.

  20. Strong [Fe X] Emission and Deep Optical Eclipses of the Classical Nova V5593 Sgr 2012 No. 5

    NASA Astrophysics Data System (ADS)

    Starrfield, Sumner; Wagner, R. Mark; Walter, Frederick M.; Woodward, Charles E.; Schwarz, Greg; Krautter, Joachim

    2016-01-01

    V5593 Sgr was discovered by T. Kojima on 2012 July 16.512 UT at a magnitude of ~12.6. A low-resolution spectrum obtained by M. Fujii on 2012 July 18.572 UT confirmed that the object was indeed a Classical Nova. The AAVSO V-band light curve showed that the nova peaked near 11th mag on July 23-24 UT and subsequently declined in brightness with a t_2 of about 27 days making it a moderately fast nova. We obtained optical spectroscopy of V5593 Sgr between 2012 July 26 and 2013 February 19 UT with the SMARTS/CTIO 1.5 m telescope (+RC spectrograph) and then between 2014 August 25 and 2015 June 17 UT using the MDM Observatory 2.4 m Hiltner telescope (+CCDS), the 8.4 m Large Binocular Telescope (+MODS1), and the 6.5 m MMT (+BlueChannel). The SMARTS spectra confirmed the Fe II classification but showed that by 2013 February 19 UT the Fe II lines became much weaker and strong He II 468.5 nm and [Fe VII] 608.7 nm became prominent. A spectrum obtained on 2014 August 25 UT exhibited Balmer, He II, and [Fe VII] emission lines, but also for the first time, the presence of strong [Fe X] 637.4 nm emission with an observed intensity ratio with respect to Halpha of about 1.5. Other identified emission lines in our spectra included O VI, [Ca V], [Ca VI], [Ca VII], [Fe VI], [Fe XI], and [Fe XIV]. Surprisingly, [O III] emission was weak or absent. By 2015 June, a spectrum showed that the observed [Fe X]/Halpha intensity ratio had decreased to about 0.74. Contemporaneous optical photometry was obtained with the SMARTS/CTIO 1 m telescope (+ANDICAM) between 2014 March 19 and 2015 September 28 UT in the BVRIJHK bands. In agreement with our spectra in quiescence, V5593 Sgr is very red with (B-V) ~ 1 mag and (V-K) ~ 5 mag. The photometry shows ellipsoidal-like modulations with a peak-to-peak amplitude exceeding 2 mag in R and I. The modulation is seen in B through K; however, the amplitude is lower in JHK. Brief eclipses occur at the minimum of the ellipsoidal variation with a depth of at

  1. Beryllium-free Li4Sr(BO3)2 for deep-ultraviolet nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Zhao, Sangen; Gong, Pifu; Bai, Lei; Xu, Xiang; Zhang, Shuquan; Sun, Zhihua; Lin, Zheshuai; Hong, Maochun; Chen, Chuangtian; Luo, Junhua

    2014-05-01

    Nonlinear optical (NLO) materials are of great importance in laser science and technology, as they can expand the wavelength range provided by common laser sources. Few NLO materials, except KBe2BO3F2 (KBBF), can practically generate deep-ultraviolet coherent light by direct second-harmonic generation process, limited by the fundamental requirements on the structure-directing optical properties. However, KBBF suffers a strong layering tendency and high toxicity of the containing beryllium, which hinder the commercial availability of KBBF. Here we report a new beryllium-free borate, Li4Sr(BO3)2, which preserves the structural merits of KBBF, resulting in the desirable optical properties. Furthermore, Li4Sr(BO3)2 mitigates the layering tendency greatly and enhances the efficiency of second-harmonic generation by more than half that of KBBF. These results suggest that Li4Sr(BO3)2 is an attractive candidate for the next generation of deep-ultraviolet NLO materials. This beryllium-free borate represents a new research direction in the development of deep-ultraviolet NLO materials.

  2. Experimental Evaluation of the "Polished Panel Optical Receiver" Concept on the Deep Space Network's 34 Meter Antenna

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    2012-01-01

    The potential development of large aperture ground-based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation proposes to polish the aluminum reflector panels of 34-meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by even state-of-the-art polished aluminum panels. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. A custom designed aluminum panel has been mounted on the 34 meter research antenna at Deep-Space Station 13 (DSS-13), and a remotely controlled CCD camera with a large CCD sensor in a weather-proof container has been installed next to the subreflector, pointed directly at the custom polished panel. Using the planet Jupiter as the optical point-source, the point-spread function (PSF) generated by the polished panel has been characterized, the array data processed to determine the center of the intensity distribution, and expected communications performance of the proposed polished panel optical receiver has been evaluated.

  3. Beryllium-free Li4Sr(BO3)2 for deep-ultraviolet nonlinear optical applications.

    PubMed

    Zhao, Sangen; Gong, Pifu; Bai, Lei; Xu, Xiang; Zhang, Shuquan; Sun, Zhihua; Lin, Zheshuai; Hong, Maochun; Chen, Chuangtian; Luo, Junhua

    2014-05-29

    Nonlinear optical (NLO) materials are of great importance in laser science and technology, as they can expand the wavelength range provided by common laser sources. Few NLO materials, except KBe2BO3F2 (KBBF), can practically generate deep-ultraviolet coherent light by direct second-harmonic generation process, limited by the fundamental requirements on the structure-directing optical properties. However, KBBF suffers a strong layering tendency and high toxicity of the containing beryllium, which hinder the commercial availability of KBBF. Here we report a new beryllium-free borate, Li4Sr(BO3)2, which preserves the structural merits of KBBF, resulting in the desirable optical properties. Furthermore, Li4Sr(BO3)2 mitigates the layering tendency greatly and enhances the efficiency of second-harmonic generation by more than half that of KBBF. These results suggest that Li4Sr(BO3)2 is an attractive candidate for the next generation of deep-ultraviolet NLO materials. This beryllium-free borate represents a new research direction in the development of deep-ultraviolet NLO materials.

  4. VizieR Online Data Catalog: Photometry and redshifts of galaxies in the UDF (Rafelski+, 2015)

    NASA Astrophysics Data System (ADS)

    Rafelski, M.; Teplitz, H. I.; Gardner, J. P.; Coe, D.; Bond, N. A.; Koekemoer, A. M.; Grogin, N.; Kurczynski, P.; McGrath, E. J.; Bourque, M.; Atek, H.; Brown, T. M.; Colbert, J. W.; Codoreanu, A.; Ferguson, H. C.; Finkelstein, S. L.; Gawiser, E.; Giavalisco, M.; Gronwall, C.; Hanish, D. J.; Lee, K.-S.; Mehta, V.; de Mello, D. F.; Ravindranath, S.; Ryan, R. E.; Scarlata, C.; Siana, B.; Soto, E.; Voyer, E. N.

    2016-02-01

    We present photometry and derived redshifts from up to eleven bandpasses for 9927 galaxies in the Hubble Ultra Deep field (UDF), covering an observed wavelength range from the near-ultraviolet (NUV) to the near-infrared (NIR) with Hubble Space Telescope (HST) observations. The NUV coverage of the UDF (UVUDF) is comprised of three WFC3-UVIS filters: F225W, F275W, and F336W. The UVUDF observations were obtained in 2012. The optical data are covered by the four original Advanced Camera for Surveys (ACS) optical filters: F435W, F606W, F775W, and F850LP. The deep NIR coverage includes four WFC3-IR filters: F105W, F125W, F140W, and F160W obtained in the UDF09 and UDF12 programs (Oesch et al. 2010ApJ...709L..21O, 2010ApJ...709L..16O; Bouwens et al. 2011ApJ...737...90B; Ellis et al. 2013ApJ...763L...7E; Koekemoer et al. 2013ApJS..209....3K). The entire field is also covered by three of the four WFC3-IR filters (F105W, F125W, and F160W) in the CANDELS GOODS-S observations (Grogin et al. 2011ApJS..197...35G; Koekemoer et al. 2011ApJS..197...36K). (2 data files).

  5. Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

    2015-03-01

    Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time <18 minutes. The procedure was also successful performed on a human donor eye without perforation. Our data shows the potential for iOCT-guided precision anterior segment surgery without variability as a result of tremor and improvements to standard clinical care.

  6. High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

    PubMed Central

    Chen, Wei; You, Jiang; Gu, Xiaochun; Du, Congwu; Pan, Yingtian

    2016-01-01

    Noninvasive microvascular imaging using optical coherence Doppler tomography (ODT) has shown great promise in brain studies; however, high-speed microcirculatory imaging in deep brain remains an open quest. A high-speed 1.3 μm swept-source ODT (SS-ODT) system is reported which was based on a 200 kHz vertical-cavity-surface-emitting laser. Phase errors induced by sweep-trigger desynchronization were effectively reduced by spectral phase encoding and instantaneous correlation among the A-scans. Phantom studies have revealed a significant reduction in phase noise, thus an enhancement of minimally detectable flow down to 268.2 μm/s. Further in vivo validation was performed, in which 3D cerebral-blood-flow (CBF) networks in mouse brain over a large field-of-view (FOV: 8.5 × 5 × 3.2 mm3) was scanned through thinned skull. Results showed that fast flows up to 3 cm/s in pial vessels and minute flows down to 0.3 mm/s in arterioles or venules were readily detectable at depths down to 3.2 mm. Moreover, the dynamic changes of the CBF networks elicited by acute cocaine such as heterogeneous responses in various vessel compartments and at different cortical layers as well as transient ischemic events were tracked, suggesting the potential of SS-ODT for brain functional imaging that requires high flow sensitivity and dynamic range, fast frame rate and a large FOV to cover different brain regions. PMID:27934907

  7. High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

    NASA Astrophysics Data System (ADS)

    Chen, Wei; You, Jiang; Gu, Xiaochun; Du, Congwu; Pan, Yingtian

    2016-12-01

    Noninvasive microvascular imaging using optical coherence Doppler tomography (ODT) has shown great promise in brain studies; however, high-speed microcirculatory imaging in deep brain remains an open quest. A high-speed 1.3 μm swept-source ODT (SS-ODT) system is reported which was based on a 200 kHz vertical-cavity-surface-emitting laser. Phase errors induced by sweep-trigger desynchronization were effectively reduced by spectral phase encoding and instantaneous correlation among the A-scans. Phantom studies have revealed a significant reduction in phase noise, thus an enhancement of minimally detectable flow down to 268.2 μm/s. Further in vivo validation was performed, in which 3D cerebral-blood-flow (CBF) networks in mouse brain over a large field-of-view (FOV: 8.5 × 5 × 3.2 mm3) was scanned through thinned skull. Results showed that fast flows up to 3 cm/s in pial vessels and minute flows down to 0.3 mm/s in arterioles or venules were readily detectable at depths down to 3.2 mm. Moreover, the dynamic changes of the CBF networks elicited by acute cocaine such as heterogeneous responses in various vessel compartments and at different cortical layers as well as transient ischemic events were tracked, suggesting the potential of SS-ODT for brain functional imaging that requires high flow sensitivity and dynamic range, fast frame rate and a large FOV to cover different brain regions.

  8. Post-Test Analysis of the Deep Space One Spare Flight Thruster Ion Optics

    NASA Technical Reports Server (NTRS)

    Anderson, John R.; Sengupta, Anita; Brophy, John R.

    2004-01-01

    The Deep Space 1 (DSl) spare flight thruster (FT2) was operated for 30,352 hours during the extended life test (ELT). The test was performed to validate the service life of the thruster, study known and identify unknown life limiting modes. Several of the known life limiting modes involve the ion optics system. These include loss of structural integrity for either the screen grid or accelerator grid due to sputter erosion from energetic ions striking the grid, sputter erosion enlargement of the accelerator grid apertures to the point where the accelerator grid power supply can no longer prevent electron backstreaming, unclearable shorting between the grids causes by flakes of sputtered material, and rouge hole formation due to flakes of material defocusing the ion beam. Grid gap decrease, which increases the probability of electron backstreaming and of arcing between the grids, was identified as an additional life limiting mechanism after the test. A combination of accelerator grid aperture enlargement and grid gap decrease resulted in the inability to prevent electron backstreaming at full power at 26,000 hours of the ELT. Through pits had eroded through the accelerator grid webbing and grooves had penetrated through 45% of the grid thickness in the center of the grid. The upstream surface of the screen grid eroded in a chamfered pattern around the holes in the central portion of the grid. Sputter deposited material, from the accelerator grid, adhered to the downstream surface of the screen grid and did not spall to form flakes. Although a small amount of sputter deposited material protruded into the screen grid apertures, no rouge holes were found after the ELT.

  9. Optimizations of a Turbo-Like Decoder for Deep-Space Optical Communications

    NASA Astrophysics Data System (ADS)

    Cheng, M. K.; Nakashima, M. A.; Moision, B. E.; Hamkins, J.

    2007-02-01

    The National Aeronautics and Space Administration has developed a capacity-approaching modulation and coding scheme that comprises a serial concatenation of an inner accumulate pulse-position modulation and an outer convolutional code for deep-space optical communications. Decoding of this serially concatenated pulse-position modulation (SCPPM) code uses a turbo-like algorithm. However, the inner code trellis contains many parallel edges that are not typical in standard turbo codes and, therefore, a straightforward application of classical turbo decoding is very inefficient. Here, we present various optimizations applicable in hardware implementation of the SCPPM decoder. More specifically, we feature a Super Gamma computation to efficiently handle parallel trellis edges, a "maxstar top 2" circuit fit for pipelining, a modified two's complement subtraction circuit with a shorter path delay, and a cyclic redundancy check circuit for window-based turbo decoders. We also present a polynomial interleaver where current interleaver positions can be calculated from previous positions. This recursive interleaver property enables an algorithmic realization in which no memory is needed to store the interleaver mappings. Using the featured optimizations, we implement a 6.72 megabits-per-second (Mbps) SCPPM decoder on a single field-programmable gate array (FPGA). Compared to the current data rate of 256 kbps from Mars, the SCPPM-coded scheme represents a throughput increase of more than twenty-six fold. Extension to a 50-Mbps decoder on a board with multiple FPGAs follows naturally. We show through hardware simulations that the SCPPM-coded system can operate within 1 dB of the Shannon capacity at nominal operating conditions.

  10. Tunable spin-orbit-coupled Bose-Einstein condensates in deep optical lattices

    NASA Astrophysics Data System (ADS)

    Salerno, M.; Abdullaev, F. Kh.; Gammal, A.; Tomio, Lauro

    2016-10-01

    Binary mixtures of Bose-Einstein condensates (BECs) trapped in deep optical lattices and subjected to equal contributions of Rashba and Dresselhaus spin-orbit coupling (SOC) are investigated in the presence of a periodic time modulation of the Zeeman field. SOC tunability is explicitly demonstrated by adopting a mean-field tight-binding model for the BEC mixture and by performing an averaging approach in the strong modulation limit. In this case, the system can be reduced to an unmodulated vector discrete nonlinear Schrödinger equation with a rescaled SOC tuning parameter α , which depends only on the ratio between amplitude and frequency of the applied Zeeman field. We consider the attractive interaction case and focus on the effect of the SOC tuning on the localized ground states. The dependence of the spectrum of the linear system on α has been analytically characterized. In particular, we show that extremal curves (ground and highest excited states) of the linear spectrum are continuous piecewise functions (together with their derivatives) of α , which consist of a finite number of decreasing band lobes joined by constant lines. This structure also remains in the presence of inter- and intra-species interactions, the nonlinearity mainly introducing a number of localized states in the band gaps. The stability of ground states in the presence of the modulating field has been demonstrated by real-time evolutions of the original (unaveraged) system. Localization properties of the ground state induced by the SOC tuning, and a parameter design for possible experimental observation, have also been discussed.

  11. RF and Optical Communications: A Comparison of High Data Rate Returns From Deep Space in the 2020 Timeframe

    NASA Technical Reports Server (NTRS)

    Williams, W. Dan; Collins, Michael; Boroson, Don M.; Lesh, James; Biswas, Abihijit; Orr, Richard; Schuchman, Leonard; Sands, O. Scott

    2007-01-01

    As NASA proceeds with plans for increased science data return and higher data transfer capacity for science missions, both RF and optical communications are viable candidates for significantly higher-rate communications from deep space to Earth. With the inherent advantages, smaller apertures and larger bandwidths, of optical communications, it is reasonable to expect that at some point in time and combination of increasing distance and data rate, the rapidly emerging optical capabilities would become more advantageous than the more mature and evolving RF techniques. This paper presents a comparison of the burden to a spacecraft by both RF and optical communications systems for data rates of 10, 100, and 1000 Mbps and large distances. Advanced technology for RF and optical communication systems have been considered for projecting capabilities in the 2020 timeframe. For the comparisons drawn, the optical and RF ground terminals were selected to be similar in cost. The RF system selected is composed of forty-five 12-meter antennas, whereas the selected optical system is equivalent to a 10-meter optical telescope. Potential differences in availability are disregarded since the focus of this study is on spacecraft mass and power burden for high-rate mission data, under the assumption that essential communications will be provided by low-rate, high availability RF. For both the RF and optical systems, the required EIRP, for a given data rate and a given distance, was achieved by a design that realized the lowest possible communications subsystem mass (power + aperture) consistent with achieving the lowest technology risk. A key conclusion of this paper is that optical communications has great potential for high data rates and distances of 2.67 AU and beyond, but requires R&D and flight demonstrations to prove out technologies.

  12. Detection Performance of Upgraded "Polished Panel" Optical Receiver Concept on the Deep-Space Network's 34 Meter Research Antenna

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    2012-01-01

    The development and demonstration of a "polished panel" optical receiver concept on the 34 meter research antenna of the Deep Space Network (DSN) has been the subject of recent papers. This concept would enable simultaneous reception of optical and microwave signals by retaining the original shape of the main reflector for microwave reception, but with the aluminum panels polished to high reflectivity to enable focusing of optical signal energy as well. A test setup has been installed on the DSN's 34 meter research antenna at Deep Space Station 13 (DSS-13) of NASA's Goldstone Communications Complex in California, and preliminary experimental results have been obtained. This paper describes the results of our latest efforts to improve the point-spread function (PSF) generated by a custom polished panel, in an attempt to reduce the dimensions of the PSF, thus enabling more precise tracking and improved detection performance. The design of the new mechanical support structure and its operation are described, and the results quantified in terms of improvements in collected signal energy and optical communications performance, based on data obtained while tracking the planet Jupiter with the 34 meter research antenna at DSS-13.

  13. First autonomous bio-optical profiling float in the Gulf of Mexico reveals dynamic biogeochemistry in deep waters.

    PubMed

    Green, Rebecca E; Bower, Amy S; Lugo-Fernández, Alexis

    2014-01-01

    Profiling floats equipped with bio-optical sensors well complement ship-based and satellite ocean color measurements by providing highly-resolved time-series data on the vertical structure of biogeochemical processes in oceanic waters. This is the first study to employ an autonomous profiling (APEX) float in the Gulf of Mexico for measuring spatiotemporal variability in bio-optics and hydrography. During the 17-month deployment (July 2011 to December 2012), the float mission collected profiles of temperature, salinity, chlorophyll fluorescence, particulate backscattering (bbp), and colored dissolved organic matter (CDOM) fluorescence from the ocean surface to a depth of 1,500 m. Biogeochemical variability was characterized by distinct depth trends and local "hot spots", including impacts from mesoscale processes associated with each of the water masses sampled, from ambient deep waters over the Florida Plain, into the Loop Current, up the Florida Canyon, and eventually into the Florida Straits. A deep chlorophyll maximum (DCM) occurred between 30 and 120 m, with the DCM depth significantly related to the unique density layer ρ = 1023.6 (R2 = 0.62). Particulate backscattering, bbp, demonstrated multiple peaks throughout the water column, including from phytoplankton, deep scattering layers, and resuspension. The bio-optical relationship developed between bbp and chlorophyll (R2 = 0.49) was compared to a global relationship and could significantly improve regional ocean-color algorithms. Photooxidation and autochthonous production contributed to CDOM distributions in the upper water column, whereas in deep water, CDOM behaved as a semi-conservative tracer of water masses, demonstrating a tight relationship with density (R2 = 0.87). In the wake of the Deepwater Horizon oil spill, this research lends support to the use of autonomous drifting profilers as a powerful tool for consideration in the design of an expanded and integrated observing network for

  14. First Autonomous Bio-Optical Profiling Float in the Gulf of Mexico Reveals Dynamic Biogeochemistry in Deep Waters

    PubMed Central

    Green, Rebecca E.; Bower, Amy S.; Lugo-Fernández, Alexis

    2014-01-01

    Profiling floats equipped with bio-optical sensors well complement ship-based and satellite ocean color measurements by providing highly-resolved time-series data on the vertical structure of biogeochemical processes in oceanic waters. This is the first study to employ an autonomous profiling (APEX) float in the Gulf of Mexico for measuring spatiotemporal variability in bio-optics and hydrography. During the 17-month deployment (July 2011 to December 2012), the float mission collected profiles of temperature, salinity, chlorophyll fluorescence, particulate backscattering (bbp), and colored dissolved organic matter (CDOM) fluorescence from the ocean surface to a depth of 1,500 m. Biogeochemical variability was characterized by distinct depth trends and local “hot spots”, including impacts from mesoscale processes associated with each of the water masses sampled, from ambient deep waters over the Florida Plain, into the Loop Current, up the Florida Canyon, and eventually into the Florida Straits. A deep chlorophyll maximum (DCM) occurred between 30 and 120 m, with the DCM depth significantly related to the unique density layer ρ = 1023.6 (R2 = 0.62). Particulate backscattering, bbp, demonstrated multiple peaks throughout the water column, including from phytoplankton, deep scattering layers, and resuspension. The bio-optical relationship developed between bbp and chlorophyll (R2 = 0.49) was compared to a global relationship and could significantly improve regional ocean-color algorithms. Photooxidation and autochthonous production contributed to CDOM distributions in the upper water column, whereas in deep water, CDOM behaved as a semi-conservative tracer of water masses, demonstrating a tight relationship with density (R2 = 0.87). In the wake of the Deepwater Horizon oil spill, this research lends support to the use of autonomous drifting profilers as a powerful tool for consideration in the design of an expanded and integrated observing network

  15. Adaptive optics microscopy enhances image quality in deep layers of CLARITY processed brains of YFP-H mice

    NASA Astrophysics Data System (ADS)

    Reinig, Marc R.; Novack, Samuel W.; Tao, Xiaodong; Ermini, Florian; Bentolila, Laurent A.; Roberts, Dustin G.; MacKenzie-Graham, Allan; Godshalk, S. E.; Raven, M. A.; Kubby, Joel

    2016-03-01

    Optical sectioning of biological tissues has become the method of choice for three-dimensional histological analyses. This is particularly important in the brain were neurons can extend processes over large distances and often whole brain tracing of neuronal processes is desirable. To allow deeper optical penetration, which in fixed tissue is limited by scattering and refractive index mismatching, tissue-clearing procedures such as CLARITY have been developed. CLARITY processed brains have a nearly uniform refractive index and three-dimensional reconstructions at cellular resolution have been published. However, when imaging in deep layers at submicron resolution some limitations caused by residual refractive index mismatching become apparent, as the resulting wavefront aberrations distort the microscopic image. The wavefront can be corrected with adaptive optics. Here, we investigate the wavefront aberrations at different depths in CLARITY processed mouse brains and demonstrate the potential of adaptive optics to enable higher resolution and a better signal-to-noise ratio. Our adaptive optics system achieves high-speed measurement and correction of the wavefront with an open-loop control using a wave front sensor and a deformable mirror. Using adaptive optics enhanced microscopy, we demonstrate improved image quality wavefront, point spread function, and signal to noise in the cortex of YFP-H mice.

  16. Surface Photometry of Local Volume Galaxies

    NASA Astrophysics Data System (ADS)

    Sakai, Shoko; van Zee, Liese; Lee, Janice C.; Kennicutt, Robert C.; Funes, Jose G.

    2009-08-01

    We propose to obtain UBVR images of a statistically complete sample of spiral and irregular galaxies in the Local Volume Legacy (LVL) survey to investigate the correlation between past star formation activity and other physical properties such as SFR, dust content, and metallicity. The proposed optical imaging observations of 34 galaxies (27 southern, 7 northern) will be combined with existing UV, H(alpha), and IR observations, and will serve to nearly complete the optical imaging coverage of the full LVL sample of 258 galaxies. As expected for a volume limited sample, the majority of galaxies targeted here are low luminosity dwarf galaxies. The observed optical colors, in addition to optical-IR colors, will be compared with stellar population models to estimate the past history of star formation in these low mass galaxies and to provide constraints on the stellar mass-to-light ratios. The observed surface photometry will also allow us to study the photometric properties, the morphology, and spatial distributions of the different stellar populations in these low mass systems.

  17. In-situ formation compaction monitoring in deep reservoirs by use of fiber optics

    NASA Astrophysics Data System (ADS)

    Murai, Daisuke; Kunisue, Shoji; Higuchi, Tomoyuki; Kokubo, Tatsuo

    2013-04-01

    1. Background The Southern Kanto gas field, the largest field of natural gas dissolved in water in Japan, is located primarily under the Chiba Prefecture. In this field 8 companies produce 460*10^6m3/y of natural gas. In addition, the concentration of the iodine in the brine is almost 2000 times that in seawater and the iodine as well as natural gas is collected from the brine. Iodine is industrially useful and essential for the human body. About 30% of world production is produced in this area in recent years. On the other hand, the land subsidence has become the big problem since 1965 and more than 10cm/mm of land subsidence was observed by leveling in 1972. The natural gas and iodine producers in this area have made a land subsidence prevention agreement with the local government and made effort to prevent and control land subsidence. Although their pumping brine for the gas and the iodine production is inferred to be the main cause of land subsidence from that time, the ratio of the formation compaction caused by pumping brine in the total land subsidence hasn't been well known. Therefore, the measurement of the actual formation compaction has become an important technological issue for the companies and they jointly have developed a new monitoring system for the formation compaction. 2. Contents (1) By using fiber optics technology, we have developed a world's first monitoring system which measures each of the in-situ formation compactions continuously without running tools into the well. (2) In order to check a reliability of this system and the problems when construction, we carried out the preliminary test. We installed the prototype system in the shallow observation well with a depth of 80 m and measured the actual formation compaction. The water well was drilled at the 10m away from the observation well and the formation was artificially compacted by pumping groundwater from it. (3) We installed the monitoring system in the deep observation well with a

  18. PSF reconstruction for AO photometry and astrometry

    NASA Astrophysics Data System (ADS)

    Ascenso, J.; Neichel, B.; Silva, M.; Fusco, T.; Garcia, P.

    2015-12-01

    Extracting accurate photometry (and astrometry) from images taken with adaptive optics assisted instruments is particularly challenging. Current post-processing tools are not prepared to achieve high accuracy from AO data, especially in limiting cases of crowded fields and marginally resolved sources. We quantify the limitations of these tools with synthetic images, and present a proof-of-concept study showing the potential of using reconstructed PSFs from the (GL)AO system telemetry to increase the measured photometric accuracy. We show that the photometric accuracy is significantly improved with a good PSF reconstruction in considerably crowded regions. We demonstrate the need for a dedicated post-processing tool that incorporates available information about the PSF, as well as the ability to adjust to the spatial variations of the PSF characteristic of AO data.

  19. Supernova Classification Using Swift UVOT Photometry

    NASA Astrophysics Data System (ADS)

    Smith, Madison; Brown, Peter J.

    2017-01-01

    With the great influx of supernova discoveries over the past few years, the observation time needed to acquire the spectroscopic data needed to classify supernova by type has become unobtainable. Instead, using the photometry of supernovae could greatly reduce the amount of time between discovery and classification. For this project we looked at the relationship between colors and supernova types through machine learning packages in Python. Using data from the Swift Ultraviolet/Optical Telescope (UVOT), each photometric point was assigned values corresponding to colors, absolute magnitudes, and the relative times from the peak brightness in several filters. These values were fed into three classifying methods, the nearest neighbors, decision tree, and random forest methods. We will discuss the success of these classification systems, the optimal filters for photometric classification, and ways to improve the classification.

  20. Spectroscopy and Photometry of MWC 137

    NASA Astrophysics Data System (ADS)

    Alimardanova, F.; Miroshnichenko, A. S.; Zharikov, S. V.; Rudy, R. J.; Manset, N.; Kusakin, A. V.; Kuratov, K. S.; Khokhlov, S.

    2017-02-01

    MWC 137 is an object with a strong emission-line spectrum associated with an 1'-size H Imall> region Sharpless 266. It was included in a catalog of planetary nebulae in 1967, in the first list of objects with the B[e] phenomenon in 1976, and in a list of Herbig Ae/Be stars in 1984. A recent analysis of the stellar and nebular spectra of MWC 137 by several authors suggested that it is most likely a B[e] supergiant located at a distance 4-6 kpc away from the Sun. No high-resolution spectra of the object have been published so far. We present the results of our analysis of high-resolution optical spectra of MWC 137 obtained in 2004-2016 and UBVRI photometry.

  1. A COMPREHENSIVE STUDY OF DETECTABILITY AND CONTAMINATION IN DEEP RAPID OPTICAL SEARCHES FOR GRAVITATIONAL WAVE COUNTERPARTS

    SciTech Connect

    Cowperthwaite, P. S.; Berger, E.

    2015-11-20

    The first direct detection of gravitational waves (GWs) by the ground-based Advanced LIGO/Virgo interferometers is expected to occur within the next few years. These interferometers are designed to detect the mergers of compact object binaries composed of neutron stars and/or black holes to a fiducial distance of ∼200 Mpc and a localization region of ∼100 deg{sup 2}. To maximize the science gains from such GW detections it is essential to identify electromagnetic counterparts. Among the wide range of proposed counterparts, the most promising is optical/IR emission powered by the radioactive decay of r-process elements synthesized in the neutron-rich merger ejecta—a “kilonova.” Here we present detailed simulated observations that encompass a range of strategies for kilonova searches during GW follow-up. We utilize these simulations to assess both the detectability of kilonovae and our ability to distinguish them from a wide range of contaminating transients in the large GW localization regions. We find that if pre-existing deep template images for the GW localization region are available, then nightly observations to a depth of i ≈ 24 mag and z ≈ 23 mag are required to achieve a 95% detection rate; observations that commence within ∼12 hr of trigger will also capture the kilonova peak and provide stronger constraints on the ejecta properties. We also find that kilonovae can be robustly separated from other known and hypothetical types of transients utilizing cuts on color (i − z ≳ 0.3 mag) and rise time (t{sub rise} ≲ 4 days). In the absence of a pre-existing template the observations must reach ∼1 mag deeper to achieve the same kilonova detection rate, but robust rejection of contaminants can still be achieved. Motivated by the results of our simulations we discuss the expected performance of current and future wide-field telescopes in achieving these observational goals, and find that prior to LSST the Dark Energy Camera on the Blanco 4 m

  2. Heavy Element Abundances in Planetary Nebulae from Deep Optical Echelle Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mashburn, Amanda; Sterling, Nicholas C.; Dinerstein, Harriet L.; Garofali, Kristen; Jensema, Rachael; Turbyfill, Amanda; Wieser, Hannah-Marie N.; Reed, Evan C.; Redfield, Seth

    2016-01-01

    We present the abundances of neutron(n)-capture elements (atomic number Z > 30) and iron determined from deep optical echelle spectroscopy of 14 Galactic planetary nebulae (PNe). The spectra were obtained with the 2D-coudé spectrograph on the 2.7-m Harlan J. Smith telescope at McDonald Observatory. The abundances of n-capture elements can be enhanced in PNe due to slow n-capture nucleosynthesis in the progenitor asymptotic giant branch (AGB) stars. The high spectral resolution of these data (R = 36,700) allow most n-capture element emission lines to be resolved from other nebular and telluric features. We detect Kr in all of the observed PNe (with multiple ions detected in several objects), while Br, Rb, and Xe were each detected in 4--5 objects. Using the new Kr ionization correction factors (ICFs) of Sterling et al. (2015, ApJS, 218, 25), we find [Kr/O] abundances ranging from 0.05 to 1.1 dex. We utilize approximate ICFs for the other n-capture elements, and find slightly lower enrichments for Br and Rb (-0.1 to 0.7 dex), while Xe is enhanced relative to solar by factors of two to 30. The [Xe/Kr] ratios range from -0.3 to 1.4 dex, indicating a significant range in neutron exposures in PN progenitor stars. Interestingly, the largest [Xe/Kr] ratio is found in the thick-disk PN NGC 6644, which has a lower metallicity than the other observed PNe. We detect iron emission lines in all but one target. Fe can be depleted into dust grains in ionized nebulae, and its abundance thus provides key information regarding dust-to-gas ratios and grain destruction processes. We find that [Fe/O] ranges from -1.3 to -0.7 dex in the observed PNe, a smaller spread of depletion factors than found in recent studies (Delgado-Inglada & Rodriguez 2014, ApJ, 784, 173) though this may be due in part to our smaller sample. These data are part of a larger study of heavy elements in PNe, which will provide more accurate determinations of n-capture element abundances than previous estimates in

  3. Optical Multicolor Photometry of Spectrophotometric Standard Stars

    NASA Astrophysics Data System (ADS)

    Landolt, Arlo U.; Uomoto, Alan K.

    2007-03-01

    Photoelectric data on the Johnson-Kron-Cousins UBVRI broadband photometric system are provided for a set of stars that have been used as spectrophotometric standard stars for the Hubble Space Telescope.

  4. Rapid Optical Photometry of V404 Cyg

    NASA Astrophysics Data System (ADS)

    Hynes, R. I.; Robinson, E. L.; Morales, J.

    2015-06-01

    We observed the outbursting black hole X-ray transient V404 Cyg (GCN #17929, #17931, #17933, #17938, #17940, #17944, #17945, #17946, #17948; ATel #7646, #7647, #7650, #7655, #7658, #7659, #7661, #7662, #7663, #7665, #7666, #7667, #7669, #7671, #7674) for about four hours on 2015 June 18.26-18.44 UT using the Argos photometer on the 2.1m Otto Struve Telescope at McDonald Observatory.

  5. THE ARAUCARIA PROJECT. A DISTANCE DETERMINATION TO THE LOCAL GROUP SPIRAL M33 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES

    SciTech Connect

    Gieren, Wolfgang; Pietrzynski, Grzegorz; Graczyk, Dariusz E-mail: pietrzyn@hubble.cfm.udec.cl; and others

    2013-08-10

    Motivated by an amazing range of reported distances to the nearby Local Group spiral galaxy M33, we have obtained deep near-infrared photometry for 26 long-period Cepheids in this galaxy with the ESO Very Large Telescope. From the data, we constructed period-luminosity relations in the J and K bands which together with previous optical VI photometry for the Cepheids by Macri et al. were used to determine the true distance modulus of M33, and the mean reddening affecting the Cepheid sample with the multiwavelength fit method developed in the Araucaria Project. We find a true distance modulus of 24.62 for M33, with a total uncertainty of {+-}0.07 mag which is dominated by the uncertainty on the photometric zero points in our photometry. The reddening is determined as E(B - V) = 0.19 {+-} 0.02, in agreement with the value used by the Hubble Space Telescope Key Project of Freedman et al. but in some discrepancy with other recent determinations based on blue supergiant spectroscopy and an O-type eclipsing binary which yielded lower reddening values. Our derived M33 distance modulus is extremely insensitive to the adopted reddening law. We show that the possible effects of metallicity and crowding on our present distance determination are both at the 1%-2% level and therefore minor contributors to the total uncertainty of our distance result for M33.

  6. Physical Properties of White Dwarfs from Multi-Band Photometry

    NASA Astrophysics Data System (ADS)

    Raddi, R.

    2017-03-01

    We describe a hierarchical Bayesian model to measure the physical parameters (mass, cooling age, distance, interstellar extinction) of single white dwarfs using only multi-band UV to IR photometry. We test our model on a set of known white dwarfs with well-assessed atmospheric parameters, determined via optical spectroscopy. Looking forward to the results of the ESA Gaia mission, we derive the posterior distributions of white dwarf parameters in two different scenarios with known or unknown parallaxes.

  7. Deep Proton Writing for the rapid prototyping of polymer micro-components for optical interconnects and optofluidics

    NASA Astrophysics Data System (ADS)

    Van Erps, Jürgen; Vervaeke, Michael; Ottevaere, Heidi; Hermanne, Alex; Thienpont, Hugo

    2013-07-01

    The use of photonics in data communication and numerous other industrial applications brought plenty of prospects for innovation and opened up different unexplored market opportunities. This is a major driving force for the fabrication of micro-optical and micro-mechanical structures and their accurate alignment and integration into opto-mechanical modules and systems. To this end, we present Deep Proton Writing (DPW) as a powerful rapid prototyping technology for such micro-components. The DPW process consists of bombarding polymer samples (PMMA or SU-8) with swift protons, which results after chemical processing steps in high-quality micro-optical components. One of the strengths of the DPW micro-fabrication technology is the ability to fabricate monolithic building blocks that include micro-optical and mechanical functionalities which can be precisely integrated into more complex photonic systems. In this paper we comment on how we shifted from using 8.3 to 16.5 MeV protons for DPW and give some examples of micro-optical and micro-mechanical components recently fabricated through DPW, targeting applications in optical interconnections and in optofluidics.

  8. High speed low noise multiplexed three color absorbance photometry.

    PubMed

    Dadesh, Khaled M; Kurup, G K; Basu, Amar S

    2011-01-01

    Multispectral photometry is often required to distinguish samples in flow injection analysis and flow cytometry; however, the cost of multiple light detectors, filters, and optical paths contribute to the high cost of multicolor and spectral detection systems. This paper describes frequency division multiplexing (FDM), a simple approach for performing multi-wavelength absorbance photometry with a single light detector and a single interrogation window. In previous efforts, modulation frequencies were <10 KHz, resulting in a detector bandwidth of <20 Hz. This paper presents a high frequency FDM circuit which can increase the oscillation frequencies to several 100 KHz, improving the detection bandwidth by a factor of 10 while still maintaining low cost. Light from 3 different LED sources are encoded into unique frequency channels, passed through the detection cell, and later demodulated using phase-sensitive electronics. Electronic multiplexing couples all light sources into a single optical train without spectral filters. Theory and high frequency considerations are demonstrated. Simultaneous three color absorbance detection is demonstrated in solutions and in flowing droplet microreactors. This technique can potentially reduce the cost of multicolor photometry by replacing expensive optical components with low-cost electronics.

  9. Classical photometry of prefractal surfaces.

    PubMed

    Shkuratov, Yuriy; Petrov, Dmitriy; Videen, Gorden

    2003-11-01

    Using the scale invariance of classical photometry, we develop an approach to finding the photometric function of prefractal structures that form a random topography. The photometric function of the prefractal surfaces is found as the general solution of the resulting differential equation in partial derivatives. The function depends on two parameters: the number of hierarchical levels of the prefractal structures and the roughness parameter of the single-level generation. As a limiting case, the approach includes our previous theory that considered fractoids.

  10. Characterisation of the Gaia photometry

    NASA Astrophysics Data System (ADS)

    Carrasco, J. M.; Jordi, C.; Fabricius, C.; Voss, H.; Weiler, M.

    2014-07-01

    Our team at the University of Barcelona has contributed since the early phases of the mission to the definition, evaluation and calibration modelling of the Gaia photometry. To maximise the Gaia scientific exploitation, we have frequently shared many different tools and data with the astronomical community. Among this information we have defined several relationships among colours involving Gaia magnitudes and colours from other commonly used photometric systems (Johnson-Cousins, SDSS, Hipparcos, Tycho and 2MASS) for several types of stars (including white dwarfs). These relationships can be used for planning scientific exploitation of Gaia data, performing simulations of the Gaia-like sky, planning ground-based complementary observations and for building catalogues with auxiliary validation data. During the commissioning phase our team (as part of the Payload Experts group) has been intensively checking the first photometric data to analyse the health and properties of the real instrument. These preliminary analyses allowed us to monitor the throughput variations with time, assess the spectral resolution and re-evaluate the performances of the end-of-mission photometry. The Payload Experts group activities continue beyond the commissioning phase aiming to optimize the operations onboard for maximizing the scientific return. Some example of first spectra and photometry are shown.

  11. In-vivo monitoring of tissue oxygen saturation in deep brain structures using a single fiber optical system

    PubMed Central

    Yu, Linhui; Wu, Ying; Dunn, Jeff F.; Murari, Kartikeya

    2016-01-01

    We propose a single fiber optical system for monitoring tissue oxygen saturation (sO2) based on continuous-wave reflectance spectroscopy in the visible wavelengths. The system is designed for measurements in deep brain structures by stereotaxically implanting the 200 μm-core fiber probe into the tissue of interest. Monte Carlo (MC) simulations were used to estimate the measurement tissue volume between 0.02–0.03 mm3. Experiments in an optical phantom indicated the system had a root mean squared error (RMSE) of 4.21% compared with a commercial fluorescence-based tissue oxygen partial pressure measuring system. Finally, we used the system for continuously monitoring tissue sO2 from a highly-localized volume in anesthetized mice. PMID:27896007

  12. Hot-embossing replication of self-centering optical fiber alignment structures prototyped by deep proton writing

    NASA Astrophysics Data System (ADS)

    Ebraert, Evert; Wissmann, Markus; Guttmann, Markus; Kolew, Alexander; Worgull, Matthias; Barié, Nicole; Schneider, Marc; Hofmann, Andreas; Beri, Stefano; Watté, Jan; Thienpont, Hugo; Van Erps, Jürgen

    2016-07-01

    This paper presents the hot-embossing replication of self-centering fiber alignment structures for high-precision, single-mode optical fiber connectors. To this end, a metal mold insert was fabricated by electroforming a polymer prototype patterned by means of deep proton writing (DPW). To achieve through-hole structures, we developed a postembossing process step to remove the residual layer inherently present in hot-embossed structures. The geometrical characteristics of the hot-embossed replicas are compared, before and after removal of the residual layer, with the DPW prototypes. Initial measurements on the optical performance of the replicas are performed. The successful replication of these components paves the way toward low-cost mass replication of DPW-fabricated prototypes in a variety of high-tech plastics.

  13. Transmitters and receivers in free space optical communications for Deep Space links

    NASA Technical Reports Server (NTRS)

    Beebe, J.

    2003-01-01

    Two of the many research areas integral making a Mars-Earth optical communication link a reality are optical antenna design and laser transmitter design. This paper addresses areas of both of these by exploring a mode-matched design for a cavity-dumped communications laser, and by reporting on the initial stages of the analysis of an existing 100 inch telescope for use as an optical communications receiver.

  14. The regime of aerosol optical depth over Central Asia based on MODIS Aqua Deep Blue data

    NASA Astrophysics Data System (ADS)

    Floutsi, Athina; KorrasCarraca, Marios; Matsoukas, Christos; Biskos, George

    2015-04-01

    Atmospheric aerosols, both natural and anthropogenic, can affect the regional and global climate through their direct, indirect, and semi-direct effects on the radiative energy budget of the Earth-atmosphere system. To quantify these effects it is therefore important to determine the aerosol load, and an effective way to do that is by measuring the aerosol optical depth (AOD). In this study we investigate the spatial and temporal variability of the AOD over the climatically sensitive region of Central Asia (36° N - 50° N, 46° E - 75° E), which has significant sources of both natural and anthropogenic particles. The primary source of anthropogenic particles is fossil fuel combustion occurring mainly at oil refineries in the Caspian Sea basin. Natural particles originate mostly from the two deserts in the region (namely Kara-Kum and Kyzyl-Kum), where persistent dust activity is observed. Another source is the Aral Sea region, which due to its phenomenal desertification also drives an intense salt and dust transport from the exposed sea-bed to the surrounding regions. This transport is of particular interest because of health-hazardous materials contained in the Aral Sea sea-bed. For our analysis we use Level-3 daily MODIS - Aqua Dark Target - Deep Blue combined product, from the latest MODIS collection (006), available in 1° x 1° resolution (about 100 km x 100 km) over the period 2002-2014.Our first results indicate a significant spatial variability of the aerosol load over the study region. The data also show a clear seasonal cycle, with large aerosol load being associated with strong dust activity during spring and summer (AOD up to 0.5), and low during autumn and winter (AOD up to 0.4). In spring and summer significant aerosol load is observed in the Garabogazköl basin, Northeast and South-southeast Caspian Sea (offshore North Iran and Azerbaijan), as well as southwest of the Aral Sea. In the later region, the high AOD values can be explained by export of

  15. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. X. ULTRAVIOLET TO INFRARED PHOTOMETRY OF 117 MILLION EQUIDISTANT STARS

    SciTech Connect

    Williams, Benjamin F.; Dalcanton, Julianne J.; Weisz, Daniel R.; Byler, Nell; Johnson, L. C. E-mail: jd@astro.washington.edu E-mail: lcjohnso@astro.washington.edu; and others

    2014-11-01

    We have measured stellar photometry with the Hubble Space Telescope Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys in near ultraviolet (F275W, F336W), optical (F475W, F814W), and near infrared (F110W, F160W) bands for 117 million resolved stars in M31. As part of the Panchromatic Hubble Andromeda Treasury survey, we measured photometry with simultaneous point-spread function (PSF) fitting across all bands and at all source positions after precise astrometric image alignment (<5-10 mas accuracy). In the outer disk, the photometry reaches a completeness-limited depth of F475W ∼ 28, while in the crowded, high surface brightness bulge, the photometry reaches F475W ∼ 25. We find that simultaneous photometry and optimized measurement parameters significantly increase the detection limit of the lowest-resolution filters (WFC3/IR) providing color-magnitude diagrams (CMDs) that are up to 2.5 mag deeper when compared with CMDs from WFC3/IR photometry alone. We present extensive analysis of the data quality including comparisons of luminosity functions and repeat measurements, and we use artificial star tests to quantify photometric completeness, uncertainties and biases. We find that the largest sources of systematic error in the photometry are due to spatial variations in the PSF models and charge transfer efficiency corrections. This stellar catalog is the largest ever produced for equidistant sources, and is publicly available for download by the community.

  16. Ti:sapphire-pumped deep-infrared femtosecond optical parametric oscillator based on CdSiP2.

    PubMed

    Ramaiah-Badarla, V; Chaitanya Kumar, S; Esteban-Martin, A; Devi, K; Zawilski, K T; Schunemann, P G; Ebrahim-Zadeh, M

    2016-04-15

    We report on a femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on the Kerr-lens-mode-locked Ti:sapphire laser as the pump source. By deploying a novel cascaded intracavity arrangement, comprising a femtosecond OPO based on the nonlinear crystal, CdSiP2, synchronously pumped internal to a MgO:PPLN femtosecond OPO, we have generated broadly tunable radiation across 5958-8117 nm using rapid static cavity delay tuning, with a maximum power of 64 μW at 6791 nm, limited by the absorption in mirror substrates as well as polarization-dependent intracavity losses. The deep-IR idler power exhibits excellent passive stability of better than 1.1% rms over 2 h, with a spectral bandwidth as large as ∼650 nm at ∼6800 nm. The demonstrated concept is generic and can be similarly deployed in other operating time scales and wavelength regions, also using different laser pump sources and nonlinear materials.

  17. Crystal growth and optical characteristics of beryllium-free polyphosphate, KLa(PO3)4, a possible deep-ultraviolet nonlinear optical crystal

    NASA Astrophysics Data System (ADS)

    Shan, Pai; Sun, Tongqing; Chen, Hong; Liu, Hongde; Chen, Shaolin; Liu, Xuanwen; Kong, Yongfa; Xu, Jingjun

    2016-04-01

    Deep-ultraviolet nonlinear optical crystals are of great importance as key materials in generating coherent light with wavelength below 200 nm through cascaded frequency conversion of solid-state lasers. However, the solely usable crystal in practice, KBe2BO3F2 (KBBF), is still commercially unavailable because of the high toxicity of beryllium-containing and the extreme difficulty of crystal growth. Here, we report the crystal growth and characteristics of an beryllium-free polyphosphate, KLa(PO3)4. Centimeter-sized single crystals have been easily obtained by the flux method and slow-cooling technique. The second-harmonic generation efficiency of KLa(PO3)4 powder is 0.7 times that of KH2PO4; moreover, the KLa(PO3)4 crystal is phase-matchable. Remarkably, the KLa(PO3)4 crystal exhibits an absorption edge of 162 nm, which is the shortest among phase-matchable phosphates so far. These attributes make KLa(PO3)4 a possible deep-ultraviolet nonlinear optical crystal. An analysis of the dipole moments of the polyhedra and theoretical calculations by density functional theory were made to elucidate the structure-properties relationships of KLa(PO3)4.

  18. Crystal growth and optical characteristics of beryllium-free polyphosphate, KLa(PO3)4, a possible deep-ultraviolet nonlinear optical crystal

    PubMed Central

    Shan, Pai; Sun, Tongqing; Chen, Hong; Liu, Hongde; Chen, Shaolin; Liu, Xuanwen; Kong, Yongfa; Xu, Jingjun

    2016-01-01

    Deep-ultraviolet nonlinear optical crystals are of great importance as key materials in generating coherent light with wavelength below 200 nm through cascaded frequency conversion of solid-state lasers. However, the solely usable crystal in practice, KBe2BO3F2 (KBBF), is still commercially unavailable because of the high toxicity of beryllium-containing and the extreme difficulty of crystal growth. Here, we report the crystal growth and characteristics of an beryllium-free polyphosphate, KLa(PO3)4. Centimeter-sized single crystals have been easily obtained by the flux method and slow-cooling technique. The second-harmonic generation efficiency of KLa(PO3)4 powder is 0.7 times that of KH2PO4; moreover, the KLa(PO3)4 crystal is phase-matchable. Remarkably, the KLa(PO3)4 crystal exhibits an absorption edge of 162 nm, which is the shortest among phase-matchable phosphates so far. These attributes make KLa(PO3)4 a possible deep-ultraviolet nonlinear optical crystal. An analysis of the dipole moments of the polyhedra and theoretical calculations by density functional theory were made to elucidate the structure-properties relationships of KLa(PO3)4. PMID:27126353

  19. Crystal growth and optical characteristics of beryllium-free polyphosphate, KLa(PO3)4, a possible deep-ultraviolet nonlinear optical crystal.

    PubMed

    Shan, Pai; Sun, Tongqing; Chen, Hong; Liu, Hongde; Chen, Shaolin; Liu, Xuanwen; Kong, Yongfa; Xu, Jingjun

    2016-04-29

    Deep-ultraviolet nonlinear optical crystals are of great importance as key materials in generating coherent light with wavelength below 200 nm through cascaded frequency conversion of solid-state lasers. However, the solely usable crystal in practice, KBe2BO3F2 (KBBF), is still commercially unavailable because of the high toxicity of beryllium-containing and the extreme difficulty of crystal growth. Here, we report the crystal growth and characteristics of an beryllium-free polyphosphate, KLa(PO3)4. Centimeter-sized single crystals have been easily obtained by the flux method and slow-cooling technique. The second-harmonic generation efficiency of KLa(PO3)4 powder is 0.7 times that of KH2PO4; moreover, the KLa(PO3)4 crystal is phase-matchable. Remarkably, the KLa(PO3)4 crystal exhibits an absorption edge of 162 nm, which is the shortest among phase-matchable phosphates so far. These attributes make KLa(PO3)4 a possible deep-ultraviolet nonlinear optical crystal. An analysis of the dipole moments of the polyhedra and theoretical calculations by density functional theory were made to elucidate the structure-properties relationships of KLa(PO3)4.

  20. Multi-channel fiber photometry for population neuronal activity recording.

    PubMed

    Guo, Qingchun; Zhou, Jingfeng; Feng, Qiru; Lin, Rui; Gong, Hui; Luo, Qingming; Zeng, Shaoqun; Luo, Minmin; Fu, Ling

    2015-10-01

    Fiber photometry has become increasingly popular among neuroscientists as a convenient tool for the recording of genetically defined neuronal population in behaving animals. Here, we report the development of the multi-channel fiber photometry system to simultaneously monitor neural activities in several brain areas of an animal or in different animals. In this system, a galvano-mirror modulates and cyclically couples the excitation light to individual multimode optical fiber bundles. A single photodetector collects excited light and the configuration of fiber bundle assembly and the scanner determines the total channel number. We demonstrated that the system exhibited negligible crosstalk between channels and optical signals could be sampled simultaneously with a sample rate of at least 100 Hz for each channel, which is sufficient for recording calcium signals. Using this system, we successfully recorded GCaMP6 fluorescent signals from the bilateral barrel cortices of a head-restrained mouse in a dual-channel mode, and the orbitofrontal cortices of multiple freely moving mice in a triple-channel mode. The multi-channel fiber photometry system would be a valuable tool for simultaneous recordings of population activities in different brain areas of a given animal and different interacting individuals.

  1. Sensitive Spitzer Photometry of Supermassive Black Holes at the Final Stage of Adolescence

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad; Netzer, Hagai; Mor, Rivay; Trakhtenbrot, Benny

    2011-05-01

    We propose to obtain sensitive Spitzer snapshot observations of a unique sample of 35 Sloan Digital Sky Survey quasars at redshift 4.8 for which we obtained reliable, Mg II-based determinations of the supermassive black hole (SMBH) mass and normalized accretion rate (L/L_Edd). These quasars appear to mark the final stage of SMBH `adolescence' in the history of the Universe as their SMBHs are significantly less massive and their L/L_Edd values are significantly higher with respect to their counterparts at lower redshifts. Our observations will provide both 1) deep coverage of the fields around these quasars which will be utilized as crucial priors for our approved Herschel/SPIRE observations of these sources, and 2) coverage of the rest-frame optical SEDs of these fast accreting quasars. The results will maximize our ability to measure the star-formation rate in the host galaxies of these quasars using Herschel. We will thus be able to investigate correlations between SMBH growth and star-forming activity in the early Universe. The Spitzer photometry will also provide invaluable information about the shape of the rest-frame optical continuum in these quasars which will be used to search for extreme disk properties that may be signatures of the remarkably high accretion rates in these sources.

  2. Probing interstellar turbulence in cirrus with deep optical imaging: no sign of energy dissipation at 0.01 pc scale

    NASA Astrophysics Data System (ADS)

    Miville-Deschênes, M.-A.; Duc, P.-A.; Marleau, F.; Cuillandre, J.-C.; Didelon, P.; Gwyn, S.; Karabal, E.

    2016-08-01

    Diffuse Galactic light has been observed in the optical since the 1930s. We propose that, when observed in the optical with deep imaging surveys, it can be used as a tracer of the turbulent cascade in the diffuse interstellar medium (ISM), down to scales of about 1 arcsec. Here we present a power spectrum analysis of the dust column density of a diffuse cirrus at high Galactic latitude (l ≈ 198°, b ≈ 32°) as derived from the combination of a MegaCam g-band image, obtained as part of the MATLAS large programme at the CFHT, with Planck radiance and WISE 12 μm data. The combination of these three datasets have allowed us to compute the density power spectrum of the H i over scales of more than three orders of magnitude. We found that the density field is well described by a single power law over scales ranging from 0.01 to 50 pc. The exponent of the power spectrum, γ = -2.9 ± 0.1, is compatible with what is expected for thermally bi-stable and turbulent H i. We did not find any steepening of the power spectrum at small scales indicating that the typical scale at which turbulent energy is dissipated in this medium is smaller than 0.01 pc. The ambipolar diffusion scenario that is usually proposed as the main dissipative agent, is consistent with our data only if the density of the cloud observed is higher than the typical values assumed for the cold neutral medium gas. We discuss the new avenue offered by deep optical imaging surveys for the study of the low density ISM structure and turbulence.

  3. Multicolor surface photometry of powerful radio galaxies

    SciTech Connect

    Smith, E.P.

    1988-01-01

    CCD images of 72 powerful radio galaxies have been obtained with the KPNO 2.1m, 4m and CTIO 4m telescopes utilizing B, V, and R filters to study the colors and other photometric properties of these large systems. The GASP software package was used for the data reduction and detailed 2-d surface photometry. In addition, image modeling techniques were employed to investigate the contributions to galaxy properties by point-like nuclear sources seen in some of these galaxies. It was found that powerful radio galaxies show a much higher frequency than normal bright ellipticals of having optical morphologies which deviate from elliptical symmetry. Approximately 50% of the sample exhibit non-elliptically symmetric isophotes. These prominent distortions are present at surface brightness levels of {le} 25 V mag/(arc sec){sup 2}. In addition, a large fraction ({approximately}50%) of the remaining radio galaxies without the aforementioned morphological peculiarities have large isophotal twists ({Delta}P.A. {ge} 10{degree}) or ellipticity gradients. Significantly {approximately}50% of the galaxies with strong optical emission lines in their spectra display optically peculiar structures very similar to those found by Toomre and Toomre (1972) in their simulations of interacting disk galaxies. The galaxies with weak emission lines in their spectra are less frequently ({approximately}10%) distorted from elliptical shape. Those that are exhibit features like isophote twists, double nuclei and close companion galaxies embedded in the radio galaxy optical isophotes. The (B-V) colors of many of the powerful radio galaxies with strong emission lines are blue relative to normal giant ellipticals at the same redshift.

  4. Surface photometry of comet P/Encke

    NASA Technical Reports Server (NTRS)

    Djorgovski, S.; Spinrad, H.

    1985-01-01

    A scheme to clean cometary digital images from offending background-star trails, and this technique has been applied to a pair of deep Kitt Peak 4-m plates of comet P/Encke, taken in October 1980. Simultaneous and subsequent digital spectra have been obtained at Lick Observatory. The non-polluted coma images show a strong asymmetric sunward-oriented fan/jet, and an extended and rounder (mostly gaseous) main coma, out to approximately 100,000 km radius. The stellar-trail point-spread function has a narrow width (sigma approximately 0.6 arcsec), so that spatial resolution better than approximately 300 km is achieved at the comet. The photometric gradient near the nucleus is very steep, strongly suggesting an icy-grain component which evaporates quickly (at radii equal to or less than 500 km) in the sunlight. Further from the nucleus, the profile becomes shallower, bluer, and more gas dominated. The effect of solar radiation pressure on C2, CN, and other molecules is probably responsible for the rounding of the outer, fainter isophotes. The source of the molecules is likely to be larger than the nucleus itself, and a substantial fraction may originate in the jet. The technique described here may also be applicable in surface photometry of galaxies, in cases where the heavy image pollution by foreground stars is present.

  5. Surface photometry of comet P/Encke

    NASA Astrophysics Data System (ADS)

    Djorgovski, S.; Spinrad, H.

    1985-05-01

    A scheme to clean cometary digital images from offending background-star trails, and this technique has been applied to a pair of deep Kitt Peak 4-m plates of comet P/Encke, taken in October 1980. Simultaneous and subsequent digital spectra have been obtained at Lick Observatory. The non-polluted coma images show a strong asymmetric sunward-oriented fan/jet, and an extended and rounder (mostly gaseous) main coma, out to approximately 100,000 km radius. The stellar-trail point-spread function has a narrow width (sigma approximately 0.6 arcsec), so that spatial resolution better than approximately 300 km is achieved at the comet. The photometric gradient near the nucleus is very steep, strongly suggesting an icy-grain component which evaporates quickly (at radii equal to or less than 500 km) in the sunlight. Further from the nucleus, the profile becomes shallower, bluer, and more gas dominated. The effect of solar radiation pressure on C2, CN, and other molecules is probably responsible for the rounding of the outer, fainter isophotes. The source of the molecules is likely to be larger than the nucleus itself, and a substantial fraction may originate in the jet. The technique described here may also be applicable in surface photometry of galaxies, in cases where the heavy image pollution by foreground stars is present.

  6. Infrared Photometry of 487 Sources in the Inner Regions of NGC 5128 (Centaurus A)

    NASA Astrophysics Data System (ADS)

    Alonso, M. Victoria; Minniti, Dante

    1997-04-01

    We study the sources present in the inner 3 kpc region of NGC 5128 (Cen A), most of which are star clusters of different ages. Photometry of archival Hubble Space Telescope WFPC images (F675W filter) is complemented with IR photometry (JHK' filters) obtained with the IRAC2B infrared array camera at the ESO/MPI 2.2 m telescope. From IR color maps we divide the field into two regions: a clear region outside the dust lane, and an obscured region well inside the dust lane of NGC 5128. In the unreddened region there is a great variety of sources such as globular clusters, star associations, and H II regions. These sources are not individual stars, which would be too faint to be resolved from ground-based telescopes. The vast majority of IR sources in the reddened region, where the dust lane dominates, are not seen at all in the deep HST images. The presence of large amounts of differential extinction makes it difficult to evaluate them. In total, there are 372 objects detected in the inner region of NGC 5128. From them, 125 objects are detected both in IR and HST frames. There are 247 IR sources without optical counterparts (47 in the clear region and 200 in the dust lane). Accounting for the small volume sampled, there must be a total of ~500 sources with K < 18 in the dust lane region. The distribution of these sources is rather uniform and not particularly centrally concentrated. This fact suggests that the majority of them are located in a disk, as would be expected if they are young associations or clusters. The degree of background and foreground contamination is evaluated using observations of a nearby field. We found 115 IR sources in this field. The nucleus itself is invisible in deep optical images, but it is clearly identified in the IR. In the region just south of the nucleus the extinction must be larger than AK = 3. In the clear region, where the effect of the dust lane is negligible, we have identified some objects as intermediate-age clusters containing

  7. Comparative Study of Optical and Radio-Frequency Communication Systems for a Deep-Space Mission

    NASA Technical Reports Server (NTRS)

    Hemmati, H.; Wilson, K.; Sue, M. K.; Harcke, L. J.; Wilhelm, M.; Chen, C.-C.; Lesh, J.; Feria, Y.; Rascoe, D.; Lansing, F.

    1997-01-01

    We have performed a study on telecommunication systems for a hypothetical mission to Mars. The objective of the study was to evaluate and compare the benefits that microwave-X-band (8.4 GHz) and Ka-band (32 GHz) - and optical communications technologies a afford to future missions. The telecommunication systems were required to return data after launch and in orbit at 2.7 AU with daily data volumes of 0.1, 1.0, or 10.0 Gbits (Gb). Spacecraft terminals capable of delivering each of the three data volumes were proposed and characterized in terms of mass, power consumption, size, and cost. The estimated parameters for X-band, Ka-band, and optical frequencies are compared and presented here. For all cases, the optical light terminal exhibits about 60 percent of the mass of the corresponding radio frequency (RF) subsystem. Power consumption is comparable for all three technologies at a 0.1 Gb/day data volume, but the power required at either Ka-band or optical is less than half of the X-band requirement at 10 Gb/day. These benefits can be obtained only with a suitable investment in reception facilities for Ka-band or optical frequencies.

  8. Deep-space navigation applications of improved ground-based optical astrometry

    NASA Technical Reports Server (NTRS)

    Null, G. W.; Owen, W. M., Jr.; Synnott, S. P.

    1992-01-01

    Improvements in ground-based optical astrometry will eventually be required for navigation of interplanetary spacecraft when these spacecraft communicate at optical wavelengths. Although such spacecraft may be some years off, preliminary versions of the astrometric technology can also be used to obtain navigational improvements for the Galileo and Cassini missions. This article describes a technology-development and observational program to accomplish this, including a cooperative effort with U.S. Naval Observatory Flagstaff Station. For Galileo, Earth-based astrometry of Jupiter's Galilean satellites may improve their ephemeris accuracy by a factor of 3 to 6. This would reduce the requirements for onboard optical navigation pictures, so that more of the data transmission capability (currently limited by high-gain antenna deployment problems) can be used for science data. Also, observations of European Space Agency (ESA) Hipparcos stars with asteroid 243 Ida may provide significantly improved navigation accuracy for a planned August 1993 Galileo spacecraft encounter.

  9. A Deep Space Optical Communications Demonstration with the Galileo Spacecraft on its Way to Jupiter (abstract)

    NASA Technical Reports Server (NTRS)

    Wilson, K. E.; Lesh, J. R.; Yan, T-Y.

    1993-01-01

    The GOPEX (Galileo Optical communications from an Earth-based transmitter) demonstration was performed from transmitter sites at Table Mountain Observatory, CA and Starfire Optical Range, NM. The experiment was done over an eight day period, December 9 through December 16 as Galileo receded from Earth on its way to Jupiter. At a range of 6 million kilometers (15 times the Earth-Moon distance), the transmission from Table Mountain Observatory eight days after Earth-flyby represents the longest range for laser transmission and detection.

  10. New optical and radio frequency angular tropospheric refraction models for deep space applications

    NASA Technical Reports Server (NTRS)

    Berman, A. L.; Rockwell, S. T.

    1976-01-01

    The development of angular tropospheric refraction models for optical and radio frequency usage is presented. The models are compact analytic functions, finite over the entire domain of elevation angle, and accurate over large ranges of pressure, temperature, and relative humidity. Additionally, FORTRAN subroutines for each of the models are included.

  11. Optical coherence microscopy for deep tissue imaging of the cerebral cortex with intrinsic contrast

    PubMed Central

    Srinivasan, Vivek J.; Radhakrishnan, Harsha; Jiang, James Y.; Barry, Scott; Cable, Alex E.

    2012-01-01

    In vivo optical microscopic imaging techniques have recently emerged as important tools for the study of neurobiological development and pathophysiology. In particular, two-photon microscopy has proved to be a robust and highly flexible method for in vivo imaging in highly scattering tissue. However, two-photon imaging typically requires extrinsic dyes or contrast agents, and imaging depths are limited to a few hundred microns. Here we demonstrate Optical Coherence Microscopy (OCM) for in vivo imaging of neuronal cell bodies and cortical myelination up to depths of ~1.3 mm in the rat neocortex. Imaging does not require the administration of exogenous dyes or contrast agents, and is achieved through intrinsic scattering contrast and image processing alone. Furthermore, using OCM we demonstrate in vivo, quantitative measurements of optical properties (index of refraction and attenuation coefficient) in the cortex, and correlate these properties with laminar cellular architecture determined from the images. Lastly, we show that OCM enables direct visualization of cellular changes during cell depolarization and may therefore provide novel optical markers of cell viability. PMID:22330462

  12. The optical identification content of the Einstein Observatory deep X-ray survey of a region in Pavo

    NASA Technical Reports Server (NTRS)

    Griffiths, R. E.; Murray, S. S.; Giacconi, R.; Bechtold, J.; Murdin, P.; Smith, M.; Macgillivray, H. T.; Ward, M.; Danziger, J.; Lub, J.

    1983-01-01

    Results are presented from the Einstein deep X-ray survey in Pavo, with correlated optical and radio observations of a complete sample of candidate identifications. There are 16 X-ray sources detected with positional accuracy better than 10 arcsec, of which five are identified, with a further seven (and a maximum nine) probable identifications. Of the identified sources, four are QSOs with J-magnitude about 20 (one is an inverted spectrum radio source) and one is associated with extended emission from a pair or cluster of galaxies. Of the probable identifications, one is a galaxy and the rest are a subset of a yellow stellar object population which may also be QSOs. Identifications with QSOs and QSO candidates with J less than 24 account for 60-80 percent of the detected sources.

  13. Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    van Haren, H.; Taupier-Letage, I.; Aguilar, J. A.; Albert, A.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-Cabo, M.; Bouwhuis, M. C.; Brown, A.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Carminati, G.; Carr, J.; Castel, D.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; de Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J.-P.; Escoffier, S.; Fehr, F.; Flaminio, V.; Fratini, K.; Fritsch, U.; Fuda, J.-L.; Giacomelli, G.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; de Jong, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Lahmann, R.; Lamare, P.; Lambard, G.; Larosa, G.; Laschinsky, H.; Lefèvre, D.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Lucarelli, F.; Lyons, K.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Maurin, G.; Mazure, A.; Melissas, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Ostasch, R.; Palioselitis, G.; Păvălaş, G. E.; Payre, P.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Picq, C.; Pillet, R.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Radu, A.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Russo, G. V.; Salesa, F.; Schoeck, F.; Schuller, J.-P.; Shanidze, R.; Simeone, F.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; van Elewyck, V.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.

    2011-08-01

    An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward vertical currents of magnitudes up to 0.03 m s-1 in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These observations coincided with high light levels detected by the telescope, interpreted as increased bioluminescence. During winter 2006 deep dense-water formation occurred in the Ligurian subbasin, thus providing a possible explanation for these observations. However, the 10-20 days quasi-periodic episodes of high levels of acoustic reflection, light and large vertical currents continuing into the summer are not direct evidence of this process. It is hypothesized that the main process allowing for suspended material to be moved vertically later in the year is local advection, linked with topographic boundary current instabilities along the rim of the 'Northern Current'.

  14. Effects of Pressure on Optically Active Deep Levels in Phosphorus Doped ZnSe

    NASA Astrophysics Data System (ADS)

    Weinstein, B. A.; Iota, V.

    1998-03-01

    We report high pressure photoluminescence (PL) and PL-excitation (PLE) studies at 8K of the 'midgap' emission in P-doped ZnSe using a diamond-cell with He medium. The dominant emission at low pressure is due to donor-acceptor-pair (DAP) transitions between shallow donors and deep trigonally relaxed P_Se acceptors.(J. Davies, et al., J. Luminescence 18/19, 322 (1979)) Its PL and PLE peaks shift by 8.2meV/kbar and 5.9meV/kbar, respectively -- Stokes shift decreasing with pressure. At 35kbar a new PL band, shifting to lower energy (-5.4meV/kbar), emerges from above the absorption edge, and concurrently the original DAP PL quenches. This shows that a resonant level, a deep donor or possibly a P_Se antibonding state,(R. Watts, et al., Phys. Rev. B3), 404 (1971) crosses the conduction edge into the gap. A third PL band is seen only with internse UV excitation. It occurs initially as a high energy shoulder of the original DAP peak, but shifts more rapidly upward (9.4meV/kbar) until it crosses the edge and quenches at 40kbar. We discuss candidates for this band, including donor-P_Se complexes, and we compare our results to similar work on the Zn vacancy in ZnSe. (figures)

  15. Optical dimensional metrology at Physikalisch-Technische Bundesanstalt (PTB) on deep sub-wavelength nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Bodermann, B.; Ehret, G.; Endres, J.; Wurm, M.

    2016-06-01

    The dark-field microscopy method with alternating grazing incidence UV illumination (UV-AGID) developed at Physikalisch-Technische Bundesanstalt offers the possibility of measuring individual isolated line structures with linewidths down to the sub-wavelength regime. In contrast, scatterometry is able and already widely used to measure average dimensional parameters of periodic structures down to the deep sub-wavelength regime. Both methods can be used for dimensional measurements of micro- and nanostructures, in particular the critical dimensions (CDs) on wafers or photomasks in the semiconductor industry, complementing each other favourably. Based on numerical simulations, we have investigated the ultimate limits of these two methods in the deep sub-wavelength regime. It has been shown that AGID microscopy in the DUV spectral range is in principle capable of measuring line structures with CDs down to a few 10 nm, depending on the structure material. For scatterometry, no fundamental limit has been observed. In practice, a technical limit due to the limited signal-to-noise ratio is expected for CDs of a few nm in width.

  16. Deep optically thin cirrus clouds in the polar regions. I - Infrared extinction characteristics

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Yoo, Jung-Moon; Dalu, Giuseppe; Fraser, R. S.

    1990-01-01

    The spectral data obtained by the infrared interferometer Spectrometer (IRIS) flown on Nimbus 4 satellite in 1970 indicated the existence of optically thin ice clouds in the upper troposphere that probably extended into lower stratosphere, in the polar regions, during winter and early spring. The spectral features of these clouds differ somewhat from that of the optically thin cirrus clouds in the tropics. From theoretical simulation of the infrared spectra in the 8-25 micron region, it is inferred that these polar clouds have a vertical stratification in particle size, with larger particles (about 12 microns) in the bottom of the cloud and smaller ones (less than 1 micron) aloft. Radiative transfer calculations also suggest that the equivalent ice-water content of these polar clouds is of the order of 1 mg/sq cm.

  17. Design and evaluation of an ultra-slim objective for in-vivo deep optical biopsy

    PubMed Central

    Landau, Sara M.; Liang, Chen; Kester, Robert T.; Tkaczyk, Tomasz S.; Descour, Michael R.

    2010-01-01

    An estimated 1.6 million breast biopsies are performed in the US each year. In order to provide real-time, in-vivo imaging with sub-cellular resolution for optical biopsies, we have designed an ultra-slim objective to fit inside the 1-mm-diameter hypodermic needles currently used for breast biopsies to image tissue stained by the fluorescent probe proflavine. To ensure high-quality imaging performance, experimental tests were performed to characterize fiber bundle’s light-coupling efficiency and simulations were performed to evaluate the impact of candidate lens materials’ autofluorescence. A prototype of NA = 0.4, 250-µm field of view, ultra-slim objective optics was built and tested, yielding diffraction-limited performance and estimated resolution of 0.9 µm. When used in conjunction with a commercial coherent fiber bundle to relay the image formed by the objective, the measured resolution was 2.5 µm. PMID:20389489

  18. A high performance fiber optic pressure penetrator for use in the deep ocean

    NASA Astrophysics Data System (ADS)

    Cowen, S. J.

    1981-02-01

    This report describes results obtained in an FY 80 developmental program carried out at the Naval Ocean System Center, San Diego, under Independent Exploratory Development funding. The objective was to develop a robust, fully-demountable, high pressure penetrator design suitable for coupling light signals transmitted by optical fiber elements in an undersea cable operated at high ambient hydrostatic pressure into an electronics package or manned space. The feasibility of constructing such penetrators utilizing Graded Refractive Index (GRIN) rod lenses as combination pressure barriers and imaging devices has been demonstrated. Prototype realizations have exhibited excellent optical throughput performance and readily survive in excess of 10,000 psi pressure differential as well as tolerating a wide temperature range. The design lends itself to hermetic construction for applications requiring no vapor diffusion over long mission durations. Such devices exhibit excellent potential for satisfying SUBSAFE requirements for manned submarine applications.

  19. Design and implementation of optical imaging and sensor systems for characterization of deep-sea biological camouflage

    NASA Astrophysics Data System (ADS)

    Haag, Justin Mathew

    The visual ecology of deep-sea animals has long been of scientific interest. In the open ocean, where there is no physical structure to hide within or behind, diverse strategies have evolved to solve the problem of camouflage from a potential predator. Simulations of specific predator-prey scenarios have yielded estimates of the range of possible appearances that an animal may exhibit. However, there is a limited amount of quantitative information available related to both animal appearance and the light field at mesopelagic depths (200 m to 1000 m). To mitigate this problem, novel optical instrumentation, taking advantage of recent technological advances, was developed and is described in this dissertation. In the first half of this dissertation, the appearance of mirrored marine animals is quantitatively evaluated. A portable optical imaging scatterometer was developed to measure angular reflectance, described by the bidirectional reflectance distribution function (BRDF), of biological specimens. The instrument allows for BRDF capture from samples of arbitrary size, over a significant fraction of the reflectance hemisphere. Multiple specimens representing two species of marine animals, collected at mesopelagic depths, were characterized using the scatterometer. Low-dimensional parametric models were developed to simplify use of the data sets, and to validate the BRDF method. Results from principal component analysis confirm that BRDF measurements can be used to study intra- and interspecific variability of mirrored marine animal appearance. Collaborative efforts utilizing the BRDF data sets to develop physically-based scattering models are underway. In the second half of this dissertation, another key part of the deep-sea biological camouflage problem is examined. Two underwater radiometers, capable of low-light measurements, were developed to address the lack of available information related to the deep-sea light field. Quantitative comparison of spectral

  20. High Speed Photometry for BUSCA

    NASA Astrophysics Data System (ADS)

    Cordes, O.; Reif, K.

    The camera BUSCA (Bonn University Simultaneous CAmera) is a standard instrument at the 2.2m telescope at Calar Alto Observatory (Spain) since 2001. At the moment some modifications of BUSCA are planned and partially realised. One major goal is the replacement of the old thick CCDs in the blue, yellow-green, and near-infrared channels. The newer CCDs have better cosmetics and performance in sensitivity. The other goal is to replace the old "Heidelberg"-style controller with a newly designed controller with the main focus on high-speed readout and on an advanced windowing mechanism. We present a theoretical analysis of the new controller design and its advantage in high speed photometry of rapidly pulsating stars. As an example PG1605+072 was chosen which was observed with BUSCA before in 2001 and 2002.

  1. The 2060 Chiron: CCD photometry

    NASA Technical Reports Server (NTRS)

    Bus, Schelte J.; Bowell, Edward; Harris, Alan W.

    1987-01-01

    R-band CCD photometry of 2060 was carried out on nine nights in Nov. and Dec. 1986. The rotation period is 5.9181 + or - 0.0003 hr and the peak to peak lightcurve amplitude is 0.088 + or - 0.0003 mag. Photometric parameters are H sub R = 6.24 + or - 0.02 mag and G sub R = + or - 0.15, though formal errors may not be realistic. The lightcurve has two pairs of extrema, but its asymmetry, as evidenced by the presence of significant odd Fourier harmonics, suggests macroscopic surface irregularities and/or the presence of some large scale albedo variegation. The observational rms residual is + or - 0.015 mag. On time scales from minutes to days there is no evidence for nonperiodic (cometary) brightness changes at the level of a few millimagnitudes.

  2. Modulated-alignment dual-axis (MAD) confocal microscopy for deep optical sectioning in tissues

    PubMed Central

    Leigh, Steven Y.; Chen, Ye; Liu, Jonathan T.C.

    2014-01-01

    A strategy is presented to enable optical-sectioning microscopy with improved contrast and imaging depth using low-power (0.5 - 1 mW) diode laser illumination. This technology combines the inherent strengths of focal-modulation microscopy and dual-axis confocal (DAC) microscopy for rejecting out-of-focus and multiply scattered background light in tissues. The DAC architecture is unique in that it utilizes an intersecting pair of illumination and collection beams to improve the spatial-filtering and optical-sectioning performance of confocal microscopy while focal modulation selectively ‘labels’ in-focus signals via amplitude modulation. Simulations indicate that modulating the spatial alignment of dual-axis beams at a frequency f generates signals from the focal volume of the microscope that are modulated at 2f with minimal modulation of background signals, thus providing nearly an order-of-magnitude improvement in optical-sectioning contrast compared to DAC microscopy alone. Experiments show that 2f lock-in detection enhances contrast and imaging depth within scattering phantoms and fresh tissues. PMID:24940534

  3. Reflecting optics in the diverticular eye of a deep-sea barreleye fish (Rhynchohyalus natalensis).

    PubMed

    Partridge, J C; Douglas, R H; Marshall, N J; Chung, W-S; Jordan, T M; Wagner, H-J

    2014-05-07

    We describe the bi-directed eyes of a mesopelagic teleost fish, Rhynchohyalus natalensis, that possesses an extensive lateral diverticulum to each tubular eye. Each diverticulum contains a mirror that focuses light from the ventro-lateral visual field. This species can thereby visualize both downwelling sunlight and bioluminescence over a wide field of view. Modelling shows that the mirror is very likely to be capable of producing a bright, well focused image. After Dolichopteryx longipes, this is only the second description of an eye in a vertebrate having both reflective and refractive optics. Although superficially similar, the optics of the diverticular eyes of these two species of fish differ in some important respects. Firstly, the reflective crystals in the D. longipes mirror are derived from a tapetum within the retinal pigment epithelium, whereas in R. natalensis they develop from the choroidal argentea. Secondly, in D. longipes the angle of the reflective crystals varies depending on their position within the mirror, forming a Fresnel-type reflector, but in R. natalensis the crystals are orientated almost parallel to the mirror's surface and image formation is dependent on the gross morphology of the diverticular mirror. Two remarkably different developmental solutions have thus evolved in these two closely related species of opisthoproctid teleosts to extend the restricted visual field of a tubular eye and provide a well-focused image with reflective optics.

  4. Macular pigment assessment by motion photometry.

    PubMed

    Moreland, J D

    2004-10-15

    A Moreland anomaloscope was modified to measure macular pigment optical density (MPOD) profiles by motion photometry. A grating (spatial frequency 0.38 c deg(-1)), whose alternate bars were filled, respectively, with 460 nm (maximum MP absorption) and 580 nm (zero MP absorption) lights, drifted steadily at 37 degrees s(-1). The subject adjusted the 580 nm radiance to minimise perceived motion (equiluminance between 460 and 580 nm). Five or more settings were made for two foveal fields (0.9 degrees and 2.2 degrees diameter) and 11 extrafoveal annular fields (0.8 degrees -7.5 degrees eccentricity). Twenty subjects made measurements for both eyes: some with replications. MPOD profiles varied in scale (0.18-0.75 for the 0.9 degrees foveal field) and in shape. A mean profile was derived. Foveal data were optimally aligned with annular data in that profile when plotted at 0.71 of the foveal field radius. Factors that limit precision were identified, such as fixation errors foveally and Troxler's effect parafoveally.

  5. Long term monitoring of the optical background in the Capo Passero deep-sea site with the NEMO tower prototype

    NASA Astrophysics Data System (ADS)

    Adrián-Martínez, S.; Aiello, S.; Ameli, F.; Anghinolfi, M.; Ardid, M.; Barbarino, G.; Barbarito, E.; Barbato, F. C. T.; Beverini, N.; Biagi, S.; Biagioni, A.; Bouhadef, B.; Bozza, C.; Cacopardo, G.; Calamai, M.; Calì, C.; Calvo, D.; Capone, A.; Caruso, F.; Ceres, A.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coniglione, R.; Costa, M.; Cuttone, G.; D'Amato, C.; D'Amico, A.; De Bonis, G.; De Luca, V.; Deniskina, N.; De Rosa, G.; di Capua, F.; Distefano, C.; Enzenhöfer, A.; Fermani, P.; Ferrara, G.; Flaminio, V.; Fusco, L. A.; Garufi, F.; Giordano, V.; Gmerk, A.; Grasso, R.; Grella, G.; Hugon, C.; Imbesi, M.; Kulikovskiy, V.; Lahmann, R.; Larosa, G.; Lattuada, D.; Leismüller, K. P.; Leonora, E.; Litrico, P.; Llorens Alvarez, C. D.; Lonardo, A.; Longhitano, F.; Lo Presti, D.; Maccioni, E.; Margiotta, A.; Marinelli, A.; Martini, A.; Masullo, R.; Migliozzi, P.; Migneco, E.; Miraglia, A.; Mollo, C. M.; Mongelli, M.; Morganti, M.; Musico, P.; Musumeci, M.; Nicolau, C. A.; Orlando, A.; Orzelli, A.; Papaleo, R.; Pellegrino, C.; Pellegriti, M. G.; Perrina, C.; Piattelli, P.; Pugliatti, C.; Pulvirenti, S.; Raffaelli, F.; Randazzo, N.; Real, D.; Riccobene, G.; Rovelli, A.; Saldaña, M.; Sanguineti, M.; Sapienza, P.; Sciacca, V.; Sgura, I.; Simeone, F.; Sipala, V.; Speziale, F.; Spitaleri, A.; Spurio, M.; Stellacci, S. M.; Taiuti, M.; Terreni, G.; Trasatti, L.; Trovato, A.; Ventura, C.; Vicini, P.; Viola, S.; Vivolo, D.

    2016-02-01

    The NEMO Phase-2 tower is the first detector which was operated underwater for more than 1 year at the "record" depth of 3500 m. It was designed and built within the framework of the NEMO (NEutrino Mediterranean Observatory) project. The 380 m high tower was successfully installed in March 2013 80 km offshore Capo Passero (Italy). This is the first prototype operated on the site where the Italian node of the KM3NeT neutrino telescope will be built. The installation and operation of the NEMO Phase-2 tower has proven the functionality of the infrastructure and the operability at 3500 m depth. A more than 1 year long monitoring of the deep water characteristics of the site has been also provided. In this paper the infrastructure and the tower structure and instrumentation are described. The results of long term optical background measurements are presented. The rates show stable and low baseline values, compatible with the contribution of ^{40}K light emission, with a small percentage of light bursts due to bioluminescence. All these features confirm the stability and good optical properties of the site.

  6. A deep search for the host galaxies of gamma-ray bursts with no detected optical afterglow

    NASA Astrophysics Data System (ADS)

    Rossi, A.; Klose, S.; Ferrero, P.; Greiner, J.; Arnold, L. A.; Gonsalves, E.; Hartmann, D. H.; Updike, A. C.; Kann, D. A.; Krühler, T.; Palazzi, E.; Savaglio, S.; Schulze, S.; Afonso, P. M. J.; Amati, L.; Castro-Tirado, A. J.; Clemens, C.; Filgas, R.; Gorosabel, J.; Hunt, L. K.; Küpcü Yoldaş, A.; Masetti, N.; Nardini, M.; Nicuesa Guelbenzu, A.; Olivares, F. E.; Pian, E.; Rau, A.; Schady, P.; Schmidl, S.; Yoldaş, A.; de Ugarte Postigo, A.

    2012-09-01

    Context. Gamma-ray bursts (GRBs) can provide information about star formation at high redshifts. Even in the absence of a bright optical/near-infrared/radio afterglow, the high detection rate of X-ray afterglows by Swift/XRT and its localization precision of 2-3 arcsec facilitates the identification and the study of GRB host galaxies. Aims: We focus on the search for the host galaxies of 17 bursts with arcsec-sized XRT error circles but no detected long-wavelength afterglow, in spite of their deep and rapid follow-up observations. Three of these events can also be classified as truly dark bursts, i.e., the observed upper limit on the optical flux of the afterglow was less than expected based on the measured X-ray flux. Our goals are to identify the GRB host galaxy candidates and characterize their phenomenological parameters. Methods: Our study is based on deep RC and Ks-band observations performed with FORS1, FORS2, VIMOS, ISAAC, and HAWK-I at the ESO/VLT, partly supported by observations with the seven-channel imager GROND at the 2.2-m telescope on La Silla, and supplemented by observations with NEWFIRM at the 4-m telescope on Kitt Peak. To be conservative, we searched for host galaxy candidates within an area of twice the radius of each associated 90% c.l. Swift/XRT error circle. Results: For 15 of the 17 bursts, we find at least one galaxy within the searching area, and in the remaining two cases only a deep upper limit to RC and Ks can be provided. In seven cases, we discover extremely red objects in the error circles, at least four of which might be dust-enshrouded galaxies. The most remarkable case is the host of GRB 080207, which has a color of (RC - Ks)AB ~ 4.7 mag, and is one of the reddest galaxies ever associated with a GRB. As a by-product of our study we identify the optical afterglow of GRB 070517. Conclusions: Only a minority of optically dim afterglows are due to Lyman dropout (≲ 1/3). Extinction by dust in the host galaxies might explain all

  7. Deep-ultraviolet antireflective coating with improved conformality, optical density, and etch rate

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Meador, James D.; Xu, Gu; Suzuki, Hitoshi; Sone, Yasuhisa; Krishnamurthy, Vandana N.; Claypool, James B.; Lamb, James E., III

    1998-06-01

    A new bottom antireflective coating (BARC) for 248 nm lithography is described. The new coating has an optical density of approximately 10/micrometers (k equals 0.41 and n equals 1.482) and plasma etches at rates higher than that of DUV resists depending on the etch conditions. Coating conformality is superior to older generation BARCs, also contributing to improved etch dynamics. Excellent 0.25 micrometers features have been obtained with ESCAP, Acetal and t-BOC type photoresists. The new BARC is spin coated from safe solvents and is spin bowl compatible with EBR and photoresist solvents.

  8. DEEP-South: Preliminary Lightcurves of Potentially Hazardous Asteroids from the First Year Operation

    NASA Astrophysics Data System (ADS)

    Moon, Hong-Kyu; Kim, Myung-Jin; Choi, Young-Jun; Yim, Hong-Suh; Park, Jintae; Roh, Dong-Goo; Lee, Hee-Jae; Oh, Young-Seok; Bae, Young-Ho

    2016-10-01

    Deep Ecliptic Patrol of the Southern Sky (DEEP-South) observation is being made during the off-season for exoplanet search. It started in October 2015, using Korea Microlensing Telescope Network (KMTNet), a network of three identical telescopes with 1.6 m aperture equipped with 18K × 18K CCDs located in Chile (CTIO), South Africa (SAAO), and Australia (SSO). The combination of KMTNet's prime focus optics and the 340 million pixel CCD provides four square degree field of view with 0.4 arcsec/pixel plate scale.Most of the allocated time for DEEP-South is devoted to targeted photometry of PHAs and NEAs to increase the number of those objects with known physical properties. It is efficiently achieved by multiband, time series photometry. This Opposition Census (OC) mode targets objects near their opposition, with km-sized PHAs in early stage and goes down to sub-km objects. Continuous monitoring of the sky with KMTNEt is optimized for spin characterization of various kinds of asteroids, including binaries, slow/fast- and non-principal axis- rotators, and hence expected to facilitate the debiasing of previously reported lightcurve observations. We present the preliminary lightcurves of PHAs from year one of the DEEP-South Project.

  9. Photometry of the cometary atmosphere: A review

    NASA Technical Reports Server (NTRS)

    Vanysek, V.

    1976-01-01

    Photometry and polarimetry of the cometary heads one of the most important sources of information about the physical processes in comets is reviewed. Methods of inspection discussed include: narrow band photometry, wide band photometry, color photography, tilting filter techniques, and photoelectric spectrum scanning. Results of photoelectric observations of comets are described including photoelectric and infrared measurements of comet Kohoutek. Photometric profiles of the coma in monochromatic light are used to determine the lifetime of the parent molecules for the observed radicals, CN and C2.

  10. A Phosphorus Phthalocyanine Formulation with Intense Absorbance at 1000 nm for Deep Optical Imaging

    PubMed Central

    Zhou, Yang; Wang, Depeng; Zhang, Yumiao; Chitgupi, Upendra; Geng, Jumin; Wang, Yuehang; Zhang, Yuzhen; Cook, Timothy R.; Xia, Jun; Lovell, Jonathan F.

    2016-01-01

    Although photoacoustic computed tomography (PACT) operates with high spatial resolution in biological tissues deeper than other optical modalities, light scattering is a limiting factor. The use of longer near infrared wavelengths reduces scattering. Recently, the rational design of a stable phosphorus phthalocyanine (P-Pc) with a long wavelength absorption band beyond 1000 nm has been reported. Here, we show that when dissolved in liquid surfactants, P-Pc can give rise to formulations with absorbance of greater than 1000 (calculated for a 1 cm path length) at wavelengths beyond 1000 nm. Using the broadly accessible Nd:YAG pulse laser emission output of 1064 nm, P-Pc could be imaged through 11.6 cm of chicken breast with PACT. P-Pc accumulated passively in tumors following intravenous injection in mice as observed by PACT. Following oral administration, P-Pc passed through the intestine harmlessly, and PACT could be used to non-invasively observe intestine function. When the contrast agent placed under the arm of a healthy adult human, a PACT transducer on the top of the arm could readily detect P-Pc through the entire 5 cm limb. Thus, the approach of using contrast media with extreme absorption at 1064 nm readily enables high quality optical imaging in vitro and in vivo in humans at exceptional depths. PMID:27022416

  11. The VVDS-VLA deep field. II. Optical and near infrared identifications of VLA S1.4 GHz > 80 μ Jy sources in the VIMOS VLT deep survey VVDS-02h field

    NASA Astrophysics Data System (ADS)

    Ciliegi, P.; Zamorani, G.; Bondi, M.; Pozzetti, L.; Bolzonella, M.; Gregorini, L.; Garilli, B.; Iovino, A.; McCracken, H. J.; Mellier, Y.; Radovich, M.; de Ruiter, H. R.; Parma, P.; Bottini, D.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bardelli, S.; Cappi, A.; Charlot, S.; Contini, T.; Foucaud, S.; Franzetti, P.; Guzzo, L.; Ilbert, O.; Marano, B.; Marinoni, C.; Mathez, G.; Mazure, A.; Meneux, B.; Merighi, R.; Merluzzi, P.; Paltani, S.; Pollo, A.; Zucca, E.; Bongiorno, A.; Busarello, G.; Gavignaud, I.; Pellò, R.; Ripepi, V.; Rizzo, D.

    2005-10-01

    In this paper we present the optical and near-infrared identifications of the 1054 radio sources detected in the 20 cm deep radio survey down to a 5σ flux limit of ~80 μJy obtained with the VLA in the VIMOS VLT Deep Survey VVDS-02h deep field. Using U,B,V,R,I and K data, with limiting magnitudes of UAB˜25.4, BAB˜26.5, VAB˜26.2, RAB˜25.9 IAB˜25.0, JAB˜24.2, KAB˜23.9 (50% completeness) we identified 718 radio sources (~74% of the whole sample). The photometric redshift analysis shows that, in each magnitude bin, the radio sample has a higher median photometric redshift than the whole optical sample, while the median (V-I)AB color of the radio sources is redder than the median color of the whole optical sample. These results suggest that radio detection is preferentially selecting galaxies with higher intrinsic optical luminosity. From the analysis of the optical properties of the radio sources as function of the radio flux, we found that while about 35% of the radio sources are optically unidentified in the higher radio flux bin (S> 1.0 mJy), the percentage of unidentified sources decreases to about 25% in the faintest bins (S< 0.5 mJy). The median IAB magnitude for the total sample of radio sources, i.e. including also the unidentified ones, is brighter in the faintest radio bins than in the bin with higher radio flux. This suggests that most of the faintest radio sources are likely to be associated to relatively lower radio luminosity objects at relatively modest redshift, rather than radio-powerful, AGN type objects at high redshift. Using a classification in early-type and late-type galaxies based on the (B-I)AB color and the photometric redshift, we found that the majority of the radio sources below ~0.15 mJy are indeed late-type star forming galaxies. Finally, the radio sources without optical counterpart in our deep imaging have a median radio flux of 0.15 mJy, equal to that of identified sources. Given the very faint optical limits, these

  12. Spectroscopy and photometry for low-mass stars in Praesepe

    NASA Technical Reports Server (NTRS)

    Williams, Scott D.; Stauffer, John R.; Prosser, Charles F.; Herter, Terry

    1994-01-01

    We have obtained spectral types, H alpha equivalent widths, and optical photometry for a small sample of late K and M dwarf candidate members of the Praesepe open cluster. At least for the small sample of stars we have observed, all of the Paesepe members later than M2 have H alpha in emission. The chromospheric activity of the Praesepe satrs is essentially the same as that for Hyades members of the same mass, as expected since the two clusters are thought to be the same age.

  13. Long-term photometry of WX Arietis: evidence for eclipses and dips

    NASA Astrophysics Data System (ADS)

    Rodríguez-Gil, P.; Casares, J.; Dhillon, V. S.; Martínez-Pais, I. G.

    2000-03-01

    We present R-band photometry of the SW Sex-type cataclysmic variable WX Arietis made in October 1995 and August 1998-February 1999. Contrary to previous results, we find that WX Ari is an eclipsing system with an orbital inclination of i =~ 72o. The R-band light curves display highly variable, shallow eclipses ~ 0.15-mag deep and =~ 40 min long. The observed eclipse depth suggests a partial eclipse of the accretion disc. The light curves also show a wide dip in brightness centred at orbital phase varphi ~ 0.75 and a hump close to the opposite phase at varphi ~ 0.2. The observed dip may be explained by the probable vertical thickening of the outer rim of the accretion disc downstream from the bright spot. We also demonstrate that the disc brightness in all SW Sex systems is nearly the same. This implies that the orbital inclination of these systems is only a function of eclipse depth. Based on observations made with the Optical Ground Station (OGS) and the IAC--80 telescopes, operated on the island of Tenerife by the European Space Agency (ESA) and the Ins\\-ti\\-tu\\-to de Astrof\\'\\i sica de Canarias (IAC), respectively, at the Spanish Observatorio del Teide and with the Jacobus Kapteyn Telescope (JKT), operated on the island of La Palma by PPARC at the Spanish Observatorio del Roque de los Muchachos.

  14. Permanent optical doping of amorphous metal oxide semiconductors by deep ultraviolet irradiation at room temperature

    SciTech Connect

    Seo, Hyungtak; Cho, Young-Je; Bobade, Santosh M.; Park, Kyoung-Youn; Choi, Duck-Kyun; Kim, Jinwoo; Lee, Jaegab

    2010-05-31

    We report an investigation of two photon ultraviolet (UV) irradiation induced permanent n-type doping of amorphous InGaZnO (a-IGZO) at room temperature. The photoinduced excess electrons were donated to change the Fermi-level to a conduction band edge under the UV irradiation, owing to the hole scavenging process at the oxide interface. The use of optically n-doped a-IGZO channel increased the carrier density to approx10{sup 18} cm{sup -3} from the background level of 10{sup 16} cm{sup -3}, as well as the comprehensive enhancement upon UV irradiation of a-IGZO thin film transistor parameters, such as an on-off current ratio at approx10{sup 8} and field-effect mobility at 22.7 cm{sup 2}/V s.

  15. A multi-wavelength study of the IRAS Deep Survey galaxy sample. I. Optical observations. The redshift distribution

    NASA Astrophysics Data System (ADS)

    Della Valle, A.; Mazzei, P.; Bettoni, D.; Aussel, H.; de Zotti, G.

    2006-08-01

    Context: The IRAS Deep Survey (IDS) of the North Ecliptic Pole region remains one of the deepest complete far-infrared-selected galaxy samples available. ISOCAM observations in the LW3 filter (12-18 μm) of 3.2 arcmin × 3.2 arcmin fields centered on the nominal positions of 94 out of the 98 IDS sources yielding 116 ISOCAM detections. The resulting sample has allowed us to assess the source reliability, identify confusion effects, and pinpoint optical counterparts. Aims: To fully exploit the potential of this sample for investigating galaxy evolution, we carried out optical observations of candidate identifications to 100 out of the 116 ISOCAM sources. Methods: Optical imaging was acquired for 88 galaxies in 54 IDS fields: 44 galaxies were imaged in both the B- and the R-band, 33 only in the R-band, and 11 only in the B-band. These observations aimed at extending the MIR/FIR spectral energy distribution to the optical region and achieving morphological information. In addition, spectra were obtained for 65 IDS fields, 20 of which had not been observed before. Redshifts were measured for the 85 galaxies found within the positional error circles of 77 ISOCAM sources detected in those IDS fields. Results: These observations allowed us to acquire spectroscopic redshifts of all counterparts that until now lacked them, so that, in combination with the results by Ashby et al. (1996), we now have redshifts for all IDS/ISOCAM galaxies in the field and, in particular, for the complete sub-sample of IDS galaxies defined by Mazzei et al. (2001). Conclusions: In several cases we find evidence of multiple galaxies with very close redshifts within the error circles around ISOCAM positions, hinting at an important role for interactions in triggering the star formation activity. Although the z distribution of the complete sub-sample has a tail extending up to z≃ 0.37, our results are inconsistent with the extreme cosmological evolution advocated by some models.

  16. WFPC2 Stellar Photometry with HSTphot

    NASA Technical Reports Server (NTRS)

    Dolphin, Andrew E.

    2000-01-01

    HSTphot, a photometry package designed to handle the undersampled PSFs found in WFPC2 images, is introduced and described, as well as some of the considerations that have to be made in order to obtain accurate PSF-fitting stellar photometry with WFPC2 data. Tests of HSTphot's internal reliability are made using multiple observations of the same field, and tests of external reliability are made by comparing with DoPHOT reductions of the same data. Subject headz'ngs: techniques: photometric

  17. Meteor44 Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

    2004-01-01

    Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image's plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length 'streak' meteor photometry and two-station track determination. Meteor44 has been used to analyze data from the 2001, 2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

  18. First photometry results from Gaia

    NASA Astrophysics Data System (ADS)

    Brown, Anthony

    2015-08-01

    An overview of the Gaia Photometric Processing is presented. The Gaia photometry consists of the white light (330-1050 nm) G-band, and low resolution spectrophotometry realized by two prisms dispersing all the light entering the field of view. One disperser - called BP for Blue Photometer- operates in the wavelength range 330-680 nm; the other - called RP for Red Photometer - covers the wavelength range 640-1050 nm. The light collected by BP and RP can also be integrated into two broad bands, G_BP and G_RP.This photometric data reduction is based on the overall principle of a self-calibrating system improved by iteration. The input data includes flux (G, G_BP, G_RP) and the low-resolution spectral data. The calibration models and algorithms used are described. Initial validation results are shown which indicate the photometric quality of the preliminary calibrated data. Expectations for the quality of the photometric data to be included in the first public data release (mid-2016) are discussed.

  19. Multicolor Photometry for Mode Identification

    NASA Astrophysics Data System (ADS)

    Reed, M. D.

    The goal of asteroseismology is to discern the physical conditions of stars by comparing observed pulsations with models. To obtain this goal, the observed pulsation periods and the spherical harmonics (n, l, and m) need to match the theoretical model. Typically the most difficult part in this process is the identification of the pulsation modes in the observations. Multicolour photometry is one method that has proven useful for identifying pulsation modes. By observing stars through various wavebands, and comparing the amplitudes and phases, it is possible to determine the spherical harmonics. This contribution will emphasize the work of Watson (1988), which has since been applied to many different types of variable stars including δ Scuti (Garrido et al., 1990), γ Doradus (Breger et al., 1997), β Cepheid (Cugier et al., 1994), and EC 14026 (Koen, 1998) stars. I will also discuss the technique of summing spectra (especially UV) into various wavebands which are then used to identify modes as pioneered by Robinson, Kepler, and Nather (1982) and applied to white dwarf stars (Kepler et al., 2000).

  20. Daytime Use of Astronomical Telescopes for Deep-Space Optical Links

    NASA Technical Reports Server (NTRS)

    Roberts, W. Thomas; Ortiz, Gerard G.; Boyd, Tim A.

    2006-01-01

    Tests at the 200-inch Hale Telescope on Palomar Mountain have demonstrated this telescope's ability to withstand considerable thermal stress, and subsequently produce remarkably unaffected results. During the day of June 29,2005, the Hale telescope dome was left open, and the telescope was exposed to outside air and direct sunlight for 8 hours. During this time, portions of the telescope structure in the telescope's optical path experienced temperature elevations of 30 C, while the primary mirror experienced unprecedented heating of over 3 C. The telescope's measured blind pointing accuracy after this exposure was not noticeably degraded from the measurements taken before exposure. More remarkably, the telescope consistently produced stellar images which were significantly better after exposure of the telescope (1.2 arcsec) than before (1.6 arcsec), even though the conditions of observation were similar. This data is the first step in co-opting astronomical telescopes for daytime use as astronomical receivers, and supports the contention that deleterious effects from daytime exposure of the telescope can be held to an acceptable level for interleaved communications and astronomy.

  1. Deep feature learning for automatic tissue classification of coronary artery using optical coherence tomography.

    PubMed

    Abdolmanafi, Atefeh; Duong, Luc; Dahdah, Nagib; Cheriet, Farida

    2017-02-01

    Kawasaki disease (KD) is an acute childhood disease complicated by coronary artery aneurysms, intima thickening, thrombi, stenosis, lamellar calcifications, and disappearance of the media border. Automatic classification of the coronary artery layers (intima, media, and scar features) is important for analyzing optical coherence tomography (OCT) images recorded in pediatric patients. OCT has been known as an intracoronary imaging modality using near-infrared light which has recently been used to image the inner coronary artery tissues of pediatric patients, providing high spatial resolution (ranging from 10 to 20 μm). This study aims to develop a robust and fully automated tissue classification method by using the convolutional neural networks (CNNs) as feature extractor and comparing the predictions of three state-of-the-art classifiers, CNN, random forest (RF), and support vector machine (SVM). The results show the robustness of CNN as the feature extractor and random forest as the classifier with classification rate up to 96%, especially to characterize the second layer of coronary arteries (media), which is a very thin layer and it is challenging to be recognized and specified from other tissues.

  2. Deep feature learning for automatic tissue classification of coronary artery using optical coherence tomography

    PubMed Central

    Abdolmanafi, Atefeh; Duong, Luc; Dahdah, Nagib; Cheriet, Farida

    2017-01-01

    Kawasaki disease (KD) is an acute childhood disease complicated by coronary artery aneurysms, intima thickening, thrombi, stenosis, lamellar calcifications, and disappearance of the media border. Automatic classification of the coronary artery layers (intima, media, and scar features) is important for analyzing optical coherence tomography (OCT) images recorded in pediatric patients. OCT has been known as an intracoronary imaging modality using near-infrared light which has recently been used to image the inner coronary artery tissues of pediatric patients, providing high spatial resolution (ranging from 10 to 20 μm). This study aims to develop a robust and fully automated tissue classification method by using the convolutional neural networks (CNNs) as feature extractor and comparing the predictions of three state-of-the-art classifiers, CNN, random forest (RF), and support vector machine (SVM). The results show the robustness of CNN as the feature extractor and random forest as the classifier with classification rate up to 96%, especially to characterize the second layer of coronary arteries (media), which is a very thin layer and it is challenging to be recognized and specified from other tissues. PMID:28271012

  3. Improving Kepler Pipeline Sensitivity with Pixel Response Function Photometry.

    NASA Astrophysics Data System (ADS)

    Morris, Robert L.; Bryson, Steve; Jenkins, Jon Michael; Smith, Jeffrey C

    2014-06-01

    We present the results of our investigation into the feasibility and expected benefits of implementing PRF-fitting photometry in the Kepler Science Processing Pipeline. The Kepler Pixel Response Function (PRF) describes the expected system response to a point source at infinity and includes the effects of the optical point spread function, the CCD detector responsivity function, and spacecraft pointing jitter. Planet detection in the Kepler pipeline is currently based on simple aperture photometry (SAP), which is most effective when applied to uncrowded bright stars. Its effectiveness diminishes rapidly as target brightness decreases relative to the effects of noise sources such as detector electronics, background stars, and image motion. In contrast, PRF photometry is based on fitting an explicit model of image formation to the data and naturally accounts for image motion and contributions of background stars. The key to obtaining high-quality photometry from PRF fitting is a high-quality model of the system's PRF, while the key to efficiently processing the large number of Kepler targets is an accurate catalog and accurate mapping of celestial coordinates onto the focal plane. If the CCD coordinates of stellar centroids are known a priori then the problem of PRF fitting becomes linear. A model of the Kepler PRF was constructed at the time of spacecraft commissioning by fitting piecewise polynomial surfaces to data from dithered full frame images. While this model accurately captured the initial state of the system, the PRF has evolved dynamically since then and has been seen to deviate significantly from the initial (static) model. We construct a dynamic PRF model which is then used to recover photometry for all targets of interest. Both simulation tests and results from Kepler flight data demonstrate the effectiveness of our approach. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science

  4. Adaptive Optics Views of the Hubble Deep Fields Final report on LLNL LDRD Project 03-ERD-002

    SciTech Connect

    Max, C E; Gavel, D; Pennington, D; Gibbard, S; van Dam, M; Larkin, J; Koo, D; Raschke, L; Melbourne, J

    2007-02-17

    We used laser guide star adaptive optics at the Lick and Keck Observatories to study active galactic nuclei and galaxies, with emphasis on those in the early Universe. The goals were to observe large galaxies like our own Milky Way in the process of their initial assembly from sub-components, to identify central active galactic nuclei due to accreting black holes in galaxy cores, and to measure rates of star formation and evolution in galaxies. In the distant universe our focus was on the GOODS and GEMS fields (regions in the Northern and Southern sky that include the Hubble Deep Fields) as well as the Extended Groth Strip and COSMOS fields. Each of these parts of the sky has been intensively studied at multiple wavelengths by the Hubble Space Telescope, the Chandra X-Ray Observatory, the XMM Space Telescope, the Spitzer Space Telescope, and several ground-based telescopes including the Very Large Array radio interferometer, in order to gain an unbiased view of a significant statistical sample of galaxies in the early universe.

  5. Deep SDSS optical spectroscopy of distant halo stars. II. Iron, calcium, and magnesium abundances

    NASA Astrophysics Data System (ADS)

    Fernández-Alvar, E.; Allende Prieto, C.; Schlesinger, K. J.; Beers, T. C.; Robin, A. C.; Schneider, D. P.; Lee, Y. S.; Bizyaev, D.; Ebelke, G.; Malanushenko, E.; Malanushenko, V.; Oravetz, D.; Pan, K.; Simmons, A.

    2015-05-01

    Aims: We analyze a sample of 3944 low-resolution (R ~ 2000) optical spectra from the Sloan Digital Sky Survey (SDSS), focusing on stars with effective temperatures 5800 ≤ Teff ≤ 6300 K, and distances from the Milky Way plane in excess of 5 kpc, and determine their abundances of Fe, Ca, and Mg. Methods: We followed the same methodology as in the previous paper in this series, deriving atmospheric parameters by χ2 minimization, but this time we obtained the abundances of individual elements by fitting their associated spectral lines. Distances were calculated from absolute magnitudes obtained by a statistical comparison of our stellar parameters with stellar-evolution models. Results: The observations reveal a decrease in the abundances of iron, calcium, and magnesium at large distances from the Galactic center. The median abundances for the halo stars analyzed are fairly constant up to a Galactocentric distance r ~ 20 kpc, rapidly decrease between r ~ 20 and r ~ 40 kpc, and flatten out to significantly lower values at larger distances, consistent with previous studies. In addition, we examine [Ca/Fe] and [Mg/Fe] as a function of [Fe/H] and Galactocentric distance. Our results show that the most distant parts of the halo show a steeper variation of [Ca/Fe] and [Mg/Fe] with iron. We found that at the range -1.6 < [Fe/H] < -0.4, [Ca/Fe] decreases with distance, in agreement with earlier results based on local stars. However, the opposite trend is apparent for [Mg/Fe]. Our conclusion that the outer regions of the halo are more metal-poor than the inner regions, based on in situ observations of distant stars, agrees with recent results based on inferences from the kinematics of more local stars, and with predictions of recent galaxy formation simulations for galaxies similar to the Milky Way. Table 1 and beginning of Tables 2 and 3 are available in electronic form at http://www.aanda.orgFull Tables 2 and 3 are only available at the CDS via anonymous ftp to http

  6. Distant Comets Photometry and Dust Modeling

    NASA Astrophysics Data System (ADS)

    Pittichova, Jana; Meech, K. J.; Bar-Nun, A.; Notesco, G.

    2008-09-01

    Several comets have been observed to develop coma on their in-bound leg at heliocentric distances from 5.84 to 11.49 AU. We will present the observational evidence for their activity and propose an explanation based on experiments carried out on amorphous, gas-laden ice samples that are 0.1 to 100 microns thick and formed by flowing water vapor and CO onto a cold surface. The considerable gas emission occurs when the amorphous ice anneals before 135K, where it transforms into a crystalline structure. This activity was found experimentally to be associated with gas release during annealing of the gas-laden amorphous ice. We observed and measured optical CCD photometry for two short-period and five long-period, dynamically new comets, that have enter the inner solar system directly from the Oort cloud for the first time. All of these comets have been observed pre-perihelion. Observations were done with the University of Hawaii 2.2-m telescope on Mauna Kea with the Tektronix 2x2K CCD camera through the Kron-Cousins B, V, R, I filter system. In order to observationally distinguish the physical causes of activity, not only is it important to observe comets at large heliocentric distances, but also those that are dynamically new and on the in-bound leg of their orbits at distances beyond where the amorphous to crystalline ice phase transition can occur. This research includes observations of the level of nucleus activity as a function of distance. We also would like to present Finson-Probstein (FP) dust modeling investigation on select comets. From the FP dust modeling of a cometary tail we can determine three basic parameters: the dust production rate, the particle distribution, and the emission velocity of the grains.

  7. The Araucaria Project. A Distance Determination to the Local Group Spiral M33 from Near-infrared Photometry of Cepheid Variables

    NASA Astrophysics Data System (ADS)

    Gieren, Wolfgang; Górski, Marek; Pietrzyński, Grzegorz; Konorski, Piotr; Suchomska, Ksenia; Graczyk, Dariusz; Pilecki, Bogumil; Bresolin, Fabio; Kudritzki, Rolf-Peter; Storm, Jesper; Karczmarek, Paulina; Gallenne, Alexandre; Calderón, Paula; Geisler, Doug

    2013-08-01

    Motivated by an amazing range of reported distances to the nearby Local Group spiral galaxy M33, we have obtained deep near-infrared photometry for 26 long-period Cepheids in this galaxy with the ESO Very Large Telescope. From the data, we constructed period-luminosity relations in the J and K bands which together with previous optical VI photometry for the Cepheids by Macri et al. were used to determine the true distance modulus of M33, and the mean reddening affecting the Cepheid sample with the multiwavelength fit method developed in the Araucaria Project. We find a true distance modulus of 24.62 for M33, with a total uncertainty of ±0.07 mag which is dominated by the uncertainty on the photometric zero points in our photometry. The reddening is determined as E(B - V) = 0.19 ± 0.02, in agreement with the value used by the Hubble Space Telescope Key Project of Freedman et al. but in some discrepancy with other recent determinations based on blue supergiant spectroscopy and an O-type eclipsing binary which yielded lower reddening values. Our derived M33 distance modulus is extremely insensitive to the adopted reddening law. We show that the possible effects of metallicity and crowding on our present distance determination are both at the 1%-2% level and therefore minor contributors to the total uncertainty of our distance result for M33. Based on observations obtained with the ESO VLT for program 382.D-0469(A).

  8. Deep tissue optical imaging of upconverting nanoparticles enabled by exploiting higher intrinsic quantum yield through use of millisecond single pulse excitation with high peak power.

    PubMed

    Liu, Haichun; Xu, Can T; Dumlupinar, Gökhan; Jensen, Ole B; Andersen, Peter E; Andersson-Engels, Stefan

    2013-10-21

    We have accomplished deep tissue optical imaging of upconverting nanoparticles at 800 nm, using millisecond single pulse excitation with high peak power. This is achieved by carefully choosing the pulse parameters, derived from time-resolved rate-equation analysis, which result in higher intrinsic quantum yield that is utilized by upconverting nanoparticles for generating this near infrared upconversion emission. The pulsed excitation approach thus promises previously unreachable imaging depths and shorter data acquisition times compared with continuous wave excitation, while simultaneously keeping the possible thermal side-effects of the excitation light moderate. These key results facilitate means to break through the general shallow depth limit of upconverting-nanoparticle-based fluorescence techniques, necessary for a range of biomedical applications, including diffuse optical imaging, photodynamic therapy and remote activation of biomolecules in deep tissues.

  9. Towards photometry pipeline of the Indonesian space surveillance system

    NASA Astrophysics Data System (ADS)

    Priyatikanto, Rhorom; Religia, Bahar; Rachman, Abdul; Dani, Tiar

    2015-09-01

    Optical observation through sub-meter telescope equipped with CCD camera becomes alternative method for increasing orbital debris detection and surveillance. This observational mode is expected to eye medium-sized objects in higher orbits (e.g. MEO, GTO, GSO & GEO), beyond the reach of usual radar system. However, such observation of fast moving objects demands special treatment and analysis technique. In this study, we performed photometric analysis of the satellite track images photographed using rehabilitated Schmidt Bima Sakti telescope in Bosscha Observatory. The Hough transformation was implemented to automatically detect linear streak from the images. From this analysis and comparison to USSPACECOM catalog, two satellites were identified and associated with inactive Thuraya-3 satellite and Satcom-3 debris which are located at geostationary orbit. Further aperture photometry analysis revealed the periodicity of tumbling Satcom-3 debris. In the near future, it is not impossible to apply similar scheme to establish an analysis pipeline for optical space surveillance system hosted in Indonesia.

  10. Deep-ultraviolet nonlinear optical materials: Na2Be4B4O11 and LiNa5Be12B12O33.

    PubMed

    Huang, Hongwei; Liu, Lijuan; Jin, Shifeng; Yao, Wenjiao; Zhang, Yihe; Chen, Chuangtian

    2013-12-11

    Deep-UV coherent light generated by nonlinear optical (NLO) materials possesses highly important applications in photonic technologies. Beryllium borates comprising anionic planar layers have been shown to be the most promising deep UV NLO materials. Here, two novel NLO beryllium borates Na2Be4B4O11 and LiNa5Be12B12O33 have been developed through cationic structural engineering. The most closely arranged [Be2BO5]∞ planar layers, connected by the flexible [B2O5] groups, have been found in their structures. This structural regulation strategy successfully resulted in the largest second harmonic generation (SHG) effects in the layered beryllium borates, which is ~1.3 and 1.4 times that of KDP for Na2Be4B4O11 and LiNa5Be12B12O33, respectively. The deep-UV optical transmittance spectra based on single crystals indicated their short-wavelength cut-offs are down to ~170 nm. These results demonstrated that Na2Be4B4O11 and LiNa5Be12B12O33 possess very promising application as deep-UV NLO crystals.

  11. Design and Synthesis of the Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material Ba₃(ZnB₅O₁₀)PO₄.

    PubMed

    Yu, Hongwei; Zhang, Weiguo; Young, Joshua; Rondinelli, James M; Halasyamani, P Shiv

    2015-12-02

    Access to the elusive deep-ultraviolet by direct second harmonic generation (SHG) enabled by a new beryllium-free zincoborate-phosphate crystal is reported. Ba3(ZnB5O10)PO4, exhibits large SHG responses at 1064 and 532 nm and a short 180 nm absorption edge. Centimeter-size crystals are grown, and quantum mechanical calculations demonstrate the key role played by ZnO4 tetrahedra in the enhanced optical responses.

  12. Photographic stellar photometry with the PDS microdensitometer

    NASA Technical Reports Server (NTRS)

    Stetson, P. B.

    1979-01-01

    A technique for photographic stellar photometry with the PDS microdensitometer is described. It employs a least-squares fit to a model density profile to derive an instrumental magnitude index, an image-abnormality index, and the local value of the background density for each image. The instrumental magnitude index is calibrated in terms of true magnitude by the same methods as for iris photometry. A preliminary test of the method using plates of the open cluster NGC 188 indicates that a precision comparable to or slightly better than that of conventional iris photometry or other methods of PDS reduction may easily be attained. Possibilities for the future elaboration of the technique are mentioned.

  13. Detection of Terrestrial Planets Using Transit Photometry

    NASA Technical Reports Server (NTRS)

    Koch, David; Witteborn, Fred; Jenkins, Jon; Dunham, Edward; Boruci, William; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Transit photometry detection of planets offers many advantages: an ability to detect terrestrial size planets, direct determination of the planet's size, applicability to all main-sequence stars, and a differential brightness change of the periodic signature being independent of stellar distance or planetary orbital semi-major axis. Ground and space based photometry have already been successful in detecting transits of the giant planet HD209458b. However, photometry 100 times better is required to detect terrestrial planets. We present results of laboratory measurements of an end-to-end photometric system incorporating all of the important confounding noise features of both the sky and a space based photometer including spacecraft jitter. In addition to demonstrating an instrumental noise of less than 10 ppm (an Earth transit of a solar-like star is 80 ppm), the brightnesses of individual stars were dimmed to simulate Earth-size transit signals. These 'transits' were reliably detected as part of the tests.

  14. TRIPPy: Python-based Trailed Source Photometry

    NASA Astrophysics Data System (ADS)

    Fraser, Wesley C.; Alexandersen, Mike; Schwamb, Megan E.; Marsset, Michael E.; Pike, Rosemary E.; Kavelaars, JJ; Bannister, Michele T.; Benecchi, Susan; Delsanti, Audrey

    2016-05-01

    TRIPPy (TRailed Image Photometry in Python) uses a pill-shaped aperture, a rectangle described by three parameters (trail length, angle, and radius) to improve photometry of moving sources over that done with circular apertures. It can generate accurate model and trailed point-spread functions from stationary background sources in sidereally tracked images. Appropriate aperture correction provides accurate, unbiased flux measurement. TRIPPy requires numpy, scipy, matplotlib, Astropy (ascl:1304.002), and stsci.numdisplay; emcee (ascl:1303.002) and SExtractor (ascl:1010.064) are optional.

  15. Deep Subwavelength Optical Nanolithography

    DTIC Science & Technology

    2005-05-12

    Fresnel mirror ) where the right and left halves of the beam are folded onto each other using a 90° geometry. This arrangement has been used quite...large ar- eas –especially at periods corresponding to incidence angles θ of ~ 45° where the sizes of the beams incident on the sample and the mirror ...are equal. At extremely large or small periods, the available area becomes limited by the required size of the folding mirror and alternative

  16. Optical properties of the deep brain in the red and NIR: changes observed under in-vivo, post-mortem, frozen and formalin-fixated conditions

    NASA Astrophysics Data System (ADS)

    Pitzschke, A.; Lovisa, B.; Seydoux, O.; Zellweger, M.; Pfleiderer, M.; Haenggi, M.; Oertel, M.; Tardy, Y.; Wagnières, G.

    2015-07-01

    Photobiomodulation (PBM) is a promising approach to treat Parkinson's disease (PD) symptoms in cellular or animal models. Unfortunately, little information is available on the optical parameters playing a role in the light dosimetry during PBM. We conducted a study to determine the effective attenuation coefficient μeff of PD-relevant human deep brain tissues at 671 and 808 nm, using a multichannel fluence rate-meter comprising sub-millimeter isotropic detectors. The first step involved measurements of tissue modifications induced by postmortem situation and tissue storage on rabbit brains. The parameter μeff was measured using various tissue conditions (in vivo, immediately after sacrifice, after six weeks' storage at -20°C or in 10 % formaldehyde solution) on eight female New Zealand white rabbits. In the second step, fluence rate was measured at various locations of a frozen human deep brain when the deep brain was illuminated from the sphenoidal sinus. The results were processed by an iterative Monte-Carlo algorithm to generate sets of optical parameters, and results collected on rabbit brains were used to extrapolate the μeff value that would be observed in human deep brain tissues in vivo. Under all tissue conditions, the value of μeff at 808 nm was smaller than that at 671 nm. After long-term storage for six weeks at -20°C, μeff decreased, on average by 15 to 25 % at all wavelengths, while it increased by 5 to 15 % at all wavelengths after storage in formaldehyde. Therefore, a reasonable estimate of in vivo human deep brain μeff values at 671 and 808 nm can be obtained by multiplying the data we report by 120 %.

  17. Very deep spectroscopy of the bright Saturn nebula NGC 7009 - II. Analysis of the rich optical recombination spectrum

    NASA Astrophysics Data System (ADS)

    Fang, X.; Liu, X.-W.

    2013-03-01

    In Paper I, we presented a deep, long-slit spectrum of the bright Saturn nebula NGC 7009. Numerous permitted lines emitted by the C+, N+, O+ and Ne+ ions were detected. Gaussian profile fitting to the spectrum yielded more than 1000 lines, the majority of which are optical recombination lines (ORLs) of heavy-element ions. In the current paper, we present a critical analysis of the rich optical recombination spectrum of NGC 7009, in the context of the bi-abundance nebular model proposed by Liu et al. Transitions from individual multiplets are checked carefully for potential blended lines. The observed relative intensities are compared with the theoretical predictions based on high-quality effective recombination coefficients, now available for the recombination line spectrum of a number of heavy-element ions. The possibility of plasma diagnostics using the ORLs of various heavy-element ions is discussed in detail. The line ratios that can be used to determine electron temperature are presented for each ion, although there is still a lack of adequate atomic data and some of the lines are still not detected in the spectrum of NGC 7009 due to weakness and/or line blending. Plasma diagnostics based on the N II and O II recombination spectra both yield electron temperatures close to 1000 K, which is lower than those derived from the collisionally excited line (CEL) ratios (e.g. the [O III] and [N II] nebular-to-auroral line ratios; see Paper I for details) by nearly one order of magnitude. The very low temperatures yielded by the O II and N II ORLs indicate that they originate from very cold regions. The C2+/H+, N2+/H+, O2+/H+ and Ne2+/H+ ionic abundance ratios derived from ORLs are consistently higher, by about a factor of 5, than the corresponding values derived from CELs. In calculating the ORL ionic abundance ratios, we have used the newly available high-quality effective recombination coefficients, and adopted an electron temperature of ˜1000 K, as given by the ORL

  18. Photometry of slow X-ray pulsars. II - The 13.9 minute period of X Persei

    NASA Technical Reports Server (NTRS)

    Margon, B.; Thorstensen, J. R.; Bowyer, S.; Mason, K. O.; White, N. E.; Sanford, P. W.; Parkes, G.; Stone, R. P. S.; Bailey, J.

    1977-01-01

    Results are presented for time-resolved narrow-band photometry and spectrophotometry of X Per performed in an unsuccessful effort to confirm previously reported observations of 13.9-min pulsations in the intensity of the He II line at 4686 A. No features that are synchronous with a 13.9-min period are found in the optical data, and simultaneous X-ray observations of 3U 0352+30 are reported which show that a strong 13.9-min X-ray modulation was present during the optical photometry. Some implications of the X-ray periodicities observed for X Per are considered.

  19. An In-Situ Deep-UV Optical Probe for Examining Biochemical Presence in Deep Glaciers and Sub-Glacial Lakes

    NASA Astrophysics Data System (ADS)

    Lane, A. L.; Behar, A.; Bhartia, R.; Conrad, P. G.; Hug, W. F.

    2007-12-01

    The quest to study and understand extremophiles has led to many quite different research paths in the past 30 years. One of the more difficult directions has been the study of biochemical material in deep glacial ice and in subglacial lakes. Lake Vostok in Eastern Antarctica has been perhaps the most discussed subglacial lake because of its large size (~14,000 sq km), deep location under >3700 m of overlying ice, and thick sediment bed (~200m). Once the physical conditions of the Lake were assessed, questions immediately arose about the potential existence of biological material - either extinct or possibly extant under conditions of extremely limited energy and nutrients [1-2]. To investigate the biology of Vostok, via in-situ methods, is a major issue that awaits proven techniques that will not contaminate the Lake beyond what may have occurred to date. Lake Ellsworth, in West Antarctica, also discovered by ice penetrating radar, is of significantly smaller size, but is also >3500 m below the overlying ice. It represents a wonderful opportunity to design, engineer and build in-situ delivery systems that consider bio-cleanliness approaches to enable examination of its water, sediment bed and the "roof" area accretion ice for biochemicals [3]. Our laboratory has been developing deep UV fluorescence and UV Raman instrumentation to locate and classify organic material at a variety of extremophile locations. The confluence of the measurement techniques and the engineering for high external pressure instrument shells has enabled us to design and begin prototype fabrication of a biochemical sensing probe that can be inserted into a hot-water drilled ice borehole, functioning as a local area mapper in water environments as deep as 6000 m. Real-time command and control is conducted from a surface science station. We have been using the deep Vostok ice cores at the U.S. National Ice Core Lab to validate our science and data analysis approaches with an "inverted" system

  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. Photoelectric photometry era at the Astronomical Institute of the Slovak Academy of Sciences III. Fast photometry

    NASA Astrophysics Data System (ADS)

    Vaňko, M.; Kollár, V.; Komžík, R.; Koza, J.; Pribulla, T.

    2015-12-01

    We present a continuation of the article series describing the photoelectric photometry era at the Astronomical Institute of the Slovak Academy of Sciences. The paper aims to provide a comprehensive technical description of implementation of the fast photometry at the Stará Lesná Observatory and estimates its photometric precision. Using integration times of 0.1 s and 0.01 s, an estimated photometric precision of the fast photometry is about 0.02 mag and 0.06 mag, respectively. Here, we also show the observation principles of the fast photometry and its use in positive observation of stellar occultation lasting 18.44 s by the asteroid (85) Io.

  2. ATel 7543: NIR photometry of SNhunt 275

    NASA Astrophysics Data System (ADS)

    Richardson, Noel; Artigau, Etienne

    2015-05-01

    SNhunt 275 (PSN J09093496+3307204) appears to be behaving similarly to SN 2009ip with an eruptive mass-loss event followed by a supernova explosion. We obtained a few epochs of NIR photometry using the Observatoire du Mont Megantic 1.6 m telescope and the CPAPIR instrument (Artigau et al. ...

  3. PHOTOMETRYPIPELINE - An Automated Pipeline for Calibrated Photometry

    NASA Astrophysics Data System (ADS)

    Mommert, Michael; Moskovitz, Nicholas; Trilling, David E.

    2016-10-01

    Telescopes acquire massive amounts of imaging data every night. The goal of a large fraction of these observations is to obtain calibrated photometry for point sources - stars or moving Solar System targets - in different filters.We present PHOTOMETRYPIPELINE (PP, github.com/mommermi/photometrypipeline), an automated pipeline to obtain calibrated photometry from imaging data. PP is an open-source Python 2.7 software suite that provides image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction. For image registration, PP utilizes Source Extractor (Bertin & Arnouts 1996, A&AS, 117) and SWARP (Bertin et al. 2002, ASP Conf. S., 228) to find a plate solution for each frame, providing accurate target astrometry. Circular aperture photometry is performed using Source Extractor; an optimum aperture radius is identified using a curve-of-growth analysis. Photometric calibration is obtained through matching the background source catalog with star catalogs with reliable photometry (e.g., SDSS, URAT-1) in an iterative process; magnitude zeropoint accuracies are usually of the order of 0.03 mag, or better. Final calibrated photometry for each field source is written into a queriable database; target photometry is extracted from this database. Moving targets are identified using JPL Horizons (Giorgini et al. 1996, BAAS, 28) ephemerides. Image combination capabilities (using SWARP, Bertin 2006, ASP Conf. S., 112) are also available to improve the target's signal.PP is well-suited for data covering a few square arcminutes of the sky due to its dependence on background sources for registration and calibration. PP can be run on Unix-based systems on a simple desktop machine and is capable of realtime data analysis. PP has been developed for observations of moving targets, but can also be used on other observations. Efforts to improve the sky coverage for phometric calibration are in progress. Also, a module will be

  4. Deep level defect studies in semi-insulating 4H- and 6H-silicon carbide using optical admittance spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Wonwoo

    The objective of this study is to determine the deep vanadium defect levels in semi-insulating 4H- and 6H- silicon carbide using optical admittance spectroscopy. Also infrared spectroscopy and electron paramagnetic resonance spectroscopy are conducted to support the evidence of vanadium donor and acceptor levels obtained from OAS measurements. Vanadium acts as an amphoteric impurity in silicon carbide with a V3+/4+ acceptor level and V4+/5+ donor level. Although the value for the donor level is well established, the V3+/4+ defect level remains controversial. OAS shows that the vanadium donor level is isolated near Ec-1.7 eV, and the vanadium acceptor level is located at Ec-0.75 eV at a cubic site and Ec-0.94 eV at a hexagonal site in 4H-SiC, while the vanadium donor level of 6H-SiC samples is about Ec-1.5 eV. The acceptor levels of 6H-SiC were assigned to Ec-0.67 eV, E c -0.70 eV at two cubic sites, and Ec-0.87 eV at a hexagonal site. IR spectra demonstrated that the signatures of the vanadium V 3+ and V4+ charge states are present in the samples. EPR and photo-induced EPR are used to identify the V3+/4+ and V4+/5+ levels as well as the V3+ and V 4+ charge states. EPR spectra represent both V3+ and V4+ in 4H- and 6H samples consistent with FTIR data. EPR and photo-induced EPR suggest that the va nadium acceptor level is between 0.7 eV and 0.86 eV, while the donor level is near Ec-1.5 eV in 6H-SiC. The donor level of 4H-SiC is located at Ec-1.6 eV. Thus, the data obtained from EPR and FTIR support the assignment of the vanadium defect levels determined by OAS. Vanadium complexes induced by other elements such as titanium, hydrogen, and nitrogen atoms are also observed in OAS spectra and will be discussed in the text.

  5. Pump-tuned deep-infrared femtosecond optical parametric oscillator across 6-7  μm based on CdSiP2.

    PubMed

    Chaitanya Kumar, S; Esteban-Martin, A; Santana, A; Zawilski, K T; Schunemann, P G; Ebrahim-Zadeh, M

    2016-07-15

    We report on a high-power femtosecond optical parametric oscillator (OPO) at 80 MHz repetition rate, tunable across 6318-7061 nm in the deep-infrared (deep-IR) using pump wavelength tuning. The OPO, based on CdSiP2 (CSP), is synchronously pumped by a commercial Ti:sapphire-pumped femtosecond OPO in the near-IR, enabling rapid static tuning of the CSP OPO with minimal adjustments to its cavity length. The deep-IR CSP OPO provides as much as 32 mW of average idler power at 6808 nm with spectral bandwidth >1000  nm (at -10  dB level) across the tuning range. By implementing intracavity dispersion control, near-transform-limited signal pulses of ∼100  fs duration with smooth single-peak spectrum are achieved at 1264 nm, corresponding to an idler wavelength at 6440 nm. To the best of our knowledge, this is the first time such practical idler powers in the deep-IR have been generated from a dispersion-compensated CSP femtosecond OPO at sub-100 MHz repetition rate.

  6. Monitoring ABC-assisted deep inspiration breath hold for left-sided breast radiotherapy with an optical tracking system

    SciTech Connect

    Mittauer, Kathryn E.; Deraniyagala, Rohan; Li, Jonathan G.; Lu, Bo; Liu, Chihray; Samant, Sanjiv S.; Lightsey, Judith L.; Yan, Guanghua

    2015-01-15

    Purpose: Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided breast radiotherapy. Different breath-hold (BH) maneuvers (abdominal vs thoracic breathing) can lead to chest wall positional variations, even though the patient’s tidal volume remains consistent. This study aims to investigate the feasibility of using optical tracking for real-time quality control of active breathing coordinator (ABC)-assisted deep inspiration BH (DIBH). Methods: An in-house optical tracking system (OTS) was used to monitor ABC-assisted DIBH. The stability and localization accuracy of the OTS were assessed with a ball-bearing phantom. Seven patients with left-sided breast cancer were included. A free-breathing (FB) computed tomography (CT) scan and an ABC-assisted BH CT scan were acquired for each patient. The OTS tracked an infrared (IR) marker affixed over the patient’s xiphoid process to measure the positional variation of each individual BH. Using the BH within which the CT scan was performed as the reference, the authors quantified intra- and interfraction BH variations for each patient. To estimate the dosimetric impact of BH variations, the authors studied the positional correlation between the marker and the left breast using the FB CT and BH CT scans. The positional variations of 860 BHs as measured by the OTS were retrospectively incorporated into the original treatment plans to evaluate their dosimetric impact on breast and cardiac organs [heart and left anterior descending (LAD) artery]. Results: The stability and localization accuracy of the OTS was within 0.2 mm along each direction. The mean intrafraction variation among treatment BHs was less than 2.8 mm in all directions. Up to 12.6 mm anteroposterior undershoot, where the patient’s chest wall displacement of a BH is less than that of a reference BH, was observed with averages of 4.4, 3.6, and 0.1 mm in the anteroposterior, craniocaudal, and mediolateral directions

  7. Asteroid models from photometry and complementary data sources

    NASA Astrophysics Data System (ADS)

    Kaasalainen, Mikko

    2016-05-01

    I discuss inversion methods for asteroid shape and spin reconstruction with photometry (lightcurves) and complementary data sources such as adaptive optics or other images, occultation timings, interferometry, and range-Doppler radar data. These are essentially different sampling modes (generalized projections) of plane-of-sky images. An important concept in this approach is the optimal weighting of the various data modes. The maximum compatibility estimate, a multi-modal generalization of the maximum likelihood estimate, can be used for this purpose. I discuss the fundamental properties of lightcurve inversion by examining the two-dimensional case that, though not usable in our three-dimensional world, is simple to analyze, and it shares essentially the same uniqueness and stability properties as the 3-D case. After this, I review the main aspects of 3-D shape representations, lightcurve inversion, and the inclusion of complementary data.

  8. Macular pigment and the edge hypothesis of flicker photometry.

    PubMed

    Bone, Richard A; Landrum, John T; Gibert, Jorge C

    2004-12-01

    Heterochromatic flicker photometry is commonly used to measure macular pigment optical density (MPOD) in the human retina. It has been proposed, and accepted by many, that the MPOD so measured represents the value at a retinal location corresponding to the edge of the flickering, circular stimulus. We have investigated this proposal by using a series of annular stimuli to determine the MPOD distribution in the central 1.5 degrees of the retina for both eyes of 10 subjects. The MPOD obtained using a 1.5 degrees circular stimulus matched the MPOD distribution at a retinal eccentricity that was always less than the stimulus radius, and averaged, for the 10 subjects, 51% of the stimulus radius. Similar results were obtained using a 1 degrees stimulus. Thus the edge hypothesis is inconsistent with our data. We suggest that involuntary eye movements may be responsible for an apparent edge effect.

  9. Infrared photometry of comet Wilson (1986l) at two epochs

    NASA Technical Reports Server (NTRS)

    Hanner, Martha S.; Newburn, Ray L.

    1989-01-01

    1-20 micron filter photometry of comet Wilson (1986l) was obtained on May 29 - June 2, 1987 (r = 1.36 AU) and January 11 -14, 1988 (r = 3.75 AU) at the NASA Infrared Telescope Facility. The thermal emission at 1.36 AU has been fit with a model for a size distribution of small absorbing grains; the size and the optical properties of the dust (color, albedo, and thermal emission spectrum) appear typical of short period comets at similar r. No 10 micron silicate feature was evident. The dust-production rate on June 1 was about 5 x 10 to the 5th g/s. The geometric albedo of comet Wilson at r = 3.75 AU appears to be higher than that of comets measured at smaller r, after phase effects have been accounted for. Such albedos seem typical of comets at larger heliocentric distances.

  10. BVRI SURFACE PHOTOMETRY OF ISOLATED GALAXY TRIPLETS

    SciTech Connect

    Hernandez-Toledo, H. M.; Mendez-Hernandez, H.; Aceves, H.; OlguIn, L. E-mail: hmendez@astroscu.unam.mx E-mail: lorenzo@astro.uson.mx

    2011-03-15

    Optical broadband BVRI observations of 54 galaxies selected from the Catalog of Isolated Triplets of Galaxies in the Northern Hemisphere have been carried out at San Pedro Martir National Observatory to evaluate their photometric and morphological properties. We complement our analysis with Two-Micron All Sky Survey (2MASS) and Sloan Digital Sky Survey (SDSS) images and look for signatures likely related to interactions/mergers. We report apparent/absolute BVRI magnitudes and colors for the 54 galaxies. The membership of these galaxies is re-evaluated by imposing a reasonable condition of concordant redshifts upon the original selection criteria, rendering a final sample of 34 galaxies in 13 triplets, 12 galaxies in close pairs, and 8 galaxy outliers. The triplets are spiral-dominated systems in different dynamical stages from loosely interacting to almost merged objects. The incidence fraction of features likely associated with interactions is {approx}56%, similar to those found in northern and southern compact groups. The average fraction of bars is 35% with a mean value of maximum bar ellipticity {epsilon}{sub max} {approx} 0.4. Bars are hosted in the late-type triplet spirals, almost twice more than in early-type spirals. The global fraction of rings is 20%, all in the late-type components. The overdensity of triplets with respect to the background and their current dynamical status, as devised from our estimate of their dynamical parameters, namely the harmonic radius R{sub H} , velocity dispersion {sigma}, dimensionless crossing time H{sub 0{tau}c}, and virial mass M{sub V} , appear to be sufficient to favor galaxy transformations similar to those seen in dense groups and clusters. By contrast, the lower fraction of bonafide ellipticals and the relatively higher fraction of late-type spirals make these triplets essentially different from the Hickson Compact Groups and more representative of the field. A modest 1.6 enhancement factor in the optical luminosity

  11. Determination of optical cross sections for electron and hole emission from deep defects in low-temperature-grown GaAs

    NASA Astrophysics Data System (ADS)

    Malzer, S.; Steen, C.; Kiesel, P.; Döhler, G. H.

    2005-06-01

    We report on optical cross sections of electrons and holes in thin layers of LT-GaAs embedded in hetero-pin-diodes. With an appropriate design, the time dependent change of the n-layer conductance directly reflects the change in the charge state of the deep levels. The original completely filled (or empty) defect states can be created by an electrical bias or illumination by laser light. For samples annealed at 700 °C we find a defect signature very similar to the EL2 defect in the literature.

  12. Feasibility Study on Acquisition, Tracking, and Pointing Using Earth Thermal Images for Deep-Space Ka-Band and Optical Communications

    NASA Astrophysics Data System (ADS)

    Lee, S.; Ortiz, G. G.; Roberts, W. T.; Alexander, J. W.

    2003-11-01

    The feasibility of using long-wavelength Earth thermal (infrared) images for antenna/ telescope tracking/pointing applications for both deep-space Ka-band (18 to 35 GHz) and free-space optical communications has been investigated and is reported on here. The advantage of this technology rests on using full Earth images in this band that yield more accurate estimates of geometric centroids than those of Earth images in the visible band. Furthermore, these images are nearly independent of Earth phase angle. The results of the study show that, at a Mars range with currently available sensors, a noise equivalent angle of 10 to 150 nrad and a bias error of better than 80 nrad can be obtained. This would enable precise pointing of both the optical and Ka-band communications beams.

  13. UBV photometry of hot white dwarf stars

    NASA Astrophysics Data System (ADS)

    Cheselka, Mathew; Holberg, J. B.; Watkins, Ron; Collins, James; Tweedy, R. W.

    1993-12-01

    Johnson UBV photometry has been obtained for a set of hot degenerate stars, primarily DA and DO white dwarfs from among those detected in the Palomar-Green survey of UV excess objects. Most of our program stars have estimated effective temperatures (Teff) in the range 22,000 to 80,000 K and have no previous photometry. Some objects selected are also x-ray and extreme ultraviolet sources from the ROSAT all sky survey. The importance of precise photometric measurements in the analysis of x-ray data is discussed. A discrepancy between the observed colors and predicted colors is noted, and possibly accounted for by difficulties in defining the atmospheric cutoff of the U band and a general lack of hot stars used to define the photometric transformation between theoretical and observed colors.

  14. MOVING OBJECTS IN THE HUBBLE ULTRA DEEP FIELD

    SciTech Connect

    Kilic, Mukremin; Gianninas, Alexandros; Von Hippel, Ted E-mail: alexg@nhn.ou.edu

    2013-09-01

    We identify proper motion objects in the Hubble Ultra Deep Field (UDF) using the optical data from the original UDF program in 2004 and the near-infrared data from the 128 orbit UDF 2012 campaign. There are 12 sources brighter than I = 27 mag that display >3{sigma} significant proper motions. We do not find any proper motion objects fainter than this magnitude limit. Combining optical and near-infrared photometry, we model the spectral energy distribution of each point-source using stellar templates and state-of-the-art white dwarf models. For I {<=} 27 mag, we identify 23 stars with K0-M6 spectral types and two faint blue objects that are clearly old, thick disk white dwarfs. We measure a thick disk white dwarf space density of 0.1-1.7 Multiplication-Sign 10{sup -3} pc{sup -3} from these two objects. There are no halo white dwarfs in the UDF down to I = 27 mag. Combining the Hubble Deep Field North, South, and the UDF data, we do not see any evidence for dark matter in the form of faint halo white dwarfs, and the observed population of white dwarfs can be explained with the standard Galactic models.

  15. Hubble Deep Fields

    NASA Astrophysics Data System (ADS)

    Ferguson, H.; Murdin, P.

    2000-11-01

    The Hubble Deep Fields are two small areas of the sky that were carefully selected for deep observations by the HUBBLE SPACE TELESCOPE (HST). They represent the deepest optical observations to date and reveal galaxies as faint as V=30, 4 billion times fainter than can be seen with the unaided eye....

  16. HST BVI Photometry of Triton and Proteus

    DTIC Science & Technology

    2006-09-15

    rights reserved. Keywords: Triton ; Satellites, surfaces; Neptune , magnetosphere1. Introduction Triton is an enigmatic satellite—seemingly without a...2003. The BVRI and methane lightcurve of Triton in 2003. Bull. Am. As- tron. Soc. 35, 1483. Smith, B., and 64 colleagues, 1989. Voyager 2 at Neptune ...Icarus 185 (2006) 487–491 www.elsevier.com/locate/icarus HST BVI photometry of Triton and Proteus Dan Pascu a,∗, Alex D. Storrs b, Eddie N. Wells c,1

  17. WISE PHOTOMETRY FOR 400 MILLION SDSS SOURCES

    SciTech Connect

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-02-15

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star–galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me.

  18. WISE Photometry for 400 Million SDSS Sources

    NASA Astrophysics Data System (ADS)

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-02-01

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star-galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me.

  19. Lightcurve Photometry Opportunities: 2016 April-June

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2016-04-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  20. Lightcurve Photometry Opportunities: 2017 January-March

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2017-01-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  1. Lightcurve Photometry Opportunities: 2016 July-September

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2016-07-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  2. Lightcurve Photometry Opportunities: 2016 October-December

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2016-10-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  3. Lightcurve Photometry Opportunities: 2017 April-June

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2017-04-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  4. Variable Star Photometry at West Challow Observatory

    NASA Astrophysics Data System (ADS)

    Boyd, D.

    2007-05-01

    This paper describes the facilities and observing programme of a small personal observatory set up in the UK for CCD photometry of variable stars. Its development has been driven by the belief that committed amateurs can make a valuable scientific contribution to the study of variable stars. Observing projects carried out at WCO are described including examples of Pro-Am collaboration and contributions to the observing programmes of the BAAVSS, AAVSO and CBA.

  5. PHOTOMETRYPIPELINE: An automated pipeline for calibrated photometry

    NASA Astrophysics Data System (ADS)

    Mommert, M.

    2017-01-01

    PHOTOMETRYPIPELINE (PP) is an automated pipeline that produces calibrated photometry from imaging data through image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction. PP utilizes the widely used Source Extractor software for source identification and aperture photometry; SCAMP is used for image registration. Both image registration and photometric calibration are based on matching field stars with star catalogs, requiring catalog coverage of the respective field. A number of different astrometric and photometric catalogs can be queried online. Relying on a sufficient number of background stars for image registration and photometric calibration, PP is well-suited to analyze data from small to medium-sized telescopes. Calibrated magnitudes obtained by PP are typically accurate within ≤0.03 mag and astrometric accuracies are of the order of 0.3 arcsec relative to the catalogs used in the registration. The pipeline consists of an open-source software suite written in Python 2.7, can be run on Unix-based systems on a simple desktop machine, and is capable of realtime data analysis. PP has been developed for observations of moving targets, but can be used for analyzing point source observations of any kind.

  6. Surface photometry of WINGS galaxies with GASPHOT

    NASA Astrophysics Data System (ADS)

    D'Onofrio, M.; Bindoni, D.; Fasano, G.; Bettoni, D.; Cava, A.; Fritz, J.; Gullieuszik, M.; Kjærgaard, P.; Moretti, A.; Moles, M.; Omizzolo, A.; Poggianti, B. M.; Valentinuzzi, T.; Varela, J.

    2014-12-01

    Aims: We present the B, V, and K band surface photometry catalogs obtained by running the automatic software GASPHOT on galaxies from the WINGS cluster survey with isophotal areas larger than 200 pixels. The catalogs can be downloaded at the Centre de Données Astronomiques de Strasbourg. Methods: The luminosity growth curves of stars and galaxies in a given catalog relative to a given cluster image were obtained simultaneously by slicing the image with a fixed surface brightness step in several SExtractor runs. Then, using a single Sersic law convolved with a space-varying point spread function (PSF), GASPHOT performed a simultaneous χ2 best-fit of the major- and minor-axis luminosity growth curves of galaxies. We outline the GASPHOT performances and compare our surface photometry with that obtained by SExtractor, GALFIT, and GIM2D. This analysis is aimed at providing statistical information about the accuracy that is generally achieved by the softwares for automatic surface photometry of galaxies. Results: The GASPHOT catalogs provide the parameters of the Sersic law that fit the luminosity profiles for each galaxy and for each photometric band. They are the sky coordinates of the galaxy center (RA, Dec), the total magnitude (m), the semi-major axis of the effective isophote (Re), the Sersic index (n), the axis ratio (b/a), and a flag parameter (QFLAG) that generally indicates the fit quality. The WINGS-GASPHOT database includes 41 463 galaxies in the B band, 42 275 in the V band, and 71 687 in the K band. The bright early-type galaxies have higher Sersic indices and larger effective radii, as well as redder colors in their center. In general, the effective radii increase systematically from the K to the V and B band. Conclusions: The GASPHOT photometry agrees well with the surface photometry obtained by GALFIT and GIM2D, and with the aperture photometry provided by SExtractor. In particular, the direct comparison of structural parameters derived by different

  7. DEEP NEAR-IR OBSERVATIONS OF THE GLOBULAR CLUSTER M4: HUNTING FOR BROWN DWARFS

    SciTech Connect

    Dieball, A.; Bedin, L. R.; Knigge, C.; Rich, R. M.; Allard, F.; Dotter, A.; Richer, H.; Zurek, D.

    2016-01-20

    We present an analysis of deep Hubble Space Telescope (HST)/Wide Field Camera 3 near-IR (NIR) imaging data of the globular cluster (GC) M4. The best-photometry NIR color–magnitude diagram (CMD) clearly shows the main sequence extending toward the expected end of the hydrogen-burning limit and going beyond this point toward fainter sources. The white dwarf (WD) sequence can be identified. As such, this is the deepest NIR CMD of a GC to date. Archival HST optical data were used for proper-motion cleaning of the CMD and for distinguishing the WDs from brown dwarf (BD) candidates. Detection limits in the NIR are around F110W ≈ 26.5 mag and F160W ≈ 27 mag, and in the optical around F775W ≈ 28 mag. Comparing our observed CMDs with theoretical models, we conclude that we have reached beyond the H-burning limit in our NIR CMD and are probably just above or around this limit in our optical–NIR CMDs. Thus, any faint NIR sources that have no optical counterpart are potential BD candidates, since the optical data are not deep enough to detect them. We visually inspected the positions of NIR sources that are fainter than the H-burning limit in F110W and for which the optical photometry did not return a counterpart. We found in total five sources for which we did not get an optical measurement. For four of these five sources, a faint optical counterpart could be visually identified, and an upper optical magnitude was estimated. Based on these upper optical magnitude limits, we conclude that one source is likely a WD, one source could be either a WD or BD candidate, and the remaining two sources agree with being BD candidates. No optical counterpart could be detected for just one source, which makes this source a good BD candidate. We conclude that we found in total four good BD candidates.

  8. Swept-source optical coherence tomography powered by a 1.3-μm vertical cavity surface emitting laser enables 2.3-mm-deep brain imaging in mice in vivo

    PubMed Central

    Choi, Woo June; Wang, Ruikang K.

    2015-01-01

    Abstract. We report noninvasive, in vivo optical imaging deep within a mouse brain by swept-source optical coherence tomography (SS-OCT), enabled by a 1.3-μm vertical cavity surface emitting laser (VCSEL). VCSEL SS-OCT offers a constant signal sensitivity of 105 dB throughout an entire depth of 4.25 mm in air, ensuring an extended usable imaging depth range of more than 2 mm in turbid biological tissue. Using this approach, we show deep brain imaging in mice with an open-skull cranial window preparation, revealing intact mouse brain anatomy from the superficial cerebral cortex to the deep hippocampus. VCSEL SS-OCT would be applicable to small animal studies for the investigation of deep tissue compartments in living brains where diseases such as dementia and tumor can take their toll. PMID:26447860

  9. Swept-source optical coherence tomography powered by a 1.3-μm vertical cavity surface emitting laser enables 2.3-mm-deep brain imaging in mice in vivo

    NASA Astrophysics Data System (ADS)

    Choi, Woo June; Wang, Ruikang K.

    2015-10-01

    We report noninvasive, in vivo optical imaging deep within a mouse brain by swept-source optical coherence tomography (SS-OCT), enabled by a 1.3-μm vertical cavity surface emitting laser (VCSEL). VCSEL SS-OCT offers a constant signal sensitivity of 105 dB throughout an entire depth of 4.25 mm in air, ensuring an extended usable imaging depth range of more than 2 mm in turbid biological tissue. Using this approach, we show deep brain imaging in mice with an open-skull cranial window preparation, revealing intact mouse brain anatomy from the superficial cerebral cortex to the deep hippocampus. VCSEL SS-OCT would be applicable to small animal studies for the investigation of deep tissue compartments in living brains where diseases such as dementia and tumor can take their toll.

  10. A Multi-Band Analytical Algorithm for Deriving Absorption and Backscattering Coefficients from Remote-Sensing Reflectance of Optically Deep Waters

    NASA Technical Reports Server (NTRS)

    Lee, Zhong-Ping; Carder, Kendall L.

    2001-01-01

    A multi-band analytical (MBA) algorithm is developed to retrieve absorption and backscattering coefficients for optically deep waters, which can be applied to data from past and current satellite sensors, as well as data from hyperspectral sensors. This MBA algorithm applies a remote-sensing reflectance model derived from the Radiative Transfer Equation, and values of absorption and backscattering coefficients are analytically calculated from values of remote-sensing reflectance. There are only limited empirical relationships involved in the algorithm, which implies that this MBA algorithm could be applied to a wide dynamic range of waters. Applying the algorithm to a simulated non-"Case 1" data set, which has no relation to the development of the algorithm, the percentage error for the total absorption coefficient at 440 nm a (sub 440) is approximately 12% for a range of 0.012 - 2.1 per meter (approximately 6% for a (sub 440) less than approximately 0.3 per meter), while a traditional band-ratio approach returns a percentage error of approximately 30%. Applying it to a field data set ranging from 0.025 to 2.0 per meter, the result for a (sub 440) is very close to that using a full spectrum optimization technique (9.6% difference). Compared to the optimization approach, the MBA algorithm cuts the computation time dramatically with only a small sacrifice in accuracy, making it suitable for processing large data sets such as satellite images. Significant improvements over empirical algorithms have also been achieved in retrieving the optical properties of optically deep waters.

  11. Multi-channel photon migration study in visible Chinese human muscle for optical detection of deep vein thrombosis

    NASA Astrophysics Data System (ADS)

    Sun, Yunlong; Li, Ting

    2016-03-01

    Deep vein thrombosis (DVT) always induced venous thrombosis. Most cases of venous thrombosis were induced by deep vein thrombosis (DVT), with high incidence rate of >60% in >60 years old people. Near-infrared spectroscopy (NIRS) were reported recently to be an intriguing and potential technique in detecting DVT in clinics. However, the photon transport is still unclear, which is crucial for the image reconstruction of the updated development called as NIRS-based DVT imager. Here we employed the Monte Carlo simulation software for 3D voxelized media (MCVM) and the Visible Chinese Human (VCH) model, which segmentation is finest in the world, to simulate multi-channel photon migration in calf muscle. And the image reconstruction of DVT hemodynamic distribution was achieved. This study, for the first time, provides the most realistic 3-D multichannel photon migration for NIRS study on DVT, and explored the image reconstruction for furtherly developing a NIRS-based DVT imager.

  12. Outer planet Grand Tour missions photometry/polarimetry experiment critical components study

    NASA Technical Reports Server (NTRS)

    Pellicori, S. F.; Russell, E. E.; Watts, L. A.

    1972-01-01

    Work performed during this effort was limited to two primary areas of technical concern: optical design optimization, and sensor selection. An optical system concept was established, and various system components were evaluated through experimental test sequences. Photodetectors were investigated for the applicability in meeting OPGT requirements as constrained by the photometry/polarimetry team directives. The most promising (gallium arsenide PMT) was further experimentally tested to ascertain its behavior with respect to anticipated environmental conditions. Results of testing and summary of the preceding tradeoff study effort are presented.

  13. VizieR Online Data Catalog: Spitzer photometry of globulars in 2 galaxies (Spitler+, 2008)

    NASA Astrophysics Data System (ADS)

    Spitler, L. R.; Forbes, D. A.; Beasley, M. A.

    2010-06-01

    Catalogues are described in Spitler et al. (2008MNRAS.389.1150S) All photometry is corrected for Galactic dust extinction and are on the Vega photometric system. NGC 5128 optical photometry is from Peng et al. (2004ApJS..150..367P), as compiled in Woodley et al. (2007AJ....134..494W). Globular cluster identification numbers are from Woodley et al. (2007, Cat. J/AJ/134/494). NGC 4594 optical photometry is from Spitler et al. (2006AJ....132.1593S) updated with new aperture corrections as described in Harris et al. (2010MNRAS.401.1965H). Identification number, globular cluster half-light radii and the assumed distance modulus for the half-light radii are from Spitler et al. (2006, Cat. J/AJ/132/1593). A ultra-compact dwarf galaxy is included in this catalogue with ID="ucd" (see also Hau et al. 2009MNRAS.394L..97H). (2 data files).

  14. Photometry and polarimetry of V 1057 Cygni.

    NASA Technical Reports Server (NTRS)

    Rieke, G.; Lee, T.; Coyne, G.

    1972-01-01

    Evaluation of extensive photometric and polarimetric data over a six-month interval for V 1057 Cyg. The polarization appears to be constant and of interstellar origin; the photometry, which extends nearly six octaves from the ultraviolet to 22 microns in the infrared, indicates that the total observed luminosity is decreasing - having now declined about 10% from its earlier level. A model characterized by two circumstellar shells which absorb and reradiate short-wavelength stellar flux from an underlying A1-type star provides the best fit to the observational data. The present variability, however, cannot be due to circumstellar activity, but appears to originate in the star itself.

  15. Photometry of Pluto during the 1982 opposition

    NASA Astrophysics Data System (ADS)

    Binzel, R. P.; Mulholland, J. D.

    1983-02-01

    Observations of Pluto's brightness were obtained by two-channel photometry on 18 nights during the 1982 opposition, using the 2.1-m and 91-cm reflectors at Mt. Locke. The resulting light curve suggests that the 'secular' decrease in intrinsic brightness is flattening, qualitatively consistent with a latitude dependence of the surface albedo distribution. Speculations are projected for the long-term behavior of the apparent light curve. Understanding of the current rotational brightness variation is important to the maximum utilization of photometric observations obtained during the imminent series of mutual eclipses between Pluto and its satellite.

  16. Quick and Dirty WFPC2 Stellar Photometry

    NASA Technical Reports Server (NTRS)

    Mighell, Kenneth J.

    2001-01-01

    The latest release of the IRAF (Image Reduction and Analysis Facility) MXTOOLS package includes the new tasks QDWFPC2 (Quick and Dirty Wide Field and Planetary Camera, which does quick CCD (charge-coupled device) stellar photometry on two Hubble Space Telescope (HST) WFPC2 (Wide Field and Planetary Camera) observations: WFPC2COLOR, which converts HST WFPC2 instrumental magnitudes to standard colors using the Holtzman et al. color equations, and QDCMD (Quick and Dirty Color Magnitude Diagram), which reads the output of WFPC2COLOR and displays a color-magnitude diagram on a user-chosen graphics device.

  17. Photometry of six radar target asteroids

    NASA Technical Reports Server (NTRS)

    Wisniewski, W. Z.

    1987-01-01

    Photoelectric photometry of six earth-approaching asteroids is presented. The selection criterion was that they were close enough in 1986 to be observed by radar. Rotation periods were obtained for 1986 DA, 3199, 3103, and 1983 RD. 1986 JK and 1986 RA showed no detectable brightness variations during the monitoring time on several nights each, and therefore were either seen pole-on or have long rotation periods. Asteroids 1986 JK and 1986 RA are of taxonomic class C, 1986 DA and 3103 of class X, 1983 RD of class Q, and only 3199 of the class S that was previously believed to be predominant among earth-approaching asteroids.

  18. Photometry and Astrometry of the Jovian satellites Amalthea and Thebe

    NASA Astrophysics Data System (ADS)

    Saquet, Eléonore; Emelyanov, Nicolai; Colas, François; Robert, Vincent; Arlot, Jean-Eudes

    2016-10-01

    During the 2014-2015 campaign of mutual events, we realized ground-based observations of Amalthea (JV) and Thebe (JXIV). We recorded two eclipses of Amalthea and, for the first time, one of Thebe by the Galilean moons. We used the 1-m telescope at Pic du Midi Observatory with an IR filter and a mask placed over the planetary image to reduce the light intensity of Jupiter. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60-cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. We provide astrometric results derived from the photometry with an overall accuracy of 34 mas, or 100 km at Jupiter.In the same time, we realized 45 astrometric observations of Amalthea and 41 of Thebe to compare the photometric technique with direct astrometry, using the UCAC4 reference star catalog. We provide astrometric results with an overall accuracy of 100 mas for Amalthea, or 300 km at Jupiter, and 90 mas for Thebe, or 270 km at Jupiter. These results are better than those from previous ground-based and old reduced space measurements.

  19. On the optical evaluation of the EL2 deep level concentration in semi-insulating GaAs

    NASA Technical Reports Server (NTRS)

    Walukiewicz, W.; Lagowski, J.; Gatos, H. C.

    1983-01-01

    A practical procedure for the evaluation of the Fermi energy in semi-insulating (SI)GaAs from electrical measurements is presented. This procedure makes it possible to reliably extend the determination of the major deep level (EL2) concentration, by near-infrared absorption measurements, to SIGaAs. Employing this procedure, it is shown that the EL2 concentration in Czochralski-grown GaAs increases monotonically with increasing As/Ga ratio (throughout the conversion from SI n type to semiconducting p-type crystals) rather than abruptly as previously proposed.

  20. Sky Brightness Analysis using a Million Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) Observations

    DTIC Science & Technology

    2012-09-01

    March 1989. [3] K. Krisciunas. Optical night-sky brightness at mauna kea over the course of a complete sunspot cycle. Astronomical Society of the Pacific...fsID=170&page=1, July 2012. [2] R. H. Garstang. Night-sky brightness at observatories and sites. Astronomical Society of the Pacific, 101:306–329

  1. Development of state-of-the-art optical sensors for the monitoring of deep sea umbilicals and flexible pipelines

    NASA Astrophysics Data System (ADS)

    Bettini, P.; Bertoli, S.; Sala, G.; Gaspari, R.; Pozzati, G.

    2012-04-01

    In the search for new deposits petrochemical extraction Companies are searching in challenging environments as deep sea-beds. At the same time, especially following the Gulf of Mexico disaster, there is a justified concern about the assessment of the installed asset condition. The Aerospace Engineering Department of the Politecnico di Milano and Prysmian Group R&D Department are currently carrying over a joint research project aiming to the development of new methods for the testing and evaluation of health status and conditions to be applied in the field of deep sub-sea umbilical normally employed for the petrochemical hydrocarbon extraction. The monitoring methods and the measurement system under joint development will enable Prysmian to validate vs. full scale measurement the design analytical tools currently utilized to analyze the developed elements versus the operational scenarios for which any particular umbilical is currently designed. Additionally, together with the Politecnico di Milano, Prysmian will develop a real-time measurement system to be utilized, during operational lifetime, for the asset management of the produced sub-sea umbilicals.

  2. Calibration of the MACHO photometry database

    SciTech Connect

    Alcock, A

    1998-10-23

    The MACHO Project is a microlensing survey that monitors the brightnesses of ~60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. The database presently contains more photometric measurements than previously recorded in the history of astronomy. We describe the calibration of the MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. This allows for proper comparison with all other observations on the Kron-Cousins standard system. The highest precision calibrations are for ~9 million stars in the LMC bar. For these stars, independent photometric measurements in field-overlap regions indicate standard deviations δvR = 0.020 mag. Calibrated MACHO photometry data are compared with published photometric sequences and with new Hubble Space Telescope observations. We additionally describe the first application of these calibrated data: the construction of the "efficiency" color-magnitude diagram which will be used to calculate our experimental sensitivity for detecting microlensing in the LMC.

  3. TRIPPy: Trailed Image Photometry in Python

    NASA Astrophysics Data System (ADS)

    Fraser, Wesley; Alexandersen, Mike; Schwamb, Megan E.; Marsset, Michaël; Pike, Rosemary E.; Kavelaars, J. J.; Bannister, Michele T.; Benecchi, Susan; Delsanti, Audrey

    2016-06-01

    Photometry of moving sources typically suffers from a reduced signal-to-noise ratio (S/N) or flux measurements biased to incorrect low values through the use of circular apertures. To address this issue, we present the software package, TRIPPy: TRailed Image Photometry in Python. TRIPPy introduces the pill aperture, which is the natural extension of the circular aperture appropriate for linearly trailed sources. The pill shape is a rectangle with two semicircular end-caps and is described by three parameters, the trail length and angle, and the radius. The TRIPPy software package also includes a new technique to generate accurate model point-spread functions (PSFs) and trailed PSFs (TSFs) from stationary background sources in sidereally tracked images. The TSF is merely the convolution of the model PSF, which consists of a moffat profile, and super-sampled lookup table. From the TSF, accurate pill aperture corrections can be estimated as a function of pill radius with an accuracy of 10 mmag for highly trailed sources. Analogous to the use of small circular apertures and associated aperture corrections, small radius pill apertures can be used to preserve S/Ns of low flux sources, with appropriate aperture correction applied to provide an accurate, unbiased flux measurement at all S/Ns.

  4. JHK photometry of selected Trojan and Hilda asteroids

    NASA Technical Reports Server (NTRS)

    Smith, Dale W.; Johnson, Paul E.; Buckingham, William L.; Shorthill, Richard W.

    1992-01-01

    No entirely satisfactory match has been established between the present JHK photometry of selected Hilda and Trojan asteroids and photometry for both main belt asteroids and laboratory samples. It is noted that while the leading Trojans and Hildas exhibit similar and homogeneous JHK colors, the trailing Trojans appear to be more heterogeneous. Charcoal and magnetite provide the best match in terms of JHK colors.

  5. The DEEP-South: Network Construction and Test Operations

    NASA Astrophysics Data System (ADS)

    Moon, Hong-Kyu; Kim, Myung-Jin; Yim, Hong-Suh; Choi, Young-Jun; Bae, Youngho; Roh, Dong-Goo; the DEEP-South Team

    2015-08-01

    Korea Astronomy and Space Science Institute achieved completion of a network of optical telescopes called the KMTNet (Korea Micro-lensing Telescope Network) in the end of 2014. The KMTNet is comprised of three 1.6-m prime focus wide-field optics and 18K×18K mosaic CCDs, each providing 2×2 degrees field of view. This network facilities located at CTIO (Chile), SAAO (South Africa), and SSO (Australia) are expected to be on line in mid-2015 with their CCDs fully functional. While its primary objective is discovery and characterization of extrasolar planets, it is also being used for “Deep Ecliptic Patrol of the Southern Sky (DEEP-South)” aiming at asteroid and comet studies as one of its secondary science projects. The KMTNet telescopes are almost equally separated in longitude, and hence enable a 24-hour uninterrupted monitoring of the southern sky. The DEEP-South will thus provide a prompt solution to a demand from the scientific community to bridge the gaps in global sky coverage with a coordinated use of a network of ground-based telescopes in the southern hemisphere. Thanks to round-the-clock capability orbits, spin states and three dimensional shape of an object will be systematically investigated and archived for the first time. Based on SDSS and BVRI colors, we will also constrain their surface mineralogy, with an emphasis on targeted photometry of km-sized Potentially Hazardous Asteroids (PHAs) in the first stage (2015-2019). In the end of 2015, we plan to complete implementing dedicated software subsystem made of an automated observation scheduler and data pipeline for the sake of an increased discovery rate, rapid follow-up, timely phase coverage, and more efficient data reduction and analysis. We will give a brief introduction to a series of test operations conducted at the KMTNet-CTIO in February, March and April in 2015 with experimental data processing. Preliminary scientific results will also be presented.

  6. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Optical spectroscopy of laser plasma in a deep crater

    NASA Astrophysics Data System (ADS)

    Kononenko, Taras V.; Walter, D.; Konov, Vitalii I.; Dausinger, F.

    2009-04-01

    The time dynamics of plasma-emission spectra is studied experimentally at different stages of the drilling of a steel plate by 100-fs and 5-ps laser pulses: from a shallow crater to a hole. The change in the time dependence of the plasma temperature caused by variations in the irradiated surface geometry is analysed. It is found that the time interval needed to reach a particular temperature (about 8000 K) drastically increases from 40-50 to 150-200 ns when a specific crater depth is achieved. The opposite tendency is observed as the crater depth grows further and a hole is produced. Strong self-absorption in a plasma plume inside a deep crater is experimentally confirmed which results in the appearance of line absorption against a continuous emission spectrum.

  7. Optical and EPR Spectroscopic Studies of Deep Red Light Emitting Fe-Doped LiAl5O8 Phosphor Prepared Via Propellant Combustion Route

    NASA Astrophysics Data System (ADS)

    Singh, Vijay; Sivaramaiah, G.; Rao, J. L.; Singh, N.; Mohapatra, M.; Singh, P. K.; Pathak, M. S.; Dhoble, S. J.

    2016-12-01

    LiAl5O8 doped with Fe was synthesized by a propellant combustion route at furnace temperature of 773 K. The phosphor was characterized using powder x-ray diffraction, optical absorption, electron paramagnetic resonance (EPR) and photoluminescence spectroscopic techniques. The optical absorption spectrum exhibits a broad band at 242 nm characteristic of charge transfer between Fe3+-O2-. On excitation with 293 nm, emission band for the Fe3+ ion was observed at 687 nm. The CIE (International Commission on Illumination or Commission Internationale de l'Elcairage) coordinates for the system were evaluated adopting standard procedure which suggested that the system can be effective as a deep red emitting phosphor. The EPR spectrum of this phosphor exhibits a number of resonance signals characteristic of Fe3+ ions. The resonance signals at g = 3.16, 2.27 are attributed to Fe3+ present at tetrahedral site with an axial symmetry. The resonance signals at g = 1.98 and 1.43 are attributed to Fe3+ ions in octahedral site with an axial symmetry. Various EPR parameters such as the number of spins, Gibbs free energy, magnetic susceptibility, Curie constant and effective magnetic moment values are calculated and compared at room temperature and 110 K.

  8. Beryllium-free Rb3Al3B3O10F with reinforced interlayer bonding as a deep-ultraviolet nonlinear optical crystal.

    PubMed

    Zhao, Sangen; Gong, Pifu; Luo, Siyang; Liu, Sijie; Li, Lina; Asghar, Muhammad Adnan; Khan, Tariq; Hong, Maochun; Lin, Zheshuai; Luo, Junhua

    2015-02-18

    A new beryllium-free borate Rb3Al3B3O10F has been synthesized and characterized by single-crystal X-ray diffraction. It features a framework structure consisting of alveolate [Al3(BO3)3OF]∞ layers tightly bound via Al-O and Al-F bridged bonds, with the in-layer [BO3](3-) groups in nearly coplanar and aligned arrangement. This compound is transparent down to 200 nm and is phase-matchable with a powder second-harmonic generation efficiency of 1.2 times that of KH2PO4. Remarkably, it exhibits a strong interlayer bonding which is about one order larger than that of the benchmark KBe2BO3F2, thus no layering tendency was observed during the crystal growth. In addition, it is nonhygroscopic and thermally stable up to ∼1462 K. These attributes make Rb3Al3B3O10F a promising nonlinear optical crystal in the deep-ultraviolet region. First-principles calculations, combined with the anionic group theory, were adopted to rationalize the optical properties.

  9. Optical and EPR Spectroscopic Studies of Deep Red Light Emitting Fe-Doped LiAl5O8 Phosphor Prepared Via Propellant Combustion Route

    NASA Astrophysics Data System (ADS)

    Singh, Vijay; Sivaramaiah, G.; Rao, J. L.; Singh, N.; Mohapatra, M.; Singh, P. K.; Pathak, M. S.; Dhoble, S. J.

    2017-03-01

    LiAl5O8 doped with Fe was synthesized by a propellant combustion route at furnace temperature of 773 K. The phosphor was characterized using powder x-ray diffraction, optical absorption, electron paramagnetic resonance (EPR) and photoluminescence spectroscopic techniques. The optical absorption spectrum exhibits a broad band at 242 nm characteristic of charge transfer between Fe3+-O2-. On excitation with 293 nm, emission band for the Fe3+ ion was observed at 687 nm. The CIE (International Commission on Illumination or Commission Internationale de l'Elcairage) coordinates for the system were evaluated adopting standard procedure which suggested that the system can be effective as a deep red emitting phosphor. The EPR spectrum of this phosphor exhibits a number of resonance signals characteristic of Fe3+ ions. The resonance signals at g = 3.16, 2.27 are attributed to Fe3+ present at tetrahedral site with an axial symmetry. The resonance signals at g = 1.98 and 1.43 are attributed to Fe3+ ions in octahedral site with an axial symmetry. Various EPR parameters such as the number of spins, Gibbs free energy, magnetic susceptibility, Curie constant and effective magnetic moment values are calculated and compared at room temperature and 110 K.

  10. Absolute flux calibration of optical spectrophotometric standard stars

    NASA Technical Reports Server (NTRS)

    Colina, Luis; Bohlin, Ralph C.

    1994-01-01

    A method based on Landolt photometry in B and V is developed to correct for a wavelength independent offset of the absolute flux level of optical spectrophotometric standards. The method is based on synthetic photometry techniques in B and V and is accurate to approximately 1%. The correction method is verified by Hubble Space Telescope Faint Object Spectrograph absolute fluxes for five calibration stars, which agree with Landolt photometry to 0.5% in B and V.

  11. Kron-Cousins Optical Photometry of SN 2009ip

    NASA Astrophysics Data System (ADS)

    Leonard, D. C.; Fedrow, J. M.; Khandrika, H. G.; Gonzalez, L.

    2012-09-01

    Following a report (Smith & Mauerhan, ATel #4412) of spectral changes on 2012 Sept. 15 and 16 (JD 2456185 and JD 2456186) that suggested a transition from LBV-like eruptions (Smith et al. 2010; Foley et al. 2011; Drake et al. 2012, ATel #4334) to a true SN IIn explosion, photometric observations of the transient SN 2009ip have indicated dimming (Margutti et al., ATel #4414; Martin et al., ATel #4416) followed by significant recent brightening (Brimacombe, ATel #4423; Margutti et al., ATel #4425) of the transient.

  12. Simultaneous Multi-Filter Optical Photometry of GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Cowardin, Heather; Barker, Edwin S.; Abercromby, Kira; Kelecy, Thomas

    2011-01-01

    Information on the physical characteristics of unresolved pieces of debris comes from an object's brightness, and how it changes with time and wavelength. True colors of tumbling, irregularly shaped objects can be accurately determined only if the intensity at all wavelengths is measured at the same time. In this paper we report on simultaneous photometric observations of objects at geosynchronous orbit (GEO) using two telescopes at Cerro Tololo Inter-American Observatory (CTIO). The CTIO/SMARTS 0.9-m observes in a Johnson B filter, while the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope) observes in a Cousins R filter. The two CCD cameras are electronically synchronized so that the exposure start time and duration are the same for both telescopes. Thus we obtain the brightness as a function of time in two passbands simultaneously, and can determine the true color of the object at any time. We will report here on such calibrated measurements made on a sample of GEO objects and what is the distribution of the observed B-R colors. In addition, using this data set, we will show what colors would be observed if the observations in different filters were obtained sequentially, as would be the case for conventional imaging observations with a single detector on a single telescope. Finally, we will compare our calibrated colors of GEO debris with colors determined in the laboratory of selected materials actually used in spacecraft construction.

  13. Further Rapid Optical Photometry of V404 Cyg

    NASA Astrophysics Data System (ADS)

    Hynes, R. I.; Robinson, E. L.; Morales, J.

    2015-06-01

    We obtained a second time-resolved observation of the outbursting black hole X-ray transient V404 Cyg (ATEL #7677 and references therein) for about two hours on 2015 June 19.35-19.44 UT using the Argos photometer on the 2.1m Otto Struve Telescope at McDonald Observatory.

  14. The void galaxy survey: photometry, structure and identity of void galaxies

    NASA Astrophysics Data System (ADS)

    Beygu, B.; Peletier, R. F.; Hulst, J. M. van der; Jarrett, T. H.; Kreckel, K.; Weygaert, R. van de; van Gorkom, J. H.; Aragon-Calvo, M. A.

    2017-01-01

    We analyse photometry from deep B-band images of 59 void galaxies in the Void Galaxy Survey (VGS), together with their near-infrared 3.6 μm and 4.5 μm Spitzer photometry. The VGS galaxies constitute a sample of void galaxies that were selected by a geometric-topological procedure from the Sloan Digital Sky Survey Data Release 7 data release, and which populate the deep interior of voids. Our void galaxies span a range of absolute B-magnitude from MB = -15.5 to -20, while at the 3.6 μm band their magnitudes range from M3.6 = -18 to -24. Their B-[3.6] colour and structural parameters indicate these are star-forming galaxies. A good reflection of the old stellar population, the near-infrared band photometry also provide a robust estimate of the stellar mass, which for the VGS galaxies we confirm to be smaller than 3 × 1010 M⊙. In terms of the structural parameters and morphology, our findings align with other studies in that our VGS galaxy sample consists mostly of small late-type galaxies. Most of them are similar to Sd-Sm galaxies, although a few are irregularly shaped galaxies. The sample even includes two early-type galaxies, one of which is an AGN. Their Sérsic indices are nearly all smaller than n = 2 in both bands and they also have small half-light radii. In all, we conclude that the principal impact of the void environment on the galaxies populating them mostly concerns their low stellar mass and small size.

  15. VizieR Online Data Catalog: Multiwavelength photometry of 34 galaxies (Rowlands+, 2014)

    NASA Astrophysics Data System (ADS)

    Rowlands, K.; Dunne, L.; Dye, S.; Aragon-Salamanca, A.; Maddox, S.; da Cunha, E.; Smith, D. J. B.; Bourne, N.; Eales, S.; Gomez, H. L.; Smail, I.; Alpaslan, M.; Clark, C. J. R.; Driver, S.; Ibar, E.; Ivison, R. J.; Robotham, A.; Smith, M. W. L.; Valiante, E.

    2014-03-01

    Photometry for 34 submillimetre galaxies (including 5 galaxies with poor quality SED fits rejected from the final sample) utilised in the paper from the compilation in Magnelli et al (2012A&A...539A.155M, hereafter M12), which were taken from blank field (sub)millimetre surveys (850-1200um) which have robust counterparts identified with deep radio, interferometric submillimetre and/or mid-infrared imaging. In GOODS-N all photometry shortwards of 3um is described in Berta et al. (2010A&A...518L..30B, 2011A&A...532A..49B) and includes PSF-matched photometry from HST ACS bviz (version 1.0), FLAMINGOS JHK, IRAC 3.6, 4.5, 5.8, 8.0um was obtained with the ConvPhot code and spectroscopic redshifts and U-band magnitudes from Barger et al. (2008, Cat. J/ApJ/689/687). Deep CFHT WirCAM K_s band photometry was taken from Wang et al. (2010, Cat. J/ApJS/187/251). We refer the reader to http://www2011.mpe.mpg.de/ir/Research/PEP/publicdatareleases.php?lang=en for details, but briefly, magnitudes with value +99.99 are non-detections. ConvPhot-derived magnitudes are negative if they are fainter than the 1-sigma noise level. In this case the absolute value of the magnitude (with a small correction to galactic extinction) corresponds to half their flux and their magnitude uncertainty is equal to 0.7526mag. The U-band magnitudes from Barger et al. (2008, Cat. J/ApJ/689/687) are -99.99 if a source was not matched. In some cases magnitudes are negative and not -99.99, see Barger et al (2008, Cat. J/ApJ/689/687) for details. WIRCam Ks magnitudes are -99.99 if an object was not matched. The 70um MIPS data in GOODS-N are from Magnelli et al. (2011, Cat. J/A+A/528/A35), negative flux values indicate an upper limit, with the absolute flux value equal to the 5σ upper limit computed from the 70um residual map. We list the uncertainties from both the residual map and Monte-Carlo simulations which includes an additional statistical contribution from confusion noise, see Magnelli et al. (2011

  16. Three-dimensional optical micro-angiography maps directional blood perfusion deep within microcirculation tissue beds in vivo

    NASA Astrophysics Data System (ADS)

    Wang, Ruikang K.

    2007-12-01

    Optical micro-angiography (OMAG) is a recently developed method of imaging localized blood perfusion at capillary level resolution within microcirculatory beds. This paper reports that the OMAG is capable of directional blood perfusion mapping in vivo. This is achieved simply by translating the mirror located in the reference arm back and forth while 3D imaging is performed. The mirror which moves toward the incident beam gives the blood perfusion that flows away from the beam direction and vice versa. The approach is experimentally demonstrated by imaging of a flow phantom and then cerebro-vascular perfusion of a live mouse with cranium intact.

  17. Techniques for Automated Single-Star Photometry

    NASA Technical Reports Server (NTRS)

    Henry, Gregory W.

    2001-01-01

    Tennessee State University operates several automatic photoelectric telescopes (APTs) located at Fairborn Observatory in the Patagonia Mountains of southern Arizona. The APTs are dedicated to photometric monitoring programs that would be expensive and difficult to accomplish without the advantages of automation. I review the operation of two of the telescopes (a 0.75- and 0.80-meter (m) APT) and the quality-control techniques that result in the routine acquisition of single-star differential photometry with a precision of 0.001 mag for single observations and 0.0001 - 0.0002 mag for seasonal means. I also illustrate the capabilities of the APTS with sample results from a program to measure luminosity cycles in sun-like stars and a related program to search for the signatures of extrasolar planets around these stars.

  18. TERMS PHOTOMETRY OF KNOWN TRANSITING EXOPLANETS

    SciTech Connect

    Dragomir, Diana; Kane, Stephen R.; Ciardi, David R.; Gelino, Dawn M.; Payne, Alan; Ramirez, Solange V.; Von Braun, Kaspar; Wyatt, Pamela; Pilyavsky, Genady; Mahadevan, Suvrath; Wright, Jason T.; Zachary Gazak, J.; Rabus, Markus

    2011-10-15

    The Transit Ephemeris Refinement and Monitoring Survey conducts radial velocity and photometric monitoring of known exoplanets in order to refine planetary orbits and predictions of possible transit times. This effort is primarily directed toward planets not known to transit, but a small sample of our targets consists of known transiting systems. Here we present precision photometry for six WASP (Wide Angle Search for Planets) planets acquired during their transit windows. We perform a Markov Chain Monte Carlo analysis for each planet and combine these data with previous measurements to redetermine the period and ephemerides for these planets. These observations provide recent mid-transit times which are useful for scheduling future observations. Our results improve the ephemerides of WASP-4b, WASP-5b, and WASP-6b and reduce the uncertainties on the mid-transit time for WASP-29b. We also confirm the orbital, stellar, and planetary parameters of all six systems.

  19. Generalized Stellar Parametrizer with Gaia Photometry Data

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Bailer-Jones, Coryn A. L.

    GSP-Phot (Generalized Stellar Parametrizer—Photometry) is a software package in the Gaia Astrophysical parameters processing chain (Apsis) which estimates the astrophysical parameters of all stars in the Gaia catalogue. The inputs of GSP-Phot are the low-resolution spectra from the Gaia photometers as well as parallaxes, while the outputs consist of effective temperatures (T eff), extinction parameters (A 0), metallicities ([Fe/H] and surface gravities (logg). Three algorithms are developed in GSP-Phot: (a) support vector machine regression (SVR), a pattern recognition method; (b) ILIUM, a forward model based on discrete synthetic parameter grid; and (c) q-method, a Bayesian method which combines a forward model with parallaxes and the Hertzsprung-Russell diagram (HRD) as a prior. The performance of the three algorithms is investigated for a range of spectral types with arbitrary apparent magnitudes.

  20. Photoelectric photometry of comet Kohoutek (1973f)

    NASA Technical Reports Server (NTRS)

    Kohoutek, L.

    1976-01-01

    Comet Kohoutek was observed with the 50 cm (f/15) reflecting telescope of the European Southern Observatory, La Silla, Chile, on fourteen nights between January 16 and 30, when the heliocentric and geocentric distances of the comet were r=0.66 - 1.00 A.U. and delta=0.81 - 0.96 A.U., respectively. The 40 inch and 80 inch diaphragms were used for the photometry of the cometary head in the UBV system and with six interference filters. The atmospheric conditions were good but the accuracy of observations was low due to large extinction and twilight. The mean error of one measurement of log F in all but Na 5893 A filters can be estimated at plus or minus 0.02, whereas the accuracy through the Na filter was substantially lower.

  1. CCD time-resolved photometry of faint cataclysmic variables. II

    SciTech Connect

    Szkody, P.; Howell, S.B.; Mateo, M.; Kreidl, T.J. Planetary Science Institute, Tucson, AZ Mount Wilson and Las Campanas Observatories, Pasadena, CA Lowell Observatory, Flagstaff, AZ )

    1989-10-01

    Time-resolved optical broad-band light curves obtained from differential photometry on sequential CCD frames of the known or suspected cataclysmic variable FO And, EH Aqr, WX Cet, XX Cet, AL Com, V503 Cyg, AH Eri, CP Eri, IR Gem, RW UMi, PG0134+070, and US 3215 are presented. The analysis of the light curves with coverage of greater than 2 hrs shows repeatable periodicity in five objects. PG0134+070 exhibits eclipses of 1.3-1.8 mag depth with a period of 313 min. V503 Cyg has a 0.7-1.0 mag peak-to-peak modulation with a period of 109 min. IR Gem shows a large modulation at the orbital period of 99 min, and comparison with previous data indicates that this modulation may have an amplitude dependent on outburst phase. AH Eri reveals a 0.1-0.3 mag modulation, at a period of 42 min. Better time-resolved data on AL Com confirm the 0.4-mag variation reported by Howell and Szkody (1988) at a period of 42 min. These latter two short periods likely indicate magnetic systems. There is also some evidence of periodicity in RW UMi and WX Cet which must be confirmed with further data. 25 refs.

  2. GASPS Photometry of the Tucana-Horologium Association

    NASA Technical Reports Server (NTRS)

    Roberge, Donaldson J.; Roberge, Aki

    2010-01-01

    The GASPS Open Time Key Programme on Herschel represents a new opportunity to sensitively probe protoplanetary and debris disks at far-IR wavelengths. We present preliminary PACS 70 and 160 micron photometry of eighteen stars in the 30 Myr-old Tucana-Horologium association. Of these eighteen, eight were detected in the 70 micron band. Four of these eight were also detected in the 160 micron band. We constructed SEDs for these systems using optical data from Hipparcos (B and V), near-IR data from 2MASS (J, H, and K), mid-IR data from IRAS and Spitzer MIPS (12 and 24 microns, respectively), and the new far-IR data from PACS. For the stars showing IR excess emission, we fit simple single-temperature blackbody curves to the IR excess in order to determine the rough dust abundances and temperatures. Dust observations at these wavelengths will also be important for comparison with upcoming Herschel PACS spectra that will search for gas in the disks. Our goal is to determine or limit the ever-allusive gas-to-dust ratio for these disk systems.

  3. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

    PubMed Central

    Villiger, Martin; Lorenser, Dirk; McLaughlin, Robert A.; Quirk, Bryden C.; Kirk, Rodney W.; Bouma, Brett E.; Sampson, David D.

    2016-01-01

    Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign tissue. Here, we performed polarization-sensitive optical coherence tomography through miniature imaging needles and developed an algorithm to efficiently reconstruct images of the depth-resolved tissue birefringence free of artefacts. First ex vivo imaging of breast tumour samples revealed excellent contrast between lowly birefringent malignant regions, and stromal tissue, which is rich in oriented collagen and exhibits higher birefringence, as confirmed with co-located histology. The ability to clearly differentiate between tumour and uninvolved stroma based on intrinsic contrast could prove decisive for the intraoperative assessment of tumour margins. PMID:27364229

  4. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

    NASA Astrophysics Data System (ADS)

    Villiger, Martin; Lorenser, Dirk; McLaughlin, Robert A.; Quirk, Bryden C.; Kirk, Rodney W.; Bouma, Brett E.; Sampson, David D.

    2016-07-01

    Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign tissue. Here, we performed polarization-sensitive optical coherence tomography through miniature imaging needles and developed an algorithm to efficiently reconstruct images of the depth-resolved tissue birefringence free of artefacts. First ex vivo imaging of breast tumour samples revealed excellent contrast between lowly birefringent malignant regions, and stromal tissue, which is rich in oriented collagen and exhibits higher birefringence, as confirmed with co-located histology. The ability to clearly differentiate between tumour and uninvolved stroma based on intrinsic contrast could prove decisive for the intraoperative assessment of tumour margins.

  5. AGN on the color-magnitude diagram: Results from a Deep Medium Band Survey with the Subaru Telescope in the MUSYC-ECDFS Region

    NASA Astrophysics Data System (ADS)

    Cardamone, Carolin; Urry, C. Megan; van Dokkum, P.; Schawinski, Kevin; Gawiser, E.; Brammer, G.; Taylor, N.; Treister, E.; Taniguchi, Y.; Virani, S.

    2009-09-01

    We investigate the host galaxy colors of X-ray detected AGN in the Extended Chandra Deep Field South.We have conducted deep medium-band imaging with the Subaru telescope, in 18 filters from 427 nm to 856 nm, of the MUSYC survey field. We detect 80,000 galaxies to equivalent magnitude R 27 mag, of which approximately 1,000 are X-ray-detected AGN observed with Chandra and XMM. Combining the Subaru data with optical, IR data and IRAC photometry we obtain photometric redshifts using EAZY, a fast public photometric redshift code, in the range 0

  6. RESOLVE Survey Photometry and Volume-limited Calibration of the Photometric Gas Fractions Technique

    NASA Astrophysics Data System (ADS)

    Eckert, Kathleen D.; Kannappan, Sheila J.; Stark, David V.; Moffett, Amanda J.; Norris, Mark A.; Snyder, Elaine M.; Hoversten, Erik A.

    2015-09-01

    We present custom-processed ultraviolet, optical, and near-infrared photometry for the REsolved Spectroscopy of a Local VolumE (RESOLVE) survey, a volume-limited census of stellar, gas, and dynamical mass within two subvolumes of the nearby universe (RESOLVE-A and RESOLVE-B). RESOLVE is complete down to baryonic mass ˜ {10}9.1-9.3 {M}⊙ , probing the upper end of the dwarf galaxy regime. In contrast to standard pipeline photometry (e.g., SDSS), our photometry uses optimal background subtraction, avoids suppressing color gradients, and employs multiple flux extrapolation routines to estimate systematic errors. With these improvements, we measure brighter magnitudes, larger radii, bluer colors, and a real increase in scatter around the red sequence. Combining stellar mass estimates based on our optimized photometry with the nearly complete H i mass census for RESOLVE-A, we create new z = 0 volume-limited calibrations of the photometric gas fractions (PGF) technique, which predicts gas-to-stellar mass ratios (G/S) from galaxy colors and optional additional parameters. We analyze G/S-color residuals versus potential third parameters, finding that axial ratio is the best independent and physically meaningful third parameter. We define a “modified color” from planar fits to G/S as a function of both color and axial ratio. In the complete galaxy population, upper limits on G/S bias linear and planar fits. We therefore model the entire PGF probability density field, enabling iterative statistical modeling of upper limits and prediction of full G/S probability distributions for individual galaxies. These distributions have two-component structure in the red color regime. Finally, we use the RESOLVE-B 21 cm census to test several PGF calibrations, finding that most systematically under- or overestimate gas masses, but the full probability density method performs well.

  7. Dual-Pulse Pulse Position Modulation (DPPM) for Deep-Space Optical Communications: Performance and Practicality Analysis

    NASA Technical Reports Server (NTRS)

    Li, Jing; Hylton, Alan; Budinger, James; Nappier, Jennifer; Downey, Joseph; Raible, Daniel

    2012-01-01

    Due to its simplicity and robustness against wavefront distortion, pulse position modulation (PPM) with photon counting detector has been seriously considered for long-haul optical wireless systems. This paper evaluates the dual-pulse case and compares it with the conventional single-pulse case. Analytical expressions for symbol error rate and bit error rate are first derived and numerically evaluated, for the strong, negative-exponential turbulent atmosphere; and bandwidth efficiency and throughput are subsequently assessed. It is shown that, under a set of practical constraints including pulse width and pulse repetition frequency (PRF), dual-pulse PPM enables a better channel utilization and hence a higher throughput than it single-pulse counterpart. This result is new and different from the previous idealistic studies that showed multi-pulse PPM provided no essential information-theoretic gains than single-pulse PPM.

  8. Detection Performance of Upgraded "Polished Panel" Optical Receiver Concept on the Deep-Space Network's 34 Meter Research Antenna

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    2012-01-01

    Initial optical communications experiments with a Vertex polished aluminum panel have been described. The polished panel was mounted on the main reflector of the DSN's research antenna at DSS-13. The PSF was recorded via remotely controlled digital camera mounted on the subreflector structure. Initial PSF generated by Jupiter showed significant tilt error and some mechanical deformation. After upgrades, the PSF improved significantly, leading to much better concentration of light. Communications performance of the initial and upgraded panel structure were compared. After the upgrades, simulated PPM symbol error probability decreased by six orders of magnitude. Work is continuing to demonstrate closed-loop tracking of sources from zenith to horizon, and better characterize communications performance in realistic daytime background environments.

  9. Deep-sea spherules from Pacific clay - Mass distribution and influx rate. [extraterrestrial origins from optical and electron microscopy

    NASA Technical Reports Server (NTRS)

    Murrell, M. T.; Davis, P. A., Jr.; Nishiizumi, K.; Millard, H. T., Jr.

    1980-01-01

    From 411 kg of Pacific clay, 22 mg of stony spherules and 50 mg of iron spherules larger than 150 microns were concentrated. The extraterrestrial origin of these particles was evaluated with the aid of optical and electron microscopy and atomic absorption elemental analysis. An expression for the integral number of stony particles from this sediment in the mass range 20-300 micrograms was derived. The world-wide influx rate of stony particles in the mass range which survive atmospheric heating and ocean sediment storage is calculated to be 90 tons/yr. The relative contributions of ablation debris vs fused interplanetary dust to the influx of stony spherules is discussed, but no conclusions could be made.

  10. Deep sequencing unearths nuclear mitochondrial sequences under Leber's hereditary optic neuropathy-associated false heteroplasmic mitochondrial DNA variants.

    PubMed

    Petruzzella, Vittoria; Carrozzo, Rosalba; Calabrese, Claudia; Dell'Aglio, Rosa; Trentadue, Raffaella; Piredda, Roberta; Artuso, Lucia; Rizza, Teresa; Bianchi, Marzia; Porcelli, Anna Maria; Guerriero, Silvana; Gasparre, Giuseppe; Attimonelli, Marcella

    2012-09-01

    Leber's hereditary optic neuropathy (LHON) is associated with mitochondrial DNA (mtDNA) ND mutations that are mostly homoplasmic. However, these mutations are not sufficient to explain the peculiar features of penetrance and the tissue-specific expression of the disease and are believed to be causative in association with unknown environmental or other genetic factors. Discerning between clear-cut pathogenetic variants, such as those that appear to be heteroplasmic, and less penetrant variants, such as the homoplasmic, remains a challenging issue that we have addressed here using next-generation sequencing approach. We set up a protocol to quantify MTND5 heteroplasmy levels in a family in which the proband manifests a LHON phenotype. Furthermore, to study this mtDNA haplotype, we applied the cybridization protocol. The results demonstrate that the mutations are mostly homoplasmic, whereas the suspected heteroplasmic feature of the observed mutations is due to the co-amplification of Nuclear mitochondrial Sequences.

  11. VizieR Online Data Catalog: Photometry of nova LMC 2012 (Schwarz+, 2015)

    NASA Astrophysics Data System (ADS)

    Schwarz, G. J.; Shore, S. N.; Page, K. L.; Osborne, J. P.; Beardmore, A. P.; Walter, F. M.; Bode, M. F.; Drake, J. J.; Ness, J.-U.; Starrfield, S.; van Rossum, D. R.; Woodward, C. E.

    2015-03-01

    Nova LMC 2012 was discovered on March 26.397 UT (MJD56012.897) at a visual magnitude of 10.7 (Seach et al., 2012CBET.3071....1S). After discovery, LMC 2012 was observed by a number of different facilities at a variety of wavelengths. The discovery date is taken as day zero and the shorthand "Dn," where "n" is the number of days after day zero, is used here. Swift is a revolutionary facility for studying novae (see Schwarz et al. 2011, cat. J/ApJS/197/31, for details). Its three instruments cover the γ-ray (BAT), X-ray (XRT), plus UV and optical (UVOT) bandpasses. Swift obtained 74 uvm2 band (λeff=2246Å, FWHM=498Å) observations of LMC 2012 with the UVOT instrument from D1.2 until D671. There were also 12 uvw2 band (λeff=1928Å, FWHM=657Å) and nine uvw1 band (λeff=2600Å, FWHM=693Å) observations which were only obtained early on D1.2 and later during the observations after D300. The UVOT photometry is provided in Table2. LMC 2012 was extensively observed photometrically between D0.6 and D635 with the Small & Moderate Aperture Research Telescope System (SMARTS) at Cerro Tololo (see Walter et al., 2012PASP..124.1057W, for details). We obtained 250 photometric observations in BVRI/JHK from SMARTS. The optical photometry is supplemented with 54 early time CCD BVRI observations from the American Association of Variable Star Observers (AAVSO). The optical and near-infrared photometry is also given in Table2. (2 data files).

  12. Automated surface photometry for the Coma Cluster galaxies: The catalog

    NASA Technical Reports Server (NTRS)

    Doi, M.; Fukugita, M.; Okamura, S.; Tarusawa, K.

    1995-01-01

    A homogeneous photometry catalog is presented for 450 galaxies with B(sub 25.5) less than or equal to 16 mag located in the 9.8 deg x 9.8 deg region centered on the Coma Cluster. The catalog is based on photographic photometry using an automated surface photometry software for data reduction applied to B-band Schmidt plates. The catalog provides accurate positions, isophotal and total magnitudes, major and minor axes, and a few other photometric parameters including rudimentary morphology (early of late type).

  13. Intermediate-band photometry of faint standard stars

    NASA Technical Reports Server (NTRS)

    Dawson, D. W.

    1976-01-01

    The David Dunlap Observatory system uses six intermediate-band filters whose central wavelengths were chosen to cover important features in the spectrum of a late-type star. Calibrations of the color indices with physical parameters, allow one to estimate T sub eff, log g, Fe/H, M sub v and reddening directly from the photometry. Although a number of standards lists exist, only a small fraction of the stars is fainter than V=6. It is desirable to add to the numbers of faint standards. Results are presented of photometry of sixteen stars obtained during a program of variable-star photometry at Blue Mesa Observatory.

  14. SWIFT/UVOT PHOTOMETRY OF THE PLANETARY NEBULA WeBo 1: UNMASKING A FAINT HOT COMPANION STAR

    SciTech Connect

    Siegel, Michael H.; Hoversten, Erik; Stark, Michele; Bond, Howard E.; Breeveld, Alice A. E-mail: hoversten@swift.psu.edu E-mail: bond@stsci.edu

    2012-08-15

    We present an analysis of over 150 ks of data on the planetary nebula WeBo 1 (PN G135.6+01.0) obtained with the Swift Ultraviolet Optical Telescope (UVOT). The central object of this nebula has previously been described as a late-type K giant barium star with a possible hot companion, most likely a young pre-white dwarf. UVOT photometry shows that while the optical photometry is consistent with a large cool object, the near-ultraviolet (NUV) photometry shows far more UV flux than could be produced by any late-type object. Using model stellar atmospheres and a comparison to UVOT photometry for the pre-white dwarf PG 1159-035, we find that the companion has a temperature of at least 40,000 K and a radius of, at most, 0.056 R{sub Sun }. While the temperature and radius are consistent with a hot compact stellar remnant, they are lower and larger, respectively, than expected for a typical young pre-white dwarf. This likely indicates a deficiency in the assumed UV extinction curve. We find that higher temperatures more consistent with expectations for a pre-white dwarf can be derived if the foreground dust has a strong 'blue bump' at 2175 A and a lower R{sub V}. Our results demonstrate the ability of Swift to both uncover and characterize hot hidden companion stars and to constrain the UV extinction properties of foreground dust based solely on UVOT photometry.

  15. Optical microspectrometer

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2004-05-25

    An optical microspectrometer comprises a grism to disperse the spectra in a line object. A single optical microspectrometer can be used to sequentially scan a planar object, such as a dye-tagged microchip. Because the optical microspectrometer is very compact, multiple optical microspectrometers can be arrayed to provide simultaneous readout across the width of the planar object The optical microspectrometer can be fabricated with lithographic process, such as deep X-ray lithography (DXRL), with as few as two perpendicular exposures.

  16. Photometry and Kinematics of Ultracool Dwarfs in the Pan-STARRS 3pi Survey

    NASA Astrophysics Data System (ADS)

    Best, William M. J.; Magnier, Eugene A.; Liu, Michael C.; Aller, Kimberly Mei; Zhang, Zhoujian

    2017-01-01

    The Pan-STARRS 1 3π Survey (PS1) has observed the entire sky north of -30° in five optical bands (grizy) over an average of 12 epochs spanning four years, generating an exceptional new resource for discovering and characterizing ultracool dwarfs. We present our analysis of the PS1 photometry and proper motions of over 2,000 M, L, and T dwarfs, building a comprehensive picture of the local ultracool population. We highlight ultracool binaries, subdwarfs, and young objects in our analysis, identifying features that distinguish them from the field population.

  17. Determination of water pollution by the oil products through UV photometry.

    PubMed

    Winkler, Igor; Agapova, Nataliya

    2010-09-01

    Results of UV photometry of water/gasoline systems are reported. It was found that this system can be characterized with an analytical light absorption peak with maximum at 260 nm. A calibrating diagram for optical density vs. gasoline content has been built for this peak and concentration limits of the gasoline compounds' solubility in water were found. The peak pattern and its position indicate that 1,3,5-trimethylbenzene and/or its closest homologs can be those gasoline compounds, which reveal themselves through the UV light absorption peak.

  18. Color Gradients and Stellar Population Gradients of Early-type Galaxies at z 2 in the Hubble Ultra Deep Field

    NASA Astrophysics Data System (ADS)

    Guo, Yicheng; Giavalisco, M.; Cassata, P.; Koekemoer, A.

    2011-01-01

    We report the detection of color gradients in massive (stellar mass M>1010 Msun) galaxies with low specific star formation rate (SSFR<10-11/yr) at redshift z 2. The galaxies are selected by means of SED fitting to spectral population synthesis models using the Great Observatories Origins Deep Survey (GOODS) broad--band photometry, which spans the optical, near--IR and mid--IR windows, augmented by recent ultra--deep near--IR images obtained with HST WFC3. The estimated stellar mass and SSFR would place these galaxies among today's Hubble early types, while their rest--frame optical morphology, as shown by the WFC3 images, is consistent with that of spheroidal systems. The inner regions of these galaxies are found to have redder rest UV--optical colors than their outer parts. The slope of the color gradient has no obvious dependence on the redshift and stellar mass of the galaxies. It does depend, however, on the overall dust obscuration and rest-frame U-V color of the galaxies mildly, with more obscured or redder galaxies having steeper color gradient. The slope of the color gradient is generally steeper than that of local early-type galaxies. We find that the gradient of a single parameter (age, extinction or metallicity) cannot fully explain the observed color gradient. To study the physical implications of these color gradients, we fit spatially resolved HST seven--bands photometry from ACS and WFC3 images (BVizYJH) in concentric shells across the light profile of each galaxies, sampling the color gradients. Regardless of the assumed metallicity gradient, the redder inner regions always have slightly higher dust obscuration than the bluer outer regions, implying that a dust gradient may partly contribute to the observed color gradients. Because of the age--metallicity degeneracy, the derived age gradient is coupled with the assumed metallicity gradient. We discuss the plausibility and implication of each derived age gradient.

  19. Strengthening the open cluster distance scale via VVV photometry

    NASA Astrophysics Data System (ADS)

    Majaess, D.; Turner, D.; Moni Bidin, C.; Geisler, D.; Borissova, J.; Minniti, D.; Bonatto, C.; Gieren, W.; Carraro, G.; Kurtev, R.; Mauro, F.; Chené, A.-N.; Forbes, D.; Lucas, P.; Dékány, I.; Saito, R. K.; Soto, M.

    2012-01-01

    Approximately 14% of known Galactic open clusters possess absolute errors ≤ 20% as evaluated from n ≥ 3 independent distance estimates, and the statistics for age estimates are markedly worse. That impedes such diverse efforts as calibrating standard candles and constraining masses for substellar companions. New data from the VVV survey may be employed to establish precise cluster distances with comparatively reduced uncertainties ( ≤ 10%). This is illustrated by deriving parameters for Pismis 19 and NGC 4349, two pertinent open clusters which hitherto feature sizable uncertainties (60%). Fundamental parameters determined for Pismis 19 from new VVV JHKs photometry are d = 2.40 ± 0.15 kpc, ⟨EJ - H⟩ = 0.34 ± 0.04, and log τ = 9.05 ± 0.10, whereas for NGC 4349 the analysis yielded d = 1.63 ± 0.13 kpc, EJ - H = 0.09 ± 0.02, log τ = 8.55 ± 0.10. The results exhibit a significant ( ≥ 5 × ) reduction in uncertainties, and indicate that: i) existing parameters for the substellar object NGC 4349 127b require revision, in part because the new cluster parameters imply that the host is 20% less-massive (ℳ∗/ℳ⊙ ~ 3.1); ii) R Cru is not a member of NGC 4349 and should be excluded from period-Wesenheit calibrations that anchor the distance scale; iii) and results for Pismis 19 underscore the advantages gleaned from employing deep VVV JHKs data to examine obscured (AV ~ 4) and differentially reddened intermediate-age clusters. Based on observations taken within the ESO VISTA Public Survey VVV, Programme ID 179.B-2002.

  20. THE EXTENDED CHANDRA DEEP FIELD-SOUTH SURVEY: OPTICAL SPECTROSCOPY OF FAINT X-RAY SOURCES WITH THE VLT AND KECK

    SciTech Connect

    Silverman, J. D.; Mainieri, V.; Rosati, P.; Salvato, M.; Hasinger, G.; Bergeron, J.; Capak, P.; Szokoly, G.; Gilli, R.; Tozzi, P.; Vignali, C.; Alexander, D. M.; Brandt, W. N.; Luo, B.; Rafferty, D.; Xue, Y. Q.; Lehmer, B. D.; Bauer, F. E.

    2010-11-15

    We present the results of a program to acquire high-quality optical spectra of X-ray sources detected in the Extended-Chandra Deep Field-South (E-CDF-S) and its central 2 Ms area. New spectroscopic redshifts, up to z = 4, are measured for 283 counterparts to Chandra sources with deep exposures (t {approx} 2-9 hr per pointing) using multi-slit facilities on both VLT (VIMOS) and Keck (DEIMOS), thus bringing the total number of spectroscopically identified X-ray sources to over 500 in this survey field. Since our new spectroscopic identifications are mainly associated with X-ray sources in the shallower 250 ks coverage, we provide a comprehensive catalog of X-ray sources detected in the E-CDF-S including the optical and near-infrared counterparts, determined by a likelihood routine, and redshifts (both spectroscopic and photometric), that incorporate published spectroscopic catalogs, thus resulting in a final sample with a high fraction (80%) of X-ray sources having secure identifications. We demonstrate the remarkable coverage of the luminosity-redshift plane now accessible from our data while emphasizing the detection of active galactic nuclei (AGNs) that contribute to the faint end of the luminosity function (L {sub 0.5-8keV} {approx} 10{sup 43}-10{sup 44} erg s{sup -1}) at 1.5 {approx}< z {approx}< 3 including those with and without broad emission lines. Our redshift catalog includes 17 type-2 QSOs at 1 {approx}< z {approx}< 3.5 that significantly increases such samples (2x). Based on our deepest (9 hr) VLT/VIMOS observation, we identify 'elusive' optically faint galaxies (R {sub mag} {approx} 25) at z {approx} 2-3 based upon the detection of interstellar absorption lines (e.g., O II+Si IV, C II], C IV); we highlight one such case, an absorption-line galaxy at z = 3.208 having no obvious signs of an AGN in its optical spectrum. In addition, we determine accurate distances to eight galaxy groups with extended X-ray emission detected both by Chandra and XMM

  1. Optical properties of natural dissolved organic matter (DOM) in aquatic ecosystems: Applications in ecosystem studies from headwater streams to the deep ocean. (Invited)

    NASA Astrophysics Data System (ADS)

    Jaffe, R.

    2010-12-01

    The study of natural dissolved organic material (DOM) contributes to the better understanding of ecosystem function as the carbon flux between environmental compartments represents an important linkage between terrestrial and aquatic ecosystems. Within freshwater and marine ecosystems, DOM typically represents the largest pool of detrital organic carbon and greatly exceeds the organic carbon present in living biomass. Thus, the sources and fate of DOM are important terms in carbon budgets. DOM can also influence ecosystem function by controlling microbial food webs, act as a means of nutrient transport, buffer pH and influence toxicity and bioavailability of pollutants, among others. DOM composition influences its ‘quality’ and thus its photo- and bio-reactivity, both of which exert a strong control of the diagenetic reworking of this carbon pool. However, the molecular composition of DOM is highly complex and diverse, and its characterization is a serious challenge to analytical chemists. In recent years, several novel analytical approaches to the characterization of DOM have evolved, including those that are highly structure specific and others that provide information on broader molecular characteristics. Whilst the former are usually expensive and time consuming, the latter, often based on optical properties measurements, feature high sample throughput at a reduced cost but at the expense of structural specificity. While both approaches are complementary under ideal conditions, the latter are best suited for studies involving large spatial and temporal scales. The analysis of DOM optical properties, in particular excitation emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC), has emerged as a practical tool for the broad characterization of DOM quality. This presentation will provide examples for the application of EEM-PARAFAC in assessing environmental dynamics of DOM on both spatial and temporal scales, and in both

  2. In vivo optical microprobe imaging for intracellular Ca2+ dynamics in response to dopaminergic signaling in deep brain evoked by cocaine

    NASA Astrophysics Data System (ADS)

    Luo, Zhongchi; Pan, Yingtian; Du, Congwu

    2012-02-01

    Ca2+ plays a vital role as second messenger in signal transduction and the intracellular Ca2+ ([Ca2+]i) change is an important indicator of neuronal activity in the brain, including both cortical and subcortical brain regions. Due to the highly scattering and absorption of brain tissue, it is challenging to optically access the deep brain regions (e.g., striatum at >3mm under the brain surface) and image [Ca2+]i changes with cellular resolutions. Here, we present two micro-probe approaches (i.e., microlens, and micro-prism) integrated with a fluorescence microscope modified to permit imaging of neuronal [Ca2+]i signaling in the striatum using a calcium indicator Rhod2(AM). While a micro-prism probe provides a larger field of view to image neuronal network from cortex to striatum, a microlens probe enables us to track [Ca2+]i dynamic change in individual neurons within the brain. Both techniques are validated by imaging neuronal [Ca2+]i changes in transgenic mice with dopamine receptors (D1R, D2R) expressing EGFP. Our results show that micro-prism images can map the distribution of D1R- and D2R-expressing neurons in various brain regions and characterize their different mean [Ca2+]i changes induced by an intervention (e.g., cocaine administration, 8mg/kg., i.p). In addition, microlens images can characterize the different [Ca2+]i dynamics of D1 and D2 neurons in response to cocaine, including new mechanisms of these two types of neurons in striatum. These findings highlight the power of the optical micro-probe imaging for dissecting the complex cellular and molecular insights of cocaine in vivo.

  3. Detection of Extrasolar Planets by Transit Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William; Koch, David; Webster, Larry; Dunham, Edward; Witteborn, Fred; Jenkins, Jon; Caldwell, Douglas; Showen, Robert; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    A knowledge of other planetary systems that includes information on the number, size, mass, and spacing of the planets around a variety of star types is needed to deepen our understanding of planetary system formation and processes that give rise to their final configurations. Recent discoveries show that many planetary systems are quite different from the solar system in that they often possess giant planets in short period orbits. The inferred evolution of these planets and their orbital characteristics imply the absence of Earth-like planets near the habitable zone. Information on the properties of the giant-inner planets is now being obtained by both the Doppler velocity and the transit photometry techniques. The combination of the two techniques provides the mass, size, and density of the planets. For the planet orbiting star HD209458, transit photometry provided the first independent confirmation and measurement of the diameter of an extrasolar planet. The observations indicate a planet 1.27 the diameter of Jupiter with 0.63 of its mass (Charbonneau et al. 1999). The results are in excellent agreement with the theory of planetary atmospheres for a planet of the indicated mass and distance from a solar-like star. The observation of the November 23, 1999 transit of that planet made by the Ames Vulcan photometer at Lick Observatory is presented. In the future, the combination of the two techniques will greatly increase the number of discoveries and the richness of the science yield. Small rocky planets at orbital distances from 0.9 to 1.2 AU are more likely to harbor life than the gas giant planets that are now being discovered. However, new technology is needed to find smaller, Earth-like planets, which are about three hundred times less massive than Jupiter-like planets. The Kepler project is a space craft mission designed to discover hundreds of Earth-size planets in and near the habitable zone around a wide variety of stars. To demonstrate that the

  4. HST Photometry of Uranus 1994-2015

    NASA Astrophysics Data System (ADS)

    Karkoschka, Erich

    2016-10-01

    Images of Uranus by the Hubble Space Telescope (HST) provide a useful tool in studying seasonal and other physical changes on Uranus. HST gives spatial resolution on the disk of Uranus, wide spectral coverage, temporal coverage over more than 20 years, and stable photometric properties. We selected 1368 images in 81 filters of four cameras between 240 and 1130 nm wavelength taken between August 1994 and October 2015.We started with analyzing the photometry of the whole disk of Uranus. We divided the total light of Uranus into the light from "quiet" Uranus and the light from active storms, which can contribute as much as 2.3 % to the total light, although their median contribution is only 0.14 %. The statistical analysis of the light from storms as function of wavelength and time gives clues about their temporal distribution and altitude distribution since different filters probe different altitudes.The photometry of quiet Uranus shows three main variations: a smooth seasonal variation, a small deviation from this on time scales of 1-2 years, and a small variation with phase angle. The latter variation is 0.15 % for each degree of phase angle between 0 and 3 degrees. This may be the first such measurement for Uranus. The deviations from the smooth curve are about 0.2 %, which is significant since most data otherwise fit to the 0.1 % level.The seasonal variation has the same shape at all wavelengths, except that the amplitude differs. The shape is roughly a parabola with a minimum brightness in 2009, two years after the equinox of Uranus. The amplitude is negligible at wavelengths probing high altitudes but goes up to a factor of 2.1 in wavelengths probing the 1-2 bar level. The seasonal variation is a combined effect of physical change in the atmosphere and the geometric change due to variable sub-solar and sub-Earth latitudes. The physical change is further divided into darkening of high southern latitudes and brightening of high northern latitudes. The

  5. L' AND M' Photometry Of Ultracool Dwarfs

    NASA Technical Reports Server (NTRS)

    Marley, M. S.; Tsvetanov, Z. I.; Vrba, F. J.; Henden, A. A.; Luginbuhl, C. B.

    2004-01-01

    We have compiled L' (3.4-4.1 microns) and M' (4.6- 4.8 microns) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory filter set. This compilation includes new L' measurements of eight L dwarfs and 13 T dwarfs and new M' measurements of seven L dwarfs, five T dwarfs, and the M1 dwarf Gl 229A. These new data increase by factors of 0. 6 and 1.6, respectively, the numbers of ultracool dwarfs T (sub eff) photometry, and trigonometric parallaxes are available, and we estimate these quantities for nine other dwarfs whose parallaxes and flux-calibrated spectra have been obtained. BC(SUB K) is a well-behaved function of near-infrared spectral type with a dispersion of approx. 0.1 mag for types M6-T5 it is significantly more scattered for types T5-T9. T (sub eff) declines steeply and monotonically for types M6-L7 and T4-T9, but it is nearly constant at approx. 1450 K for types L7-T4 with assumed ages of approx. 3 Gyr. This constant T(sub eff) is evidenced by nearly unchanging values of L'-M' between types L6 and T3. It also supports recent models that attribute the changing near-infrared luminosities and spectral features across the L-T transition to the rapid migration, disruption, and/or thinning of condensate clouds over a narrow range of T(sub eff). The L' and M' luminosities of early-T dwarfs do not exhibit the pronounced humps or inflections previously noted in l through K bands, but insufficient data exist for types L6-T5 to assert that M(Sub L') and M(sub M') are strictly monotonic within this range of typew. We compare the observed K, L', and M' luminosities of L and T dwarfs in our sample with those predicted by precipitation-cloud-free models for varying surface gravities and sedimentation efficiencies.

  6. Photometric calibration of NGS/POSS and ESO/SRC plates using the NOAO PDS measuring engine. I - Stellar photometry

    NASA Technical Reports Server (NTRS)

    Cutri, Roc M.; Low, Frank J.; Marvel, Kevin B.

    1992-01-01

    The PDS/Monet measuring engine at the National Optical Astronomy Observatory was used to obtain photometry of nearly 10,000 stars on the NGS/POSS and 2000 stars on the ESO/SRC Survey glass plates. These measurements have been used to show that global transformation functions exist that allow calibration of stellar photometry from any blue or red plate to equivalent Johnson B and Cousins R photoelectric magnitudes. The four transformation functions appropriate for the POSS O and E and ESO/SRC J and R plates were characterized, and it was found that, within the measurement uncertainties, they vary from plate to plate only by photometric zero-point offsets. A method is described to correct for the zero-point shifts and to obtain calibrated B and R photometry of stellar sources to an average accuracy of 0.3-0.4 mag within the range R between values of 8 and 19.5 for red plates in both surveys, B between values of 9 and 20.5 on POSS blue plates, and B between values of 10 and 20.5 on ESO/SRC blue plates. This calibration procedure makes it possible to obtain rapid photometry of very large numbers of stellar sources.

  7. WIYN Open Cluster Study: UBVRI Photometry of NGC 2158

    NASA Astrophysics Data System (ADS)

    Taverne, Luke T.; Steinhauer, Aaron J.; Deliyannis, Constantine P.

    2015-01-01

    We present WIYN 0.9m HDI UBVRI photometry of NGC 2158, a very rich, intermediate-aged, open cluster located near the galactic anti-center. We report derived values for the cluster age, distance, reddening.

  8. Comparison of galaxy clusters selected by weak-lensing, optical spectroscopy, and X-rays in the deep lens survey F2 field

    SciTech Connect

    Starikova, Svetlana; Jones, Christine; Forman, William R.; Vikhlinin, Alexey; Kurtz, Michael J.; Fabricant, Daniel G.; Murray, Stephen S.; Geller, Margaret J.; Dell'Antonio, Ian P.

    2014-05-10

    We compare galaxy clusters selected in Chandra and XMM-Newton X-ray observations of the 4 deg{sup 2} Deep Lens Survey (DLS) F2 field to the cluster samples previously selected in the same field from a sensitive weak-lensing shear map derived from the DLS and from a detailed galaxy redshift survey—the Smithsonian Hectospec Lensing Survey (SHELS). Our Chandra and XMM-Newton observations cover 1.6 deg{sup 2} of the DLS F2 field, including all 12 weak-lensing peaks above a signal-to-noise ratio of 3.5, along with 16 of the 20 SHELS clusters with published velocity dispersions >500 km s{sup –1}. We detect 26 extended X-ray sources in this area and confirm 23 of them as galaxy clusters using the optical imaging. Approximately 75% of clusters detected in either X-ray or spectroscopic surveys are found in both; these follow the previously established scaling relations between velocity dispersion, L {sub X}, and T {sub X}. A lower percentage, 60%, of clusters are in common between X-ray and DLS samples. With the exception of a high false-positive rate in the DLS weak-lensing search (5 out of 12 DLS candidates appear to be false), differences between the three cluster detection methods can be attributed primarily to observational uncertainties and intrinsic scatter between different observables and cluster mass.

  9. Discrete breather and soliton-mode collective excitations in Bose-Einstein condensates in a deep optical lattice with tunable three-body interactions

    NASA Astrophysics Data System (ADS)

    Alakhaly, Galal Ahmed; Dey, Bishwajyoti

    2015-05-01

    We have studied the dynamic evolution of the collective excitations in Bose-Einstein condensates in a deep optical lattice with tunable three-body interactions. Their dynamics is governed by a high order discrete nonlinear Schrödinger equation (DNLSE). The dynamical phase diagram of the system is obtained using the variational method. The dynamical evolution shows very interesting features. The discrete breather phase totally disappears in the regime where the three-body interaction completely dominates over the two-body interaction. The soliton phase in this particular regime exists only when the soliton line approaches the critical line in the phase diagram. When weak two-body interactions are reintroduced into this regime, the discrete breather solutions reappear, but occupies a very small domain in the phase space. Likewise, in this regime, the soliton as well as the discrete breather phases completely disappear if the signs of the two-and three-body interactions are opposite. We have analysed the causes of this unusual dynamical evolution of the collective excitations of the Bose-Einstein condensate with tunable interactions. We have also performed direct numerical simulations of the governing DNLS equation to show the existence of the discrete soliton solution as predicted by the variational calculations, and also to check the long term stability of the soliton solution.

  10. Melatonin receptors are present in non-optic regions of the brain of a deep-sea fish living in the absence of solar light.

    PubMed

    Smith, A; Trudeau, V L; Williams, L M; Martinoli, M G; Priede, I G

    1996-09-01

    Pineal melatonin hormonally transduces photoperiod to influence daily and seasonal cycles in most vertebrates (1, 2). Evidence of melatonin receptors throughout the brain of several fish species (3-5), particularly in retinorecipient structures, also indicates a role in visual processing. Despite the absence of solar light many deepsea organisms show seasonality (6-8). The presence of central melatonin receptors was investigated by quantitative in vitro autoradiography in the deep-sea fish Coryphaenoides (Nematonurus) armatus. Specific, time-dependent, saturable, high affinity and guanine nucleotide sensitive, 2-[125I]iodomelatonin binding was found over the mid-brain tegmentum and hindbrain. Competing ligand potency was iodomelatonin > melatonin > 5-HT. Although C.(N.) armatus has well developed eyes no 2-[125I]iodomelatonin binding occurred in optic tectum, cerebellum or hypothalamus. Thus melatonin involvement in processing of visual information and control of seasonal physiology via hypothalamic areas appears to be absent in this species. The presence of central G-protein coupled receptors indicates a function for melatonin unrelated to solar light.

  11. CCD Photometer Installed on the Telescope - 600 OF the Shamakhy Astrophysical Observatory II. The Technique of Observation and Data Processing of CCD Photometry

    NASA Astrophysics Data System (ADS)

    Abdullayev, B. I.; Gulmaliyev, N. I.; Majidova, S. O.; Mikayilov, Kh. M.; Rustamov, B. N.

    2009-12-01

    Basic technical characteristics of CCD matrix U-47 made by the Apogee Alta Instruments Inc. are provided. Short description and features of various noises introduced by optical system and CCD camera are presented. The technique of getting calibration frames: bias, dark, flat field and main stages of processing of results CCD photometry are described.

  12. BINARY STAR SYNTHETIC PHOTOMETRY AND DISTANCE DETERMINATION USING BINSYN

    SciTech Connect

    Linnell, Albert P.; DeStefano, Paul; Hubeny, Ivan E-mail: pdestefa@uw.edu

    2013-09-15

    This paper extends synthetic photometry to components of binary star systems. The paper demonstrates accurate recovery of single star photometric properties for four photometric standards, Vega, Sirius, GD153, and HD209458, ranging over the HR diagram, when their model synthetic spectra are placed in fictitious binary systems and subjected to synthetic photometry processing. Techniques for photometric distance determination have been validated for all four photometric standards.

  13. Essentials of photometry for clinical electrophysiology of vision.

    PubMed

    McCulloch, Daphne L; Hamilton, Ruth

    2010-08-01

    Electrophysiological testing of the visual system requires familiarity with photometry. This technical note outlines the concepts of photometry with a focus on information relevant to clinical ERG and VEP testing. Topics include photometric quantities, consideration of pupil size, specification of brief extended flash stimuli, and the influence of the spectral composition of visual stimuli. Standard units and terms are explained in the context of the ISCEV standards and guidelines for clinical electrophysiology of vision.

  14. Recent Advances in Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Meachem, Terry; Cooke, William J.

    2003-01-01

    One of the most common (and obvious) problems with video meteor data involves the saturation of the output signal produced by bright meteors, resulting in the elimination of such meteors from photometric determinations. It is important to realize that a "bright" meteor recorded by intensified meteor camera is not what would be considered "bright" by a visual observer - indeed, many Generation II or III camera systems are saturated by meteors with a visual magnitude of 3, barely even noticeable to the untrained eye. As the relatively small fields of view (approx.30 ) of the camera systems captures at best modest numbers of meteors, even during storm peaks, the loss of meteors brighter than +3 renders the determination of shower population indices from video observations even more difficult. Considerable effort has been devoted by the authors to the study of the meteor camera systems employed during the Marshall Space Flight Center s Leonid ground-based campaigns, and a calibration scheme has been devised which can extend the useful dynamic range of such systems by approximately 4 magnitudes. The calibration setup involves only simple equipment, available to amateur and professional, and it is hoped that use of this technique will make for better meteor photometry, and move video meteor analysis beyond the realm of simple counts.

  15. Microlensing for extrasolar planets : improving the photometry

    NASA Astrophysics Data System (ADS)

    Bajek, David J.

    2013-08-01

    Gravitational Microlensing, as a technique for detecting Extrasolar Planets, is recognised for its potential in discovering small-mass planets similar to Earth, at a distance of a few Astronomical Units from their host stars. However, analysing the data from microlensing events (which statistically rarely reveal planets) is complex and requires continued and intensive use of various networks of telescopes working together in order to observe the phenomenon. As such the techniques are constantly being developed and refined; this project outlines some steps of the careful analysis required to model an event and ensure the best quality data is used in the fitting. A quantitative investigation into increasing the quality of the original photometric data available from any microlensing event demonstrates that 'lucky imaging' can lead to a marked improvement in the signal to noise ratio of images over standard imaging techniques, which could result in more accurate models and thus the calculation of more accurate planetary parameters. In addition, a simulation illustrating the effects of atmospheric turbulence on exposures was created, and expanded upon to give an approximation of the lucky imaging technique. This further demonstrated the advantages of lucky images which are shown to potentially approach the quality of those expected from diffraction limited photometry. The simulation may be further developed for potential future use as a 'theoretical lucky imager' in our research group, capable of producing and analysing synthetic exposures through customisable conditions.

  16. BVRI PHOTOMETRY OF 53 UNUSUAL ASTEROIDS

    SciTech Connect

    Ye, Q.-Z.

    2011-02-15

    We present the results of BVRI photometry and classification of 53 unusual asteroids, including 35 near-Earth asteroids (NEAs), 6 high eccentricity/inclination asteroids, and 12 recently identified asteroid-pair candidates. Most of these asteroids were not classified prior to this work. For the few asteroids that have been previously studied, the results are generally in agreement. In addition to observing and classifying these objects, we merge the results from severalphotometric/spectroscopic surveys to create the largest-ever sample with 449 spectrally classified NEAs for statistical analysis. We identify a 'transition point' of the relative number of C/X-like and S-like NEAs at H {approx} 18 {r_reversible} D {approx} 1 km with confidence level at {approx}95% or higher. We find that the C/X-like:S-like ratio for 18 {<=} H < 22 is about twice as high as that of H < 18 (0.33 {+-} 0.04 versus 0.17 {+-} 0.02), virtually supporting the hypothesis that smaller NEAs generally have less weathered surfaces (therefore less reddish appearance) due to younger collision ages.

  17. BVI CCD photometry of 47 Tucanae

    SciTech Connect

    Alcaino, G.; Liller, W.

    1987-08-01

    CCD BVI main-sequence photometry of 47 Tuc is presented, matched to the recent BVI isochrones of VandenBerg and Bell (1985). The main-sequence turnoffs are found to be at V = 17.60 + or - 0.1, B-V = 0.56 + or - 0.02; V-I = 0.68 + or - 0.02, and B-I = 1.24 + or - 0.02. The magnitude difference between the main-sequence turnoff and the horizontal branch is 3.55 + or - 0.15 for all three color indices. A consistent age for 47 Tuc of 17 Gyr and a consistent distance modulus of (m-M)v = 13.2 are obtained for all three indices, and an absolute magnitude of Mv = 0.85 is determined for the horizontal branch stars. The results also favor the adoption of (Fe/H) near -0.5 as the best abundance value for 47 Tuc. 38 references.

  18. Probing Stellar Dynamics With Space Photometry

    NASA Astrophysics Data System (ADS)

    García, Rafael A.; Salabert, D.; Ballot, J.; Beck, P. G.; Bigot, L.; Corsaro, E.; Creevey, O.; Egeland, R.; Jiménez, A.; Mathur, S.; Metcalfe, T.; do Nascimento, J.; Pallé, P. L.; Pérez Hernández, F.; Regulo, C.

    2016-08-01

    The surface magnetic field has substantial influence on various stellar properties that can be probed through various techniques. With the advent of new space-borne facilities such as CoRoT and Kepler, uninterrupted long high-precision photometry is available for hundred of thousand of stars. This number will substantially grow through the forthcoming TESS and PLATO missions. The unique Kepler observations -covering up to 4 years with a 30-min cadence- allows studying stellar variability with different origins such as pulsations, convection, surface rotation, or magnetism at several time scales from hours to years. We study the photospheric magnetic activity of solar-like stars by means of the variability induced in the observed signal by starspots crossing the visible disk. We constructed a solar photometric magnetic activity proxy, Sph from SPM/VIRGO/SoHO, as if the Sun was a distant star and we compare it with several solar well-known magnetic proxies. The results validate this approach. Thus, we compute the Sph proxy for a set of CoRoT and Kepler solar-like stars for which pulsations were already detected. After characterizing the rotation and the magnetic properties of 300 solar-like stars, we use their seismic properties to characterize 18 solar analogs for which we study their magnetism. This allows us to put the Sun into context of its siblings.

  19. NEW UBVRI PHOTOMETRY OF 234 M33 STAR CLUSTERS

    SciTech Connect

    Ma Jun

    2013-04-15

    This is the second paper of our series. In this paper, we present UBVRI photometry for 234 star clusters in the field of M33. For most of these star clusters, there is photometry in only two bands in previous studies. The photometry of these star clusters is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements, and in particular that our photometry is in good agreement with that of Zloczewski and Kaluzny. Combined with star cluster photometry in previous studies, we present some results: none of the M33 youngest clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun }, and comparisons with models of simple stellar populations suggest a large range of ages for M33 star clusters and some as old as the Galactic globular clusters.

  20. FIXING THE U-BAND PHOTOMETRY OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Krisciunas, Kevin; Bastola, Deepak; Suntzeff, Nicholas B.; Espinoza, Juan; Gonzalez, David; Gonzalez, Luis; Gonzalez, Sergio; Hsiao, Eric Y.; Morrell, Nidia; Phillips, Mark M.; Hamuy, Mario E-mail: suntzeff@physics.tamu.edu E-mail: hsiao@lco.cl E-mail: mmp@lco.cl

    2013-01-01

    We present previously unpublished photometry of supernovae 2003gs and 2003hv. Using spectroscopically derived corrections to the U-band photometry, we reconcile U-band light curves made from imagery with the Cerro Tololo 0.9 m, 1.3 m, and Las Campanas 1 m telescopes. Previously, such light curves showed a 0.4 mag spread at one month after maximum light. This gives us hope that a set of corrected ultraviolet light curves of nearby objects can contribute to the full utilization of rest-frame U-band data of supernovae at redshift {approx}0.3-0.8. As pointed out recently by Kessler et al. in the context of the Sloan Digital Sky Survey supernova search, if we take the published U-band photometry of nearby Type Ia supernovae at face value, there is a 0.12 mag U-band anomaly in the distance moduli of higher redshift objects. This anomaly led the Sloan survey to eliminate from their analyses all photometry obtained in the rest-frame U-band. The Supernova Legacy Survey eliminated observer frame U-band photometry, which is to say nearby objects observed in the U-band, but they used photometry of high-redshift objects no matter in which band the photons were emitted.

  1. The Very Low Albedo of an Extrasolar Planet: MOST Space-based Photometry of HD 209458

    NASA Astrophysics Data System (ADS)

    Rowe, Jason F.; Matthews, Jaymie M.; Seager, Sara; Miller-Ricci, Eliza; Sasselov, Dimitar; Kuschnig, Rainer; Guenther, David B.; Moffat, Anthony F. J.; Rucinski, Slavek M.; Walker, Gordon A. H.; Weiss, Werner W.

    2008-12-01

    Measuring the albedo of an extrasolar planet provides insight into its atmospheric composition and its global thermal properties, including heat dissipation and weather patterns. Such a measurement requires very precise photometry of a transiting system, fully sampling many phases of the secondary eclipse. Space-based optical photometry of the transiting system HD 209458 from the MOST (Microvariablity and Oscillations of Stars) satellite, spanning 14 and 44 days in 2004 and 2005, respectively, allows us to set a sensitive limit on the optical eclipse of the hot exosolar giant planet in this system. Our best fit to the observations yields a flux ratio of the planet and star of 7 +/- 9 ppm (parts per million), which corresponds to a geometric albedo through the MOST bandpass (400-700 nm) of Ag = 0.038 +/- 0.045. This gives a 1 σ upper limit of 0.08 for the geometric albedo and a 3 σ upper limit of 0.17. HD 209458b is significantly less reflective than Jupiter (for which Ag would be about 0.5). This low geometric albedo rules out the presence of bright reflective clouds in this exoplanet's atmosphere. We determine refined parameters for the star and exoplanet in the HD 209458 system based on a model fit to the MOST light curve. MOST is a Canadian Space Agency mission, operated jointly by Dynacon, Inc., and the Universities of Toronto and British Columbia, with assistance from the University of Vienna.

  2. The IRAF/STSDAS Synthetic Photometry Package

    NASA Astrophysics Data System (ADS)

    Bushouse, H.; Simon, B.

    The Space Telescope Science Data Analysis System (STSDAS) Synthetic Photometry (Synphot) package is an IRAF-based suite of tasks designed to simulate photometric data and spectra as observed with the Hubble Space Telescope (HST). Tasks in the Synphot package can be used to make plots of HST instrument sensitivity curves and calibration target spectra, to predict count rates for observations in any available mode of the HST science instruments, and to examine photometric transformation relationships among the various HST observing modes as well as conventional photometric systems such as Johnson UBV and Stromgren uvby. The availability of on-line spectral atlases also provides for the capability of simulating HST observations of real astrophysical targets. Synphot is available to assist Guest Observers in preparing observing proposals and has proven useful in planning and optimizing HST observing programs due to its cross-instrument simulation capability. Passbands for all of the HST instrument components, as well as those of other conventional photometric systems, are stored in data tables and are referenced via a master component graph table. The component graph table essentially provides a map of all of the HST instruments and describes all allowed combinations of the various instrument components. The Synphot passband calculator utilizes user-supplied keywords to trace a path through the component graph table and multiply together the individual component throughputs to return the composite passband. A powerful spectrum calculator is used to create complicated composite spectra from various parameterized spectrum models, grids of model atmosphere spectra, and atlases of stellar spectrophotometry. Because the Synphot tasks are completely data driven, instrument observing modes can be changed and even entirely new instruments added without any modifications to the software. Therefore Synphot can be applied to any other telescopes and instruments simply by

  3. Mesopic luminance assessed with minimum motion photometry.

    PubMed

    Raphael, Sabine; MacLeod, Donald I A

    2011-08-25

    We measured the relative contribution of rods and cones to luminance across a range of photopic, mesopic, and scotopic adaptation levels and at various retinal eccentricities. We isolated the luminance channel by setting motion-based luminance nulls (minimum motion photometry) using annular stimuli. Luminance nulls between differently colored stimuli require equality in a weighted sum of rod and cone excitations. The relative cone weight increases smoothly from the scotopic range, where rods dominate, to photopic levels, where rod influence becomes negligible. The change from rod to cone vision does not occur uniformly over the visual field. The more peripheral the stimulus location, the higher is the light level required for cones to participate strongly. The relative cone contribution can be described by a sigmoid function of intensity, with two parameters that each depend on the eccentricity and spatial frequency of the stimulus. One parameter determines the "meso-mesopic" luminance--the center of the mesopic range, at which rod and cone contributions are balanced. This increases with eccentricity, reflecting an increase in the meso-mesopic luminance from 0.04 scotopic cd/m(2) at 2° eccentricity to 0.44 scotopic cd/m(2) at 18°. The second parameter represents the slope of the log-log threshold-versus-intensity curve (TVI curve) for rod vision. This parameter inversely scales the width of the mesopic range and increases only slightly with eccentricity (from 0.73 at 2° to 0.78 for vision at 18° off-axis).

  4. Dithering Strategies and Point-Source Photometry

    SciTech Connect

    Samsing, Johan; Kim, Alex G

    2011-02-22

    The accuracy in the photometry of a point source depends on the point-spread function (PSF), detector pixelization, and observing strategy. The PSF and pixel response describe the spatial blurring of the source, the pixel scale describes the spatial sampling of a single exposure, and the observing strategy determines the set of dithered exposures with pointing offsets from which the source flux is inferred. In a wide-field imaging survey, sources of interest are randomly distributed within the field of view and hence are centered randomly within a pixel. A given hardware configuration and observing strategy therefore have a distribution of photometric uncertainty for sources of fixed flux that fall in the field. In this article we explore the ensemble behavior of photometric and position accuracies for different PSFs, pixel scales, and dithering patterns. We find that the average uncertainty in the flux determination depends slightly on dither strategy, whereas the position determination can be strongly dependent on the dithering. For cases with pixels much larger than the PSF, the uncertainty distributions can be non-Gaussian, with rms values that are particularly sensitive to the dither strategy. We also find that for these configurations with large pixels, pointings dithered by a fractional pixel amount do not always give minimal average uncertainties; this is in contrast to image reconstruction for which fractional dithers are optimal. When fractional pixel dithering is favored, a pointing accuracy of better than {approx}0.15 {approx}0.15 pixel width is required to maintain half the advantage over random dithers.

  5. VizieR Online Data Catalog: VRIZJHK photometry around Alpha Cen (Kervella+, 2007)

    NASA Astrophysics Data System (ADS)

    Kervella, P.; Thevenin, F.

    2016-06-01

    table1.dat lists the background sources identified on deep CCD images of the close environment of Alpha Centauri (up to approximately 2.5'). Our VRIZ photometry has been complemented by JHK photometry extracted from the corresponding 2MASS images (Skrutskie et al., 2006AJ....131.1163S). This catalogue is particularly intended to provide a reference for future searches for faint companions of Alpha Centauri. Unavailable values are replaced by 99.00 in the table. We have revised the coordinates of the catalogue published in 2007. They are now much more consistent with reference astrometric catalogues such as 2MASS (Cat. II/246). There was a shift of typically 2 arcseconds between the 2MASS and SUSI2 coordinates, and now this is reduced to less than 0.5 arcsecond. We have also recomputed the photometric magnitudes using more accurate aperture corrections and instrument zero points The new version of the table is available on 13-Jun-2016, in place of the old one, in Vizier. (1 data file).

  6. Laser flare-cell photometry: methodology and clinical applications.

    PubMed

    Ladas, John G; Wheeler, Noel C; Morhun, Patrick J; Rimmer, Steven O; Holland, Gary N

    2005-01-01

    Diagnosis and management of intraocular inflammation involves the assessment of cells and protein levels ("flare") in the aqueous humor. These factors are difficult to quantify precisely on clinical examination alone. Laser flare-cell photometry provides an automated technique to quantify these factors objectively, and it has been used in a variety of research and clinical situations to assess anterior segment inflammation. Any new technique requires evaluation to determine accuracy and reproducibility of measured values, and initial applications require critical appraisal to assess the value of the technique. Both in vitro and in vivo studies of laser flare-cell photometry have been performed to determine its validity and utility as a research and clinical tool. This article reviews published studies that describe the technique of laser flare-cell photometry; it provides new in vitro data that supplements information on the capabilities of this technique and factors that influence photometry results, and it reviews representative publications that have used laser flare-cell photometry for study of specific disease entities. This information can help clinicians and researchers to become familiar with the strengths and limitations of laser flare-cell photometry, to identify appropriate future uses for this technique, and to use it and interpret its results appropriately. Laser flare-cell photometry offers an opportunity to improve upon current techniques of inflammation assessment and should not be considered simply an objective surrogate for clinical grading of cells and flare at the slit-lamp biomicroscope. Its research applications and utility for monitoring patients with uveitis have not yet been fully explored.

  7. Optical coherence tomography characteristics of different types of big bubbles seen in deep anterior lamellar keratoplasty by the big bubble technique.

    PubMed

    AlTaan, S L; Termote, K; Elalfy, M S; Hogan, E; Werkmeister, R; Schmetterer, L; Holland, S; Dua, H S

    2016-11-01

    PurposeTo define optical coherence tomography (OCT) characteristics of type-1, type-2, and mixed big bubbles (BB) seen in deep anterior lamellar keratoplasty.MethodsHuman sclero-corneal discs were obtained from UK (30) and Canada (16) eye banks. Air was injected into corneal stroma until a BB formed. UK samples were fixed in formalin before scanning with Fourier-domain (FD-OCT). One pair of each type of BB was scanned fresh. All BB obtained from Canada were scanned fresh with time-domain (TD-OCT). For each OCT machine used, type-1 BB from which Descemets membrane (DM) was partially peeled, were also scanned. The morphological characteristics of the scans were studied.ResultsFD-OCT of the posterior wall of type-1 (Dua's layer (DL) with DM) and type-2 BB (DM alone) both revealed a double-contour hyper-reflective curvilinear image with a hypo-reflective zone in between. The anterior line of type-2 BB was thinner than that seen with type-1 BB. In mixed BB, FD-OCT showed two separate curvilinear images. The anterior image was a single hyper-reflective line (DL), whereas the posterior image, representing the posterior wall of type-2 BB (DM) was made of two hyper-reflective lines with a dark space in between. TD-OCT images were similar with less defined component lines, but the entire extent of the BB could be visualised.ConclusionOn OCT examination the DM and DL present distinct features, which can help identify type-1, type-2, and mixed BB. These characteristics will help corneal surgeons interpret intraoperative OCT during lamellar corneal surgery.

  8. VizieR Online Data Catalog: YSOVAR: infrared photometry in NGC 1333 (Rebull+, 2015)

    NASA Astrophysics Data System (ADS)

    Rebull, L. M.; Stauffer, J. R.; Cody, A. M.; Gunther, H. M.; Hillenbrand, L. A.; Poppenhaeger, K.; Wolk, S. J.; Hora, J.; Hernandez, J.; Bayo, A.; Covey, K.; Forbrich, J.; Gutermuth, R.; Morales-Calderon, M.; Plavchan, P.; Song, I.; Bouy, H.; Terebey, S.; Cuillandre, J. C.; Allen, L. E.

    2016-06-01

    We present the Young Stellar Object VARiability (YSOVAR) data for NGC1333. There are 701 objects (see Table1) with mid-infrared light curves in one or both warm Spitzer bands. All YSOVAR Spitzer light curve tabular data are available via the YSOVAR data delivery to the Infrared Science Archive (IRSA; http://irsa.ipac.caltech.edu/frontpage/). The sky observed by the two IRAC channels (3.6 and 4.5μm, or IRAC-1 and -2) fields of view is slightly offset with the central ~10'*10' region, centered on 03:29:06+31:19:30, covered by both channels. The observations were obtained under program ID61026, between 2011 October 10 and November 14 (~35 days). Near-infrared observations were obtained using the Peters Automated Infrared Imaging Telescope (PAIRITEL), which is an automated 1.3m telescope. PAIRITEL was located at the Whipple Observatory at Mt. Hopkins, Arizona; the same telescope and camera used for the northern part of 2MASS, PAIRITEL acquired simultaneous J, H, and Ks images. The observations of NGC1333 were obtained over 24 epochs from 2010 October 7 to 2012 November 19. We compiled additional photometry from several different sources. Early in the Spitzer mission, NGC1333 was observed by both the guaranteed time observations (GTOs) and the Cores-to-Disks (c2d) Legacy program (Evans et al. 2009, cat. J/ApJS/181/321), with both IRAC and the Multiband Imaging Photometer for Spitzer (MIPS). NGC1333 was covered in the Two-Micron All Sky Survey (2MASS; see cat II/246) and was also located in a field targeted by the long exposure 6X 2MASS program (see cat II/281). As described in Rebull 2015 (cat. J/AJ/150/17), we included these main 2MASS catalog and deeper 6X catalog near-infrared JHKs data into our database. We also include the ~30 deep JH space-based measurements from Greissl et al. (2007AJ....133.1321G). Chandra X-ray Observatory Advanced CCD Imaging Spectrometer for wide-field imaging (ACIS-I) observations of NGC1333 were first reported in Getman et al. 2002 (cat. J

  9. DEEP MIPS OBSERVATIONS OF THE IC 348 NEBULA: CONSTRAINTS ON THE EVOLUTIONARY STATE OF ANEMIC CIRCUMSTELLAR DISKS AND THE PRIMORDIAL-TO-DEBRIS DISK TRANSITION

    SciTech Connect

    Currie, Thayne; Kenyon, Scott J. E-mail: skenyon@cfa.harvard.edu

    2009-09-15

    We describe new, deep MIPS photometry and new high signal-to-noise optical spectroscopy of the 2.5 Myr old IC 348 Nebula. To probe the properties of the IC 348 disk population, we combine these data with previous optical/infrared photometry and spectroscopy to identify stars with gas accretion, to examine their mid-IR colors, and to model their spectral energy distributions. IC 348 contains many sources in different evolutionary states, including protostars and stars surrounded by primordial disks, two kinds of transitional disks, and debris disks. Most disks surrounding early/intermediate spectral-type stars (>1.4 M {sub sun} at 2.5 Myr) are debris disks; most disks surrounding solar and subsolar-mass stars are primordial disks. At the 1-2 {sigma} level, more massive stars also have a smaller frequency of gas accretion and smaller mid-IR luminosities than lower-mass stars. These trends are suggestive of a stellar mass-dependent evolution of disks, where most disks around high/intermediate-mass stars shed their primordial disks on rapid, 2.5 Myr timescales. The frequency of MIPS-detected transitional disks is {approx}15%-35% for stars plausibly more massive than 0.5 M {sub sun}. The relative frequency of transitional disks in IC 348 compared to that for 1 Myr old Taurus and 5 Myr old NGC 2362 is consistent with a transition timescale that is a significant fraction of the total primordial disk lifetime.

  10. Deep MIPS Observations of the IC 348 Nebula: Constraints on the Evolutionary State of Anemic Circumstellar Disks and the Primordial-to-Debris Disk Transition

    NASA Astrophysics Data System (ADS)

    Currie, Thayne; Kenyon, Scott J.

    2009-09-01

    We describe new, deep MIPS photometry and new high signal-to-noise optical spectroscopy of the 2.5 Myr old IC 348 Nebula. To probe the properties of the IC 348 disk population, we combine these data with previous optical/infrared photometry and spectroscopy to identify stars with gas accretion, to examine their mid-IR colors, and to model their spectral energy distributions. IC 348 contains many sources in different evolutionary states, including protostars and stars surrounded by primordial disks, two kinds of transitional disks, and debris disks. Most disks surrounding early/intermediate spectral-type stars (>1.4 M sun at 2.5 Myr) are debris disks; most disks surrounding solar and subsolar-mass stars are primordial disks. At the 1-2 σ level, more massive stars also have a smaller frequency of gas accretion and smaller mid-IR luminosities than lower-mass stars. These trends are suggestive of a stellar mass-dependent evolution of disks, where most disks around high/intermediate-mass stars shed their primordial disks on rapid, 2.5 Myr timescales. The frequency of MIPS-detected transitional disks is ≈15%-35% for stars plausibly more massive than 0.5 M sun. The relative frequency of transitional disks in IC 348 compared to that for 1 Myr old Taurus and 5 Myr old NGC 2362 is consistent with a transition timescale that is a significant fraction of the total primordial disk lifetime.

  11. CCD Photometry of the Classic Second-Parameter Globular Clusters M3 and M13

    NASA Astrophysics Data System (ADS)

    Rey, Soo-Chang; Yoon, Suk-Jin; Lee, Young-Wook; Chaboyer, Brian; Sarajedini, Ata

    2001-12-01

    We present high-precision V, B-V color-magnitude diagrams (CMDs) for the classic second-parameter globular clusters M3 and M13 from wide-field, deep CCD photometry. The data for the two clusters were obtained during the same photometric nights with the same instrument, allowing us to determine accurate relative ages. Based on a differential comparison of the CMDs using the Δ(B-V) method, an age difference of 1.7+/-0.7 Gyr is obtained between these two clusters. We compare this result with our updated horizontal-branch (HB) population models, which confirm that the observed age difference can produce the difference in HB morphology between the clusters. This provides further evidence that age is the dominant second parameter that influences HB morphology. Data were obtained using the 2.4 m Hiltner Telescope of the Michigan-Dartmouth-MIT (MDM) Observatory.

  12. Faint quasi-stellar-object candidates in selected areas 28 and 68 identified from multicolor photometry

    SciTech Connect

    Shields, J.C.; Koo, D.C.; Kron, R.C.; California Univ., Berkeley; Lick Observatory, Santa Cruz, CA; Yerkes Observatory, Williams Bay, WI )

    1989-04-01

    Forty-five QSO candidates over a total area of 0.53 square degree in two fields at high Galactic latitudes have been identified. These candidates reached B of about 21.5 for field Lynx.3 in SA 28 and B of about 22 for field SA68.2, and were selected from a subset of objects in catalogs generated from multicolor photometry (UBV) of deep Kitt Peak 4-m plates with limits of B of about 24. This subset consists of all objects which appeared stellar-like in size but which did not have the UBV colors of common Galactic stars. Besides several probable high-redshift QSOs, this study yields faint QSO counts consistent with those from other surveys, and thus provides further support to models that include mainly the luminosity evolution of QSOs. 29 refs.

  13. Disk-resolved photometry of Asteroid (2867) Steins

    NASA Astrophysics Data System (ADS)

    Spjuth, S.; Jorda, L.; Lamy, P. L.; Keller, H. U.; Li, J.-Y.

    2012-11-01

    We present a new method to perform disk-resolved photometry in order to investigate the intrinsic photometric properties of the surface of small Solar System bodies. We adopt the standard approach where a shape model is combined with a photometric formalism - in practise the Hapke formalism - to remove the effects of topography and recover the photometric (Hapke) parameters of either the global surface or, in its most elaborated form, the spatial variations of these parameters across the surface. Our method operates in the space of the facets representing the three-dimensional shape of the body, whereas all past analysis have always been performed in the space of the image pixels although they are not intrinsic to the surface of the body. This has the advantage of automatically tracking the same local surface element on a series of images. We first apply our method to images of the nucleus of Comet 9P/Tempel 1 obtained by the High-Resolution Imager (HRI) instrument on board the Deep Impact spacecraft and our derived Hapke parameters are in good agreement with those published by Li et al. (Li, J.-Y. et al. [2007]. Icarus 187, 41-55) within their respective uncertainties. We confirm the presence of an extended region of higher roughness in the southern hemisphere of the nucleus and the higher albedo of the ice-rich regions identified by Sunshine et al. (Sunshine, J.M. et al. [2006]. Science 311, 1453-1455) near the equator. The photometric properties of Asteroid (2867) Steins are then studied from multi-spectral images obtained with the OSIRIS Wide Angle Camera (WAC) on board the Rosetta spacecraft during its flyby on 5 September 2008. Our analysis indicates that the surface is highly porous (∼84%) and that it exhibits both a shadow-hiding opposition effect (SHOE) and probably, a coherent-backscatter opposition effect (CBOE). The single scattering albedo is the highest (SSA = 0.57) ever observed among small bodies visited by spacecrafts. Our modelled roughness

  14. CCD surface photometry of galaxies with dynamical data. II. UBR photometry of 39 elliptical galaxies

    SciTech Connect

    Peletier, R.F.; Davies, R.L.; Davis, L.E.; Illingworth, G.D.; Cawson, M. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA National Optical Astronomical Observatory, Tucson, AZ Lick Observatory, Santa Cruz, CA Steward Observatory, Tucson, AZ Manchester Victoria Univ. )

    1990-10-01

    Intrinsic properties of elliptical galaxies and the mechanisms of their formation and evolution are discussed on the basis of high-precision, multicolor, surface photometry of 39 elliptical galaxies and measurements of rotation curves and velocity dispersion profiles. Using the data collected, a number of correlations between the characteristic parameters of the stellar population of the galaxies have been made to explore their structure and kinematics. The luminosity dependence of color gradients is a good discriminant among various models of galaxy formation. The lowest luminosity galaxies in the sample do not show any color gradients. They have boxy isophotes, and are also rotationally flattened. These properties may be related to the fact that they are companions of larger ellipsoidal systems and it could also provide an important clue to the formation of ellipticals. 78 refs.

  15. Uranian Satellites and Triton: JHK Photometry

    NASA Astrophysics Data System (ADS)

    Kesten, P. R.; Davies, J. K.; Cruikshank, D. P.; Roush, T. L.

    1998-09-01

    We report photometric measurements of Uranian satellites Miranda, Ariel, Umbriel, and Titania (10.4 Aug. 1995), and Neptune's satellite Triton (21.2 Sept. 1995) with the infrared camera (IRCAM) and standard J (1.13-1.42 mu m), H (1.53-1.81 mu m), and K (2.00-2.41 mu m) filters at the 3.8-m UKIRT telescope on Mauna Kea. The individual image frames are 256 x 256 pixels with an image scale of 0.286 arcsec/pixel, resulting in a 1.22 arcmin field of view. The standard star used for airmass correction and flux calibration was UKIRT FS 34 (EG141). The photometric information for the Uranian satellites was derived from 5-image mosaics created after dark frame and flat-field corrections; a circular aperture approximation based on DAOPHOT/aper-irtf (P. B. Stetson, PASP 99, 191, 1987) was used except in the case of Miranda, in which a linear fit to the strong background light gradient from the nearby image of Uranus was applied. The center of Uranus was 9.7 arcsec (measured on the images) from Miranda. Triton data were extracted from individual images (not mosaics) with an 8-arcsec aperture and a sky anulus 10-15 arcsec. The phase angle of the Uranian satellites was alpha =1.0(o) , and that of Triton was alpha =1.7(o) . The resulting magnitudes are as follows: Miranda J = 15.30 +/-.05, H = 15.14 +/-.05, K = 15.40 +/-.06; Ariel J = 12.96 +/-.04, H = 12.86 +/-.04, K = 13.04 +/-.04; Umbriel J = 13.60 +/-.04, H = 13.37 +/-.04, K = 13.44 +/-.04; Titania J = 12.58 +/-.04, H = 12.44 +/-.04, K = 12.60 +/-.04; Triton J = 12.26 +/-.04, H = 12.14 +/-.04, K = 12.31 +/-.04. Other reports of Uranian satellite photometry are: P. D. Nicholson and T. J. Jones (Icarus 42, 54, 1980), D. P. Cruikshank (Icarus 41, 246, 1980), and K. H. Baines et al. (Icarus 132, 266, 1998).

  16. COOL WHITE DWARFS FOUND IN THE UKIRT INFRARED DEEP SKY SURVEY

    SciTech Connect

    Leggett, S. K.; Nitta, A.; Lodieu, N.

    2011-07-01

    We present the results of a search for cool white dwarfs in the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The UKIDSS LAS photometry was paired with the Sloan Digital Sky Survey to identify cool hydrogen-rich white dwarf candidates by their neutral optical colors and blue near-infrared colors, as well as faint reduced proper motion magnitudes. Optical spectroscopy was obtained at Gemini Observatory and showed the majority of the candidates to be newly identified cool degenerates, with a small number of G- to K-type (sub)dwarf contaminants. Our initial search of 280 deg{sup 2} of sky resulted in seven new white dwarfs with effective temperature T{sub eff} {approx} 6000 K. The current follow-up of 1400 deg{sup 2} of sky has produced 13 new white dwarfs. Model fits to the photometry show that seven of the newly identified white dwarfs have 4120 K {<=}T{sub eff} {<=} 4480 K, and cooling ages between 7.3 Gyr and 8.7 Gyr; they have 40 km s{sup -1} {<=} v{sub tan} {<=} 85 km s{sup -1} and are likely to be thick disk 10-11 Gyr-old objects. The other half of the sample has 4610 K {<=}T{sub eff} {<=} 5260 K, cooling ages between 4.3 Gyr and 6.9 Gyr, and 60 km s{sup -1} {<=} v{sub tan} {<=} 100 km s{sup -1}. These are either thin disk remnants with unusually high velocities, or lower-mass remnants of thick disk or halo late-F or G stars.

  17. CCD Photometry of bright stars using objective wire mesh

    SciTech Connect

    Kamiński, Krzysztof; Zgórz, Marika; Schwarzenberg-Czerny, Aleksander

    2014-06-01

    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  18. HUBBLE SPACE TELESCOPE Photometry of the Globular Cluster M4

    NASA Astrophysics Data System (ADS)

    Ibata, Rodrigo A.; Richer, Harvey B.; Fahlman, Gregory G.; Bolte, Michael; Bond, Howard E.; Hesser, James E.; Pryor, Carlton; Stetson, Peter B.

    1999-02-01

    This paper presents a detailed description of the acquisition and processing of a large body of imaging data for three fields in the globular cluster M4 taken with the Wide Field and Planetary Camera 2 aboard the Hubble Space Telescope. Analysis with the ALLFRAME package yielded the deepest photometry yet obtained for this cluster. The resulting data set for 4708 stars (positions and calibrated photometry in V, I, and, in two fields, U) spanning approximately six cluster core radii is presented. The scientific analysis is deferred to three companion papers, which investigate the significant white dwarf population discovered and the main-sequence population.

  19. Deep Galex Observations of the Coma Cluster: Source Catalog and Galaxy Counts

    NASA Technical Reports Server (NTRS)

    Hammer, D.; Hornschemeier, A. E.; Mobasher, B.; Miller, N.; Smith, R.; Arnouts, S.; Milliard, B.; Jenkins, L.

    2010-01-01

    We present a source catalog from deep 26 ks GALEX observations of the Coma cluster in the far-UV (FUV; 1530 Angstroms) and near-UV (NUV; 2310 Angstroms) wavebands. The observed field is centered 0.9 deg. (1.6 Mpc) south-west of the Coma core, and has full optical photometric coverage by SDSS and spectroscopic coverage to r-21. The catalog consists of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically-confirmed Coma member galaxies that range from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is 80% complete to NUV=23 and FUV=23.5, and has a limiting depth at NUV=24.5 and FUV=25.0 which corresponds to a star formation rate of 10(exp -3) solar mass yr(sup -1) at the distance of Coma. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies. This required a two-fold approach to generating a source catalog: we used a Bayesian deblending algorithm to measure faint and compact sources (using SDSS coordinates as a position prior), and used the GALEX pipeline catalog for bright and/or extended objects. We performed simulations to assess the importance of systematic effects (e.g. object blends, source confusion, Eddington Bias) that influence source detection and photometry when using both methods. The Bayesian deblending method roughly doubles the number of source detections and provides reliable photometry to a few magnitudes deeper than the GALEX pipeline catalog. This method is also free from source confusion over the UV magnitude range studied here: conversely, we estimate that the GALEX pipeline catalogs are confusion limited at NUV approximately 23 and FUV approximately 24. We have measured the total UV galaxy counts using our catalog and report a 50% excess of counts across FUV=22-23.5 and NUV=21.5-23 relative to previous GALEX

  20. VizieR Online Data Catalog: Radial velocity and photometry for GJ3470 (Bonfils+, 2012)

    NASA Astrophysics Data System (ADS)

    Bonfils, X.; Gillon, M.; Udry, S.; Armstrong, D.; Bouchy, F.; Delfosse, X.; Forveille, T.; Fumel, A.; Jehin, E.; Lendl, M.; Lovis, C.; Mayor, M.; McCormac, J.; Neves, V.; Pepe, F.; Perrier, C.; Pollaco, D.; Queloz, D.; Santos, N. C.

    2012-11-01

    The tables contain radial-velocity and photometry time series of GJ3470. Radial velocities were obtained with he HARPS spectrograph. Photometry was obtained with TRAPPIST, EulerCam and NITES telescopes. (5 data files).

  1. Galileo Photometry of Asteroid 951 Gaspra

    USGS Publications Warehouse

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T.V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, R.L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

    1994-01-01

    Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over phase angles 2?? ??? ?? ??? 25?? with Galileo whole-disk and disk-resolved data at 33?? ??? ?? ??? 51?? to derive average global photometric properties in terms of Hapke's photometric model. The microscopic texture and particle phase-function behavior of Gaspra's surface are remarkably like those of other airless rocky bodies such as the Moon. The macroscopic surface roughness parameter, ??̄ = 29??, is slightly larger than that reported for typical lunar materials. The particle single scattering albedo, ??́0 = 0.36 ?? 0.07, is significantly larger than for lunar materials, and the opposition surge amplitude, B0 = 1.63 ?? 0.07, is correspondingly smaller. We determine a visual geometric albedo pv = 0.22 ?? 0.06 for Gaspra, in close agreement with pv = 0.22 ?? 0.03 estimated from Earth-based observations. Gaspra's phase integral is 0.47, and the bolometric Bond albedo is estimated to be 0.12 ?? 0.03. An albedo map derived by correcting Galileo images with our average global photometric function reveals subdued albedo contrasts of ??10% or less over Gaspra's northern hemisphere. Several independent classification algorithms confirm the subtle spectral heterogeneity reported earlier (S. Mottola, M. DiMartino, M. Gonano-Beurer, H. Hoffman, and G. Neukum, 1993, Asteroids, Comets, Meteors, pp. 421-424; M. J. S. Belton et al., 1992, Science 257, 1647-1652). Whole-disk colors (0.41 ??? ?? ??? 0.99 ??m) vary systematically with longitude by about ??5%, but color differences as large as 30% occur locally. Colors vary continuously between end-member materials whose areal distribution correlates with regional topography. Infrared

  2. The MOSFIRE Deep Evolution Field (MOSDEF) Survey: Rest-frame Optical Spectroscopy for ~1500 H-selected Galaxies at 1.37 < z < 3.8

    NASA Astrophysics Data System (ADS)

    Kriek, Mariska; Shapley, Alice E.; Reddy, Naveen A.; Siana, Brian; Coil, Alison L.; Mobasher, Bahram; Freeman, William R.; de Groot, Laura; Price, Sedona H.; Sanders, Ryan; Shivaei, Irene; Brammer, Gabriel B.; Momcheva, Ivelina G.; Skelton, Rosalind E.; van Dokkum, Pieter G.; Whitaker, Katherine E.; Aird, James; Azadi, Mojegan; Kassis, Marc; Bullock, James S.; Conroy, Charlie; Davé, Romeel; Kereš, Dušan; Krumholz, Mark

    2015-06-01

    In this paper we present the MOSFIRE Deep Evolution Field (MOSDEF) survey. The MOSDEF survey aims to obtain moderate-resolution (R = 3000-3650) rest-frame optical spectra (˜3700-7000 Å) for ˜1500 galaxies at 1.37≤ z≤ 3.80 in three well-studied CANDELS fields: AEGIS, COSMOS, and GOODS-N. Targets are selected in three redshift intervals: 1.37≤ z≤ 1.70, 2.09≤ z≤ 2.61, and 2.95≤ z≤ 3.80, down to fixed {H}{AB} (F160W) magnitudes of 24.0, 24.5, and 25.0, respectively, using the photometric and spectroscopic catalogs from the 3D-HST survey. We target both strong nebular emission lines (e.g., [O ii] λ λ 3727,3730, Hβ, [O iii] λ λ 4960,5008, Hα, [N ii] λ λ 6550,6585, and [S ii] λ λ 6718,6733) and stellar continuum and absorption features (e.g., Balmer lines, Ca-ii H and K, Mgb, 4000 Å break). Here we present an overview of our survey, the observational strategy, the data reduction and analysis, and the sample characteristics based on spectra obtained during the first 24 nights. To date, we have completed 21 masks, obtaining spectra for 591 galaxies. For ˜80% of the targets we derive a robust redshift from either emission or absorption lines. In addition, we confirm 55 additional galaxies, which were serendipitously detected. The MOSDEF galaxy sample includes unobscured star-forming, dusty star-forming, and quiescent galaxies and spans a wide range in stellar mass (˜ {10}9-{10}11.5 {M}⊙ ) and star formation rate (˜ {10}0-{10}3 {M}⊙ {{yr}}-1). The spectroscopically confirmed sample is roughly representative of an H-band limited galaxy sample at these redshifts. With its large sample size, broad diversity in galaxy properties, and wealth of available ancillary data, MOSDEF will transform our understanding of the stellar, gaseous, metal, dust, and black hole content of galaxies during the time when the universe was most active.

  3. Homogeneous Photometry. IV. On the Standard Sequence in the Globular Cluster NGC 2419

    NASA Astrophysics Data System (ADS)

    Stetson, Peter B.

    2005-06-01

    I present a new analysis of CCD-based BVRI broadband photometry for the globular cluster NGC 2419, based on 340 CCD images either donated by colleagues or retrieved from public archives. The calibrated results have been made available through my Web site. I compare the results of my analysis with those of an independent analysis of a subset of these data by Saha et al. (2005, PASP, 117, 37), who have found a color-dependent discrepancy of up to 0.05 mag between their I-band photometry and mine for stars in this cluster. I conclude that a major part of the discrepancy appears to be associated with small shutter timing errors (a few hundredths of a second) in the Mini-Mosaic (MIMO) camera on the WIYN 3.5 m telescope. Smaller contributions to the anomaly likely come from (1) a color-scale error with a maximum amplitude of ~+/-0.02 mag in my secondary standard list as of 2004 September, and (2) statistical effects arising from the previous study's use of a relatively small number of standard-star observations to determine a comparatively large number of fitting parameters in the photometric transformations. Based in part on observations obtained at the 3.5 m and 0.9 m WIYN Telescopes. The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatory (NOAO).

  4. VizieR Online Data Catalog: 1889-2015 photometry of Stingray nebula (Schaefer+, 2015)

    NASA Astrophysics Data System (ADS)

    Schaefer, B. E.; Edwards, Z. I.

    2016-02-01

    To get broad-band magnitudes for the Stingray, we have pulled from a wide variety of sources --the Harvard photographic plate collection from 1889 to 1989, the visual magnitude estimates of Albert Jones as archived by the American Association of Variable Star Observers (AAVSO) from 1994 to 2007, the All Sky Automated Survey (ASAS) from 2001 to 2009, the AAVSO telescopes going into the AAVSO Photometric All-sky Survey (APASS) from 2011 to 2015, plus our own photometry from CCD images with DECam on the Cerro Tololo 4-m Blanco telescope from 2014. We have added 15 mag from the literature or derived by us from the literature, all on six nights from 1969 to 1996. At our request, A. Henden has put the Stingray in the queue for time series photometry on the 0.61-m Optical Craftsmen Telescope at the Mount John Observatory in New Zealand. The 1-minute CCD integrations were through a Johnson V filter on the nights of 2015 March 23, 26, and 27. (1 data file).

  5. WIDE-FIELD MULTIBAND PHOTOMETRY OF GLOBULAR CLUSTER SYSTEMS IN THE FORNAX GALAXY CLUSTER

    SciTech Connect

    Kim, Hak-Sub; Yoon, Suk-Jin; Chung, Chul; Lee, Sang-Yoon; Lee, Young-Wook; Sohn, Sangmo Tony; Kim, Sang Chul; Kim, Eunhyeuk

    2013-01-20

    We present wide-field multiband photometry of globular cluster (GC) systems in NGC 1399, NGC 1404, and NGC 1387 located in the central region of the Fornax galaxy cluster. Observation was carried out through U, B, V, and I bands, which marks one of the widest and deepest U-band studies on extragalactic GC systems. The present U-band photometry enables us to significantly reduce the contamination by a factor of two for faint sources (V {sub 0} {approx} 23.5). The main results based on some 2000 GC candidates around NGC 1399, NGC 1404, and NGC 1387 are as follows: (1) the GC system in each galaxy exhibits bimodal color distributions in all colors examined, but the shape of color histograms varies systematically depending on colors; (2) NGC 1399 shows that the mean colors of both blue and red GCs become bluer with increasing galactocentric radius; (3) NGC 1399 shows overabundance of GCs in the directions of NGC 1404 and NGC 1387, indicating their ongoing interactions; and (4) NGC 1399 also exhibits a {approx}0.'5 offset between the center of the inner GC distribution and the galaxy's optical center, suggesting that NGC 1399 is not yet dynamically relaxed and may be undergoing merger events.

  6. INTEGRATED STELLAR POPULATIONS: CONFRONTING PHOTOMETRY WITH SPECTROSCOPY

    SciTech Connect

    MacArthur, Lauren A.; McDonald, Michael; Courteau, Stephane; Gonzalez, J. Jesus

    2010-08-01

    We investigate the ability of spectroscopic techniques to yield realistic star formation histories (SFHs) for the bulges of spiral galaxies based on a comparison with their observed broadband colors. Full spectrum fitting to optical spectra indicates that recent (within {approx}1 Gyr) star formation activity can contribute significantly to the V-band flux, whilst accounting for only a minor fraction of the stellar mass budget which is made up primarily of old stars. Furthermore, recent implementations of stellar population (SP) models reveal that the inclusion of a more complete treatment of the thermally pulsating asymptotic giant branch (TP-AGB) phase to SP models greatly increases the NIR flux for SPs of ages 0.2-2 Gyr. Comparing the optical-NIR colors predicted from population synthesis fitting, using models which do not include all stages of the TP-AGB phase, to the observed colors reveals that observed optical-NIR colors are too red compared to the model predictions. However, when a 1 Gyr SP from models including a full treatment of the TP-AGB phase is used, the observed and predicted colors are in good agreement. This has strong implications for the interpretation of stellar populations, dust content, and SFHs derived from colors alone.

  7. Infrared space observatory photometry of circumstellar dust in Vega-type systems

    NASA Technical Reports Server (NTRS)

    Fajardo-Acosta, S. B.; Stencel, R. E.; Backman, D. E.; Thakur, N.

    1998-01-01

    The ISOPHOT (Infrared Space Observatory Photometry) instrument onboard the Infrared Space Observatory (ISO) was used to obtain 3.6-90 micron photometry of Vega-type systems. Photometric data were calibrated with the ISOPHOT fine calibration source 1 (FCS1). Linear regression was used to derive transformations to make comparisons to ground-based and IRAS photometry systems possible. These transformations were applied to the photometry of 14 main-sequence stars. Details of these results are reported on.

  8. REVIEW ARTICLE: Photometry, radiometry and 'the candela': evolution in the classical and quantum world

    NASA Astrophysics Data System (ADS)

    Zwinkels, Joanne C.; Ikonen, Erkki; Fox, Nigel P.; Ulm, Gerhard; Rastello, Maria Luisa

    2010-10-01

    The metrological fields of photometry and radiometry and their associated units are closely linked through the current definition of the base unit of luminous intensity—the candela. These fields are important to a wide range of applications requiring precise and accurate measurements of electromagnetic radiation and, in particular, the amount of radiant energy (light) that is perceived by the human eye. The candela has been one of the base units since the inception of the International System of Units (SI) and is the only base unit that quantifies a fundamental biological process—human vision. This photobiological process spans an enormous dynamic range of light levels from a few-photon interaction involved in triggering the vision mechanism to a level of more than 1015 photons per second that is accommodated by the visual response under bright daylight conditions. This position paper, prepared by members of the Task Group on the SI of the Consultative Committee for Photometry and Radiometry Strategic Planning Working Group (CCPR WG-SP), reviews the evolution of these fields of optical radiation measurements and their consequent impact on definitions and realization of the candela. Over the past several decades, there have been significant developments in sources, detectors, measuring instruments and techniques, that have improved the measurement of photometric and radiometric quantities for classical applications in lighting design, manufacturing and quality control processes involving optical sources, detectors and materials. These improved realizations largely underpin the present (1979) definition of the candela. There is no consensus on whether this radiant-based definition fully satisfies the current and projected needs of the optical radiation community. There is also no consensus on whether a reformulation of the definition of the candela in terms of photon flux will be applicable to the lighting community. However, there have been significant recent

  9. NEAR-INFRARED THERMAL EMISSION DETECTIONS OF A NUMBER OF HOT JUPITERS AND THE SYSTEMATICS OF GROUND-BASED NEAR-INFRARED PHOTOMETRY

    SciTech Connect

    Croll, Bryce; Albert, Loic; Lafreniere, David; Jayawardhana, Ray; Cushing, Michael; Moutou, Claire; Johnson, John Asher; Bonomo, Aldo S.; Deleuil, Magali; Fortney, Jonathan

    2015-03-20

    We present detections of the near-infrared thermal emission of three hot Jupiters and one brown dwarf using the Wide-field Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT). These include Ks-band secondary eclipse detections of the hot Jupiters WASP-3b and Qatar-1b and the brown dwarf KELT-1b. We also report Y-band, K {sub CONT}-band, and two new and one reanalyzed Ks-band detections of the thermal emission of the hot Jupiter WASP-12b. We present a new reduction pipeline for CFHT/WIRCam data, which is optimized for high precision photometry. We also describe novel techniques for constraining systematic errors in ground-based near-infrared photometry, so as to return reliable secondary eclipse depths and uncertainties. We discuss the noise properties of our ground-based photometry for wavelengths spanning the near-infrared (the YJHK bands), for faint and bright stars, and for the same object on several occasions. For the hot Jupiters WASP-3b and WASP-12b we demonstrate the repeatability of our eclipse depth measurements in the Ks band; we therefore place stringent limits on the systematics of ground-based, near-infrared photometry, and also rule out violent weather changes in the deep, high pressure atmospheres of these two hot Jupiters at the epochs of our observations.

  10. Deep VLT/HAWKI and Keck/MOSFIRE K-band imaging of the Hubble Frontier Fields

    NASA Astrophysics Data System (ADS)

    Brammer, Gabriel; Marchesini, Danilo

    2015-08-01

    We will present recently-obtained deep K-band imaging of the first four Frontier Fields, Abell 2744 and MACS 0416 with the VLT/HAWK-I instrument and MACS-0717 and MACS-1149 with Keck/MOSFIRE. The final HAWK-I mosaics reach a depth of K~26 AB (5-sigma) with superb ground-based image quality ~0.4" FWHM across the field; shorter integrations with MOSFIRE reach K~25 AB and with FWHM~0.5". The 7'x7' HAWKI field of view provides ideal simultaneous coverage of both the HST cluster and parallel fields (with additional area also covered by Subaru optical and IRAC imaging), and the K band at 2.2 µm crucially fills the gap between the deep space-based imaging bandpasses observed with HST and Spitzer. The addition of the 2.2 µm imaging and photometry greatly improves the constraints on both the photometric redshifts and the stellar-population properties of galaxies extending well below the characteristic stellar mass across most of the age of the universe, down to, and including, the redshifts of the targeted galaxy clusters. The reduced, aligned mosaics of all the K-band fields are made freely available to the Frontier Fields community; identical deep HAWK-I observations of the final two Frontier Fields (Abell 370 and Abell S1063) have been awarded and will be obtained in the upcoming ESO observing periods.

  11. Results of CCD Transit Photometry Testing for the Kepler Mission

    NASA Astrophysics Data System (ADS)

    Koch, D.; Witteborn, F.; Dunham, E.; Jenkins, J.; Borucki, W.; Webster, L.

    1999-12-01

    Transit signals produced by Earth-size planets in orbit around solar-like stars are of the order of 8e-5 and have durations from 4 to 16 hours for planets in or near the habitable zone. A mission to search for habitable planets has been proposed (Koch, et al., 1998). At the heart of the mission is an array of CCDs used to continuously measure the relative brightness variations of 100,000 dwarf stars for transits. A testbed facility has been constructed to determine the effects of various induced noise sources on the capability of a CCD photometer to maintain an instrument relative precision of better than 1e-5. The photometry facility includes: a simulated star field with an approximate solar spectrum, fast optics to simulate the space borne telescope, a thinned back-illuminated CCD similar to those to be used on the spacecraft operating at 1 Mpix/sec read rate, and shutterless operation. The test facility is thermally and mechanically isolated. Each source of noise is introduced in a controlled fashion and evaluated. Pointing noise or changing thermal conditions in the spacecraft can cause star-image motion at the milli-pixel level. These motions are imposed by piezo-electric devices that move the photometer relative to the star field. Transit signals as small as Earth-size transits of solar-like stars are generated and measured. This is accomplished by electrical self-heating and expansion of fine wires placed across many of the star apertures. The small decrease in stellar brightness is used to demonstrate that Earth-size planets can be detected under realistic noise conditions and at the shot-noise-limited level. The effects of imposing several noise sources are shown and the resulting detectability of planets is presented. This work is supported in part by the NASA Discovery program and NASA Ames. Koch, D., Borucki, W., Webster, L., Dunham, E., Jenkins, J., Marriott, J. and Reitsema, H. SPIE Conf. on Space Telescopes and Instruments V, 3356, 599-607 (1998)

  12. JCMT COADD: UKT14 continuum and photometry data reduction

    NASA Astrophysics Data System (ADS)

    Hughes, David; Oliveira, Firmin J.; Tilanus, Remo P. J.; Jenness, Tim

    2014-11-01

    COADD was used to reduce photometry and continuum data from the UKT14 instrument on the James Clerk Maxwell Telescope in the 1990s. The software can co-add multiple observations and perform sigma clipping and Kolmogorov-Smirnov statistical analysis. Additional information on the software is available in the JCMT Spring 1993 newsletter (large PDF).

  13. Iontophoresis and Flame Photometry: A Hybrid Interdisciplinary Experiment

    ERIC Educational Resources Information Center

    Sharp, Duncan; Cottam, Linzi; Bradley, Sarah; Brannigan, Jeanie; Davis, James

    2010-01-01

    The combination of reverse iontophoresis and flame photometry provides an engaging analytical experiment that gives first-year undergraduate students a flavor of modern drug delivery and analyte extraction techniques while reinforcing core analytical concepts. The experiment provides a highly visual demonstration of the iontophoresis technique and…

  14. TNO Photometry and Spectroscopy at ESO and Calar Alto

    NASA Astrophysics Data System (ADS)

    Boehnhardt, H.; Sekiguchi, T.; Vair, M.; Hainaut, O.; Delahodde, C.; West, R. M.; Tozzi, G. P.; Barrera, L.; Birkle, K.; Watanabe, J.; Meech, K.

    New photometry and spectroscopy of Transneptunian objects (TNO) has been obtained at ESO (VLT+FORS1, NTT+SOFI) and the Calar Alto (3.5m+MOSCA) observatory. BVRI photometry of more than 10 objects confirms the general colour-colour distribution of TNOs found previously. Quasi-simultaneous spectroscopy in the visible wavelength range of 5 TNOs did not reveal any spectral signature apart from the spetral gradients which are in agreement with the broadband colours. JHK filter photometry of 3 objects indicates that the reddening may only occur in the near-IR at least in some cases. Using new observations from the ESO VLT the lightcurve, colours and spectrum of 1996TO66 are investigated: the rotation period of 6.25h is confirmed, also the change in the lightcurve between 1997 and 1998 which indicates an exceptional behaviour in this object (temporary cometary activity ?). The 1999 photometry and spectroscopy in the visible revealed solar colours, no reddening and no spectral features. V-R colour changes over the rotation phase are not found. This works is done in colaboration with:

  15. VizieR Online Data Catalog: GMASS photometry (Kurk+, 2013)

    NASA Astrophysics Data System (ADS)

    Kurk, J.; Cimatti, A.; Daddi, E.; Mignoli, M.; Pozzetti, L.; Dickinson, M.; Bolzonella, M.; Zamorani, G.; Cassata, P.; Rodighiero, G.; Franceschini, A.; Renzini, A.; Rosati, P.; Halliday, C.; Berta, S.

    2012-10-01

    Properties of objects observed in the GMASS masks, including the GMASS identification number, coordinates, photometry in four bands, redshifts determined from spectroscopy, average S/N per pixel in spectrum, photometric normalisation factor to obtain imaging flux, sample of which the target is part and mask(s) in which the target was observed. (2 data files).

  16. Multiband photometry of PSNJ14102342-4318437 with OAUNI

    NASA Astrophysics Data System (ADS)

    Pereyra, A.; Cori, W.; Ricra, J.; Zevallos, M.; Tello, J.

    2016-01-01

    We report multiband photometry of Type Ib SN PSNJ14102342-4318437 (ATel #8415, ATel #8434, ATel #8437, ATel #8504) on 2016-01-10 (UT) gathered with the OAUNI 51cm telescope (Pereyra et al. 2015; arXiv:1512.03104) at Huancayo Observatory, Peru.

  17. Photoelectric photometry of J V. [Jupiter satellite Amalthea

    NASA Technical Reports Server (NTRS)

    Millis, R. L.

    1978-01-01

    UBV photometry of J V (Amalthea) near greatest western elongation shows this satellite to be about one magnitude fainter than previously believed. It is observed to be very red, having a B-V color index near + 1.5 mag. Unlike the Galilean satellites, J V appears to be a low-albedo object.

  18. Characterization of Transiting Exoplanets by Way of Differential Photometry

    ERIC Educational Resources Information Center

    Cowley, Michael; Hughes, Stephen

    2014-01-01

    This paper describes a simple activity for plotting and characterizing the light curve from an exoplanet transit event by way of differential photometry analysis. Using free digital imaging software, participants analyse a series of telescope images with the goal of calculating various exoplanet parameters, including size, orbital radius and…

  19. Follow-up photometry of iPTF16geu

    NASA Astrophysics Data System (ADS)

    Lee, C.-H.

    2016-10-01

    We report follow-up photometry of the strongly lensed SNIa iPTF16geu (ATel #9603, #9626). We observed iPTF16geu on 2016/10/17 with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma, under ~0.9" seeing condition.

  20. BVRI Photometry of the Supernova Candidate Gaia16ath

    NASA Astrophysics Data System (ADS)

    Vinko, J.; Feher, T.; Gyurita, A.; Redli, M.; Sukolova, D.

    2016-07-01

    We report confirmation and photometry of the recently discovered Gaia Science Alerts transient Gaia16ath. CCD frames were taken with the 60/90 cm Schmidt telescope through Bessell B,V,R,I filters at Konkoly Observatory, Piszkesteto, Hungary on July 11.01 UT. The transient was detected with high significance (S/N > 20) in all bands.

  1. Validation and Characterization of K2 Exoplanet Candidates with NIR Transit Photometry from the 4m Mayall and 3.5m WIYN Telescopes

    NASA Astrophysics Data System (ADS)

    Colón, Knicole D.; Barclay, Thomas

    2016-06-01

    We present new ground-based near-infrared (NIR) transit photometry of exoplanet candidates recently discovered by the NASA K2 mission. These observations support the confirmation and characterization of these newly discovered transiting exoplanets, many which are in the super-Earth to mini-Neptune size regime and orbit cool, nearby stars. We specifically used NEWFIRM on the 4m Mayall telescope and WHIRC on the 3.5m WIYN telescope, both located at Kitt Peak National Observatory, to observe several K2 exoplanet candidates in transit. To our knowledge, these facilities have not been tested for such high-precision differential transit photometry before. Follow-up transit photometry with the high spatial resolution NIR cameras installed on the Mayall and WIYN telescopes allows us to confirm the transit host, which is critical given the large pixel scale of the Kepler spacecraft. NIR transit photometry in particular allows us to verify that the transit is achromatic, after comparing the NIR transit depth to the transit depth measured in the optical from K2. Finding a different depth in different bandpasses indicates that the candidate is instead an eclipsing binary false positive. Furthermore, NIR transit photometry provides robust constraints on the measured planet radius, since stellar limb darkening is minimized in the NIR. Finally, the high-precision and high-cadence photometry we achieve allows us to refine the transit ephemeris, which is crucial for future follow-up efforts with other facilities like NASA's James Webb Space Telescope. The capabilities of these ground-based facilities therefore approach those of space telescopes, since we are able use these ground-based observatories to refine transit parameters and constrain properties for the exoplanets that K2 is discovering, all the way down to super-Earth-size planets.

  2. HIGH-CADENCE, HIGH-CONTRAST IMAGING FOR EXOPLANET MAPPING: OBSERVATIONS OF THE HR 8799 PLANETS WITH VLT/SPHERE SATELLITE-SPOT-CORRECTED RELATIVE PHOTOMETRY

    SciTech Connect

    Apai, Dániel; Skemer, Andrew; Hanson, Jake R.; Kasper, Markus; Lagrange, Anne-Marie; Bonnefoy, Mickaël; Biller, Beth A.; Buenzli, Esther; Vigan, Arthur

    2016-03-20

    Time-resolved photometry is an important new probe of the physics of condensate clouds in extrasolar planets and brown dwarfs. Extreme adaptive optics systems can directly image planets, but precise brightness measurements are challenging. We present VLT/SPHERE high-contrast, time-resolved broad H-band near-infrared photometry for four exoplanets in the HR 8799 system, sampling changes from night to night over five nights with relatively short integrations. The photospheres of these four planets are often modeled by patchy clouds and may show large-amplitude rotational brightness modulations. Our observations provide high-quality images of the system. We present a detailed performance analysis of different data analysis approaches to accurately measure the relative brightnesses of the four exoplanets. We explore the information in satellite spots and demonstrate their use as a proxy for image quality. While the brightness variations of the satellite spots are strongly correlated, we also identify a second-order anti-correlation pattern between the different spots. Our study finds that KLIP reduction based on principal components analysis with satellite-spot-modulated artificial-planet-injection-based photometry leads to a significant (∼3×) gain in photometric accuracy over standard aperture-based photometry and reaches 0.1 mag per point accuracy for our data set, the signal-to-noise ratio of which is limited by small field rotation. Relative planet-to-planet photometry can be compared between nights, enabling observations spanning multiple nights to probe variability. Recent high-quality relative H-band photometry of the b–c planet pair agrees to about 1%.

  3. Deep Earthquakes.

    ERIC Educational Resources Information Center

    Frohlich, Cliff

    1989-01-01

    Summarizes research to find the nature of deep earthquakes occurring hundreds of kilometers down in the earth's mantle. Describes further research problems in this area. Presents several illustrations and four references. (YP)

  4. Fast IR photometry of V404 Cyg in outburst with CIRCE/GTC

    NASA Astrophysics Data System (ADS)

    Dallilar, Yigit; Eikenberry, Stephen S.; Garner, Alan; Stelter, Richard D.; Gandhi, Poshak; Hardy, Liam K.; Dhillon, Vik S.; Littlefair, Stuart; Fender, Rob; Mooley, Kunal P.

    2016-01-01

    We used the fast photometry mode of the 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 25th for about one and a half hour 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 two optical bands (g'-r') from ULTRACAM on the William Herschel 4.2-meter telescope. We extract spectral indices from the three radio bands and an optical-to-infrared color index from infrared and optical lightcurves. With a positive and increasing radio spectral index, we have identified an infrared outburst about 30 minutes with a clear self absorbed synchrotron ejection event. We further investigate the correlation between spectral indexes and multi wavelength flux measurements to understand evolution of ejection event. We also report on very fast IR flares and their correlation with optical events.

  5. An infrared and optical analysis of a sample of XBONGs and optically elusive AGNs

    SciTech Connect

    Smith, K. L.; Mushotzky, R. F.; Koss, M. E-mail: richard@astro.umd.edu

    2014-10-20

    We present near-infrared (NIR) spectra of four optically elusive active galactic nuclei (AGNs) and four X-ray bright, optically normal galaxies (XBONGs) from the Swift-BAT survey. With archival observations from the Sloan Digital Sky Survey, the Two Micron All Sky Survey, Spitzer, and the Wide-field Infrared Survey Explorer (WISE), we test a number of AGN indicators in the NIR and mid-infrared; namely, NIR emission line diagnostic ratios, the presence of coronal high-ionization lines, and infrared photometry. Of our eight hard X-ray selected AGNs, we find that optical normalcy has a variety of causes from object to object, and no one explanation applies. Our objects have normal Eddington ratios and so are unlikely to host radiatively inefficient accretion flows. It is unlikely that star formation in the host or starlight dilution is contributing to their failure of optical diagnostics, except perhaps in two cases. The NIR continua are well fit by two blackbodies: one at the stellar temperature, and a hot dust component near the dust sublimation temperature. The XBONGs are more likely to have significant hot dust components, while these components are small relative to starlight in the optically elusive AGN. Some of our sample have NIR line ratios typical of AGNs, but NIR diagnostics are unsuccessful in distinguishing H II regions from AGNs in general. In one object, we discover a hidden broad-line region in the NIR. These results have strong relevance to the origin of optically normal AGNs in deep X-ray surveys.

  6. Crowded Field Photometry in the CLASH Clusters: Measuring the Red Sequence of Cluster Galaxies with Robust Photometry

    NASA Astrophysics Data System (ADS)

    Connor, Thomas; Donahue, Megan; Moustakas, John; Kelson, Daniel; Coe, Dan A.; Postman, Marc; CLASH Team

    2016-01-01

    The Cluster Lensing And Supernova survey with Hubble (CLASH) is an HST multi-cycle treasury program investigating 25 massive clusters of galaxies with X-ray gas Tx > 5 keV, spanning ~5 to ~30 x 10^14 solar masses, and a redshift range of 0.15 < z < 0.9. With 500 orbits of HST time and 16-filter, ultraviolet to infrared photometry of each cluster, this survey offers an unprecedented dataset for cluster galaxy photometry across a span of age and mass, but obtaining robust photometry for the cluster members has been hampered by the crowded field. We have developed a new technique to detect and define objects despite the presence of overlapping light profiles and to measure photometry of galaxies overlapping the extended haloes of massive galaxies. Utilizing spectral energy distribution fitting, we infer the properties of the detected galaxies, including their abundances and the time since their first star formation. Here we will discuss our technique and results, including the role metallicity and age play in shaping the red sequence of cluster galaxies.

  7. COLOR AND STELLAR POPULATION GRADIENTS IN PASSIVELY EVOLVING GALAXIES AT z {approx} 2 FROM HST/WFC3 DEEP IMAGING IN THE HUBBLE ULTRA DEEP FIELD

    SciTech Connect

    Guo Yicheng; Giavalisco, Mauro; Cassata, Paolo; Salimbeni, Sara; Ferguson, Henry C.; Koekemoer, Anton; Grogin, Norman A.; Lotz, Jennifer M.; Dickinson, Mark; Renzini, Alvio; Papovich, Casey; Tundo, Elena; Fontana, Adriano

    2011-07-01

    We report the detection of color gradients in six massive (stellar mass (M{sub star}) > 10{sup 10} M{sub sun}) and passively evolving (specific star formation rate <10{sup -11} yr{sup -1}) galaxies at redshift 1.3 < z < 2.5 identified in the Hubble Ultra Deep Field using ultra-deep Hubble Space Telescope (HST) Advanced Camera for Surveys and WFC3/IR images. After carefully matching the different point-spread functions, we obtain color maps and multi-band optical/near-IR photometry (BVizYJH) in concentric annuli, from the smallest resolved radial distance ({approx}1.7 kpc) up to several times the H-band effective radius. We find that the inner regions of these galaxies have redder rest-frame UV-optical colors (U - V, U - B, and B - V) than the outer parts. The slopes of the color gradient have no obvious dependence on the redshift and on the stellar mass of the galaxies. They do mildly depend, however, on the overall dust obscuration (E(B - V)) and rest-frame (U - V) color, with more obscured or redder galaxies having steeper color gradients. The z {approx} 2 color gradients are also steeper than those of local early-type ones. The gradient of a single parameter (age, extinction, or metallicity) cannot fully explain the observed color gradients. Fitting the spatially resolved HST seven-band photometry to stellar population synthesis models, we find that, regardless of assumptions on the metallicity gradient, the redder inner regions of the galaxies have slightly higher dust obscuration than the bluer outer regions, implying that dust partly contributes to the observed color gradients, although the magnitude depends on the assumed extinction law. Due to the age-metallicity degeneracy, the derived age gradient depends on the assumptions for the metallicity gradient. We discuss the implications of a number of assumptions for metallicity gradients on the formation and evolution of these galaxies. We find that the evolution of the mass-size relationship from z {approx} 2

  8. Color and Stellar Population Gradients in Passively Evolving Galaxies at z ~ 2 from HST/WFC3 Deep Imaging in the Hubble Ultra Deep Field

    NASA Astrophysics Data System (ADS)

    Guo, Yicheng; Giavalisco, Mauro; Cassata, Paolo; Ferguson, Henry C.; Dickinson, Mark; Renzini, Alvio; Koekemoer, Anton; Grogin, Norman A.; Papovich, Casey; Tundo, Elena; Fontana, Adriano; Lotz, Jennifer M.; Salimbeni, Sara

    2011-07-01

    We report the detection of color gradients in six massive (stellar mass (M star) > 1010 M ⊙) and passively evolving (specific star formation rate <10-11 yr-1) galaxies at redshift 1.3 < z < 2.5 identified in the Hubble Ultra Deep Field using ultra-deep Hubble Space Telescope (HST) Advanced Camera for Surveys and WFC3/IR images. After carefully matching the different point-spread functions, we obtain color maps and multi-band optical/near-IR photometry (BVizYJH) in concentric annuli, from the smallest resolved radial distance (≈1.7 kpc) up to several times the H-band effective radius. We find that the inner regions of these galaxies have redder rest-frame UV-optical colors (U - V, U - B, and B - V) than the outer parts. The slopes of the color gradient have no obvious dependence on the redshift and on the stellar mass of the galaxies. They do mildly depend, however, on the overall dust obscuration (E(B - V)) and rest-frame (U - V) color, with more obscured or redder galaxies having steeper color gradients. The z ~ 2 color gradients are also steeper than those of local early-type ones. The gradient of a single parameter (age, extinction, or metallicity) cannot fully explain the observed color gradients. Fitting the spatially resolved HST seven-band photometry to stellar population synthesis models, we find that, regardless of assumptions on the metallicity gradient, the redder inner regions of the galaxies have slightly higher dust obscuration than the bluer outer regions, implying that dust partly contributes to the observed color gradients, although the magnitude depends on the assumed extinction law. Due to the age-metallicity degeneracy, the derived age gradient depends on the assumptions for the metallicity gradient. We discuss the implications of a number of assumptions for metallicity gradients on the formation and evolution of these galaxies. We find that the evolution of the mass-size relationship from z ~ 2 to the present cannot be driven by in situ

  9. IR photometry and models for the dust envelopes of two carbon stars

    NASA Astrophysics Data System (ADS)

    Bogdanov, M. B.; Taranova, O. G.

    2016-12-01

    The results of JHKLM photometry of two carbon stars are presented: the irregular variable NQ Cas and the Mira star BD Vul. Data on the mean fluxes supplemented with mid-IR observations with the IRAS, AKARI, andWISE satellites are used to compute spherically symmetrical model dust envelopes for the stars, consisting of particles of amorphous carbon and silicon carbide. The optical depth in the visible for the comparatively cool dust envelope of BD Vul, with a dust temperature at its inner boundary T 1 = 610 K, is fairly low: τ V = 0.13. The dust envelope of NQ Cas is appreciably hotter ( T 1 = 1550 K), and has τ V = 0.32. The estimated mass-loss rates are 1.5 × 10-7 M ⊙/yr for NQ Cas and 5.9 × 10-7 M ⊙/yr for BD Vul.

  10. Near-infrared surface photometry and morphology in virgo cluster spiral galaxy nuclear regions

    NASA Astrophysics Data System (ADS)

    Rauscher, Bernard J.

    1995-04-01

    This paper presents very high spatial resolution (seeing 0.75 arcsec FWHM) K band surface photometry of 15 Virgo cluster spiral galaxy nuclear regions (radii less then 1 kpc). It presents B and I CCD images of 13 of these galaxies. The goals of the study were: (1) to begin to establish a K band baseline of normal spiral galaxy nuclear regions against which peculiar galaxies may be compared, (2) to provide better contsraints on N-body models, and (3) to complement near-infrared studies of large scale structure in spiral galaxies with very high resolution imaging of the important nuclear regions. The principle findings are (1) between 1/4 and 1/3 of these nuclear regions show K band evidence of traxiality, (2) approximately 1/2 of these galaxies have axisymmetric nuclear regions, and (3) NGC 4321 has a bar that is not detectable in the optical images.

  11. Macular pigment density and distribution: comparison of fundus autofluorescence with minimum motion photometry.

    PubMed

    Robson, Anthony G; Moreland, Jack D; Pauleikhoff, Daniel; Morrissey, Tony; Holder, Graham E; Fitzke, Fred W; Bird, Alan C; van Kuijk, Frederik J G M

    2003-07-01

    Macular pigment (MP) distribution profiles were measured for 18 subjects using a Moreland anomaloscope modified for motion photometry. The total amount of MP within the central 7 degrees was estimated from the distribution profile by numerical integration. Fundus autofluorescence images were obtained for eight of these subjects using a scanning laser ophthalmoscope. Peak optical density of MP increased with the total amount present, but the correlation was weakened by inter-subject differences in MP distribution. The mean MP distribution derived from mean grey-scale profiles of fundus autofluorescence images correlated closely with that obtained psychophysically (r=0.96). Autofluorescence imaging provides a fast non-invasive method for assessing MP in vivo.

  12. High resolution Halpha spectroscopy and R-band photometry of Swift J1357.2-0933

    NASA Astrophysics Data System (ADS)

    Casares, Jorge; Torres, Manuel A. P.; Negueruela, Ignacio; Gonzalez-Fernandez, Carlos; Corral-Santana, Jesus M.; Zurita, Cristina; Llano, Sergio Rodriguez

    2011-03-01

    We report on high resolution Halpha spectroscopy and time-resolved photometry of the optical counterpart to the X-ray transient Swift J1357.2-0933 in outburst (Krimm et al. ATEL #3138). SPECTROSCOPY: Six 30-33 min spectra were obtained on the nights of 2011 Feb 25-27 using the IDS Spectrograph on the 2.5m Isaac Newton Telescope (INT) at the Observatorio del Roque de Los Muchachos. The observations were performed with the H1800V grating and a slit width 1.6 arcsec to yield a spectral coverage of 6270-7000 Angs with a 30 km/s FWHM spectral resolution at Halpha..

  13. Fitting Photometry of Blended Microlensing Events

    NASA Astrophysics Data System (ADS)

    Thomas, Christian L.; Griest, Kim

    2006-03-01

    We reexamine the usefulness of fitting blended light-curve models to microlensing photometric data. We find agreement with previous workers (e.g., Woźniak & Paczyński) that this is a difficult proposition because of the degeneracy of blend fraction with other fit parameters. We show that follow-up observations at specific point along the light curve (peak region and wings) of high-magnification events are the most helpful in removing degeneracies. We also show that very small errors in the baseline magnitude can result in problems in measuring the blend fraction and study the importance of non-Gaussian errors in the fit results. The biases and skewness in the distribution of the recovered blend fraction is discussed. We also find a new approximation formula relating the blend fraction and the unblended fit parameters to the underlying event duration needed to estimate microlensing optical depth.

  14. VizieR Online Data Catalog: VRI photometry in NGC 7129 (Dahm+, 2015)

    NASA Astrophysics Data System (ADS)

    Dahm, S. E.; Hillenbrand, L. A.

    2015-06-01

    Three epochs of optical imaging data were obtained of the NGC 7129 region between 1993 and 1999. The first and most extensive survey consisted of VRCIC-band CCD imaging obtained using the T2KA CCD at the Kitt Peak National Observatory (KPNO) 0.9m telescope in 1993 June by LAH and S. Strom. The T2KA detector is a 2048*2048 CCD with 24μm pixels yielding a platescale of 0.69pixel-1. The complete list of all ~2500 sources from the T2KA CCD imaging survey of NGC 7129 including J2000 coordinates, optical (V, V-RC, and RC-IC) photometry, and associated photometric errors is provided in Table 4. The second epoch of RCIC-band photometry was obtained using the Low Resolution Imaging Spectrograph (LRIS) on Keck II in 1999 June by LAH. Finally BVRCIC photometry of the NGC 7129 region was obtained in 1999 October at the f/10 focus of the University of Hawaii (UH) 2.2m telescope on Mauna Kea by G. H. Herbig. The detector was a Tektronix 2048*2048 CCD with 24μm pixels. The field was imaged in all filters during photometric conditions and in average seeing conditions for Mauna Kea, 0.75". The plate scale was 0.22pixel-1, and the imaged field was approximately 7.5'*7.5' in area. The Hα emission survey of NGC 7129 was carried out on 10 October 2003 by SED using the Wide-Field Grism Spectrograph (WFGS) installed at the f/10 Cassegrain focus of the University of Hawaii 2.2m telescope. A 420 line mm-1 grism blazed at 6400Å yielded a dispersion of 3.85Å/pixel. The narrowband Hα filter isolated a region of the first-order spectra between ~6300 and 6750Å. The WFGS imaged upon the central 1024*1024 pixels of a Tektronix 2048*2048 pixel CCD, yielding a nominal field of view ~5.5'*5.5'. The WFGS survey covered a region of about 150 arcmin2, roughly centered upon LkHα 234. Low-dispersion spectra were obtained using HYDRA on WIYN in 1993 and the RC Spectrograph on the Mayall 4m telescope in 1994 by LAH. (4 data files).

  15. VizieR Online Data Catalog: HST photometry of stars in HD 97950 (Pang+, 2016)

    NASA Astrophysics Data System (ADS)

    Pang, X.; Pasquali, A.; Grebel, E. K.

    2016-07-01

    The HD97950 cluster and its immediate surroundings in the giant HII region NGC3603 were observed with the Hubble Space Telescope (HST). The ultraviolet (UV) data were taken with the High Resolution Channel (HRC) of the Advanced Camera for Surveys (ACS) in 2005 (GO 10602, PI: Jesus Maiz Apellaniz) through the F220W, F250W, F330W, and F435W filters. The HRC is characterized by a spatial resolution of 0.03"/pixel and a field of view of 29''*25''. The optical observations were carried out with the Wide Field and Planetary Camera 2 (WFPC2) in two epochs: 1997 (GO 6763, PI: Laurent Drissen) and 2007 (GO 11193, PI: Wolfgang Brandner) through the F555W, F675W, and F814W filters. The Planetary Camera (PC) chip was centered on the cluster (0.045"/pixel, 40''*40'') for both programs. Pang et al. 2013 (cat. J/ApJ/764/73) reduced the two-epoch WFPC2 data and identified more than 400 member stars on the PC chip via relative proper motions. Of these member stars, 142 are in common between the HRC and PC images and thus have UV and optical photometry available (see Table1). Among the HD97950 cluster member stars determined from relative proper motions (Pang et al. 2013, cat. J/ApJ/764/73, Table2), there are five main-sequence (MS) stars located in the cluster with projected distances of r<0.7pc from the center, for which there are also spectral types available from Table3 of Melena et al. (2008AJ....135..878M). The photometry of these five MS stars is presented in Table2. The individual color excesses and extinctions of the member main sequence stars are listed in Table3. (3 data files).

  16. Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

    NASA Astrophysics Data System (ADS)

    Beccari, G.; De Marchi, G.; Panagia, N.; Valenti, E.; Carraro, G.; Romaniello, M.; Zoccali, M.; Weidner, C.

    2015-01-01

    Context. We present a study of the mass accretion rates of pre-main sequence (PMS) stars in the cluster Trumpler 14 (Tr 14) in the Carina Nebula. Using optical multiband photometry we were able to identify 356 PMS stars showing Hα excess emission with equivalent width EW(Hα) > 20 Å. We interpret this observational feature as an indication that these objects are still actively accreting gas from their circumstellar medium. From a comparison of the HR diagram with PMS evolutionary models we derive ages and masses of the PMS stars. We find that most of the PMS objects are younger than 10 Myr with a median age of ~3 Myr. Surprisingly, we also find that ~20% of the mass accreting objects are older than 10 Myr. For each PMS star in Trumpler 14 we determine the mass accretion rate (Ṁacc) and discuss its dependence on mass and age. We finally combine the optical photometry with near-IR observations to build the spectral energy distribution (SED) for each PMS star in Tr 14. The analysis of the SEDs suggests the presence of transitional discs in which a large amount of gas is still present and sustains accretion onto the PMS object at ages older than 10 Myr. Our results, discussed in light of recent recent discoveries with Herschel of transitional discs containing a massive gas component around the relatively old PMS stars TW Hydrae, 49 Ceti, and HD 95086, support a new scenario n which old and evolved debris discs still host a significant amount of gas. Aims: Methods: Results:

  17. High speed photometry of AN UMa

    SciTech Connect

    Imamura, J.N.; Steiman-Cameron, T.Y.; Durisen, R.H.

    1985-01-01

    As a class, the AM Her objects exhibit temporal variability on time scales ranging from seconds to years. Most of the variations can be adequately described by ''shot noise'' models (Cordova and Mason 1982). Exceptions to this are the strictly periodic features modulated on the orbital periods of the systems (typically several hours) and the one to two second features which show up as ''excesses'' of power in the time averaged power spectra of AN UMa (Middleditch 1982) and E1405-451 (Mason et al. 1983; Larsson 1985). It has been suggested that the short time scale features are due to an oscillatory ''instability'' of radiative accretion shocks discovered by Langer, Chanmugam, and Shaviv (1981, 1982). This is an interesting suggestion because, if true, it would allow the masses of the accreting white dwarfs to be inferred and would provide other significant constraints on the physics of the accretion flows (see Langer et al. 1981, 1982; Chevalier and Imamura 1982; Imamura, Wolff, and Durisen 1984; Imamura 1985). Unfortunately, a direct physical relationship between the one to two second optical variations and shock oscillations has not yet been demonstrated. Because of the potential importance of such a result further study of these systems is clearly warranted. In this work, we examine the short time scale behavior of AN UMa in more detail and improve on the work of Middleditch (1982) by resolving the feature in time.

  18. Photometry of the comet 2060 Chiron

    NASA Technical Reports Server (NTRS)

    Buratti, Bonnie J.; Marcialis, Robert L.; Dunbar, R. Scott

    1991-01-01

    The comet 2060 Chiron has proven to be an interesting and enigmatic object. Situated between the orbits of Saturn and Uranus, it was originally classified as the most distant asteroid. It began to show cometary behavior in 1987 by increasing a full magnitude in brightness and developing a coma; there is evidence also for similar earlier outbursts. A thorough study of Chiron is important for two reasons: (1) it is a transition object defining the relationship between comets, asteroids, and meteorites; and (2) a full description of its changes in brightness - particularly on time scale of hours - will provide an empirical foundation for understanding the physical mechanisms (including outgassing, sublimation of volatiles, and even significant mass ejections) driving the evolution of comets. Short term outbursts were observed in early 1989, and a rapid decrease in brightness of Chiron's coma was observed in 1990 in the V and R filters. Also, a rotational lightcurve was detected of the nucleus with an amplitude only 1/4 that observed in its quiescent state: this fact indicates the increased importance of the optically thin coma to the observed brightness.

  19. VERY LATE PHOTOMETRY OF SN 2011fe

    SciTech Connect

    Kerzendorf, W. E.; Taubenberger, S.; Seitenzahl, I. R.; Ruiter, A. J.

    2014-12-01

    The Type Ia supernova SN 2011fe is one of the closest supernovae of the past decades. Due to its proximity and low dust extinction, this object provides a very rare opportunity to study the extremely late time evolution (>900 days) of thermonuclear supernovae. In this Letter, we present our photometric data of SN 2011fe taken at an unprecedented late epoch of ≈930 days with GMOS-N mounted on the Gemini North telescope (g = 23.43 ± 0.28, r = 24.14 ± 0.14, i = 23.91 ± 0.18, and z = 23.90 ± 0.17) to study the energy production and retention in the ejecta of SN 2011fe. Together with previous measurements by other groups, our result suggests that the optical supernova light curve can still be explained by the full thermalization of the decay positrons of {sup 56}Co. This is in spite of theoretical predicted effects (e.g., infrared catastrophe, positron escape, and dust) that advocate a substantial energy redistribution and/or loss via various processes that result in a more rapid dimming at these very late epochs.

  20. Deep learning.

    PubMed

    LeCun, Yann; Bengio, Yoshua; Hinton, Geoffrey

    2015-05-28

    Deep learning allows computational models that are composed of multiple processing layers to learn representations of data with multiple levels of abstraction. These methods have dramatically improved the state-of-the-art in speech recognition, visual object recognition, object detection and many other domains such as drug discovery and genomics. Deep learning discovers intricate structure in large data sets by using the backpropagation algorithm to indicate how a machine should change its internal parameters that are used to compute the representation in each layer from the representation in the previous layer. Deep convolutional nets have brought about breakthroughs in processing images, video, speech and audio, whereas recurrent nets have shone light on sequential data such as text and speech.