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Sample records for deep optical photometry

  1. Deep Surface Photometry of M87 with 13 Optical Bands

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Zhou, Xu; Ma, Jun; Wu, Hong; Yang, Yanbin; Li, Jiuli; Chen, Jiansheng

    2005-06-01

    Multicolor surface photometry of M87 was undertaken with the Beijing-Arizona-Taiwan-Connecticut photometric system, which contains 13 optical bands covering a range from 3800 to 10000 Å. Radial profiles have been derived for surface brightness, ellipticity, position angle, and the residuals from the fitted ellipses. The results show a good agreement with pure elliptical isophotes for M87, and no obvious substructure or dust is detected out to r=500'', corresponding to 40 kpc from the center. The surface brightness profile at r<190'' is well fitted by the de Vaucouleurs law. Moreover, a cD envelope is detected outside that radius. Given the surface brightness profiles of the 13 bands, the spectral energy distribution (SED) of M87 is obtained as a function of semimajor axis (SMA). By fitting the observed SEDs to synthetic ones derived from the PEGASE model, we explored the star formation history (SFH) of this giant elliptical galaxy. In the hypothesis that the evolution time T of M87 is the same as the mean age of its globular clusters, about 14 Gyr, we find that the characteristic timescale τ of the SFH increases monotonically from 2 to 7 Gyr as a function of SMA, while the luminosity-weighted mean stellar ages range from about 11 to 9 Gyr in a mild decrease, and the mean stellar metallicity Z drops from 0.017 to 0.014 as the SMA increases to r=500''. In the range 40''

  2. DEEP OPTICAL PHOTOMETRY OF SIX FIELDS IN THE ANDROMEDA GALAXY

    SciTech Connect

    Brown, Thomas M.; Smith, Ed; Ferguson, Henry C.; Kalirai, Jason S.; Guhathakurta, Puragra; Renzini, Alvio; Rich, R. Michael; VandenBerg, Don A. E-mail: edsmith@stsci.edu E-mail: jkalirai@stsci.edu E-mail: randy.a.kimble@nasa.gov E-mail: alvio.renzini@oapd.inaf.it E-mail: vandenbe@uvic.ca

    2009-09-01

    Using the Advanced Camera for Surveys on the Hubble Space Telescope, we have obtained deep optical images reaching well below the oldest main-sequence turnoff in six fields of the Andromeda Galaxy. The fields fall at four positions on the southeast minor axis, one position in the giant stellar stream, and one position on the northeast major axis. These data were obtained as part of three large observing programs designed to probe the star formation history of the stellar population in various structures of the galaxy. In this paper, we present the images, catalogs, and artificial star tests for these observing programs as a supplement to the analyses published previously. These high-level science products are also archived at the Multimission Archive at the Space Telescope Science Institute.

  3. Deep near-infrared and optical imaging photometry of the Serpens cloud core

    NASA Astrophysics Data System (ADS)

    Giovannetti, Philippe; Caux, Emmanuel

    few x 10^4 yrs) earliest protostellar stage. In this poster we present new deep optical and near-infrared observations of the Serpens cloud core using array detectors. We estimate our completeness limits to be 24, 23, 23, 19, 18.5 and 17.0 at V, R, I, J, H and K respectively, although sources as faint as K=17.6 were detected. We surveyed an area of 4'x4.8' centered approximately on the Serpens Reflexion Nebula at alpha(1950)=18h27m24s and delta(1950) = 1d 12'41". 165 sources are detected in the area surveyed which represents an increase of 60 objects. The fact that we have obtained near-infrared photometry of a fraction of the sample in three separate passbands (1.25, 1.65 and 2.2 microns) allows us to study via colour-colour and colour-magnitude diagrams, the combined effects of both the intrinsic properties of the sources and the overlaying extinction which, at near-infrared wavelengths, is obviously considerably smaller than in the optical. Added to this, such diagrams and other basic criteria were used to determine which stars are members of the embedded young stellar population, i.e. separating the young PMS stars from the population of "normal" background/foreground main sequence stars and giants. Additionally, high-resolution molecular line observations of the Serpens Nebula by White et al. (1995) were used to evaluate the extinction through each part of the cloud and allowed us to construct the dereddened K luminosity function of the cluster. To investigate the nature of the underlying Interstellar Mass Function (IMF), we calculated models which predict the evolution of the luminosity function of a cluster of PMS stars using the half-gaussian form of the Miller-Scalo IMF (Miller and Scalo 1979) and the slope of the mass-K luminosity relation as derived from transformed PMS tracks at each age and mass (d'Antona and Mazzitelli 1994). We then compared these models with the Serpens KLF to place constraints on the star-formation history and we found that a second

  4. 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

  5. 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.

  6. 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).

  7. OTELO SURVEY: DEEP BVRI BROADBAND PHOTOMETRY OF THE GROTH STRIP. II. OPTICAL PROPERTIES OF X-RAY EMITTERS

    SciTech Connect

    Povic, M.; Perez GarcIa, A. M.; Bongiovanni, A.; Castaneda, H.; Lorenzo, M. Fernandez; Lara-Lopez, M. A.; Sanchez-Portal, M.; Alfaro, E.; Gallego, J.; Gonzalez-Serrano, J. I.; Gonzalez, J. J. E-mail: miguel.sanchez@sciops.esa.in

    2009-11-20

    The Groth field is one of the sky regions that will be targeted by the OSIRIS Tunable Filter Emission Line Object survey in the optical 820 nm and 920 nm atmospheric windows. In the present paper, public Chandra X-ray data with total exposure time of 200 ks are analyzed and combined with optical broadband data of the Groth field, in order to study a set of optical structural parameters of the X-ray emitters and its relation with X-ray properties. To this aim, we processed the raw, public X-ray data using the Chandra Interactive Analysis of Observations, and determined and analyzed different structural parameters, in order to produce a morphological classification of X-ray sources. We present the morphology of 340 X-ray emitters with optical counterpart detected. Objects have been classified by X-ray type using a diagnostic diagram relating X-ray-to-optical ratio (X/O) to hardness ratio. We did not find any clear correlation between X-ray and morphological types. We analyzed the angular clustering of X-ray sources with optical counterpart using two-point correlation functions. A significant positive angular clustering was obtained from a preliminary analysis of four subsamples of the X-ray sources catalog. The clustering signal of the optically extended counterparts is similar to that of strongly clustered populations like red and very red galaxies, suggesting that the environment plays an important role in active galactic nuclei phenomena. Finally, we combined optical structural parameters with other X-ray and optical properties, and we confirmed an anticorrelation between the X/O ratio and the Abraham concentration index, which might suggest that early-type galaxies have lower Eddington rates than those of late-type galaxies.

  8. 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.

  9. Asteroid Maps From Photometry And Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Kaasalainen, Mikko; Marchis, F.; Carry, B.

    2007-10-01

    While disk-integrated photometry is the main source of information on most asteroids, adaptive optics can provide some disk-resolved data on many larger (main-belt) asteroids. Asteroid models from lightcurve inversion agree well with the obtained AO images (Marchis et al. 2006, Icarus 185,39), but even more detailed models can be obtained by combining the two sources in inversion. In addition to giving more detail to existing models, the approach can also be used to obtain models of asteroids for which the photometric data are yet insufficient alone. This also helps to calibrate the inversion and deconvolution processes related to the separate sources; e.g., whether features apparently revealed by AO post-processing are real or artificial. We present some examples and discuss the resolution level of topographic detail in the resulting models. Hundreds of asteroids can be mapped in this way in the near future.

  10. A Rest-frame Optical View on z ~ 4 Galaxies. I. Color and Age Distributions from Deep IRAC Photometry of the IUDF10 and GOODS Surveys

    NASA Astrophysics Data System (ADS)

    Oesch, P. A.; Labbé, I.; Bouwens, R. J.; Illingworth, G. D.; Gonzalez, V.; Franx, M.; Trenti, M.; Holden, B. P.; van Dokkum, P. G.; Magee, D.

    2013-08-01

    We present a study of rest-frame UV-to-optical color distributions for z ~ 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 ~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 β and Balmer break colors (J 125 - [4.5]) as a function of rest-frame optical luminosity (using [4.5] to avoid optical emission lines). We find that galaxies at Mz < -21.5 (roughly corresponding to L^*_{z\\sim 4}) are significantly redder than their lower luminosity counterparts. The UV continuum slopes and the J 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 108.5 to 109 yr, with a dispersion of ~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 Mz < -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. Based on data obtained with the Hubble Space Telescope operated by AURA, Inc. for NASA under contract NAS5-26555. Based on observations with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

  11. Deep photometry and integral magnitudes of 8 nearby galaxies

    NASA Astrophysics Data System (ADS)

    Georgiev, Ts. B.

    2016-02-01

    We estimated integral magnitudes of galaxies trying to include the contribution of the brightest part of their halos. We performed surface photometry based on (i) concentric elliptical rims, corresponding to the peripheral ellipticity of the image, (ii) median estimation of the mean value of the rim pixels, (iii) apparent radial brightness profiles, corresponding to the rim medians, and (iv) magnitude curves of growth, derived by numerical integrations of the apparent rim profiles, without preliminary background estimation and removal. Furthermore, we used the magnitude curves of growth to determine the integral magnitudes (limited by size and deepness of our frames) and compared them with the total magnitudes in the data base HyperLeda. Also, we used the rim-profiles to estimate the background level far enough from the galaxy center and we build (here—only for trial) the intrinsic radial profiles (with background removal). We apply this photometry on 8 nearby galaxies, observed with CCD in the system BVRC IC by the 50 cm Schmidt telescope of the Rozhen NAO in 2003-2004. We build radial profiles which occur to be as average 1.8 times (1.2-2.5 times) larger than in data base NED and of integral brightness that occurs to be about 1.4 times (1.2-1.7 times) higher than in data base HyperLeda. The relative brightness additions, found here, correlate with the color index and anti-correlate with the luminosity of the galaxy.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Millisecond optical photometry of the DQ Herculis objects

    NASA Technical Reports Server (NTRS)

    Imamura, James N.; Steiman-Cameron, Thomas Y.

    1988-01-01

    The results of millisecond optical photometry of the DQ Herculis stars EX Hya, H2252-035, V1223 Sgr, and AE Aqr obtained at the Las Campanas Observatory and Cerro Tololo Inter-American Observatory during the years 1985, 1986, and 1987 are reported. The data for coherent and incoherent features are searched for. Coherent features (other than those previously known) were not detected for frequencies between 0.1 and 250 Hz at 4-sigma upper limits of 0.05-0.4 percent. Evidence is not found for 1-3 s, quasi-coherent features. Such features have been detected in the optical emission of the AM Her objects AN UMa, EF Eri, and E1405-451. Because of the similarities between AM Her and DQ Her objects, it was suggested that such quasi-coherent features might also be found in the DQ Her objects.

  17. DEEP HST/ACS PHOTOMETRY OF THE M81 HALO

    SciTech Connect

    Durrell, Patrick R.; Sarajedini, Ata; Chandar, Rupali

    2010-08-01

    We present a deep color-magnitude diagram (CMD) for individual stars in the halo of the nearby spiral galaxy M81, at a projected distance of 19 kpc, based on data taken with the Advanced Camera for Surveys on the Hubble Space Telescope (HST). The CMD reveals a red giant branch (RGB) that is narrow and fairly blue, and a horizontal branch that has stars that lie mostly redward of the RR Lyrae instability strip. We derive a mean metallicity of [M/H] = -1.15 {+-} 0.11 and age of 9 {+-} 2 Gyr for the dominant population in our field, from the shape of the RGB, the magnitude of the red clump, and the location of the RGB bump. We compare our metallicity and age results with those found previously for stars in different locations within M81 and in the spheroids of other nearby galaxies.

  18. 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

  19. 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.

  20. Optical Photometry of GRB 021004: The First Month

    NASA Astrophysics Data System (ADS)

    Holland, Stephen T.; Weidinger, Michael; Fynbo, Johan P. U.; Gorosabel, Javier; Hjorth, Jens; Pedersen, Kristian; Méndez Alvarez, Javier; Augusteijn, Thomas; Castro Cerón, J. M.; Castro-Tirado, Alberto; Dahle, Håkon; Egholm, M. P.; Jakobsson, Páll; Jensen, Brian L.; Levan, Andrew; Møller, Palle; Pedersen, Holger; Pursimo, Tapio; Ruiz-Lapuente, Pilar; Thomsen, Bjarne

    2003-05-01

    We present UBVRCIC photometry of the optical afterglow of the gamma-ray burst GRB 021004 taken at the Nordic Optical Telescope between approximately 8 hours and 30 days after the burst. These data are combined with an analysis of the 87 ks Chandra X-ray observations of GRB 021004 taken at a mean epoch of 33 hr after the burst to investigate the nature of this GRB. We find an intrinsic spectral slope at optical wavelengths of βUH=0.39+/-0.12 and an X-ray slope of βX=0.94+/-0.03. There is no evidence for color evolution between 8.5 hr and 5.5 days after the burst. The optical decay becomes steeper approximately 5 days after the burst. This appears to be a gradual break due to the onset of sideways expansion in a collimated outflow. Our data suggest that the extragalactic extinction along the line of sight to the burst is between AV~0.3 and 0.5 and has an extinction law similar to that of the Small Magellanic Cloud. The optical and X-ray data are consistent with a relativistic fireball with the shocked electrons being in the slow cooling regime and having an electron index of p=1.9+/-0.1. The burst occurred in an ambient medium that is homogeneous on scales larger than approximately 1018 cm but inhomogeneous on smaller scales. The mean particle density is similar to what is seen for other bursts (0.1 cm-3<~n<~100 cm-3). Our results support the idea that the brightening seen at approximately 0.1 days was due to interaction with a clumpy ambient medium within 1017-1018 cm of the progenitor. The agreement between the predicted optical decay and that observed approximately 10 minutes after the burst suggests that the physical mechanism controlling the observed flux at t~10 minutes is the same as the one operating at t>0.5 days. Based on observations taken with the Nordic Optical Telescope, operated on the island of Santa Miguel de la Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden in the Spanish Observatorio del Roque de los Muchachos of the Instituto de

  1. Deep space optical communications experiment

    NASA Technical Reports Server (NTRS)

    Kinman, P.; Katz, J.; Gagliardi, R.

    1983-01-01

    An optical communications experiment between a deep space vehicle and an earth terminal is under consideration for later in this decade. The experimental link would be incoherent (direct detection) and would employ two-way cooperative pointing. The deep space optical transceiver would ride piggyback on a spacecraft with an independent scientific objective. Thus, this optical transceiver is being designed for minimum spacecraft impact - specifically, low mass and low power. The choices of laser transmitter, coding/modulation scheme, and pointing mechanization are discussed. A representative telemetry link budget is presented.

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Fast Optical Photometry of V404 Cyg at the MDM Observatory

    NASA Astrophysics Data System (ADS)

    Terndrup, D.; Wagner, R. M.; Starrfield, S.

    2015-06-01

    We obtained continuous fast differential optical photometry of V404 Cyg with the 1.3 m McGraw-Hill Telescope of the MDM Observatory on Kitt Peak on the nights of 2015 June 19.220-19.474, 20.194-20.472, 21.199-21.460, and 22.188-22.421 UT.

  8. 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.

  9. 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.

  10. Deep Washington Photometry of Inconspicuous Star Cluster Candidates in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    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.

  11. 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

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

    NASA Astrophysics Data System (ADS)

    Vader, J. Patricia; Chaboyer, Brian

    1994-10-01

    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 r1/4 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 r1/4 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 merger

  13. Galaxy And Mass Assembly (GAMA): 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.; Cluver, M.; Davies, L. J. M.; 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.

    2016-04-01

    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 normalisation, 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 dataset 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 datasets. Nonetheless, 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 dataset. 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.

  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. 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).

  16. Accurate PSF-matched photometry and photometric redshifts for the extreme deep field with the Chebyshev-Fourier functions

    NASA Astrophysics Data System (ADS)

    Jiménez-Teja, Y.; Benítez, N.; Molino, A.; Fernandes, C. A. C.

    2015-10-01

    Photometric redshifts, which have become the cornerstone of several of the largest astronomical surveys like PanStarrs, DES, J-PAS and LSST, require precise measurements of galaxy photometry in different bands using a consistent physical aperture. This is not trivial, due to the variation in the shape and width of the point spread function (PSF) introduced by wavelength differences, instrument positions and atmospheric conditions. Current methods to correct for this effect rely on a detailed knowledge of PSF characteristics as a function of the survey coordinates, which can be difficult due to the relative paucity of stars tracking the PSF behaviour. Here we show that it is possible to measure accurate, consistent multicolour photometry without knowing the shape of the PSF. The Chebyshev-Fourier functions (CHEFs) can fit the observed profile of each object and produce high signal-to-noise integrated flux measurements unaffected by the PSF. These total fluxes, which encompass all the galaxy populations, are much more useful for galaxy evolution studies than aperture photometry. We compare the total magnitudes and colours obtained using our software to traditional photometry with SEXTRACTOR, using real data from the COSMOS survey and the Hubble Ultra-Deep Field (HUDF). We also apply the CHEF technique to the recently published eXtreme Deep Field (XDF) and compare the results to those from COLORPRO on the HUDF. We produce a photometric catalogue with 35 732 sources (10 823 with signal-to-noise ratio ≥5), reaching a photometric redshift precision of 2 per cent due to the extraordinary depth and wavelength coverage of the eXtreme Deep Field images.

  17. Deep CCD Photometry and RR Lyrae Survey for the Outer-Halo Globular Cluster NGC 6229

    NASA Astrophysics Data System (ADS)

    Catelan, M.; Borissova, J.; Spassova, N.; Ferraro, F. R.; Buonanno, R.; Sweigart, A. V.

    1997-12-01

    Deep BV CCD photometry for a large field covering the outer-halo Galactic globular cluster NGC 6229 is presented. For the first time, a color-magnitude diagram (CMD) reaching below the main-sequence turnoff has been obtained for this cluster. Previous results regarding the overall morphology of the horizontal and giant branches are confirmed. In addition, several candidate blue straggler stars are identified. However, a preliminary analysis of the cluster's CMD suggests that the putative extreme horizontal branch population suggested by Borissova et al. (1997, AJ, 113, 692) may not be present. Unfortunately, the innermost cluster regions could not be studied due to crowding. Comparison of the cluster CMD locus with the latest isochrones from VandenBerg (1997, private communication) is also presented, as is a study of the cluster age relative to a few well-studied reference globulars, using both the ``horizontal" and ``vertical" methods. We also report on an investigation of the variable stars in NGC 6229. We obtained new light curves and re-derived the periods, amplitudes and mean V and B-V magnitudes for 17 RR Lyrae stars listed in Sawyer Hogg's (1973, Publ. David Dunlap Obs., 3, No. 6) catalog. We obtained the first light curves for the RR Lyrae candidates No. 155 and No. 88 (Carney et al. 1991, AJ, 101, 1699), and confirm variability of their star No. 134, as well as of the RR Lyrae stars V3, V8 and V12 suspected by Borissova et al. (1997). A search for variable stars in our 5 x 5 arcmin field does not lead to any new variable candidates.

  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. The MIUSCAT stellar population models: constraints from optical photometry

    NASA Astrophysics Data System (ADS)

    Ricciardelli, E.; Vazdekis, A.; Cenarro, A. J.; Falcón-Barroso, J.

    2013-05-01

    We present the spectral extension of our stellar population synthesis models based on the MILES and CaT empirical stellar spectral libraries. For this purpose we combine these two libraries with the Indo-US to construct composite stellar spectra to feed our models. The spectral energy distributions (SEDs) computed with these models and the originally published models are combined to construct composite SEDs for single-age, single-metallicity stellar populations (SSPs) covering the range λλ3465 -- 9469 Å at resolution FWHM =2.51 Å. We also show a comprehensive comparison of the MIUSCAT models with photometric data of globular clusters and early-type galaxies. The models compare remarkably well with the integrated colours of Milky Way globular clusters in the optical range. On the other hand we find that the colour relations of nearby early-type galaxies are still a challenge for present-day stellar population synthesis models. We investigate a number of possible explanations and establish the importance of α-enhanced models to bring down the discrepancy with observations.

  1. Bayesian High-redshift Quasar Classification from Optical and Mid-IR Photometry

    NASA Astrophysics Data System (ADS)

    Richards, Gordon T.; Myers, Adam D.; Peters, Christina M.; Krawczyk, Coleman M.; Chase, Greg; Ross, Nicholas P.; Fan, Xiaohui; Jiang, Linhua; Lacy, Mark; McGreer, Ian D.; Trump, Jonathan R.; Riegel, Ryan N.

    2015-08-01

    We identify 885,503 type 1 quasar candidates to i≲ 22 using the combination of optical and mid-IR photometry. Optical photometry is taken from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III/BOSS), while mid-IR photometry comes from a combination of data from the Wide-field Infrared Survey Explorer (WISE) “AllWISE” data release and several large-area Spitzer Space Telescope fields. Selection is based on a Bayesian kernel density algorithm with a training sample of 157,701 spectroscopically confirmed type 1 quasars with both optical and mid-IR data. Of the quasar candidates, 733,713 lack spectroscopic confirmation (and 305,623 are objects that we have not previously classified as photometric quasar candidates). These candidates include 7874 objects targeted as high-probability potential quasars with 3.5\\lt z\\lt 5 (of which 6779 are new photometric candidates). Our algorithm is more complete to z\\gt 3.5 than the traditional mid-IR selection “wedges” and to 2.2\\lt z\\lt 3.5 quasars than the SDSS-III/BOSS project. Number counts and luminosity function analysis suggest that the resulting catalog is relatively complete to known quasars and is identifying new high-z quasars at z\\gt 3. This catalog paves the way for luminosity-dependent clustering investigations of large numbers of faint, high-redshift quasars and for further machine-learning quasar selection using Spitzer and WISE data combined with other large-area optical imaging surveys.

  2. 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.

  3. ASPIN: Research project on near-Earth asteroid photometry in frame of the ISON optical network

    NASA Astrophysics Data System (ADS)

    Molotov, Igor; Inasaridze, Raguli; Elenin, Leonid; Krugly, Yurij; Rumyantsev, Vasilij; Namkhai, Tungalag; Schmalz, Sergei; Tsogt-Ochir, Shijirbayar

    International Scientific Optical Network (ISON) represents one of largest systems specializing in observation of space objects. The main goal of project is observations of space debris. As an additional task the regular photometry of near-Earth asteroids (NEAs) is carried out using the network’s telescopes with apertures from 0.4 m up to 2.6 m (ASPIN project - Asteroid Search and Photometry Initiative). The photometry is aimed at getting lightcurves of asteroids for solving different tasks concerning with physical properties of these celestial bodies. The lightcurves have been obtained with a typical photometric accuracy of 0.01-0.03 mag. The main purpose of the observations is to study characteristics of asteroids such as rotation period, size and shape of the body, surface composition and other. It is expected to detect an influence of the YORP effect. Special attention is paid to the detection of binary asteroids. During 2013 the photometric observations have been carried out at 12 observatories during more than 250 nights which have been allowed to obtain the data on 40 NEAs as well as 15 main-belt asteroids. In result the rotation periods have been determined for 8 NEAs in the first time and refined for 10 NEAs. Two binary systems were discovered. Lightcurves of 11 main-belt asteroids with diameters less than 10 km (binary systems or members of small clusters) were obtained. Several of the observed asteroids were radar targets - between them the NEA (367943) Duende (or 2012 DA14), which was approached to the Earth in day of falling the Chelyabinsk meteor on February 23, 2013. The obtained results will be presented and perspectives of NEA photometry with ISON telescopes will be discussed.

  4. A Recalibration of Optical Photometry: Tycho-2, Strömgren, and Johnson Systems

    NASA Astrophysics Data System (ADS)

    Maíz Apellániz, J.

    2006-02-01

    I use high-quality Hubble Space Telescope (HST) spectrophotometry to analyze the calibration of three popular optical photometry systems: Tycho-2 BT and VT, Strömgren uvby, and Johnson UBV. For Tycho-2, I revisit the analysis of an earlier paper to include the new recalibration of grating/aperture corrections, vignetting, and charge transfer inefficiency effects produced by the Space Telescope Imaging Spectrograph group and to consider the consequences of both random and systematic uncertainties. The new results reaffirm the good quality of both the Tycho-2 photometry and the HST spectrophotometry but yield a slightly different value for ZPBT-VT of 0.033+/-0.001 (random) +/-0.005 (systematic) mag. For the Strömgren v, b, and y filters I find that the published sensitivity curves are consistent with the available photometry and spectrophotometry, and I derive new values for the associated ZPb-y and ZPm1. The same conclusion is drawn for the Johnson B and V filters and the associated ZPB-V. The situation is different for the Strömgren u and the Johnson U filters. There I find that the published sensitivity curves yield results that are inconsistent with the available photometry and spectrophotometry, likely caused by an incorrect treatment of atmospheric effects on the short-wavelength end. I reanalyze the data to produce new average sensitivity curves for those two filters and new values for ZPc1 and ZPU-B. The new computation of synthetic U-B and B-V colors uses a single B sensitivity curve, which eliminates the previous unphysical existence of different definitions for each color. Finally, I find that if one uses values from the literature for which uncertainties are not given, reasonable estimates for these are 1%-2% for Strömgren b-y, m1, and c1 and 2%-3% for Johnson B-V and U-B. The use of the results in this paper should lead to a significant reduction of systematic errors when comparing synthetic photometry models with real colors and indices.

  5. 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.

  6. 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.

  7. 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.

  8. Compact Deep-Space Optical Communications Transceiver

    NASA Technical Reports Server (NTRS)

    Roberts, W. Thomas; Charles, Jeffrey R.

    2009-01-01

    Deep space optical communication transceivers must be very efficient receivers and transmitters of optical communication signals. For deep space missions, communication systems require high performance well beyond the scope of mere power efficiency, demanding maximum performance in relation to the precious and limited mass, volume, and power allocated. This paper describes the opto-mechanical design of a compact, efficient, functional brassboard deep space transceiver that is capable of achieving megabyte-per-second rates at Mars ranges. The special features embodied to enhance the system operability and functionality, and to reduce the mass and volume of the system are detailed. System tests and performance characteristics are described in detail. Finally, lessons learned in the implementation of the brassboard design and suggestions for improvements appropriate for a flight prototype are covered.

  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

    2016-01-01

    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

  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 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.

  13. 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.

  14. 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.

  15. 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.

  16. Optical photometry and spectroscopy of the 1987A-like supernova 2009mw

    NASA Astrophysics Data System (ADS)

    Takáts, K.; Pignata, G.; Bersten, M.; Rojas Kaufmann, M. L.; Anderson, J. P.; Folatelli, G.; Hamuy, M.; Stritzinger, M.; Haislip, J. B.; LaCluyze, A. P.; Moore, J. P.; Reichart, D.

    2016-08-01

    We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our $BVRI$ and $g'r'i'z'$ photometry covers 167 days of evolution, including the rise to the light curve maximum, and ends just after the beginning of the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup, and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated via hydrodynamical modelling, yielding an explosion energy of $1$ foe, a pre-SN mass of $19\\,{\\rm M_{\\odot}}$, a progenitor radius as $30\\,{\\rm R_{\\odot}}$ and a $^{56}$Ni mass as $0.062\\,{\\rm M_{\\odot}}$. These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with slightly sub-solar metallicty.

  17. Optical photometry and spectroscopy of the 1987A-like supernova 2009mw

    NASA Astrophysics Data System (ADS)

    Takáts, K.; Pignata, G.; Bersten, M.; Rojas Kaufmann, M. L.; Anderson, J. P.; Folatelli, G.; Hamuy, M.; Stritzinger, M.; Haislip, J. B.; LaCluyze, A. P.; Moore, J. P.; Reichart, D.

    2016-08-01

    We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our BVRI and g'r'i'z' photometry covers 167 d of evolution, including the rise to the light-curve maximum, and ends just after the beginning of the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated through hydrodynamical modelling, and yield an explosion energy of 1 foe, a pre-SN mass of 19 M⊙, a progenitor radius of 30 R⊙ and a 56Ni mass of 0.062 M⊙. These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with a slightly subsolar metallicty.

  18. 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. PMID:26138853

  19. 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.

  20. 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

  1. Deep-Space Optical Terminals (DOT)

    NASA Technical Reports Server (NTRS)

    Hemmati, H.; Farr, W. H.; Biswas, A.; Birnbaum, K. M.; Roberts, W. T.; Quirk, K.; Townes, S.

    2011-01-01

    A conceptual design study titled Deep-Space Optical Terminals was recently completed for an optical communication technology demonstration from Mars in the 2018 time frame. We report on engineering trades for the entire system, and for individual subsystems including the flight terminal, the ground receiver and the ground transmitter. A point design is described to meet the requirement for greater than 0.25 Gb/s downlink from the nearest distance to Mars of 0.42 AU with a maximum mass and power allocation of 40 kg and 110 W. Furthermore, the concept design addresses link closure at the farthest Mars range of 2.7 AU. Maximum uplink data-rate of 0.3 Mb/s and ranging with 30 cm precision are also addressed.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2004-01-01

    The NASA-JPL Deep Space 1 Mission (DS1) encountered the short-period Jupiter-family Comet 19P/Borrelly on September 22, 2001, about 8 days after perihelion. DS1's payload contained a remote-sensing package called MICAS (Miniature Integrated Camera Spectrometer) that included a 1024 square CCD and a near IR spectrometer with ˜12 nm resolution. Prior to its closest approach of 2171 km, the remote-sensing package on the spacecraft obtained 25 CCD images of the comet and 45 near-IR spectra (L. Soderblom et al., 2002, Science 296, 1087-1091). These images provided the first close-up view of a comet's nucleus sufficiently unobscured to perform quantitative photometric studies. At closest approach, corresponding to a resolution of 47 meters per pixel, the intensity of the coma was less than 1% of that of the nucleus. An unprecedented range of high solar phase angles (52-89 degrees), viewing geometries that are in general attainable only when a comet is active, enabled the first quantitative and disk resolved modeling of surface photometric physical parameters, including the single particle phase function and macroscopic roughness. The disk-integrated geometric albedo of Borrelly's nucleus is 0.029±0.006, comparable to the dark hemisphere of Iapetus, the lowest albedo C-type asteroids, and the uranian rings. The Bond albedo, 0.009±0.002, is lower than that of any Solar System object measured. Such a low value may enhance the heating of the nucleus and sublimation of volatiles, which in turn causes the albedo to decrease even further. A map of normal reflectance of Borrelly shows variations far greater than those seen on asteroids. The two main terrain types, smooth and mottled, exhibit mean normal reflectances of 0.03 and 0.022. The physical photometric parameters of Borrelly's nucleus are typical of other small dark bodies, particularly asteroids, except preliminary modeling results indicate its regolith may be substantially fluffier. The nucleus exhibits significant

  4. 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.

  5. 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.

  6. Adaptive optics for daytime deep space laser communications to Mars

    NASA Technical Reports Server (NTRS)

    Wilson, Keith E.; Wright, Malcolm; Lee, Shinkhak; Troy, Mitchell

    2005-01-01

    This paper describes JPL research in adaptive optics (AO) to reduce the daytime background noise on a Mars-to-Earth optical communications link. AO can reduce atmosphere-induced wavefront aberrations, and enable single mode receiver operation thereby buying back margin in the deep space optical communications link.

  7. Optical and NIR Photometry of the Interacting Dwarf Galaxies IIZw70 / IIZw71 (Poster)

    NASA Astrophysics Data System (ADS)

    Papaderos, P.; Noeske, K. G.; Cairós, L. M.; Vílchez, J. M.; Fricke, K. J.

    We obtained deep optical and NIR images of the pair of blue compact dwarf (BCD) galaxies II Zw 70 and II Zw 71 in order to study the effects of interaction on the structural properties of their stellar low-surface-brightness (LSB) component. We find that within their Holmberg radius the interacting BCDs under study do not differ significantly in terms of the central surface brightness and exponential scale length of their LSB hosts from typical iE/nE systems. In the faint outskirts (26.2 < mu_B [mag arcsec^-2^] < 28.5) of both systems, however, the present data reveal conspicuous morphological distortions, most notably an extended feature protruding as far as ~9 kpc from the starburst region of II Zw 70 in the direction of II Zw 71. The relatively blue colors of this stellar extension, together with its apparent spatial coincidence with the massive HI streamer connecting the dwarf galaxies, are consistent with the hypothesis that it originates from recent star formation within the gaseous halo of II Zw 70, rather than from stellar matter torn out of the LSB host of the BCD during the interaction.The results presented here support the view that important signatures of the dynamical response and secular evolution of the stellar LSB component in interacting dwarf galaxies can be found in their very faint outskirts.

  8. 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.

  9. 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.

  10. Space Station-based deep-space optical communication experiments

    NASA Technical Reports Server (NTRS)

    Chen, Chien-Chung; Schwartz, Jon A.

    1988-01-01

    A series of three experiments proposed for advanced optical deep-space communications is described. These proposed experiments would be carried out aboard the Space Station to test and evaluate the capability of optical instruments to conduct data communication and spacecraft navigation for deep-space missions. Techniques for effective data communication, precision spacecraft ranging, and accurate angular measurements will be developed and evaluated in a spaceborne environment.

  11. 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. PMID:21045892

  12. Millimagnitude Optical Photometry for the Transiting Planetary Candidate OGLE-TR-109

    NASA Astrophysics Data System (ADS)

    Fernández, José Miguel; Minniti, Dante; Pietrzynski, Grzegorz; Gieren, Wolfgang; Ruíz, María Teresa; Zoccali, Manuela; Udalski, Andrzej; Szeifert, Thomas

    2006-08-01

    We present precise V-band photometry for the low-amplitude transit candidate star OGLE-TR-109. This is an extreme case among the transiting candidates found by the OGLE group because of the early spectral type of the star (F0 V), the low transit amplitude (AI=0.008 mag), and the very short period (P=0.58909 days) of the orbiting companion. Using difference image photometry, we are able to achieve millimagnitude errors in the individual data points. One transit of this star is well defined in our light curve. This confirms the OGLE detection and rules out the possibility of a false positive. The measurement of this transit allows us to refine the transit amplitude (AV=0.006+/-0.001 mag) and the ephemerides for this interesting system, as well as the radius of the possible orbiting companion (RP=0.90RJ+/-0.09RJ) and the inclination of the orbit (i=77deg+/-5deg). Two other transits observed at lower S/N confirm the period of this system measured by OGLE. There is no evidence for a blend of the F-type main-sequence star with a redder eclipsing binary or for secondary transits in the present observations. The absence of ellipsoidal modulation in the light curve of the primary rules out a low-mass star companion or brown dwarf with M>14MJ+/-8MJ. The remaining possibilities for OGLE-TR-109 are a blend between the F-type star and a binary with a bluer primary star, or a new transiting extrasolar planet. Based on observations collected with the Very Large Telescope at Paranal Observatory [ESO Program 075.C-0427(A), J. M. F. and D. M. visiting observers].

  13. 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.

  14. Quasi-stellar objects in the ALHAMBRA survey. I. Photometric redshift accuracy based on 23 optical-NIR filter photometry

    NASA Astrophysics Data System (ADS)

    Matute, I.; Márquez, I.; Masegosa, J.; Husillos, C.; del Olmo, A.; Perea, J.; Alfaro, E. J.; Fernández-Soto, A.; Moles, M.; Aguerri, J. A. L.; Aparicio-Villegas, T.; Benítez, N.; Broadhurst, T.; Cabrera-Cano, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; Infante, L.; González Delgado, R. M.; Martínez, V. J.; Molino, A.; Prada, F.; Quintana, J. M.

    2012-06-01

    Context. Even the spectroscopic capabilities of today's ground and space-based observatories can not keep up with the enormous flow of detections (>105 deg-2) unveiled in modern cosmological surveys as: i) would be required enormous telescope time to perform the spectroscopic follow-ups and ii) spectra remain unattainable for the fainter detected population. In the past decade, the typical accuracy of photometric redshift (photo-z) determination has drastically improved. Nowdays, it has become a perfect complement to spectroscopy, closing the gap between photometric surveys and their spectroscopic follow-ups. The photo-z precision for active galactic nuclei (AGN) has always lagged behind that for the galaxy population owing to the lack of proper templates and their intrinsic variability. Aims: Our goal is to characterize the ability of the Advanced Large, Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey in assigning accurate photo-z's to broad-line AGN (BLAGN) and quasi-stellar objects (QSOs) based on their ALHAMBRA very-low-resolution optical-near-infrared (NIR) spectroscopy. This will serve as a benchmark for any future compilation of ALHAMBRA selected QSOs and the basis for the statistical analysis required to derive luminosity functions up to z ~ 5. Methods: We selected a sample of spectroscopically identified BLAGN and QSOs and used a library of templates (including the SEDs of AGN and both normal and starburst galaxies, as well as stars) to fit the 23 photometric data points provided by ALHAMBRA in the optical and NIR (20 medium-band optical filters plus the standard JHKs). Results: We find that the ALHAMBRA photometry is able to provide an accurate photo-z and spectral classification for ~88% of the 170 spectroscopically identified BLAGN/QSOs over 2.5 deg2 in different areas of the survey and brighter than m678 = 23.5 (equivalent to rSLOAN ~ 24.0). The derived photo-z accuracy is below 1% and is comparable to the most recent results in

  15. Deep seawater inherent optical properties in the Southern Ionian Sea

    NASA Astrophysics Data System (ADS)

    Riccobene, G.; Capone, A.; Aiello, S.; Ambriola, M.; Ameli, F.; Amore, I.; Anghinolfi, M.; Anzalone, A.; Avanzini, C.; Barbarino, G.; Barbarito, E.; Battaglieri, M.; Bellotti, R.; Beverini, N.; Bonori, M.; Bouhadef, B.; Brescia, M.; Cacopardo, G.; Cafagna, F.; Caponetto, L.; Castorina, E.; Ceres, A.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coniglione, R.; Cordelli, M.; Costa, M.; Cuneo, S.; D'Amico, A.; de Bonis, G.; de Marzo, C.; de Rosa, G.; de Vita, R.; Distefano, C.; Falchini, E.; Fiorello, C.; Flaminio, V.; Fratini, K.; Gabrielli, A.; Galeotti, S.; Gandolfi, E.; Grimaldi, A.; Habel, R.; Leonora, E.; Lonardo, A.; Longo, G.; Lo Presti, D.; Lucarelli, F.; Maccioni, E.; Margiotta, A.; Martini, A.; Masullo, R.; Megna, R.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Musumeci, M.; Nicolau, C. A.; Orlando, A.; Osipenko, M.; Osteria, G.; Papaleo, R.; Pappalardo, V.; Petta, C.; Piattelli, P.; Raffaelli, F.; Raia, G.; Randazzo, N.; Reito, S.; Ricco, G.; Ripani, M.; Rovelli, A.; Ruppi, M.; Russo, G. V.; Russo, S.; Russo, S.; Sapienza, P.; Sedita, M.; Schuller, J.-P.; Shirokov, E.; Simeone, F.; Sipala, V.; Spurio, M.; Taiuti, M.; Terreni, G.; Trasatti, L.; Urso, S.; Valente, V.; Vicini, P.

    2007-02-01

    The NEMO (NEutrino Mediterranean Observatory) Collaboration has been carrying out since 1998 an evaluation programme of deep sea sites suitable for the construction of the future Mediterranean km3 Čerenkov neutrino telescope. We investigated the seawater optical and oceanographic properties of several deep sea marine areas close to the Italian Coast. Inherent optical properties (light absorption and attenuation coefficients) have been measured as a function of depth using an experimental apparatus equipped with standard oceanographic probes and the commercial transmissometer AC9 manufactured by WETLabs. This paper reports on the visible light absorption and attenuation coefficients measured in deep seawater of a marine region located in the Southern Ionian Sea, 60 100 km SE of Capo Passero (Sicily). Data show that blue light absorption coefficient is about 0.015 m-1 (corresponding to an absorption length of 67 m) close to the one of optically pure water and it does not show seasonal variation.

  16. Ultra-deep Optical Spectroscopy with PMAS

    NASA Astrophysics Data System (ADS)

    Roth, M. M.; Fechner, T.; Wolter, D.; Kelz, A.; Becker, T.

    PMAS, the Potsdam Multi-Aperture Spectrophotometer, is a new integral field spectrograph in the optical, which is optimized for good transmission and high image quality from 350 nm to 1 mm. We present our plan to implement a CCD charge-shuffle mode to allow for beam switching with a very high degree of sky subtraction accuracy for faint object 3-D spectroscopy.

  17. Deep optical trap for cold alkaline-Earth atoms.

    PubMed

    Cruz, Luciano S; Sereno, Milena; Cruz, Flavio C

    2008-03-01

    We describe a setup for a deep optical dipole trap or lattice designed for holding atoms at temperatures of a few mK, such as alkaline-Earth atoms which have undergone only regular Doppler cooling. We use an external optical cavity to amplify 3.2 W from a commercial single-frequency laser at 532 nm to 523 W. Powers of a few kW, attainable with low-loss optics or higher input powers, allow larger trap volumes for improved atom transfer from magneto-optical traps. We analyze possibilities for cooling inside the deep trap, the induced Stark shifts for calcium, and a cancellation scheme for the intercombination clock transition using an auxiliary laser. PMID:18542375

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. A Glimpse of Optically Variable Galactic Bulge X-ray Sources: A Comparison of Mosaic-II and DECam Photometry

    NASA Astrophysics Data System (ADS)

    Johnson, Christopher Bradley; Hynes, Robert I.; Jonker, Peter; Torres, Manuel; Britt, Chris; Steeghs, Danny; Maccarone, Tom; Nelemans, Gijs; Greiss, Sandra; Baldwin, Austin

    2014-06-01

    We present optical photometry and spectroscopy of selected sources from the Galactic Bulge Survey (GBS) using the new DECam imager and the previous Mosaic-II imager on the 4m Blanco telescope at Cerro-Tololo Inter-American Observatory (CTIO). The goal of the GBS is to detect quiescent Low-Mass X-Ray Binaries (LMXB) and identify eclipsing systems for follow-up mass determination to test binary population models and to better determine black hole and neutron star mass distributions. We compare the light curves of spectroscopically intriguing sources with both instruments and show that the DECam observations demonstrate large improvements in sensitivity to short-period binary systems. Because of DECam's field of view of 2.2 degrees, our survey area can be covered in 4 pointings as opposed to 64 with Mosaic-II. This increased our sampling rate from 2-5 times to 28-56 times per target per night, which includes dithering. We find that combining 2x1 secs and 2x90 secs exposures over a two day observing run, we can detect targets between 12th and 23rd magnitude. Overall, we are finding that DECam is a superb instrument for detecting variability of sources in wide-field optical surveys. This work was supported by the National Science Foundation under Grant No. AST-0908789 and by NASA through Chandra Award Number AR3-14002X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.

  3. 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.

  4. The Optical-IR Color-Magnitude Sequence Around the Hydrogen Burning Mass Limit: Optical Photometry and Trigonometric Parallaxes for Nearby M and L Dwarfs

    NASA Astrophysics Data System (ADS)

    Dieterich, Sergio; Henry, T. J.; Hosey, A. D.; Jao, W.; Winters, J. G.; RECONS

    2012-01-01

    Accurate placement in an HR diagram is necessary for the characterization of any stellar, or substellar, population. Here we extend the coverage of optical/IR color-magnitude diagrams to provide a continuous sequence for stars like the Sun through the mid L spectral sub-types. We present new trigonometric parallaxes obtained at the CTIO 0.9m telescope through the RECONS (REsearch Consortium On Nearby Stars, www.recons.org) astrometry program, and new VRI photometry obtained at the CTIO 0.9m and SOAR 4m telescopes. We demonstrate how optical/IR color combinations, in particular (V-K), are useful in breaking the degeneracies in color-magnitude diagrams containing only IR colors. One of the key results of this work is a set of improved color-absolute magnitude relations that can be used to make accurate distance estimates for objects straddling the hydrogen-burning limit. We also discuss objects thought to be young, multiple, or metal poor based on their outlying locations in the sequence. This effort is supported by the NSF through grant AST-0908402, via observations made possible by the SMARTS Consortium, and is based in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Brazilian Ministry of Science and Technology, the U.S. National Optical Astronomy Observatory, the University of North Carolina at Chapel Hill, and Michigan State University.

  5. 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.

  6. Optical broad-band photometry and reference image for APMUKS(BJ) B215839.70-615403.9 / ASASSN-15lh from the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Melchior, Peter; Drlica-Wagner, Alexander; Bechtol, Keith; Rykoff, Eli; Hartley, William; Dark Energy Survey Collaboration

    2015-07-01

    We report optical broad-band photometry of the host galaxy APMUKS(BJ) B215839.70-615403.9 of SLSN ASASSN-15lh (ATel #7642; Dong et al., arXiv:1507.03010). The images were obtained using the DECam imager on the Blanco 4-m telescope at NOAO's Cerro Tololo Inter-American Observatory during Year-2 observations of the Dark Energy Survey (DES). A preliminary reduction of the images was performed by the DES Data Management pipeline (Mohr et al. 2012, SPIE Conference Series, 84510D; Desai et al. 2012, ApJ, 757, 83). The photometry was measured using SExtractor with additional calibration via stellar locus regression to provide magnitude zero points with 2-3% calibration uncertainty for point sources (relative to 2MASS) and mildly increased uncertainties for extended sources. We fit the DES g-r, r-i, and i-z colors to a red-sequence model from redMaPPer (Rykoff et al. 2014, ApJ, 785, 104) and obtain a redshift 0.25±0.02, consistent with the spectroscopic redshift of z = 0.2326 (ATel #7774). Fixed to that redshift, the host photometry is fully consistent with a red-sequence galaxy. We combine photometry from DES grizY with VHS NIR (ATel #7776) and WISE IR and fit a linear combination of single stellar populations with a variety of ages. We find that the fit is dominated by an old (5 Gyr) component, consistent with those of elliptical galaxies. We further compare with dusty SEDs taken from the latest set of templates in EAZY (Brammer, van Dokkum & Coppi, 2008, ApJ, 686, 1503). The combined host photometry is not well described by any of the dusty templates.

  7. The type 1a supernova 1986G in NGC 5128 - Optical photometry and spectra

    NASA Astrophysics Data System (ADS)

    Phillips, M. M.; Phillips, A. C.; Heathcote, S. R.; Blanco, V. M.; Geisler, D.; Hamilton, D.; Suntzeff, N. B.; Jablonski, F. J.; Steiner, J. E.; Cowley, A. P.; Schmidtke, P.; Wyckoff, S.; Hutchings, J. B.; Tonry, J.; Strauss, M. A.; Thorstensen, J. R.; Honey, W.; Maza, J.; Ruiz, M. T.; Landolt, A. U.; Uomoto, A.; Rich, R. M.; Grindlay, J. E.; Cohn, H.; Smith, H. A.; Lutz, J. H.; Lavery, R. J.; Saha, A.

    1987-07-01

    Optical light curves and spectra of the Type Ia supernova 1986G in NGC 5128 (Centaurus A) are presented. Although the spectral evolution closely resembled that of the more common "slower" photometric classes of Type Ia supernovae, subtle differences in the maximum-light spectra were detected. The expansion velocity of the photosphere of SN 1986G decreased rapidly at early phases. SN 1986G appears to have been heavily obscured by the dust lane of NGC 5128. This circumstances accounts for the strong interstellar-absorption lines of Ca II H and K and Na I D observed in the spectra as well as for features that the authors identify with the diffuse interstellar bands. SN 1986G provides graphic confirmation of the existence of intrinsic differences in the optical light curves and spectroscopic properties of Type Ia supernovae. Consequently, these objects must be used with considerable caution as cosmological standard candles. The authors derive a relative distance of DNGC 5128/DNGC 5055 = 0.39±0.04.

  8. 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.

  9. 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.

  10. Optics on a fractal surface and the photometry of the regoliths

    NASA Astrophysics Data System (ADS)

    Drossart, P.

    1993-05-01

    The light scattered by a rough surface is calculated in a model where the surface is simulated by a mathematical fractal of dimension (D(H) between 2 and 3) and fractal density in the projected area towards the observer rho(H) (rho(H) between 0 and 1). The reflectance on such a surface is calculated in the special case of a 'hemispherical' fractal, in both the geometric optics approximation and a more general diffraction regime. By using a two-parameter phase function (single scattering albedo omega-sub-0 and asymmetry parameter g-sub-0), and including multiple scattering, this four-parameter model is found to reproduce within a good accuracy the phase function of several classes of atmosphereless bodies in the solar system, in good agreement with previous photometric models. The main effect of the diffraction is to reduce the width of the opposition surge by roughly a factor of 2. Another prediction of the model is that the single-scattering contribution due to the fractal part of the surface can be reduced, for nonzero phase angle, to an arbitrarily small amount, for high enough fractal dimension and density. This effect could give a new interpretation of the strong opposition effect observed on some objects, and also of the very low brightness of many solar system bodies.

  11. Optical communications systems and technology for deep-space exploration

    NASA Technical Reports Server (NTRS)

    Lesh, James R.

    1989-01-01

    An account is given of architectural and implementational strategies for the creation of planetary and other deep-space optical communications networks, with a view to the developmental requirements of both planetary spacecraft subsystems and an earth-vicinity reception system. Attention is given to prospective technology-development challenges. An open-loop spatial acquisition process is defined, in conjunction with a terrestrial, large-aperture/low-cost 'photon bucket' optical reception telescopic system having an integral, axially-aligned tube-bundle sunshield. An efficient diode-pumped Nd:YAG laser is envisioned as the transmitter.

  12. Estimation and tracking for deep-space optical communications

    NASA Technical Reports Server (NTRS)

    Win, Moe Zaw

    1989-01-01

    The importance of pointing and tracking is demonstrated with current deep-space optical communications system concepts. Maximum-likelihood (ML), minimum square counting-error (MSCE), and maximum product (MP) estimation algorithms (or decision rules) are derived to estimate the location of the receiving station to subpixel resolution. Comparisons of the above algorithms are made, via Monte Carlo computer simulation, in terms of estimator's bias and variance. Optical communication link analyses are made for a typical earth-Mars scenario, to gain engineering insights. It is observed that both the ML rule and the MSCE rule perform better than the MP rule.

  13. An Array of Optical Receivers for Deep-Space Communications

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Chi-Wung; Srinivasan, Meera; Andrews, Kenneth

    2007-01-01

    An array of small optical receivers is proposed as an alternative to a single large optical receiver for high-data-rate communications in NASA s Deep Space Network (DSN). Because the telescope for a single receiver capable of satisfying DSN requirements must be greater than 10 m in diameter, the design, building, and testing of the telescope would be very difficult and expensive. The proposed array would utilize commercially available telescopes of 1-m or smaller diameter and, therefore, could be developed and verified with considerably less difficulty and expense. The essential difference between a single-aperture optical-communications receiver and an optical-array receiver is that a single-aperture receiver focuses all of the light energy it collects onto the surface of an optical detector, whereas an array receiver focuses portions of the total collected energy onto separate detectors, optically detects each fractional energy component, then combines the electrical signal from the array of detector outputs to form the observable, or "decision statistic," used to decode the transmitted data. A conceptual block diagram identifying the key components of the optical-array receiver suitable for deep-space telemetry reception is shown in the figure. The most conspicuous feature of the receiver is the large number of small- to medium-size telescopes, with individual apertures and number of telescopes selected to make up the desired total collecting area. This array of telescopes is envisioned to be fully computer- controlled via the user interface and prediction-driven to achieve rough pointing and tracking of the desired spacecraft. Fine-pointing and tracking functions then take over to keep each telescope pointed toward the source, despite imperfect pointing predictions, telescope-drive errors, and vibration caused by wind.

  14. Link Characterization for Deep-Space Optical Communications

    NASA Astrophysics Data System (ADS)

    Xie, H.; Heckman, D.; Breidenthal, J.

    2016-05-01

    We report the performance of candidate deep-space optical communication systems that would use a single optical ground station in conjunction with various space terminals. We considered three potential diameters of ground receive terminals (4μm, 8μm, and 12μm) and three potential ground transmit powers (1 kW, 5 kW, and 10 kW). Combinations of ground receive terminals, ground transmit terminals, and spacecraft terminals were assessed for data rate and data volume return, both uplink and downlink, and for uplink irradiance needed to enable downlink pointing. System performance was evaluated in the context of a set of 12 design reference missions described in a companion article in this volume. Link performance was evaluated using the Strategic Optical Link Tool, assuming clear weather conditions with conservative desert daytime turbulence. We compared the link performance achievable under our assumptions to the anticipated requirements associated with the design reference missions.

  15. 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.

  16. 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.

  17. 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.

  18. Multicolor Optical Photometry of the 2015 Eruption of Recurrent Nova M31N 1963-09c

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vrastil, J.; Wolf, M.; Kucakova, H.; Shafter, A. W.; Horst, J. C.; Rivera, D. I.

    2015-11-01

    We report additional multicolor photometry of the recurrent nova M31N 1963-09c (see ATel #8233, #8234, #8235, and CBAT TOCP) acquired with the 0.65-m telescope at Ondrejov and the Mount Laguna Observatory's 40-inch reflector.

  19. Late-time Optical Photometry of the 2015 Eruption of M31N 2008-12a

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.; Quimby, R.; Shafter, A. W.; Henze, M.; Darnley, M. J.; Kato, M.

    2015-09-01

    We report additional multicolor photometry of the most recent outburst of the remarkable recurrent nova M31N 2008-12a (ATel #7964, #7965, #7967, #7968, #7969, #7974) acquired with the 0.65-m telescope at Ondrejov and the Mount Laguna Observatory's 40-inch reflector.

  20. 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.

  1. 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.

  2. 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

  3. Constrained Coding for the Deep-Space Optical Channel

    NASA Astrophysics Data System (ADS)

    Moision, B.; Hamkins, J.

    2002-01-01

    We investigate methods of coding for a channel subject to a large dead-time constraint, i.e., a constraint on the minimum spacing between transmitted pulses, with the deep-space optical channel as the motivating example. Several constrained codes designed to satisfy the dead-time constraint are considered and compared on the basis of throughput, complexity, and decoded error rate. The performance of an iteratively decoded serial concatenation of a constrained code with an outer code is evaluated and shown to provide significant gains over a Reed-Solomon code concatenated with pulse-position modulation.

  4. Constrained coding for the deep-space optical channel

    NASA Astrophysics Data System (ADS)

    Moision, Bruce; Hamkins, Jon

    2002-04-01

    We investigate methods of coding for a channel subject to a large dead-time constraint, i.e., a constraint on the minimum spacing between transmitted pulses, with the deep-space optical channel as the motivating example. Several constrained codes designed to satisfy the dead-time constraint are considered and compared on the basis of throughput, complexity, and decoded error-rate. The performance of an iteratively decoded serial concatenation of a modulation code with an outer code is evaluated and shown to provide significant gains over Reed-Solomon concatenated with Pulse Position Modulation.

  5. Enhancement of upconversion deep-tissue imaging using optical clearing

    NASA Astrophysics Data System (ADS)

    Popov, A. P.; Khaydukov, E. V.; Bykov, A. V.; Semchishen, V. A.; Tuchin, V. V.

    2015-07-01

    We report on the deep-tissue imaging using novel upconversion nanoparticles (UCNPs) β-NaYF4:Yb3+ ,Tm3+ (excitation wavelength: 975 nm, detection wavelength: 800 nm) and glycerol as an optical clearing agent to enhance imaging from under 6-mm-thick porcine muscle tissue samples. We show that improvement of luminescent label visualization is caused by transforming of the diffuse label-emitted light into the direct component. This results in the increase in visibility (ratio of the sum and difference of the maximal and minimal intensity) of the label and increase in maximal signal intensity thus making the combination of the phosphors and optical clearing promising for precise detection of tissue-embedded labelled inhomogeneities.

  6. Exoplanetary Photometry

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph

    2008-09-01

    The Spitzer Space Telescope measured the first photons from exoplanets (Charbonneau et al. 2005, Deming et al. 2005). These secondary eclipses (planet passing behind star) revealed the planet's emitted infrared flux, and under a blackbody assumption provide a brightness temperature in each measured bandpass. Since the initial direct detections, Spitzer has made numerous measurements in the four Infrared Array Camera bandpasses at 3.6, 4.5, 5.7, and 8.0 microns; the Infrared Spectrograph's Blue Peakup Array at 16 microns; and the Multiband Imaging Photometer for Spitzer's 24-micron array. Initial measurements of orbital variation and further photometric study (Harrington et al. 2006, 2007) revealed the extreme day-night variability of some exoplanets, but full orbital phase curves of different planets (Knutson et al. 2007, 2008) demonstrated that not all planets are so variable. This talk will review progress and prospects in exoplanetary photometry.

  7. 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.

  8. ARCHANGEL: Galaxy Photometry System

    NASA Astrophysics Data System (ADS)

    Schombert, James

    2011-07-01

    ARCHANGEL is a Unix-based package for the surface photometry of galaxies. While oriented for large angular size systems (i.e. many pixels), its tools can be applied to any imaging data of any size. The package core contains routines to perform the following critical galaxy photometry functions: sky determinationframe cleaningellipse fittingprofile fittingtotal and isophotal magnitudes The goal of the package is to provide an automated, assembly-line type of reduction system for galaxy photometry of space-based or ground-based imaging data. The procedures outlined in the documentation are flux independent, thus, these routines can be used for non-optical data as well as typical imaging datasets. ARCHANGEL has been tested on several current OS's (RedHat Linux, Ubuntu Linux, Solaris, Mac OS X). A tarball for installation is available at the download page. The main routines are Python and FORTRAN based, therefore, a current installation of Python and a FORTRAN compiler are required. The ARCHANGEL package also contains Python hooks to the PGPLOT package, an XML processor and network tools which automatically link to data archives (i.e. NED, HST, 2MASS, etc) to download images in a non-interactive manner.

  9. New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System

    NASA Astrophysics Data System (ADS)

    Wu, Ya-Lin; Close, Laird M.; Males, Jared R.; Barman, Travis S.; Morzinski, Katie M.; Follette, Katherine B.; Bailey, Vanessa; Rodigas, Timothy J.; Hinz, Philip; 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 YS . With our new photometry and T eff ~ 2500 K derived from the shape of its K-band spectrum, we find that CT Cha B has AV = 3.4 ± 1.1 mag, and a mass of 14-24 MJ 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 × 10-10 M ⊙ yr-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', YS ) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions. This paper includes data gathered with the 6.5 m Magellan Clay Telescope at Las Campanas Observatory, Chile.

  10. Deep-Probe Optical Waveguides for Chemical and Biosensors

    NASA Astrophysics Data System (ADS)

    Zourob, Mohammed; Skivesen, Nina; Horvath, Robert; Mohr, Stephan; Goddard, Nicholas J.

    Typical evanescent wave biosensors generate an electromagnetic wave at the sensor surface that penetrates 100-200 nm into the analysed medium. This has proven to be a highly sensitive tool to monitor refractive index changes in the close vicinity of the sensor surface. The sensitivity of such sensors can be enhanced significantly to monitor interactions caused by large micron scale objects such as bacterial and mammalian cells by increasing the penetration depth of the evanescent field. Recently, different formats of deep-probe optical waveguides including reverse waveguides (RW) based on low refractive index substrates (below 1.33) and metal-clad leaky waveguides (MCLW) have been developed for various sensing applications. These sensors are designed to maximize the overlap between the optical mode and the adlayer (superstrate layer) to be sensed. Increasing the penetration depth of the evanescent field opens up new perspectives for the detection of larger biological objects as it accommodates the majority of their body within the evanescent field. RWs use substrate materials with lower refractive index than that of the monitored superstrate layer (aqueous solution). In MCLWs, a thin metal layer is inserted between the substrate and the thicker waveguide layer. These sensor designs facilitate both increasing and tuning the penetration depth of the modes into the monitored aqueous solution and thereby significantly extend the range of possible application areas of optical waveguide sensors. The developed devices have been used for a range of biosensing applications, including the detection of bacteria, mammalian cells, organophosphorous pesticides and glucose using refractive index changes, absorbance and fluorescence monitoring. Integrating deep-probe sensors with an external electrical field or ultrasonic standing waves shortens analysis time significantly and reduces non-specific binding due to enhanced diffusion of analytes to the immobilized recognition

  11. System requirements for a deep-space optical transceiver

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Chung; Alexander, James W.; Hemmati, Hamid; Monacos, Steve; Yan, Tsun-Yee; Lee, Sukhan; Lesh, James R.; Zingales, Sam

    1999-04-01

    The functional requirements and design drivers for an Optical Communications subsystem are assessed based on the system requirements imposed by a proposed Europa Orbiter mission. Unlike near-Earth optical communications systems, deep space missions impose a unique set of requirements that drives the subsystem design. Significant challenges on laser efficiency, thermal control, pointing and tracking, stray/scatter light control, and subsystem mass/power need to be addressed for a successful subsystem implementation. The baseline design concept for a lasercom subsystem for the Europa orbiter mission employs a 30-cm diameter, diffraction-limited telescope, and a diode pumped solid state laser operating at 1.06 micrometer to support downlink communications. The baseline pointing and tracking approach is to perform Earth Image Tracking with occasional calibration using the Earth- moon or Earth-star images. At high phase angles when the Earth image does not provide sufficient brightness for high rate tracking, inertial sensors (accelerometers) measurements are used to propagate the knowledge of the optical boresight at a higher rate in between celestial reference updates. Additionally, uplink beacon tracking will be used to support pointing at short range and near solar opposition when Earth image alone does not provide sufficient signal power for tracking.

  12. 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.

  13. 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.

  14. 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

  15. Deep-Space Optical Communications Downlink Budget: Modulation and Coding

    NASA Astrophysics Data System (ADS)

    Moision, B.; Hamkins, J.

    2003-08-01

    A link budget for a deep-space optical channel depends in part on the choice of modulation format and error-control coding scheme. This article describes several properties of the channel capacity that lead to an appropriate selection of modulation format, pulse-position modulation (PPM) order, and error-control code rate. It also describes performance limits when additional constraints -- such as bounds on average power, peak power, and uncoded symbol-error rate -- are imposed. We compare these limits to the performance of Reed-Solomon codes and convolutional codes concatenated with PPM, and show that, when iteratively decoded, the concatenated convolutional codes operate approximately 0.5 dB from capacity over a wide range of signal levels, about 2.5 dB better than Reed-Solomon codes.

  16. 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.

  17. Deep CCD Photometry of the Rich Galaxy Cluster Abell 1656: Characteristics of the Dwarf Elliptical Galaxy Population in the Cluster Core

    NASA Astrophysics Data System (ADS)

    Secker, Jeff

    1996-06-01

    I have developed a statistically rigorous and automated program code (DYNAMO) to implement the detection, photometry and classification of faint objects on digital images. Detected objects correspond to local maxima of the intensity distribution, whose peak-flux pixel intensity exceeds a user-defined threshold. For all detected objects, several intensity-weighted quantities are computed: average and centers, the radial moments r_1 and r_-2, the ellipticity epsilon and the concentration index c_in. Then, Kron's 2r_1 total magnitude, integrated colors derived from standard fixed aperture magnitudes, and measures of surface brightness (central and average) are then calculated for each object. The process of discrimination between galaxy and starlike objects is performed interactively, through parameter-space culling and color-magnitude discrimination. Statistical number correction with remote background fields can then be used to further reduce contamination in the resulting distributions. This program code was tested and characterized using artificial CCD images of star and galaxy fields: it is accurate, robust and versatile. I have analyzed deep R- and B-band KPNO 4-m CCD images of the central ~700 arcmin^2 of the Coma cluster (Abell 1656, v ~= 7000 km/s, richness-class 2), using the new photometry software described above. I detected and measured total R magnitudes and (B-R) colors for a sample of 3741 objects in Coma cluster core and 1164 objects on a remote control field, complete to a limiting magnitude of R = 22.5 mag. The typical uncertainties are +-0.06 and +-0.12 mag in total magnitude and color respectively. The dwarf elliptical (dE) galaxies are confined to a tight sequence in the color range given by 0.7 <= (B-R) <= 1.9 mag; within this interval there are 2535 dE candidates in the cluster core, and 694 objects on the control field (2.57 X less area). Scaling the number of objects on the control field to the area of the program fields leaves a sample of

  18. Optical galaxy clusters in the Deep Lens Survey

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Wittman, D.; Dawson, W.

    2014-04-01

    We present the first sample of 882 optically selected galaxy clusters in the Deep Lens Survey (DLS), selected with the Bayesian Cluster Finder. We create mock DLS data to assess completeness and purity rates, and find that both are at least 70 per cent within 0.1 ≤ z ≤ 1.2 for clusters with M200 ≥ 1.2 × 1014 M⊙. We verified the integrity of the sample by performing several comparisons with other optical, weak lensing, X-ray and spectroscopic surveys which overlap the DLS footprint: the estimated redshifts are consistent with the spectroscopic redshifts of known clusters (for z > 0.25 where saturation in the DLS is not an issue); our richness estimates in combination with a previously calibrated richness-mass relation yield individual cluster mass estimates consistent with available Smithsonian Hectospec Lensing Survey dynamical mass estimates; synthetic mass maps made from the optical mass estimates are correlated (>3σ significance) with the weak lensing mass maps; and the mass function thus derived is consistent with theoretical predictions for the cold dark matter scenario. With the verified sample, we investigated correlations between the brightest cluster galaxy (BCG) properties and the host cluster properties within a broader range in redshift (0.25 ≤ z ≤ 0.8) and mass (≥2.4 × 1014 M⊙) than in previous work. We find that the slope of the BCG magnitude-redshift relation throughout this redshift range is consistent with that found at lower redshifts. This result supports an extrapolation to higher redshift of passive evolution of the BCG within the hierarchical scenario.

  19. The XMM Deep Survey in the CDF-S. VII. UV catalogue of the Optical Monitor observations

    NASA Astrophysics Data System (ADS)

    Antonucci, M.; Talavera, A.; Vagnetti, F.; Trevese, D.; Comastri, A.; Paolillo, M.; Ranalli, P.; Vignali, C.

    2015-02-01

    Context. The XMM-Newton X-ray observatory has repeatedly observed the Chandra Deep Field-South (CDF-S) in 33 epochs (2001-2010) through the XMM-CDFS Deep Survey. During the X-ray observations, XMM-OM targeted the central 17 × 17 arcmin2 region of the X-ray field of view, providing simultaneous optical/UV coverage of the CDF-S. The resulting set of data can be used to build an XMM-OM catalogue of the CDF-S, filling the UV spectral coverage between the optical surveys and GALEX observations. Aims: We present the UV catalogue of the XMM-CDFS Deep Survey. Its main purpose is to provide complementary UV average photometric measurements of known optical/UV sources in the CDF-S, taking advantage of the unique characteristics of the survey (UV and X-ray simultaneous data, time monitoring ~8.5 years, multi-wavelength photometry). The data reduction is also intended to improve the standard source detection on individual observations by cataloguing faint sources by stacking their exposure images. Methods: We re-processed the XMM-OM data of the survey and stacked the exposures from consecutive observations using the standard Science Analysis System (SAS) tools to process the data obtained during single observations. Average measurements of detections with SAS good quality flags from individual observations and from stacked images were joined to compile the catalogue. Sources were validated through the cross-identification within the ESO Imaging survey (Arnouts et al. 2001) and the COMBO-17 survey (Wolf et al. 2004). Results: Photometric data of 1129 CDF-S sources are provided in the catalogue, and optical/UV/X-ray photometric and spectroscopic information from other surveys are also included. The stacking extends the detection limits by ~1 mag in the three UV bands, contributing ~30% of the catalogued UV sources. The comparison with the available measurements in similar spectral bands confirms the validity of the XMM-OM calibration. The combined COMBO-17/X-ray classification

  20. Deep Optical Images of Malin 1 Reveal New Features

    NASA Astrophysics Data System (ADS)

    Galaz, Gaspar; Milovic, Carlos; Suc, Vincent; Busta, Luis; Lizana, Guadalupe; Infante, Leopoldo; Royo, Santiago

    2015-12-01

    We present Megacam deep optical images (g and r) of Malin 1 obtained with the 6.5 m Magellan/Clay telescope, detecting structures down to ˜28 B mag arcsec-2. In order to enhance galaxy features buried in the noise, we use a noise reduction filter based on the total generalized variation regularizator. This method allows us to detect and resolve very faint morphological features, including spiral arms, with a high visual contrast. For the first time, we can appreciate an optical image of Malin 1 and its morphology in full view. The images provide unprecedented detail, compared to those obtained in the past with photographic plates and CCD, including Hubble Space Telescope imaging. We detect two peculiar features in the disk/spiral arms. The analysis suggests that the first one is possibly a background galaxy, and the second is an apparent stream without a clear nature, but could be related to the claimed past interaction between Malin 1 and the galaxy SDSSJ123708.91+142253.2. Malin 1 exhibits features suggesting the presence of stellar associations and clumps of molecular gas, not seen before with such a clarity. Using these images, we obtain a diameter for Malin 1 of 160 kpc, ˜50 kpc larger than previous estimates. A simple analysis shows that the observed spiral arms reach very low luminosity and mass surface densities, to levels much lower than the corresponding values for the Milky Way. This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

  1. Implantable micro-optical semiconductor devices for optical theranostics in deep tissue

    NASA Astrophysics Data System (ADS)

    Takehara, Hiroaki; Katsuragi, Yuji; Ohta, Yasumi; Motoyama, Mayumi; Takehara, Hironari; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2016-04-01

    Optical therapy and diagnostics using photoactivatable molecular tools are promising approaches in medical applications; however, a method for the delivery of light deep inside biological tissues remains a challenge. Here, we present a method of illumination and detection of light using implantable micro-optical semiconductor devices. Unlike in conventional transdermal light delivery methods using low-energy light (>620 nm or near-infrared light), in our method, high-energy light (470 nm) can also be used for illumination. Implanted submillimeter-sized light-emitting diodes were found to provide sufficient illumination (0.6-4.1 mW/cm2), and a complementary metal-oxide-semiconductor image sensor enabled the detection of fluorescence signals.

  2. 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.

  3. Optical and Near-Infrared UBVRIJHK Photometry for the RR Lyrae Stars in the Nearby Globular Cluster M4 (NGC 6121)

    NASA Astrophysics Data System (ADS)

    Stetson, P. B.; Braga, V. F.; Dall'Ora, M.; Bono, G.; Buonanno, R.; Ferraro, I.; Iannicola, G.; Marengo, M.; Neeley, J.

    2014-06-01

    We present optical and near-infrared UBVRIJHK photometry of stars in the Galactic globular cluster M4 (NGC 6121) based upon a large corpus of observations obtained mainly from public astronomical archives. We concentrate on the RR Lyrae variable stars in the cluster, and make a particular effort to accurately reidentify the previously discovered variables. We have also discovered two new probable RR Lyrae variables in the M4 field: one of them by its position on the sky and its photometric properties is a probable member of the cluster, and the second is a probable background (bulge?) object. We provide accurate equatorial coordinates for all 47 stars identified as RR Lyraes, new photometric measurements for 46 of them, and new period estimates for 45. We have also derived accurate positions and mean photometry for 34 more stars previously identified as variable stars of other types, and for an additional five non-RR Lyrae variable stars identified for the first time here. We present optical and near-infrared color-magnitude diagrams for the cluster and show the locations of the variable stars in them. We present the Bailey (period-amplitude) diagrams and the period-frequency histogram for the RR Lyrae stars in M4 and compare them to the corresponding diagrams for M5 (NGC 5904). We conclude that the RR Lyrae populations in the two clusters are quite similar in all the relevant properties that we have considered. The mean periods, pulsation-mode ratios, and Bailey diagrams of these two clusters show support for the recently proposed "Oosterhoff-neutral" classification. Based in part on data obtained from the ESO Science Archive Facility under multiple requests by the authors; in part on data obtained from the Isaac Newton Group Archive, which is maintained as part of the CASU Astronomical Data Centre at the Institute of Astronomy, Cambridge; and in part upon data distributed by the NOAO Science Archive. NOAO is operated by the Association of Universities for

  4. 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.

  5. 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.

  6. Periodic Brightness Modulation of the T Tauri Star V716 Per Based on Optical and Infrared Photometry

    NASA Astrophysics Data System (ADS)

    Barsunova, O. Yu.; Grinin, V. P.; Arharov, A. A.; Semenov, A. O.; Sergeev, S. G.; Efimova, N. V.

    2016-06-01

    Results of long-term optical and near infrared observations (VRI and JHK bands, respectively) of the T Tauri star V716 Per are reported. The previously discovered period of the optical brightness variation of the star is confirmed. Our data yield a period of 7.50 days. The period is stable over the entire interval of our observations (about 12 years), although the shape and amplitude of the brightness phase curves varied from season to season. For the first time it is shown that this period is also present in the variations of the JHK infrared fluxes. It is also shown that besides the short period, a slow wave with a duration comparable to the interval of our observations appears in the variations of the star's brightness. Two models of the star's variability are considered for analyzing its photometric behavior: (a) surface activity owing to the existence of cold (magnetic) spots on the star and (b) AA Tau type variability caused by periodic eclipsing of the star by its own circumstellar disk, the inner region of which is warped because of interactions with the star's magnetosphere. The latter model matches the optical observations better. In the infrared, that model only provides a partial fit to the observed variability. In the K band, the major contribution to the variability is from changes in the luminosity of the inner disk caused by fluctuations in the accretion rate.

  7. 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.

  8. Optical/infrared spectroscopy and photometry of the short-period binary RX J1914+24

    NASA Astrophysics Data System (ADS)

    Ramsay, Gavin; Wu, Kinwah; Cropper, Mark; Schmidt, Gary; Sekiguchi, Kazuhiro; Iwamuro, Fumihide; Maihara, Toshinori

    2002-07-01

    We present observations of the proposed double-degenerate polar RX J1914+24. Our optical and infrared spectra show no emission lines. This, coupled with the lack of significant levels of polarization, provides difficulties for a double-degenerate polar interpretation. Although we still regard the double-degenerate polar model as feasible, we have explored alternative scenarios for RX J1914+24. These include a double-degenerate Algol system, a neutron star-white dwarf pair and an electrically powered system. The latter model is particularly attractive since it accounts naturally for the lack of both emission lines and detectable polarization in RX J1914+24. The observed X-ray luminosity is consistent with the predicted power output. If true, then RX J1914+24 would be the first known stellar binary system radiating largely by electrical energy.

  9. FAINT NEAR-ULTRAVIOLET/FAR-ULTRAVIOLET STANDARDS FROM SWIFT/UVOT, GALEX, AND SDSS PHOTOMETRY

    SciTech Connect

    Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter E-mail: hoversten@astro.psu.ed E-mail: brown@astro.psu.ed

    2010-12-10

    At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u {approx} 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (20, 000 < T{sub eff} < 50, 000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.

  10. Absolute Optical Photometry and a Photometric Metallicity Relation for the Nearby Cool Stars from the MEarth Project

    NASA Astrophysics Data System (ADS)

    Dittmann, Jason; Irwin, Jonathan; Charbonneau, David; Newton, Elisabeth R.

    2015-01-01

    There is renewed interest in understanding the low mass stars and brown dwarfs of the solar neighborhood. Since M dwarfs make up the vast majority of stars in the universe, it is essential that we understand their fundamental physical properties. Their ubiquitousness makes them excellent kinematic and chemical probes of the Galaxy, provided we can accurately measure their distances, absolute magnitudes, and metallicities. Additionally, current and future exoplanet surveys that are focused on M dwarfs, such as SPIRou, CARMENES, and the Habitable Zone Planet Finder will uncover a plethora of planetary systems around these stars. Unfortunately, many of the nearby low mass stars are poorly characterized with current data. The MEarth survey has been monitoring approximately 1800 mid-to-late M dwarfs since 2008 and each night also observes a set of Landolt standard stars. We measure a precise optical magnitude in our MEarth bandpass, a red broadband filter similar to the Bessel I filter, for 1500 of these systems. By combining this work with our recent work measuring the trigonometric parallaxes and metallicities of a subset of these M dwarfs, we construct a photometric metallicity relation. We then apply it to the full sample of MEarth-North M dwarfs.The MEarth project gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering, the National Science Foundation under grants AST-0807690, AST-1109468, and AST-1004488, and the John Templeton Foundation.

  11. 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.

  12. 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.

  13. ESO imaging survey. Deep public survey: Multi-color optical data for the Chandra Deep Field South

    NASA Astrophysics Data System (ADS)

    Arnouts, S.; Vandame, B.; Benoist, C.; Groenewegen, M. A. T.; da Costa, L.; Schirmer, M.; Mignani, R. P.; Slijkhuis, R.; Hatziminaoglou, E.; Hook, R.; Madejsky, R.; Rité, C.; Wicenec, A.

    2001-11-01

    This paper presents multi-passband optical data obtained from observations of the Chandra Deep Field South (CDF-S), located at alpha ~ 3h 32m, delta ~ -27o 48'. The observations were conducted at the ESO/MPG 2.2 m telescope at La Silla using the 8kx8k Wide-Field Imager (WFI). This data set, taken over a period of one year, represents the first field to be completed by the ongoing Deep Public Survey (DPS) being carried out as a part of the ESO Imaging Survey (EIS) project. This paper describes the optical observations, the techniques employed for un-supervised pipeline processing and the general characteristics of the final data set. Image processing has been performed using multi-resolution image decomposition techniques adapted to the EIS pipeline. The automatic processing steps include standard de-bias and flat-field, automatic removal of satellite tracks, de-fringing/sky-subtraction, image stacking/mosaicking and astrometry. Stacking of dithered images is carried out using pixel-based astrometry which enables the efficient removal of cosmic rays and image defects, yielding remarkably clean final images. The final astrometric calibration is based on a pre-release of the GSC-II catalog and has an estimated intrinsic accuracy of la 0.10 arcsec, with all passbands sharing the same solution. The paper includes data taken in six different filters (U'UBVRI). The data cover an area of about 0.25 square degrees reaching 5sigma limiting magnitudes of U'AB=26.0, UAB=25.7, BAB=26.4, VAB=25.4, RAB=25.5 and IAB= 24.7 mag, as measured within a 2 x FWHM aperture. The optical data covers an area of ~ 0.1 square degrees for which moderately deep observations in two near-infrared bands are also available, reaching 5sigma limiting magnitudes of JAB ~ 23.4 and KAB ~ 22.6. The current optical/infrared data also fully encompass the region of the deep X-ray observations recently completed by the Chandra telescope. The optical data presented here, as well as the infrared data released

  14. 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

    2016-03-01

    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. PMID:26889570

  15. 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.

  16. Frequency doubling conversion efficiencies for deep space optical communications

    NASA Technical Reports Server (NTRS)

    Robinson, D. L.; Shelton, R. L.

    1987-01-01

    The theory of optical frequency doubling conversion efficiency is analyzed for the small signal input case along with the strong signal depleted input case. Angle phase matching and beam focus spot size are discussed and design trades are described which maximize conversion efficiency. Experimental conversion efficiencies from the literature, which are less than theoretical results at higher input intensities due to saturation, reconversion, and higher order processes, are applied to a case study of an optical communications link from Saturn. Double pass conversion efficiencies as high as 45 percent are expected. It is believed that even higher conversion efficiencies can be obtained using multipass conversion.

  17. 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.

  18. 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)

  19. Optical coupling of deep-subwavelength semiconductor nanowires.

    PubMed

    Cao, Linyou; Fan, Pengyu; Brongersma, Mark L

    2011-04-13

    Systems of coupled resonators manifest a myriad of exciting fundamental physical phenomena. Analogous to the synthesis of molecules from single atoms, the construction of photonic molecules from stand-alone optical resonators represents a powerful strategy to realize novel functionalities. The coupling of high quality factor (Q) dielectric and semiconductor microresonators is by now well-understood and chipscale applications are abound. The coupling behavior of low-Q nanometallic structures has also been exploited to realize high-performance plasmonic devices and metamaterials. Although dense arrays of semiconductor nanoparticles and nanowires (NWs) find increasing use in optoelectronic devices, their photonic coupling has remained largely unexplored. These high refractive index nano-objects can serve as low-Q optical antennas that can effectively receive and broadcast light. We demonstrate that the broad band antenna response of a pair of NWs can be tuned significantly by engineering their optical coupling and develop an intuitive coupled-mode theory to explain our observations. PMID:21443245

  20. Multicolor Optical Photometry of Luminous Novae M31N 2015-09c and M31N 2015-10a

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.; Wolf, M.; Vrastil, J.; Shafter, A. W.; Dabney, D.; DeWitt, R.; Nandho, A.

    2015-10-01

    We report additional multicolor photometry of the luminous novae M31N 2015-09c (PNV J00432114+4124597; see ATel #8108, #8109) and M31N 2015-10a (PNV J00415937+4117026; see CBAT TOCP, ATel #8134, #8141) acquired with the 0.65-m telescope at Ondrejov and Mount Laguna Observatory's 40-inch reflector.

  1. Tailoring Dispersion for Broadband Low-loss Optical Metamaterials Using Deep-subwavelength Inclusions

    PubMed Central

    Jiang, Zhi Hao; Yun, Seokho; Lin, Lan; Bossard, Jeremy A.; Werner, Douglas H.; Mayer, Theresa S.

    2013-01-01

    Metamaterials have the potential to create optical devices with new and diverse functionalities based on novel wave phenomena. Most practical optical systems require that the device properties be tightly controlled over a broad wavelength range. However, optical metamaterials are inherently dispersive, which limits operational bandwidths and leads to high absorption losses. Here, we show that deep-subwavelength inclusions can controllably tailor the dispersive properties of an established metamaterial structure thereby producing a broadband low-loss optical device with a desired response. We experimentally verify this by optimizing an array of nano-notch inclusions, which perturb the mode patterns and strength of the primary and secondary fishnet nanostructure resonances and give an optically thin mid-wave-infrared filter with a broad transmissive pass-band and near-constant group delay. This work outlines a powerful new strategy for realizing a wide range of broadband optical devices that exploit the unique properties of metamaterials. PMID:23535875

  2. Current Applications of Analog Fiber Optics in the NASA/JPL Deep Space Network

    NASA Technical Reports Server (NTRS)

    Lutes, G.

    1993-01-01

    Analog fiber optic technology. Enables a fully integrated Deep Space Communications complex. Enables sharing of expensive subsystems. Enables RF carrier arraying of antennas separated by tens of kilometers. Provides improved complex reliability and flexibility. Enables improved performance. Provides significant cost reductions.

  3. 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.

  4. A plan for the development and demonstration of optical communications for deep space

    NASA Technical Reports Server (NTRS)

    Lesh, James R.; Deutsch, Leslie J.; Weber, William J.

    1991-01-01

    A development history, current status, and prospective development account are given for deep-space optical communications, giving attention to overall systems-related activities and to the generic technology developments required for their implementation. An account is given of the progression envisioned from laboratory subsystems demonstrations to the full-scale flight experiment for the Mars Communications Relay Orbiter missions.

  5. 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.

  6. Optical Characterization of Deep-Space Object Rotation States

    NASA Astrophysics Data System (ADS)

    Hall, D.; Kervin, P.

    2014-09-01

    Analysis of time-series data can yield remarkably accurate estimates of the frequency of a satellites brightness modulations. These apparent or synodic frequencies can vary in time, differing from the actual rotation rate of the object by an amount that depends on the relative angular motion between the satellite, illuminator, and observer for reflected light measurements (or between the satellite and observer for thermal emission measurements). When detected with sufficient accuracy, such synodic frequency variations can be exploited to characterize an objects rotation state, using an analysis that does not require any a priori knowledge of the objects shape. For instance, this shape-independent analysis method can be used to derive spin-axis orientations and sidereal rotation rates for spinning objects. Remotely determining such rotation parameters can be useful in many circumstances, such as when performing anomaly resolution of satellites that have lost stabilization. Unfortunately, synodic variations cannot be detected by ground-based observers for many deep-space objects due to low rates of relative angular motion. This is especially true for objects in geosynchronous orbit. In these cases, deriving spin-axis orientations can be accomplished using a shape-dependent method that employs a model of the shape and reflectance characteristics of the object. Our analysis indicates that a simple cylinder model can often suffice to characterize rotation states for upper-stage rocket bodies.

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

    PubMed

    Kinman, P W; Gagliardi, R M

    1988-11-01

    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. PMID:20539597

  8. Scheme of optical fiber temperature sensor employing deep-grooved process optimization

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Liu, Cong; Xiang, Gaolin; Wang, Ruijie; Wang, Yibing; Xiang, Lei; Wu, Linzhi; Liu, Song

    2015-03-01

    To optimize the optical fiber temperature sensor employing the deep-grooved process, a novel scheme was proposed. Fabricated by the promising CO2 laser irradiation system based on the two-dimensional scanning motorized stage with high precision, the novel deep-grooved optical fiber temperature sensor was obtained with its temperature sensitivity of the transmission attenuation -0.107 dB/°C, which was 18.086 times higher than the optical fiber sensor with the normal depth of grooves while other parameters remained unchanged. The principal research and experimental testing showed that the designed temperature sensor measurement unit had the ability of high sensitivity in transmission attenuation and insensitivity to the wavelength, which offers possible applications in engineering.

  9. 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.

  10. 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. PMID:26556561

  11. 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.

  12. The Multiwavelength Survey by Yale-Chile (MUSYC): Deep Medium-band Optical Imaging and High-quality 32-band Photometric Redshifts in the ECDF-S

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    We present deep optical 18-medium-band photometry from the Subaru telescope over the ~30' × 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 ~40,000 galaxies with R AB < 25.3, the median 5σ limit of the 18 medium bands. Photometric redshifts are determined using the EAzY code and compared to ~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 >~ 3.5. For 0.1 < z < 1.2, we find a 1σ scatter in Δz/(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 ~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. Based (in part) on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  13. 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.

  14. Comparison of the Deep Optic Nerve Head Structure between Normal-Tension Glaucoma and Nonarteritic Anterior Ischemic Optic Neuropathy

    PubMed Central

    Kim, Tae-Woo; Hwang, Jeong-Min

    2016-01-01

    Purpose To compare the deep optic nerve head (ONH) structure between normal-tension glaucoma (NTG) and nonarteritic anterior ischemic optic neuropathy (NAION) and also in healthy subjects as a control using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). Methods This prospective cross-sectional study included 21 NAION patients who had been diagnosed as NAION at least 6 months prior to study entry, and 42 NTG patients and 42 healthy controls who were matched with NAION patients in terms of age, intraocular pressure (IOP), and optic disc area. The retinal nerve fiber layer (RNFL) thickness in the affected sector was also matched between NAION and NTG patients. The ONH was imaged using SD-OCT with the EDI technique. The anterior lamina cribrosa surface depth (LCD) and average prelaminar tissue (PT) thickness were measured in a sector of interest in each eye and compared among the three groups. Results In the sector-matched comparison, LCD was largest in NTG patients, followed by NAION patients, while PT was thinner in NTG patients than in NAION patients (all P < 0.001). NAION patients had a comparable LCD and a thinner PT relative to normal controls (P = 0.170 and < 0.001, respectively). Conclusion The deep ONH configuration is strikingly different between NTG and NAION. The differing features provide comparative insight into the pathophysiology of the two diseases, and may be useful for differential diagnosis. PMID:27035660

  15. 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.

  16. Anatomic and physiologic factors influencing transcutaneous optical diagnosis of deep-seated lesions

    NASA Astrophysics Data System (ADS)

    Thomsen, Sharon L.

    1998-04-01

    Human skin is a formidible light barrier to non-invasive, transcutaneous optical diagnosis of deep-seated lesions. Human skin is composed to two anatomically and physiologically distinct layers, the superficial epidermis and the deeper dermis. Each contains optically active tissue components including scatters, absorber and fluorophores. Beneath the skin is the subcutaneous fibroadipose tissue that varies in thickness and composition depending on the anatomic site and the person's habitus. Delivery of interrogation light and capture of reflected or emitted diagnostic light from deep-seated lesions will be greatly influenced by the skin and subcutaneous tissue. Diagnostic strategies will have to include careful analysis of anatomically distinct 'normal tissues' before 'abnormal lesions' can be distinguished.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. 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.

  19. 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.

  20. 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.

  1. Large Optical Gain AlInN-Delta-GaN Quantum Well for Deep Ultraviolet Emitters

    PubMed Central

    Tan, Chee-Keong; Sun, Wei; Borovac, Damir; Tansu, Nelson

    2016-01-01

    The optical gain and spontaneous emission characteristics of low In-content AlInN-delta-GaN quantum wells (QWs) are analyzed for deep ultraviolet (UV) light emitting diodes (LEDs) and lasers. Our analysis shows a large increase in the dominant transverse electric (TE) polarized spontaneous emission rate and optical gain. The remarkable enhancements in TE-polarized optical gain and spontaneous emission characteristics are attributed to the dominant conduction (C)-heavy hole (HH) transitions achieved by the AlInN-delta-GaN QW structure, which could lead to its potential application as the active region material for high performance deep UV emitters. In addition, our findings show that further optimizations of the delta-GaN layer in the active region are required to realize the high performance AlInN-based LEDs and lasers with the desired emission wavelength. This work illuminates the high potential of the low In-content AlInN-delta-GaN QW structure to achieve large dominant TE-polarized spontaneous emission rates and optical gains for high performance AlN-based UV devices. PMID:26961170

  2. 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.

  3. 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.

  4. Large Optical Gain AlInN-Delta-GaN Quantum Well for Deep Ultraviolet Emitters

    NASA Astrophysics Data System (ADS)

    Tan, Chee-Keong; Sun, Wei; Borovac, Damir; Tansu, Nelson

    2016-03-01

    The optical gain and spontaneous emission characteristics of low In-content AlInN-delta-GaN quantum wells (QWs) are analyzed for deep ultraviolet (UV) light emitting diodes (LEDs) and lasers. Our analysis shows a large increase in the dominant transverse electric (TE) polarized spontaneous emission rate and optical gain. The remarkable enhancements in TE-polarized optical gain and spontaneous emission characteristics are attributed to the dominant conduction (C)-heavy hole (HH) transitions achieved by the AlInN-delta-GaN QW structure, which could lead to its potential application as the active region material for high performance deep UV emitters. In addition, our findings show that further optimizations of the delta-GaN layer in the active region are required to realize the high performance AlInN-based LEDs and lasers with the desired emission wavelength. This work illuminates the high potential of the low In-content AlInN-delta-GaN QW structure to achieve large dominant TE-polarized spontaneous emission rates and optical gains for high performance AlN-based UV devices.

  5. 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.

  6. Detailed optical and near-infrared polarimetry, spectroscopy and broad-band photometry of the afterglow of GRB 091018: polarization evolution

    NASA Astrophysics Data System (ADS)

    Wiersema, K.; Curran, P. A.; Krühler, T.; Melandri, A.; Rol, E.; Starling, R. L. C.; Tanvir, N. R.; van der Horst, A. J.; Covino, S.; Fynbo, J. P. U.; Goldoni, P.; Gorosabel, J.; Hjorth, J.; Klose, S.; Mundell, C. G.; O'Brien, P. T.; Palazzi, E.; Wijers, R. A. M. J.; D'Elia, V.; Evans, P. A.; Filgas, R.; Gomboc, A.; Greiner, J.; Guidorzi, C.; Kaper, L.; Kobayashi, S.; Kouveliotou, C.; Levan, A. J.; Rossi, A.; Rowlinson, A.; Steele, I. A.; de Ugarte Postigo, A.; Vergani, S. D.

    2012-10-01

    Follow-up observations of large numbers of gamma-ray burst (GRB) afterglows, facilitated by the Swift satellite, have produced a large sample of spectral energy distributions and light curves, from which their basic micro- and macro-physical parameters can in principle be derived. However, a number of phenomena have been observed that defy explanation by simple versions of the standard fireball model, leading to a variety of new models. Polarimetry can be a major independent diagnostic of afterglow physics, probing the magnetic field properties and internal structure of the GRB jets. In this paper we present the first high-quality multi-night polarimetric light curve of a Swift GRB afterglow, aimed at providing a well-calibrated data set of a typical afterglow to serve as a benchmark system for modelling afterglow polarization behaviour. In particular, our data set of the afterglow of GRB 091018 (at redshift z = 0.971) comprises optical linear polarimetry (R band, 0.13-2.3 d after burst); circular polarimetry (R band) and near-infrared linear polarimetry (Ks band). We add to that high-quality optical and near-infrared broad-band light curves and spectral energy distributions as well as afterglow spectroscopy. The linear polarization varies between 0 and 3 per cent, with both long and short time-scale variability visible. We find an achromatic break in the afterglow light curve, which corresponds to features in the polarimetric curve. We find that the data can be reproduced by jet break models only if an additional polarized component of unknown nature is present in the polarimetric curve. We probe the ordered magnetic field component in the afterglow through our deep circular polarimetry, finding Pcirc < 0.15 per cent (2σ), the deepest limit yet for a GRB afterglow, suggesting ordered fields are weak, if at all present. Our simultaneous R- and Ks-band polarimetry shows that dust-induced polarization in the host galaxy is likely negligible.

  7. Introductory remarks: Photometry section

    NASA Technical Reports Server (NTRS)

    Ahearn, M. F.

    1981-01-01

    The principal goals of photometry and polarimetry are summarized. These goals include studies of the emission features of gaseous species of comets, the wavelength depenence of albedo, the phase function of scatter distribution, and time variation of rotation. Recent advances in photometric techniques were reviewed and include: use of proper filters, extension to the shortest and longest wavelengths, higher spectral resolving power, and polarizaton techniques.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. 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.

  10. 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.

  11. Single myelin fiber imaging in living rodents without labeling by deep optical coherence microscopy

    NASA Astrophysics Data System (ADS)

    Ben Arous, Juliette; Binding, Jonas; Léger, Jean-François; Casado, Mariano; Topilko, Piotr; Gigan, Sylvain; Claude Boccara, A.; Bourdieu, Laurent

    2011-11-01

    Myelin sheath disruption is responsible for multiple neuropathies in the central and peripheral nervous system. Myelin imaging has thus become an important diagnosis tool. However, in vivo imaging has been limited to either low-resolution techniques unable to resolve individual fibers or to low-penetration imaging of single fibers, which cannot provide quantitative information about large volumes of tissue, as required for diagnostic purposes. Here, we perform myelin imaging without labeling and at micron-scale resolution with >300-μm penetration depth on living rodents. This was achieved with a prototype [termed deep optical coherence microscopy (deep-OCM)] of a high-numerical aperture infrared full-field optical coherence microscope, which includes aberration correction for the compensation of refractive index mismatch and high-frame-rate interferometric measurements. We were able to measure the density of individual myelinated fibers in the rat cortex over a large volume of gray matter. In the peripheral nervous system, deep-OCM allows, after minor surgery, in situ imaging of single myelinated fibers over a large fraction of the sciatic nerve. This allows quantitative comparison of normal and Krox20 mutant mice, in which myelination in the peripheral nervous system is impaired. This opens promising perspectives for myelin chronic imaging in demyelinating diseases and for minimally invasive medical diagnosis.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

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

    PubMed

    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. PMID:26895566

  18. 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.

  19. Selection of modulation and codes for deep-space optical communications

    NASA Astrophysics Data System (ADS)

    Hamkins, Jon; Moision, Bruce

    2004-06-01

    We describe several properties of deep space optical channels that lead to an appropriate selection of modulation format, pulse position modulation (PPM) order, error control code rate, and coding scheme. The selection process is motivated by capacity considerations. We compare the Shannon limit to the performance of Reed-Solomon codes and convolutional codes concatenated with PPM and show that, when iteratively decoded, concatenated convolutional codes operate approximately 0.5 dB from capacity over a wide range of signal levels, about 2.5 dB better than Reed-Solomon codes.

  20. 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.

  1. High-resolution deep-tissue optical imaging using anti-Stokes phosphors

    NASA Astrophysics Data System (ADS)

    Popov, A. P.; Karmenyan, A. V.; Bykov, A. V.; Khaydukov, E. V.; Nechaev, A. V.; Bibikova, O. A.; Panchenko, V. Y.; Semchishen, V. A.; Seminogov, V. N.; Akhmanov, A. S.; Sokolov, V. I.; Kinnunen, M. T.; Tuchin, V. V.; Zvyagin, A. V.

    2013-06-01

    We report on the high-resolution deep-tissue imaging using novel water-dispersible upconversion nanoparticles (UCNPs) β-NaYF4:Yb3+:Tm3+. Luminescence from the UCNP embedded into tissue-mimicking phantoms at the depth of 4 mm epi-illuminated with 975-nm laser radiation was detected. Fiber-optic detection shows 2-times better resolution compared with that obtained using CCD-based imaging modality. The conversion efficiency of upconversion particles and their cytotoxicity to HeLa cells were also investigated and reported.

  2. Blood flow imaging at deep posterior human eye using 1 μm spectral-domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Makita, Shuichi; Fabritius, Tapio; Yasuno, Yoshiaki

    2009-02-01

    Blood flow imaging of deep posterior eye has been demonstrated by using 1-μm spectral-domain optical coherence tomography. The high contrast imaging of deep posterior eye, such as the choroid and the sclera, enables blood flow imaging of choroidal vessels and short posterior ciliary arteries. Optical coherence angiography (OCA) images of outer part from the retinal pigment epithelium (RPE) reveal the vasculature of the choroid and the particular vasculature of short posterior ciliary arteries so-called the circle of Zinn-Haller. To the best of our knowledge, this is the first demonstration for flow imaging the circle of Zinn-Haller with optical coherence tomography.

  3. 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

  4. Deep Optical Imaging of a Compact Group of Galaxies: Seyfert's Sextet

    NASA Astrophysics Data System (ADS)

    Nishiura, Shingo; Murayama, Takashi; Shimada, Masashi; Sato, Yasunori; Nagao, Tohru; Molikawa, Kohji; Taniguchi, Yoshiaki; Sanders, D. B.

    2000-11-01

    To investigate the dynamical status of Seyfert's Sextet (SS), we have obtained a deep optical (VR+I) image of this group. Our image shows that a faint envelope, down to a surface brightness μoptical(AB)~=27 mag arcsec-2, surrounds the member galaxies. This envelope is irregular in shape. It is likely that this shape is attributed either to recent-past or to ongoing galaxy interactions in SS. If the member galaxies have experienced a number of mutual interactions over a long timescale, the shape of the envelope should be rounder. Therefore, the irregularly shaped morphology suggests that SS is in an early phase of dynamical interaction among the member galaxies. It is interesting to note that the soft X-ray image obtained with ROSAT (Pildis, Bregman, & Evrard) is significantly similar in morphology. We discuss the possible future evolution of SS briefly.

  5. 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.

  6. Deep near-infrared adaptive-optics observations of a young embedded cluster at the edge of the RCW 41 H II region

    NASA Astrophysics Data System (ADS)

    Neichel, B.; Samal, M. R.; Plana, H.; Zavagno, A.; Bernard, A.; Fusco, T.

    2015-04-01

    Aims: We investigate the star formation activity in a young star forming cluster embedded at the edge of the RCW 41 H ii region. As a complementary goal, we aim to demonstrate the gain provided by wide-field adaptive optics (WFAO) instruments to study young clusters. Methods: We used deep, JHKs images from the newly commissioned Gemini-GeMS/GSAOI instrument, complemented with Spitzer IRAC observations, in order to study the photometric properties of the young stellar cluster. GeMS is a WFAO instrument that delivers almost diffraction-limited images over a field of ~2' across. The exquisite angular resolution allows us to reach a limiting magnitude of J ~ 22 for 98% completeness. The combination of the IRAC photometry with our JHKs catalog is used to build color-color diagrams, and select young stellar object (YSO) candidates. The JHKs photometry is also used in conjunction with pre-main sequence evolutionary models to infer masses and ages. The K-band luminosity function is derived, and then used to build the initial mass function (IMF) of the cluster. Results: We detect the presence of 80 YSO candidates. Those YSOs are used to infer the cluster age, which is found to be in the range 1 to 5 Myr. More precisely, we find that 1/3 of the YSOs are in a range between 3 to 5 Myr, while 2/3 of the YSO are ≤3 Myr. When looking at the spatial distribution of these two populations, we find evidence of a potential age gradient across the field that suggests sequential star formation. We construct the IMF and show that we can sample the mass distribution well into the brown dwarf regime (down to ~0.01 M⊙). The logarithmic mass function rises to peak at ~0.3 M⊙, before turning over and declining into the brown dwarf regime. The total cluster mass derived is estimated to be 78 ± 18 M⊙, while the ratio derived of brown dwarfs to star is 18 ± 5%. When comparing it with other young clusters, we find that the IMF shape of the young cluster embedded within RCW 41 is

  7. 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

  8. 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.

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

    DOE PAGESBeta

    Caselli, Niccolò; La China, Federico; Bao, Wei; Riboli, Francesco; Gerardino, Annamaria; Li, Lianhe; Linfield, Edmund H.; Pagliano, Francesco; Fiore, Andrea; Schuck, P. James; et al

    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

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

    PubMed

    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

  11. Pulse position modulated (PPM) ground receiver design for optical communications from deep space

    NASA Astrophysics Data System (ADS)

    Biswas, Abhijit; Vilnrotter, Victor; Farr, William H.; Fort, D.; Sigman, E.

    2002-04-01

    Pulse position modulation (PPM) provides a means of using high peak power lasers for transmitting communications signals from planetary spacecraft to earth-based receiving stations. Large aperture (approximately 10 m diameter) telescopes will be used to collect and focus the laser communications signal originating from a deep space transmitter on to a PPM receiver. Large area (1 - 3 mm diameter) sensitive detectors, preceded by appropriate narrow (0.1 - 0.2 nm) optical band-pass filters and followed by low-noise, high-gain, amplifiers will serve as the PPM receiver front end. A digital assembly will form the backbone of the receiver. The PPM receiver will achieve and maintain slot synchronization based on sub slot sums generated by a field programmable-gated array (FPGA). Spacecraft dynamics and timing issues between the ground- based receiver and the transmitter on board the spacecraft must be taken into account. In the present report, requirements and design of a prototype PPM receiver being developed over the next year will be elaborated. The design is driven by the need to demonstrate and validate PPM reception using a variety of detectors under simulated conditions representative of those to be encountered in a deep space optical communications link.

  12. Deep brain optical measurements of cell type–specific neural activity in behaving mice

    PubMed Central

    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 ca2+ 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. PMID:24784819

  13. 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.

  14. Initial Optical Counterpart Identifications for Chandra Deep Survey X-ray Sources towards the Galactic Center

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Grindlay, J. E.; Hong, J.; Laycock, S.; Baganoff, F. K.; Muno, M. P.; Garmire, G. P.; Morris, M.

    2003-03-01

    We present the initial optical counterpart identifications for the Chandra Catalog of X-ray sources towards the Galactic Center (Muno et al. ApJ submitted). 2357 X-ray point sources are detected during 590 ks of Chandra ACIS-I observations with a 17'x17' field around SgrA*. The search for their optical counterparts is conducted with moderately deep V, R, I and Hα images covering the same field taken with the Mosaic camera on the CTIO 4-m telescope in March 2000 as part of the Chandra Multiwavelength Plane (ChaMPlane) Survey. The error radius of each Chandra source is estimated with a raytrace/wavdetect simulation based on the source off-axis angle and net counts. Some 237 sources are detected below 1.2 keV and with >99% source significance in the full 17' field. They are likely sources in the foreground of the Galactic Center. 204 of the 237 sources have matching optical counterparts. For the ˜2000 sources detected in the hard band (2.5--8 keV), only ˜10% have optical matching (at R<23). And most of these ˜10% matches are likely coincident matches with foreground stars. We present our optical counterpart identification method used for the ChaMPlane Survey and the V, R, I, Hα magnitudes of the optical counterparts of this initial sample. This work is supported by NASA/SAO grant AR1-2001X, AR2-3002A and NSF grant AST-0098683.

  15. 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.

  16. Homonymous hemianopia from infarction of the optic tract and lateral geniculate nucleus in deep cerebral venous thrombosis.

    PubMed

    Grabe, Hilary M; Bapuraj, J Rajiv; Wesolowski, Jeffrey R; Parmar, Hemant; Trobe, Jonathan D

    2012-03-01

    A 20-year-old man developed right homonymous hemianopia, hemiparesis, and hemisensory loss from deep cerebral venous thrombosis in the setting of high altitude. Approximately 3 months later, brain MRI showed encephalomalacia of the left optic tract and lateral geniculate nucleus, as well as signal abnormalities of the internal capsule and posterolateral thalamus. Homonymous hemianopia has previously been described in 1 case after deep cerebral venous thrombosis but without detailed neuroimaging features. PMID:22330851

  17. 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

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

    PubMed Central

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

    2016-01-01

    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 1/30th 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. PMID:26925297

  19. Bond-selective imaging of deep tissue through the optical window between 1600 and 1850 nm

    PubMed Central

    Wang, Pu; Wang, Han-Wei; Sturek, Michael; Cheng, Ji-Xin

    2012-01-01

    We report the employment of an optical window between 1600 nm and 1850 nm for bond-selective deep tissue imaging through harmonic vibrational excitation and acoustic detection of resultant pressure waves. In this window where a local minimum of water absorption resides, we found a 5 times enhancement of photoacoustic signal by first overtone excitation of the methylene group CH2 at 1730 nm, compared to the second overtone excitation at 1210 nm. The enhancement allows 3D mapping of intramuscular fat with improved contrast and of lipid deposition inside an atherosclerotic artery wall in the presence of blood. Moreover, lipid and protein are differentiated based on the first overtone absorption profiles of CH2 and methyl group CH3 in this window. VPA imaging of atherosclerotic plaque with the presence of blood. PMID:22125288

  20. 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. PMID:27247104

  1. Breakdown of atomic hyperfine coupling in a deep optical-dipole trap

    NASA Astrophysics Data System (ADS)

    Neuzner, Andreas; Körber, Matthias; Dürr, Stephan; Rempe, Gerhard; Ritter, Stephan

    2015-11-01

    We experimentally study the breakdown of hyperfine coupling for an atom in a deep optical-dipole trap. One-color laser spectroscopy is performed at the resonance lines of a single 87Rb atom for a trap wavelength of 1064 nm. Evidence of hyperfine breakdown comes from three observations, namely, a nonlinear dependence of the transition frequencies on the trap intensity, a splitting of lines which are degenerate for small intensities, and the ability to drive transitions which would be forbidden by selection rules in the absence of hyperfine breakdown. From the data, we infer the hyperfine interval of the 5 P1 /2 state and the scalar and tensor polarizabilities for the 5 P3 /2 state.

  2. 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. PMID:26256148

  3. 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.

  4. Effects of aerosol optical properties on deep convective clouds and radiative forcing

    SciTech Connect

    Fan, Jiwen; Zhang, Renyi; Tao, Wei-Kuo; Mohr, Karen I

    2008-04-23

    The aerosol radiative effects (ARE) on the deep convective clouds are investigated by using a spectral-bin cloud-resolving model coupled with a radiation scheme and an explicit land surface model. The sensitivity of cloud properties and the associated radiative forcing to aerosol single-scattering albedo (SSA) are examined. The ARE on cloud properties is pronounced for mid-visible SSA of 0.85. Relative to the case without ARE, the cloud fraction and optical depth decrease by about 18% and 20%, respectively. Ice particle number concentrations, liquid water path, ice water path, and droplet size decrease by more than 15% when the ARE is introduced. The ARE causes a surface cooling of about 0.35 K and significantly high heating rates in the lower troposphere (about 0.6 K day-1 higher at 2 km), both of which lead to a more stable atmosphere and hence weaker convection. The weaker convection explains the less cloudiness, lower cloud optical depth, less LWP and IWP, smaller droplet size, and less precipitation resulting from the ARE. The daytime-mean direct forcing induced by black carbon is about 2.2 W m-2 at the top of atmosphere (TOA) and -17.4 W m-2 at the surface for SSA of 0.85. The semi-direct forcing is positive, about 10 and 11.2 W m-2 at the TOA and surface, respectively. Both the TOA and surface total radiative forcing values are strongly negative for the deep convective clouds, attributed mostly to aerosol indirect forcing. Aerosol direct and semi-direct effects are very sensitive to SSA when aerosol optical depth is high. Because the positive semi-direct forcing compensates the negative direct forcing at the surface, the surface temperature and heat fluxes decrease less significantly with the increase of aerosol absorption (decreasing SSA). The cloud fraction, optical depth, convective strength, and precipitation decrease with the increase of absorption, resulting from a more stable atmosphere due to enhanced

  5. Effects of aerosol optical properties on deep convective clouds and radiative forcing

    NASA Astrophysics Data System (ADS)

    Fan, Jiwen; Zhang, Renyi; Tao, Wei-Kuo; Mohr, Karen I.

    2008-04-01

    The aerosol radiative effects (ARE) on the deep convective clouds are investigated by using a spectral-bin cloud-resolving model coupled with a radiation scheme and an explicit land surface model. The sensitivity of cloud properties and the associated radiative forcing to aerosol single-scattering albedo (SSA) are examined. The ARE on cloud properties is pronounced for mid-visible SSA of 0.85. Relative to the case without ARE, the cloud fraction and optical depth decrease by about 18% and 20%, respectively. Ice particle number concentrations, liquid water path, ice water path, and droplet size decrease by more than 15% when the ARE is introduced. The ARE causes a surface cooling of about 0.35 K and significantly high heating rates in the lower troposphere (about 0.6 K day-1 higher at 2 km), both of which lead to a more stable atmosphere and hence weaker convection. The weaker convection explains the less cloudiness, lower cloud optical depth, less LWP and IWP, smaller droplet size, and less precipitation resulting from the ARE. The daytime-mean direct forcing induced by black carbon is about 2.2 W m-2 at the top of atmosphere (TOA) and -17.4 W m-2 at the surface for SSA of 0.85. The semi-direct forcing is positive, about 10 and 11.2 W m-2 at the TOA and surface, respectively. Both the TOA and surface total radiative forcing values are strongly negative for the deep convective clouds, attributed mostly to aerosol indirect forcing. Aerosol direct and semi-direct effects are very sensitive to SSA when aerosol optical depth is high. Because the positive semi-direct forcing compensates the negative direct forcing at the surface, the surface temperature and heat fluxes decrease less significantly with the increase of aerosol absorption (decreasing SSA). The cloud fraction, optical depth, convective strength, and precipitation decrease with the increase of absorption, resulting from a more stable atmosphere due to enhanced surface cooling and atmospheric heating.

  6. 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).

  7. Sudden-quench dynamics of Bardeen-Cooper-Schrieffer states in deep optical lattices

    NASA Astrophysics Data System (ADS)

    Nuske, Marlon; Mathey, L.; Tiesinga, Eite

    2016-08-01

    We determine the exact dynamics of an initial Bardeen-Cooper-Schrieffer (BCS) state of ultracold atoms in a deep hexagonal optical lattice. The dynamical evolution is triggered by a quench of the lattice potential such that the interaction strength Uf is much larger than the hopping amplitude Jf. The quench initiates collective oscillations with frequency | Uf|/2 π in the momentum occupation numbers and imprints an oscillating phase with the same frequency on the BCS order parameter Δ . The oscillation frequency of Δ is not reproduced by treating the time evolution in mean-field theory. In our theory, the momentum noise (i.e., density-density) correlation functions oscillate at frequency | Uf|/2 π as well as at its second harmonic. For a very deep lattice, with zero tunneling energy, the oscillations of momentum occupation numbers are undamped. Nonzero tunneling after the quench leads to dephasing of the different momentum modes and a subsequent damping of the oscillations. The damping occurs even for a finite-temperature initial BCS state, but not for a noninteracting Fermi gas. Furthermore, damping is stronger for larger order parameter and may therefore be used as a signature of the BCS state. Finally, our theory shows that the noise correlation functions in a honeycomb lattice will develop strong anticorrelations near the Dirac point.

  8. Acceptor levels in ZnMgO:N probed by deep level optical spectroscopy

    SciTech Connect

    Kurtz, A.; Hierro, A. Muñoz, E.

    2014-02-24

    A combination of deep level optical spectroscopy and lighted capacitance voltage profiling has been used to analyze the effect of N into the energy levels close to the valence band of Zn{sub 0.9}Mg{sub 0.1}O. Three energy levels at E{sub V} + 0.47 eV, E{sub V} + 0.35 eV, and E{sub V} + 0.16 eV are observed in all films with concentrations in the range of 10{sup 15}–10{sup 18} cm{sup −3}. The two shallowest traps at E{sub V} + 0.35 eV and E{sub V} + 0.16 eV have very large concentrations that scale with the N exposure and are thus potential acceptor levels. In order to correctly quantify the deep level concentrations, a metal-insulator-semiconductor model has been invoked, explaining well the resulting capacitance-voltage curves.

  9. Characterizing deep optical-sectioning microscopy performance with scattering phantoms and numerical simulations

    NASA Astrophysics Data System (ADS)

    Liu, Jonathan T. C.; Mandella, Michael J.; Kino, Gordon S.; Contag, Christopher H.

    2010-02-01

    Microscopes are being developed for use in living animals, and even humans, to image microanatomical changes and molecular markers that are associated with disease. Phantoms that can be used to evaluate the performance characteristics of these systems have not been well described or standardized. We have been developing the tools to evaluate a dual-axis confocal (DAC) microscope design to optimize the features required for in vivo diagnosic imaging, and these may have features that are useful for evaluation of other such devices. We have performed diffraction-theory modeling, Monte-Carlo scattering simulations, reflectance experiments in tissue phantoms, and tissue-imaging validations. First, we determined how scattering from tissue deteriorates the diffraction-limited transverse and vertical responses in reflectance DAC imaging. Specifically, the vertical and transverse responses of the DAC to a plane reflector and a knife edge, respectively, were measured at various depths in an Intralipid scattering phantom. Comparisons were made with both diffraction-theory and Monte-Carlo scattering simulations. Secondly, as a practical demonstration of deep-tissue fluorescence microscopy, three-dimensional fluorescence images were obtained in thick human biopsy samples. These results demonstrate that the efficient rejection of scattered light in a DAC microscope enables deep optical sectioning in tissue. Finally, we will discuss our needs and plans for similar tissue-phantom experiments to validate the performance of multimodal optical- and ultrasound-imaging platforms under development. As devices are developed for the imaging of epithelial surfaces and substructures, standardized phantoms that represent the multilayered anatomical features of these tissues will need to be developed.

  10. 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.

  11. Improved Constraints on Type Ia Supernova Host Galaxy Properties using Multi-Wavelength Photometry and their Correlations with Supernova Properties

    SciTech Connect

    Gupta, Ravi R.; D'Andrea, Chris B.; Sako, Masao; Conroy, Charlie; Smith, Mathew; Bassett, Bruce; Frieman, Joshua A.; Garnavich, Peter M.; Jha, Saurabh W.; Kessler, Richard; Lampeitl, Hubert; /Portsmouth U., ICG /Fermilab

    2011-07-01

    We improve estimates of the stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year Sloan Digital Sky Survey (SDSS-II) Supernova Survey (median redshift of z {approx} 0.2) and multi-wavelength host-galaxy photometry from SDSS, the Galaxy Evolution Explorer, and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we present evidence of a correlation (1.9{sigma} confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0{sigma} level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.

  12. Photometry and the Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Rodrigo, C.; Solano, E.

    2013-05-01

    Building Spectral Energy Distributions combining data from different sources is becoming more important as astronomy takes an increasingly multi-wavelength approach. In order to do this, photometry data must be described in sufficient detail to allow for the conversion to compatible flux density units (including the description of magnitude systems and zero points). Furthermore, comparing observed photometry with the synthetic one for theoretical models allows to infer physical properties from the observed objects. But in order to do that, an even more detailed description of the observed photometric points is needed, including the transmission curves of the filters corresponding to the observed data. In the Virtual Observatory an important effort has been done towards this standardization with the Photometry Data Model. And in the SVO we have developed several services to help in this direction, providing detailed information about filters, synthetic photometry for theoretical models and tools to use all this to analyze observed data and estimate object physical properties.

  13. Options for daytime monitoring of atmospheric visibility in optical communications

    NASA Technical Reports Server (NTRS)

    Erickson, D.; Cowles, K.

    1989-01-01

    Techniques for daytime detection of atmospheric transmission and cloud cover to determine the capabilities of future deep-space optical communications links are considered. A modification of the planned nighttime photometry program will provide the best data while minimizing the need for further equipment. Greater degrees of modification will provide increased detection capabilities. Future testing of the equipment will better define the improvement offered by each level of modification. Daytime photometry is favored at certain wavelengths because of higher transmission and lower background noise, thus giving an increased signal-to-noise ratio. A literature search has provided a list of stars brighter than second magnitude at these wavelengths.

  14. The results of X-ray binary Cyg X-1 investigations based on the optical photometry and high-resolution spectroscopy

    NASA Astrophysics Data System (ADS)

    Karitskaya, Eugenia A.

    2007-04-01

    Selected results of multi-year optical photometric and high-resolution spectral observations including obtained in the frame of coordinated CIS countries campaign "Optical Monitoring of Unique Astrophysical Objects" are briefly reviewed. Comparison with ASM/RXTE X-ray data is used. Besides of orbital variations different kinds of flares, dips and so-called precession period 147/294 days were revealed. The observational evidences of instability of matter flowing from one component to another have been appeared. Cross-correlation analysis yielded the lags between the optical and X-ray (2-10 keV) long time variations with the delaying of the last ones on 7d in 1996 and 12d in 1997-1998. The very same lags were revealed between the optical and X-ray flares in these years. So the characteristic time of the matter transfer through the accretion disk was about 7 days in Summer and Autumn 1996 and about 12 days in 1997-1998 and alpha-model of accretion disc does not work. Optical spectral line profile variations were found during X-ray flare. The comparison of observed and non-LTE model profiles for HI, HeI and MgII is given taking into account tidal distortion of Cyg X-1 optical component and its illumination by X-ray emission of secondary one. We set limits on the optical component main characteristics T[eff] = 30400±500K, log g = 3.31±0.07 and overabundance of He and Mg: [He/H] = 0.43±0.06 dex, [Mg/H] = 0.75±0.15 dex by using spectra of 2003-2004. The Doppler images were reconstructed by an improved Doppler tomography method on the base of 9 HeIIλ4686Å profiles of 2003 ("soft" X-ray state) and 6 profiles of 2004 ("hard" X-ray state). It allowed putting a limitation on the black hole to supergiant mass ratio 1/4 ≤ M[X]/M[O] ≤ 1/3. The photometric and spectral variations point to the supergiant parameters changes on the time scale of tens of years. Line profile non-LTE simulations lead to the conclusion that the star radius has grown about 1-4% from 1997 to 2003

  15. Optimising deep anterior lamellar keratoplasty (DALK) using intraoperative online optical coherence tomography (iOCT)

    PubMed Central

    Steven, Philipp; Le Blanc, Carolin; Lankenau, Eva; Krug, Marc; Oelckers, Stefan; Heindl, Ludwig M; Gehlsen, Uta; Huettmann, Gereon; Cursiefen, Claus

    2014-01-01

    Background/aims To describe the use of intraoperative online optical coherence tomography (iOCT) for improving deep anterior lamellar keratoplasty (DALK) surgery. Methods Retrospective case series of 6 eyes of 6 male patients with keratokonus, corneal dystrophy or herpetic stromal scars undergoing DALK were investigated using intraoperative optical coherence tomography and postsurgical image/video analysis. Main outcome measures were: visibility of surgical steps, especially, assessment of placement depth of injection needle, preparation of bare Descemet's membrane and drainage of interface fluid. Results iOCT enables real-time visualisation of all surgical steps of DALK procedure in all patients. Placement of air injection needle above Descemet's membrane was reliably monitored as was presence of bare Descemet's membrane and potential interface fluid. Conclusions iOCT assists with visualisation of injection needle placement and with assessment of bare Descemet's membrane as well as interface fluid during the DALK procedure. Overall iOCT may be a helpful device that supports surgeons in all steps of DALK procedure. PMID:24590554

  16. Asteroid Lightcurve Photometry

    NASA Astrophysics Data System (ADS)

    Harris, A. W.

    2004-05-01

    With the advent of modestly priced CCD cameras and computer controller and reduction software, amateurs can now do photometry on fainter targets than was possible even from large observatories only a decade or so ago. This has led to an explosion of lightcurve data that in turn has yielded rich results. We now have rotation periods for more than 1500 asteroids, extending down to objects only tens of meters in diameter, and well determined shapes and pole orientations of more than 100 objects. Among smaller asteroids, the dispersion in rotation rates ranges from minutes to months, with the slower ones mostly "tumbling," or in states of non-principal axis rotation. The fastest ones must be monolithic, as centrifugal force exceeds their gravity. But among those larger than a few hundred meters diameter, there is a "rotation barrier" at the rate where gravity and centrifugal force match, suggesting that most asteroids this large or larger are "rubble piles." The broad dispersion in spin rates, almost a bimodal distribution, has long been a mystery, but now appears likely to be due to thermal radiation torques from the randomly asymmetric shapes of small asteroids. This is a major paradigm shift from the past, where mutual collisions were considered to be the dominant (or only) evolutionary process affecting spins. Amateur observations have already contributed a great deal leading to this new view, and much remains to be done, providing abundant opportunities for amateur-professional collaborations.

  17. Photometry from space

    NASA Technical Reports Server (NTRS)

    Nelson, M. J.; Bless, R. C.; Percival, J. W.; White, R. L.

    1992-01-01

    A brief description of the High Speed Photometer (HSP) of the Hubble Space Telescope is given, in particular the HSP light path, detectors, entrance apertures, and filters. The status of HSP testing to date is reported, and problems encountered with the bright earth and the telescope pointing system are described. The calibration effort for the HSP is well under way. Results of internal (instrument coordinate) aperture locations good to 0.05 arcsec and external (telescope coordinate) locations good to 0.02 arcsec are shown. The effects of spacecraft pointing and jitter on HSP photometry are detailed, and a preliminary measurement of spacecraft jitter with HSP is shown. The aperture calibration effort is verified by accurate pointing of a star to different HSP 1.0 arcsec entrance apertures, and photometric performance of the instrument is shown to be accurate to the 2 percent photon noise of the observations. Future science verification and guaranteed observing time programs are listed. Suggestions are made for future space-based photometers.

  18. 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

  19. The Chandra Deep Field North Survey. XV. Optically Bright, X-Ray-Faint Sources

    NASA Astrophysics Data System (ADS)

    Hornschemeier, A. E.; Bauer, F. E.; Alexander, D. M.; Brandt, W. N.; Sargent, W. L. W.; Bautz, M. W.; Conselice, C.; Garmire, G. P.; Schneider, D. P.; Wilson, G.

    2003-08-01

    We have analyzed optically bright, X-ray-faint [OBXF; i.e., log(fX/fR)<~-2] sources identified in an 178.9 arcmin2 area having high exposure (greater than 1500 ks) within the Chandra Deep Field North 2 Ms survey. We find 43 OBXF sources in this area, making up ~15% of the X-ray sources above a 0.5-2 keV flux of ~2.3×10-17 ergs cm-2 s-1. We present spectroscopic identifications for 42 of the OBXF sources and optical spectra for 25, including five previously unpublished redshifts. Deep optical imaging data (either Hubble Space Telescope [HST] or ground-based) are presented for all the OBXF sources; we measure the optical morphologies of the 20 galaxies having HST imaging data. The OBXF population consists mainly of normal and starburst galaxies detected out to cosmologically significant distances (i.e., to a median redshift of z=0.297 and a full redshift range z=0.06-0.845). This is notable since these distances equate to look-back times of up to ~8 Gyr; we are thus provided with a window on the X-ray emission from galaxies at redshifts much closer to the cosmic star formation peak than was possible prior to the Chandra X-Ray Observatory. The X-ray luminosity distribution of OBXF sources extends to higher luminosity than does that of ``normal'' galaxies, indicating that a significant fraction are likely dominated by low-luminosity active galactic nuclei or vigorous star formation. The lowest redshift galaxies (z~0.06-0.2) have very low X-ray-to-optical flux ratios [i.e., log(fX/fR)<~-3], which are consistent with those of normal galaxies in the local universe. By combining the detected X-ray counts, we find the average OBXF X-ray spectrum to be consistent with a Γ~2.0 power law. The 0.5-2 keV logN-logS for the OBXF galaxies is much steeper (α~-1.7) than for the general X-ray source population. Indeed, the number of OBXF sources has doubled between the 1 and 2 Ms surveys, rising sharply in numbers at faint fluxes. The extragalactic OBXF sources are found to

  20. 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.

  1. 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.

  2. Radio Timing and Optical Photometry of the Black Widow System PSR J1953+1846A in the Globular Cluster M71

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    We report on the determination of the astrometric, spin, and orbital parameters for PSR J1953+1846 A, a “black widow” binary millisecond pulsar in the globular cluster M71. By using the accurate position and orbital parameters obtained from radio timing, we identified the optical companion in Advanced Camera for Surveys/Hubble Space Telescope images. It turns out to be a faint ({m}{{F}606{{W}}}≳ 24, {m}{{F}814{{W}}}≳ 23) and variable star located at only ˜0.″06 from the pulsar timing position. The light curve shows a maximum at the pulsar inferior conjunction and a minimum at the pulsar superior conjunction, thus confirming the association with the system. The shape of the optical modulation suggests that the companion star is heated, likely by the pulsar wind. The comparison with the X-ray light curve possibly suggests the presence of an intra-binary shock due to the interaction between the pulsar wind and the material released by the companion. This is the second identification (after COM-M5C) of an optical companion to a black widow pulsar in a globular cluster. Interestingly, the two companions show a similar light curve and share the same position in the color-magnitude diagram. Based on observations collected with the NASA/ESA HST (Prop. 12932), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.

  3. Subaru Super Deep Field with Adaptive Optics. I. Observations and First Implications

    NASA Astrophysics Data System (ADS)

    Minowa, Yosuke; Kobayashi, Naoto; Yoshii, Yuzuru; Totani, Tomonori; Maihara, Toshinori; Iwamuro, Fumihide; Takami, Hideki; Takato, Naruhisa; Hayano, Yutaka; Terada, Hiroshi; Oya, Shin; Iye, Masanori; Tokunaga, Alan T.

    2005-08-01

    We present a deep K'-band (2.12 μm) imaging of the 1'×1' Subaru Super Deep Field (SSDF) taken with the Subaru adaptive optics (AO) system. Total integration time of 26.8 hr results in the limiting magnitude of K'~24.7 (5 σ, 0.2" aperture) for point sources and K'~23.5 (5 σ, 0.6" aperture) for galaxies, which is the deepest limit ever achieved in the K' band. The average stellar full width at half-maximum (FWHM) of the co-added image is 0.18". Based on the photometric measurements of detected galaxies, we obtained the differential galaxy number counts, for the first time, down to K'~25, which is more than 0.5 mag deeper than the previous data. We found that the number count slope dlogN/dm is about 0.15 at 22

  4. 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.

  5. 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.

  6. 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.

  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. Deep optical survey of the stellar content of Sh2-311 region

    NASA Astrophysics Data System (ADS)

    Yadav, Ram Kesh; Pandey, A. K.; Sharma, Saurabh; Jose, J.; Ogura, K.; Kobayashi, N.; Samal, M. R.; Eswaraiah, C.; Chandola, H. C.

    2015-01-01

    The stellar content in and around Sh2-311 region have been studied using the deep optical observations as well as near-infrared (NIR) data from 2MASS. The region contains three clusters, viz. NGC 2467, Haffner 18 and Haffner 19. We have made an attempt to distinguish the stellar content of these individual regions as well as to re-determine their fundamental parameters such as distance, reddening, age, onto the basis of a new and more extended optical and infrared photometric data set. NGC 2467 and Haffner 19 are found to be located in the Perseus arm at the distances of 5.0 ± 0.4 kpc and 5.7 ± 0.4 kpc, respectively, whereas Haffner 18 is located at the distance of 11.2 ± 1.0 kpc. The clusters NGC 2467 and Haffner 19 might have formed from the same molecular cloud, whereas the cluster Haffner 18 is located in the outer galactic arm, i.e. the Norma-Cygnus arm. We identify 8 class II young stellar objects (YSOs) using the NIR (J-H)/(H-K) two colour diagram. We have estimated the age and mass of the YSOs identified in the present work and those by Snider et al. (2009) using the V/(V-I) colour-magnitude diagram. The estimated ages and mass range of the majority of the YSOs are ≲1 Myr and ∼0.4-3.5 M⊙, respectively, indicating that these sources could be T-Tauri stars or their siblings. Spatial distribution of the YSOs shows that some of the YSOs are distributed around the HII region Sh2-311, suggesting a triggered star formation at its periphery.

  9. 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.

  10. Designing a deep-ultraviolet nonlinear optical material with a large second harmonic generation response.

    PubMed

    Wu, Hongping; Yu, Hongwei; Yang, Zhihua; Hou, Xueling; Su, Xin; Pan, Shilie; Poeppelmeier, Kenneth R; Rondinelli, James M

    2013-03-20

    The generation of intense coherent deep-UV light from nonlinear optical materials is crucial to applications ranging from semiconductor photolithography and laser micromachining to photochemical synthesis. However, few materials with large second harmonic generation (SHG) and a short UV-cutoff edge are effective down to 200 nm. A notable exception is KBe2BO3F2, which is obtained from a solid-state reaction of highly toxic beryllium oxide powders. We designed and synthesized a benign polar material, Ba4B11O20F, that satisfies these requirements and exhibits the largest SHG response in known borates containing neither lone-pair-active anions nor second-order Jahn-Teller-active transition metals. We developed a microscopic model to explain the enhancement, which is unexpected on the basis of conventional anionic group theory arguments. Crystal engineering of atomic displacements along the polar axis, which are difficult to attribute to or identify within unique anionic moieties, and greater cation polarizabilities are critical to the design of next-generation SHG materials. PMID:23448539

  11. Deep Optical Spectroscopy of Planetary Nebulae: The Search for Neutron-Capture Elements

    NASA Astrophysics Data System (ADS)

    Sterling, Nicholas C.; Garofali, K.; Dinerstein, H. L.; Hwang, S.; Redfield, S.

    2013-01-01

    We present deep, high-resolution (R=36,700) optical spectra of five planetary nebulae (PNe), taken with the 2D-coude echelle spectrograph on the 2.7-m Harlan J. Smith Telescope at McDonald Observatory. These observations are part of a larger optical survey of PNe, designed to unambiguously detect emission lines from neutron(n)-capture elements (atomic number Z>30). The abundances of these elements are of particular interest in PNe, since they can be produced by slow n-capture nucleosynthesis (the ``s-process'') during the asymptotic giant branch (AGB) stage of evolution of PN progenitor stars. The first large-scale investigation of n-capture element abundances in PNe (Sterling & Dinerstein 2008, ApJS, 174, 157) surveyed [Kr III] and [Se IV] transitions in the K band spectra of more than 80 PNe. However, the abundances derived from these data relied on ionization corrections that were often large and uncertain due to the detection of only one ion per element. Transitions of other Se and Kr ions, as well as many other trans-iron species, reside at optical wavelengths. High-resolution spectra are essential to unequivocally identify these lines and resolve potential blends with other species. The spectra we present are rich in emission features, with between 125 and 600 distinct lines detected in each PN. Emission from at least one Kr ion is detected in all five objects, and two (Hb 12 and J 900) exhibit emission from multiple Kr ions. We detected multiple Xe ions in J 900, as well as Se, Br, and Rb lines. Hb 12 also exhibits Xe emission, and the first detection of [Se II] in a PN to our knowledge. The spectra display a wealth of other emission lines, including permitted features of second-row elements and forbidden transitions of several iron-peak elements (e.g., Cr, Mn, Fe, Co, Ni, and Cu). Our survey makes it possible to derive more accurate Se and Kr abundances in PNe, and reveals the enrichment of other trans-iron elements. This enables more accurate s

  12. Validation of Fiber-Optic Strain-Sensing Cable for Deep Underground Application

    NASA Astrophysics Data System (ADS)

    Noni, N.; Filler, L.; Maclaughlin, M.; Wang, H. F.

    2010-12-01

    The laboratory tests presented here are in preparation for rock deformation monitoring at the Deep Underground Science and Engineering Laboratory (DUSEL). These tests validate the strain-sensing capability of fiber optic cable. In contrast to traditional, point-measurement sensors, this Distributed Strain and Temperature (DST) cable provides continuous data along its length, up to several kilometers. The fiber optic cable was subjected to increasing tensile strain in two different test setups. The first setup checked for slip between the glass fiber and the outer layers of the cable. The second setup proved that the experiment design is adequate for comparing recorded strain with analytical strain. The first test setup held a 3.5-meter cable between two clamps with screws that allowed fine increases in cable length. These changes in length were measured with a digital caliper and were used to calculate incremental strain values. The data sets for caliper-measured strain and recorded strain plotted as parallel straight lines, indicating no slip between the fiber and the cable’s outer layers. Our lines also matched the manufacturer’s slope and intercept within 10%. The second test setup approximated an ideally deflected beam. The concrete beam had a 3-meter cable resting on top, attached at each end. An analytical solution provided strain values as a function of beam thickness and radius of curvature. The beam was incrementally bent by placing it on supporting arches of increasing center height. The arches were cut to various radii for center deflections of 0 - 5 inches. For each radius, there was a reasonable comparison between the recorded strain and analytical strain. Ongoing understanding and application of the DST system may improve that comparison. The ultimate goal is to develop a robust and practical attachment method that does not allow slip between the cable and the rock. Continuing lab work will test various methods of attaching the entire cable length

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  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. 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.

  6. TFIT: A Photometry Package for Mixed-Resolution Datasets

    NASA Astrophysics Data System (ADS)

    Laidler, V. G.; Grogin, N.; Clubb, K.; Ferguson, H.; Papovich, C.; Dickinson, M.; Idzi, R.; MacDonald, E.; Ouchi, M.; Mobasher, B.

    2006-07-01

    TFIT is a software package for measuring relative galaxy photometry between imaging data sets with different angular resolutions, such as the Hubble ACS and Spitzer IRAC images taken for the Great Observatories Origins Deep Survey (GOODS). It combines prior information about spatial position and morphology obtained from high angular resolution images with PSF information about both images to construct object templates, which it then fits to a lower-resolution image of the same field. Simulations demonstrate that this technique improves accuracy in uncrowded fields, with performance holding steady as crowding increases and object separation decreases to 1.5 PSF FWHM: outperforming SExtractor by a factor of two. Photometry is also measured, with < 10% degradation, for objects that SExtractor fails to deblend. On real GOODS data, TFIT produces results that are consistent with a traditional PSF subtraction method. TFIT is implemented in Python and C++.

  7. A Comprehensive Study of Detectability and Contamination in Deep Rapid Optical Searches for Gravitational Wave Counterparts

    NASA Astrophysics Data System (ADS)

    Cowperthwaite, P. S.; Berger, E.

    2015-11-01

    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 deg2. 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 (trise ≲ 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 telescope and Hyper

  8. Simulations of deep galaxy fields. 1: Monte Carlo simulations of optical and near-infrared counts

    NASA Technical Reports Server (NTRS)

    Chokshi, Arati; Lonsdale, Carol J.; Mazzei, Paola; De Zotti, Gianfranco

    1994-01-01

    Monte Carlo simulations of three-dimensional galaxy distributions are performed, following the 1988 prescription of Chokshi & Wright, to study the photometric properties of evolving galaxy populations in the optical and near-infrared bands to high redshifts. In this paper, the first of a series, we present our baseline model in which galaxy numbers are conserved, and in which no explicit 'starburst' population is included. We use the model in an attempt to simultaneously fit published blue and near-infrared photometric and spectroscopic observations of deep fields. We find that our baseline models, with a formation redshift, z(sub f), of 1000, and H(sub 0) = 50, are able to reproduce the blue counts to b(sub j) = 22, independent of the value of Omega(sub 0), and also to provide a satisfactory fit to the observed blue-band redshift distributions, but for no value of Omega(sub 0) do we achieve an acceptable fit to the fainter blue counts. In the K band, we fit the number counts to the limit of the present-day surveys only for an Omega(sub 0) = 0 cosmology. We investigate the effect on the model fits of varying the cosmological parameters H(sub 0), the formation red-shift z(sub f), and the local luminosity function. Changing H(sub 0) does not improve the fits to the observations. However, reducing the epoch of a galaxy formation used in our simulations has a substantial effect. In particular, a model with z(sub f) approximately equal to 5 in a low Omega(sub 0) universe improves the fit to the faintest photometric blue data without any need to invoke a new population of galaxies, substantial merging, or a significant starburst galaxy population. For an Omega(sub 0) = 1 universe, however, reducing z(sub f) is less successful at fitting the blue-band counts and has little effect at all at K. Varying the parameters of the local luminosity function can also have a significant effect. In particular the steep low end slope of the local luminosity function of Franceschini et

  9. Improving satellite quantitative precipitation estimates by incorporating deep convective cloud optical depth

    NASA Astrophysics Data System (ADS)

    Stenz, Ronald D.

    As Deep Convective Systems (DCSs) are responsible for most severe weather events, increased understanding of these systems along with more accurate satellite precipitation estimates will improve NWS (National Weather Service) warnings and monitoring of hazardous weather conditions. A DCS can be classified into convective core (CC) regions (heavy rain), stratiform (SR) regions (moderate-light rain), and anvil (AC) regions (no rain). These regions share similar infrared (IR) brightness temperatures (BT), which can create large errors for many existing rain detection algorithms. This study assesses the performance of the National Mosaic and Multi-sensor Quantitative Precipitation Estimation System (NMQ) Q2, and a simplified version of the GOES-R Rainfall Rate algorithm (also known as the Self-Calibrating Multivariate Precipitation Retrieval, or SCaMPR), over the state of Oklahoma (OK) using OK MESONET observations as ground truth. While the average annual Q2 precipitation estimates were about 35% higher than MESONET observations, there were very strong correlations between these two data sets for multiple temporal and spatial scales. Additionally, the Q2 estimated precipitation distributions over the CC, SR, and AC regions of DCSs strongly resembled the MESONET observed ones, indicating that Q2 can accurately capture the precipitation characteristics of DCSs although it has a wet bias . SCaMPR retrievals were typically three to four times higher than the collocated MESONET observations, with relatively weak correlations during a year of comparisons in 2012. Overestimates from SCaMPR retrievals that produced a high false alarm rate were primarily caused by precipitation retrievals from the anvil regions of DCSs when collocated MESONET stations recorded no precipitation. A modified SCaMPR retrieval algorithm, employing both cloud optical depth and IR temperature, has the potential to make significant improvements to reduce the SCaMPR false alarm rate of retrieved

  10. 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

  11. 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.

  12. Far-Ultraviolet Stellar Photometry

    NASA Astrophysics Data System (ADS)

    Schmidt, E. G.; Carruthers, G. R.

    1993-12-01

    During a shuttle flight in May, 1991, wide field images were obtained for 12 star fields with the NRL far-ultraviolet cameras. These cameras provide sensitivity bands with effective wavelengths of lambda eff = 1367 Angstroms and lambda eff = 1702 Angstroms. The properties of the resulting magnitude system will be described and compared with previous photometry from the OAO2, ANS and TD1 satellites. Results from several fields in the vicinity of the galactic center will be discussed.

  13. 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.

  14. An ultra-stable referenced interrogation system in the deep ultraviolet for a mercury optical lattice clock

    NASA Astrophysics Data System (ADS)

    Dawkins, S. T.; Chicireanu, R.; Petersen, M.; Millo, J.; Magalhães, D. V.; Mandache, C.; Le Coq, Y.; Bize, S.

    2010-04-01

    We have developed an ultra-stable source in the deep ultraviolet, suitable to fulfil the interrogation requirements of a future fully-operational lattice clock based on neutral mercury. At the core of the system is a Fabry-Pérot cavity which is highly impervious to temperature and vibrational perturbations. The mirror substrate is made of fused silica in order to exploit the comparatively low thermal noise limits associated with this material. By stabilizing the frequency of a 1062.6 nm Yb-doped fiber laser to the cavity, and including an additional link to LNE-SYRTE’s fountain primary frequency standards via an optical frequency comb, we produce a signal which is both stable at the 10-15 level in fractional terms and referenced to primary frequency standards. The signal is subsequently amplified and frequency-doubled twice to produce several milliwatts of interrogation signal at 265.6 nm in the deep ultraviolet.

  15. Imaging deep skeletal muscle structure using a high-sensitivity ultrathin side-viewing optical coherence tomography needle probe

    PubMed Central

    Yang, Xiaojie; Lorenser, Dirk; McLaughlin, Robert A.; Kirk, Rodney W.; Edmond, Matthew; Simpson, M. Cather; Grounds, Miranda D.; Sampson, David D.

    2013-01-01

    We have developed an extremely miniaturized optical coherence tomography (OCT) needle probe (outer diameter 310 µm) with high sensitivity (108 dB) to enable minimally invasive imaging of cellular structure deep within skeletal muscle. Three-dimensional volumetric images were acquired from ex vivo mouse tissue, examining both healthy and pathological dystrophic muscle. Individual myofibers were visualized as striations in the images. Degradation of cellular structure in necrotic regions was seen as a loss of these striations. Tendon and connective tissue were also visualized. The observed structures were validated against co-registered hematoxylin and eosin (H&E) histology sections. These images of internal cellular structure of skeletal muscle acquired with an OCT needle probe demonstrate the potential of this technique to visualize structure at the microscopic level deep in biological tissue in situ. PMID:24466482

  16. VizieR Online Data Catalog: EIS: optical deep public survey (Mignano+, 2007)

    NASA Astrophysics Data System (ADS)

    Mignano, A.; Miralles, J.-M.; da Costa, L.; Olsen, L. F.; Prandoni, I.; Arnouts, S.; Benoist, C.; Madejsky, R.; Slijkhuis, R.; Zaggia, S.

    2007-01-01

    The subdirectory "cat" includes the science grade catalogs extracted for each of the 3 regions (DEEP1, DEEP2, DEEP3), divided in 11 fields, discussed in this paper and the log-files associated with each catalog. The catalog files are in FITS format containing the primary HDU and 4 tables (MASKS, FILTER, OBJECTS and FIELDS) with the format described in Dietrich et al., 2006. The log files contain information about parameters used in the extraction process as well as parameters for quality assessment of the catalogs. The subdirectory "ima" includes includes the science grade images extracted for each of the 3 regions (DEEP1, DEEP2, DEEP3), divided in 11 fields, discussed in this paper and the log-files associated with each image. The images are in FITS format with two extensions, the first one giving the actual image and the second one being a weight map. The details of the field naming convention can be found at http://www.eso.org/science/eis (6 data files).

  17. 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.

  18. Mechanical and electronic energy eigenstates of neutral Rb atoms in deep optical lattices

    NASA Astrophysics Data System (ADS)

    Neuzner, Andreas; Koerber, Matthias; Morin, Olivier; Ritter, Stephan; Rempe, Gerhard

    2015-05-01

    Optical lattices allow for tight three-dimensional confinement of neutral atoms in quasi-harmonic potentials and have become a standard tool in experimental quantum optics. Applications range from fundamental topics like metrology to applications in quantum communication and quantum information processing. Here we present an experimental characterization of the motional and internal energy eigenstates of optically trapped 87Rb atoms. We implement different spectroscopy techniques based on non-destructive hyperfine state detection using an optical cavity. Applying these techniques, we observe and explain a series of effects like the decoupling of the hyperfine spin due to a tensor lightshift and mechanical effects associated with a small non-orthogonality of the lattice axes. Furthermore, we succeed to exploit the latter for optical cooling of a single atom into the two-dimensional mechanical groundstate in an environment with restricted optical access.

  19. 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.

  20. 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

  1. 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.

  2. The Panchromatic Hubble Andromeda Treasury. X. Ultraviolet to Infrared Photometry of 117 Million Equidistant Stars

    NASA Astrophysics Data System (ADS)

    Williams, Benjamin F.; Lang, Dustin; Dalcanton, Julianne J.; Dolphin, Andrew E.; Weisz, Daniel R.; Bell, Eric F.; Bianchi, Luciana; Byler, Nell; Gilbert, Karoline M.; Girardi, Léo; Gordon, Karl; Gregersen, Dylan; Johnson, L. C.; Kalirai, Jason; Lauer, Tod R.; Monachesi, Antonela; Rosenfield, Philip; Seth, Anil; Skillman, Eva

    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.

  3. A glass-coated tungsten microelectrode enclosing optical fibers for optogenetic exploration in primate deep brain structures.

    PubMed

    Tamura, Keita; Ohashi, Yohei; Tsubota, Tadashi; Takeuchi, Daigo; Hirabayashi, Toshiyuki; Yaguchi, Masae; Matsuyama, Makoto; Sekine, Takeru; Miyashita, Yasushi

    2012-10-15

    The optogenetic approach to primate brain circuitry has unparalleled potential for uncovering genetically and temporally resolved neuronal mechanisms of higher brain functions. In order to optogenetically investigate the large and complex primate brain, an optical-/electrical probe, or "optrode", must be inserted deeply, which requires the optrode to be not only long and stiff, but also sharp and smooth to reduce possible tissue damage. This study presents a tungsten microelectrode-based optrode that encloses optical fibers within its insulation glass. Optical fibers and a tungsten wire were tightly bound to each other and integrally coated with a smooth, thin layer of glass. This design satisfied the structural requirements for use in deep brain structures. The performance of the optrode was then examined in the thalamus of the rat and macaque monkeys which were injected with lentiviral vectors carrying the channelrhodopsin-2-enhanced yellow fluorescent protein (ChR2-EYFP) transgene. With fluorescence measurements via the optical fiber, ChR2-EYFP expression was detected clearly in vivo, which was confirmed by histological analysis in the rat. With photostimulation and extracellular recording, photo-responsive single-unit activities were isolated in the monkeys. The depth distribution of these units and the peak of the EYFP fluorescence profile overlapped consistently with each other. Thus, by developing a new probe, optogenetic methodology was successfully applied to a primate subcortical structure. This smooth glass-coated optrode is a promising tool for chronic in vivo experiments with various research targets including deep brain structures in behaving monkeys. PMID:22971353

  4. 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. PMID:27082325

  5. 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.

  6. 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

    2016-01-01

    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

  7. 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

  8. Deep turbulence effects compensation experiments with a cascaded adaptive optics system using a 3.63 m telescope.

    PubMed

    Vorontsov, Mikhail; Riker, Jim; Carhart, Gary; Gudimetla, V S Rao; Beresnev, Leonid; Weyrauch, Thomas; Roberts, Lewis C

    2009-01-01

    Compensation of extended (deep) turbulence effects is one of the most challenging problems in adaptive optics (AO). In the AO approach described, the deep turbulence wave propagation regime was achieved by imaging stars at low elevation angles when image quality improvement with conventional AO was poor. These experiments were conducted at the U.S. Air Force Maui Optical and Supercomputing Site (AMOS) by using the 3.63 m telescope located on Haleakala, Maui. To enhance compensation performance we used a cascaded AO system composed of a conventional AO system based on a Shack-Hartmann wavefront sensor and a deformable mirror with 941 actuators, and an AO system based on stochastic parallel gradient descent optimization with four deformable mirrors (75 control channels). This first-time field demonstration of a cascaded AO system achieved considerably improved performance of wavefront phase aberration compensation. Image quality was improved in a repeatable way in the presence of stressing atmospheric conditions obtained by using stars at elevation angles as low as 15 degrees. PMID:19107154

  9. UBV photometry of ER Vulpeculae

    NASA Astrophysics Data System (ADS)

    Srivastava, R. K.; Padalia, T. D.; Srivastava, J. B.

    1991-08-01

    UBV photometry of the RS CVn-type eclipsing binary system ER Vulpeculae has been presented. The period comes out to be 0.698093d. The average depths of primary and secondary minima are, respectively, 0.21 and 0.12m. The colors at various phases have been given. A dip is seen around phase 0.73P as was seen in the observations of Arevalo et al. (1988). Large scatter is present in the observations as noticed earlier, and may be due to activity of the components.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26504642

  11. 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.

  12. 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.

  13. Development of an optical beam system for deep sea data acquisition

    SciTech Connect

    Shibata, Yozo

    1994-12-31

    Remotely Operated Vehicles (ROV) are an ideal method for acquiring data from instruments located on the seabed. Electrical, acoustic or optical signals can be used to communicate with the data acquisition system. While optical signals have high capacity, the power of the optical beam decreases rapidly with distance in sea water; however, the ROV`s ability to approach the instruments eliminates this problem. To investigate a feasibility of an optical beam system for underwater data acquisition, the author has developed and manufactured a prototype data acquisition instrument which the ROV can control. Based on the communication test results, he concludes that such a system is a practical means of short-range underwater data acquisition.

  14. An adaptive threshold detector and channel parameter estimator for deep space optical communications

    NASA Technical Reports Server (NTRS)

    Arabshahi, P.; Mukai, R.; Yan, T. -Y.

    2001-01-01

    This paper presents a method for optimal adaptive setting of ulse-position-modulation pulse detection thresholds, which minimizes the total probability of error for the dynamically fading optical fee space channel.

  15. 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.

  16. Unique Search and Track Procedures Utilizing the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) Worldwide Sites

    NASA Astrophysics Data System (ADS)

    Bruck, R.; Peppard, T.

    2012-09-01

    The GEODSS Vela Search Team, in conjunction with the Air Force, developed revolutionary new procedures to search for man-made objects in deep space. In the first-ever aggressive, proactive campaign against a series of lost satellites, three GEODSS optical detachments were employed to find Vela communication satellites launched in the 1960s. These satellites, in highly eccentric orbits, had not been tracked in over 40 years. The Team exploited GEODSS telescopes and technology for a mission they were not designed to perform by employing modified optical viewing parameters and new search techniques. Using the sun to provide illumination, while modifying optical parameters, the GEODSS team found 5 lost Vela satellites and enhanced the Air Force Space Command satellite catalog. In addition, the Team developed two new tactics, techniques & procedures to capture very hard-to-track objects. Revisit time was increased from intermittent and yearly tracking to weeks or better to find 3 Velas lost for over four decades. The Joint Space Operations Center (JSPOC) analysts stated that the Vela search and tracking was a great success. Additionally, a GEODSS Tactics Development Team was the first to use a deep space observing telescope to track satellites in near earth orbits and outside of the traditional observing period. The team was able to observe and provide metric track data on the International Space Station, Hubble Space Telescope and several other satellites in Near Earth Orbits. Additionally, data was collected before the civil sunset observing period on the Phobos-Grunt re-entry and an Iridium Communications Satellite in Low Earth Orbit. The ability to observe and then successfully repeat the process was an astronomical achievement. The GEODSS team accomplishments pushed the boundaries of the GEODSS system design and proved existing capabilities that had not yet been considered. Lessons learned were established for Vela & other orbit types.

  17. 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.

  18. Vortex formation of a Bose-Einstein condensate in a rotating deep optical lattice

    SciTech Connect

    Kato, Akira; Nakano, Yuki; Kasamatsu, Kenichi; Matsui, Tetsuo

    2011-11-15

    We study the dynamics of vortex nucleation and lattice formation in a Bose-Einstein condensate in a rotating square optical lattice by numerical simulations of the Gross-Pitaevskii equation. Different dynamical regimes of vortex nucleation are found, depending on the depth and period of the optical lattice. We make an extensive comparison with the experiments by R. A. Williams et al.[Phys. Rev. Lett. 104, 050404 (2010)], especially focusing on the issues of the critical rotation frequency for the first vortex nucleation and the vortex number as a function of rotation frequency.

  19. VizieR Online Data Catalog: gr photometry of Sextans A and Sextans B (Bellazzini+, 2014)

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    The tables present deep LBT/LBC g and r photometry of the stars having image quality parameters (provided by DAOPHOTII) CHI<=2 and SHARP within magnitude-dependent contours traced to include the bulk of stellar objects. The observations were achieved on the night og 2012-02-21 with the Large Binocular Camera at the Large Binocular Telescope in binocular mode; g images were acquired with the blue arm and r images with the red arm of the telescope/camera. The astrometry and the photometry were calibrated with stars in common with SDSS-DR9 (V/139). (2 data files).

  20. Photometry of late type stars

    NASA Technical Reports Server (NTRS)

    Doherty, L. R.

    1972-01-01

    Broad band filter photometry for 57 bright stars of spectral type A2 discussed with peak instrument responses at 3320, 2980, 2460 and 1910 A. The data include nearly all usable filter observations of G, K and M types. Sampling is nearly complete for A and F giants and supergiants, with the exception of Cepheid variables. The basic results presented are relative digital counting rates obtained with a field-stop aperture of 10 minutes of arc. Characteristics of the four filter-photometer combinations and errors are discussed. Some observations require substantial correction if they are to represent the visually brightest star in the field. These corrections and the effects of interstellar reddening are discussed. The adjusted counts are then used to construct color-color diagrams and are compared to the recent SAO grid of model atmospheres.

  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. BV photometry of UX ARIETIS

    NASA Astrophysics Data System (ADS)

    Mohin, S.; Raveendran, A. V.

    1989-03-01

    Differential BV photometry of UX Ari obtained on 58 nights during 1984-1985, 1985-1986, 1986-1987, and 1987-1988 observing season is presented. It is found that (B-V) is phase dependent, with the system being reddest at the light maximum. This is interpreted as being due to the variable fractional contribution by the G5 V component to the total light at shorter wavelengths. An analysis of the available data indicates that, at larger amplitudes of the photometric wave, the brightness at maximum increases and that at minimum decreases, and both converge to DeltaV of about 1.0 mag at very low amplitudes. It implies that the low wave amplitudes are essentially due to more homogeneity in the surface distribution of spots rather than to low levels of spot activity. The variation in wave amplitude is found to be near-sinusoidal with a period around 13-14 years.

  3. TT Arietis: Spectroscopy and Photometry

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoan; Li, Zongyun; Ding, Yuerong; Zhang, Zhousheng; Li, Zili

    2002-04-01

    We report the photometry and spectroscopy of TT Arietis around the turn of the millennium, when the nova-like variable is in high state. A positive superhump since 1997 still exists. A more precise orbital period than before, 0.13755040+/-1.7×10-7 days, is established. The intensity of the Balmer emission core is found to modulate at the superhump period rather than the orbital period and 180° out of phase with continuum. The intensity of Balmer absorption wings is approximately proportional to the continuum flux. The correlation between Balmer lines and continuum provides a new clue to the study of sources of continuum and emission lines. The mass ratio of the binary is found to be in the range of 0.19+/-0.04, which lends strong support to the proposition that superhumps arise from the inner Lindblad 3:1 resonance in TT Ari, as in superoutbursts of SU UMa stars.

  4. Ultra-Deep Optical Spectroscopy with PMAS. Using the Nod-and-Shuffle Technique

    NASA Astrophysics Data System (ADS)

    Roth, Martin M.; Fechner, Thomas; Wolter, Dieter; Kelz, Andreas; Becker, Thomas

    2002-10-01

    PMAS, the Potsdam Multi-Aperture Spectrophotometer, is a new integral field spectrograph in the optical, which is optimized for good transmissionand high image quality from 350 nm to 1 μm. We present our plan to implementa CCD charge-shuffle mode to allow for beam switching with a very high degreeof sky subtraction accuracy for faint object 3-D spectroscopy.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. Transformed photometry of young stars in Cha requested

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-01-01

    Dr. Peter Abraham (Konkoly Observatory, Budapest, Hungary) requested the assistance of AAVSO observers in monitoring eight young stars in Chamaeleon in support of photometry he and his colleagues will be obtaining with the VLT/ISAAC (infrared) and Herschel Space Observatory (far-infrared) during January-February 2013. The targets are CR Cha, CT Cha, HP Cha (Glass I), VW Cha, VZ Cha, WW CHa, WX Cha, XX Cha. Calibrated, transformed VRI photometry is requested to precisely monitor changes in the optical brightness and colors of these objects. Calibration and transformation of the photometry is crucial - if all of the data are not on the same system and particularly if the colors are not transformed, it will be extremely difficult to correlate the data usefully. Previous observations indicate that the stars are highly variable. Brightness changes can be expected from a few tenths of a magnitude to up to 1-2 magnitudes on a timescale of a few days to a few weeks. Observers are asked to try to obtain one to two sets of VRI images per night. Finder charts with sequences may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  10. The Panchromatic Hubble Andromeda Treasury Survey: UV-IR Photometry of 117 Million Stars

    NASA Astrophysics Data System (ADS)

    Williams, Benjamin F.; Lang, Dustin; Dalcanton, Julianne; Dolphin, Andrew E.; Weisz, Daniel R.; Johnson, Lent C.; Byler, Nell; Gregersen, Dylan; Seth, Anil; Girardi, Leo; PHAT Survey Team

    2015-01-01

    We have measured resolved stellar photometry using HST/WFC3 and HST/ACS imaging in near ultraviolet (F275W, F336W), optical (F475W, F814W), and near infrared (F110W, F160W) with simultaneous point spread function fitting across all bands at all source positions. All images were aligned to 5-10 milliarcsecond relative accuracy and to 50 milliarcsec global 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 that are up to 2.5 magnitudes deeper when compared with color-magnitude diagrams from WFC3/IR photometry alone. This stellar catalog is the largest ever produced for equidistant sources, and is publicly available for download by the community. The quality of the photometry catalog, as well as examples of some initial results from model fitting will be discussed. PHAT is supported by HST GO-12055 administered by NASA.

  11. 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.

  12. 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

  13. 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

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

    PubMed Central

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

    2014-01-01

    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. PMID:24648222

  15. 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

    2014-05-01

    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. PMID:24648222

  16. Project NEPTUNE: an innovative, powered, fibre-optic cabled deep ocean observatory spanning the Juan de Fuca plate, NE Pacific

    NASA Astrophysics Data System (ADS)

    Barnes, C.; Delaney, J.

    2003-04-01

    NEPTUNE is an innovative facility, a deep-water cabled observatory, that will transform marine science. MARS and VENUS are deep and shallow-water test bed facilities for NEPTUNE located in Monterey Canyon, California and in southern British Columbia, respectively; both were funded in 2002. NEPTUNE will be a network of over 30 subsea observatories covering the 200,000 sq. km Juan de Fuca tectonic plate, Northeast Pacific. It will draw power via two shore stations and receive and exchange data with scientists through 3000 km of submarine fiber-optic cables. Each observatory, and cabled extensions, will host and power many scientific instruments on the surrounding seafloor, in seafloor boreholes and buoyed through the water column. Remotely operated and autonomous vehicles will reside at depth, recharge at observatories, and respond to distant labs. Continuous near-real-time multidisciplinary measurement series will extend over 30 years. Free from the limitations of battery life, ship schedules/ accommodations, bad weather and delayed access to data, scientists will monitor remotely their deep-sea experiments in real time on the Internet, and routinely command instruments to respond to storms, plankton blooms, earthquakes, eruptions, slope slides and other events. Scientists will be able to pose entirely new sets of questions and experiments to understand complex, interacting Earth System processes such as the structure and seismic behavior of the ocean crust; dynamics of hot and cold fluids and gas hydrates in the upper ocean crust and overlying sediments; ocean climate change and its effect on the ocean biota at all depths; and the barely known deep-sea ecosystem dynamics and biodiversity. NEPTUNE is a US/Canada (70/30) partnership to design, test, build and operate the network on behalf of a wide scientific community. The total cost of the project is estimated at about U.S. 250 million from concept to operation. Over U.S. 50 million has already been funded for

  17. Application of Cloud Vertical Structure to Investigate the Microphysical and Optical Properties of Cirriform, Anvil, and Deep Convective Clouds

    NASA Astrophysics Data System (ADS)

    Bates, J. J.; Young, A. H.; Curry, J. A.

    2012-12-01

    This study uses cloud vertical structure (CVS) to evaluate the optical and microphysical properties of high clouds including cirriform, anvil, and deep convection (DC) over the region between 35°S-35°N for a 1-yr period from January-December 2007. The analyses are based on integrated multisensory pixel-level observations of CVS from CloudSat/CALIPSO and Level 2 cloud data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite. Cloud products evaluated include mean cloud optical thickness, cloud effective radius, cloud-top temperature, cloud-top pressure, cloud brightness temperature, and cloud effective emissivity. Unlike other studies, high clouds investigated in this study are not determined by the International Satellite Cloud Climatology Project (ISCCP) cloud classification scheme. Instead it relies on the CloudSat 2B-CLDCLASS product which uses radar reflectivity data and also considers the spatial and horizontal cloud structure to classify cirriform, anvil, and DC clouds. Results of the study are used to evaluate the capabilities of MODIS to estimate cloud properties and identify the impacts of using CVS to classify various types of high level clouds rather than the ISCCP cloud classification scheme. Applications of the study's results include potential improvements to precipitation retrievals and the representation of cloud systems in general circulation models.

  18. 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.

  19. 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.

  20. A Detailed Study of Contamination in Deep Rapid Searches for Gravitational Wave Optical Counterparts

    NASA Astrophysics Data System (ADS)

    Cowperthwaite, Philip; Berger, Edo; Chornock, Ryan; Fong, Wen-fai

    2015-01-01

    The first direct detection of gravitational waves (GW) by the Advanced LIGO/VIRGO (aLIGO/VIRGO) collaboration is expected to occur within the next few years. In order to maximize the science gains from such a detection it is essential that we identify an electromagnetic counterpart. One of the most promising counterparts is the so-called 'kilonovae,' a fast-evolving (t ~ days) and faint (z ~ 24 AB mag) optical transient powered by the radioactive decay of r-process elements generated in the merger. However, the poor initial localization of aLIGO/VIRGO (~ 100 sq. deg.) demand the use of wide-field telescopes. Furthermore, the cadences and depths used by current and future wide-field optical surveys (e.g. PTF/ZTF, PANStarrs, LSST) are sub-optimal for kilonovae detection. We present our attempts to tackle these issues by investigating the theoretical and practical issues associated with optical follow-up of an aLIGO/VIRGO GW event. This includes a systematic study of the potential contaminant population and their impact on kilonovae detectability in simulated observations. We show that kilonovae can remain separated from contaminants by the virtue of their red colors (i - z > 0.5) and short timescales. This theoretical analysis will be tested against observations obtained by the DECam wide-field imager on the CTIO Blanco 4m telescope. These data attempt to simulate the wide area coverage (~ 70 sq. deg.) and rapid cadence (two visits per night in i,z) necessary for targeted GW follow-up and will provide an excellent test bed for understanding the practical issues associated with this endeavor. This work is supported in part by the NSF GRFP grant DGE1144152.

  1. 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

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

    PubMed

    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

  3. 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

  4. Assessment of the SFH retrieved from u'g'r'i'z' photometry using DynBaS

    NASA Astrophysics Data System (ADS)

    Mejía, A. J.; Magris, G.

    2014-10-01

    We present a progress on the evaluation of uncertainties and biases on the determination of the stellar mass, mean stellar age and dust extinction retrieved from broadband (rest-frame) u'g'r'i'z' photometry using a non-parametric SED fitting method named DynBaS (Magris et al. in prep.). We show that the so called template mismatch, can be successfully avoided, providing better recovery even if only optical broadband photometry is fitted.

  5. 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

  6. Classification of stars with WBVR photometry

    NASA Astrophysics Data System (ADS)

    Sichevskiy, S. G.; Mironov, A. V.; Malkov, O. Yu.

    2013-10-01

    We present a method of obtaining the most reliable stellar spectral type based on multi-color photometry. The method also allows us to estimate color excess EB-V and distance to the star. Approbation of the method using bright stars with known spectral classification and W BV R photometry permits to estimate its reliability. Stellar spectra models from Pickles (1998) library and Fluks et al. (1994) interstellar extinction law were used in the application of the method.

  7. 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.

  8. Coexisting localized and extended optical Bloch states in a periodic deep wire array microcavity

    NASA Astrophysics Data System (ADS)

    Löchner, Franz J. F.; Mischok, Andreas; Brückner, Robert; Lyssenko, Vadim G.; Zakhidov, Alexander A.; Fröb, Hartmut; Leo, K.

    2015-09-01

    We embed periodic SiO2 wires in an organic microcavity, producing a rectangular potential by the different optical thicknesses of the active layer due to the additional SiO2 layer. By μ -photoluminescence spectroscopy, we observe the energy dispersion of the photons and obtain discrete localized below and extended Bloch states above the potential barrier, respectively, showing that electro-magnetic waves can behave like massive particles, such as electrons, in crystal lattices. We investigate the dependencies on wire width and period and use the Kronig-Penney model to describe the photon energy dispersion, including an "effective mass" of a photon propagating through a microcavity implying polarization splitting. We obtain excellent agreement between experiment, simulation and analytical calculation.

  9. 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.

  10. Spectroscopy and photometry of the nova candidate M33N 2013-12a

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Barsukova, E. A.; Valeev, A. F.; Sholukhova, O.; Hornoch, K.; Shafter, A. W.; Henze, M.

    2014-01-01

    We report optical spectroscopy and photometry of a recent M33 nova candidate (M33N 2013-12a = PNV J01331092+3037511) detected by the Lick Observatory Supernova Search ( http://www.cbat.eps.harvard.edu/unconf/followups/J01331092+3037511.html ).

  11. 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

  12. 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.

  13. Spectroscopy and photometry of the nova M31N 2014-01a at maximum

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Barsukova, E. A.; Valeev, A. F.; Sholukhova, O.; Hornoch, K.; Shafter, A. W.; Henze, M.

    2014-01-01

    We report optical spectroscopy and photometry of the recent M31 nova candidate M31N 2014-01a (= PNV J00431362+4114469) detected by the Lick Observatory Supernova Search on 2014 Jan. 02.13 UT (http://www.cbat.eps.harvard.edu/unconf/followups/J00431362+4114469.html ) and also observed on 2014 Jan. 05.42 UT as a 16.4 mag object by T. Yusa and K. Kato (Japan). Using the Russian BTA telescope equipped with the SCORPIO spectrograph we have obtained spectra and photometry of the nova M31N 2014-01a on 2014 Jan.

  14. Li3AlSiO5: the first aluminosilicate as a potential deep-ultraviolet nonlinear optical crystal with the quaternary diamond-like structure.

    PubMed

    Chen, Xinglong; Zhang, Fangfang; Liu, Lili; Lei, Bing-Hua; Dong, Xiaoyu; Yang, Zhihua; Li, Hongyi; Pan, Shilie

    2016-02-14

    Deep-ultraviolet (deep-UV) nonlinear optical (NLO) crystals play a crucial role in modern laser frequency conversion technology. Traditionally, the exploration of deep-UV NLO crystals is mainly focused on borates, while, the use of phosphates recently opened up a novel and promising non-boron pathway for designing new deep-UV NLO crystals. Extending this pathway to aluminosilicates led to the discovery of Li3AlSiO5, the first NLO crystal in this system. It crystallizes in the polar space group Pna21 (no. 33) with a quaternary diamond-like structure composed of LiO4, AlO4 and SiO4 tetrahedral groups. The compound exhibits a deep-UV cut-off edge below 190 nm and is phase matchable with moderate powder second harmonic generation (SHG) intensity (0.8KH2PO4). The band gap calculated using PBE0 is 7.29 eV, indicating that the cut-off edge of the Li3AlSiO5 crystal can be down to 170 nm. In addition, the compound is nonhygroscopic and thermally stable up to ∼1472 K. These results suggest that Li3AlSiO5 is a potential deep-UV NLO crystal. First-principles studies were performed to elucidate the structure-property relationship of Li3AlSiO5. PMID:26788988

  15. Multicolor photometry of triple system b Per requested

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-01-01

    Dr. Bob Zavala (U.S. Naval Observatory, Flagstaff) has requested AAVSO assistance in obtaining multicolor photometry of the bright triple system b Per in order to prepare for and detect a possible eclipse of the AB components by the C component predicted for 2013 January 23. Multi-color photometric observations of 4.5V b Per are requested 2013 January 23 through February 04. Based on a revised period of 702.45 ± 0.05 days, the next time of minimum light is predicted for HJD = 2456321.35 ± 0.05 (UT 2013 January 28 20:24UT ± 1.5 hours). The eclipse may last for up to four days, so the coverage requested will provide both a baseline out-of-eclipse light curve and a multi-color eclipse light curve for analysis. Photometry is needed at the level of 0.02-0.03 magnitude or better, as the eclipse may be as deep as 0.1 magnitude. For PEP observers, V coverage, and B if possible, is requested. DSLR observers should use whatever band(s) are available to them. Finder charts may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and links.

  16. Changes on Pluto's Surface Revealed with Long Timebase Photometry

    NASA Astrophysics Data System (ADS)

    George, Erin; Buie, M.

    2013-10-01

    We are continuing to monitor the long-term photometric behavior of Pluto in order to constrain volatile surface migration. As Pluto passes near the center of the galaxy, the fields are too crowded for normal aperture photometric techniques. We approached this problem with a combination of point-spread function (PSF) photometry and optimal image subtraction (OIS). Our data are from the 0.8-m robotic telescope at Lowell Observatory, the 1-m robotic telescope at New Mexico State Observatory, and the Faulkes 2-m robotic telescope at Siding Spring, part of Las Cumbres Observatory. Our latest results add photometric data up through 2012 to the data collected since discovery. Our new reduction scheme consists of background catalogs, image subtraction using deep templates, and Pluto photometry extraction. We also use the known photometric properties of Charon determined with HST to remove Charon's contribution from old and new data and compare these results with the HST data where Pluto is measured by itself. Data since 2002 show marked departures from the behavior prior to that time. These results provide clear evidence for time evolution of Pluto's surface albedo. We will present these results along with implications for present-day processes that are altering the surface of Pluto. This work also provides crucial insight into the effort required to provide ground-based support observations for the upcoming New Horizons flyby of Pluto in 2015. Support for this work was provided by NASA Planetary Astronomy Program, grant number NNX09AB43G.

  17. 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.

  18. 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.

  19. HST photometry of the trapezium cluster

    NASA Technical Reports Server (NTRS)

    Prosser, Charles F.; Stauffer, John R.; Hartmann, Lee; Soderblom, David R.; Jones, Burton F.; Werner, Michael W.; Mccaughrean, Mark J.

    1994-01-01

    We have obtained images of 11 fields in the Trapezium cluster with the Planetary Camera (PC) of the Hubble Space Telescope (HST) in order to extend Herbig & Terndrup's (1986) study of this prototype, dense embedded cluster to fainter magnitudes than is possible from the ground. Using these images, we have identified 319 stars within an area of approximately 12 sq arc min corresponding roughly to a volume of approximately 0.065 cu pc assuming the cluster is approximately spherically symmetric. Our completeness limits for star identification in V-band and I-band images are V approximately = 20 and I(sub c) approximately = 19 respectively, corresponding to a mass limit of approximately 0.15 solar mass if the faintest stars have the same average A(sub v) as that estimated for the brighter stars in the cluster. We have compared the V versus V-I color-magnitude diagram derived from the HST photometry to new theoretical isochrones. Star formation in the Trapezium appears to be remarkably coeval, with greater than or = 80% of the stars having inferred ages less than 1 Myr. Over the somewhat limited mass range of the observations, there is no evidence for 'bimodal' star formation-the high- and low-mass stars appear to have the same ages. The sharp cores of the HST images and the small angular size of the PC pixels has allowed us to identify 35 new visual binaries in the cluster with separations from approximately 0.06 arc sec (approximately 26 AU) to approximately 1.0 arc sec (approximately 440 AU). For the range of binary separations that we are sensitive to, the observed binary frequency for the Trapezium is essentially identical to that estimated for field low-mass stars by Duquennoy & Mayor (1991). The most straightfoward inference from this result is that binaries in this separation are unlikely to be formed by a tidal capture process. We have also identified three stars which have associated compact nebulosity visible in the HST images. One of these star + nebulosity

  20. Flaring on RS CVn systems: Results from EUVE Photometry

    NASA Astrophysics Data System (ADS)

    Osten, R. A.; Brown, A.; Ayres, T. R.

    We present broadband EUV photometry for a sample of RS CVn systems observed with the Deep Survey Spectrometer and Right Angle Program (RAP) Scanners on the Extreme Ultraviolet Explorer (EUVE). We have developed robust data analysis and light curve software for the interpretation of these data. Large-scale flaring activity is seen on 15 of the 18 systems studied. These binaries cover a range in orbital period of 0.7 days to 21 days and include a mixture of giant, subgiant, and dwarf luminosity classes. For many systems the photometric coverage extends over several orbital periods and flaring is unambiguously characterized. We present statistics on the distribution of variability in the survey. Correlations of flaring with binary properties are examined.

  1. Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry

    NASA Astrophysics Data System (ADS)

    Sullivan, Peter W.; Croll, Bryce; Simcoe, Robert A.

    2013-09-01

    We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (<= 1 m) telescopes capable of precise (< 1 mmag) infrared photometry of relatively bright targets. The camera is constructed around the 640 × 512 pixel APS640C sensor built by FLIR Electro-Optical Components. We designed custom analog-to-digital electronics for maximum stability and minimum noise. The InGaAs dark current halves with every 7°C of cooling, and we reduce it to 840 e- s-1 pixel-1 (with a pixel-to-pixel variation of ± 200 e- s-1 pixel-1) by cooling the array to -20°C. Beyond this point, glow from the readout dominates. The single-sample read noise of 149 e- is reduced to 54 e- through up-the-ramp sampling. Laboratory testing with a star field generated by a lenslet array shows that two-star differential photometry is possible to a precision of 631 ± 205 ppm (0.68 mmag) hr-1/2 at a flux of 2.4 × 104 e- s-1. Employing three comparison stars and decorrelating reference signals further improves the precision to 483 ± 161 ppm (0.52 mmag) hr-1/2. Photometric observations of HD80606 and HD80607 (J = 7.7 and 7.8) in the Y band shows that differential photometry to a precision of 415 ppm (0.45 mmag) hr-1/2 is achieved with an effective telescope aperture of 0.25 m. Next-generation InGaAs detectors should indeed enable Poisson-limited photometry of brighter dwarfs with particular advantage for late-M and L types. In addition, one might acquire near-infrared photometry simultaneously with optical photometry or radial velocity measurements to maximize the return of exoplanet searches with small telescopes.

  2. Glory revealed in disk-integrated photometry of Venus

    NASA Astrophysics Data System (ADS)

    García Muñoz, A.; Pérez-Hoyos, S.; Sánchez-Lavega, A.

    2014-06-01

    Context. Reflected light from a spatially unresolved planet yields unique insight into the overall optical properties of the planet cover. Glories are optical phenomena caused by light that is backscattered within spherical droplets following a narrow distribution of sizes; they are well known on Earth as localised features above liquid clouds. Aims: Here we report the first evidence for a glory in the disk-integrated photometry of Venus and, in turn, of any planet. Methods: We used previously published phase curves of the planet that were reproduced over the full range of phase angles with model predictions based on a realistic description of the Venus atmosphere. We assumed that the optical properties of the planet as a whole can be described by a uniform and stable cloud cover, an assumption that agrees well with observational evidence. Results: We specifically show that the measured phase curves mimic the scattering properties of the Venus upper-cloud micron-sized aerosols, also at the small phase angles at which the glory occurs, and that the glory contrast is consistent with what is expected after multiple scattering of photons. In the optical, the planet appears to be brighter at phase angles of ~11-13° than at full illumination; it undergoes a maximum dimming of up to ~10% at phases in between. Conclusions: Glories might potentially indicate spherical droplets and, thus, extant liquid clouds in the atmospheres of exoplanets. A prospective detection will require exquisite photometry at the small planet-star separations of the glory phase angles. Appendices are available in electronic form at http://www.aanda.org

  3. 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.

  4. An Improved Method for Differential Photometry

    NASA Astrophysics Data System (ADS)

    Fernández Fernández, Javier; Chou, Dean-Yi; Pan, Yen-Chen; Wang, Li-Hang

    2012-05-01

    We developed a method to improve the conventional differential photometry by using many auxiliary stars to reduce noise in the reference light curve, which is used to calibrate the light curve of the target star. The data used in this study are taken with the Taiwan Automated Telescope network. The light curves of two δ Scuti, HD 163032 and V830 Her, are shown here as examples. The results are compared with four other methods: conventional differential photometry; ensemble photometry; the method of Tamuz, Mazeh, & Zucker; and trend filtering algorithm. The light curve computed with our method is smoother than the other four methods, while preserving the pulsational signals. The mode frequencies determined from the light curve from our method also has a higher S/N and lower error in comparison with other methods.

  5. 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

    2015-12-01

    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. PMID:26459262

  6. Photometry of the old nova HZ Pup

    NASA Astrophysics Data System (ADS)

    Cassanelli, Tomas; Abbott, Tim

    2016-01-01

    This study of the old nova HZ Pup involved obtaining image data, removing the instrumental signature, performing photometry on the stellar images present, and generating light curves. Relative photometry between the target star and other stars in the image was used to remove atmospheric effects. A periodogram of this light curve shows the historically known periodicity close to 20 minutes. However, other periodicities are also present and it is not clear from the data which are real and which are artifacts of the sampling. These data will be combined with data from other telescopes collected contemporaneously in order to resolve this ambiguity.

  7. 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.

  8. A SEARCH FOR LYMAN BREAK GALAXIES IN THE CHANDRA DEEP FIELD SOUTH USING SWIFT ULTRAVIOLET/OPTICAL TELESCOPE

    SciTech Connect

    Basu-Zych, Antara R.; Hornschemeier, Ann E.; Hoversten, Erik A.; Gronwall, Caryl; Lehmer, Bret E-mail: Ann.Hornschemeier@nasa.gov E-mail: caryl@astro.psu.edu

    2011-10-01

    While the Swift satellite is primarily designed to study gamma-ray bursts, its ultraviolet and optical imaging and spectroscopy capabilities are also being used for a variety of scientific programs. In this study, we use the UV/Optical Telescope (UVOT) instrument on board Swift to discover 0.5 < z < 2 Lyman break galaxies (LBGs). UVOT has covered {approx}266 arcmin{sup 2} at >60 ks exposure time, achieving a limiting magnitude of u < 24.5, in the Chandra Deep Field South (CDF-S). Applying UVOT near-ultraviolet color selection, we select 50 UV-dropouts from this UVOT CDF-S data. We match the selected sources with available multiwavelength data from Great Observatories Origins Deep Survey (GOODS) South, Multiwavelength Survey by Yale-Chile, and COMBO-17 to characterize the spectral energy distributions for these galaxies and determine stellar masses, star formation rates (SFRs), and dust attenuations. We compare these properties for LBGs selected in this paper versus z {approx} 3 LBGs and other CDF-S galaxies in the same redshift range (0.5 < z < 2), identified using photometric redshift techniques. The z {approx} 1 LBGs have stellar masses of (logM{sub *}/M{sub sun}) = 9.4 {+-} 0.6, which is slightly lower than z {approx} 3 LBGs ((logM{sub *}/Ms{sub un}) = 10.2 {+-} 0.4) and slightly higher compared with the z {approx} 1 CDF-S galaxies ((logM{sub *}/M{sub sun}) = 8.7 {+-} 0.7). Similarly, our sample of z {approx} 1 LBGs has SFRs (derived using both ultraviolet and infrared data, where available) of (logSFR/(M{sub sun} yr{sup -1})) = 0.7 {+-} 0.6, nearly an order of magnitude lower than z {approx} 3 LBGs ((logSFR/M{sub sun} yr{sup -1}) = 1.5 {+-} 0.4), but slightly higher than the comparison z {approx} 1 sample of CDF-S galaxies ((logSFR/M{sub sun} yr{sup -1}) = 0.2 {+-} 0.7). We find that our z {approx} 1 UV-dropouts have (A{sub FUV}) = 2.0 {+-} 1.0, which is higher than z {approx} 3 LBGs ((A{sub FUV}) = 1.0 {+-} 0.5), but similar to the distribution of dust

  9. Keck Spectroscopy and NICMOS Photometry of a Redshift Z = 5.60 Galaxy

    NASA Astrophysics Data System (ADS)

    Weymann, Ray J.; Stern, Daniel; Bunker, Andrew; Spinrad, Hyron; Chaffee, Frederic H.; Thompson, Rodger I.; Storrie-Lombardi, Lisa J.

    1998-10-01

    We present Keck Low Resolution Imaging Spectrometer spectroscopy along with Near-Infrared Camera and Multiobject Spectrometer (NICMOS) F110W (~J) and F160W (~H) images of the galaxy HDF 4-473.0 in the Hubble Deep Field (HDF), with a detection of an emission line consistent with Lyα at a redshift of z=5.60. Attention to this object as a high-redshift galaxy was first drawn by Lanzetta, Yahil, & Fernandez-Soto and appeared in their initial list of galaxies with redshifts estimated from the Wide Field Planetary Camera 2 (WFPC2) HDF photometry. It was selected by us for spectroscopic observation, along with others in the HDF, on the basis of the NICMOS F110W and F160W and WFPC2 photometry. For H0=65 km s-1 Mpc-1 and q0=0.125, the use of simple evolutionary models along with the F814W (~I), F110W, and F160W magnitudes allow us to estimate the star formation rate (~13 Msolar yr-1). The colors suggest a reddening of E(B-V)~0.06. The measured flux in the Lyα line is approximately 1.0×10-17 ergs cm-2 s-1, and the rest-frame equivalent width, correcting for the absorption caused by intervening H I, is ~90 Å. The galaxy is compact and regular, but resolved, with an observed FWHM of ~0.44". Simple evolutionary models can accurately reproduce the colors, and these models predict the Lyα flux to within a factor of 2. Using this object as a template shifted to higher redshifts, we calculate the magnitudes through the F814W and two NICMOS passbands for galaxies at redshifts 6Optical data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W. M. Keck Foundation. The near-infrared observations were obtained with the Near-Infrared Camera and Multiobject Spectrometer on the NASA/ESA Hubble Space Telescope, which is

  10. 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 %.

  11. 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

  12. 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. ...

  13. Photometry of Faint Wide Doubles in Hydra

    NASA Astrophysics Data System (ADS)

    Knapp, Wilfried; Thuemen, Chris; Gould, Ross

    2015-11-01

    Images of several double stars in Hydra published on the "Double Star Imaging Project" Yahoo Group page suggest magnitude issues compared with the corresponding WDS catalog data per end of 2014. Taking additional images with V and B filters enabled photometry for these pairs, suggesting significant corrections to the old data in WDS.

  14. Walraven photometry of nearby southern OB associations

    NASA Technical Reports Server (NTRS)

    De Geus, E. J.; Lub, J.; Van De Grift, E.

    1990-01-01

    Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars in the regions of five nearby southern OB associations: Scorpio Centaurus (Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2. Derived V and (B - V) in the Johnson system are included.

  15. Detecting Problematic Observer Offsets in Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Calderwood, T.

    2014-06-01

    A heuristic method, based upon histogram analysis, is presented for detecting offsets pervasive enough to be symptoms of problematic observing technique or calibration. This method is illustrated by a study of scatter in AAVSO photoelectric photometry (PEP) for five well-observed variable stars.

  16. Detecting Problematic Observer Offsets in Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Calderwood, Tom

    2014-05-01

    A heuristic method, based upon histogram analysis, is presented for detecting offsets pervasive enough to be symptoms of problematic observing technique or calibration. This method is illustrated by a study of scatter in AAVSO photoelectric photometry (PEP) for five well-observed variable stars.

  17. TRIPP: Time Resolved Imaging Photometry Package

    NASA Astrophysics Data System (ADS)

    Geckeler, Ralf D.; Schuh, Sonja; Dreizler, Stefan; Deetjen, Jochen; Gleissner, Thomas; Risse, Patrick; Rauch, Thomas; Göhler, Eckart; Hügelmeyer, Simon; Husser, Tim-Oliver; Israel, Holger; Benlloch-Garcia, Sara; Pottschmidt, Katja; Wilms, Jörn

    2014-05-01

    Written in IDL, TRIPP performs CCD time series reduction and analysis. It provides an on-line check of the incoming frames, performs relative aperture photometry and provides a set of time series tools, such as calculation of periodograms including false alarm probability determination, epoc folding, sinus fitting, and light curve simulations.

  18. 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.

  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. THE ARAUCARIA PROJECT: THE DISTANCE TO THE SCULPTOR GALAXY NGC 247 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES

    SciTech Connect

    Gieren, Wolfgang; Pietrzynski, Grzegorz; Szewczyk, Olaf; Soszynski, Igor; Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A.; Storm, Jesper; Minniti, Dante; GarcIa-Varela, Alejandro E-mail: szewczyk@astro-udec.cl E-mail: soszynsk@astrouw.edu.pl E-mail: kud@ifa.hawaii.edu E-mail: jstorm@aip.de

    2009-08-01

    We have obtained deep near-infrared images in J and K filters of four fields in the Sculptor Group spiral galaxy NGC 247 with the ESO VLT and Infrared Spectrometer and Array Camera. For a sample of 10 Cepheids in these fields, previously discovered by GarcIa-Varela et al. from optical wide-field images, we have determined mean J and K magnitudes and have constructed the period-luminosity (PL) relations in these bands. Using the near-infrared PL relations together with those in the optical V and I bands, we have determined a true distance modulus for NGC 247 of 27.64 mag, with a random uncertainty of {+-}2% and a systematic uncertainty of {approx}4% which is dominated by the effect of unresolved stars on the Cepheid photometry. The mean reddening affecting the NGC 247 Cepheids of E(B - V) = 0.18 {+-} 0.02 mag is mostly produced in the host galaxy itself and is significantly higher than what was found in the previous optical Cepheid studies in NGC 247 of our own group, and Madore et al., leading to a 7% decrease in the previous optical Cepheid distance. As in other studies of our project, the distance modulus of NGC 247 we report is tied to an assumed Large Magellanic Cloud distance modulus of 18.50. Comparison with other distance measurements to NGC 247 shows that the present IR-based Cepheid distance is the most accurate among these determinations. With a distance of 3.4 Mpc, NGC 247 is about 1.5 Mpc more distant than NGC 55 and NGC 300, two other Sculptor Group spirals analyzed before with the same technique by our group.

  1. The Araucaria Project: The Distance to the Sculptor Galaxy NGC 247 from Near-Infrared Photometry of Cepheid Variables

    NASA Astrophysics Data System (ADS)

    Gieren, Wolfgang; Pietrzyński, Grzegorz; Soszyński, Igor; Szewczyk, Olaf; Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A.; Storm, Jesper; Minniti, Dante; García-Varela, Alejandro

    2009-08-01

    We have obtained deep near-infrared images in J and K filters of four fields in the Sculptor Group spiral galaxy NGC 247 with the ESO VLT and Infrared Spectrometer and Array Camera. For a sample of 10 Cepheids in these fields, previously discovered by García-Varela et al. from optical wide-field images, we have determined mean J and K magnitudes and have constructed the period-luminosity (PL) relations in these bands. Using the near-infrared PL relations together with those in the optical V and I bands, we have determined a true distance modulus for NGC 247 of 27.64 mag, with a random uncertainty of ±2% and a systematic uncertainty of ~4% which is dominated by the effect of unresolved stars on the Cepheid photometry. The mean reddening affecting the NGC 247 Cepheids of E(B - V) = 0.18 ± 0.02 mag is mostly produced in the host galaxy itself and is significantly higher than what was found in the previous optical Cepheid studies in NGC 247 of our own group, and Madore et al., leading to a 7% decrease in the previous optical Cepheid distance. As in other studies of our project, the distance modulus of NGC 247 we report is tied to an assumed Large Magellanic Cloud distance modulus of 18.50. Comparison with other distance measurements to NGC 247 shows that the present IR-based Cepheid distance is the most accurate among these determinations. With a distance of 3.4 Mpc, NGC 247 is about 1.5 Mpc more distant than NGC 55 and NGC 300, two other Sculptor Group spirals analyzed before with the same technique by our group. Based on observations obtained with the ESO VLT for Large Programme 171.D-0004.

  2. Photometry of variable AFGL sources

    NASA Technical Reports Server (NTRS)

    Jones, Terry Jay; Bryja, C. O.; Gehrz, Robert D.; Harrison, Thomas E.; Johnson, Joni J.

    1990-01-01

    Results of infrared photometric observations of 63 AFGL sources over the past 9 years are presented. Using these data together with previous measurements of these stars, pulsation periods and mean photometric characteristics are determined. These stars are found to lie midway between optically identified Mira variables and the radio-luminous OH/IR stars in their period distribution and photometric properties. For the sample as a whole, there is no evidence for sudden or transient behavior such as a switch in pulsation mode. Rather, these stars suggest rapid, but continuous, evolution from shorter period Miras with weak mass loss to longer periods and larger mass-loss rates. The carbon-rich stars in the sample have the same period distribution as the oxygen-rich stars. None of the carbon stars have periods as long as those of the very long period radio-luminous OH/IR stars.

  3. FRAM telescope - monitoring of atmospheric extinction and variable star photometry

    NASA Astrophysics Data System (ADS)

    Jurysek, J.; Honkova, K.; Masek, M.

    2015-02-01

    The FRAM (F/(Ph)otometric Robotic Atmospheric Monitor) telescope is a part of the Pierre Auger Observatory (PAO) located near town Malargüe in Argentina. The main task of the FRAM telescope is the continuous night - time monitoring of the atmospheric extinction and its wavelength dependence. The current methodology of the measurement of a atmospheric extinction and for instrumentation properties also allows simultaneous observation of other interesting astronomical targets. The current observations of the FRAM telescope are focused on the photometry of eclipsing binaries, positional refinement of minor bodies of the Solar system and observations of optical counterparts of gamma ray bursts. In this contribution, we briefly describe the main purpose of the FRAM telescope for the PAO and we also present its current astrono mical observing program.

  4. 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.

  5. VizieR Online Data Catalog: BVI photometry of NGC 2547 (Naylor+, 2002)

    NASA Astrophysics Data System (ADS)

    Naylor, T.; Totten, E. J.; Jeffries, R. D.; Pozzo, M.; Devey, C. R.; Thompson, S. A.

    2002-11-01

    The catalogues have been created using the optimal photometry algorithm described in Naylor (1998MNRAS.296..339N) and Naylor et al. (2002MNRAS.335..291N, this paper). Further information is also available from Tim Naylor's optimal photometry page ( http://www.astro.ex.ac.uk/people/timn/Photometry/description.html ). The catalogues are primarily in what is called cluster format, though there are occasional variations where they are needed. There is a deep survey (Table 3), a shallower, but wider area survey (Table 4), and the combination of these (Table 5). Extracted from the deep catalogue are tables of members of the cluster derived using either the D'Antona & Mazzitelli (1997MmSAI..68..807D) isochrones (Table 6). or the Siess (2000A&A...358..593S) isochrones (Table 7). These catalogues are the result of a collaboration between teams within the Exeter Astrophysics Group led by Tim Naylor, and the Keele Astrophysics Group led by Rob Jeffries. The contributors to the currently available catalogues are Tina Devey, Monica Pozzo (now at Imperial), Simon Thompson and Ed Totten. (6 data files).

  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. Infrared Photometry for Automated Telescopes: Passband Selection

    NASA Astrophysics Data System (ADS)

    Milone, Gene; Young, Andrew T.

    2011-03-01

    The high precision that photometry in the near and intermediate infrared region can provide has not been achieved, partly because of technical challenges (including cryogenics, which most IR detectors require), and partly because the filters in common use are not optimized to avoid water-vapor absorptions, which are the principal impediment to precise ground-based IR photometry. We review the IRWG filters that achieve this goal, and the trials that were undertaken to demonstrate their superiority. We focus especially on the near IR set and, for high elevation sites, the passbands in the N window. We also discuss the price to be paid for the improved precision, in the form of lower throughput, and why it should be paid: to achieve not only higher precision (i.e., improved signal-to-noise ratio), but also lower extinction, thus producing higher accuracy in extra-atmospheric magnitudes. The edges of the IRWG passbands are not defined by the edges of the atmospheric windows: therefore, they admit no flux from these (constantly varying) edges. The throughput cost and the lack of a large body of data already obtained in these passbands are principal reasons why the IRWG filters are not in wide use at observatories around the world that currently do IR work. Yet a measure of the signal-to-noise ratio varies inversely with both extinction and with a measure of the Forbes effect. So, the small loss of raw throughput is recouped in signal-to-noise gain. We illustrate these points with passbands of both near and intermediate IR passbands. There is also the matter of cost for small production runs of these filters; reduced costs can be realized through bulk orders with uniform filter specifications. As a consequence, the near-IR IRWG passbands offer the prospect of being able to do photometry in those passbands at both high and low elevation sites that are capable of supporting precise photometry, thereby freeing infrared photometry from the need to access exclusively high and

  8. VEGAS: A VST Early-type GAlaxy Survey. I. Presentation, wide-field surface photometry, and substructures in NGC 4472

    NASA Astrophysics Data System (ADS)

    Capaccioli, Massimo; Spavone, Marilena; Grado, Aniello; Iodice, Enrichetta; Limatola, Luca; Napolitano, Nicola R.; Cantiello, Michele; Paolillo, Maurizio; Romanowsky, Aaron J.; Forbes, Duncan A.; Puzia, Thomas H.; Raimondo, Gabriella; Schipani, Pietro

    2015-09-01

    Context. We present the VST Early-type GAlaxy Survey (VEGAS), which is designed to obtain deep multiband photometry in g,r,i, of about one hundred nearby galaxies down to 27.3, 26.8, and 26 mag/arcsec2 respectively, using the ESO facility VST/OmegaCAM. Aims: The goals of the survey are 1) to map the light distribution up to ten effective radii, re; 2) to trace color gradients and surface brightness fluctuation gradients out to a few re for stellar population characterization; and 3) to obtain a full census of the satellite systems (globular clusters and dwarf galaxies) out to 20% of the galaxy virial radius. The external regions of galaxies retain signatures of the formation and evolution mechanisms that shaped them, and the study of nearby objects enables a detailed analysis of their morphology and interaction features. To clarify the complex variety of formation mechanisms of early-type galaxies (ETGs), wide and deep photometry is the primary observational step, which at the moment has been pursued with only a few dedicated programs. The VEGAS survey has been designated to provide these data for a volume-limited sample with exceptional image quality. Methods: In this commissioning photometric paper we illustrate the capabilities of the survey using g- and i-band VST/OmegaCAM images of the nearby galaxy NGC 4472 and of smaller ETGs in the surrounding field. Results: Our surface brightness profiles reach rather faint levels and agree excellently well with previous literature. Genuine new results concern the detection of an intracluster light tail in NGC 4472 and of various substructures at increasing scales. We have also produced extended (g - i) color profiles. Conclusions: The VST/OmegaCAM data that we acquire in the context of the VEGAS survey provide a detailed view of substructures in the optical emission from extended galaxies, which can be as faint as a hundred times below the sky level. Appendices are available in electronic form at http://www.aanda.org

  9. 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.

  10. Photometry with Multi-anode Microchannel Arrays (mamas) and Charge Injection Devices (cids)

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1984-01-01

    The characteristics of two kinds of detectors are summarized with emphasis on those aspects that would affect their use in high accuracy astronomical photometry. The first type, the multianode microchannel arrays (MAMA), are a family of pulse counting array detectors. Components and operation principles are reviewed and quantum efficiency, noise characteristics, and dynamic range characteristics are described. The second type, charge injection devices (CID), are discussed in reference to their applicability to photometric detection at optical wavelengths.

  11. 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.

  12. Narrow band photometry of selected asteroids

    NASA Technical Reports Server (NTRS)

    Rajamohan, R.; Bhargavi, S. G.

    1992-01-01

    The CCD photometry of selected asteroids was carried out to check for possible cometary activity in them. To distinguish the asteroids with possible cometary activity from those of the main belt, each object of interest was observed in two filters; one centered on the C2 emission band at 5140A (90A bandpass) and the other centered on the nearby continuum at 4845A (65A bandpass). None of the observed asteroids appear to have any C2 emission.

  13. 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.

  14. 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.

  15. 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.

  16. RR Lyrae Star Metallicities From Caby Photometry

    NASA Astrophysics Data System (ADS)

    Baird, Scott R.

    1996-11-01

    Ten RR Lyr stars have been observed at different pulsational phases with Caby photoelectric photometry to calibrate the response of this system to RR Lyr metallicity. As has been done for nonvariable stars, the data are displayed in a color-color diagram of hk vs b-y, where hk=(Ca-b)-(b-y). It is found that the system is much more sensitive to metal abundance than the Stromgren m1 index, and that the system retains good sensitivity even at the hottest phases of pulsation. The data produce lines of constant metallicity on the hk/b-y diagram which are single valued with respect to both b-y and hk. Therefore Caby photometry gives a metallicity which is independent of pulsational phase, a distinct advantage over ΔS and other techniques used to find RR Lyr abundances. This phase independence probably arises from the fact that Caby photometry is concerned largely with total absorption from the Ca K and H lines and the b - y continuum, and not the specific shapes of the hydrogen lines, which can be affected by changes in surface gravity as a function of phase in the pulsation and by emission near maximum light. The metallicity of the RRc star V7S3 Cen is determined to be -0.69±0.2 dex using the Caby technique.

  17. 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.

  18. 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

  19. Deep Near-IR Observations of the Globular Cluster M4: Hunting for Brown Dwarfs

    NASA Astrophysics Data System (ADS)

    Dieball, A.; Bedin, L. R.; Knigge, C.; Rich, R. M.; Allard, F.; Dotter, A.; Richer, H.; Zurek, D.

    2016-01-01

    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.

  20. Optically investigating Nd3+-Yb3+ cascade sensitized upconversion nanoparticles for high resolution, rapid scanning, deep and damage-free bio-imaging

    PubMed Central

    Zhao, Yuxiang; Zhan, Qiuqiang; Liu, Jing; He, Sailing

    2015-01-01

    The rapid development of upconversion nanoparticles (UCNPs) has been facing with a great challenge: intense emission, fast scanning, and deep imaging require high-power light irradiation with minimized heating effect (the intrinsic 975-nm excitation of Yb3+-sensitized UCNPs have overheating problem). By shifting the excitation peak from 975 nm to 795 nm, Nd3+-Yb3+ cascade sensitized upconversion nanoparticles (Nd-UCNPs) with minimized heating effect were reported as the new generation UCNPs. For the first time, within two optically modeled applications in vitro and in vivo, the damage outcomes under long time high power laser excitation were solidly calculated, complementing the damage-free study of Nd-UCNPs. The higher resolution (20% improvement) and five times faster scanning microscopy were successfully performed using Nd-UCNPs under safety laser power level. The computational results showed the Nd3+-Yb3+ energy transfer efficiency would not compromise the deep imaging ability, and the red (650-nm) emission is worth to be enhanced for deep tissue imaging. PMID:25798308

  1. Investigating Correlations Between Satellite-Derived Aerosol Optical Depth And Ground PM2.5 Measurements in Californias San Joaquin Valley with MODIS Deep Blue

    NASA Astrophysics Data System (ADS)

    Justice, E.; Huston, L.; Krauth, D.; Mack, J.; Oza, S.; Strawa, A.; Legg, M.; Schmidt, C.; Skiles, J.

    2008-12-01

    Air quality in the San Joaquin Valley has failed to meet state and federal particulate matter (PM) attainment standards for the past several years. Air quality agencies currently use ground sensors to monitor the region's air. While this method provides accurate information at specific locations, it does not provide a clear indication of conditions over large regions. Measurements from satellite imagery have the potential to provide timely air quality data for large swaths of land. While previous studies show strong correlations between MODIS-derived Aerosol Optical Depth (AOD) and surface PM measurements on the East Coast of the United States, only weak correlations have been found in the West. Specific causes of this discrepancy have not been identified, nor has a solution been found. This study compares hourly and daily surface PM measurements to both traditional and Deep Blue-derived Aqua MODIS AOD data. Deep Blue is a newly developed algorithm that was recently applied to all Aqua MODIS data. Additionally, we analyzed the effects of relative humidity, surface reflectance, and aerosol vertical distribution, from CALIPSO's CALIOP sensor, on differences in PM and AOD measurements. Results show hourly PM2.5 data improved correlations with satellite AOD values. Also PM2.5 data, corresponding to sites in Bakersfield and Fresno, correlate better with Deep Blue-derived AOD values than with traditional MODIS AOD. Further investigation into the affects of seasonal variation, particle distribution and speciation is needed.

  2. Deep level defects throughout the bandgap of (010) β-Ga2O3 detected by optically and thermally stimulated defect spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Farzana, E.; Arehart, A. R.; Ringel, S. A.

    2016-02-01

    Deep level optical spectroscopy (DLOS) and deep level transient spectroscopy (DLTS) measurements performed on Ni/β-Ga2O3 Schottky diodes fabricated on unintentionally doped (010) substrates prepared by edge-defined film-fed growth revealed a rich spectrum of defect states throughout the 4.84 eV bandgap of β-Ga2O3. Five distinct defect states were detected at EC - 0.62 eV, 0.82 eV, 1.00 eV, 2.16 eV, and 4.40 eV. The EC - 0.82 eV and 4.40 eV levels are dominant, with concentrations on the order of 1016 cm-3. The three DLTS-detected traps at EC - 0.62 eV, 0.82 eV, and 1.00 eV are similar to traps reported in Czochralski-grown β-Ga2O3, [K. Irmscher et al., J. Appl. Phys. 110, 063720 (2011)], suggesting possibly common sources. The DLOS-detected states at EC - 2.16 eV and 4.40 eV exhibit significant lattice relaxation effects in their optical transitions associated with strongly bound defects. As a consequence of this study, the Ni/β-Ga2O3 (010) Schottky barrier height was determined to be 1.55 eV, with good consistency achieved between different characterization techniques.

  3. Magnetic activity on V889 Herculis. Combining photometry and spectroscopy

    NASA Astrophysics Data System (ADS)

    Järvinen, S. P.; Korhonen, H.; Berdyugina, S. V.; Ilyin, I.; Strassmeier, K. G.; Weber, M.; Savanov, I.; Tuominen, I.

    2008-09-01

    Aims: In this paper we analyse photometric and spectroscopic observations of the young active dwarf V889 Her. We present new surface temperature maps, and compare them to earlier published Doppler maps, as well as to the results obtained from long-term photometry. Methods: The light curve inversions and surface temperature maps were obtained using the Occamian approach inversion technique. Results: The 12 years of photometric records on V889 Her suggest a possible photometric cycle of approximately 9 years. Variability on this time scale is detected in the maximum, minimum, and mean photometric magnitudes. The spots prefer to concentrate on two active longitudes that are approximately 180° apart. Furthermore, one flip-flop event, i.e., a sudden change of the dominant active longitude by 180°, is detected at the time of the global maximum activity. The wings of the Ca II 8662 Å indicate that the quiet photosphere of the V889 Her is similar to the one of the present Sun supporting earlier determined atmospheric parameters, while the chromosphere of V889 Her shows signs of much stronger activity. The temperature maps reveal that the polar regions are covered by spots, which are about 1500 K cooler than the quiet photosphere. The mean spot latitude varies slightly with time. It appears that the spot latitudes from our Doppler images and the spot migration rates revealed by photometry indicate a weaker differential rotation than reported earlier, but in the same (solar-like) direction. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Table [see full textsee full textsee full text] and Figs. [see full textsee full textsee full text]-[see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Scintillation Noise in Exoplanet Transit Photometry

    NASA Astrophysics Data System (ADS)

    Föhring, Dóra; Wilson, Richard; Osborn, James; Dhillon, Vik

    2015-04-01

    Transit photometry is a powerful technique for studying exoplanets. Transit observations from the ground of targets of magnitude V= 10 or brighter, however, are limited by scintillation noise due to Earth's atmosphere. Through turbulence profiling using instruments such as the stereo-SCIDAR, we have shown to able to accurately model scintillation noise, which is essential in order to fully account for the error budget of the observation. Through numerical modelling we find that employing scintillation reducing techniques enables an improvement of a factor between 1.36 — 1.6 on the astrophysical parameters.

  10. Charles Nordmann and Multicolour Stellar Photometry

    NASA Astrophysics Data System (ADS)

    Lequeux, James

    2010-11-01

    Charles Nordmann (1881-1940), an astronomer at the Paris Observatory, was the first to determine the effective temperature of stars with his photometre heterochrome, simultaneously and independently of Rosenberg, Wilsing and Scheiner in Germany. He is also the remote precursor of the multicolour photometry of Johnson and Morgan. In spite of the quality of his temperature determinations, which were as good or better than those made by spectrophotometry, he rapidly fell into oblivion because of some failures in his scientific work. We examine his activity in the international context of the time, and explain why he has been forgotten, to be rediscovered only recently.

  11. Time Series Photometry of KZ Lacertae

    NASA Astrophysics Data System (ADS)

    Joner, Michael D.

    2016-01-01

    We present BVRI time series photometry of the high amplitude delta Scuti star KZ Lacertae secured using the 0.9-meter telescope located at the Brigham Young University West Mountain Observatory. In addition to the multicolor light curves that are presented, the V data from the last six years of observations are used to plot an O-C diagram in order to determine the ephemeris and evaluate evidence for period change. We wish to thank the Brigham Young University College of Physical and Mathematical Sciences as well as the Department of Physics and Astronomy for their continued support of the research activities at the West Mountain Observatory.

  12. 13-Color Photometry of 16 Variable Be-Stars - Part One - Photometry

    NASA Astrophysics Data System (ADS)

    Alvarez, M.; Schuster, W. J.

    1982-07-01

    We present thirteen color photometry of 16 variable Be stars observed at the Observatorio Astronomico Nacional in San Pedro Martir in Baja California, Our data cover the years 1977 to 1979, and we include earlier measurements of Johnson and Mitchell from 1965 to 1968 that have been corrected in order to have a homogeneous set of data.

  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. VizieR Online Data Catalog: Westerlund 2 UBVIc photometry (Hur+, 2015)

    NASA Astrophysics Data System (ADS)

    Hur, H.; Park, B.-G.; Sung, H.; Bessell, M. S.; Lim, B.; Chun, M.-Y.; Sohn, S. T.

    2015-06-01

    Deep UBVIC observations were obtained on 2009 March 28 and 2 the 8kx8k Mosaic II CCD camera (0.268arcsec/pix) of the 4m Blanco telescope at Cerro Tololo Inter-American Observatory (CTIO). We used the SDSS u filter for U-band photometry and the Harris BVI filter set for BVIC photometry. The exposure times were 7 and 150s in I, 10 and 300s in V, 20 and 300s in B, and 100 and 1200 s in u. The average seeing was ~0.9-arcsec. For the photometry of bright stars and for the standardization of U-B, we performed additional observations with the Y4KCam CCD camera and UBVIC filter set of the 1m telescope at CTIO on 2011 March 5. The exposure times were 5 and 180s in I, 5 and 180s in V, 10 and 300s in B, and 30 and 600s in U. (2 data files).

  15. Visual optics and ecomorphology of the growing shark eye: a comparison between deep and shallow water species.

    PubMed

    Litherland, Lenore; Collin, Shaun P; Fritsches, Kerstin A

    2009-11-01

    Elasmobranch fishes utilise their vision as an important source of sensory information, and a range of visual adaptations have been shown to reflect the ecological diversity of this vertebrate group. This study investigates the hypotheses that visual optics can predict differences in habitat and behaviour and that visual optics change with ontogenetic growth of the eye to maintain optical performance. The study examines eye structure, pupillary movement, transmission properties of the ocular media, focal properties of the lens, tapetum structure and variations in optical performance with ontogenetic growth in two elasmobranch species: the carcharhinid sandbar shark, Carcharhinus plumbeus, inhabiting nearshore coastal waters, and the squalid shortspine spurdog, Squalus mitsukurii, inhabiting deeper waters of the continental shelf and slope. The optical properties appear to be well tuned for the visual needs of each species. Eyes continue to grow throughout life, resulting in an ontogenetic shift in the focal ratio of the eye. The eyes of C. plumbeus are optimised for vision under variable light conditions, which change during development as the animal probes new light environments in its search for food and mates. By contrast, the eyes of S. mitsukurii are specifically adapted to enhance retinal illumination within a dim light environment, and the detection of bioluminescent prey may be optimised with the use of lenticular short-wavelength-absorbing filters. Our findings suggest that the light environment strongly influences optical features in this class of vertebrates and that optical properties of the eye may be useful predictors of habitat and behaviour for lesser-known species of this vertebrate group. PMID:19837900

  16. Near-infrared photometry of carbon stars

    NASA Astrophysics Data System (ADS)

    Whitelock, Patricia A.; Feast, Michael W.; Marang, Freddy; Groenewegen, M. A. T.

    2006-06-01

    Near-infrared, JHKL, photometry of 239 Galactic C-rich variable stars is presented and discussed. From these and published data, the stars were classified as Mira or non-Mira variables, and amplitudes and pulsation periods, ranging from 222 to 948 d for the Miras, were determined for most of them. A comparison of the colour and period relations with those of similar stars in the Large Magellanic Cloud indicates minor differences, which may be the consequence of sample selection effects. Apparent bolometric magnitudes were determined by combining the mean JHKL fluxes with mid-infrared photometry from IRAS and MSX. Then, using the Mira period luminosity relation to set the absolute magnitudes, distances were determined - to greater accuracy than has hitherto been possible for this type of star. Bolometric corrections to the K magnitude were calculated and prescriptions derived for calculating these from various colours. Mass-loss rates were also calculated and compared to values in the literature. Approximately one-third of the C-rich Miras and an unknown fraction of the non-Miras exhibit apparently random obscuration events that are reminiscent of the phenomena exhibited by the hydrogen-deficient R Coronae Borealis stars. The underlying cause of this is unclear, but it may be that mass loss, and consequently dust formation, is very easily triggered from these very extended atmospheres. Based on observations made at the South African Astronomical Observatory. E-mail: paw@saao.ac.za

  17. Photometry Of Pluto At Low Galactic Latitudes

    NASA Astrophysics Data System (ADS)

    George, Erin; Buie, M.; Bagenal, F.

    2012-10-01

    Our research is part of an ongoing project to continue the long-term photometric monitoring of Pluto in hopes to constrain volatile migration on the surface. As Pluto passes near the center of the galaxy, the fields are too crowded with stars for normal aperture photometry. We approached this problem by using Optimal Image Subtraction (OIS). We took images, both containing and not containing Pluto, using the 0.8m robotic telescope at Lowell Observatory, the 1m robotic telescope at New Mexico State University, and the Faulkes 2m robotic telescope at Siding Spring, part of Las Cumbres Observatory. We are presently gathering data, but our main focus was the data from 2010. We began by taking images of the star fields at the galactic center without Pluto to build catalogs of standard stars. These catalogs were applied to the Pluto images in order to make interpolated images and to cross check our results. We extracted the photometry of Pluto from differenced images where the background stars were subtracted, and we then applied the transformation equation to solve for Pluto’s standard magnitude. We will present the details of our data processing methodology, as well as the 2010 Pluto B, V, and B-V light curves in comparison to those from previous years. This work was supported by NASA Planetary Astronomy Grant NNX09AB43G.

  18. 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.

  19. 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.

  20. 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.

  1. T-PHOT: A new code for PSF-matched, prior-based, multiwavelength extragalactic deconfusion photometry

    NASA Astrophysics Data System (ADS)

    Merlin, E.; Fontana, A.; Ferguson, H. C.; Dunlop, J. S.; Elbaz, D.; Bourne, N.; Bruce, V. A.; Buitrago, F.; Castellano, M.; Schreiber, C.; Grazian, A.; McLure, R. J.; Okumura, K.; Shu, X.; Wang, T.; Amorín, R.; Boutsia, K.; Cappelluti, N.; Comastri, A.; Derriere, S.; Faber, S. M.; Santini, P.

    2015-10-01

    Context. The advent of deep multiwavelength extragalactic surveys has led to the necessity for advanced and fast methods for photometric analysis. In fact, codes which allow analyses of the same regions of the sky observed at different wavelengths and resolutions are becoming essential to thoroughly exploit current and future data. In this context, a key issue is the confusion (i.e. blending) of sources in low-resolution images. Aims: We present t-phot, a publicly available software package developed within the astrodeep project. t-phot is aimed at extracting accurate photometry from low-resolution images, where the blending of sources can be a serious problem for the accurate and unbiased measurement of fluxes and colours. Methods: t-phot can be considered as the next generation to tfit, providing significant improvements over and above it and other similar codes (e.g. convphot). t-phot gathers data from a high-resolution image of a region of the sky, and uses this information (source positions and morphologies) to obtain priors for the photometric analysis of the lower resolution image of the same field. t-phot can handle different types of datasets as input priors, namely i) a list of objects that will be used to obtain cutouts from the real high-resolution image; ii) a set of analytical models (as .fits stamps); iii) a list of unresolved, point-like sources, useful for example for far-infrared (FIR) wavelength domains. Results: By means of simulations and analysis of real datasets, we show that t-phot yields accurate estimations of fluxes within the intrinsic uncertainties of the method, when systematic errors are taken into account (which can be done thanks to a flagging code given in the output). t-phot is many times faster than similar codes like tfit and convphot (up to hundreds, depending on the problem and the method adopted), whilst at the same time being more robust and more versatile. This makes it an excellent choice for the analysis of large datasets

  2. Ten Recent Enhancements To Aperture Photometry Tool

    NASA Astrophysics Data System (ADS)

    Laher, Russ; Rebull, L. M.; Gorjian, V.

    2013-01-01

    Aperture Photometry Tool is free, multi-platform, easy-to-install software for astronomical research, as well as for learning, visualizing, and refining aperture-photometry analyses. This mature software has been under development for five years, and is a silent workhorse of the NASA/IPAC Teacher Archive Research Program. Software version 2.1.5 is described by Laher et al., Publications of the Astronomical Society of the Pacific, Vol. 124, No. 917, pp. 737-763, (July 2012). Four software upgrades have been released since the publication, which include new capabilities, increased speed, more user-friendliness, and some minor bug fixes. Visit www.aperturephotometry.org to download the latest version. The enhancements are as follows: 1) Added new Tools menu option to write selected primary-image data to a comma-separated-value file (for importing into Excel); 2) Added a new display of the color-table levels on a separate panel; 3) Added a new tool to measure the angular separation between positions on the thumbnail image, via mouse-cursor drag and release; 4) Added a new tool to overlay an aperture at user-specified coordinates (in addition to aperture overlay via mouse click); 5) Speeded up the source-list tool with optional multithreading in its automatic mode (allowed thread number is user-specifiable); 6) Added a new “Number” column to the output aperture-photometry-table file in order to track the input source order (multithreading reorders the output); 7) Upgraded the source-list tool to accept input source lists containing positions in sexagesimal equatorial coordinates (in addition to decimal degrees, or, alternatively, pixel coordinates); 8) Added a new decimal/sexagesimal converter; 9) Upgraded the source-list creation tool to compute the detection threshold using robust estimates of the local background and local data dispersion, where the user can select the grid and window sizes for these local calculations; and 10) Modified the batch mode to

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. UBVRI photometry of W Ursae Majoris

    NASA Astrophysics Data System (ADS)

    Linnell, A. P.

    1985-03-01

    High speed UBVRI photometry of W Ursae Majoris produced 15,930 observations covering one complete cycle on 1984 March 5-6. For this epoch, total phase of primary minimum is flat in all spectral bands, while secondary minimum shows a substantial tilt during annual phases. The tilt correlates with a detectable O'Connell effect, indicates a transverse temperature gradient across the projected disk of the primary component, and is qualitatively consistent with a starspot origin for both effects. Gross characteristics of the color curves are consistent with those expected from the wavelength dependence of limb darkening. The observed greater color change at primary minimum as contrasted with secondary must have a different origin. There is qualitative consistency with a Rucinski hot secondary model. Whether consistency can also be achieved with a Mullan starspot model, or whether decisive discrimination between alterative physical models can be demonstrated must await detailed light synthesis simulation.

  10. Selecting M-giants with WISE photometry

    NASA Astrophysics Data System (ADS)

    Li, Jing

    2015-08-01

    We use M-giants, M-dwarfs and QSOs identified by LAMOST to assess how well WISE & 2MASS colour-cuts can separate these populations through photometry. We find that the WISE bands are very efficient to separate M-giants from M-dwarfs, especially for the early-type stars. We derive a new photometric relation to estimate [Fe/H] for M-giants. We show that previous photometric distance relations may be biased and devise a new empirical distance relation. We detect M-giants in the Sagittarius stream from the ALLWISE Source Archive. Our detection shows good agreement with the bright stream, although the leading tail appears to be misaligned by a couple of degrees. We have measured the metallicity distribution at four locations along the stream, finding a clear metallicity offset between the leading and trailing tails.

  11. 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.

  12. Photometry Transforms Generation with PTGP (Abstract)

    NASA Astrophysics Data System (ADS)

    Myers, G.; Menzies, K.; Silvis, G.; Harris, B.

    2015-06-01

    (Abstract only) Historically the development of photometry transformation coefficients required extensive manual effort and the use of large spreadsheets. A new release—version 5.0—of the Photometry Transformations Generation Program (PTGP) achieves the goal of generating transformation coefficients without the use of spreadsheets—saving considerable time and ensuring data accuracy. PTGP version 5.0 works directly with VSP to retrieve the most recent standard star reference magnitudes (currently for M67 and NGC7790). It then processes instrument magnitude file(s) downloaded from vphot or exported from AIP4WIN or MAXIM. Either AUID or “Boulder” star identifications can be used for AIP4WIN and MAXIM. When using VPHOT data or “Boulder” star identifications, PTGP determines the AUID names for each of the reference standard stars. All standard transforms are calculated. Plots of each transform's data can be reviewed, and individual star observations added/deleted. Transform sets can be saved for further use. Transform sets can be compared and selected sets averaged. The averaged sets can be exported in a file format compatible with the AAVSO TA tool. The presentation will provide a brief overview and demonstration of the tool. It will also discuss the implications of using PYTHON for the development—both benefits and potential problems. The program runs on both PCs and Macs. A subsequent presentation will discuss the use of VPHOT and PTGP to generate transforms and the testing of the impacts of varying key VPHOT and PTGP parameters.

  13. VizieR Online Data Catalog: ZYJHK photometry in Pleiades (Lodieu+, 2007)

    NASA Astrophysics Data System (ADS)

    Lodieu, N.; Dobbie, P. D.; Deacon, N. R.; Hodgkin, S. T.; Hambly, N. C.; Jameson, R. F.

    2007-11-01

    We present the results of a deep wide-field near-infrared survey of 12deg2 of the Pleiades conducted as part of the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Galactic Cluster Survey (GCS). We have extracted over 340 high-probability proper motion (PM) members down to 0.03M{sun} using a combination of UKIDSS photometry and PM measurements obtained by cross-correlating the GCS with data from the Two Micron All Sky Survey, the Isaac Newton Telescope and the Canada-France-Hawaii Telescope. Additionally, we have unearthed 73 new candidate brown dwarf (BD) members on the basis of five-band UKIDSS photometry alone. We have identified 23 substellar multiple system candidates out of 63 candidate BDs from the (Y-K, Y) and (J-K, J) colour-magnitude diagrams, yielding a binary frequency of 2844 per cent in the 0.075-0.030M{sun} mass range. (7 data files).

  14. 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.

  15. High-speed ultraviolet photometry of HD 60435

    NASA Technical Reports Server (NTRS)

    Taylor, M.; Nelson, M. J.; Bless, R. C.; Dolan, J. F.; Elliot, J. L.; Percival, J. W.; Robinson, E. L.; Van Citters, G. W.

    1993-01-01

    We present the first high-speed ultraviolet photometry of an oscillating Ap star, HD 60435. After removing known orbital effects related to the Hubble Space Telescope, we confirm the presence of a strong pulsation period at a frequency of 123.70 cycles per day. In addition, we find significant amplitude modulation of this frequency that we suggest could be the result of beating of multiple periodicities. In this context, we suggest evidence for the presence of four additional frequencies at nu = 120.56, 126.55, 149.49, and 221.03 cycles per day. Three of these frequencies correspond well to frequencies detected in optical observations of HD 60435. The fourth, at 149.49 cycles per day, if real, is a potentially new pulsation mode that has not been detected in ground-based observations of this star. The amplitude of the 123 cycles per day pulsation is significantly larger in the ultraviolet than it is in the blue.

  16. 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.

  17. 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.

  18. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour.

    PubMed

    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

  19. 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

  20. 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).

  1. The TAOS Project: High-Speed Crowded Field Aperture Photometry

    NASA Astrophysics Data System (ADS)

    Zhang, Z.-W.; Kim, D.-W.; Wang, J.-H.; Lehner, M. J.; Chen, W. P.; Byun, Y.-I.; Alcock, C.; Axelrod, T.; Bianco, F. B.; Coehlo, N. K.; Cook, K. H.; Dave, R.; de Pater, I.; Giammarco, J.; King, S.-K.; Lee, T.; Lin, H.-C.; Marshall, S. L.; Porrata, R.; Protopapas, P.; Rice, J. A.; Schwamb, M. E.; Wang, S.-Y.; Wen, C.-Y.

    2009-12-01

    We have devised an aperture photometry pipeline for data reduction of image data from the Taiwanese-American Occultation Survey (TAOS). The photometry pipeline has high computational performance, and is capable of real-time photometric reduction of images containing up to 1000 stars, within the sampling rate of 5 Hz. The pipeline is optimized for both speed and signal-to-noise performance, and in the latter category it performs nearly as well as DAOPHOT. This paper provides a detailed description of the TAOS aperture photometry pipeline.

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Wavelet analysis of fast photometry on Cygnus X-1 with the AstraLux camera

    SciTech Connect

    Luque-Escamilla, P. L.; Marti, J.; Combi, Jorge A.; Arjonilla, Alvaro Munoz; Sanchez-Sutil, J. R.

    2008-10-08

    We present sub-second fast photometry for the high mass X-ray binary Cygnus X-1. We try to observe variability due to instabilities in the accretion process at optical wavelengths. The observations were carried out using the high speed AstraLux camera at the Calar Alto 2.2 m telescope, Spain, in November 2006 and August 2007. We report that the Cygnus X-1 system light curve sampled every 30 milli-second did not display strong enough evidence of any periodic component related to the source.

  8. Comparison of Metallicities Adopted for the Synthetic UBV Photometry with Those Evaluated by Means of RGU Photometry

    NASA Astrophysics Data System (ADS)

    Karaali, S.; Güngör, S.; Karatas, Y.

    1998-04-01

    Comparison of metallicities adopted for the synthetic UBV photometry with those evaluated by means of RGU photometry for 92 stars is presented. The agreement only for zero metallicity. The discrepancy increases to low metallicities which cover Intermediate population and Population II main-sequence star. U-G and G-R colour indices are transformed from UBV synthetic data and do not include any observational error. Therefore, the disagreement may orginate from a systematic error in the metallicity calibration of relatively metal-poor stars in RGU photometry.

  9. 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.

  10. 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

  11. 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.

  12. Deep optical spectroscopy of extended Lyα emission around three radio-quiet z = 4.5 quasars

    NASA Astrophysics Data System (ADS)

    Courbin, F.; North, P.; Eigenbrod, A.; Chelouche, D.

    2008-09-01

    We report the first results of a spectroscopic search for Lyα envelopes around three z˜4.5 radio-quiet quasars. Our observational strategy adopts the FORS2 spectrograph mounted to the UT1 of the Very Large Telescope (VLT) in the multi-slit mode. This allows us to observe simultaneously the quasars and several PSF stars. The spectra of the latter are used to remove the point-like quasar from the data, and to unveil the faint underlying Lyα envelopes associated with the quasars to unprecedented depth. We clearly detect an envelope around two of the three quasars. The sizes of these envelopes are 10´´ and 13´´ (i.e. 67 kpc and 87 kpc). This is 5 to 10 times larger than predicted by the models of Haiman & Rees (2001, ApJ, 556, 87) and up to 100 times fainter. Our observations are in more robust agreement with models involving a clumpy envelope such as Alam & Miralda-Escudé (2002, ApJ, 568, 576) or Chelouche et al. (2007, ApJ, submitted). We find that the brighter quasars also have the brighter envelopes but that the extent of the envelopes does not depend on the quasar luminosity. Although our results are based on only two objects with a detected Lyα envelope, the quality of the spatial deblending of the spectra lends considerable for hope to estimating the luminosity function and surface brightness profiles of high redshift Lyα envelopes down to F˜ 2-3 × 10-21 erg s-1 cm-2 Å-1. We conclude that the most efficient strategy for studying high redshift Lyα quasar envelopes is to acquire both narrow-band images and deep slit-spectra. Based on observations made with the FORS2 multi-object spectrograph mounted on the Antu VLT telescope at ESO-Paranal Observatory (programme 079.B-0132B; PI: P. North).

  13. Photometry, Astrometry, and Young Discoveries of Ultracool Dwarfs in the Pan-STARRS1 3π Survey

    NASA Astrophysics Data System (ADS)

    Best, William M. J.; Magnier, Eugene A.; Liu, Michael C.

    2016-01-01

    The Pan-STARRS1 3π Survey (PS1) has observed three-quarters of the sky in five optical bands (grizy) over multiple epochs spanning four years, creating an unprecedented resource for discovering and characterizing ultracool dwarfs. We present an analysis of the PS1 photometry and astrometry of all known L and T dwarfs. We will also highlight some especially interesting and serendipitous discoveries of young ultracool dwarfs.

  14. 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.

  15. 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.

  16. 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.

  17. BVRI CCD photometry of Omega Centauri

    NASA Astrophysics Data System (ADS)

    Alcaino, Gonzalo; Liller, William

    1987-12-01

    The authors present the first CCD, BVRI main-sequence photometry for ω Cen, matched to the new BVRI isochrones of VandenBerg and Bell (1985). Their main conclusions are: (1) The main-sequence turnoffs as seen in the several colors are found to be at VTO = 18.3±0.15; the MSTO color indexes are at: B-V = 0.55±0.03, V-I = 0.73±0.03, and B-I = 1.28±0.03. (2) The magnitude difference between the main-sequence turnoff and the horizontal branch is ΔMV = 3.80±0.15, as derived from the color-magnitude diagrams. (3) The authors deduce a consistent age for ω Cen in all three color-magnitude diagrams of 17±1.5 Gyr. (4) The large scatter among the main-sequence stars demonstrates that the chemical inhomogeneity of about |Fe/H| = ≡1 dex persists as well in the unevolved stars, hence suggesting the composition to be primordial.

  18. The HST Milky Way Stellar Photometry Archive

    NASA Astrophysics Data System (ADS)

    Radburn-Smith, David

    2012-10-01

    The Hubble Legacy Archive has invested a significant effort into automatically generating photometry for point sources in all HST observations regardless of the target. We estimate that this archive contains up to 800,000 Milky Way {MW} stars, distributed across the whole sky, complete to some three magnitudes fainter than SDSS. Approximately half of these stars have color information, which is required for stellar population analysis. This considerable archive is thus in need of collation, analysis, and publication.Here we propose to compile such a catalog for public access and to use it for two science goals: 1} A test of existing MW stellar models, where we will in particular constrain the fainter and more distant stellar populations; and 2} Probe the shape and structure of the MW stellar halo with a deeper star catalog than is currently available. These science cases will be used to fully define the catalog, in particular by assessing the different populations present in the observations, and by assessing the level of noise from contaminants and the completeness of the survey

  19. 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.

  20. 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.

  1. Time series photometry and starspot properties

    NASA Astrophysics Data System (ADS)

    Oláh, Katalin

    2011-08-01

    Systematic efforts of monitoring starspots from the middle of the XXth century, and the results obtained from the datasets, are summarized with special focus on the observations made by automated telescopes. Multicolour photometry shows correlations between colour indices and brightness, indicating spotted regions with different average temperatures originating from spots and faculae. Long-term monitoring of spotted stars reveals variability on different timescales. On the rotational timescale new spot appearances and starspot proper motions are followed from continuous changes of light curves during subsequent rotations. Sudden interchange of the more and less active hemispheres on the stellar surfaces is the so called flip-flop phenomenon. The existence and strength of the differential rotation is seen from the rotational signals of spots being at different stellar latitudes. Long datasets, with only short, annual interruptions, shed light on the nature of stellar activity cycles and multiple cycles. The systematic and/or random changes of the spot cycle lengths are discovered and described using various time-frequency analysis tools. Positions and sizes of spotted regions on stellar surfaces are calculated from photometric data by various softwares. From spot positions derived for decades, active longitudes on the stellar surfaces are found, which, in case of synchronized eclipsing binaries can be well positioned in the orbital frame, with respect to, and affected by, the companion stars.

  2. BVRI photometry of DQ Herculis in 2014

    NASA Astrophysics Data System (ADS)

    Dmitrienko, E. S.; Ibragimov, M. A.; Savanov, I. S.; Satovskii, B. L.; Egamberdiev, Sh. A.; Burkhanov, O. A.

    2015-09-01

    The results of BV RI photometry of the nova DQ Her 1934 performed at the Maidanak Observatory of the Astronomical Institute of the Uzbek Academy of Sciences in October 2014 are presented. The system's brightness, the out-of-eclipse color indices, and the shape of the minima in the BV RI light curves, which are due to eclipses of the white dwarf with its accreting disk-like envelope by the red dwarf, correspond to one of the lowest activity levels observed during the system's deepest relaxation after a nova outburst. The orbital-phase variations of the color indices indicate the presence of a considerably non-uniform brightness distribution for light coming from the disk-like envelope and other gaseous structures of DQ Her, which are observed at orbital phases of 0.85-1.15. The results can be qualitatively interpreted in a picture in which the gas flow structure is formed during mass exchange in an intermediate polar. The behavior found for the color indices could be due, for example, to the visibility in this phase interval of the passage of regions of shocks (tidal shocks, a hot line, and/or a detached shock) through the line of sight.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Correlation of plasma characteristics to etch rate and via sidewall angle in a deep reactive ion etch system using Langmuir probe and optical emission spectroscopy

    SciTech Connect

    Koirala, S. P.; Awaah, I.; Burkett, S. L.; Gordon, M. H.

    2011-01-15

    A Langmuir probe and optical emission spectroscopy were used in a deep reactive ion etch system to correlate plasma parameters (atomic fluorine and argon emission, electron density, ion density, and electron average energy) with the etch rate and via sidewall angle. All data were obtained for coil powers ranging from 200 to 800 W, platen powers ranging from 7 to 16 W, and pressure ranging from 3.8 to 62 mTorr with constant SF{sub 6} and Ar flow rates of 112 and 18 SCCM (SCCM denotes cubic centimeter per minute at STP), respectively. Results indicate that there is a correlation with etch rate for all plasma parameters except for argon emission. For argon emission, the etch rate exhibits a double-valued relation where the etch rate can either increase or decrease with increasing argon emission intensity due to changes in pressure which affect the energy coupling efficiency. As expected, the etch rate increases for measured increases in fluorine emission, electron density, and ion density. The etch rate, however, decreases with increasing average electron energy due to collision processes. In contrast, no correlation is observed between any of the measured plasma parameters with sidewall angle. The last result is consistent with the idea that sidewall angle is primarily controlled by the passivation cycle as opposed to the etching cycle, where all the authors' data were obtained.

  9. 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.

  10. Quasar probabilities and redshifts from WISE mid-IR through GALEX UV photometry

    NASA Astrophysics Data System (ADS)

    DiPompeo, M. A.; Bovy, J.; Myers, A. D.; Lang, D.

    2015-09-01

    Extreme deconvolution (XD) of broad-band photometric data can both separate stars from quasars and generate probability density functions for quasar redshifts, while incorporating flux uncertainties and missing data. Mid-infrared photometric colours are now widely used to identify hot dust intrinsic to quasars, and the release of all-sky WISE data has led to a dramatic increase in the number of IR-selected quasars. Using forced photometry on public WISE data at the locations of Sloan Digital Sky Survey (SDSS) point sources, we incorporate this all-sky data into the training of the XDQSOz models originally developed to select quasars from optical photometry. The combination of WISE and SDSS information is far more powerful than SDSS alone, particularly at z > 2. The use of SDSS+WISE photometry is comparable to the use of SDSS+ultraviolet+near-IR data. We release a new public catalogue of 5537 436 (total; 3874 639 weighted by probability) potential quasars with probability PQSO > 0.2. The catalogue includes redshift probabilities for all objects. We also release an updated version of the publicly available set of codes to calculate quasar and redshift probabilities for various combinations of data. Finally, we demonstrate that this method of selecting quasars using WISE data is both more complete and efficient than simple WISE colour-cuts, especially at high redshift. Our fits verify that above z ˜ 3 WISE colours become bluer than the standard cuts applied to select quasars. Currently, the analysis is limited to quasars with optical counterparts, and thus cannot be used to find highly obscured quasars that WISE colour-cuts identify in significant numbers.

  11. 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.

  12. 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).

  13. The Subaru-XMM-Newton Deep Survey (SXDS). VIII. Multi-wavelength identification, optical/NIR spectroscopic properties, and photometric redshifts of X-ray sources†

    NASA Astrophysics Data System (ADS)

    Akiyama, Masayuki; Ueda, Yoshihiro; Watson, Mike G.; Furusawa, Hisanori; Takata, Tadafumi; Simpson, Chris; Morokuma, Tomoki; Yamada, Toru; Ohta, Kouji; Iwamuro, Fumihide; Yabe, Kiyoto; Tamura, Naoyuki; Moritani, Yuuki; Takato, Naruhisa; Kimura, Masahiko; Maihara, Toshinori; Dalton, Gavin; Lewis, Ian; Lee, Hanshin; Curtis-Lake, Emma; Macaulay, Edward; Clarke, Frazer; Silverman, John D.; Croom, Scott; Ouchi, Masami; Hanami, Hitoshi; Díaz Tello, Jorge; Yoshikawa, Tomohiro; Fujishiro, Naofumi; Sekiguchi, Kazuhiro

    2015-10-01

    We report on the multi-wavelength identification of the X-ray sources found in the Subaru-XMM-Newton Deep Survey (SXDS) using deep imaging data covering the wavelength range between the far-UV and mid-IR (MIR). We select a primary counterpart of each X-ray source by applying the likelihood ratio method to R-band, 3.6 μm, near-UV, and 24 μm source catalogs as well as matching catalogs of active galactic nucleus (AGN) candidates selected in 1.4 GHz radio and i '-band variability surveys. Once candidates for Galactic stars, ultra-luminous X-ray sources in a nearby galaxy, and clusters of galaxies are removed there are 896 AGN candidates in the sample. We conduct spectroscopic observations of the primary counterparts with multi-object spectrographs in the optical and NIR; 65% of the X-ray AGN candidates are spectroscopically identified. For the remaining X-ray AGN candidates, we evaluate their photometric redshift with photometric data in 15 bands. Utilizing the multi-wavelength photometric data of the large sample of X-ray-selected AGNs, we evaluate the stellar masses, M*, of the host galaxies of the narrow-line AGNs. The distribution of the stellar mass is remarkably constant from z = 0.1 to 4.0. The relation between M* and 2-10 keV luminosity can be explained with strong cosmological evolution of the relationship between the black hole mass and M*. We also evaluate the scatter of the UV-MIR spectral energy distribution (SED) of the X-ray AGNs as a function of X-ray luminosity and absorption by the nucleus. The scatter is compared with galaxies which have redshift and stellar mass distribution matched with the X-ray AGN. The UV-NIR (near-IR) SEDs of obscured X-ray AGNs are similar to those of the galaxies in the matched sample. In the NIR-MIR range, the median SEDs of X-ray AGNs are redder, but the scatter of the SEDs of the X-ray AGN broadly overlaps that of the galaxies in the matched sample.

  14. 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

  15. Revised Filter Profiles and Zero Points for Broadband Photometry

    NASA Astrophysics Data System (ADS)

    Mann, Andrew W.; von Braun, Kaspar

    2015-02-01

    Estimating accurate bolometric fluxes for stars requires reliable photometry to absolutely flux calibrate the spectra. This is a significant problem for studies of very bright stars, which are generally saturated in modern photometric surveys. Instead we must rely on photometry with less precise calibration. We utilize precisely flux-calibrated spectra to derive improved filter bandpasses and zero points for the most common sources of photometry for bright stars. In total, we test 39 different filters in the General Catalog of Photometric Data as well as those from Tycho-2 and Hipparcos. We show that utilizing inaccurate filter profiles from the literature can create significant color terms resulting in fluxes that deviate by gsim10% from actual values. To remedy this we employ an empirical approach; we iteratively adjust the literature filter profile and zero point, convolve it with catalog spectra, and compare to the corresponding flux from the photometry. We adopt the passband values that produce the best agreement between photometry and spectroscopy and are independent of stellar color. We find that while most zero points change by < 5%, a few systems change by 10-15%. Our final profiles and zero points are similar to recent estimates from the literature. Based on determinations of systematic errors in our selected spectroscopic libraries, we estimate that most of our improved zero points are accurate to 0.5-1%.

  16. Correlating Total Visual Magnitude Estimates and CCD Photometry for Comets

    NASA Astrophysics Data System (ADS)

    Kidger, Mark Richard

    2015-08-01

    A key facet of understanding the activity of comets is coverage of their light curve. For some comets such as 2P/Encke there is good light curve coverage from visual observers extending back over many returns over more than 2 centuries. However, in recent years, CCD photometry by amateur astronomers has become the dominant data source and the number of total visual magnitude estimates has reduced sharply, making comparison of recent and historical photometric data for comets increasingly difficult. The relationship between total visual magnitude estimates - dominated by the emission from the Swan bands of C2 - and CCD aperture photometry - dominated by the dust continuum - has been far from clear.This paper compares CCD aperture photometry and total visual magnitude for several recent well-observed bright comets, including C/2014 Q2 (Lovejoy), C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS) using a consistent and homogeneous database of observations from (mainly) Spanish observers. For comets with a 1/r radial coma profile, good agreement is found between CCD aperture photometry and total visual magnitude estimates for a CCD aperture corresponding to a physical coma diameter of ≈105km.The relationship between the coma radial brightness slope and the equivalent physical aperture for CCD photometry to obtain agreement with total visual magnitude estimates is investigated.

  17. CCD photometry of the BL Lacertae object 1400+162 and the associated group of galaxies

    NASA Technical Reports Server (NTRS)

    Weistrop, D.; Reitsema, H. J.; Smith, B. A.; Shaffer, D. B.

    1983-01-01

    Surface photometry of the BL Lacertae object 1400+162 and an apparently associated group of galaxies has been obtained using a CCD camera. Observations were made in V, broad bandpasses centered on 0.75 micron and 1.0 micron and with no filter. The colors of all but two of the galaxies suggest they are ellipticals, with the colors of the remaining two considerably bluer. Analysis using a method described by Schechter and Press (1976) suggests the group is a small one. The group may be similar to the one associated with the quasar 3C 273. The spectral index of the BL Lac object is 1.49 + or 0.21. This value allows, but does not require, the presence of an underlying elliptical galaxy. The radio-optical and optical-X-ray indices for 1400+162 are similar to values found for quasars.

  18. 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.

  19. PGC 0029664-1188757: PHOTOMETRY OF TWO INTERACTING GALAXIES AND THEIR DEBRIS

    SciTech Connect

    Lira, Elias; Galaz, Gaspar E-mail: ggalaz@astro.puc.c

    2010-12-15

    We present basic data on the stellar populations of the interacting galaxies PGC0029664 and PGC1188757, and their debris. Comparing B, V, R, and I deep photometry and colors obtained with the Magellan telescope with models of galaxy evolution, we estimate ages and metallicities of the stellar populations in both galaxies, as well as in those resolved regions resulting apparently from the interaction itself, namely, a bridge of material between both galaxies and the many small features observed in the spiral arms. Results suggest that blue and bright spots observed in the bridge are composed of recently formed stars, since they have similar blue colors to those observed in three regions embedded in the spiral arms of PGC0029664, very likely regions of recent star formation.

  20. Infrared photometry of the 1982-4 eclipse of Epsilon Aurigae

    NASA Technical Reports Server (NTRS)

    Backman, D. E.

    1985-01-01

    The infrared photometry of epsilon Aur performed prior to and during the ingress phase of the recent eclipse allowed the first solid determination of the temperature of the secondary object. The eclipse depth was significantly less at lambda 5 micrometers than in the near-infrared. This is explained by a model of the secondary as an opaque and very cool object with a temperature of approx. 500 K. During eclipse, the secondary blocks approximately 45% of the near infrared radiation from the primary star. At the same time, the radiation from the secondary remains completely unobscured, resulting in a shallower light curve at longer wavelengths. This phenomenon is well known in the study of eclipsing binary stars; if the two stars have different colors, then the net color of the system changes during eclipse. In the case of epsilon Aur, the eclipsing object has a color deep in the infrared, so the effect is only noticeable there.

  1. 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

  2. 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.

  3. Five nights of intensive R- and V-band photometry of QSO 0957+561A,B

    NASA Astrophysics Data System (ADS)

    Ovaldsen, J. E.; Teuber, J.; Stabell, R.; Evans, A. K. D.

    2003-11-01

    We present R- and V-band photometry of the gravitational lens system QSO 0957+561 from five nights (one in 2000 January and four in 2001 March, corresponding to the approximate time delay for the system) of uninterrupted monitoring at the Nordic Optical Telescope. In the photometry scheme we have stressed careful magnitude calibration as well as corrections for the lens galaxy contamination and the crosstalk between the twin (A and B) quasar images. The resulting, very densely sampled, light curves are quite stable, in conflict with earlier claims derived from the same data material. We estimate high-precision timelag-corrected B/A flux ratios in both colour bands, as well as V-R colour indices for A and B, and discuss the short time-scale variability of the system.

  4. 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.

  5. CCD Photometry of Bright Stars Using Objective Wire Mesh

    NASA Astrophysics Data System (ADS)

    Kamiński, Krzysztof; Schwarzenberg-Czerny, Aleksander; Zgórz, Marika

    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.

  6. Deep-Space Optical Terminals

    NASA Technical Reports Server (NTRS)

    Hemmati, H.; Farr, W. H.; Biswas, A.; Birnbaum, K. M.; Roberts, W. T.; Quirk, K.; Townes, S.

    2011-01-01

    We eport on engineering trades that led to the conceptual design of a laser communications terminal for spacecraft probing Mars. The flight terminal, the ground receiver and the ground transmitter subsystems are described. The flight terminal point design has 0.25 Gb/s downlink data-rate capability from the Mars close distance (0.42 AU). Capability for uplink data-rate of 0.3 Mb/s and ranging with 30 cm precision are also addressed.

  7. A Study of Dust Cloud Parameters by Vilnius Photometry

    NASA Astrophysics Data System (ADS)

    Smriglio, F.; Dasgupta, A. K.; Boyle, R. P.

    Three-dimensional classification of stars based on their seven-color CCD photometry in the Vilnius system has been succesfully applied to study the small scale structure of interstellar dust clouds. In the present paper the statistical equations of Munch are modified and applied to stars located beyond the galactic absorbing layer. This particular use of Munch's statistics and the properties of CCD photometry in the Vilnius system offer a better possibility of probing the small scale structure of interstellar medium outside of the solar vicinity. This new technique and the first results are discussed.

  8. The Structure of Galaxies I: Surface Photometry Techniques

    NASA Astrophysics Data System (ADS)

    Schombert, J.; Smith, A. K.

    2012-04-01

    This project uses the 2MASS all-sky image database to study the structure of galaxies over a range of luminosities, sizes and morphological types. This first paper in this series will outline the techniques, reliability and data products to our surface photometry program. Our program will analyze all acceptable galaxies (meeting our criteria for isolation from companions and bright stars) from the Revised Shapley-Ames and Uppsala galaxy catalogs. Resulting photometry and surface brightness profiles are released using a transparent scheme of data storage which includes not only all the processed data but knowledge of the processing steps and calibrating parameters.

  9. The spotted contact binary SS ARIETIS - Spectroscopy and infrared photometry

    NASA Astrophysics Data System (ADS)

    Rainger, P. P.; Bell, S. A.; Hilditch, R. W.

    1992-02-01

    The first infrared photometry for the W-UMa system SS Ari is presented. An analysis based on medium-resolution spectroscopy presented here shows that SS Ari is a W-type system with a mass ratio of 0.33. It seems certain that the asymmetry in the published light curves and those obtained for this study can be explained by the effect of spots on one or possibly both components of the system. The precise location, size and temperature of these spots require the use of Doppler Imaging techniques in conjunction with high-quality multiband photometry.

  10. A method for determining stellar parameters from multicolor photometry

    NASA Astrophysics Data System (ADS)

    Sichevskij, S. G.

    2012-09-01

    Amethod for determining the most probable spectral types, color excesses E B- V , and distances of stars from multicolor photometry is described. The main idea of the method is modeling the photometric data using various models for the stellar spectra and the interstellar extinction law, and applying the maximum likelihood method. The reliability of the method is estimated using stars with known spectral types and WBVR photometry, based on the empirical library of stellar spectra of Pickles and the model for the interstellar extinction law developed by Fluks et al.

  11. 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.

  12. 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

  13. 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

  14. Optical-to-IR Photometric Properties of Lyman Break Galaxies in the HDF-North

    NASA Astrophysics Data System (ADS)

    Papovich, C.; Dickinson, M.; Ferguson, H.; NICMOS HDF--N GO Team

    1999-12-01

    We present the photometric properties of Lyman Break Galaxies (LBGs) in the Hubble Deep Field North (HDF--N) using deep seven--band photometry from WFPC2 (UBVI, Williams et al. 1996), NICMOS (JH, Dickinson et al. 2000), and newly derived Ks--band photometry from ground--based KPNO data (Dickinson 1997; Papovich & Dickinson 2000). For the 27 HDF galaxies with spectroscopic redshifts 2.0 ≲ z ≲ 3.5, our photometry spans rest frame wavelengths extending from the Lyman limit through rest--frame λ 0 ≳ 5000 Angstroms. In this poster, we compare the spectral energy distributions (SEDs) of the LBGs to empirical spectral templates from Kinney et al. (1996) and Coleman, Wu, & Weedman (1980), and to population synthesis models from Bruzual & Charlot (1996). We consider general constraints on galaxy ages, star formation histories, and extinction. By selection, the LBGs contain strong, blue UV continua. In general, they are well fit by local starburst templates. To fit the SEDs of specific galaxies, most require modest but non--zero reddening. At rest--frame optical wavelengths, many galaxies show evidence for significant contributions from longer lived (A and later) stars, but none appear to be dominated by old (red) stellar populations. In some cases, there may be significant broad band flux contributions from strong nebular emission lines ([N 2]+Hα , [O 3]+Hβ , [O 2]). We discuss the implications for the evolutionary history of these galaxies using these empirical results. Support for this work is provided by NASA through grant GO-07817.01-96A.

  15. 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.

  16. T-PHOT: PSF-matched, prior-based, multiwavelength extragalactic deconfusion photometry

    NASA Astrophysics Data System (ADS)

    Merlin, E.; Fontana, A.; Ferguson, H. C.; Dunlop, J. S.; Elbaz, D.; Bourne, N.; Bruce, V. A.; Buitrago, F.; Castellano, M.; Schreiber, C.; Grazian, A.; McLure, R. J.; Okumura, K.; Shu, X.; Wang, T.; Amorín, R.; Boutsia, K.; Cappelluti, N.; Comastri, A.; Derriere, S.; Faber, S. M.; Santini, P.

    2016-09-01

    T-PHOT extracts accurate photometry from low-resolution images of extragalactic fields, where the blending of sources can be a serious problem for accurate and unbiased measurement of fluxes and colors. It gathers data from a high-resolution image of a region of the sky and uses the source positions and morphologies to obtain priors for the photometric analysis of the lower resolution image of the same field. T-PHOT handles different types of datasets as input priors, including a list of objects that will be used to obtain cutouts from the real high-resolution image, a set of analytical models (as .fits stamps), and a list of unresolved, point-like sources, useful for example for far-infrared wavelength domains. T-PHOT yields accurate estimations of fluxes within the intrinsic uncertainties of the method when systematic errors are taken into account (which can be done using a flagging code given in the output), and handles multiwavelength optical to far-infrared image photometry. T-PHOT was developed as part of the ASTRODEEP project (www.astrodeep.eu).

  17. 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).

  18. Photometry of the post-common-envelope binary PG 0308+096

    NASA Astrophysics Data System (ADS)

    Somers, M. W.; Lockley, J. J.; Naylor, T.; Wood, Janet H.

    1996-06-01

    We present R- and H-band photometry of PG 0308+096. We demonstrate that the orbital modulation is consistent with that of a dwarf M star heated by a DA white dwarf within the constraints given by the kinematic parameters. By fitting the photometry with an irradiation model we determine that the radius of the white dwarf is 0.019<=R_wd<=0.026 R_ (90 per cent confidence). In order to derive these limits, we have developed a fitting procedure that takes account of the external constraints derived from the spectroscopic analysis by Saffer et al. We determine that the period of the system is 0.286654+/-0.00000078d, which is one of the cycle count aliases considered by Saffer et al. We show that the Hα emission from the surface of the red star can be modelled as either optically thick or thin, but in the latter case the red dwarf must have intrinsic emission.

  19. 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.

  20. Wafer-level fabrication of a high-silica v-groove for fiber-optic packaging using deep dry-etching with a dual-frequency high-density plasma

    NASA Astrophysics Data System (ADS)

    Ha, Tae-Won; Heo, Gi-Seok; Choi, Bum-Ho; Kim, Young-Baek; Oh, Jin-Kyoung; Lee, Hyung-Jong

    2015-10-01

    We developed a procedure for fabricating deep silica v-grooves of about 70 μm for fiber-optic applications by using a deep dry-etching with a dual-frequency high-density plasma source. This procedure has the advantages of sub-micron precision with wafer-level productivity and a high etching speed of 0.7 μm/sec. An electro-plated hard mask as thick as 8 μm that can endure the deep dry-etch was also developed. In particular, the angular inclination of the etched groove was controllable by using the flow of C4F8 gas. A fiber array block was assembled by using a v-groove chip. The location error of the fiber cores in the block was measured to be less than 0.3 μm. This confirms that the dry-etched silica v-grooves can be applied to the packaging of optical devices with wafer-level productivity and high precision.

  1. 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

  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. Improved mm-wave photometry for kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Calvo, M.; Roesch, M.; Désert, F.-X.; Monfardini, A.; Benoit, A.; Mauskopf, P.; Ade, P.; Boudou, N.; Bourrion, O.; Camus, P.; Cruciani, A.; Doyle, S.; Hoffmann, C.; Leclercq, S.; Macias-Perez, J. F.; Ponthieu, N.; Schuster, K. F.; Tucker, C.; Vescovi, C.

    2013-03-01

    Context. We have developed a dual-band (140 and 220 GHz) mm-wave imaging camera based on superconducting kinetic inductance detector (KID) arrays. Each array contains 132 superconducting resonators whose resonant frequencies are shifted by mm-wave photons absorption. The read out is achieved with a single electronics chain per band, taking advantage of the intrinsic KID frequency-domain multiplexability. The arrays are easily scalable and well adapted for future large format focal plane instruments. NIKA (formerly Néel IRAM KID Array, now New IRAM KID Array) has been specifically designed for the IRAM 30 m telescope at Pico Veleta, and is one of the first instruments using KIDs to have made measurements of astronomical sources. Aims: In this Letter we describe the solutions adopted to improve the calibration accuracy and the sensitivity of the instrument, and we report on the outcome of the 3rd NIKA observing run of October, 2011. Methods: We use a fast electronic modulation of the readout tone for each KID pixel in order to linearize the instrument calibration, which we track with measurements of planets. We also adopt a new design of the KIDs, sensitive to both polarizations, to increase the amount of radiation absorbed and thus the optical efficiency of the system. Results: We measured an average sensitivity on the sky of 21 mJys0.5 per beam at 140 GHz and 140 mJys0.5 at 220 GHz in the best observing conditions (τ220 ≃ 0.2) after atmospheric noise decorrelation. The sensitivity at 220 GHz was limited by the atmospheric attenuation and loading as well as a reduction in the spectral bandwidth due to a misplaced filter. We found the repeatability in the photometry over the entire observing run to be better than 10% in both bands, thus demonstrating a significant improvement over the previous runs. We also find good agreement between NIKA measurements of faint astronomical sources and previous measurements of the same sources.

  4. 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)

  5. Photometry of Faint and Wide Doubles in Vulpecula

    NASA Astrophysics Data System (ADS)

    Knapp, Wilfried; Thuemen, Chris

    2016-04-01

    Images of several double stars in Vulpecula published on the "Double Star Imaging Project" Yahoo Group page suggest magnitude issues compared with the corresponding WDS catalog data per April 2015. Taking additional images with V-filter enabled photometry for these pairs, providing confirming results.

  6. Photometry of Faint and Wide Doubles in Sagitta

    NASA Astrophysics Data System (ADS)

    Knapp, Wilfried; Thuemen, Chris

    2016-02-01

    Images of several double stars in Sagitta published on the "Double Star Imaging Project" Yahoo Group page suggest magnitude issues compared with the corresponding WDS catalog data per April 2015. Taking additional images with V-filter enabled photometry for these pairs, provided confirming results.

  7. Photometry and Measurement of Faint and Wide Doubles in Eridanus

    NASA Astrophysics Data System (ADS)

    Knapp, Wilfried; Thuemen, Chris

    2015-07-01

    Images of several double stars in Eridanus published on the "Double Star Imaging Project" Yahoo Group page suggest magnitude issues compared with the corresponding WDS catalog data per 2014.12. Taking additional images with V-filter enabled photometry for these pairs with confirming results.

  8. 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.

  9. 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…

  10. 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.

  11. Research Note - Absolute UBV Photometry at the Zacatecas Observatory

    NASA Astrophysics Data System (ADS)

    Schuster, W. J.; Parrao, L.; Gonazlez-Bedolla, S. F.; Rios-Herrera, M.; Berumen, M. R.

    1985-12-01

    Atmospheric extinction data, color coefficients, errors of observation and a list of standard and comparison stars are given for UB V photometry at the Astronomical Observatory in Zacatecas. Our observing and reduction procedures are discussed briefly, and our extinction coefficients and observing errors compared with previous values. The uses of these results are mentioned.

  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. 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.

  15. Photoelectric UBV-photometry of triple-star components

    NASA Astrophysics Data System (ADS)

    Anosova, Zh. P.; Sudakov, S. V.

    Photoelectric UBV photometry has been obtained for components of 30 bright and nearby (V ⪉ 10m, r ⪉ 100 pc) triple stars for purposes of finding physically linked triple systems, their distances and the subsequent investigation of their dynamical evolution. For every component colour excesses EB-V and EU-B are determined and photometric parallaxes πph are calculated.

  16. 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.

  17. Analytical approximations of K-corrections in optical and near-infrared bands

    NASA Astrophysics Data System (ADS)

    Chilingarian, Igor V.; Melchior, Anne-Laure; Zolotukhin, Ivan Yu.

    2010-07-01

    To compare photometric properties of galaxies at different redshifts, the fluxes need to be corrected for the changes of effective rest-frame wavelengths of filter bandpasses, called K-corrections. Usual approaches to compute them are based on the template fitting of observed spectral energy distributions (SED) and, thus, require multicolour photometry. Here, we demonstrate that, in cases of widely used optical and near-infrared (NIR) filters, K-corrections can be precisely approximated as two-dimensional low-order polynomials of only two parameters: redshift and one observed colour. With this minimalist approach, we present the polynomial fitting functions for K-corrections in Sloan Digital Sky Survey (SDSS) ugriz, United Kingdom Infrared Telescope (UKIRT) Wide Field Camera YJHK, Johnson-Cousins UBVRcIc and Two Micron All Sky Survey JHKs bands for galaxies at redshifts Z < 0.5 based on empirically computed values obtained by fitting combined optical-NIR SEDs of a set of 105 galaxies constructed from SDSS Data Release 7 (DR7) and UKIRT Infrared Deep Sky Survey DR5 photometry using the Virtual Observatory. For luminous red galaxies we provide K-corrections as functions of their redshifts only. In two filters, g and r, we validate our solutions by computing K-corrections directly from SDSS DR7 spectra. We also present a K-corrections calculator, a web-based service for computing K-corrections online.

  18. 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.

  19. High-cadence, High-contrast Imaging for Exoplanet Mapping: Observations of the HR 8799 Planets with VLT/SPHERE Satellite-spot-corrected Relative Photometry

    NASA Astrophysics Data System (ADS)

    Apai, Dániel; Kasper, Markus; Skemer, Andrew; Hanson, Jake R.; Lagrange, Anne-Marie; Biller, Beth A.; Bonnefoy, Mickaël; Buenzli, Esther; Vigan, Arthur

    2016-03-01

    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%.

  20. 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.

  1. 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)

  2. 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.

  3. Absolute calibration of ultraviolet filter photometry

    NASA Technical Reports Server (NTRS)

    Bless, R. C.; Fairchild, T.; Code, A. D.

    1972-01-01

    The essential features of the calibration procedure can be divided into three parts. First, the shape of the bandpass of each photometer was determined by measuring the transmissions of the individual optical components and also by measuring the response of the photometer as a whole. Secondly, each photometer was placed in the essentially-collimated synchrotron radiation bundle maintained at a constant intensity level, and the output signal was determined from about 100 points on the objective. Finally, two or three points on the objective were illuminated by synchrotron radiation at several different intensity levels covering the dynamic range of the photometers. The output signals were placed on an absolute basis by the electron counting technique described earlier.

  4. Voyager disk-integrated photometry of Triton

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Helfenstein, P.; Verbiscer, A.; Veverka, J.; Brown, R. H.; Goguen, J.; Johnson, T. V.

    1990-01-01

    Hapke's (1981) photometric model has been combined with a plane-parallel thin atmospheric haze model to describe Voyager whole-disk observations of Triton, in the violet, blue, and green wavelength bands, in order to obtain estimates of Triton's geometric albedo, phase integral, and Bond albedo. Phase angle coverage in these filters ranging from about 12 to 159 deg was obtained by combining narrow- and wide-angle camera images. An upturn in the data at the highest phase angles observed can be explained by including scattering in a thin atmospheric haze layer with optical depths systematically decreasing with wavelength from about 0.06 in the violet to 0.03 for the green filter data.

  5. Ultraviolet photometry from the Orbiting Astronomical Observatory. XXXIII - The symbiotic star AG Pegasi

    NASA Technical Reports Server (NTRS)

    Gallagher, J. S.; Webbink, R. F.; Holm, A. V.; Anderson, C. M.

    1979-01-01

    Ultraviolet broadband photometry obtained with the Wisconsin Experiment Package on OAO 2 is presented for the symbiotic binary star AG Peg. The hot component of the binary is found to be a luminous ultraviolet source, with an energy distribution consistent with its WN6 optical spectral type. Total luminosities of 1000 and 17,000 suns are found for the hot star by assuming, respectively, that the giant primary of AG Peg is a normal M3 III star and that it fills its Roche lobe. The eruptive behavior of AG Peg is shown to require the higher luminosity, and the activity in AG Peg is discussed in terms of a very slow novalike nuclear-powered event.

  6. Scintillation correction for astronomical photometry on large and extremely large telescopes with tomographic atmospheric reconstruction

    NASA Astrophysics Data System (ADS)

    Osborn, J.

    2015-01-01

    We describe a new concept to correct for scintillation noise on high-precision photometry in large and extremely large telescopes using telemetry data from adaptive optics (AO) systems. Most wide-field AO systems designed for the current era of very large telescopes and the next generation of extremely large telescopes require several guide stars to probe the turbulent atmosphere in the volume above the telescope. These data can be used to tomographically reconstruct the atmospheric turbulence profile and phase aberrations of the wavefront in order to assist wide-field AO correction. If the wavefront aberrations and altitude of the atmospheric turbulent layers are known from this tomographic model, then the effect of the scintillation can be calculated numerically and used to normalize the photometric light curve. We show through detailed Monte Carlo simulation that for an 8 m telescope with a 16 × 16 AO system we can reduce the scintillation noise by an order of magnitude.

  7. 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..

  8. Massive Photometry of Milky Way Star Clusters from the "Vista Variables in the Vía Lactea" ESO Survey

    NASA Astrophysics Data System (ADS)

    Mauro, Francesco

    2012-12-01

    The ``VISTA Variables in the Via Lactea'' (VVV) ESO Public Survey is collecting unprecedented deep near-infrared (nIR) ZYJHKs observations of the Galactic bulge and adjacent disk. We developed the VVV-SkZ_pipeline, a DAOPHOT-based photometric pipeline, created to perform point-spread function (PSF) fitting photometry of VVV data. The pipeline permits the user to obtain PSF-fitting photometry with all of the benefits of the power and accuracy of the DAOPHOT suite, replacing the user in its repetitive interactive use in all the operations. We show that the pipeline simplifies the photometric procedure minimizing idle time, and provides an astrometrized photometric catalog reliable up to more than 2 magnitudes brighter than the saturation limit, where other techniques fail. It also produces deeper and more accurate photometry. These achievements allow VVV-SkZ_pipeline to produce data well anchored to the selected standard photometric system and analyze very important data (i.e. TRGB, RGB slope, HB morphology, RR Lyrae), that other methods either do not allow or do so in a more limited way. We present the photometric database for 36 previously known Galactic globular clusters (GGCs), plus 3 newly discovered Galactic stellar clusters. Each catalog is out to the tidal radius. Additionally to the color-magnitude diagrams, we show some of the first scientific results obtained. The opportunity to obtain reliable photometry up to more than 2 magnitudes brighter than the saturation limit was fundamental for the determination of the calibration relations for the Calcium Triplet method using nIR photometry. We obtain the calibration relations both for the equivalent widths in the Rutledge (1997) and DaCosta et al. (2009) and Saviane et al. (2012) database. We report the discovery of a peculiar horizontal branch (HB) in NGC 6440 and NGC 6569, two massive and metal-rich GGCs located in the Galactic bulge, within 4 kpc from the Galactic Center. In both clusters, two distinct

  9. 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:

  10. 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).

  11. Breaking The Quasar L-z Degeneracy Using PDF-weighted Quasar-galaxy Cross-correlations In Deep, Wide NASA Fields

    NASA Astrophysics Data System (ADS)

    Ball, Nicholas M.; Myers, A. D.; White, M.; Hickox, R. C.; Brunner, R. J.

    2010-01-01

    We present a new method for measuring the two-point correlation function, as described by Myers, White, and Ball (2009). The method is an augmentation of previous techniques that use a heterogeneous set of spectroscopic objects to anchor the distance scale, and a well-controlled set of photometric detections to reduce noise. Our new approach weights by the information present in the full photometric redshift probability density function (PDF) to dramatically improve the clustering signal. For instance, an initial test yielded a factor of 5 improvement for quasar clustering in the Sloan Digital Sky Survey. The extra signal arises because we neither express the photometric redshift as a single value nor assign a simplified PDF functional form such as a single Gaussian. Our technique is generally applicable and should be particularly useful where complex spectroscopic data sets (e.g., BOSS) are overlapped by deep photometry (e.g., Pan-STARRS, DES, or LSST). Our method depends only on photometric detections in a single survey, but additional multi-wavelength data can be used to refine the information in the PDF weighting. This makes our approach also highly suited to regions of the sky where deep, multiwavelength space surveys overlap ground-based spectroscopy (e.g., COSMOS or the Bootes Survey). We assign photometric redshift PDFs to photometrically classified galaxies detected in the optical component of COSMOS, and use PDF weights to cross-correlate them against a spectroscopically confirmed AGN sample. We also report on similar results in the Bootes Survey. The deep spectroscopy and photometry in fields such as COSMOS and Bootes will allow new investigations of how AGN cluster as a function of luminosity and type, potentially breaking the so-called L-z degeneracy. Finally, we address the often computationally intensive requirements of utilizing full PDFs. This research was funded in part by NASA ADP grant NNX08AJ28G.

  12. 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.

  13. 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.

  14. Very Late Photometry of SN 2011fe

    NASA Astrophysics Data System (ADS)

    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 56Co. 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.

  15. 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.

  16. RASNZ Photometry Section, Incorporating the Auckland Photoelectric Observers' Group

    NASA Astrophysics Data System (ADS)

    Walker, S.

    2012-06-01

    (Abstract only) This review traces the development of amateur photoelectric and CCD photometry in New Zealand from its beginnings in the late 1960s at Christchurch and Auckland, through the Auckland Photoelectric Observers' Group and the RASNZ Photometry Section to its present place in Variable Stars South. For this period of over forty years the participants have been heavily involved with southern hemisphere variable star astronomy and observatories such as Carter, Mt. John, and Auckland, together with which were sponsored the highly successful photoelectric conferences, PEP 1-5. Samples of various projects are shown and described. The full text can be seen at http://www.variablestarssouth.org/index.php/community/member-publications/posters

  17. J, H, K photometry of 433 Eros and other asteroids

    NASA Technical Reports Server (NTRS)

    Chapman, C. R.; Morrison, D.

    1976-01-01

    Results are reported for IR photometry of nine bright asteroids, including 433 Eros, which was conducted in the J, H, K, and (for Eros) L bands with an InSb photometer on the 1.3-m Kitt Peak telescope. It is found that the J-H and H-K color indices of all nine asteroids are slightly redder than those of the sun and that three C-type objects are somewhat redder in the same color indices than four S-types and an E-type. Eros is shown to have an unusually red J-K index; the shape of its IR spectral reflectance curve is attributed in part to the presence of the weak 2-micron pyroxene absorption band in the spectrum. The results show that JHK photometry is less diagnostic of asteroidal composition than higher-resolution IR spectrophotometry.

  18. Copernicus spectra and infrared photometry of 42 Orionis

    NASA Technical Reports Server (NTRS)

    Johnson, H. M.; Snow, T. P., Jr.; Gehrz, R. D.; Hackwell, J. A.

    1977-01-01

    The Orion sword star 42 Ori is embedded in a nebula north of and separated from the Orion nebula. The B1 V star is probably normal. Other members of the multiple remain poorly defined, and the nebula may exhibit some peculiarities that may depend on them. Copernicus ultraviolet spectra of the star are described here, especially in the form of tables of wavelength identifications. The properties of the interstellar material in the line of sight are also discussed. Infrared photometry is presented which suggests that the ratio of total to selective extinction ranges from 3 to 3.5 for the interstellar matter in the direction of 42 Ori. The IR photometry provides no evidence for companion stellar or circumstellar components.

  19. An Aperture Photometry Pipeline for K2 Data

    NASA Astrophysics Data System (ADS)

    Buzasi, Derek L.; Carboneau, Lindsey; Lezcano, Andy; Vydra, Ekaterina

    2016-01-01

    As part of an ongoing research program with undergraduate students at Florida Gulf Coast University, we have constructed an aperture photometry pipeline for K2 data. The pipeline performs dynamic automated aperture mask definition for all targets in the K2 fields, followed by aperture photometry and detrending. Our pipeline is currently used to support a number of projects, including studies of stellar rotation and activity, red giant asteroseismology, gyrochronology, and exoplanet searches. In addition, output is used to support an undergraduate class on exoplanets aimed at a student audience of both majors and non-majors. The pipeline is designed for both batch and single-target use, and is easily extensible to data from other missions, and pipeline output is available to the community. This paper will describe our pipeline and its capabilities and illustrate the quality of the results, drawing on all of the applications for which it is currently used.

  20. High-speed multicolour photometry with CMOS cameras

    NASA Astrophysics Data System (ADS)

    Pokhvala, S. M.; Zhilyaev, B. E.; Reshetnyk, V. M.

    2012-11-01

    We present the results of testing the commercial digital camera Nikon D90 with a CMOS sensor for high-speed photometry with a small telescope Celestron 11'' at the Peak Terskol Observatory. CMOS sensor allows to perform photometry in 3 filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system of CMOS sensors is close to the Johnson BVR system. The results of testing show that one can carry out photometric measurements with CMOS cameras for stars with the V-magnitude up to ≃14^{m} with the precision of 0.01^{m}. Stars with the V-magnitude up to ˜10 can be shot at 24 frames per second in the video mode.