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1

GRAVITY, Probing Space-time And Faint Objects In The Infrared.  

NASA Astrophysics Data System (ADS)

We introduce a new infrared adaptive optics assisted multiple-beam instrument for the VLTI infrastructure. GRAVITY (standing for General Relativity Analysis via VLT InterferometrY) will allow simultaneous observations of two objects by phase-referenced interferometric imaging and narrow angle astrometry with a high sensitivity. For those reasons, GRAVITY is particularly suited for observing various types of faint targets of deep interest in the near-infrared such as AGNs, starclusters, intermediate black holes, substellar objects, planets. Precisely, one of the main goal of GRAVITY is to probe space time around the intermediate mass black hole at the center of our galaxy. We will able to detect relativistic effects at a few Schwarzschild radii of the center of the black hole thanks to an astrometric accuracy of 10 micro arcseconds. We will present the instrumental concept of GRAVITY and discuss some of the future scientific prospects that it will offer.

Haubois, X.; Eisenhauer, F.; Perrin, G.; Rabien, S.; Eckart, A.; Lena, P.; Genzel, R.; Abuter, R.; Paumard, T.; Brandner, W.

2006-08-01

2

GRAVITY : Probing Space-Time and Faint Objects in the Infrared  

NASA Astrophysics Data System (ADS)

We introduce a new infrared adaptive optics assisted multiple-beam instrument for the VLTI infrastructure. With its high sensitivity, GRAVITY will be particularly suited for observing various types of faint targets of deep interest in the near-infrared. Precisely, one of the main goal of GRAVITY is to probe space-time at a few Schwarzschild radii of the center of the black hole located at the center of our galaxy thanks to an astrometric accuracy of 10 micro arcseconds.

Haubois, X.; Eisenhauer, F.; Perrin, G.; Rabien, S.; Eckart, A.; Lena, P.; Genzel, R.; Abuter, R.; Paumard, T.; Brandner, W.

3

A Study of Planetary Nebulae using the Faint Object Infrared Camera for the SOFIA Telescope  

NASA Technical Reports Server (NTRS)

A planetary nebula is formed following an intermediate-mass (1-8 solar M) star's evolution off of the main sequence; it undergoes a phase of mass loss whereby the stellar envelope is ejected and the core is converted into a white dwarf. Planetary nebulae often display complex morphologies such as waists or torii, rings, collimated jet-like outflows, and bipolar symmetry, but exactly how these features form is unclear. To study how the distribution of dust in the interstellar medium affects their morphology, we utilize the Faint Object InfraRed CAmera for the SOFIA Telescope (FORCAST) to obtain well-resolved images of four planetary nebulae--NGC 7027, NGC 6543, M2-9, and the Frosty Leo Nebula--at wavelengths where they radiate most of their energy. We retrieve mid infrared images at wavelengths ranging from 6.3 to 37.1 micron for each of our targets. IDL (Interactive Data Language) is used to perform basic analysis. We select M2-9 to investigate further; analyzing cross sections of the southern lobe reveals a slight limb brightening effect. Modeling the dust distribution within the lobes reveals that the thickness of the lobe walls is higher than anticipated, or rather than surrounding a vacuum surrounds a low density region of tenuous dust. Further analysis of this and other planetary nebulae is needed before drawing more specific conclusions.

Davis, Jessica

2012-01-01

4

Infrared Measurements of Faint Symbiotic Stars  

NASA Astrophysics Data System (ADS)

Far infrared IRAS measurements and near infrared observational data of nineteen faint symbiotic stars are presented in this paper. From their flux distributions and the near infrared and far infrared colours an attempt is made to study the type of these stars. The colour temperature, dust temperature and mass-loss rates are estimated from the far infrared flux ratios and compared to those of known S and D type symbiotic stars. Probably nine of them are S type, two of them are D type and three of them are D' type symbiotic stars. But it is difficult to suggest the type of five stars from the information available.

Seal, Parag

1995-12-01

5

Faint-object spectrograph for Space Telescope  

NASA Technical Reports Server (NTRS)

The paper presents the Faint Object Spectrograph (FOS) for the Space Telescope to provide a digitized spectra of faint astronomical objects over the 115 to 700 nm wavelength range at resolving powers of 1000 and 100. A variety of concave gratings and prisms is employed to form nearly stigmatic spectra on one of the two Digicon photon counting detectors which are optimized for two different but overlapping ranges. The scientific goals associated with quasars, active galaxies, and objects within our solar system are discussed, and the FOS optical design features, including detectors, electronics, signal processing, power supplies, and data handling are examined. The FOS structural system, mechanism, and controls are described, along with the predicted performance capabilities in the spectral and spectropolarimetry modes. Finally, system performance parameters, including spatial resolution, time resolution, noise, and efficiency are discussed.

Harms, r. J.; Beaver, E.; Burbidge, E. M.; Angel, R.; Bartko, F.; Bloomquist, W.; Flemming, J. C.; Bohlin, R.; Davidsen, A. F.; Ford, H.

1979-01-01

6

THE INCLINATIONS OF FAINT TRANS-NEPTUNIAN OBJECTS  

SciTech Connect

Bernstein et al. found that the population of faint (R> 26) trans-Neptunian objects (TNOs) known at that time was dominated by 'Classical' objects, which have low inclinations (i < 5{sup 0}) and distances of 40-45 AU. Since those observations, the number of faint TNOs whose orbits are sufficiently well known to be classified as 'Classical' or 'Excited' has grown from 7 to 39. We analyze the dynamical classifications of faint TNOs known today and find that this population is dominated by Excited objects. We discuss some implications of this result.

Trilling, D. E.; Fuentes, C. I. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Holman, M. J., E-mail: david.trilling@nau.ed [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2010-11-20

7

Astronomical capabilities of the Faint Object Spectrograph on Space Telescope  

NASA Technical Reports Server (NTRS)

Examples of scientific observing programs planned with the Faint Object Spectrograph on Space Telescope are presented. An overview of the spectrograph design and operation is presented. The expected astronomical performance of the instrument is described in some detail.

Harms, R. J.

1982-01-01

8

First results from the Faint Object Camera - SN 1987A  

NASA Technical Reports Server (NTRS)

The first images of SN 1987A taken on day 1278 after outburst with the Faint Object Camera on board the Hubble Space Telescope are presented. The supernova is well detected and resolved spatially in three broadband ultraviolet exposures spanning the 1500-3800 A range and in a narrow-band image centered on the forbidden O III 5007 line. Simple uniform disk fits to the profiles of SN 1987A yield an average angular diameter of 170 + or - 30 mas, corresponding to an average expansion velocity of 6000 km/s. The derived broadband ultraviolet fluxes, when corrected for interstellar absorption, indicate a blue ultraviolet spectrum corresponding to a color temperature near 13,000 K.

Jakobsen, P.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

1991-01-01

9

EVIDENCE FOR INFRARED-FAINT RADIO SOURCES AS z > 1 RADIO-LOUD ACTIVE GALACTIC NUCLEI  

SciTech Connect

Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 {mu}m) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z {approx}> 1) active galactic nuclei.

Huynh, Minh T. [Infrared Processing and Analysis Center, MS 220-6, California Institute of Technology, Pasadena, CA 91125 (United States); Norris, Ray P. [Australia Telescope National Facility, CSIRO, Epping, NSW 1710 (Australia); Siana, Brian [California Institute of Technology, MS 105-24, Pasadena, CA 91125 (United States); Middelberg, Enno, E-mail: mhuynh@ipac.caltech.ed [Astronomisches Institut, Ruhr-Universitat Bochum, Universitatsstr. 150, 44801 Bochum (Germany)

2010-02-10

10

DEEP SPITZER OBSERVATIONS OF INFRARED-FAINT RADIO SOURCES: HIGH-REDSHIFT RADIO-LOUD ACTIVE GALACTIC NUCLEI?  

SciTech Connect

Infrared-faint radio sources (IFRSs) are a rare class of objects which are relatively bright at radio wavelengths but very faint at infrared and optical wavelengths. Here we present sensitive near-infrared observations of a sample of these sources taken as part of the Spitzer Extragalactic Representative Volume Survey. Nearly all the IFRSs are undetected at a level of {approx}1 {mu}Jy in these new deep observations, and even the detections are consistent with confusion with unrelated galaxies. A stacked image implies that the median flux density is S{sub 3.6{mu}m} {approx} 0.2 {mu}Jy or less, giving extreme values of the radio-infrared flux density ratio. Comparison of these objects with known classes of object suggests that the majority are probably high-redshift radio-loud galaxies, possibly suffering from significant dust extinction.

Norris, Ray P.; Mao, Minnie [CSIRO Australia Telescope National Facility, P.O. Box 76, Epping, NSW, 1710 (Australia); Afonso, Jose [Observatorio Astronomico de Lisboa, Faculdade de Ciencias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisbon (Portugal); Cava, Antonio [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Farrah, Duncan; Oliver, Seb [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Huynh, Minh T.; Mauduit, Jean-Christophe; Surace, Jason [Infrared Processing and Analysis Center, MS220-6, California Institute of Technology, Pasadena, CA 91125 (United States); Ivison, R. J. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Jarvis, Matt [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts, AL10 9AB (United Kingdom); Lacy, Mark [NRAO, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Middelberg, Enno [Astronomisches Institut, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44801 Bochum (Germany); Seymour, Nick, E-mail: Ray.Norris@csiro.au [Mullard Space Science Laboratory, UCL, Holmbury St Mary, Dorking, Surrey, RH5 6NT (United Kingdom)

2011-07-20

11

NEUTRAL GAS OUTFLOWS AND INFLOWS IN INFRARED-FAINT SEYFERT GALAXIES  

SciTech Connect

Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an active galactic nucleus (AGN), it is unclear whether the starburst, the AGN, or both are driving the outflows. The present paper describes the results from a search for outflows in 35 infrared-faint Seyferts with 10{sup 9.9}< L{sub IR}/L{sub sun} < 10{sup 11}, or, equivalently, star formation rates (SFRs) of approx0.4-9 M{sub sun} yr{sup -1}, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert 1s (6%) and Seyfert 2s (18%) are lower than previously reported for infrared-luminous Seyfert 1s (50%) and Seyfert 2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert 2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert 1 galaxies are significantly larger. Taken together, these results suggest that the AGN does not play a significant role in driving the outflows in most infrared-faint and infrared-bright systems, except the high-velocity outflows seen in Seyfert 1 galaxies. Another striking result of this study is the high rate of detection of inflows in infrared-faint galaxies (39% of Seyfert 1s, 35% of Seyfert 2s), significantly larger than in infrared-luminous Seyferts (15%). This inflow may be contributing to the feeding of the AGN in these galaxies, and potentially provides more than enough material to power the observed nuclear activity over typical AGN lifetimes.

Krug, Hannah B.; Veilleux, Sylvain [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Rupke, David S. N., E-mail: hkrug@astro.umd.ed, E-mail: veilleux@astro.umd.ed, E-mail: drupke@ifa.hawaii.ed [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2010-01-10

12

A sample of optically faint infrared luminous galaxies  

NASA Astrophysics Data System (ADS)

We describe and discuss the optical and FIR properties of a sample of infrared luminous galaxies. The details of a subsample of eight objects as well as the optical identification of all 99 sources are given in two previous papers. Here we present the redshift and luminosity distributions and derive temperature and mass range of the IR emitting dust. Furthermore a summary of the optical line characteristics and spatial extent of line emission is given. Our analysis of the morphological peculiarities and the spectroscopic data strongly argue for interaction as the most likely trigger mechanism of the enhanced activity. Starbursts are the most general heating source and excitation scenario for our sample. We have found four new ultra-luminous IR galaxies in our survey and discuss their stage within the evolutionary scenario from starburst galaxies to quasars.

Klaas, U.; Elsaesser, H.

1993-12-01

13

The Subaru/XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey  

NASA Astrophysics Data System (ADS)

We present our survey for optically faint variable objects using multiepoch (8-10 epochs over 2-4 years) i'-band imaging data obtained with Subaru Suprime-Cam over 0.918 deg2 in the Subaru/XMM-Newton Deep Field (SXDF). We found 1040 optically variable objects by image subtraction for all the combinations of images at different epochs. This is the first statistical sample of variable objects at depths achieved with 8-10 m class telescopes or the Hubble Space Telescope. The detection limit for variable components is i'vari~25.5 mag. These variable objects were classified into variable stars, supernovae (SNe), and active galactic nuclei (AGNs), based on the optical morphologies, magnitudes, colors, and optical-mid-infrared colors of the host objects, spatial offsets of variable components from the host objects, and light curves. Detection completeness was examined by simulating light curves for periodic and irregular variability. We detected optical variability for 36%+/-2% (51%+/-3% for a bright sample with i'<24.4 mag) of X-ray sources in the field. Number densities of variable objects as functions of time intervals ?t and variable component magnitudes i'vari are obtained. Number densities of variable stars, SNe, and AGNs are 120, 489, and 579 objects deg-2, respectively. Bimodal distributions of variable stars in the color-magnitude diagrams indicate that the variable star sample consists of bright (V~22 mag) blue variable stars of the halo population and faint (V~23.5 mag) red variable stars of the disk population. There are a few candidates of RR Lyrae providing a possible number density of ~10-2 kpc-3 at a distance of >150 kpc from the Galactic center. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Based on observations (program GN-2002B-Q-30) obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (US), the Particle Physics and Astronomy Research Council (UK), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

Morokuma, Tomoki; Doi, Mamoru; Yasuda, Naoki; Akiyama, Masayuki; Sekiguchi, Kazuhiro; Furusawa, Hisanori; Ueda, Yoshihiro; Totani, Tomonori; Oda, Takeshi; Nagao, Tohru; Kashikawa, Nobunari; Murayama, Takashi; Ouchi, Masami; Watson, Mike G.; Richmond, Michael W.; Lidman, Christopher; Perlmutter, Saul; Spadafora, Anthony L.; Aldering, Greg; Wang, Lifan; Hook, Isobel M.; Knop, Rob A.

2008-03-01

14

Infrared guiding with faint stars with the wide-field infrared camera at CFHT  

NASA Astrophysics Data System (ADS)

The Canada-France-Hawaii Telescope (CFHT) is commissioning a new Wide field Infrared Camera (WIRCam) that uses a mosaic of 4 HAWAII-2RG near- infrared detectors manufactured by Rockwell. At the heart of the instrument is an On-Chip Guiding System (OCGS) that exploits the unique parallel science/guide frame readout capability of the HAWAII-2RG detectors. A small sub sample of each array is continuously read at a rate of up to 50 Hz while the integration of the science image is ongoing with the full arrays (read at a maximal rate of 1.4 s per full frame). Each of these guiding windows is centered on a star to provide an error signal for the telescope guiding. An Image Stabilizer Unit (ISU) (i.e. a tip-tilt silica plate), provides the corrections. A Proportional Integral Differential (PID) closed loop controls the ISU such that telescope tracking is corrected at a rate of 5 Hz. This paper presents the technical architecture of the guiding system and performance measurements on the sky in engineering runs with WIRCam with faint stars up to magnitude 14.

Teeple, Douglas; Riopel, Martin; Baril, Marc; Barrick, Gregory; Albert, Loic; Vermeulen, Tom; Ward, Jeff

2006-07-01

15

NOTE: Red, Gray, and Blue: Near Infrared Spectrophotometry of Faint Moons of Uranus and Neptune  

NASA Astrophysics Data System (ADS)

Using the CoCo Cold Coronagraph at NASA's Infrared Telescope Facility on Mauna Kea, we observed the uranian satellites Miranda, Puck, Portia, and Rosalind and the neptunian satellite Proteus in the near infrared (JHK) to determine the albedos of those faint satellites. In V-J, all of Puck, Portia, Rosalind, and Proteus are very blue, similar to the colors of many icy satellites and of water ice. The satellites we observed have a wide range of J-H colors, with Miranda being blue, Proteus being gray, and Puck, Portia, and Rosalind being red. For the satellites for which we could determine H-K (Miranda, Puck, and Proteus), the colors are gray to red. As a whole, spectrally, these five satellites lie between icy Solar System satellites (e.g., saturnian satellites or the major uranian satellites) and Kuiper belt objects. The redness of Proteus and Puck and perhaps other satellites suggests the presence of organic material, although the redness is also similar to that of C- and D-class asteroids and some outer jovian moons. In all cases, diagnostic spectral features could be masked by broadband photometry.

Trilling, David E.; Brown, Robert H.

2000-11-01

16

Astrometry and Photometry of Faint, High Priority Solar System Objects  

NASA Astrophysics Data System (ADS)

We request MOSAIC 1.1 on the Mayall 4-meter telescope to improve knowledge of the orbits and magnitudes of high priority classes of Near Earth Objects (NEOs) and other small solar system bodies that cannot be reached with our Spacewatch telescopes. Targets include freshly discovered virtual impactors (VIs), other close approachers, and NEOs discovered by the NEOWISE spacecraft. It is better to follow objects longer during their discovery apparitions than to search tens of degrees of arc for them when they return years later, hence the need to reach fainter magnitudes on short notice. About half of our targets are therefore unknown at the time of this proposal. Other targets for recovery include future targets of radar, NEOs previously detected by WISE with orbits or albedos suggesting potential for cometary activity, potential destinations for spacecraft, and returning NEOs with hard-won albedos and diameters determined by WISE that need astrometry. Our past use of the Mayall telescope has been determined by Co-Investigator Tim Spahr of the Minor Planet Center to provide ``dramatic improvement'' to orbits.

McMillan, Robert S.; Larsen, Jeff; Scotti, Jim; Bressi, Terry; Spahr, Tim; Maleszewski, Chet

2014-08-01

17

First results from the Faint Object Camera - Images of the gravitational lens system G2237 + 0305  

NASA Technical Reports Server (NTRS)

Images of the gravitational lens system G2237 + 0305 have been obtained with the Faint Object Camera on board the Hubble Space Telescope. A preliminary analysis of these images is reported here and includes measurements of the relative positions and magnitudes of the lensed images of the QSO, and of the lensing galaxy. No evidence is found for a fifth lensed image.

Crane, P.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

1991-01-01

18

Detailed study of FUV Jovian auroral features with the post-COSTAR HST faint object camera  

Microsoft Academic Search

A set of Hubble Space Telescope faint object camera images taken in the H2 bands near 1550 Å is used to infer the morphological properties of the steady state Jovian FUV aurorae. We focus on issues best addressed using the excellent spatial resolution available after correction of the spherical aberration, i.e., those related to high latitude or small auroral features.

Renée Prangé; Daniel Rego; Laurent Pallier; Jack Connerney; Philippe Zarka; Julien Queinnec

1998-01-01

19

FAR-INFRARED AND MOLECULAR CO EMISSION FROM THE HOST GALAXIES OF FAINT QUASARS AT z {approx} 6  

SciTech Connect

We present new millimeter and radio observations of nine z {approx} 6 quasars discovered in deep optical and near-infrared surveys. We observed the 250 GHz continuum in eight of the nine objects and detected three of them. New 1.4 GHz radio continuum data have been obtained for four sources, and one has been detected. We searched for molecular CO (6-5) line emission in the three 250 GHz detections and detected two of them. Combined with previous millimeter and radio observations, we study the far-infrared (FIR) and radio emission and quasar-host galaxy evolution with a sample of 18 z {approx} 6 quasars that are faint at UV and optical wavelengths (rest-frame 1450 A magnitudes of m{sub 1450} {>=} 20.2). The average FIR-to-active galactic nucleus (AGN) UV luminosity ratio of this faint quasar sample is about two times higher than that of the bright quasars at z {approx} 6 (m{sub 1450} < 20.2). A fit to the average FIR and AGN bolometric luminosities of both the UV/optically faint and bright z {approx} 6 quasars, and the average luminosities of samples of submillimeter/millimeter-observed quasars at z {approx} 2-5, yields a relationship of L{sub FIR} {approx} L{sub bol}{sup 0.62}. Five of the 18 faint z {approx} 6 quasars have been detected at 250 GHz. These 250 GHz detections, as well as most of the millimeter-detected optically bright z {approx} 6 quasars, follow a shallower trend of L{sub FIR} {approx} L{sub bol}{sup 0.45} defined by the starburst-AGN systems in local and high-z universe. The millimeter continuum detections in the five objects and molecular CO detections in three of them reveal a few x 10{sup 8} M{sub sun} of FIR-emitting warm dust and 10{sup 10} M{sub sun} of molecular gas in the quasar host galaxies. All these results argue for massive star formation in the quasar host galaxies, with estimated star formation rates of a few hundred M{sub sun} yr{sup -1}. Additionally, the higher FIR-to-AGN luminosity ratio found in these 250 GHz detected faint quasars also suggests a higher ratio between star formation rate and supermassive black hole accretion rate than the UV/optically most luminous quasars at z {approx} 6.

Wang Ran; Wagg, Jeff; Carilli, Chris L. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Neri, Roberto [Institute de Radioastronomie Millimetrique, St. Martin d'Heres F-38406 (France); Walter, Fabian [Max-Planck-Institute for Astronomy, Koenigsstuhl 17, 69117 Heidelberg (Germany); Omont, Alain [Institut d'Astrophysique de Paris, CNRS and Universite Pierre et Marie Curie, Paris (France); Riechers, Dominik A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bertoldi, Frank [Argelander-Institut fuer Astronomie, University of Bonn, Auf dem Huegel 71, 53121 Bonn (Germany); Menten, Karl M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 71, 53121 Bonn (Germany); Cox, Pierre [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile); Strauss, Michael A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Fan Xiaohui; Jiang Linhua [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2011-10-15

20

The faint limit of the Hubble Space Telescope faint object spectrograph and rejection of the cosmic-ray background  

NASA Technical Reports Server (NTRS)

The faintest object which can be observed with the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) is set by the detector cosmic-ray background and not by object flux. We use data from Beaver and Lyons to show that 48% of the background counts are from cosmic rays which each generate a near instantaneous burst of two or more counts. Setting the FOS threshold parameter REJLIM = 1, which rejects all frames with more than one count increases the ratio of signal-to-dark counts (S/D) by a factor of 1.94, regardless of the frame time or the object signal, because half of the dark counts which arrive in single counts (from either cosmic-ray bursts or thermal dark current photoemission) are rejected at the same rate as the object signal. But the signal-to-noise ratio (SNR proportional to S/square root of S + D) increases by at most a factor of 1.35, and for realistic parameters and taking into account dead time, we expect a gain in SNR of only 1.18. If a diode has failed and now emits noise, no data at all will be recorded. The chance of this occurring is approximately = 10% , and for this reason we do not recommend the use of REJLIM. The two-point correlation function of dark counts per pixel has strong peaks every four pixels, caused by the action of quarter-stepping on the counts from large bursts. The counts from such bursts spread over at least 80-100 diodes, and we show that such bursts can be rejected during data reduction if the data are recorded in RAPID mode with individual exposures of about 35 seconds. The SNR of the spectrum can also be improved by weighting each exposure by its SNR (a function ofthe mean dark count rate at that time), since dark varies by a factor of 2 around an orbit. These two procedures together increase the SNR by a factor of 1.1.3 (a 28% gain in exposure time) in regions of a spectrum where the object is much fainter than the background. We find that the Ly-alpha and O I sky emission lines give at most 4 (counts/array/s/sq arcsec), and typically half this number. With a small frame time and a small entrance aperture, these counts cause REJLIM = 1 to reject only a few percent of the data. We discuss only the HST FOS blue side detector, but the same ideas apply to any photon counter which records bursts of noise, and the calculations resemble those for the loss of signal due to coincidences in photon counters. In the ideal photon counter the dark counts are readily distinguished from photons. One way to do this is to add detectors which records only dark current, so that every cosmic ray produces more than one count and the instrument can be operated in an anti-coincidence mode.

Tytler, David; Davis, Christopher

1995-01-01

21

Rocket instrument for far-UV spectrophotometry of faint astronomical objects  

NASA Technical Reports Server (NTRS)

A sensitive sounding rocket instrument for moderate (about 10-A) resolution far-UV (1160-1750-A) spectrophotometry of faint astronomical objects has been developed. The instrument employes a photon-counting microchannel plate imaging detector and a concave grating spectrograph behind a 40-cm Dall-Kirkham telescope. A unique remote-control pointing system, incorporating an SIT vidicon aspect camera, two star trackers, and a tone-encoded command telemetry link, permits the telescope to be oriented to within 5 arc sec of any target for which suitable guide stars can be found. The design, construction, calibration, and flight performance of the instrument are discussed.

Hartig, G. F.; Fastie, W. G.; Davidsen, A. F.

1980-01-01

22

Rocket instrument for far-UV spectrophotometry of faint astronomical objects.  

PubMed

A sensitive sounding rocket instrument for moderate (~10-A) resolution far-UV (lambda1160-lambda1750-A) spectrophotometry of faint astronomical objects has been developed. The instrument employs a photon-counting microchannel plate imaging detector and a concave grating spectrograph behind a 40-cm Dall-Kirkham telescope. A unique remote-control pointing system, incorporating an SIT vidicon aspect camera, two star trackers, and a tone-encoded command telemetry link, permits the telescope to be oriented to within 5 arc sec of any target for which suitable guide stars can be found. The design, construction, calibration, and flight performance of the instrument are discussed. PMID:20220923

Hartig, G F; Fastie, W G; Davidsen, A F

1980-03-01

23

First results from the Faint Object Camera - Observations of PKS 0521 - 36  

NASA Technical Reports Server (NTRS)

The Faint Object Camera on the Hubble Space Telescope was used to observe the radio galaxy PKS 0521 - 36 which hosts a prominent radio jet. Images of the jet show spatial structure comparable to VLA data and significantly better than optical ground-based observations. The jet structure is resolved at FOC resolution. In addition to the radio knot, well resolved by the FOC, an extension of the jet toward the nucleus is apparent. The rest of the jet does not show much clumpiness, implying that the synchrotron electrons must be accelerated all along the jet to account for the extent in the optical region.

Macchetto, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

1991-01-01

24

Hubble Space Telescope: Faint object camera instrument handbook. Version 2.0  

NASA Technical Reports Server (NTRS)

The Faint Object Camera (FOC) is a long focal ratio, photon counting device designed to take high resolution two dimensional images of areas of the sky up to 44 by 44 arcseconds squared in size, with pixel dimensions as small as 0.0007 by 0.0007 arcseconds squared in the 1150 to 6500 A wavelength range. The basic aim of the handbook is to make relevant information about the FOC available to a wide range of astronomers, many of whom may wish to apply for HST observing time. The FOC, as presently configured, is briefly described, and some basic performance parameters are summarized. Also included are detailed performance parameters and instructions on how to derive approximate FOC exposure times for the proposed targets.

Paresce, Francesco (editor)

1990-01-01

25

H{alpha} DOTS: A CATALOG OF FAINT EMISSION-LINE OBJECTS DISCOVERED IN NARROWBAND IMAGES  

SciTech Connect

During a wide-field narrowband H{alpha} imaging survey, we noted the presence of numerous isolated emission-line point sources in the data. These objects could represent ultra-low-luminosity galaxies at low-redshift (detection via H{alpha}), isolated extragalactic H II regions associated with the galaxy targeted by the original observation, or background galaxies or QSOs where strong emission lines (most often [O III] {lambda}5007) redshift into our narrowband filter. We have carried out a systematic search for these 'H{alpha} dots' in over 200 15 Multiplication-Sign 15 arcmin fields. To date we have cataloged 61 candidate emission-line sources in roughly 11.7 deg{sup 2}. The sample has a median R magnitude of 19.5, and detects objects as faint as R = 22.6. Follow-up spectroscopy reveals that {approx}85% of the candidates are bona fide emission-line objects, with roughly 60% of the real sources being lower-redshift objects (detection via H{alpha}) and 40% being higher-redshift objects detected via [O III] emission or some other emission line. Here we present the results of our initial survey and follow-up spectroscopy. We use our sample to study the properties (including star-formation rates and metal abundances) of low-luminosity star-forming galaxies in the nearby universe and of low-metallicity star-forming galaxies at z Almost-Equal-To 0.33.

Kellar, Jessica A.; Wegner, Gary [Department of Physics and Astronomy, 6127 Wilder Laboratory, Dartmouth College, Hanover, NH 03755 (United States); Salzer, John J.; Williams, Anna [Department of Astronomy, Indiana University, 727 East Third Street, Bloomington, IN 47405 (United States); Gronwall, Caryl, E-mail: jessica.a.kellar@dartmouth.edu, E-mail: gaw@northstar.dartmouth.edu, E-mail: slaz@astro.indiana.edu, E-mail: caryl@astro.psu.edu, E-mail: williams@astro.wisc.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

2012-06-15

26

Astrometric and Photometric Follow-Up of Faint Near Earth Objects  

NASA Technical Reports Server (NTRS)

During the last year, the Near-Earth Object (NEO) follow-up program at Mt. Hopkins funded by the Near-Earth Object Observations (NEOO) program continued to improve. The Principal Investigator was again granted all the requested observing time. In addition to the requested time on the 4 8 in. telescope, 2 nights were also granted on the MMT for observations of extremely faint main-belt asteroids and NEOs. It is expected that the MMT can easily reach V = 25 over a 24 X 24 arcminute field of view. Improvements in the last year included more tweaks to the automatic astrometric routine for higher-quality astrometric fits. Use of the new USNO-B1.0 reference catalog has allowed the PI to push the average RMS of reference star solutions below 0.2 in.. Shift-and- stack techniques are used to improve the signal-to-noise ratio of the target objects. The 48 in. telescope at Mt. Hopkins is completely automated, and can be run remotely from either the Principal Investigator's office at SAO, or even his study at home. Most observing runs are now done remotely.

Spahr, Timothy

2004-01-01

27

Measurements of the sky background using the HST Faint Object Camera.  

NASA Astrophysics Data System (ADS)

The results of a novel method of measuring the three dominant components of the sky brightness from the Hubble Space Telescope orbit are reported. The shadows cast by an occulting finger in the Faint Object Camera (FOC), when the field is dispersed with an objective prism, are separated into three features: the geocoronal Ly? and neutral oxygen airglow emission lines in the far ultraviolet, and the zodiacal light continuum above 3000 A. These are measured as functions of the relevant angles in the spacecraft-earth-sun geometry. The measurements are compared with predictions derived from models. Satisfactory agreement is found when the revised f/96 detector quantum efficiency of the FOC is used. The zodiacal light is well within the expected range of 70-210 S10 units for the observed ecliptic coordinates. The Ly? emission background is 25% lower than expected for all solar zenith distances. There is an excess of OI emission, by a factor of two above the predictions. There is a weak correlation between the Ly? emission and the target zenith distance.

Caulet, A.; Hook, R. N.; Fosbury, R. A. E.

1994-12-01

28

Far-infrared properties of submillimeter and optically faint radio galaxies  

NASA Astrophysics Data System (ADS)

We use deep observations obtained with the Photodetector Array Camera and Spectrometer (PACS) onboard the Herschel Space Observatory to study the far-infrared (FIR) properties of submillimeter and optically faint radio galaxies (SMGs and OFRGs). From literature we compiled a sample of 35 securely identified SMGs and nine OFRGs located in the GOODS-N and the A2218 fields. This sample is cross-matched with our PACS 100 ?m and 160 ?m multi-wavelength catalogs based on sources-extraction using prior detections at 24 ?m. About half of the galaxies in our sample are detected in at least the PACS 160 ?m bandpass. The dust temperatures and the infrared luminosities of our galaxies are derived by fitting their PACS and SCUBA 850 ?m (only the upper limits for the OFRGs) flux densities with a single modified (? = 1.5) black body function. The median dust temperature of our SMG sample is Tdust = 36±8 K while for our OFRG sample it is Tdust = 47±3 K. For both samples, median dust temperatures derived from Herschel data agree well with previous estimates. In particular, Chapman et al. (2005, ApJ, 622, 772) found a dust temperature of Tdust = 36±7 K for a large sample of SMGs assuming the validity of the FIR/radio correlation (i.e., q= log10(LFIR[W]/L1.4 GHz[W Hz-1] /3.75×1012)). The agreement between our studies confirms that the local FIR/radio correlation effectively holds at high redshift even though we find < q > = 2.17±0.19, a slightly lower value than that observed in local systems. The median infrared luminosities of SMGs and OFRGs are 4.6×1012 L? and 2.6×1012 L?, respectively. We note that for both samples the infrared luminosity estimates from the radio part of the spectral energy distribution (SED) are accurate, while estimates from the mid-IR are considerably (~×3) more uncertain. Our observations confirm the remarkably high luminosities of SMGs and thus imply median star-formation rates of 960 M? yr-1 for SMGs with S(850 ?m)>5 mJy and 460 M? yr-1 for SMGs with S(850 ?m)>2 mJy, assuming a Chabrier IMF and no dominant AGN contribution to the far-infrared luminosity. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Magnelli, B.; Lutz, D.; Berta, S.; Altieri, B.; Andreani, P.; Aussel, H.; Castañeda, H.; Cava, A.; Cepa, J.; Cimatti, A.; Daddi, E.; Dannerbauer, H.; Dominguez, H.; Elbaz, D.; Förster Schreiber, N.; Genzel, R.; Grazian, A.; Gruppioni, C.; Magdis, G.; Maiolino, R.; Nordon, R.; Pérez Fournon, I.; Pérez García, I.; Poglitsch, A.; Popesso, P.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Saintonge, A.; Santini, P.; Sanchez-Portal, M.; Shao, L.; Sturm, E.; Tacconi, L.; Valtchanov, I.; Wieprecht, E.; Wiezorrek, E.

2010-07-01

29

First results from the faint object camera - High-resolution imaging of the Pluto-Charon system  

NASA Technical Reports Server (NTRS)

The first observations of a solar system target with the Faint Object Camera of the HST are reported. Observations of the Pluto-Charon system were obtained in f/96 and f/288 mode. Pluto and Charon were clearly resolved, and the observed separation and diameters are in accordance with expectations. The f/96 data were astrometrically and photometrically analyzed; preliminary results are presented.

Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.; Crane, P.

1991-01-01

30

Thermal balance qualification testing of the thermal control system of the Faint Object Camera  

NASA Astrophysics Data System (ADS)

The stringent image stability requirements (better than 6.5 microns) on the Faint Object Camera (FOC) on the Space Telescope necessitate an active thermal control system to provide for the stability of the optical bench, optical heads and detector head unit during data acquisition. The paper presents results of the thermal performance testing of the FOC thermal control system under simulated flight conditions. The Structure Thermal Module of the FOC, which includes an arrangement of computer-controlled heaters, multi-layer insulation and radiators to provide for thermal stability, was tested in environments corresponding to transient initial deployment without power, steady-state operation in a fixed power mode, a cold hold mode, warm-up from hold to cold operation, transition from cold to intermediate operation, and hot operation. Measurements of image displacement and temperature variations demonstrate that the control system can easily achieve the specified image stability, long-term temperature stability at 17 + or - 2 C, and short-term temperature stability to within less than 0.25 C.

Jaekel, E.; Best, R.; Camus, J. P.; Soulat, G.

1982-06-01

31

Faint Object Camera observations of M87 - The jet and nucleus  

NASA Technical Reports Server (NTRS)

UV and optical images of the central region and jet of the nearby elliptical galaxy M87 have been obtained with about 0.1 arcsec resolution in several spectral bands with the Faint Object Camera (FOC) on the HST, including polarization images. Deconvolution enhances the contrast of the complex structure and filamentary patterns in the jet already evident in the aberrated images. Morphologically there is close similarity between the FOC images of the extended jet and the best 2-cm radio maps obtained at similar resolution, and the magnetic field vectors from the UV and radio polarimetric data also correspond well. We observe structure in the inner jet within a few tenths arcsec of the nucleus which also has been well studied at radio wavelengths. Our UV and optical photometry of regions along the jet shows little variation in spectral index from the value 1.0 between markedly different regions and no trend to a steepening spectrum with distance along the jet.

Boksenberg, A.; Macchetto, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

1992-01-01

32

Correction of the geomagnetically induced image motion problem on the Hubble Space Telescope's Faint Object Spectrograph  

NASA Astrophysics Data System (ADS)

During the Science Verification phase of the Hubble Space Telescope mission, it was determined that the Faint Object Spectrograph's (FOS) Red detector displayed significant image motions which correlated with orbital changes in the geomagnetic field. The Blue detector exhibited similar but less pronounced motions. The cause of this motion was determined to be inadequate magnetic shielding of the instrument's Digicon detectors. The results of these motions were decreases in onboard target acquisition accuracy, spectral resolution, and photometric accuracy. The Space Telescope Science Institute and the FOS Investigation Definition Team, set about correcting this Geomagnetically-induced Image Motion Problem (GIMP) through a real-time on-board correction scheme. This correction required modifications to almost all aspects of the HST ground system as well as additional NSSC1 flight software and the use of an existing software 'hook' in the FOS microprocessor firmware. This paper presents a detailed description of the problem, the proposed solution, and results of on-orbit testing of the correction mechanism.

Fitch, John E.; Hartig, George F.; Beaver, Edward A.; Hier, Richard G.

1993-11-01

33

First results from the Faint Object Camera - Imaging the core of R Aquarii  

NASA Technical Reports Server (NTRS)

The Faint Object Camera on the HST was pointed toward the symbiotic long-period M7e Mira variable R Aquarii, and very high resolution images of the inner core, mainly in the ionized oxygen emission lines in the optical, are reported. Both images show bright arcs, knots, and filaments superposed on a fainter, diffuse nebulosity extending in a general SW-NE direction from the variable to the edge of the field at 10 arcsec distance. The core is resolved in forbidden O III 5007 A and forbidden O II 3727 A into at least two bright knots of emission whose positions and structures are aligned with PA = 50 deg. The central knots appear to be the source of a continuous, well-collimated, stream of material extending out to 3-4 arcsec in the northern sector corresponding to a linear distance of about 1000 AU. The northern stream seems to bend around an opaque obstacle and form a spiral before breaking up into wisps and knots. The southern stream is composed of smaller, discrete parcels of emitting gas curving to the SE.

Paresce, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

1991-01-01

34

On the nature of faint mid-infrared sources in M 33  

NASA Astrophysics Data System (ADS)

Aims: We investigate the nature of 24 ?m sources in M 33 that have weak or no associated H? emission. Both bright evolved stars and embedded star-forming regions are visible as compact infrared sources in the 8 and 24 ?m Spitzer maps of M 33 and contribute to the more diffuse and faint emission in these bands. Can we distinguish the two populations? Methods: We carry out deep CO J = 2-1 and J = 1-0 line searches at the location of 18 compact mid-IR sources and two optically selected ones to unveil an ongoing star formation process throughout the disk of M 33. In the absence of high-resolution CO maps we use different assumptions to estimate cloud masses from pointed observations. We also analyze if the spectral energy distribution and mid-IR colors can be used to discriminate between evolved stars and star-forming regions. Results: Molecular emission is detected at the location of 17 sources at the level of 0.3 K km s-1 or higher in at least one of the CO rotational lines. Even though the number of giant molecular clouds drops beyond 4 kpc in M 33, our deep observations reveal that clouds of smaller mass are common out to 6.8 kpc. Estimated cloud masses range between 104 and 105 M?, assuming likely values of the CO-to-H2 conversion factor and virial equilibrium. Sources that are known to be evolved variable stars show weaker or undetectable CO lines. Evolved stars occupy a well defined region of the IRAC color-color diagrams. Star-forming regions are scattered throughout a larger area, even though the bulk of the distribution has different IRAC colors than evolved variable stars. We estimate that about half of the 24 ?m sources without an H? counterpart are genuine embedded star-forming regions. Sources with faint but compact H? emission have an incomplete Initial Mass Function (IMF) at the high-mass end and are compatible with a population of young clusters with a stochastically sampled, universal IMF.

Corbelli, E.; Giovanardi, C.; Palla, F.; Verley, S.

2011-04-01

35

Far-ultraviolet spectroscopy of the quasar UM 675 with the faint object spectrograph on the Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

To investigate the far-UV spectral properties of a QSO and to look for evidence of He I 584 A emission and absorption the Faint Object Spectrograph aboard the HST was used to observed UM 675. Light is detected down to 520 A in the object in the rest frame and limits are set to He I emission, the He I Gunn-Peterson effect at z = 2.148, and Ly-alpha absorption at z roughly 0.5.

Beaver, E. A.; Burbidge, E. M.; Cohen, Ross D.; Junkkarinen, Vesa T.; Lyons, Ronald W.

1991-01-01

36

Mars ozone measurements near the 1995 aphelion: Hubble space telescope ultraviolet spectroscopy with the faint object spectrograph  

Microsoft Academic Search

Ultraviolet (225-330 nm) spectral scans of Mars were obtained with the Hubble space telescope (HST) faint object spectrograph (FOS) in February of 1995. These spectra yield ozone column abundances, cloud opacities (0.2-0.4 at low latitudes), and polar seasonal ice albedos from southern midlatitudes to northern high latitudes on Mars. At the time of these measurements, Mars was at a solar

R. Todd Clancy; Michael J. Wolff; Philip B. James; Ed Smith; Youssef N. Billawala; Steven W. Lee; Michael Callan

1996-01-01

37

High-resolution imaging of the Pluto-Charon system with the Faint Object Camera of the Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

Images of the Pluto-Charon system were obtained with the Faint Object Camera (FOC) of the Hubble Space Telescope (HST) after the refurbishment of the telescope. The images are of superb quality, allowing the determination of radii, fluxes, and albedos. Attempts were made to improve the resolution of the already diffraction limited images by image restoration. These yielded indications of surface albedo distributions qualitatively consistent with models derived from observations of Pluto-Charon mutual eclipses.

Albrecht, R.; Barbieri, C.; Adorf, H.-M.; Corrain, G.; Gemmo, A.; Greenfield, P.; Hainaut, O.; Hook, R. N.; Tholen, D. J.; Blades, J. C.

1994-01-01

38

Colour Object Classification Using the Fusion of Visible and Near-Infrared Spectra  

Microsoft Academic Search

\\u000a Under extreme light conditions, a conventional colour CCD camera would fail to render the colours of an object properly as\\u000a the visible spectrum is either faintly observable in the scene or the presence of glare corrupts the colours sensed. On the\\u000a other hand, for darkly-illuminated areas, a near-infrared (NIR) camera would sense stronger more discriminable signals, but\\u000a could only render

Heesang Shin; Napoleon H. Reyes; Andre L. C. Barczak; Chee Seng Chan

2010-01-01

39

First results from the faint object camera - High-resolution observations of the central object R136 in the 30 Doradus nebula  

NASA Technical Reports Server (NTRS)

R136 is the luminous central object of the giant H II region 30 Doradus in the LMC. The first high-resolution observations of R136 with the Faint Object Camera on board the Hubble Space Telescope are reported. The physical nature of the brightest component R136a has been a matter of some controversy over the last few years. The UV images obtained show that R136a is a very compact star cluster consisting of more than eight stars within 0.7 arcsec diameter. From these high-resolution images a mass upper limit can be derived for the most luminous stars observed in R136.

Weigelt, G.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

1991-01-01

40

Infrared interferometric observations of young stellar objects  

Microsoft Academic Search

We present infrared observations of four young stellar objects using the\\u000aPalomar Testbed Interferometer (PTI). For three of the sources, T Tau, MWC 147\\u000aand SU Aur, the 2.2 micron emission is resolved at PTI's nominal fringe spacing\\u000aof 4 milliarcsec (mas), while the emission region of AB Aur is over-resolved on\\u000athis scale. We fit the observations with simple

R. L. Akeson; D. R. Ciardi; G. T. van Belle; M. J. Creech-Eakman; E. A. Lada

2000-01-01

41

Hubble Space Telescope Faint Object Spectrograph and ground-based observations of the broad absorption line quasar 0226-1024  

NASA Technical Reports Server (NTRS)

Faint Object Spectrograph data from the Hubble Space Telescope of the broad absorption line quasar 0226-1024 have revealed the presence of 8-10 absorbing ions between 680 and 1000 A (restframe): C III, N III, N IV, O III, O IV, O VI, S V, S VI, possibly Ne VIII, and possibly O V* arising from a metastable excited state. We also present ground-based optical observations of the broad line troughs for the following ions: H I, C IV, N V, Si IV, and possibly Fe III, S IV, P V, and C III* (also arising from a metastable excited state). The results of this fit are used to estimate the absorbing ionic column densities. There is evidence that the broad absorption line clouds are optically thick and either do not completely cover the continuum source or narrow unresolved lines are present.

Korista, Kirk T.; Weymann, Ray J.; Morris, Simon L.; Kopko, Michael, Jr.; Turnshek, David A.; Hartig, George F.; Foltz, Craig B.; Burbidge, E. M.; Junkkarinen, Vesa T.

1992-01-01

42

A new network of faint calibration stars from the near infrared spectrometer (NIRS) on the IRTS  

NASA Technical Reports Server (NTRS)

The point source extraction and calibration of the near infrared spectrometer (NIRS) onboard the Infrared Telescope in Space (IRTS) is described. About 7 percent of the sky was observed during a one month mission in the range of 1.4 micrometers to 4 micrometers. The accuracy of the spectral shape and absolute values of calibration stars provided by the NIRS/IRTS were validated.

Freund, Minoru M.; Matsuura, Mikako; Murakami, Hiroshi; Cohen, Martin; Noda, Manabu; Matsuura, Shuji; Matsumoto, Toshio

1997-01-01

43

Minor planets and related objects. XXV - UBV photometry of 145 faint asteroids  

NASA Technical Reports Server (NTRS)

Magnitudes and colors on the UBV system are presented for 145 minor planets, including 31 objects in the Eos family, 14 in the Koronis family, 6 in the Nysa family, 11 in the Themis family, 4 Hungarias, 7 Hildas, 8 Trojans, and several objects in unusual orbits. Clearly defined color groups for the Eos, Koronis, Nysa, and Themis family members are strongly suggestive of origin from discrete parent bodies. The Nysas apparently show large light-curve amplitudes. The Mars-orbit crossers 1977RA and 1980 = 1950LA, the earth-orbit crosser 1976UA, and several main-belt asteroids are found to show peculiar colors of unknown significance. The Mars-orbit crosser 1916 = 1953RA appears to be a typical S object, while 1474 Beira and 1977VA show neutral colors. Asteroids at semimajor axis in excess of 4 AU (Trojans preceding and following Jupiter, 279 Thule, and 944 Hidalgo) all belong to a color group centered at B-V = 0.72, U-B = 0.24.

Degewij, J.; Gradie, J.; Zellner, B.

1978-01-01

44

Infrared multi-object spectrograph of MOIRCS  

NASA Astrophysics Data System (ADS)

The design, development, operation and current performance of MOS (multi-object spectroscopy) mode of MOIRCS is described. MOIRCS (Multi-Object Infrared Camera and Spectrograph) is one of the second-generation instruments for the Subaru Telescope and provides imaging and MOS modes with a 4' × 7' field of view for a wavelength range from 0.85 to 2.5 ?m. To achieve near-infrared (NIR) MOS up to K-band, MOS mode uses multi-slit masks and a mask exchange system in a cryogenic environment. The masks are housed in a vacuum dewar attached to the MOIRCS main dewar and separated by a large gate valve. The mask dewar is equipped with its own cryogenic cooler and a vacuum pump and is capable of storing eighteen masks. The masks are made of thin aluminum foil. Slits are cut with a laser, with software that corrects for the effects of thermal contraction. The masks are cooled to below 130 K in the mask dewar and transported to the focal plane in the main dewar through the gate valve with a linear motion manipulator. An interlock is equipped on the mask exchange system to secure the cryogenic instrument from accident. Replacing masks can be done in the daytime without breaking the vacuum of the main dewar by isolating the mask dewar with the gate valve. Acquisition occurs by iteratively taking on-sky images through alignment holes on the mask until the rotation and offset between alignment stars and alignment holes become small enough. MOIRCS/MOS mode will be open to the public in late 2006.

Tokoku, Chihiro; Suzuki, Ryuji; Omata, Koji; Konishi, Masahiro; Yoshikawa, Tomohiro; Akiyama, Masayuki; Tanaka, Ichi; Ichikawa, Takashi; Nishimura, Tetsuo

2006-07-01

45

Imaging of four planetary nebulae in the Magellanic Clouds using the Hubble Space Telescope Faint Object Camera  

NASA Technical Reports Server (NTRS)

Using the Faint Object Camera on-board the Hubble Space Telescope, we have obtained images of four planetary nebulae (PNe) in the Magellanic Clouds, namely N2 and N5 in the SMC and N66 and N201 in the LMC. Each nebula was imaged through two narrow-band filters isolating forbidden O III 5007 and H-beta, for a nominal exposure time of 1000 s in each filter. In forbidden O III, SMC N5 shows a circular ring structure, with a peak-to-peak diameter of 0.26 arcsec and a FWHM of 0.35 arcsec while SMC N2 shows an elliptical ring structure with a peak-to-peak diameter of 0.26 x 0.21. The expansion ages corresponding to the observed structures in SMC N2 and N5 are of the order of 3000 yr. LMC N201 is very compact, with a FWHM of 0.2 arcsec in H-beta. The Type I PN LMC N66 is a multipolar nebula, with the brightest part having an extent of about 2 arcsec and with fainter structures extending over 4 arcsec.

Blades, J. C.; Barlow, M. J.; Albrecht, R.; Barbieri, C.; Boksenberg, A.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

1992-01-01

46

Fainting (Syncope)  

MedlinePLUS

... Attack Heart Valve Problems Join our e-newsletter! Aging & Health A to Z Fainting (Syncope) Basic Facts & Information ... year. Updated: March 2012 Posted: March 2012 © 2014 Health in Aging. All rights reserved. Feedback • Site Map • Privacy Policy • ...

47

Infrared Detection and Characterization of Near Earth Objects  

Microsoft Academic Search

Infrared detection from space offers an invaluable adjunct to ground based visible searches for the discovery and characterization of Near Earth Objects (NEOs). The known Near Earth Objects are predominately highly reflective, presumably due to a discovery bias against dark objects inherent in visual surveys. For a given diameter, dark objects are at least a factor of four fainter in

M. P. Egan; S. D. Price; E. F. Tedesco

1998-01-01

48

Infrared system for monitoring movement of objects  

Microsoft Academic Search

A system is described for monitoring moving objects, such as the flight of honeybees and other insects, using a pulsed laser light source. This system has a self-powered micro-miniaturized transmitting unit powered, in the preferred embodiment, with an array of solar cells. This transmitting unit is attached to the object to be monitored. These solar cells provide current to a

K. H. Valentine; D. D. Falter; K. G. Falter

1991-01-01

49

Infrared system for monitoring movement of objects  

Microsoft Academic Search

A system for monitoring moving objects, such as the flight of honeybees and other insects, using a pulsed laser light source. This system has a self-powered micro-miniaturized transmitting unit powered, in the preferred embodiment, with an array solar cells. This transmitting unit is attached to the object to be monitored. These solar cells provide current to a storage energy capacitor

Kenneth H. Valentine; Diedre D. Falter; Kelly G. Falter

1991-01-01

50

[Calculation of infrared temperature measurement on non-Lambertian objects].  

PubMed

According to the theory of infrared radiation and principles of temperature measurement using infrared imager, a universal mathematical model of infrared imager is established. Based on the normal emissivity characteristics of measured surface, the mathematical model is simplified, and the formula of temperature measurement using infrared imager is obtained. Through the relevant experiment, it is proved that the sum of emissivity and reflectivity of objects remained basically unchanged in a certain temperature range. The sum of emissivity and reflectivity of objects is relevant to the object types, surface conditions and the object temperature. The closer an object to Lambertian objects, the greater the sum is and the closer it is to 1. The farther the surface conditions deviate from the Lambertian surface, or the smoother the surface, the smaller the sum is. Experimental results show that if the object is close to Lambertian objects, it could be regarded as Lambertian, without the need for amendments to the actual objects. For non-Lambertian body (especially the smooth surfaces and low-emissivity objects), the amendment is necessary, or the temperature measurement error will increase, or even the obtained temperature is very far away from its true temperature. The study shows that, through the amendment, infrared temperature measurement on non-Lambertian objects is available. PMID:20939314

Yang, Zhen; Zhang, Shi-cheng; Yang, Li

2010-08-01

51

Infrared Array Camera (IRAC) Colors of Young Stellar Objects  

Microsoft Academic Search

We compare the infrared colors predicted by theoretical models of protostellar envelopes and protoplanetary disks with initial observations of young stellar objects made with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. Disk and envelope models characterized by infall and\\/or accretion rates found in previous studies can quantitatively account for the range of IRAC colors found in four

Lori E. Allen; Nuria Calvet; Paola D'Alessio; Bruno Merin; Lee Hartmann; S. Thomas Megeath; Robert A. Gutermuth; James Muzerolle; Judith L. Pipher; Philip C. Myers; Giovanni G. Fazio

2004-01-01

52

On the variable nature of galactic and extra-galactic objects with sources from the Faint Sky Variability Survey  

NASA Astrophysics Data System (ADS)

The Faint Sky Variability Survey (FSVS) has cataloged ˜23 square degrees in BVI filters from ˜16 25 mag to investigate variability in faint sources at moderate to high Galactic latitudes. Multi-epoch (10 30) observations were made in V spanning minutes to years with amplitude sensitivities of ˜0.015 0.075 mag for V = 18 22 mag. The fraction of point sources found to be variable is 5 8% over V = 17.5 22.0 mag. Overall, the dominant population of variable sources are bluer than B-V = 0.65 and have Main Sequence colors, likely reflecting larger populations of RR Lyrae, SX Phe, ? Doradus, and W UMa variables. The population of ultracool dwarfs has been investigated using a V-I color selection. An L2 dwarf is the coolest source thus far spectroscopically identified with candidates predicted as cool as L8. Variability information for ultracool dwarfs is limited as the cooler sources become exceedingly faint in V, and thus, variability information only reaches to mid-late M type dwarfs. Follow-up photometry in the I has revealed variability in an M8 9 and L2 dwarf, with the M8 9 dwarf showing a 3 hour periodicity likely attributable to rotational modulation of surface features. The population of cataclysmic variables (CVs) has been investigated using a B-V, V-I color and variability selection to search for a “missing” population of evolved, low mass transfer types. Two known CVs were observed in the FSVS, GO Com and V394 Lyr, with two periods proposed for V394 Lyr of 2.2 and 5.7 hours. From the sample of CV candidates, a few were identified with follow-up observations to be likely pulsational variables (e.g., RR Lyrae), a W UMa binary, a M dwarf flare star, and a quasar. A sample of known and newly discovered quasars have been investigated for variability. Few quasars (˜10%) are found with intranight and day time-scale variability where as the entire sample shows long month-year time- scale variability at greater amplitudes. A sample of low redshift, low luminosity quasars classified as point sources are found to have correlated variability with changes in the seeing FWHM to ˜0.03 mag/arcsec, bringing into question the variability found in other quasar variability studies.

Huber, Mark Edward

2002-12-01

53

Infrared system for monitoring movement of objects  

DOEpatents

A system for monitoring moving objects, such as the flight of honeybees and other insects, using a pulsed laser light source. This system has a self-powered micro-miniaturized transmitting unit powered, in the preferred embodiment, with an array solar cells. This transmitting unit is attached to the object to be monitored. These solar cells provide current to a storage energy capacitor to produce, for example, five volts for the operation of the transmitter. In the simplest embodiment, the voltage on the capacitor operates a pulse generator to provide a pulsed energizing signal to one or more very small laser diodes. The pulsed light is then received at a receiving base station using substantially standard means which converts the light to an electrical signal for processing in a microprocessor to create the information as to the movement of the object. In the case of a unit for monitoring honeybees and other insects, the transmitting unit weighs less than 50 mg, and has a size no larger than 1.times.3.times.5 millimeters. Also, the preferred embodiment provides for the coding of the light to uniquely identify the particular transmitting unit that is being monitored. A "wake-up" circuit is provided in the preferred embodiment whereby there is no transmission until the voltage on the capacitor has exceeded a pre-set threshold. Various other uses of the motion-detection system are described.

Valentine, Kenneth H. (San Diego, CA); Falter, Diedre D. (Knoxville, TN); Falter, Kelly G. (Knoxville, TN)

1991-01-01

54

Infrared system for monitoring movement of objects  

DOEpatents

A system is described for monitoring moving objects, such as the flight of honeybees and other insects, using a pulsed laser light source. This system has a self-powered micro-miniaturized transmitting unit powered, in the preferred embodiment, with an array of solar cells. This transmitting unit is attached to the object to be monitored. These solar cells provide current to a storage energy capacitor to produce, for example, five volts for the operation of the transmitter. In the simplest embodiment, the voltage on the capacitor operates a pulse generator to provide a pulsed energizing signal to one or more very small laser diodes. The pulsed light is then received at a receiving base station using substantially standard means which converts the light to an electrical signal for processing in a microprocessor to create the information as to the movement of the object. In the case of a unit for monitoring honeybees and other insects, the transmitting unit weighs less than 50 mg, and has a size no larger than 1[times]3[times]5 millimeters. Also, the preferred embodiment provides for the coding of the light to uniquely identify the particular transmitting unit that is being monitored. A wake-up' circuit is provided in the preferred embodiment whereby there is no transmission until the voltage on the capacitor has exceeded a pre-set threshold. Various other uses of the motion-detection system are described. 4 figures.

Valentine, K.H.; Falter, D.D.; Falter, K.G.

1991-04-30

55

THE OPTICAL SPECTRA OF SPITZER 24 mum GALAXIES IN THE COSMIC EVOLUTION SURVEY FIELD. II. FAINT INFRARED SOURCES IN THE zCOSMOS-BRIGHT 10k CATALOG  

SciTech Connect

We have used the zCOSMOS-bright 10k sample to identify 3244 Spitzer/MIPS 24 mum-selected galaxies with 0.06 mJy < S{sub 24{sub m}}u{sub m} approx< 0.50 mJy and I{sub AB} < 22.5, over 1.5 deg{sup 2} of the COSMOS field, and studied different spectral properties, depending on redshift. At 0.2 < z < 0.3, we found that different reddening laws of common use in the literature explain the dust extinction properties of approx80% of our infrared (IR) sources, within the error bars. For up to 16% of objects, instead, the Halpha lambda6563/Hbeta lambda4861 ratios are too high for their IR/UV attenuations, which is probably a consequence of inhomogeneous dust distributions. In only a few of our galaxies at 0.2 < z < 0.3, the IR emission could be mainly produced by dust heated by old rather than young stars. Besides, the line ratios of approx22% of our galaxies suggest that they might be star-formation/nuclear-activity composite systems. At 0.5 < z < 0.7, we estimated galaxy metallicities for 301 galaxies: at least 12% of them are securely below the upper-branch mass-metallicity trend, which is consistent with the local relation. Finally, we performed a combined analysis of the H{sub d}elta equivalent width versus D{sub n} (4000) diagram for 1722 faint and bright 24 mum galaxies at 0.6 < z < 1.0, spanning two decades in mid-IR luminosity. We found that, while secondary bursts of star formation are necessary to explain the position of the most luminous IR galaxies in that diagram, quiescent, exponentially declining star formation histories can well reproduce the spectral properties of approx40% of the less luminous sources. Our results suggest a transition in the possible modes of star formation at total IR luminosities L{sub TIR} approx (3 +- 2) x 10{sup 11} L{sub sun}.

Caputi, K. I.; Lilly, S. J.; Maier, C.; Carollo, C. M. [Institute of Astronomy, Swiss Federal Institute of Technology (ETH), Wolfgang-Pauli-Strasse 27, CH-8093 Zuerich (Switzerland); Aussel, H.; Floc'h, E. Le [CEA/DSM-CNRS, Universite Paris Diderot, DAPNIA/SAp, Orme des Merisiers, 91191 Gif-sur-Yvette (France); Sanders, D. [Institute for Astronomy, University of Hawaii, Honololu, HI (United States); Frayer, D. [Spitzer Science Center, California Institute of Technology, Pasadena, CA (United States); Contini, T. [Laboratoire d'Astrophysique de Toulouse-Tarbes, Universite de Toulouse, 14 avenue Edouard Belin, Toulouse (France); Kneib, J.-P.; Le Fevre, O. [Laboratoire d'Astrophysique de Marseille, 38 rue Frederic Joliot-Curie, Marseille (France); Mainieri, V. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching (Germany); Renzini, A. [Dipartimento di Astronomia, Universita di Padova, Padova (Italy); Scodeggio, M. [INAF-IASF Milano, via E. Bassini 15, 20133 Milan (Italy); Scoville, N. [California Institute of Technology, Pasadena, CA (United States); Zamorani, G.; Bardelli, S.; Bolzonella, M.; Coppa, G. [INAF Osservatorio Astronomico di Bologna, Bologna (Italy); Bongiorno, A., E-mail: kic@roe.ac.u [Max Planck Institut fuer Extraterrestrische Physik, Garching (Germany)

2009-12-20

56

Optical and infrared colors of transneptunian objects observed with HST  

NASA Astrophysics Data System (ADS)

We present optical colors of 72 transneptunian objects (TNOs), and infrared colors of 80 TNOs obtained with the WFPC2 and NICMOS instruments, respectively, on the Hubble Space Telescope (HST). Both optical and infrared colors are available for 32 objects that overlap between the datasets. This dataset adds an especially uniform, consistent and large contribution to the overall sample of colors, particularly in the infrared. The range of our measured colors is consistent with other colors reported in the literature at both optical and infrared wavelengths. We find generally good agreement for objects measured by both us and others; 88.1% have better than 2 sigma agreement. The median absolute magnitude, H V, magnitude of our optical sample is 7.2, modestly smaller (˜0.5 mag) than for previous samples. The median H V in our infrared sample is 6.7. We find no new correlations between color and dynamical properties (semi-major axis, eccentricity, inclination and perihelion). We do find that colors of Classical objects with i < 6° come from a different distribution than either the Resonant or excited populations in the visible at the >99.99% level with a K-S test. The same conclusion is found in the infrared at a slightly lower significance level, 99.72%. Two Haumea collision fragments with strong near infrared ice bands are easily identified with broad HST infrared filters and point to an efficient search strategy for identifying more such objects. We find evidence for variability in (19255) 1999 VK 8, 1999 OE 4, 2000 CE 105, 1998 KG 62 and 1998 WX 31.

Benecchi, S. D.; Noll, K. S.; Stephens, D. C.; Grundy, W. M.; Rawlins, J.

2011-06-01

57

MID-INFRARED SPECTRAL VARIABILITY ATLAS OF YOUNG STELLAR OBJECTS  

SciTech Connect

Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying and interpreting variability on a decadal timescale, here we present a mid-infrared spectral atlas containing observations of 68 low- and intermediate-mass young stellar objects. The atlas consists of 2.5-11.6 {mu}m low-resolution spectra obtained with the ISOPHOT-S instrument on board the Infrared Space Observatory (ISO) between 1996 and 1998, as well as 5.2-14.5 {mu}m low-resolution spectra obtained with the Infrared Spectrograph instrument on board the Spitzer Space Telescope between 2004 and 2007. The observations were retrieved from the ISO and Spitzer archives and were post-processed interactively by our own routines. For those 47 objects where multi-epoch spectra were available, we analyze mid-infrared spectral variability on annual and/or decadal timescales. We identify 37 variable candidate sources. Many stars show wavelength-independent flux changes, possibly due to variable accretion rates. In several systems, all exhibiting 10 {mu}m silicate emission, the variability of the 6-8 {mu}m continuum, and the silicate feature exhibit different amplitudes. A possible explanation is variable shadowing of the silicate-emitting region by an inner disk structure of changing height or extra silicate emission from dust clouds in the disk atmosphere. Our results suggest that mid-infrared variability, in particular, the wavelength-dependent changes, is more ubiquitous than was known before. Interpreting this variability is a new possibility for exploring the structure of the disk and its dynamical processes.

Kospal, A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA, Leiden (Netherlands); Abraham, P.; Kun, M.; Moor, A. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, P.O. Box 67, 1525 Budapest (Hungary); Acosta-Pulido, J. A. [Instituto de Astrofisica de Canarias, Via Lactea s/n, 38200 La Laguna, Tenerife (Spain); Dullemond, C. P. [Institut fuer Theoretische Astrophysik, Zentrum fuer Astronomie der Universitaet Heidelberg, Albert-Ueberle-Str. 2, 69120 Heidelberg (Germany); Henning, Th.; Leinert, Ch. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Turner, N. J., E-mail: akospal@rssd.esa.int [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-08-01

58

An objective methodology for infrared land surface emissivity evaluation  

Microsoft Academic Search

Land surface emissivity (LSE) in the infrared (IR) window region (8–12 ?m) governs the thermal emissions from the Earth's surface. Many LSE databases, retrieved from various satellite instruments, are available for studying climate, Earth-atmosphere interaction, weather, and the environment. The precision (standard deviation) and accuracy (bias) of these databases remain unclear. In this study, we introduce an objective and efficient

Zhenglong Li; Jun Li; Xin Jin; Timothy J. Schmit; Eva E. Borbas; Mitchell D. Goldberg

2010-01-01

59

Near-infrared CO emission in young stellar objects  

Microsoft Academic Search

Near-infrared spectra for 40 young stellar objects were analyzed in order to search for CO overtone emission at 2.3 microns. CO bands were identified in the emission of nine sources, suggesting that about 20 percent of young stellar objects with outflows have CO vibrational band emission. Results show that an accretion disk can produce the observed CO band-head fluxes with

John S. Carr

1989-01-01

60

On the stellar nature of an infrared object, Kodaira 1  

Microsoft Academic Search

Imaging and spectroscopic observations were made for an infrared object (K = 7.0; alpha = 18 hr 12 min 26.54 sec, delta = -12 deg 04 min 12 sec; 1950.0), which was detected in 1983 and listed in Astronomical Almanac as a globular cluster candidate, Kodaira 1. The results of follow-up observations suggest that this object is not a globular

Keiichi Kodaira; Tom Greene; Alan Tokunaga

1995-01-01

61

GTC/OSIRIS SPECTROSCOPIC IDENTIFICATION OF A FAINT L SUBDWARF IN THE UKIRT INFRARED DEEP SKY SURVEY  

SciTech Connect

We present the discovery of an L subdwarf in 234 deg{sup 2} common to the UK InfraRed Telescope (UKIRT) Infrared Deep Sky Survey Large Area Survey Data Release 2 and the Sloan Digital Sky Survey Data Release 3. This is the fifth L subdwarf announced to date, the first one identified in the UKIRT Infrared Deep Sky Survey, and the faintest known. The blue optical and near-infrared colors of ULAS J135058.86+081506.8 and its overall spectra energy distribution are similar to the known mid-L subdwarfs. Low-resolution optical (700-1000 nm) spectroscopy with the Optical System for Imaging and low Resolution Integrated Spectroscopy spectrograph on the 10.4 m Gran Telescopio de Canarias reveals that ULAS J135058.86+081506.8 exhibits a strong K I pressure-broadened line at 770 nm and a red slope longward of 800 nm, features characteristics of L-type dwarfs. From direct comparison with the four known L subdwarfs, we estimate its spectral type to be sdL4-sdL6 and derive a distance in the interval 94-170 pc. We provide a rough estimate of the space density for mid-L subdwarfs of 1.5 x 10{sup -4} pc{sup -3}.

Lodieu, N. [Instituto de AstrofIsica de Canarias, C/VIa Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Osorio, M. R. Zapatero; MartIn, E. L.; Solano, E.; Aberasturi, M. [Centro de AstrobiologIa (CSIC/INTA), 28850 Torrejon de Ardoz, Madrid (Spain)], E-mail: nlodieu@iac.es

2010-01-10

62

Faint blue objects at high galactic latitude. IV - Palomar Schmidt fields centered on selected areas 55 and 94  

NASA Astrophysics Data System (ADS)

Color classes, subclasses, and approximate positions and magnitudes are ascertained for UV-excess objects that have been selected from Palomar Schmidt fields centered on Selected Areas 55 and 94. The method of selection uses the relative colors of the halo subdwarfs. The three-color imagery of the Tonantzintla technique also permits a mnemonic subclassification.

Huang, K.-L.; Usher, P. D.

1984-11-01

63

Preliminary analysis of an ultraviolet Hubble Space Telescope faint object camera image of the center of M31  

NASA Technical Reports Server (NTRS)

A 5161 s exposure was taken with the FOC on the central 44 arcsec of M31, through a filter centered at 1750 A. Much of the light is redleak from visible wavelengths, but nearly half of it is genuine UV. The image shows the same central peak found earlier by Stratoscope, with a somewhat steeper dropoff outside that peak. More than 100 individual objects are seen, some pointlike and some slightly extended. We identify them as post-asymptotic giant branch stars, some of them surrounded by a contribution from their accompanying planetary nebulae. These objects contribute almost a fifth of the total UV light, but fall far short of accounting for all of it. We suggest that the remainder may result from the corresponding evolutionary tracks in a population more metal-rich than solar.

King, I. R.; Deharveng, J. M.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.; Crane, P.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

1992-01-01

64

Near-Infrared Properties of Faint X-Ray Sources from NICMOS Imaging in the Chandra Deep Fields  

Microsoft Academic Search

We measure the near-infrared properties of 42 X-ray-detected sources from the Chandra Deep Fields North and South, the majority of which lie within the NICMOS Hubble Deep Field-North and Ultra Deep Field. We detect all 42 Chandra sources with NICMOS, with 95% brighter than H160=24.5. We find that X-ray sources are most often in the brightest and most massive galaxies.

James W. Colbert; Harry I. Teplitz; Lin Yan; Matthew A. Malkan; Patrick J. McCarthy

2005-01-01

65

Near-Infrared Properties of Faint X-rays Sources from NICMOS Imaging in the Chandra Deep Fields  

Microsoft Academic Search

We measure the near-infrared properties of 42 X-ray detected sources from the\\u000aChandra Deep Fields North and South, the majority of which lie within the\\u000aNICMOS Hubble Deep Field North and Ultra Deep Field. We detect all 42 Chandra\\u000asources with NICMOS, with 95% brighter than H = 24.5. We find that X-ray\\u000asources are most often in the brightest

James W. Colbert; Harry I. Teplitz; Lin Yan; Matthew A. Malkan; Patrick J. McCarthy

2004-01-01

66

Near-infrared observations of comet-asteroid transition objects  

NASA Astrophysics Data System (ADS)

The primary objective of this research is to characterize the surface composition of five comet-asteroid transition objects via near-infrared spectroscopy. The five targets include two asteroids with Tisserand invariants lower than 3.0 (1373 Cincinnati and 2906 Caltech), one asteroid that is likely an extinct comet (944 Hidalgo), one intermittent activity comet (162P/Siding Spring), and one nearly dormant comet (28P/Neujmin1). Previous research regarding cometary end states and dynamical and physical properties of comets and asteroids provides the foundation for this work. Focusing primarily on the 1-2.5 ?m spectral region of the five target objects, this project specifically searches for mineral species such as olivine, pyroxene, hydrated silicates, and organics. Comparisons are made with comets, main belt asteroids, and Trojan asteroids. All our targets have near-infrared spectra with varying "red" slopes from S'=1.7 to 5.3. Slopes in this range are characteristic of both primitive asteroids and comets. Three of our objects, 944 Hidalgo, 162P/Siding Spring, 28P/Neujmin 1, showed relatively featureless near-infrared spectra. The two objects dynamically most likely to be of asteroidal origin, 1373 Cincinnati and 2906 Caltech, both displayed features in the 0.8 to 2.5 micron range, not present in any of our other targets or the comparison cometary nuclei. Spectra of 944 Hidalgo were acquired at several rotational phases and clear rotational variations were found. Hints of spectral variability were also observed in 28P/ Neujmin 1 and 162P/Siding Spring. Neither 1373 nor 2906 were examined for rotational variability. Based on our results, we believe that 1373 Cincinnatti and 2906 Caltech are not cometary. The spectral range of our targets and cometary spectra in the near-infrared is the same as that of Trojan asteroids. Recommendations for future investigation are suggested.

Ziffer, Julie Elaine

67

Infrared Spectra of Comet-Asteroid Transition Object 944 Hidalgo  

NASA Astrophysics Data System (ADS)

Asteroid 944 Hidalgo is suspected of being an extinct comet. Understanding the origin of this enigmatic object is relevant to several areas of planetary astronomy, and the study of its surface composition may be diagnostic of its origin. Silicates have been detected in active comets, and on Jupiter Trojans. Our team investigated Hidalgo in the 8-30 micron range to determine the mineral composition and presence of surface silicates. We chose this wavelength region because it is most diagnostic for the detection of silicates. We applied to use NASA's Spitzer Space Telescope as Hidalgo is too faint at these wavelengths for ground- based telescopes. Once the data were collected, the continuum was modeled and subtracted from the raw spectra. The result is a plot of emissivity versus wavelength that shows clear emission features from 8-13 microns, and around 20 microns; both of which have been identified with silicates. Our spectrum is compared with those of Jupiter Trojans, which are believed to be related to comets, and comet Hale-Bopp. With the project complete, we have demonstrated the presence of silicate emissions in Hidalgo and strong similarity with spectra of Jupiter Trojans and of active comets. These results argue in favor of Hidalgo having formed further from the Sun than main belt asteroids. We conclude that our findings are consistent, but not definitive, with Hidalgo being of cometary origin. Understanding the composition of this body and others like it is important for determining the origin of Earth's water.

Hargrove, K.; Campins, H.; Kelley, M.; Fernandez, Y.; Ziffer, J.; Licandro, J.; Emery, J.; Cruikshank, D.; Hergenrother, C.; Pinilla-Alonso, N.; Clautice, D.

2008-05-01

68

The infrared overluminosity of young, ultracool substellar objects  

NASA Astrophysics Data System (ADS)

Most young, ultracool substellar objects with spectral types later than M9 show very red mid-infrared colors up to 24~micron, significantly redder than expected for their optical and near-infrared spectral classifications. These objects have estimated ages and masses in the intervals 20-300 Myr and 12-35 times the mass of Jupiter, respectively. According to optical data, their atmospheres have low gravity and are rather cool with characteristic effective temperatures between 1300 and 2400 K, rather close to the temperatures of close-in giant planets around solar-type stars. We focus on the particular case of G196-3B, an L3-type substellar companion orbiting a young low-mass star. We discuss various physical scenarios to account for its reddish nature and conclude that a low-gravity atmosphere with enshrouded upper atmospheric layers and/or a warm dusty disk/envelope provides the most likely explanations.

Zapatero Osorio, M. R.; Rebolo, R.; Bihain, G.; Bejar, V. J. S.; Caballero, J. A.; Alvarez, C.

2011-11-01

69

A study of ultraviolet absorption lines through the complete Galactic halo by the analysis of HST faint object spectrograph spectra of active Galactic nuclei, 1  

NASA Technical Reports Server (NTRS)

The ultraviolet (1150 - 2850 A) spectra of a number of active galactic nuclei (AGNs) observed with the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) have been used to study the properties of the Galactic halo. The objects that served as probes are 3C 273, PKS 0454-220, Pg 1211+143, CSO 251, Ton 951, and PG 1351+640. The equivalent widths of certain interstellar ions have been measured, with special attention paid to the C IV/C II and Si IV/Si II ratios. These ratios have been intercompared, and the highest values are found in the direction of 3C 273, where C IV/C II = 1.2 and Si IV/Si II greater than 1. These high ratios may be due to a nearby supernova remnant, rather than to ionized gas higher up in the Galactic halo. Our data give some support to the notion that QSO metal-line systems may arise from intervening galaxies which contain high supernova rates, galactic fountains, and turbulent mixing layers.

Burks, Geoffrey S.; Bartko, Frank; Shull, J. Michael; Stocke, John T.; Sachs, Elise R.; Burbidge, E. Margaret; Cohen, Ross D.; Junkkarinen, Vesa T.; Harms, Richard J.; Massa, Derck

1994-01-01

70

INFRARED SPECTRAL OBSERVATION OF EIGHT BL LAC OBJECTS FROM THE SPITZER INFRARED SPECTROGRAPH  

SciTech Connect

The Spitzer Infrared Spectrograph (IRS) low-resolution spectra for eight BL Lac objects are presented in this paper. It can be seen that the infrared spectrum of S5 0716+714 shows in the IRS region many emission features that would be from a nearby galaxy. It is also shown that, except for the silicate absorptions around 10 {mu}m for some sources, emission lines in the infrared spectra for the other seven BL Lac objects are indeed very weak or absent. In addition, ignoring the silicate feature, all spectra can be well fitted by a power-law distribution indicative of the emission mechanism of the synchrotron radiation for these BL Lac objects in the IRS region.

Chen, P. S.; Shan, H. G., E-mail: iraspsc@yahoo.com.cn [National Astronomical Observatories/Yunnan Observatory and Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011 (China)

2011-05-01

71

On the stellar nature of an infrared object, Kodaira 1  

NASA Astrophysics Data System (ADS)

Imaging and spectroscopic observations were made for an infrared object (K = 7.0; alpha = 18 hr 12 min 26.54 sec, delta = -12 deg 04 min 12 sec; 1950.0), which was detected in 1983 and listed in Astronomical Almanac as a globular cluster candidate, Kodaira 1. The results of follow-up observations suggest that this object is not a globular cluster core, as was previously suspected, but is most probably a star of M5-8 III heavily reddened by E(V - K) approximately equal to 7-8.

Kodaira, Keiichi; Greene, Tom; Tokunaga, Alan

1995-02-01

72

The AKARI Far-Infrared Surveyor young stellar object catalog  

NASA Astrophysics Data System (ADS)

We demonstrate the use of the AKARI all-sky survey photometric data in the study of galactic star formation. Our aim was to select young stellar objects (YSOs) in the AKARI Far-Infrared Surveyor (FIS) Bright Source Catalogue. We used AKARI/FIS and Wide-field Infrared Survey Explorer (WISE) data to derive mid- and far-infrared colors of YSOs. Classification schemes based on quadratic discriminant analysis (QDA) have been given for YSOs and the training catalog for QDA was the whole-sky selection of previously known YSOs (i.e., listed in the SIMBAD database). A new catalog of AKARI FIS YSO candidates including 44001 sources has been prepared; the reliability of the classification is over 90%, as tested in comparison to known YSOs. As much as 76% of our YSO candidates are from previously uncatalogued types. The vast majority of these sources are Class I and II types according to the Lada classification. The distribution of AKARI FIS YSOs is well correlated with that of the galactic ISM; local over-densities were found on infrared loops and towards the cold clumps detected by Planck.

Tóth, L. Viktor; Marton, Gábor; Zahorecz, Sarolta; Balázs, Lajos G.; Ueno, Munetaka; Tamura, Motohide; Kawamura, Akiko; Kiss, Zoltán T.; Kitamura, Yoshimi

2014-02-01

73

INFRARED SPECTROSCOPY OF INTERMEDIATE-MASS YOUNG STELLAR OBJECTS  

SciTech Connect

In this paper, we present Spitzer Infrared Spectrograph spectroscopy for 14 intermediate-mass young stellar objects (YSOs). We use Spitzer spectroscopy to investigate the physical properties of these sources and their environments. Our sample can be divided into two types of objects: young isolated, embedded objects with spectra that are dominated by ice and silicate absorption bands, and more evolved objects that are dominated by extended emission from polycyclic aromatic hydrocarbons (PAHs) and pure H{sub 2} rotational lines. We are able to constrain the illuminating FUV fields by classifying the PAH bands below 9 {mu}m. For most of the sources we are able to detect several atomic fine structure lines. In particular, the [Ne II] line appearing in two regions could originate from unresolved photodissociation regions or J-shocks. We relate the identified spectral features to observations obtained from NIR through submillimeter imaging. The spatial extent of several H{sub 2} and PAH bands is matched with morphologies identified in previous Infrared Array Camera observations. This also allows us to distinguish between the different H{sub 2} excitation mechanisms. In addition, we calculate the optical extinction from the silicate bands and use this to constrain the spectral energy distribution fit, allowing us to estimate the masses of these YSOs.

Pitann, Jan; Bouwman, Jeroen; Krause, Oliver; Henning, Thomas [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Hennemann, Martin [Laboratoire AIM, CEA/IRFU-CNRS-Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif-sur-Yvette (France); Birkmann, Stephan, E-mail: pitann@mpia.de [ESA/ESTEC, Keplerlaan 1, Postbus 299, 2200 AG Noordwijk (Netherlands)

2011-12-10

74

A fuzzy automated object classification by infrared laser camera  

NASA Astrophysics Data System (ADS)

Home security in night is very important, and the system that watches a person's movements is useful in the security. This paper describes a classification system of adult, child and the other object from distance distribution measured by an infrared laser camera. This camera radiates near infrared waves and receives reflected ones. Then, it converts the time of flight into distance distribution. Our method consists of 4 steps. First, we do background subtraction and noise rejection in the distance distribution. Second, we do fuzzy clustering in the distance distribution, and form several clusters. Third, we extract features such as the height, thickness, aspect ratio, area ratio of the cluster. Then, we make fuzzy if-then rules from knowledge of adult, child and the other object so as to classify the cluster to one of adult, child and the other object. Here, we made the fuzzy membership function with respect to each features. Finally, we classify the clusters to one with the highest fuzzy degree among adult, child and the other object. In our experiment, we set up the camera in room and tested three cases. The method successfully classified them in real time processing.

Kanazawa, Seigo; Taniguchi, Kazuhiko; Asari, Kazunari; Kuramoto, Kei; Kobashi, Syoji; Hata, Yutaka

2011-05-01

75

SearchCal: a Virtual Observatory tool for searching calibrators in optical long-baseline interferometry. II. The faint-object case  

NASA Astrophysics Data System (ADS)

Context. In long-baseline interferometry, images or astrophysical parameters are obtained from the raw fringe contrast after a careful calibration process. We have already developed the software (SearchCal) to select suitable bright calibration stars (V ? 10; K ? 5.0) for obtaining the ultimate precision of current interferometric instruments like the VLTI. With the expected gain in sensitivity of AMBER and PRIMA on the VLTI, the need for fainter calibrators should now be adressed. Aims: We present a new version of SearchCal dedicated to the creation of an evolving catalog of stars suitable as calibrators with K magnitude >5 around the scientific target. Methods: Star catalogs available at the CDS are searched via web requests and provide the useful astrometric and photometric informations for selecting calibrators. The missing photometries are computed with an accuracy of about 0.1 mag. The stellar angular diameter is estimated with a precision of about 10% through newly determined surface-brightness versus color-index relations based on the I, J, H and K magnitudes. For each star the squared visibility is computed taking into account the central wavelength and the maximum baseline of the predicted observations. Results: The version of SearchCal for faint objects that allows to find calibrators for interferometric observations up to K ~ 15 is available as a web service at the address: http://www.jmmc.fr/searchcal

Bonneau, D.; Delfosse, X.; Mourard, D.; Lafrasse, S.; Mella, G.; Cetre, S.; Clausse, J.-M.; Zins, G.

2011-11-01

76

THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE DATA: PANCHROMATIC FAINT OBJECT COUNTS FOR 0.2-2 {mu}m WAVELENGTH  

SciTech Connect

We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Release Science (ERS) observations in the Great Observatories Origins Deep Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, drizzled mosaics in the UV filters F225W, F275W, and F336W, as well as in the near-IR filters F098M (Y{sub s} ), F125W (J), and F160W (H) with 1-2 HST orbits per filter. Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South mosaics in the BViz filters, these panchromatic 10-band ERS data cover 40-50 arcmin{sup 2} at 0.2-1.7 {mu}m in wavelength at 0.''07-0.''15 FWHM resolution and 0.''090 Multidrizzled pixels to depths of AB {approx_equal} 26.0-27.0 mag (5{sigma}) for point sources, and AB {approx_equal} 25.5-26.5 mag for compact galaxies. In this paper, we describe (1) the scientific rationale, and the data taking plus reduction procedures of the panchromatic 10-band ERS mosaics, (2) the procedure of generating object catalogs across the 10 different ERS filters, and the specific star-galaxy separation techniques used, and (3) the reliability and completeness of the object catalogs from the WFC3 ERS mosaics. The excellent 0.''07-0.''15 FWHM resolution of HST/WFC3 and ACS makes star-galaxy separation straightforward over a factor of 10 in wavelength to AB {approx_equal} 25-26 mag from the UV to the near-IR, respectively. Our main results are: (1) proper motion of faint ERS stars is detected over 6 years at 3.06 {+-} 0.66 mas year{sup -1} (4.6{sigma}), consistent with Galactic structure models; (2) both the Galactic star counts and the galaxy counts show mild but significant trends of decreasing count slopes from the mid-UV to the near-IR over a factor of 10 in wavelength; (3) combining the 10-band ERS counts with the panchromatic Galaxy and Mass Assembly survey counts at the bright end (10 mag {approx}< AB {approx}< 20 mag) and the Hubble Ultra Deep Field counts in the BVizY{sub s}JH filters at the faint end (24 mag {approx}< AB {approx}< 30 mag) yields galaxy counts that are well measured over the entire flux range 10 mag {approx}< AB {approx}< 30 mag for 0.2-2 {mu}m in wavelength; (4) simple luminosity+density evolution models can fit the galaxy counts over this entire flux range. However, no single model can explain the counts over this entire flux range in all 10 filters simultaneously. More sophisticated models of galaxy assembly are needed to reproduce the overall constraints provided by the current panchromatic galaxy counts for 10 mag {approx}< AB {approx}< 30 mag over a factor of 10 in wavelength.

Windhorst, Rogier A.; Cohen, Seth H.; Mechtley, Matt; Rutkowski, Michael J. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States); Hathi, Nimish P. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); McCarthy, Patrick J.; Seibert, Mark [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101-1292 (United States); Ryan, Russell E. Jr [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Yan Haojing [Center for Cosmology and AstroParticle Physics, The Ohio State University, Columbus, OH 43210 (United States); Baldry, Ivan K. [Astrophysics Research Institute, Liverpool John Moores University, Birkenhead CH41 1LD (United Kingdom); Driver, Simon P.; Hill, David T.; Kelvin, Lee S.; Robotham, Aaron S. G. [School of Physics and Astronomy, University of St Andrews, Fife KY16 9SS (United Kingdom); Frogel, Jay A. [Association of Universities for Research in Astronomy, Washington, DC 20005 (United States); Koekemoer, Anton M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); O'Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Straughn, Amber N. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Tuffs, Richard J. [Max Planck Institute for Nuclear Physics (MPIK), Saupfercheckweg 1, D-69117 Heidelberg (Germany); Balick, Bruce, E-mail: Rogier.Windhorst@asu.edu [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States)

2011-04-01

77

Optical-faint, Far-infrared-bright Herschel Sources in the CANDELS Fields: Ultra-luminous Infrared Galaxies at z > 1 and the Effect of Source Blending  

NASA Astrophysics Data System (ADS)

The Herschel very wide field surveys have charted hundreds of square degrees in multiple far-IR (FIR) bands. While the Sloan Digital Sky Survey (SDSS) is currently the best resource for optical counterpart identifications over such wide areas, it does not detect a large number of Herschel FIR sources and leaves their nature undetermined. As a test case, we studied seven "SDSS-invisible," very bright 250 ?m sources (S 250 > 55 mJy) in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields where we have a rich multi-wavelength data set. We took a new approach to decompose the FIR sources, using the near-IR or the optical images directly for position priors. This is an improvement over the previous decomposition efforts where the priors are from mid-IR data that still suffer from the problem of source blending. We found that in most cases the single Herschel sources are made of multiple components that are not necessarily at the same redshifts. Our decomposition succeeded in identifying and extracting their major contributors. We show that these are all ultra-luminous infrared galaxies at z ~ 1-2 whose high L IR is mainly due to dust-obscured star formation. Most of them would not be selected as submillimeter galaxies. They all have complicated morphologies indicative of mergers or violent instability, and their stellar populations are heterogeneous in terms of stellar masses, ages, and formation histories. Their current ultra-luminous infrared galaxy phases are of various degrees of importance in their stellar mass assembly. Our practice provides a promising starting point for developing an automatic routine to reliably study bright Herschel sources.

Yan, Haojing; Stefanon, Mauro; Ma, Zhiyuan; Willner, S. P.; Somerville, Rachel; Ashby, Matthew L. N.; Davé, Romeel; Pérez-González, Pablo G.; Cava, Antonio; Wiklind, Tommy; Kocevski, Dale; Rafelski, Marc; Kartaltepe, Jeyhan; Cooray, Asantha; Koekemoer, Anton M.; Grogin, Norman A.

2014-07-01

78

Hubble Space Telescope/Faint Object Spectrograph Spectroscopy of Spatially Resolved Narrow-Line Regions in the Seyfert 2 Galaxies NGC 2110 and NGC 5929  

NASA Astrophysics Data System (ADS)

We present the results of UV and optical Hubble Space Telescope/Faint Object Spectrograph spectroscopy of bright, extranuclear regions of line emission in the Seyfert galaxies NGC 2110 and NGC 5929. We have obtained spectra of the brightest region of the ``nuclear jet'' of NGC 2110 (75 pc from the nucleus) and of the southwest emission-line cloud of NGC 5929 (90 pc from the nucleus), in the G130H (1090-1605 Å), G190H (1570-2310 Å), G400H (3235-4780 Å), and G570H (4570-6820 Å) configurations. The observed line ratios are compared with the predictions of the two component (matter- and ionization-bounded, MB-IB), central source photoionization models of Binette, Wilson, & Storchi-Bergmann and of the fast, photoionizing (``autoionizing'') shock models of Dopita & Sutherland. In both objects, the significant reddening inferred from the Balmer line ratios and/or its uncertainty limit the utility of the ultraviolet carbon lines C IV ?1549 and C III] ?1909 for discrimination between the central source and shock-induced photoionization mechanisms. In NGC 2110, shock+precursor models with a shock velocity of ~=400 km s-1 provide a better match to the data than the MB-IB models. However, given the simplifying assumptions made in the latter models, photoionization by a central source cannot be ruled out. We investigate whether photoionizing shocks in the emission-line region of NGC 2110 can power the extended, soft X-ray emission north of the nucleus and find that shock velocities higher than 500 km s-1 are required. In NGC 5929, the MB-IB models have problems reproducing the strengths of the neon lines, while shock+precursor models with a velocity ~=300 km s-1 provide a good match to the data. For both galaxies, the emission-line powers and volumes of the ionized gas inferred from observations imply that both the preshock density (n0) and magnetic parameter (B0/n1/20) must be relatively high (n0>10 cm-3 B0/n1/20~=4 ?G cm3/2) for the photoionizing shock models to be viable. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Ferruit, Pierre; Wilson, Andrew S.; Whittle, Mark; Simpson, Chris; Mulchaey, John S.; Ferland, Gary J.

1999-09-01

79

A 21 Centimeter Absorber Identified with a Spiral Galaxy: Hubble Space Telescope Faint Object Spectrograph and Wide-Field Camera Observations of 3CR 196  

NASA Technical Reports Server (NTRS)

We present imaging and spectroscopy of the quasar 3CR 196 (z(sub e) = 0.871), which has 21 cm and optical absorption at z(sub a) = 0.437. We observed the region of Ly alpha absorption in 3CR 196 at z(sub a) = 0.437 with the Faint Object Spectrograph on the Hubble Space Telescope. This region of the spectrum is complicated because of the presence of a Lyman limit and strong lines from a z(sub a) approx. z(sub e) system. We conclude that there is Ly alpha absorption with an H I column density greater than 2.7 x 10(exp 19) cm(exp -2) and most probably 1.5 x 10(exp 20) cm(exp -2). Based on the existence of the high H I column density along both the optical and radio lines of sight, separated by more than 15 kpc, we conclude that the Ly alpha absorption must arise in a system comparable in size to the gaseous disks of spiral galaxies. A barred spiral galaxy, previously reported as a diffuse object in the recent work of Boisse and Boulade, can be seen near the quasar in an image taken at 0.1 resolution with the Wide Field Planetary Camera 2 on the HST. If this galaxy is at the absorption redshift, the luminosity is approximately L(sub *) and any H I disk should extend in front of the optical quasar and radio lobes of 3CR 196, giving rise to both the Ly alpha and 21 cm absorption. In the z(sub a) approx. z(sub e) system we detect Lyman lines and the Lyman limit, as well as high ion absorption lines of C III, N V, S VI, and O VI. This absorption probably only partially covers the emission-line region. The ionization parameter is approximately 0.1. Conditions in this region may be similar to those in broad absorption line QSOs.

Cohen, Ross D.; Beaver, E. A.; Diplas, Athanassios; Junkkarinen, Vesa T.; Barlow, Thomas A.; Lyons, Ronald W.

1996-01-01

80

Objective quality evaluation of visible and infrared color fusion image  

NASA Astrophysics Data System (ADS)

An evaluation for objectively assessing the quality of visible and infrared color fusion image is proposed. On the basis of the consideration that human perception is most sensitive to color, sharpness, and contrast when assessing the quality of color image, we propose four objective metrics: image sharpness metric (ISM), image contrast metric (ICM), color colorfulness metric (CCM), and color naturalness metric (CNM). The ISM is evaluated by image gradient information. The ICM is defined based on both gray and color histogram characteristics. A color chroma metric, as well as a color variety metric based on a color difference gradient, is proposed, respectively, to define the CCM. The CNM is defined by measuring the color distribution's similarity between the fusion image and nature image, which are of the same scene. All the color attributions are computed in the CIELAB color space. Experimental results show that the proposed objective metrics are meaningful and effective on color fusion image evaluation because they correspond well to subjective evaluation.

Yuan, Yihui; Zhang, Junju; Chang, Benkang; Han, Yiyong

2011-03-01

81

Alignment and Performance of the Infrared Multi-Object Spectrometer  

NASA Technical Reports Server (NTRS)

The Infrared Multi-Object Spectrometer (IRMOS) is a principle investigator class instrument for the Kitt Peak National Observatory 4 and 2.1 meter telescopes. IRMOS is a near-IR (0.8 - 2.5 micron) spectrometer with low-to mid-resolving power (R = 300 - 3000). IRMOS produces simultaneous spectra of approximately 100 objects in its 2.8 x 2.0 arc-min field of view (4 m telescope) using a commercial Micro Electro-Mechanical Systems (MEMS) micro-mirror array (MMA) from Texas Instruments. The IRMOS optical design consists of two imaging subsystems. The focal reducer images the focal plane of the telescope onto the MMA field stop, and the spectrograph images the MMA onto the detector. We describe ambient breadboard subsystem alignment and imaging performance of each stage independently, and ambient imaging performance of the fully assembled instrument. Interferometric measurements of subsystem wavefront error serve as a qualitative alignment guide, and are accomplished using a commercial, modified Twyman-Green laser unequal path interferometer. Image testing provides verification of the optomechanical alignment method and a measurement of near-angle scattered light due to mirror small-scale surface error. Image testing is performed at multiple field points. A mercury-argon pencil lamp provides a spectral line at 546.1 nanometers, a blackbody source provides a line at 1550 nanometers, and a CCD camera and IR camera are used as detectors. We use commercial optical modeling software to predict the point-spread function and its effect on instrument slit transmission and resolution. Our breadboard and instrument level test results validate this prediction. We conclude with an instrument performance prediction for cryogenic operation and first light in late 2003.

Connelly, Joseph A.; Ohl, Raymond G.; Mentzell, J. Eric; Madison, Timothy J.; Hylan, Jason E.; Mink, Ronald G.; Saha, Timo T.; Tveekrem, June L.; Sparr, Leroy M.; Chambers, V. John; Fitzgerald, Danetter; Greenhouse, Matthew A.; MacKenty, John W.

2004-01-01

82

Quasi-Stellar Objects, Ultraluminous Infrared Galaxies, and Mergers  

Microsoft Academic Search

We test the hypothesis that QSOs are formed via strong tidal interactions or mergers, initially going through an ultraluminous infrared phase. Our approach is to look for traces of this phase in the host galaxies of QSOs. We select a sample of low-redshift bona fide QSOs that may be in a transitionary stage between ultraluminous infrared galaxies (ULIGs) and QSOs.

Gabriela Canalizo; Alan Stockton

2001-01-01

83

Subarcsecond Mid-Infrared Observations of Young Stellar Objects  

NASA Astrophysics Data System (ADS)

To study the formation of stars and possible planetary systems, we developed a scanned linear array for astronomical imaging at a wavelength of 10 ?m. This dissertation presents observations of the young stellar objects LkH? 101 and AFGL 2591 using the scanned array at the 3 m Shane Telescope. These observations are diffraction-limited; the point-spread function of the linear array imager at the Shane Telescope has a width (FWHM) of ~0.75''. Deconvolution of the point-spread function gives a spatial resolution of ~0.35''. We find that both LkH? 101 and AFGL 2591 are unresolved and place upper limits of 0.35'' on their 10 ?m diameters, which corresponds to diameters smaller than 270 AU for LkH? 101 and 700 AU for AFGL 2591. For both LkH? 101 and AFGL 2591, our upper limits on their sizes indicate that the sources must have high absorption efficiencies near ?=10/ ?m to emit the measured radiation from within a region smaller than our upper limit. If the emission is optically thin emission from dust grains, then our observations indicate that the grains are large compared to the sizes expected for grains in the interstellar medium. Radio observations show that a roughly uniform ionized stellar wind emanates from LkH? 101; this suggests that the unresolved 10 ?m emission arises from an optically thin r-2 distribution of dust grains flowing in the wind. Such a distribution is consistent with our upper limit on the source size and the spectral energy distribution if the grains are graphite or glassy carbon and have radii confined to the range 0.3~infrared emission is optically thin emission from silicate grains in a disk, as the spectrum possibly indicates, then the grains must have radii a~>1.0/ ?m, assuming T=460 K and i=50o for the disk. This lower limit on grain size assumes that grains do not overlap each other in projection onto the surface of the disk.

Danen, Robert Martin

84

Visible and Near Infrared colors of Trans-neptunian Objects  

Microsoft Academic Search

We present the latest results of the Meudon Multicolor survey (2MS). This survey aimed at characterizing the colors properties and trends of Centaurs and Trans-Neptunian Objects. We report IJHK photometry of objects obtained with CFHT-IR at the Canada-France-Hawaii 3.6-m Telescope (CFHT, Hawaii), JHK photometry with INGRID at the William Hershel 4.2-m Telescope (WHT, La Palma), and BVRI photometry with OIG

Alain Doressoundiram; N. Peixinho

2007-01-01

85

Herbig-Haro Objects and Mid-infrared Outflows in the Vela C Molecular Cloud  

NASA Astrophysics Data System (ADS)

We have performed a deep [S II] ??6717/6731 wide field Herbig-Haro (HH) object survey toward the Vela C molecular cloud with a sky coverage of about 2 deg2. In total, 18 new HH objects, HH 1090-1107, are discovered and the two previously known HH objects, HH 73-74, are also detected in our [S II] images. We also present an investigation of mid-infrared outflows in the Vela C molecular cloud using the Wide-field Infrared Survey Explorer images taken from AllWISE data release. Using the method suggested by Zhang & Wang, 11 extended green objects (EGOs) are identified to be the mid-infrared outflows, including 6 new mid-infrared outflows that have not been detected previously at other wavelengths and 5 mid-infrared counterparts of the HH objects detected in this work. Using the AllWISE Source Catalog and the source classification scheme suggested by Koenig et al., we have identified 56 young stellar object (YSO) candidates in the Vela C molecular cloud. The possible driving sources of the HH objects and EGOs are discussed based on the morphology of HH objects and EGOs and the locations of HH objects, EGOs and YSO candidates. Finally we associate 12 HH objects and 5 EGOs with 10 YSOs and YSO candidates. The median length of the outflows in Vela C is 0.35 pc and the outflows seem to be oriented randomly.

Zhang, Miaomiao; Wang, Hongchi; Henning, Thomas

2014-08-01

86

Infrared detection, recognition and identification of handheld objects  

NASA Astrophysics Data System (ADS)

A main criterion for comparison and selection of thermal imagers for military applications is their nominal range performance. This nominal range performance is calculated for a defined task and standardized target and environmental conditions. The only standardization available to date is STANAG 4347. The target defined there is based on a main battle tank in front view. Because of modified military requirements, this target is no longer up-to-date. Today, different topics of interest are of interest, especially differentiation between friend and foe and identification of humans. There is no direct way to differentiate between friend and foe in asymmetric scenarios, but one clue can be that someone is carrying a weapon. This clue can be transformed in the observer tasks detection: a person is carrying or is not carrying an object, recognition: the object is a long / medium / short range weapon or civil equipment and identification: the object can be named (e. g. AK-47, M-4, G36, RPG7, Axe, Shovel etc.). These tasks can be assessed experimentally and from the results of such an assessment, a standard target for handheld objects may be derived. For a first assessment, a human carrying 13 different handheld objects in front of his chest was recorded at four different ranges with an IR-dual-band camera. From the recorded data, a perception experiment was prepared. It was conducted with 17 observers in a 13-alternative forced choice, unlimited observation time arrangement. The results of the test together with Minimum Temperature Difference Perceived measurements of the camera and temperature difference and critical dimension derived from the recorded imagery allowed defining a first standard target according to the above tasks. This standard target consist of 2.5 / 3.5 / 5 DRI line pairs on target, 0.24 m critical size and 1 K temperature difference. The values are preliminary and have to be refined in the future. Necessary are different aspect angles, different carriage and movement.

Adomeit, Uwe

2012-10-01

87

Mid-infrared observations of young stellar objects in the vicinity of sigma Orionis  

Microsoft Academic Search

We present new mid-infrared observations of objects in the vicinity of the\\u000aO-star sigma Orionis, obtained with TIMMI-2 at ESO. By constraining their near-\\u000aand mid-infrared spectral energy distributions, we established the nature of\\u000apreviously known IRAS sources and identified new mid-infrared sources as young\\u000astellar objects with circumstellar disks, likely massive members of the sigma\\u000aOri cluster. For two

Joana M. Oliveira; Jacco Th. van Loon

2004-01-01

88

NEAR-INFRARED PROPERTIES OF THE X-RAY-EMITTING YOUNG STELLAR OBJECTS IN THE CARINA NEBULA  

SciTech Connect

The Great Nebula in Carina (NGC 3372) is the best target to study in detail the process of violent massive star formation and the resulting feedback effects of cloud dispersal and triggered star formation. While the population of massive stars is rather well studied, the associated low-mass stellar population was largely unknown up to now. The near-infrared study in this paper builds on the results of the Chandra Carina Complex Project, that detected 14,368 X-ray sources in the 1.4 deg{sup 2} survey region, an automatic source classification study that classified 10,714 of these X-ray sources as very likely young stars in Carina, and an analysis of the clustering properties of the X-ray-selected Carina members. In order to determine physical properties of the X-ray-selected stars, most of which were previously unstudied, we used HAWK-I at the ESO Very Large Telescope to conduct a very deep near-IR survey with subarcsecond angular resolution, covering an area of about 1280 arcmin{sup 2}. The HAWK-I images reveal more than 600,000 individual infrared sources, whereby objects as faint as J {approx} 23, H {approx} 22, and K{sub s} {approx} 21 are detected at signal-to-noise ratio (S/N) {>=}3. While less than half of the Chandra X-ray sources have counterparts in the Two Micron All Sky Survey catalog, the {approx}5 mag deeper HAWK-I data reveal infrared counterparts to 6636 (=88.8%) of the 7472 Chandra X-ray sources in the HAWK-I field. We analyze near-infrared color-color and color-magnitude diagrams to derive information about the extinctions, infrared excesses (as tracers for circumstellar disks), ages, and masses of the X-ray-selected objects. The near-infrared properties agree well with the results of the automatic X-ray source classification, showing that the remaining contamination in the X-ray-selected sample of Carina members is very low ({approx}<7%). The shape of the K-band luminosity function of the X-ray-selected Carina members agrees well with that derived for the Orion Nebula Cluster, suggesting that, down to the X-ray detection limit around 0.5-1 M{sub sun}, the shape of the initial mass function (IMF) in Carina is consistent with that in Orion (and thus the field IMF). The fraction of stars with near-infrared excesses is rather small, {approx}<10%, but shows considerable variations between individual parts of the complex. The distribution of extinctions for the diskless stars ranges from {approx}1.6 mag to {approx}6.2 mag (central 80th percentile), clearly showing a considerable range of differential extinction between individual stars in the complex.

Preibisch, Thomas [Universitaets-Sternwarte Muenchen, Ludwig-Maximilians-Universitaet, Scheinerstr. 1, 81679 Muenchen (Germany); Hodgkin, Simon; Irwin, Mike; Lewis, James R. [Cambridge Astronomical Survey Unit, Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); King, Robert R. [Astrophysics Group, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QL (United Kingdom); McCaughrean, Mark J. [European Space Agency, Research and Scientific Support Department, ESTEC, Postbus 299, 2200 AG Noordwijk (Netherlands); Zinnecker, Hans [Deutsches SOFIA Institut, Universitaet Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany); Townsley, Leisa; Broos, Patrick [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park PA 16802 (United States)

2011-05-01

89

GIRMOS: an infrared multi-object spectrograph for Gemini  

NASA Astrophysics Data System (ADS)

Gemini have funded a design study to investigate the technologies needed in a versatile multi-object spectrograph for IR astronomy. We report on our investigations into wide- field spectroscopy using multiple integral-field units (MIFUs) to match particular areas of interest to the available detector(s). Such technologies enable integral field spectroscopy of several targets over a much wider field than can be covered with a single IFU. A brief overview of the scientific rationale for a multipel0IFU capability matched to multi-conjugate adaptive optics, and with its wider uncorrected field, on Gemini is given. A proposed method of deploying MIFUs is then described along with the optical consequences of the method.

Wright, Gillian S.; Sharples, Ray M.; Hastings, Peter R.; Wells, Martyn; Atad-Ettedgui, Eli; Allington-Smith, Jeremy R.; Robertson, David J.; Content, Robert; Parry, Ian R.

2000-08-01

90

A quantum-efficient systematics-free photon-counting optical imaging system for long baseline interferometric imaging of faint deep space objects  

Microsoft Academic Search

A four state Proxitronic image intensifier with system digital video readout was developed for use as a high detective quantum efficiency photon counting imaging detector optimized for long baseline speckle interferometric imaging of deep space objects. Accurate noise bias calibration requires low geometric distortion image intensifiers as well as linear video readout to yield a stable, calibratable photon point spread

E. Keith Hege

1990-01-01

91

Faint Dwarfs in Nearby Groups  

NASA Astrophysics Data System (ADS)

The number and distribution of dwarf satellite galaxies remain a critical test of cold dark matter-dominated structure formation on small scales. Until recently, observational information about galaxy formation on these scales has been limited mainly to the Local Group. We have searched for faint analogues of Local Group dwarfs around nearby bright galaxies, using a spatial clustering analysis of the photometric catalog of the Sloan Digital Sky Survey (SDSS) Data Release 8. Several other recent searches of SDSS have detected clustered satellite populations down to ?mr ? (m r, sat - m r, main) ~ 6-8, using photometric redshifts to reduce background contamination. SDSS photometric redshifts are relatively imprecise, however, for faint and nearby galaxies. Instead, we use angular size to select potential nearby dwarfs and consider only the nearest isolated bright galaxies as primaries. As a result, we are able to detect an excess clustering signal from companions down to ?mr = 12, 4 mag fainter than most recent studies. We detect an overdensity of objects at separations <400 kpc, corresponding to about 4.6 ± 0.5 satellites per central galaxy, consistent with the satellite abundance expected from the Local Group, given our selection function. Although the sample of satellites detected is incomplete by construction, since it excludes the least and most compact dwarfs, this detection provides a lower bound on the average satellite luminosity function, down to luminosities corresponding to the faintest "classical" dwarfs of the Local Group.

Speller, Ryan; Taylor, James E.

2014-06-01

92

Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy  

NASA Technical Reports Server (NTRS)

A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straight-forwardly be quantitatively integrated over the angular aperture without considering non-uniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

Pepper, Stephen V.

1995-01-01

93

A substation infrared temperature monitoring and warning system with object separation and image registration  

NASA Astrophysics Data System (ADS)

To find the defects of the apparatus in a substation in the early stage, an infrared temperature monitoring and warning system is established. This system can monitor the electrical equipment automatically the movement condition. The systemic circulation gathers the transformer substation electrical equipment the infrared imagery, the extraction goal equipment temperature information, and with the history database creation connection, the synthesis distinguishes the equipment failure information. In view of image gathering when because the mechanical drive creates the deviation, proposed one kind of object-oriented division and the image matching adjustment algorithm, first carries on the object division and the configuration definition to the image, then uses based on the phase correlation carries on the matching with the Harris vertex match image matching method to the deviation image. In this paper, a infrared remote-viewing image registration based on phase correlation and feature points matching is presented. Several experiments illustrate that this method has a good performance of reliability and accuracy.

Lin, Lihua; Wu, Dongmei; Liu, Jian; Zhang, Xinghua

2010-08-01

94

Far infrared spectroscopy of FU Ori objects. ISO-LWS observations  

Microsoft Academic Search

We present the results of the first spectrophotometric observations of a sample of FU Ori objects obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The [OI] (63 mu m) and the [CII] (158 mu m) lines are commonly observed in all spectra (both ON and OFF source). The observational novelty is the presence in

D. Lorenzetti; T. Giannini; B. Nisini; M. Benedettini; M. Creech-Eakman; G. A. Blake; E. F. van Dishoeck; M. Cohen; R. Liseau; S. Molinari; S. Pezzuto; P. Saraceno; H. A. Smith; L. Spinoglio; G. J. White

2000-01-01

95

Short Time Scale Variability of the BL Lac Object OJ 287 in the Near-Infrared.  

National Technical Information Service (NTIS)

The results of a near infrared photometric monitoring of the BL Lacertae object OJ 287 are presented. The standard photometry of the J, H and K bands shows variability of maximum amplitude about 0.7 mag over the entire observing period of 23 months and ab...

D. Lorenzetti, E. Massaro, G. C. Perola, L. Spinoglio

1989-01-01

96

OBJECT X: THE BRIGHTEST MID-INFRARED POINT SOURCE IN M33  

SciTech Connect

We discuss the nature of the brightest mid-IR point source (which we dub Object X) in the nearby galaxy M33. Although multi-wavelength data on this object have existed in the literature for some time, it had not previously been recognized as the most luminous mid-IR object in M33 because it is entirely unremarkable in both optical and near-IR light. In the Local Group Galaxies Survey, Object X is a faint red source visible in VRI and H{alpha} but not U or B. It was easily seen at JHK{sub s} in the Two Micron All Sky Survey. It is the brightest point source in all four Spitzer IRAC bands and is also visible in the MIPS 24 {mu}m band. Its bolometric luminosity is {approx}5 x 10{sup 5} L{sub sun}. The source is optically variable on short timescales (tens of days) and is also slightly variable in the mid-IR, indicating that it is a star. Archival photographic plates (from 1949 and 1991) show no optical source, so the star has been obscured for at least half a century. Its properties are similar to those of the Galactic OH/IR star IRC+10420, which has a complex dusty circumstellar structure resulting from episodic low-velocity mass ejections. We propose that Object X is an M {approx}> 30 M{sub sun} evolved star obscured in its own dust ejected during episodic mass-loss events over at least {approx}half a century. It may emerge from its current ultra-short evolutionary phase as a hotter post-red-supergiant star analogous to M33 Var A. The existence and rarity of such objects can be an important probe of a very brief yet eventful stellar evolutionary phase.

Khan, Rubab; Stanek, K. Z.; Kochanek, C. S. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Bonanos, A. Z., E-mail: khan@astronomy.ohio-state.edu, E-mail: kstanek@astronomy.ohio-state.edu, E-mail: ckochanek@astronomy.ohio-state.edu, E-mail: bonanos@astro.noa.gr [Institute of Astronomy and Astrophysics, National Observatory of Athens, I. Metaxa and Vas. Pavlou St., P. Penteli, 15236 Athens (Greece)

2011-05-01

97

Detecting moving objects in airborne forward looking infra-red sequences  

Microsoft Academic Search

In this paper we propose a system that detects independently moving objects (IMOs) in forward looking infra-red (FLIR) image sequences taken from an airborne, moving platform. Ego-motion effects are removed through a robust multi-scale affine image registration process. Consequently, areas with residual motion indicate object activity. These areas are detected, refined and selected using a Bayes' classifier. The remaining regions

Alexander Strehl; J. K. Aggarwal

1999-01-01

98

Characterization of High Proper Motion Objects from the Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

We present an analysis of high proper motion objects that we have found in a recent study and in this work with multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE). Using photometry and proper motions from the Two Micron All-Sky Survey and WISE, we have identified the members of this sample that are likely to be late-type, nearby, or metal-poor. We have performed optical and near-infrared spectroscopy on 41 objects, from which we measure spectral types that range from M4-T2.5. This sample includes 11 blue L dwarfs and 5 subdwarfs; the latter were also classified as such in the recent study by Kirkpatrick and coworkers. Based on their spectral types and photometry, several of our spectroscopic targets may have distances of <20 pc with the closest at ~12 pc. The tangential velocities implied by the spectrophotometric distances and proper motions indicate that four of the five subdwarfs are probably members of the Galactic halo while several other objects, including the early-T dwarf WISE J210529.08-623558.7, may belong to the thick disk. Based on data from the Wide-field Infrared Survey Explorer, the Two Micron All-Sky Survey, the NASA Infrared Telescope Facility, Gemini Observatory, the SOAR Telescope, and the Magellan Telescopes.

Luhman, K. L.; Sheppard, Scott S.

2014-06-01

99

A novel infrared object detection method based on the generalized cumulative sum in IRST system  

NASA Astrophysics Data System (ADS)

Aiming at the infrared object detection applications, a novel generalized cumulative sum processing is presented. Since in a typical IRST application system, object appearing and vanishing can be regarded as the change-point detection problem in Statistics. One of the effective solutions is the generalized cumulative sum processing (GCUSUM). Analyses are focused on the detection threshold value selection of GCUSUM algorithm and relations among the threshold value and false alarm rate, detection probability and signal-noise rate. The further researches extend a uniform band IRST system into the multiple band IRST system and improve the realization of GCUSUM algorithm. Results of theoretical analysis and simulation show that our modified algorithm has excellent object detection performance in an infrared image sequences from a real IRST system.

Tian, Yuexin; Gao, Kun; Liu, Ying; Bin, Qi; Xu, Zhigao

2013-12-01

100

Circumstellar Environments of Luminous Infrared Stellar Objects in the Magellanic Clouds  

NASA Technical Reports Server (NTRS)

Young stars are formed out of the interstellar medium (ISM) which is replenished by mass loss rates from evolved stars. Circumstellar matter around young and evolved stellar objects usually emits energy in the infrared (IR) wavelength range as the matter is heated by the central star. Surveys of the Magellanic Clouds with the Spitzer Space Telescope in the 3.6-160 micron range have previously been completed. These surveys have led to catalogs of infrared sources: which include HII regions, young stars, super giants, asymptotic giant branch (AGB) stars, post-asymptotic giant branch (post-AGB) stars, and planetary nebulae. The utility of such surveys can be improved upon by using Hubble Space Telescope (HST) data. HST provides higher angular resolution than Spitzer and has allowed for more detailed investigation of these luminous IR objects. This project used previously obtained HST archival data to examine luminous IR objects at optical wavelengths. This allows for the reclassification of stellar objects previously thought as one type of object or in a particular stage of their stellar evolution. An overall objective of this project included looking for extended nebulosity around evolved stars to better understand the life cycle of such objects and classify these nebulae by shape.

Azari, Abigail; Sahai, Raghvendra

2011-01-01

101

New method for unsupervised segmentation of moving objects in infrared videos  

NASA Astrophysics Data System (ADS)

A new method for unsupervised segmentation of moving objects in infrared videos is presented. This method consists of two steps: difference image quantization and spatial segmentation. In the first step, the changed pixels in the difference image are quantized to several classes by using Bayes decision. It can be used to cluster the changed pixels belonging to the same moving object together. The pixels of the difference image are replaced by their corresponding class labels, thus forming a class-map of the difference image. In the second step, each class in the class-map is considered as a subset of the possible seeds of moving objects. A self-adaptive region growing method is then used to image segmentation on the basis of these different subsets. One of the focuses of this work is on spatial segmentation, where a criterion is proposed for evaluation of moving object segmentation without ground truth in infrared videos. This criterion is used to evaluate the performance of the segmentation masks grown from different subsets of the possible seeds. The best segmented image is determined to be the final segmentation result. Experiments show the advantage and robustness of the proposed algorithm on real infrared videos.

Min, Chaobo; Zhang, Junju; Chang, Benkang; Zhang, Baohui; Li, Yingjie

2013-10-01

102

A multifrequency radio continuum and IRAS faint source survey of markarian galaxies  

NASA Technical Reports Server (NTRS)

Results are presented from a multifrequency radio continumm survey of Markarian galaxies (MRKs) and are supplemented by IRAS infrared data from the Faint Source Survey. Radio data are presented for 899 MRKs observed at nu = 4.755 GHz with the National Radio Astronomy Observatory (NRAO)-Green Bank 300 foot (91 m) telescope, including nearly 88% of those objects in Markarian lists VI-XIV. In addition, 1.415 GHz measurements of 258 MRKs, over 30% of the MRKs accessible from the National Aeronomy and Ionosphere Center (NAIC)-Arecibo, are reported. Radio continuum observations of smaller numbers of MRKs were made at 10.63 GHz and at 23.1 GHz and are also presented. Infrared data from the IRAS Faint Source Survey (Ver. 2) are presented for 944 MRKs, with reasonably secure identifications extracted from the NASA/IPAC Extragalactic Database. MRKs exhibit the same canonical infrared characteristics as those reported for various other galaxy samples, that is well-known enhancement of the 25 micrometer/60 micrometer color ratio among Seyfert MRKs, and a clear tendency for MRKs with warmer 60 micrometer/100 micrometer colors to also possess cooler 12 micrometer/25 micrometer colors. In addition, non-Seyfert are found to obey the well-documented infrared/radio luminosity correlation, with the tightest correlation seen for starburst MRKs.

Bicay, M. D.; Kojoian, G.; Seal, J.; Dickinson, D. F.; Malkan, M. A.

1995-01-01

103

Near-infrared (JHK) Spectroscopy of Young Stellar and Substellar Objects in Orion  

NASA Astrophysics Data System (ADS)

We performed low-resolution (R ~ 40) near-infrared (0.9-2.4 ?m) multi-object spectroscopy of 240 isolated point sources having apparent H-band magnitudes between 9 and 18 in the central 5' × 6' of the Orion Trapezium cluster. The observations were performed over four nights at the Canada-France-Hawaii Telescope using the visiting instrument SIMON, an infrared imager and multi-object spectrograph. We present the spectra of 104 objects with accurately derived spectral types including 7 new objects having masses below the hydrogen-burning limit, and 6 objects with masses below the deuterium-burning limit. The spectral classification is performed by fitting previously classified spectral templates of dwarf stars (K4-M3) and optically classified young stellar and substellar objects (M4-L0), to the entire 0.9-2.4 ?m spectral energy distribution in order to assign a spectral type and visual extinction for each object. Of the 104 objects studied, 44 have been previously classified spectroscopically using various techniques. We perform a rigorous comparison between the previous classifications and our own and find them to be in good agreement. Using the dereddened H-band magnitudes, the classified objects are used to create an Hertzsprung-Russell diagram for the cluster. We find that the previous age estimates of ~1 Myr to be consistent with our results. Consistent with previous studies, numerous objects are observed to have luminosities several magnitudes above the 1 Myr isochrone. Numerous objects exhibiting emission features in the J band are also reported.

Ingraham, P.; Albert, L.; Doyon, R.; Artigau, E.

2014-02-01

104

Near-infrared observations of young stellar objects in the Rho Ophiuchi dark cloud  

NASA Technical Reports Server (NTRS)

We have conducted an imaging survey of 1.4 sq pc of the Rho Ophiuchi dark cloud in the J, H, and K near-infrared photometric bands. Approximately 337 of our 481 detected sources are associated with the cloud, and we estimate that 48 percent of these have near-infrared excesses, indicative of disks or circumstellar material surrounding these young stellar objects (YSOs). The K-band luminosity function is significantly different in different regions of our survey area, suggesting that YSOs in these regions have different ages or mass functions. We estimate that the entire survey area has a high star-formation efficiency, at roughly 23 percent. Finally, our many newly detected sources provide a relatively large, uniformly sensitive sample of objects for study at longer wavelengths to better determine true source luminosities and evolutionary lifetimes.

Greene, Thomas P.; Young, Erick T.

1992-01-01

105

The Unusual Infrared Object HDF-N J123656.3+621322  

Microsoft Academic Search

We describe an object in the Hubble Deep Field North with very unusual near-infrared properties. It is readily visible in Hubble Space Telescope NICMOS images at 1.6 mum and from the ground at 2.2 mum, but it is undetected (with S\\/N<~2) in very deep WFPC2 and NICMOS data from 0.3 to 1.1 mum. The fnu flux density drops by a

Mark Dickinson; Christopher Hanley; Richard Elston; Peter R. Eisenhardt; S. A. Stanford; Kurt L. Adelberger; Alice Shapley; Charles C. Steidel; Casey Papovich; Alexander S. Szalay; Matthew A. Bershady; Christopher J. Conselice; Henry C. Ferguson; Andrew S. Fruchter

2000-01-01

106

Does faint galaxy clustering contradict gravitational instability?  

NASA Technical Reports Server (NTRS)

It has been argued, based on the weakness of clustering of faint galaxies, that these objects cannot be the precursors of present galaxies in a simple Einstein-de Sitter model universe with clustering driven by gravitational instability. It is shown that the assumptions made about the growth of clustering were too restrictive. In such a universe, the growth of clustering can easily be fast enough to match the data.

Melott, Adrian L.

1992-01-01

107

Observations of faint eclipsing cataclysmic variables  

Microsoft Academic Search

We present time-resolved photometry of six faint (V>17mag) cataclysmic variables (CVs); one of them is V849 Oph and the others are identified from the Sloan Digital Sky Survey (SDSS J0920+0042, SDSS J1327+6528, SDSS J1227+5139, SDSS J1607.02+3623, SDSS J1457+5148). The optical CCD photometric observations of these objects were performed at the TÜB?TAK National Observatory (Turkey) between February 2006 and March 2009.

Dicle Zengin Çamurdan; C. Muzaffer Çamurdan

2010-01-01

108

Optically faint X-ray sources in the Chandra deep field North: Spitzer constraints  

NASA Astrophysics Data System (ADS)

We investigate the properties of the most optically faint sources in the GOODS-N area (RAB > 26.5). These extremely optically faint populations present an uncharted territory although they represent an appreciable fraction of the X-ray sources in the GOODS-N field. The optically faint sources are believed to contain either red active galactic nuclei (AGN) at moderate redshifts or possibly quasi stellar objects (QSOs) at very high redshift. We compile our sample by first finding the 3.6 ?m IRAC counterparts of the X-ray sources and in turn by searching for the optical counterparts of the IRAC sources. No counterparts were found for 35 objects in the R-band Subaru optical images. Of these, 18 have HST ACS counterparts, while the remaining have no optical counterparts. The vast majority of our 35 sources are classified as extremely red objects (EROs) on the basis of their V606-KS lower limits. Their derived photometric redshifts show that these populate moderate redshifts (median z ~ 2.8), being at markedly different redshifts from the already spectroscopically identified population which peaks at z ~ 0.7. The Spitzer IRAC mid-IR colours of the sources without HST counterparts tend to lie within the mid-IR colour diagram AGN “wedge”, suggesting either QSO, ultra luminous infrared galaxy (ULIRG; Mrk231) templates or early-type galaxy templates at z > 3. A large fraction of our sources (17/35), regardless of whether they have HST counterparts, can be classified as mid-IR bright/optically faint sources (dust obscured galaxies) a class of sources which is believed to include many heavily absorbed AGN. The co-added X-ray spectrum of the optically faint sources is very flat, with a spectral index of ? ? 0.87, significantly flatter than the spectrum of the X-ray background. The optically faint (R > 26.5) X-ray sources constitute more than 50 per cent of the total X-ray population at redshifts z > 2, bearing important implications for the luminosity function and its evolution. Considering X-ray sources with 2 < z < 4 we find good agreement with a modified pure luminosity evolution (PLE) model.

Rovilos, E.; Georgantopoulos, I.; Akylas, A.; Fotopoulou, S.

2010-11-01

109

Near-Infrared Spectroscopy of Warm Spitzer-observed Near-Earth Objects  

NASA Astrophysics Data System (ADS)

We have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program. ExploreNEOs or “The Warm Spitzer NEO Survey: Exploring the history of the inner Solar System and near-Earth space” was allocated 500 hours over two years (2009-2011) to determine diameters and albedos for approximately 600 near-Earth objects using the 3.6 and 4.5 micron IRAC bands. We present the results of the SpeX component of our campaign. In order to increase our sample size we also include all near-infrared observations of ExploreNEOs targets in the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our complete dataset includes 125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey. The combination of the two surveys includes near-infrared spectroscopy of 187 ExploreNEOs targets. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We identified all potential ordinary chondrites within our sample and determined likely ordinary chondrite types using the equations derived by Dunn et al. 2010. Our resulting proportions of H, L, and LL ordinary chondrites are different than those previously calculated for ordinary chondrite-like near-Earth objects and meteorite falls.

Thomas, Cristina A.; Emery, J. P.; Trilling, D. E.; Delbo, M.; Hora, J. L.; Mueller, M.

2013-10-01

110

CENTAURS AND SCATTERED DISK OBJECTS IN THE THERMAL INFRARED: ANALYSIS OF WISE/NEOWISE OBSERVATIONS  

SciTech Connect

The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and scattered disk objects (SDOs) in the thermal infrared, including 15 new discoveries. We present analyses of these observations to estimate sizes and mean optical albedos. We find mean albedos of 0.08 {+-} 0.04 for the entire data set. Thermal fits yield average beaming parameters of 0.9 {+-} 0.2 that are similar for both SDO and Centaur sub-classes. Biased cumulative size distributions yield size-frequency distribution power law indices of {approx}-1.7 {+-} 0.3. The data also reveal a relation between albedo and color at the 3{sigma} level. No significant relation between diameter and albedos is found.

Bauer, James M. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 183-401, Pasadena, CA 91109 (United States); Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Grav, Tommy [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395 (United States); Blauvelt, Erin [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 183-401, Pasadena, CA 91109 (United States); Collaboration: WISE Team; PTF Team; and others

2013-08-10

111

Far-infrared photometry of compact extragalactic objects - Detection of 3C 345  

NASA Technical Reports Server (NTRS)

The first detection of a quasar between 10 and 1000 microns is reported. The observation permits (1) the determination of the intersection of the optical/infrared and millimeter continua; (2) more precise determination of the total luminosity; (3) the placing of limits on the contribution of any thermal dust emission to the total luminosity. The quasar is the first object ever to have been observed whose energy distribution peaks at wavelength of about 100 microns without a large contribution to the total luminosity from thermal dust emission. The observed flux density of 2.2 + or - 0.5 Jy at 100 microns and an upper limit of 0.5 + or - 0.6 Jy at 50 microns clearly define the overall energy distribution and show the quasar to be a powerful far-infrared source.

Harvey, P. M.; Wilking, B. A.; Joy, M.

1982-01-01

112

The effect of infrared and visible image fusion on object tracking using correlation matching  

NASA Astrophysics Data System (ADS)

This paper studies on how the performance of object tracking using correlation matching can be affected by the pixel-level infrared and visible image fusion approaches, as compared to tracking using single modality source images. Several classic grayscale and color image fusion approaches have been investigated, with the former including traditional DWT method and our proposed adaptive weighted average method based on fuzzy logic and the latter including both linear and nonlinear color transfer methods. Object tracking in various conditions has been tested on a representative set of both simulated and real captured image sequences. Experimental results suggest that the location precision and robustness of object tracking can be improved effectively using fused images. Among the various tested fusion approaches, the techniques of fuzzy logic based grayscale image fusion and nonlinear color transfer consistently offer the best tracking performance.

Yin, Songfeng; Cao, Liangcai; Jin, Guofan

2011-06-01

113

Infrared cloaking of arbitrary objects for surface waves by scattering cancelation method using graphene  

NASA Astrophysics Data System (ADS)

In this paper, a new method for realizing two dimensional cloaking based on scattering cancelation for surface waves is presented. A graphene sheet is considered as a negative permittivity material shell to create cloaking cover for a dielectric object. Appropriate electromagnetic characteristics of graphene in the cloaking shell can be achieved by variation of physical parameters, such as substrate thickness and gate voltage. In this study, by using these physical parameters, a simple cloaking structure for a dielectric cylinder versus surface plasmon polariton waves is introduced in the infrared regime. Reduction of radar cross section is attained as a criterion of cloaking.

Danaeifar, M.; Granpayeh, N.; Mohammadi, A.; Setayesh, A.

2014-06-01

114

Infrared Spectroscopy and Young Stellar Objects: Characterizing the Dust and Gas in Circumstellar Disks  

NASA Astrophysics Data System (ADS)

In this dissertation, I describe my work in infrared spectroscopy and in studying the circumstellar disks around young stellar objects. In the first part, I detail an electronic component I designed for the Texas Echelon Cross Echelle Spectrograph (TEXES), which has acted as a visiting instrument on Gemini North and the NASA Infrared Telescope Facility. In order to detect the incoming infrared flux, a bias voltage is applied across the detector to sweep out the photo-excited electrons. If the bias voltage is too weak, the electrons can recombine before being swept out, while a strong bias can create unstable photoconductive gain. The initial design of TEXES required the operator to open the electronics and change the bias voltage by hand. However, the optimal bias is not the same for different instrument modes, which wasted substantial observing time when changing instrument modes. In order to save future observing time, and to fulfill a precondition set by Gemini North for TEXES to act as a visiting instrument, I created an electronic component to change the detector bias from the computer control room. I investigate and characterize the optimal voltages for the Raytheon 2562 SiAs IBC "SIRTF" array for the different instrument modes used by TEXES. In the following sections, I describe our observing campaign using the Spitzer IRS module and three ground-based telescopes to investigate edge-on circumstellar disks and classical infrared companions. Observations of the terrestrial planet forming regions of circumstellar disks are difficult to obtain, but recent detections of molecular absorption originating from these regions have proven valuable for disk models. We were granted time with the Spitzer Space Telescope to observe seven targets classified as young stellar objects, likely with their disks seen edge-on, to search for molecular absorption features. We used ground-based telescopes, including Gemini South, W. M. Keck Observatory, and the European Southern Observatory's Very Large Telescope, to further investigate and characterize our targets. I begin with a comparison of the disks around DG Tau B and VV CrA, showing evidence for extensive grain growth and settling in DG Tau B and characterizing the disk geometry of VV CrA. I discuss findings of Glass I, which proves to be extremely variable and shows high ionization ratios of fine structure emission not previously seen in young stars. Finally, I discuss the disk geometry of DoAr 24E and investigate the source of high extinction toward the infrared companion of this binary system.

Kruger, Andrew James

115

THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. III. ANALYSIS OF 3CRR OBJECTS  

SciTech Connect

We present Spitzer photometric data for a complete sample of 19 low-redshift (z< 0.1) 3CRR radio galaxies as part of our efforts to understand the origin of the prodigious mid- to far-infrared (MFIR) emission from radio-loud active galactic nuclei (AGNs). Our results show a correlation between AGN power (indicated by [O III]{lambda}5007 emission line luminosity) and 24 {mu}m luminosity. This result is consistent with the 24 {mu}m thermal emission originating from warm dust heated directly by AGN illumination. Applying the same correlation test for 70 {mu}m luminosity against [O III] luminosity we find this relation to suffer from increased scatter compared to that of 24 {mu}m. In line with our results for the higher-radio-frequency-selected 2 Jy sample, we are able to show that much of this increased scatter is due to heating by starbursts that boost the far-infrared emission at 70 {mu}m in a minority of objects (17%-35%). Overall this study supports previous work indicating AGN illumination as the dominant heating mechanism for MFIR emitting dust in the majority of low-to-intermediate redshift radio galaxies (0.03 < z < 0.7), with the advantage of strong statistical evidence. However, we find evidence that the low-redshift broad-line objects (z < 0.1) are distinct in terms of their positions on the MFIR versus [O III] correlations.

Dicken, D.; Axon, D.; Robinson, A.; Kharb, P. [Department of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Tadhunter, C. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH (United Kingdom); Morganti, R., E-mail: dxdsps@rit.ed, E-mail: djasps@rit.ed, E-mail: axrsps@rit.ed, E-mail: c.tadhunter@sheffield.ac.u, E-mail: morganti@astron.n [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands)

2010-10-20

116

[Objective assessment of facial paralysis using local binary pattern in infrared thermography].  

PubMed

Facial paralysis is a frequently-occurring disease, which causes the loss of the voluntary muscles on one side of the face due to the damages the facial nerve and results in an inability to close the eye and leads to dropping of the angle of the mouth. There have been few objective methods to quantitatively diagnose it and assess this disease for clinically treating the patients so far. The skin temperature distribution of a healthy human body exhibits a contralateral symmetry. Facial paralysis usually causes an alteration of the temperature distribution of body with the disease. This paper presents the use of the histogram distance of bilateral local binary pattern (LBP) in the facial infrared thermography to measure the asymmetry degree of facial temperature distribution for objective assessing the severity of facial paralysis. Using this new method, we performed a controlled trial to assess the facial nerve function of the healthy subjects and the patients with Bell's palsy respectively. The results showed that the mean sensitivity and specificity of this method are 0.86 and 0.89 respectively. The correlation coefficient between the asymmetry degree of facial temperature distribution and the severity of facial paralysis is an average of 0.657. Therefore, the histogram distance of local binary pattern in the facial infrared thermography is an efficient clinical indicator with respect to the diagnosis and assessment of facial paralysis. PMID:23488134

Liu, Xulong; Hong, Wenxue; Zhang, Tao; Wu, Zhenying

2013-02-01

117

NEAR-INFRARED H{sub 2} AND CONTINUUM SURVEY OF EXTENDED GREEN OBJECTS  

SciTech Connect

The Spitzer GLIMPSE survey has revealed a number of 'Extended Green Objects' (EGOs) that display extended emission at 4.5 {mu}m. These EGOs are potential candidates for high-mass protostellar outflows. We used high-resolution (<1'') H{sub 2} 1-0 S(1) line, K-, and H-band images from the United Kingdom Infrared Telescope to study 34 EGOs to investigate their nature. We found that 12 EGOs exhibit H{sub 2} outflows (two with chains of H{sub 2} knotty structures, five with extended H{sub 2} bipolar structures, three with extended H{sub 2} lobes, and two with pairs of H{sub 2} knots). Of the 12 EGOs with H{sub 2} outflows, three exhibit similar morphologies between the 4.5 {mu}m and H{sub 2} emission. However, the remaining nine EGOs show that the H{sub 2} features are more extended than the continuum features, and the H{sub 2} emission is seldom associated with continuum emission. Furthermore, the morphologies of the near-infrared continuum and 4.5 {mu}m emission are similar to each other for those EGOs with K-band emission, implying that at least part of the IRAC-band continuum emission of EGOs comes from scattered light from the embedded young stellar objects.

Lee, Hsu-Tai; Takami, Michihiro; Duan, Hao-Yuan; Karr, Jennifer; Su, Yu-Nung; Liu, Sheng-Yuan; Yeh, Cosmos C. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Froebrich, Dirk, E-mail: htlee@asiaa.sinica.edu.tw [Centre for Astrophysics and Planetary Science, University of Kent, Canterbury CT2 7NH (United Kingdom)

2012-05-01

118

X-RAY AND INFRARED EMISSION FROM YOUNG STELLAR OBJECTS NEAR LkH{alpha} 101  

SciTech Connect

We report on a multiwavelength study of a partially embedded region of star formation centered on the Herbig Be star LkH{alpha} 101. Using two 40 ks Chandra observations, we detect 213 X-ray sources in the {approx}17' x 17' ACIS-I field. We combine the X-ray data with Two Micron All Sky Survey near-IR observations and Spitzer IRAC and MIPS 24 {mu}m observations to obtain a complete picture of the cluster. A total of 158 of the X-ray sources have infrared counterparts. Of these, we find nine protostars, 48 Class II objects, five transition objects, and 72 Class III objects. From the Spitzer data we identify an additional 10 protostars, 53 Class II objects, and four transition disk candidates which are not detected by Chandra. We obtained optical spectra of a sample of both X-ray-detected and non-X-ray-detected objects. Combining the X-ray, Spitzer, and spectral data, we obtain independent estimates of cluster distance and the total cluster size-excluding protostars. We obtain consistent distance estimates of 510{sup +100}{sub -40} pc and a total cluster size of 255{sup +50}{sub -25} stars. We find the Class II:III ratio is about 5:7 with some evidence that the Class III sources are spatially more dispersed. The cluster appears very young with three sites of active star formation and a median age of about 1 Myr.

Wolk, Scott J.; Bourke, Tyler L.; Spitzbart, Bradley D. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Winston, Elaine [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Gutermuth, Robert [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Megeath, S. Thomas [Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Osten, Rachel [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

2010-05-20

119

The faint galaxy contribution to the diffuse extragalactic background light  

NASA Technical Reports Server (NTRS)

Models of the faint galaxy contribution to the diffuse extragalactic background light are presented, which are consistent with current data on faint galaxy number counts and redshifts. The autocorrelation function of surface brightness fluctuations in the extragalactic diffuse light is predicted, and the way in which these predictions depend on the cosmological model and assumptions of biasing is determined. It is confirmed that the recent deep infrared number counts are most compatible with a high density universe (Omega-0 is approximately equal to 1) and that the steep blue counts then require an extra population of rapidly evolving blue galaxies. The faintest presently detectable galaxies produce an interesting contribution to the extragalactic diffuse light, and still fainter galaxies may also produce a significant contribution. These faint galaxies still only produce a small fraction of the total optical diffuse background light, but on scales of a few arcminutes to a few degrees, they produce a substantial fraction of the fluctuations in the diffuse light.

Cole, Shaun; Treyer, Marie-Agnes; Silk, Joseph

1992-01-01

120

Infrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula cluster  

NASA Astrophysics Data System (ADS)

We present near-infrared long-slit and multislit spectra of low-mass brown dwarf candidates in the Orion nebula cluster. The long-slit data were observed in the H and K bands using NIRI on the Gemini-North Telescope. The multi-object spectroscopic observations were made using IRIS2 on the Anglo-Australian Telescope at H band. We develop a spectral typing scheme based on optically calibrated, near-infrared spectra of young sources in the Taurus and IC 348 star-forming regions with spectral types M3.0 to M9.5. We apply our spectral typing scheme to 52 sources, including previously published UKIRT and GNIRS spectra. 40 objects show strong water absorption with spectral types of M3 to >M9.5. The latest type objects are provisionally classified as early L types. We plot our sources on Hertzsprung-Russell diagrams overlaid with theoretical pre-main-sequence isochrones. The majority of our objects lie close to or above the 1-Myr isochrone, leading to an average cluster age that is <1 Myr. We find 38 sources lie at or below the hydrogen-burning limit (0.075Msolar). 10 sources potentially have masses below the deuterium-burning limit (0.012Msolar). We use a Monte Carlo approach to model the observed luminosity function with a variety of cluster age and mass distributions. The lowest ?2 values are produced by an age distribution centred at 1 Myr, with a mass function that declines at substellar masses according to an M? power law in the range ? = 0.3-0.6. We find that truncating the mass function at 0.012Msolar produces luminosity functions that are starved of the faintest magnitudes, even when using bimodal age populations that contain 10-Myr-old sources. The results of these Monte Carlo simulations therefore support the existence of a planetary mass population in the ONC.

Weights, D. J.; Lucas, P. W.; Roche, P. F.; Pinfield, D. J.; Riddick, F.

2009-01-01

121

a Faint and Lonely Brown Dwarf in the Solar Vicinity  

NASA Astrophysics Data System (ADS)

Discovery of KELU-1 Promises New Insights into Strange Objects Brown Dwarfs are star-like objects which are too small to become real stars, yet too large to be real planets. Their mass is too small to ignite those nuclear processes which are responsible for the large energies and high temperatures of stars, but it is much larger than that of the planets we know in our solar system. Until now, very few Brown Dwarfs have been securely identified as such. Two are members of double-star systems, and a few more are located deep within the Pleiades star cluster. Now, however, Maria Teresa Ruiz of the Astronomy Department at Universidad de Chile (Santiago de Chile), using telescopes at the ESO La Silla observatory, has just discovered one that is all alone and apparently quite near to us. Contrary to the others which are influenced by other objects in their immediate surroundings, this new Brown Dwarf is unaffected and will thus be a perfect object for further investigations that may finally allow us to better understand these very interesting celestial bodies. It has been suggested that Brown Dwarfs may constitute a substantial part of the unseen dark matter in our Galaxy. This discovery may therefore also have important implications for this highly relevant research area. Searching for nearby faint stars The story of this discovery goes back to 1987 when Maria Teresa Ruiz decided to embark upon a long-term search (known as the Calan-ESO proper-motion survey ) for another type of unusual object, the so-called White Dwarfs , i.e. highly evolved, small and rather faint stars. Although they have masses similar to that of the Sun, such stars are no larger than the Earth and are therefore extremely compact. They are particularly interesting, because they most probably represent the future end point of evolution of our Sun, some billions of years from now. For this project, the Chilean astronomer obtained large-field photographic exposures with the 1-m ESO Schmidt telescope at La Silla, each covering a sky area of 5 o.5 x 5 o.5. When comparing plates of the same sky field obtained at time intervals of several years [1] , she was able to detect, among the hundreds of thousands of stellar images on the plates, a few faint ones whose positions had changed a little in the meantime. The search technique is based on the fact that such a shift is a good indicator of the object being relatively nearby. It must therefore also be intrinsically faint, i.e. a potential White Dwarf candidate. On every pair of plates, approximately twenty faint moving objects were detected with proper motions [2] of more than 0.25 arcsec per year. Indeed, follow-up spectroscopic observations showed that about 20 percent of these or about four per plate were White Dwarfs. Until now, a total of forty new White Dwarfs have been discovered during this very successful project, i.e. over ten times more than originally expected. And then - a Brown Dwarf! Caption to ESO PR Photo 11/97 [JPEG, 144k] ESO Press Photo 11/97 When checking two plates with a time inverval of 11 years, Maria Teresa Ruiz earlier this year discovered a very faint object in the southern constellation of Hydra (The Water-Snake), moving at 0.35 arcsec per year (cf. ESO Press Photo 11/97). In order to establish its true nature, she obtained its spectrum (in the visual to near-infrared region from wavelengths 450-1000 nm) on March 15 using the ESO 3.6-m telescope and the EFOSC1 spectrograph. Caption to ESO PR Photo 12/97 [GIF, 35k] ESO Press Photo 12/97 To her great surprise, the spectrum was of a type never seen before and certainly not that of a White Dwarf or any other easily identifiable type of star (cf. ESO Press Photo 12/97). In particular, there were no signs of spectral bands of titanium oxide (TiO) or vanadium oxide (VO) which are common in very cool stars, nor of the spectral lines seen in White Dwarfs. On the other hand, an absorption line of the short-lived element lithium was identified, as well as a hydrogen line in emission. However, when the colour of this mysterious object was measured

1997-04-01

122

Analysis of the DNA Fourier transform-infrared microspectroscopic signature using an all-reflecting objective.  

PubMed

The Fourier transform-infrared (FT-IR) signature of dry samples of DNA and DNA-polypeptide complexes, as studied by IR microspectroscopy using a diamond attenuated total reflection (ATR) objective, has revealed important discriminatory characteristics relative to the PO2(-) vibrational stretchings. However, DNA IR marks that provide information on the sample's richness in hydrogen bonds have not been resolved in the spectral profiles obtained with this objective. Here we investigated the performance of an "all reflecting objective" (ARO) for analysis of the FT-IR signal of hydrogen bonds in DNA samples differing in base richness types (salmon testis vs calf thymus). The results obtained using the ARO indicate prominent band peaks at the spectral region representative of the vibration of nitrogenous base hydrogen bonds and of NH and NH2 groups. The band areas at this spectral region differ in agreement with the DNA base richness type when using the ARO. A peak assigned to adenine was more evident in the AT-rich salmon DNA using either the ARO or the ATR objective. It is concluded that, for the discrimination of DNA IR hydrogen bond vibrations associated with varying base type proportions, the use of an ARO is recommended. PMID:24792446

Mello, Maria Luiza S; Vidal, Benedicto C

2014-06-01

123

[Objective assessment of facial paralysis using infrared thermography and formal concept analysis].  

PubMed

This paper presented a novel approach to objective assessment of facial nerve paralysis based on infrared thermography and formal concept analysis. Sixty five patients with facial nerve paralysis on one side were included in the study. The facial temperature distribution images of these 65 patients were captured by infrared thermography every five days during one-month period. First, the facial thermal images were pre-processed to identify six potential regions of bilateral symmetry by using image segmentation techniques. Then, the temperature differences on the left and right sides of the facial regions were extracted and analyzed. Finally, the authors explored the relationships between the statistical averages of those temperature differences and the House-Brackmann score for objective assessment degree of nerve damage in a facial nerve paralysis by using formal concept analysis. The results showed that the facial temperature distribution of patients with facial nerve paralysis exhibited a contralateral asymmetry, and the bilateral temperature differences of the facial regions were greater than 0.2 degrees C, whereas in normal healthy individuals these temperature differences were less than 0.2 degrees C. Spearman correlation coefficient between the bilateral temperature differences of the facial regions and the degree of facial nerve damage was an average of 0.508, which was statistically significant (p < 0.05). Furthermore, if one of the temperature differences of bilateral symmetry on facial regions was greater than 0.2 degrees C, and all were less than 0.5 degrees C, facial nerve paralysis could be determined as for the mild to moderate; if one of the temperature differences of bilateral symmetry was greater than 0.5 degrees C, facial nerve paralysis could be determined as for serious. In conclusion, this paper presents an automated technique for the computerized analysis of thermal images to objectively assess facial nerve related thermal dysfunction by using formal concept analysis theory, which may benefit the clinical diagnosis and treatment of facial nerve paralysis. PMID:25007603

Liu, Xu-Long; Hong, Wen-Xue; Liu, Jie-Min

2014-04-01

124

Near-infrared Variability among Young Stellar Objects in the Star Formation Region Cygnus OB7  

NASA Astrophysics Data System (ADS)

We present an analysis of near-infrared time-series photometry in J, H, and K bands for about 100 epochs of a 1° × 1° region of the Lynds 1003/1004 dark cloud in the Cygnus OB7 region. Augmented by data from the Wide-field Infrared Survey Explorer, we identify 96 candidate disk bearing young stellar objects (YSOs) in the region. Of these, 30 are clearly Class I or earlier. Using the Wide-Field Imaging Camera on the United Kingdom Infrared Telescope, we were able to obtain photometry over three observing seasons, with photometric uncertainty better than 0.05 mag down to J ? 17. We study detailed light curves and color trajectories of ~50 of the YSOs in the monitored field. We investigate the variability and periodicity of the YSOs and find the data are consistent with all YSOs being variable in these wavelengths on timescales of a few years. We divide the variability into four observational classes: (1) stars with periodic variability stable over long timescales, (2) variables which exhibit short-lived cyclic behavior, (3) long-duration variables, and (4) stochastic variables. Some YSO variability defies simple classification. We can explain much of the observed variability as being due to dynamic and rotational changes in the disk, including an asymmetric or changing blocking fraction, changes to the inner disk hole size, as well as changes to the accretion rate. Overall, we find that the Class I:Class II ratio of the cluster is consistent with an age of <1 Myr, with at least one individual, wildly varying source ~100, 000 yr old. We have also discovered a Class II eclipsing binary system with a period of 17.87 days.

Wolk, Scott J.; Rice, Thomas S.; Aspin, Colin

2013-08-01

125

NEAR-INFRARED VARIABILITY AMONG YOUNG STELLAR OBJECTS IN THE STAR FORMATION REGION CYGNUS OB7  

SciTech Connect

We present an analysis of near-infrared time-series photometry in J, H, and K bands for about 100 epochs of a 1 Degree-Sign Multiplication-Sign 1 Degree-Sign region of the Lynds 1003/1004 dark cloud in the Cygnus OB7 region. Augmented by data from the Wide-field Infrared Survey Explorer, we identify 96 candidate disk bearing young stellar objects (YSOs) in the region. Of these, 30 are clearly Class I or earlier. Using the Wide-Field Imaging Camera on the United Kingdom Infrared Telescope, we were able to obtain photometry over three observing seasons, with photometric uncertainty better than 0.05 mag down to J Almost-Equal-To 17. We study detailed light curves and color trajectories of {approx}50 of the YSOs in the monitored field. We investigate the variability and periodicity of the YSOs and find the data are consistent with all YSOs being variable in these wavelengths on timescales of a few years. We divide the variability into four observational classes: (1) stars with periodic variability stable over long timescales, (2) variables which exhibit short-lived cyclic behavior, (3) long-duration variables, and (4) stochastic variables. Some YSO variability defies simple classification. We can explain much of the observed variability as being due to dynamic and rotational changes in the disk, including an asymmetric or changing blocking fraction, changes to the inner disk hole size, as well as changes to the accretion rate. Overall, we find that the Class I:Class II ratio of the cluster is consistent with an age of <1 Myr, with at least one individual, wildly varying source {approx}100, 000 yr old. We have also discovered a Class II eclipsing binary system with a period of 17.87 days.

Wolk, Scott J.; Rice, Thomas S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Aspin, Colin [Institute for Astronomy, University of Hawaii at Manoa, 640 North Aohoku Place, Hilo, HI 96720 (United States)

2013-08-20

126

Object recognition in infrared image sequences using scale invariant feature transform  

NASA Astrophysics Data System (ADS)

In this paper, we propose an automated target recognition by using scale-invariant feature transform (SIFT) in PowerPC-based infrared (IR) imaging system. An IR image can be acquired more feature values at night than in the daytime, but visual image can be acquired more feature values in the daytime. IR-based object recognition puts application into digital surveillance system because it exist some more feature values at night than in the daytime. Feature of IR image in its system appears a little feature value in the daytime. It is not comprised within an effective feature values at a visual image from an IR of the daytime. Proposed method consists of two stages. First, we must localize the interest point in position and scale of moving objects. Second, we must build a description of the interest point and recognize moving objects. Proposed method uses SIFT for an effective feature extraction in PowerPC-based IR imaging system. Proposed SIFT method consists of scale space, extrema detection, orientation assignment, key point description, and feature matching. SIFT descriptor sets up extensive range about 1.5 times than visual image when feature value of SIFT in IR image is less than visual image. Because an object in IR image is analogized by field test that it exist more expanse form than visual image. Therefore, proposed SIFT descriptor is constituted at more expanse term for a precise matching of object. Based on experimental results, the proposed method is extracted object's feature values in PowerPC-based IR imaging system, and the result is presented by experiment.

Park, Changhan; Bae, Kyung-hoon; Jung, Jik-Han

2008-05-01

127

NESSI: an optimized Near-Infrared (NIR) Multi-Object Spectrograph (MOS) for exoplanet studies  

NASA Astrophysics Data System (ADS)

NESSI: the New Mexico Tech Extra(solar)planet Spectroscopic Survey Instrument is a ground-based multi-object spectrograph that operates in the near-infrared and is being deployed this fall at the Magdalena Ridge Observatory 2.4 m telescope. When completed later this year, it is expected to be used to characterize the atmospheres of transiting exoplanets with unprecedented ground-based accuracies down to about K = 9 magnitude. The superior capabilities of NEESI for this type of work lay, in part, in the design philosophy used for the instrument which is well-focused on the exoplanet case. We report here on this design philosophy, detail and status of the design and assembly, and preparation for first light in the fall of 2012.

Creech-Eakman, M. J.; Jurgenson, C. A.; Santoro, F. G.; Bloemhard, H.; Boston, P. J.; Deroo, P. D.; Hrynevych, M.; Jimenez, S. R.; Olivares, A. M.; Napolitano, M.; Salcido, C. D.; Schmidt, L. M.; Selina, R.; Swain, M. R.; Vasisht, G.

2012-09-01

128

Visible and infrared investigations of planet-crossing asteroids and outer solar system objects  

NASA Technical Reports Server (NTRS)

A major effort was directed toward 951 Gaspra in preparation for the Galileo encounter in October 1991. Most of the observational work involved photometry, for purposes of investigating the rotational state and phase function of the asteroid to help plan the encounter, and for purposes of navigating the spacecraft to the object. Work was also done with radiometric data obtained with the IRTF at NASA's request, for which simultaneous visible photometry was acquired with the University of Hawaii 2.24-m telescope. The results from the observations made during the 1990 opposition were published by Goldader et al. The main results reported include a rotational period of 7.04246 hours, an absolute visual magnitude of 11.8026, a slope parameter of 0.285, an early estimate of a high obliquity, an infrared spectrum indicating an olivine-rich composition, and 13 astrometric positions.

Tholen, David J.

1991-01-01

129

A Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the (rho) Ophiuchi Cloud Core  

NASA Technical Reports Server (NTRS)

Results of a comprehensive, new, ground-based mid-infrared imaging survey of the young stellar population of the (rho) Ophiuchi cloud are presented. Data were acquired at the Palomar 5m and at the Keck 10m telescopes with the MIRLIN and LWS instruments, at 0'.5 and 0'.25 resolutions, respectively. Of 172 survey objects, 85 were detected. Among the 22 multiple systems observed, 15 were resolved and their individual component fluxes determined. A plot of the frequency distribution of the detected objects with SED spectral slope shows that YSOs spend approx.4 x 10(exp 5) yr in the flat-spectrum phase, clearing out their remnant infall envelopes. Mid-infrared variability is found among a significant fraction of the surveyed objects and is found to occur for all SED classes with optically thick disks. Large-amplitude near-infrared variability, also found for all SED classes with optically thick disks, seems to occur with somewhat higher frequency at the earlier evolutionary stages. Although a general trend of mid-infrared excess and near-infrared veiling exists progressing through SED classes, with Class I objects generally exhibiting r(sub K) >= 1, flat-spectrum objects with r(sub K) >= 0.58, and Class III objects with r(sub K) =0, Class II objects exhibit the widest range of r(sub K) values, ranging from 0 <= r(sub K) <= 4.5. However, the highly variable value of veiling that a single source can exhibit in any of the SED classes in which active disk accretion can take place is striking and is direct observational evidence for highly time-variable accretion activity in disks. Finally, by comparing mid-infrared versus near-infrared excesses in a subsample with well-determined effective temperatures and extinction values, disk-clearing mechanisms are explored. The results are consistent with disk clearing proceeding from the inside out.

Barsony, Mary; Ressler, Michael E.; Marsh, Kenneth A.

2005-01-01

130

Integration, Testing and Performance of the Infrared Multi-Object Spectrometer  

NASA Technical Reports Server (NTRS)

The Infrared Multi-Object Spectrometer (IRMOS) is a principle investigator-class instrument for the Kitt Peak National Observatory 2.1 m and Mayall 3.8 m telescopes. IRMOS is a near-IR (0.8 - 2.5 micron) spectrometer with low-to mid-resolving power (R = lambda/delta lambda = 300 - 3000). On the 3.8 m telescope, IRMOS produces simultaneous spectra of approximately 100 objects in its approximately 3 x 2 arcmin field of view using a commercial micro electro-mechanical systems (MEMS) digital micro-mirror device (DMD) from Texas Instruments. The multi-mirror array DMD operates as a real-time programmable slit mask. The all-reflective optical design consists of two imaging subsystems. The focal reducer images the focal plane of the telescope onto the DMD field stop, and the spectrograph images the DMD onto a large-format detector. The instrument operates at approximately 80 K, cooled by a single electro-mechanical cryocooler. The bench and all components are made from aluminum 6061-T651. There are three cryogenic mechanisms. We describe laboratory integration and test of IRMOS before shipment to Kitt Peak. We give an overview of the optical alignment technique and integration of optical, mechanical, electrical and cryogenic subsystems. We compare optical test results to model predictions of point spread function size and morphology, contrast, and stray light. We discuss some lessons learned and conclude with a prediction for performance on the telescope.

Ohl, Raymond G.; Connelly, Joseph A.; Boyle, Robert F.; Derro, Rebecca J.; Greenhouse, Matthew A.; Madison, Timothy J.; Mentzell, J. Eric; Sparr, Leroy M.; Hylan, Jason E.; Ray, Knute

2003-01-01

131

INFRARED AND KINEMATIC PROPERTIES OF THE SUBSTELLAR OBJECT G 196-3 B  

SciTech Connect

We report unusual near- and mid-infrared photometric properties of G 196-3 B, the young substellar companion at 16'' from the active M2.5-type star G 196-3 A, using data taken with the IRAC and MIPS instruments onboard Spitzer. G 196-3 B shows markedly redder colors at all wavelengths from 1.6 up to 24 {mu}m than expected for its spectral type, which is determined at L3 from optical and near-infrared spectra. We discuss various physical scenarios to account for its reddish nature and conclude that a low-gravity atmosphere with enshrouded upper atmospheric layers and/or a warm dusty disk/envelope provides the most likely explanations, the two of them consistent with an age in the interval 20-300 Myr. We also present new and accurate separate proper motion measurements for G 196-3 A and B confirming that both objects are gravitationally linked and share the same motion within a few mas yr{sup -1}. After integration of the combined spectrophotometric spectral energy distributions, we obtain the result that the difference in the bolometric magnitudes of G 196-3 A and B is 6.15 {+-} 0.10 mag. Kinematic consideration of the Galactic space motions of the system for distances in the interval 15-30 pc suggests that the pair is a likely member of the Local Association and that it lies near the past positions of young star clusters like {alpha} Persei less than 85 Myr ago, where the binary might have originated. At these young ages, the mass of G 196-3 B would be in the range 12-25 M {sub Jup}, close to the frontier between planets and brown dwarfs.

Zapatero Osorio, M. R.; Caballero, J. A. [Centro de AstrobiologIa (CSIC-INTA), Crta. Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Rebolo, R.; Bihain, G.; Bejar, V. J. S.; Alvarez, C., E-mail: mosorio@cab.inta-csic.e, E-mail: rrl@iac.e, E-mail: gbihain@iac.e, E-mail: vbejar@iac.e [Instituto de Astrofisica de Canarias (IAC), C. VIa Lactea s/n, E-38205 La Laguna, Tenerife (Spain)

2010-06-01

132

Massive Young Stellar Objects in the Galactic Center. I. Spectroscopic Identification from Spitzer Infrared Spectrograph Observations  

NASA Astrophysics Data System (ADS)

We present results from our spectroscopic study, using the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope, designed to identify massive young stellar objects (YSOs) in the Galactic center (GC). Our sample of 107 YSO candidates was selected based on Infrared Array Camera (IRAC) colors from the high spatial resolution, high sensitivity Spitzer/IRAC images in the Central Molecular Zone, which spans the central ~300 pc region of the Milky Way. We obtained IRS spectra over 5-35 ?m using both high- and low-resolution IRS modules. We spectroscopically identify massive YSOs by the presence of a 15.4 ?m shoulder on the absorption profile of 15 ?m CO2 ice, suggestive of CO2 ice mixed with CH3OH ice on grains. This 15.4 ?m shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We show that nine massive YSOs also reveal molecular gas-phase absorption from CO2, C2H2, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC. We fit YSO models to the observed spectral energy distributions and find YSO masses of 8-23 M sun, which generally agree with the masses derived from observed radio continuum emission. We find that about 50% of photometrically identified YSOs are confirmed with our spectroscopic study. This implies a preliminary star formation rate of ~0.07 M sun yr-1 at the GC.

An, Deokkeun; Ramírez, Solange V.; Sellgren, Kris; Arendt, Richard G.; Adwin Boogert, A. C.; Robitaille, Thomas P.; Schultheis, Mathias; Cotera, Angela S.; Smith, Howard A.; Stolovy, Susan R.

2011-08-01

133

MASSIVE YOUNG STELLAR OBJECTS IN THE GALACTIC CENTER. I. SPECTROSCOPIC IDENTIFICATION FROM SPITZER INFRARED SPECTROGRAPH OBSERVATIONS  

SciTech Connect

We present results from our spectroscopic study, using the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope, designed to identify massive young stellar objects (YSOs) in the Galactic center (GC). Our sample of 107 YSO candidates was selected based on Infrared Array Camera (IRAC) colors from the high spatial resolution, high sensitivity Spitzer/IRAC images in the Central Molecular Zone, which spans the central {approx}300 pc region of the Milky Way. We obtained IRS spectra over 5-35 {mu}m using both high- and low-resolution IRS modules. We spectroscopically identify massive YSOs by the presence of a 15.4 {mu}m shoulder on the absorption profile of 15 {mu}m CO{sub 2} ice, suggestive of CO{sub 2} ice mixed with CH{sub 3}OH ice on grains. This 15.4 {mu}m shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We show that nine massive YSOs also reveal molecular gas-phase absorption from CO{sub 2}, C{sub 2}H{sub 2}, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC. We fit YSO models to the observed spectral energy distributions and find YSO masses of 8-23 M{sub sun}, which generally agree with the masses derived from observed radio continuum emission. We find that about 50% of photometrically identified YSOs are confirmed with our spectroscopic study. This implies a preliminary star formation rate of {approx}0.07 M{sub sun} yr{sup -1} at the GC.

An, Deokkeun [Department of Science Education, Ewha Womans University, Seoul 120-750 (Korea, Republic of); RamIrez, Solange V.; Boogert, A. C. Adwin [NASA Exoplanet Science Institute, California Institute of Technology, Mail Stop 100-22, Pasadena, CA 91125 (United States); Sellgren, Kris [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Arendt, Richard G. [CRESST/UMBC/GSFC, Code 665, NASA/Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Robitaille, Thomas P.; Smith, Howard A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Schultheis, Mathias [Observatoire de Besancon, 41bis, avenue de l'Observatoire, 25000 Besancon (France); Cotera, Angela S. [SETI Institute, 515 North Whisman Road, Mountain View, CA 94043 (United States); Stolovy, Susan R., E-mail: deokkeun@ewha.ac.kr [Spitzer Science Center, California Institute of Technology, Mail Code 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2011-08-01

134

Infrared and Kinematic Properties of the Substellar Object G 196-3 B  

NASA Astrophysics Data System (ADS)

We report unusual near- and mid-infrared photometric properties of G 196-3 B, the young substellar companion at 16'' from the active M2.5-type star G 196-3 A, using data taken with the IRAC and MIPS instruments onboard Spitzer. G 196-3 B shows markedly redder colors at all wavelengths from 1.6 up to 24 ?m than expected for its spectral type, which is determined at L3 from optical and near-infrared spectra. We discuss various physical scenarios to account for its reddish nature and conclude that a low-gravity atmosphere with enshrouded upper atmospheric layers and/or a warm dusty disk/envelope provides the most likely explanations, the two of them consistent with an age in the interval 20-300 Myr. We also present new and accurate separate proper motion measurements for G 196-3 A and B confirming that both objects are gravitationally linked and share the same motion within a few mas yr-1. After integration of the combined spectrophotometric spectral energy distributions, we obtain the result that the difference in the bolometric magnitudes of G 196-3 A and B is 6.15 ± 0.10 mag. Kinematic consideration of the Galactic space motions of the system for distances in the interval 15-30 pc suggests that the pair is a likely member of the Local Association and that it lies near the past positions of young star clusters like ? Persei less than 85 Myr ago, where the binary might have originated. At these young ages, the mass of G 196-3 B would be in the range 12-25 M Jup, close to the frontier between planets and brown dwarfs.

Zapatero Osorio, M. R.; Rebolo, R.; Bihain, G.; Béjar, V. J. S.; Caballero, J. A.; Álvarez, C.

2010-06-01

135

Chandra Observations of Faint LMXB's  

NASA Technical Reports Server (NTRS)

There exists a group of persistently faint galactic X-ray sources that based on their location in the galaxy, high Lx/Lopt, association with X-ray bursts, and absence of X-ray pulsations are thought to be low-mass X-ray binaries (LMXBs). We present results from Chandra observations for 7 of these systems: 1708-409, 1711-339, 1735-269, 1736-297, 1746-331, 1746.7-3224, and 1812-12. Improved locations for all sources, excluding 1736-297 and 1746-331 (which were not detected) are presented. Our observations are consistent with previously reported transient behavior of 1736-297, 1746-331, and 1711-339 (which we detect in one of two observations). Energy and power spectra are presented for 1735-269, 1711-339, and 1746.7-3224. The energy spectra are hard, consistent with typical faint LMXB spectra. Further, we present a newly discovered source, a very faint, soft, source, separated by 2.7' from 1746.7-3224.

Wilson, Colleen A.; Patel, S. K.; Kouveliotou, C.; vanderKlis, M.; Belloni, T.; Lewin, W. H. G.; Six, N. Frank (Technical Monitor)

2002-01-01

136

WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF YOUNG STELLAR OBJECTS IN THE WESTERN CIRCINUS MOLECULAR CLOUD  

SciTech Connect

The Wide-field Infrared Survey Explorer has uncovered a population of young stellar objects (YSOs) in the Western Circinus molecular cloud. Images show the YSOs to be clustered into two main groups that are coincident with dark filamentary structure in the nebulosity. Analysis of photometry shows numerous Class I and II objects. The locations of several of these objects are found to correspond to known dense cores and CO outflows. Class I objects tend to be concentrated in dense aggregates, and Class II objects more evenly distributed throughout the region.

Liu, Wilson M.; Fajardo-Acosta, Sergio [Infrared Processing and Analysis Center, California Institute of Technology, MC 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Padgett, Deborah L. [Spitzer Science Center, California Institute of Technology, MC 314-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Leisawitz, David; Koenig, Xavier P., E-mail: wliu@ipac.caltech.edu [NASA Goddard Space Flight Center, Code 605, Greenbelt, MD 20771 (United States)

2011-05-20

137

Far Infrared Water Line Emission in the Environment of Class 0 Objects  

NASA Astrophysics Data System (ADS)

We have conducted with ISO-LWS a study of the far infrared line emission of a sample of 17 Class 0 objects and their associated outflows. At variance with more evolved young stars, such as Class I and pre-main sequence stars, the investigated spectra show a copious molecular emission in form of CO, H2O and, to a minor extent, OH transitions. Our analysis demonstrates that the bulk of the emission arises from very small, dense and warm regions, where the ambient gas is heated by non-dissociative shocks, associated with the high energetic outflows characterizing this early phase of the star formation. Wherever gas phase water has been observed, large abundances are commonly estimated, with values which appear to be correlated with the gas temperature. OI, CO and H2O contribute rough equally the whole line luminosity, indicating that a strongly prevailing cooling channel does not exist. These results are however still not conclusive, given the poor statistics and the large uncertainties associated with the water abundance determinations. In this contribution we will show how the FIRST instrumental capabilities are well suited to put firm conclusions on these questions.

Giannini, T.; Nisini, B.; Lorenzetti, D.

2001-07-01

138

Infrared spectroscopy with multivariate analysis to interrogate endometrial tissue: a novel and objective diagnostic approach  

PubMed Central

Background: Endometrial cancer is the most common gynaecological malignancy in the United Kingdom. Diagnosis currently involves subjective expert interpretation of highly processed tissue, primarily using microscopy. Previous work has shown that infrared (IR) spectroscopy can be used to distinguish between benign and malignant cells in a variety of tissue types. Methods: Tissue was obtained from 76 patients undergoing hysterectomy, 36 had endometrial cancer. Slivers of endometrial tissue (tumour and tumour-adjacent tissue if present) were dissected and placed in fixative solution. Before analysis, tissues were thinly sliced, washed, mounted on low-E slides and desiccated; 10 IR spectra were obtained per slice by attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy. Derived data was subjected to principal component analysis followed by linear discriminant analysis. Post-spectroscopy analyses, tissue sections were haematoxylin and eosin-stained to provide histological verification. Results: Using this approach, it is possible to distinguish benign from malignant endometrial tissue, and various subtypes of both. Cluster vector plots of benign (verified post-spectroscopy to be free of identifiable pathology) vs malignant tissue indicate the importance of the lipid and secondary protein structure (Amide I and Amide II) regions of the spectrum. Conclusion: These findings point towards the possibility of a simple objective test for endometrial cancer using ATR-FTIR spectroscopy. This would facilitate earlier diagnosis and so reduce the morbidity and mortality associated with this disease.

Taylor, S E; Cheung, K T; Patel, I I; Trevisan, J; Stringfellow, H F; Ashton, K M; Wood, N J; Keating, P J; Martin-Hirsch, P L; Martin, F L

2011-01-01

139

A Search for Optically Faint GEO Debris  

NASA Technical Reports Server (NTRS)

Existing optical surveys for debris at geosynchronous orbit (GEO) have been conducted with meter class telescopes, which have detection limits in the range of 18th-19th magnitude. We report on a new search for optically faint debris at GEO using the 6.5-m Magellan 1 telescope Walter Baade at Las Campanas Observatory in Chile. Our goal is to go as faint as possible and characterize the brightness distribution of debris fainter than R = 20th magnitude, corresponding to a size smaller than 10 cm assuming an albedo of 0.175. We wish to compare the inferred size distribution for GEO debris with that for LEO debris. We describe results obtained during 9.4 hours of observing time during 25-27 March 2011. We used the IMACS f/2 instrument, which has a mosaic of 8 CCDs, and a field of view of 30 arc-minutes in diameter. This is the widest field of view of any instrument on either Magellan telescope. All observations were obtained through a Sloan r filter. The limiting magnitude for 5 second exposures is estimated to be fainter than 22. With this small field of view and the limited observing time, our objective was to search for optically faint objects from the Titan 3C Transtage (1968-081) fragmentation in 1992. Eight debris pieces and the parent rocket body are in the Space Surveillance Network public catalog. We successfully tracked two cataloged pieces of Titan debris (SSN # 25001 and 33519) with the 6.5-m telescope, followed by a survey for objects on similar orbits but with a spread in mean anomaly. To detect bright objects over a wider field of view (1.6x1.6 degrees), we observed the same field centers at the same time through a similar filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American Observatory, Chile. We will describe our experiences using Magellan, a telescope never used previously for orbital debris research, and our initial results.

Seitzer, Patrick; Lederer, Susan M.; Barker, Edwin S.; Cowardin, Heather; Abercromby, Kira J.; ilha, Jiri

2011-01-01

140

Ambient and Cryogenic Alignment Verification and Performance of the Infrared Multi-Object Spectrometer  

NASA Technical Reports Server (NTRS)

The Infrared Multi-Object Spectrometer (IRMOS) is a facility instrument for the Kitt Peak National Observatory 4 and 2.1 meter telescopes. IRMOS is a near-IR (0.8 - 2.5 micron) spectrometer with low- to mid-resolving power (R = 300 - 3000). IRMOS produces simultaneous spectra of approximately 100 objects in its 2.8 x 2.0 arc-min field of view using a commercial Micro Electro-Mechanical Systems (MEMS) Digital Micro-mirror Device (DMD) from Texas Instruments. The IRMOS optical design consists of two imaging subsystems. The focal reducer images the focal plane of the telescope onto the DMD field stop, and the spectrograph images the DMD onto the detector. We describe ambient breadboard subsystem alignment and imaging performance of each stage independently, and the ambient and cryogenic imaging performance of the fully assembled instrument. Interferometric measurements of subsystem wavefront error serve to venfy alignment, and are accomplished using a commercial, modified Twyman-Green laser unequal path interferometer. Image testing provides further verification of the optomechanical alignment method and a measurement of near-angle scattered light due to mirror small-scale surface error. Image testing is performed at multiple field points. A mercury-argon pencil lamp provides spectral lines at 546.1 nm and 1550 nm, and a CCD camera and IR camera are used as detectors. We use commercial optical modeling software to predict the point-spread function and its effect on instrument slit transmission and resolution. Our breadboard test results validate this prediction. We conclude with an instrument performance prediction for first light.

Connelly, Joseph A.; Ohl, Raymond G.; Mink, Ronald G.; Mentzell, J. Eric; Saha, Timo T.; Tveekrem, June L.; Hylan, Jason E.; Sparr, Leroy M.; Chambers, V. John; Hagopian, John G.

2003-01-01

141

A Search for Faint, Red Quasars: An Early Status Report.  

NASA Astrophysics Data System (ADS)

The study of the luminosity function of quasars and its evolution over cosmic time has been bedeviled with selection effects. Selection at purely optical wavelengths, for example, overlooks most heavily obscured sources - and will miss objects with redshifts so high that the interstellar medium is still largely neutral and Lyman alpha emission is redshifted out of the optical region of the spectrum. We have found that selection using X-rays yields more quasars per square degree down to a given optical magnitude than any other selection technique employed to date. We present the preliminary results of a pilot X-ray, infrared and optical search to identify - and begin to study - the nature of the missing population of faint red quasars in 3 ChaMP X-ray fields. Our AGN catalog from these fields was originally selected based on coincidence of hard-X-ray (Chandra) and near-IR point sources. To locate the red quasars, we have further selected a number of candidates with J<22 mag and Ks <20.3 mag for follow-up infrared spectroscopy, using the criteria J-K<1.5 and r'-Ks<4 ? similar to the color criteria proposed and used successfully by Glikman et al. Using IR slit spectroscopy, these authors found that ˜50% of their (much brighter) candidates, selected in this manner, turn out to be obscured quasars. Our near-IR photometric observations, (taken with the ISPI camera, which gives a 100-square-arcminute FOV on the 4m Blanco telescope at Cerro Tololo) are believed to be the deepest so far made with this instrument. This set of pilot data will serve as a prototype for more extensive observations being planned with the NEWFIRM camera, which will provide a FOV four times that of ISPI. The next step is to obtain spectroscopy with an 8m-class telescope.

Perez, L. M.; Smith, M. G.; Wilkes, B. J.; Green, P. J.; Mossman, A.; Kim, M.; Jannuzi, B. T.; Barkhouse, W. A.; Silverman, J. D.; Smith, P. S.; Norman, D.; Kim, D.-W.

2005-12-01

142

Fainting  

MedlinePLUS

... severely dehydrated ) Standing up very suddenly from a lying position Less common but more serious reasons for ... avoid or change them. Get up from a lying or seated position slowly. If having blood drawn ...

143

A substation infrared temperature monitoring and warning system with object separation and image registration  

Microsoft Academic Search

To find the defects of the apparatus in a substation in the early stage, an infrared temperature monitoring and warning system is established. This system can monitor the electrical equipment automatically the movement condition. The systemic circulation gathers the transformer substation electrical equipment the infrared imagery, the extraction goal equipment temperature information, and with the history database creation connection, the

Lihua Lin; Dongmei Wu; Jian Liu; Xinghua Zhang

2010-01-01

144

Near-infrared integral field spectroscopy of massive young stellar objects  

NASA Astrophysics Data System (ADS)

We present medium-resolution (R ? 5300) K-band integral field spectroscopy of six massive young stellar objects (MYSOs). The targets are selected from the Red MSX Source (RMS) survey, and we used the ALTAIR adaptive optics assisted Near-Infrared Integral Field Spectrometer (NIFS) mounted on the Gemini North telescope. The data show various spectral line features including Br?, CO, H2 and He I. The Br? line is detected in emission in all objects with vFWHM ˜ 100-200 km s-1. V645 Cyg shows a high-velocity P-Cygni profile between -800 and -300 km s-1. We performed three-dimensional spectroastrometry to diagnose the circumstellar environment in the vicinity of the central stars using the Br? line. We measured the centroids of the velocity components with sub-mas precision. The centroids allow us to discriminate the blueshifted and redshifted components in a roughly east-west direction in both IRAS 18151-1208 and S106 in Br?. This lies almost perpendicular to observed larger scale outflows. We conclude, given the widths of the lines and the orientation of the spectroastrometric signature, that our results trace a disc wind in both IRAS 18151-1208 and S106. The CO ? = 2-0 absorption lines at low J transitions are detected in IRAS 18151-1208 and AFGL 2136. We analysed the velocity structure of the neutral gas discs, which we find to have nearly Keplerian motions. In IRAS 18151-1208, the absorption centroids of the blueshifted and redshifted components are separated in a direction of north-east to south-west, nearly perpendicular to that of the larger scale H2 jet. The position-velocity relations of these objects can be reproduced with central masses of 30 M? for IRAS 18151-1208 and 20 M? for AFGL 2136. We also detect CO ? = 2-0 bandhead emission in IRAS 18151-1208, S106 and V645 Cyg. The results can be fitted reasonably with a Keplerian rotation model, with masses of 15, 20 and 20 M?, respectively. These results for a sample of MYSOs can be explained with disc and outflow models and support the hypothesis of massive star formation via mass accretion through discs as is the case for lower mass counterparts.

Murakawa, K.; Lumsden, S. L.; Oudmaijer, R. D.; Davies, B.; Wheelwright, H. E.; Hoare, M. G.; Ilee, J. D.

2013-11-01

145

Searching for Optically Faint GEO Debris  

NASA Technical Reports Server (NTRS)

We report on results from a search for optically faint debris (defined as R > 20th magnitude, or smaller than 10 cm assuming an albedo of 0.175)) at geosynchronous orbit (GEO) using the 6.5-m Magellan telescope "Walter Baade" at Las Campanas Observatory in Chile. Our goal is to characterize the brightness distribution of debris to the faintest limiting magnitude possible. Our data was obtained during 6 hours of observing time during the photometric nights of 26 and 27 March 2011 with the IMACS f/2 instrument, which has a field of view (fov) of 0.5 degrees in diameter. All observations were obtained through a Sloan r filter, and calibrated by observations of Landolt standard stars. Our primary objective was to search for optically faint objects from one of the few known fragmentations at GEO: the Titan 3C Transtage (1968-081) fragmentation in 1992. Eight debris pieces and the parent rocket body are in the Space Surveillance Network public catalog. We successfully tracked two cataloged pieces of Titan debris with the 6.5-m telescope, followed by a survey for unknown objects on similar orbits but with different mean anomalies. To establish the bright end of the debris population, calibrated observations were acquired on the same field centers, telescope rates, and time period with a similar filter on the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American Observatory, Chile. We will show the calibrated brightness distributions from both telescopes, and compare the observed brightness distributions with that predicted for various population models of debris of different sizes.

Seitzer, Patrick; Lederer, Susan M.; Abercromby, Kira J.; Barker, Edwin S.; Burkhardt, Andrew; Cowardin, Heather; Krisko, Paula; Silha, Jiri

2012-01-01

146

NEAR-INFRARED SPECTROSCOPY OF INFRARED-EXCESS STELLAR OBJECTS IN THE YOUNG SUPERNOVA REMNANT G54.1+0.3  

SciTech Connect

We present the results of broadband near-infrared spectroscopic observations of the recently discovered mysterious stellar objects in the young supernova remnant G54.1+0.3. These objects, which show significant mid-infrared-excess emission, are embedded in a diffuse loop structure of {approx}1' in radius. Their near-infrared spectra reveal characteristics of late O- or early B-type stars with numerous H and He I absorption lines, and we classify their spectral types to be between O9 and B2 based on an empirical relation derived here between the equivalent widths of the H lines and stellar photospheric temperatures. The spectral types, combined with the results of spectral energy distribution fits, constrain the distance to the objects to be 6.0 {+-} 0.4 kpc. The photometric spectral types of the objects are consistent with those from the spectroscopic analyses, and the extinction distributions indicate a local enhancement of matter in the western part of the loop. If these objects originate via triggered formation by the progenitor star of G54.1+0.3, then their formations likely began during the later evolutionary stages of the progenitor, although a rather earlier formation may still be possible. If the objects and the progenitor belong to the same cluster of stars, then our results constrain the progenitor mass of G54.1+0.3 to be between 18 and {approx}35 M{sub Sun} and suggest that G54.1+0.3 was either a Type IIP supernova or, with a relatively lower possibility, Type Ib/c from a binary system.

Kim, Hyun-Jeong; Koo, Bon-Chul [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Moon, Dae-Sik, E-mail: hjkim@astro.snu.ac.kr, E-mail: koo@astro.snu.ac.kr, E-mail: moon@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

2013-09-01

147

Saturn's ring and nearby faint satellites  

NASA Technical Reports Server (NTRS)

Observations of Saturn's rings during passage of the Earth through the ring plane, coupled with those of others, suggest a ring thickness of 1.3 plus or minus 0.3 km. The wide disparity in the optical depth of Cassini's division found by other investigators is resolved, and for conservative isotropic single scattering, a normal optical depth for Cassini's division of 0.060 plus or minus 0.006 is obtained. We find the mean normal optical depth of ring C to be 0.074 plus or minus 0.007. Analysis of all available observations of faint objects near Saturn indicates the presence of at least one previously undiscovered satellite of Saturn. The orbit for Janus determined by Dollfus is supported. These satellites may be major members of an extended ring.

Fountain, J. W.; Larson, S. M.

1978-01-01

148

Optical and Near Infrared Study of the Cepheus E Outflow, a Very Low Excitation Object  

NASA Technical Reports Server (NTRS)

In this study, we explore the link between the physical properties of the outflow as determined from optical imaging and spectroscopy, and compare these results with those obtained from observations in the near infrared.

Noreiga-Crespo, A.; Ayala, S.; Garnavich, P.; Curiel, S.; Raga, A.; Bohm, K.; Raymond, J.

2000-01-01

149

A spherical lamellar grating interferometer for airborne astronomical observations of far infrared objects  

NASA Technical Reports Server (NTRS)

A lamellar grating has been developed to be used for very far infrared observations on the airborne observatory. The design characteristics and performance during laboratory testing and initial observations of Jupiter at wavelengths between 50 and 500 microns are presented.

Pipher, J. L.; Savedoff, M. P.; Duthie, J. G.

1976-01-01

150

Near-Infrared Rotational Variability in Comet-Asteroid Transition Object 944 Hidalgo  

NASA Astrophysics Data System (ADS)

Dynamical arguments indicate that 944 Hidalgo is most likely an extinct or dormant comet. Hidalgo's Tisserand invariant (T = 2.07) suggests strongly that this object came either from the Kuiper belt or the Oort cloud (e.g., Weissman et al. 2002). We obtained low-resolution near-infrared spectra in the 0.8-2.4 micron region on UT Oct 22, 23, Nov 19 and Dec 11, 2004, using the SpeX instrument on NASA's Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii (Oct. and Nov.) and the NICS instrument on the Telescopio Nazionale Galileo (TNG) on La Palma, Spain (Dec.). Our reflectance spectra show a range of slopes. To characterize these slope differences, we normalized each spectrum to 1.0 reflectance at 1.25 microns and measured the reflectance at 2.2 microns. These values are listed in the table for the seven spectra obtained on the two dates when we have temporal coverage, Oct 22 and 23. The uncertainty in each reflectance value is ± 3%. Hidalgo's rotational light curve has a period of 10.06 hours and amplitudes ranging from 0.31 to 0.6 magnitudes in the visible (Harris and Warner 2006, Minor Planet Center). We define the time of our first observation on Oct. 22 as zero rotational phase and give the other six phases in the table. The table shows a systematic temporal variation of the spectral slope consistent with the rotational period. Based on an unpublished visible light curve obtained 10 days earlier (C. Hergenrother personal communication) we determine that one of the small ends of Hidalgo corresponds to our "reddest” spectrum (phase 0.36) while one of the broad sides has the flattest spectrum (phase 0.77).
Reflectance at 2.2 ?m1.261.311.391.361.271.241.23
Rotational Phase0.00.140.360.590.620.720.77

Campins, Humberto; Licandro, J.; Fernandez, Y.; Hergenrother, C.; Ziffer, J.; Emery, J.; Cruikshank, D.; Pinilla-Alonso, N.

2006-09-01

151

Infrared mergers and infrared quasi-stellar objects with galactic winds - III. Mrk 231: an exploding young quasi-stellar object with composite outflow\\/broad absorption lines (and multiple expanding superbubbles)  

Microsoft Academic Search

We present a study of outflow (OF) and broad absorption line (BAL) systems in Mrk 231, and in similar infrared (IR) quasi-stellar objects (QSOs). This study is based mainly on one-dimensional and two-dimensional spectroscopy (obtained at La Palma\\/William Herschel Telescope, Hubble Space Telescope, International Ultraviolet Explorer, European Southern Observatory\\/New Technology Telescope, Kitt Peak National Observatory, Apache Point Observatory and Complejo

S. Lípari; R. Terlevich; W. Zheng; B. Garcia-Lorenzo; S. F. Sanchez; M. Bergmann

2005-01-01

152

A Ground-Based Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the Rho Ophiuchi Cloud Core  

NASA Astrophysics Data System (ADS)

Results of a comprehensive, new, ground-based mid-infrared imaging survey of the young stellar population of the ? Ophiuchi cloud are presented. Data were acquired at the Palomar 5-m and at the Keck 10-m telescopes with the MIRLIN and LWS instruments, at 0.5'' and 0.25'' resolutions, respectively. Of 172 survey objects, 85 were detected. A plot of the frequency distribution of the detected objects with SED spectral slope shows that YSOs spend ˜ 3 × 105 yr in the Flat Spectrum phase, clearing out their remnant infall envelopes. Mid-infrared variability is found among a significant fraction of the surveyed objects and is found to occur for all SED classes with optically thick disks. Large amplitude near-infrared variability, also found for all SED classes with optically thick disks, seems to occur with somewhat higher frequency at the earlier evolutionary stages. The highly variable value of K-band veiling that a single source can exhibit in any of the SED classes in which active disk accretion can take place is striking, and is direct observational evidence for highly time-variable accretion activity in disks. Finallly, by comparing mid-infrared vs. near-infrared excesses in a subsample with well-determined effective temperatures and extinction values, disk clearing mechanisms are explored. Financial support for this project through NSF grants AST 00-96087 (CAREER), AST 97-53229 (POWRE), and AST 02-06146 is gratefully acknowledged. MB further thanks the NASA/ASEE Summer Faculty Fellowship program at JPL, that made this work possible.

Barsony, M.; Ressler, M. E.; Marsh, K. A.

2004-12-01

153

Detection of buried objects by fusing dual-band infrared images  

SciTech Connect

We have conducted experiments to demonstrate the enhanced detectability of buried land mines using sensor fusion techniques. Multiple sensors, including visible imagery, infrared imagery, and ground penetrating radar (GPR), have been used to acquire data on a number of buried mines and mine surrogates. Because the visible wavelength and GPR data are currently incomplete. This paper focuses on the fusion of two-band infrared images. We use feature-level fusion and supervised learning with the probabilistic neural network (PNN) to evaluate detection performance. The novelty of the work lies in the application of advanced target recognition algorithms, the fusion of dual-band infrared images and evaluation of the techniques using two real data sets.

Clark, G.A.; Sengupta, S.K.; Sherwood, R.J.; Buhl, M.R.; Schaich, P.C.; Kane, R.J.; Barth, M.J.; Fields, D.J.; Carter, M.R.

1993-11-01

154

Wide-Field Infrared Survey Explorer Observations of Young Stellar Objects in the Lynds 1509 Dark Cloud in Auriga  

NASA Astrophysics Data System (ADS)

The Wide-Field Infrared Survey Explorer (WISE) has uncovered a striking cluster of young stellar object (YSO) candidates associated with the L1509 dark cloud in Auriga. The WISE observations, at 3.4 ?m, 4.6 ?m, 12 ?m, and 22 ?m, show a number of objects with colors consistent with YSOs, and their spectral energy distributions suggest the presence of circumstellar dust emission, including numerous Class I, flat spectrum, and Class II objects. In general, the YSOs in L1509 are much more tightly clustered than YSOs in other dark clouds in the Taurus-Auriga star forming region, with Class I and flat spectrum objects confined to the densest aggregates, and Class II objects more sparsely distributed. We estimate a most probable distance of 485-700 pc, and possibly as far as the previously estimated distance of 2 kpc.

Liu, Wilson M.; Padgett, Deborah L.; Terebey, Susan; Angione, John; Rebull, Luisa M.; McCollum, Bruce; Fajardo-Acosta, Sergio; Leisawitz, David

2014-06-01

155

The Near-Infrared Camera and Multi-Object Spectrometer Ultra Deep Field: Observations, Data Reduction, and Galaxy Photometry  

Microsoft Academic Search

This paper describes the observations and data reduction techniques for the version 2.0 images and catalog of the Near-Infrared Camera and Multi-Object Spectrometer Ultra Deep Field (NICMOS UDF) Treasury program. All sources discussed in this paper are based on detections in the combined NICMOS F110W and F160W bands only. The NICMOS images are drizzled to 0.09\\

Rodger I. Thompson; Garth Illingworth; Rychard Bouwens; Mark Dickinson; Daniel Eisenstein; Xiaohui Fan; Marijn Franx; Adam Riess; Marcia J. Rieke; Glenn Schneider; Elizabeth Stobie; Sune Toft; Pieter van Dokkum

2005-01-01

156

Faint Rings and Things According to Cassini  

Microsoft Academic Search

During Saturn Orbit Insertion and the months surrounding that event, Cassini imaged various ring structures having low optical depth. These include the broad diffuse E ring, the narrower G ring, the contorted F ring, diffuse ringlets within the Encke gap and a very faint sheet lying between the A and F rings. We have also discovered a very faint, narrow

M. M. Hedman; J. A. Burns; C. D. Murray; M. S. Tiscareno; J. N. Cuzzi; C. C. Porco; H. Dones; A. Brahic; C. Ferrari

2004-01-01

157

Objective Estimation of Tropical Cyclone Wind Structure from Infrared Satellite Data  

Microsoft Academic Search

Geostationary infrared (IR) satellite data are used to provide estimates of the symmetric and total low-level wind fields in tropical cyclones, constructed from estimations of an azimuthally averaged radius of maximum wind (RMAX), a symmetric tangential wind speed at a radius of 182 km (V182), a storm motion vector, and the maximum intensity (VMAX). The algorithm is derived using geostationary

Kimberly J. Mueller; Mark DeMaria; John Knaff; James P. Kossin; Thomas H. Vonder Haar

2006-01-01

158

Objectively Mapping the East Australia Current from six years of Infrared Imagery and Satellite Altimetry  

Microsoft Academic Search

Surface currents are mapped from multiple daily sequential infrared satellite images using the Maximum Cross Correlation (MCC) technique for six years between 1993 and 1999 in the region of the East Australian Current (EAC). The resulting surface velocities are combined with coincident satellite altimetry heights using a stream function and an optimum interpolation (OI) technique. The resulting merged surface current

W. Emery; M. Bowen; J. Wilkin

2002-01-01

159

IRAS(Infrared Astronomy Satellite) Colors of VLA (Very Large Array) Identified Objects in the Galaxy.  

National Technical Information Service (NTIS)

Infrared Astronomy Satellite (IRAS) sources found within 4 degrees of l = 125 deg, b = 2 deg on the 3rd HCON 60 micrometer Sky Brightness Images were observed at the Very Large Array (VLA). Regions were to be identified where massive stars are forming by ...

M. Fich S. Terebey

1987-01-01

160

Gemini Mid-Infrared Imaging of Massive Young Stellar Objects in NGC 3576  

Microsoft Academic Search

We present a mid-infrared study of NGC 3576. The high-resolution images were\\u000ataken at the Gemini South Observatory through narrow and broad band filters\\u000acentered between 7.9 micron and 18 micron. The nearly diffraction limited\\u000aimages show IRS 1 resolved into 4 sources for the first time in the 10 micron\\u000aband. The positions of the sources are coincident with

C. L. Barbosa; A. Damineli; R. D. Blum; P. S. Conti

2003-01-01

161

A Search For Faint Companions of ? Eridani and ? Pictoris  

NASA Astrophysics Data System (ADS)

Deep, coronographic J-band images of the IR-excess star ? Eridani show no faint companions within 18" (60 AU) of the star. In particular, no companions were noted at the position of the Greaves et. al (1998) submilimeter excess located at ? (J 2000) = 03 32 57.25, ? (J2000) = -09 27 36.0. Although one J = 18.3 object was detected 17" from the star, it does not share ? Eridani's proper motion and is almost certainly a background object. Similarly, non-coronographic images of ? Pictoris showed no companions within 20" (380 AU) of the region of submilimeter excess (? (J2000) = 05 46 57, ? (J2000) = 51 03 38), previously identified by Holland et al. (1998) as being a likely location for a faint companion. This work was supported by a NASA Origins grant to UCLA.

Kaisler, D.; Mccarthy, C. M.; Zuckerman, B.; Becklin, E. E.

2000-05-01

162

High-sensitivity and cost-effective system for infrared imaging of concealed objects in dynamic mode  

NASA Astrophysics Data System (ADS)

Novel, cost-efficient, and highly-sensitive IR imaging systems play an important role in homeland security functions. Technical limitations in the areas of sensitivity, contrast ratio, bandwidth and cost continue to constrain imaging capabilities. We have designed and prototyped a compact computer-piloted high sensitivity infrared imaging system. The device consists of infrared optics, cryostat, low-noise pre-amplifier, Analog-to-Digital hardware, feedback electronics, and unique image processing software. Important advantages of the developed system are: (i) Eight electronic channels are available for simultaneous registration of IR and visible images in multiple spectral ranges, (ii) Capability of real-time analysis such as comparing the "sensed" image with "reference" images from a database, (iii) High accuracy temperature measurement of multiple points on the image by referencing the radiation intensity from the object to a black body model, (iv) Image generation by real-time integration of images from multiple sensors operating from the visible to the terahertz range. The device was tested with a liquid-nitrogen-cooled, single-pixel HgCdTe detector for imaging in 8-12 microns range. The demonstrated examples of infrared imaging of concealed objects in static and dynamic modes include a hammer (metal head and wooden handle), plastic imitator of handguns hidden under clothes, powder in an envelope, and revealing complex wall structures under decorative plaster.

Gordiyenko, E.; Yefremenko, V.; Pearson, J.; Bader, S. D.; Novosad, V.

2005-05-01

163

Using near-infrared spectroscopy to assess neural activation during object processing in infants  

PubMed Central

The capacity to represent the world in terms of numerically distinct objects (i.e., object individuation) is a milestone in early cognitive development and forms the foundation for more complex thought and behavior. Over the past 10 to 15 yr, infant researchers have expended a great deal of effort to identify the origins and development of this capacity. In contrast, relatively little is known about the neural mechanisms that underlie the ability to individuate objects, in large part because there are a limited number of noninvasive techniques available to measure brain functioning in human infants. Recent research suggests that near-IR spectroscopy (NIRS), an optical imaging technique that uses relative changes in total hemoglobin concentration and oxygenation as an indicator of neural activation, may be a viable procedure for assessing the relation between object processing and brain function in human infants. We examine the extent to which increased neural activation, as measured by NIRS, could be observed in two neural areas known to be involved in object processing, the primary visual cortex and the inferior temporal cortex, during an object processing task. Infants aged 6.5 months are presented with a visual event in which two featurally distinct objects emerge successively to opposite sides of an occluder and neuroimaging data are collected. As predicted, increased neural activation is observed in both the primary visual and inferior cortex during the visual event, suggesting that these neural areas support object processing in the young infant. The outcome has important implications for research in cognitive development, developmental neuroscience, and optical imaging.

Wilcox, Teresa; Bortfeld, Heather; Woods, Rebecca; Wruck, Eric; Boas, David A.

2006-01-01

164

PESSTO monitoring of SN 2012hn: further heterogeneity among faint Type I supernovae  

NASA Astrophysics Data System (ADS)

We present optical and infrared monitoring data of SN 2012hn collected by the Public European Southern Observatory Spectroscopic Survey for Transient Objects. We show that SN 2012hn has a faint peak magnitude (MR ˜ -15.65) and shows no hydrogen and no clear evidence for helium in its spectral evolution. Instead, we detect prominent Ca II lines at all epochs, which relates this transient to previously described `Ca-rich' or `gap' transients. However, the photospheric spectra (from -3 to +32 d with respect to peak) of SN 2012hn show a series of absorption lines which are unique and a red continuum that is likely intrinsic rather than due to extinction. Lines of Ti II and Cr II are visible. This may be a temperature effect, which could also explain the red photospheric colour. A nebular spectrum at +150 d shows prominent Ca II, O I, C I and possibly Mg I lines which appear similar in strength to those displayed by core-collapse supernovae (SNe). To add to the puzzle, SN 2012hn is located at a projected distance of 6 kpc from an E/S0 host and is not close to any obvious star-forming region. Overall SN 2012hn resembles a group of faint H-poor SNe that have been discovered recently and for which a convincing and consistent physical explanation is still missing. They all appear to explode preferentially in remote locations offset from a massive host galaxy with deep limits on any dwarf host galaxies, favouring old progenitor systems. SN 2012hn adds heterogeneity to this sample of objects. We discuss potential explosion channels including He-shell detonations and double detonations of white dwarfs as well as peculiar core-collapse SNe.

Valenti, S.; Yuan, F.; Taubenberger, S.; Maguire, K.; Pastorello, A.; Benetti, S.; Smartt, S. J.; Cappellaro, E.; Howell, D. A.; Bildsten, L.; Moore, K.; Stritzinger, M.; Anderson, J. P.; Benitez-Herrera, S.; Bufano, F.; Gonzalez-Gaitan, S.; McCrum, M. G.; Pignata, G.; Fraser, M.; Gal-Yam, A.; Le Guillou, L.; Inserra, C.; Reichart, D. E.; Scalzo, R.; Sullivan, M.; Yaron, O.; Young, D. R.

2014-01-01

165

Low creatine kinase is associated with a high population incidence of fainting  

Microsoft Academic Search

Objective  Vasoconstrictor capacity, skeletal muscle tone, and renal sodium retention are involved in the pathogenesis of fainting. As\\u000a muscle contractility and ion transport are highly energy-demanding processes, we hypothesized that a low activity of the energy-generating\\u000a enzyme creatine kinase (CK) is associated with a higher risk of fainting. The aim of this observational study was to explore\\u000a the association of vasovagal

Lizzy M. Brewster; Gideon Mairuhu; Karin Ganzeboom; Nynke van Dijk; Gert A. van Montfrans; Wouter Wieling

2009-01-01

166

Visible and infrared investigations of planet-crossing asteroids and outer solar system objects  

NASA Technical Reports Server (NTRS)

The project is supporting lightcurve photometry, colorimetry, thermal radiometry, and astrometry of selected asteroids. Targets include the planet-crossing population, particularly Earth approachers, which are believed to be the immediate source of terrestrial meteorites, future spacecraft targets, and those objects in the outer belt, primarily the Hilda and Trojan populations, that are dynamically isolated from the main asteroid belt. Goals include the determination of population statistics for the planet-crossing objects, the characterization of spacecraft targets to assist in encounter planning and subsequent interpretation of the data, a comparison of the collisional evolution of dynamically isolated Hilda and Trojan populations with the main belt, and the determination of the mechanism driving the activity of the distant object 2060 Chiron.

Tholen, David J.

1991-01-01

167

An optical and infrared study of the region surrounding Herbig-Haro objects 1 and 2  

NASA Technical Reports Server (NTRS)

Optical and near-IR observations of the environs of H-H objects 1 and 2 provide the basis for identifying a recently discovered radio continuum as the star responsible for powering the highly collimated mass outflow traced by these objects. Polarimetric observations show that the source (designated as VLA 1), located at the midpoint between HH 1 and 2, illuminates a biconical reflection nebula. It is suggested that VLA 1 is probably surrounded by an optically thick disk viewed edge on; an optical 'jet' emanates from the vicinity of HH 1 and is directed along the axis of the putative disk toward HH 1; its spectrum resembles that of HH 1 and other Herbig-Haro objects.

Strom, S. E.; Strom, K. M.; Grasdalen, G. L.; Sellgren, K.; Wolff, S.

1985-01-01

168

Visible and infrared investigations of planet-crossing asteroids and outer solar system objects  

NASA Astrophysics Data System (ADS)

The project is supporting lightcurve photometry, colorimetry, thermal radiometry, and astrometry of selected asteroids. Targets include the planet-crossing population, particularly Earth approachers, which are believed to be the immediate source of terrestrial meteorites, future spacecraft targets, and those objects in the outer belt, primarily the Hilda and Trojan populations, that are dynamically isolated from the main asteroid belt. Goals include the determination of population statistics for the planet-crossing objects, the characterization of spacecraft targets to assist in encounter planning and subsequent interpretation of the data, a comparison of the collisional evolution of dynamically isolated Hilda and Trojan populations with the main belt, and the determination of the mechanism driving the activity of the distant object 2060 Chiron.

Tholen, David J.

1991-10-01

169

The MYStIX YSO Catalog: The Dark Art of Finding Young Stellar Objects Via Infrared Excess Emission  

NASA Astrophysics Data System (ADS)

The MYStIX project (Massive Young stellar clusters Study in Infrared and X-rays) is compiling comprehensive catalogs of the stellar membership in ~20 Galactic massive star-forming regions (d = 0.4 to 3.6 kpc). MYStIX is the first project of its kind to study such a large sample of Galactic regions in parallel, employing a homogeneous set of multiwavelength data analysis techniques. Probable stellar members in each target region are identified using X-ray and/or infrared photometry via two pathways: (1) X-ray detections of young/massive stars with coronal activity/strong winds or (2) Infrared (IR) excess selection of young stellar objects (YSOs) with circumstellar disks and/or protostellar envelopes. In this contribution, we present the methodology and initial results of pathway (2), using Spitzer/IRAC, 2MASS, and UKIDSS imaging and photometry. Although IR excess selection of YSOs is well-trodden territory, MYStIX presents unique challenges. The target regions run the gamut from relatively nearby, lower-mass clusters in uncrowded fields located toward the outer Galaxy (e.g. NGC 2264, the Flame Nebula), to massive clusters located at greater distances along complicated, inner Galaxy sightlines (e.g. NGC 6357, M17). We have developed a new procedure combining IR spectral energy distribution fitting with IR color cuts and spatial clustering analysis to separate probable YSO members in each MYStIX target field from the myriad types of contaminating objects that resemble YSOs: extragalactic sources, evolved stars, PAH nebular knots, and even unassociated foreground/background YSOs. Applying this technique consistently across our target regions, we have produced a catalog comprising several thousand YSOs that can serve as the basis for follow-up studies of diverse phenomena related to massive cluster formation, including protostellar outflows, circumstellar disks, and triggered star formation.

Povich, Matthew S.; Kuhn, M.; Getman, K. V.; Feigelson, E.; Broos, P. S.; Townsley, L. K.; Naylor, T.

2013-01-01

170

Functional connectivity in the prefrontal cortex measured by near-infrared spectroscopy during ultrarapid object recognition  

NASA Astrophysics Data System (ADS)

Near-infrared spectroscopy (NIRS) is a developing technology for low-cost noninvasive functional brain imaging. With multichannel optical instruments, it becomes possible to measure not only local changes in hemoglobin concentrations but also temporal correlations of those changes in different brain regions which gives an optical analog of functional connectivity traditionally measured by fMRI. We recorded hemodynamic activity during the Go-NoGo task from 11 right-handed subjects with probes placed bilaterally over prefrontal areas. Subjects were detecting animals as targets in natural scenes pressing a mouse button. Data were low-pass filtered <1 Hz and cardiac/respiration/superficial layers artifacts were removed using Independent Component Analysis. Fisher's transformed correlations of poststimulus responses (30 s) were averaged over groups of channels unilaterally in each hemisphere (intrahemispheric connectivity) and the corresponding channels between hemispheres (interhemispheric connectivity). The hemodynamic response showed task-related activation (an increase/decrease in oxygenated/deoxygenated hemoglobin, respectively) greater in the right versus left hemisphere. Intra- and interhemispheric functional connectivity was also significantly stronger during the task compared to baseline. Functional connectivity between the inferior and the middle frontal regions was significantly stronger in the right hemisphere. Our results demonstrate that optical methods can be used to detect transient changes in functional connectivity during rapid cognitive processes.

Medvedev, Andrei V.; Kainerstorfer, Jana M.; Borisov, Sergey V.; Vanmeter, John

2011-01-01

171

Studying the inspection limits in detecting buried objects by using infrared thermography  

NASA Astrophysics Data System (ADS)

In Japan it happens that building parts made of concrete suddenly collapse to create obstacles to the traffic in tunnels, on highways and bridges. Thus, the safety issue has become a serious social problem. Therefore, the detection of hidden defects in concrete building constructions in order to prevent an accidental damage is the important application area for nondestructive testing (NDT) techniques. Until now, the inspection is typically performed by using a hammer that is subjective and takes too much time. Infrared thermography is a promising NDT technique that might help in the fast detection of invisible (hidden) defects. Transient, or active, thermal NDT requires external thermal stimulation of the defects under test by warming up or cooling down the defect surface. However, low-power and long heating is significantly affected by environmental conditions. Recent Japanese research in this area has been rather qualitative, i.e. without putting the accent on evaluating parameters of hidden defects. In this study, the experimental results are modeled and processed by using the thermal NDT package developed at the Tomsk Institute of Introscopy. This has allowed not only optimizing test parameters but also obtaining reasonable estimates of defect parameters for air-filled voids and inclusions in concrete. It is shown that MRTD values experimented by us are of a little help while evaluating detection limits.

Kamoi, Arao; Okamoto, Yoshizo; Vavilov, Vladimir P.

2003-04-01

172

Functional connectivity in the prefrontal cortex measured by near-infrared spectroscopy during ultrarapid object recognition  

PubMed Central

Near-infrared spectroscopy (NIRS) is a developing technology for low-cost noninvasive functional brain imaging. With multichannel optical instruments, it becomes possible to measure not only local changes in hemoglobin concentrations but also temporal correlations of those changes in different brain regions which gives an optical analog of functional connectivity traditionally measured by fMRI. We recorded hemodynamic activity during the Go-NoGo task from 11 right-handed subjects with probes placed bilaterally over prefrontal areas. Subjects were detecting animals as targets in natural scenes pressing a mouse button. Data were low-pass filtered <1 Hz and cardiac?respiration?superficial layers artifacts were removed using Independent Component Analysis. Fisher's transformed correlations of poststimulus responses (30 s) were averaged over groups of channels unilaterally in each hemisphere (intrahemispheric connectivity) and the corresponding channels between hemispheres (interhemispheric connectivity). The hemodynamic response showed task-related activation (an increase?decrease in oxygenated?deoxygenated hemoglobin, respectively) greater in the right versus left hemisphere. Intra- and interhemispheric functional connectivity was also significantly stronger during the task compared to baseline. Functional connectivity between the inferior and the middle frontal regions was significantly stronger in the right hemisphere. Our results demonstrate that optical methods can be used to detect transient changes in functional connectivity during rapid cognitive processes.

Medvedev, Andrei V.; Kainerstorfer, Jana M.; Borisov, Sergey V.; VanMeter, John

2011-01-01

173

Compact Far Infrared Emission from the Young Stellar Object IRAS 16293-2422.  

National Technical Information Service (NTIS)

High resolution far IR observations at 50 and 100 microns were made of the young stellar object (YSO), IRAS 16293-2422. The observations are part of a systematic high resolution study of nearby YSO's. The purpose is to obtain resolution in the far IR comp...

H. M. Butner N. J. Evans D. F. Lester L. G. Mundy P. M. Harvey

1989-01-01

174

Safe VISITOR: visible, infrared, and terahertz object recognition for security screening application  

Microsoft Academic Search

Security solutions with the purpose to detect hidden objects underneath the clothing of persons are desired in many environments. With the variety of application scenarios criteria like flexibility and mobility become more important. So, many developments trend to focus on cameras, which can image scenes from a distance. This new generation of tools will have the advantage of hidden operation,

T. May; G. Zieger; S. Anders; V. Zakosarenko; H.-G. Meyer; M. Schubert; M. Starkloff; M. Rößler; G. Thorwirth; U. Krause

2009-01-01

175

Objective Monitoring Method for African Rainfall Based on Meteosat VIS (Visible) and IR (Infrared) Images.  

National Technical Information Service (NTIS)

The integration of three-time daily pairs of Meteosat visible and IR images, plus three night-time IR-only images, through an objective procedure for determining rain/no-rain boundaries across the whole continent of Africa is described. Suitable bispectra...

E. C. Barrett G. Dsouza

1986-01-01

176

Investigation of small solar system objects with the space telescope  

NASA Technical Reports Server (NTRS)

The application of the space telescope (ST) to study small objects in the solar system in order to understand the birth and the early evolution of the solar system is discussed. The upper size limit of the small bodies is defined as approximately 5000 km and includes planetary satellites, planetary rings, asteroids, and comets.The use of the astronomical instruments aboard the ST, such as the faint object camera, ultraviolet and infrared spectrometers, and spectrophotometers, to study the small solar system objects is discussed.

Morrison, D.

1979-01-01

177

Visible and near-infrared colors of Transneptunian objects and Centaurs from the second ESO large program  

NASA Astrophysics Data System (ADS)

Aims: We investigate color properties and define or check taxonomic classifications of objects observed in our survey. Methods: All observations were performed between October 2006 and September 2007 at the European Southern Observatory 8 m Very Large Telescope, UT1 and UT2 at the Paranal Observatory in Chile. For visible photometry, we used the FORS1 instrument, and for near-infrared, ISAAC. Taxonomic classifications from the Barucci system were assigned using G-mode analysis. Results: We present photometric observations of 23 TNOs and Centaurs, nine of which have never been previously observed. Eighteen of these objects were assigned taxonomic classifications: six BB, four BR, two RR, and six that are given two or more categories due to insufficient data. Three objects that had been previously observed and classified, changed classes most likely due to surface variation: 26375 (1999 DE9), 28978 (Ixion), and 32532 (Thereus). Two objects, 47932 (2000 GN171) and 54598 (Bienor) had absolute magnitude values that were significantly different from previously published results, attributed to extreme lightcurve amplitudes. Based on observations at the European Southern Observatory, Chile under programs 178.C-0867 and 178.C-0036.

DeMeo, F. E.; Fornasier, S.; Barucci, M. A.; Perna, D.; Protopapa, S.; Alvarez-Candal, A.; Delsanti, A.; Doressoundiram, A.; Merlin, F.; de Bergh, C.

2009-01-01

178

Objectively Mapping the East Australia Current from six years of Infrared Imagery and Satellite Altimetry  

NASA Astrophysics Data System (ADS)

Surface currents are mapped from multiple daily sequential infrared satellite images using the Maximum Cross Correlation (MCC) technique for six years between 1993 and 1999 in the region of the East Australian Current (EAC). The resulting surface velocities are combined with coincident satellite altimetry heights using a stream function and an optimum interpolation (OI) technique. The resulting merged surface current maps are used to analyze the behavior of the EAC over this period of time. The MCC vectors are able to fill in valuable portions of the surface currents not well covered by those derived from altimetry alone. This is particularly true of the mean flow in the EAC, which was removed from the altimeter data when a mean sea surface height was taken out. In addition the MCC vectors interpolate between the widely spaced altimetric surface currents computed from the altimeter tracks making it possible to better resolve the strong mesoscale structure of the eddies in the EAC. The time series of merged surface currents clearly shows the propagation of mesoscale energy as bands of NW-SE highs and lows into the EAC region from the NE where it gives rise to the local eddy structure that is carried southward by the mean flow of the EAC. A series of more circular cy clonic and anticyclonic circulations form at about 32 S where the EAC separates from the coast. Spectra of the surface currents exhibit significant peaks at 115, 165 and 250 days as well as at the annual cycle with clear anisotropy between the east-west a d north-southn currents at both the 115 and 165 day peaks. The westward propagation was supported by an extended EOF analysis of the surface currents band-passed for periods between 90 and 180 days (to capture the main peaks at 115 and 160 days). Two propagating modes captured 50% of the variances and showed alongshore propagation while the next two modes showed a connection to the offshore-onshore propagation of mesoscale features.

Emery, W.; Bowen, M.; Wilkin, J.

179

The gas environment of the young stellar object GL 2591 studied by infrared spectroscopy  

NASA Technical Reports Server (NTRS)

High-resolution M band (4.6 microns) spectroscopy of GL 2591 is presented. Physical structures noted include an absorption feature with an outflow velocity of about 17 km/s, cold gas (identified with the core of the molecular cloud within which the object is embedded), and very broad C-12O lines formed in a neutral wind. The detection of hot low-velocity gas together with warm high-velocity gas suggests the scenario of a warm neutral wind accelerating from an accretion disk.

Mitchell, George F.; Curry, Charles; Maillard, Jean-Pierre; Allen, Mark

1989-01-01

180

The compact far infrared emission from the young stellar object IRAS 16293-2422  

NASA Technical Reports Server (NTRS)

High resolution far IR observations at 50 and 100 microns were made of the young stellar object (YSO), IRAS 16293-2422. The observations are part of a systematic high resolution study of nearby YSO's. The purpose is to obtain resolution in the far IR comparable to that at other wavelengths. Until recently, the high resolution that has been available in the far IR has been from either IRAS (angular resolution of approx 4 min) or the KAO using standard FIR photometry (approx 35 sec). With scanning techniques, it is possible to obtain 10 sec resolution on bright sources. Such a resolution is necessary to better determine the physical conditions of the YSO, and to compare with model of star formation. In order to better constrain the models for the source, the YSO was observed at both 50 and 100 microns on several flights in 1988 April from the KAO. Estimates are presented of the size both along the major and minor axis of the disk, as well as estimates of the dust temperature and 100 micron opacity for the YSO.

Butner, Harold M.; Evans, N. J., III; Lester, D. F.; Mundy, L. G.; Harvey, P. M.; Campbell, M. F.

1989-01-01

181

Robust detection of small infrared objects in maritime scenarios using local minimum patterns and spatio-temporal context  

NASA Astrophysics Data System (ADS)

Here, we describe a novel approach for small surface object detection with an onboard infrared (IR) camera working in maritime scenes. First, we propose a simple but effective tool called the local minimum patterns (LMP), which are theoretically the approximated coefficients of some stationary wavelet transforms, for single image background estimation. Second, potential objects are segmented by an adaptive threshold estimated from the saliency map, which is obtained by background subtraction. Using the LMP based wavelet transforms and the histogram of the saliency map, the threshold can be automatically determined by singularity analysis. Next, we localize potential objects by our proposed fast clustering algorithm, which, compared with popular K-Means, is much faster and less sensitive to noises. To make the surveillance system more reliable, we finally discuss how to integrate multiple cues, such as scene geometry constraints and spatio-temporal context, into detections by Bayesian inference. The proposed method has shown to be both effective and efficient by our extensive experiments on some challenging data sets with a competitive performance over some state-of-the-art techniques.

Qi, Baojun; Wu, Tao; He, Hangen

2012-02-01

182

The design of passively athermalized narrow- and wide-field-of-view infrared objectives for the OBSERVER unmanned air vehicle  

NASA Astrophysics Data System (ADS)

Some years ago QinetiQ introduced a short-range reconnaissance unmanned air vehicle (UAV), known as OBSERVER, which carried a visible three-camera sensor. To increase its versatility, a compatible infrared (IR) thermal imaging (TI) sensor was developed for the vehicle for operation in the 8-12mm waveband with a dual field of view function. The sensor incorporates a specially designed camera board, employing two IR lead scandium tantalate (PST) detectors based on UK un-cooled TI technology. Since no cooling engine is required for the detectors, the sensor module is very lightweight and hence well suited to its UAV application. So as to achieve the minimum possible payload for the vehicle, in addition to the lightweight detectors and electronics board, compact low mass optical solutions were devised for the camera objectives. These functioned at a relative aperture of f/1.0 and were designed to provide stable focus and imaging performance over a comparatively large temperature span (-10°C to + 50°C) to enable all weather operation. In order to achieve an athermalisation scheme devoid of elaborate electro-mechanical drives, thermally passive solutions were developed for the objectives in which the differing thermal characteristics of the components were designed to self-cancel optically. In this paper, the design and performance limitations of the optics are discussed and the procedure employed for establishing a thin lens pre-design for one of the objectives is described.

Simmons, Richard C.; Manning, Paul A.; Chamberlain, Trevor V.

2004-12-01

183

Infrared  

NASA Astrophysics Data System (ADS)

'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the underlying physics. There are now at least six different disciplines that deal with infrared radiation in one form or another, and in one or several different spectral portions of the whole IR range. These are spectroscopy, astronomy, thermal imaging, detector and source development and metrology, as well the field of optical data transmission. Scientists working in these fields range from chemists and astronomers through to physicists and even photographers. This issue presents examples from some of these fields. All the papers—though some of them deal with fundamental or applied research—include interesting elements that make them directly applicable to university-level teaching at the graduate or postgraduate level. Source (e.g. quantum cascade lasers) and detector development (e.g. multispectral sensors), as well as metrology issues and optical data transmission, are omitted since they belong to fundamental research journals. Using a more-or-less arbitrary order according to wavelength range, the issue starts with a paper on the physics of near-infrared photography using consumer product cameras in the spectral range from 800 nm to 1.1 µm [1]. It is followed by a series of three papers dealing with IR imaging in spectral ranges from 3 to 14 µm [2-4]. One of them deals with laboratory courses that may help to characterize the IR camera response [2], the second discusses potential applications for nondestructive testing techniques [3] and the third gives an example of how IR thermal imaging may be used to understand cloud cover of the Earth [4], which is the prerequisite for successful climate modelling. The next two papers cover the vast field of IR spectroscopy [5, 6]. The first of these deals with Fourier transform infrared spectroscopy in the spectral range from 2.5 to 25 µm, studying e.g. ro-vibrational excitations in gases or optical phonon interactions within solids [5]. The second deals mostly with the spectroscopy of liquids such as biofuels and special techniques such as attenuated total reflectance [6]. The two final papers deal with what se

Vollmer, M.

2013-11-01

184

A PAN-CARINA YOUNG STELLAR OBJECT CATALOG: INTERMEDIATE-MASS YOUNG STELLAR OBJECTS IN THE CARINA NEBULA IDENTIFIED VIA MID-INFRARED EXCESS EMISSION  

SciTech Connect

We present a catalog of 1439 young stellar objects (YSOs) spanning the 1.42 deg{sup 2} field surveyed by the Chandra Carina Complex Project (CCCP), which includes the major ionizing clusters and the most active sites of ongoing star formation within the Great Nebula in Carina. Candidate YSOs were identified via infrared (IR) excess emission from dusty circumstellar disks and envelopes, using data from the Spitzer Space Telescope (the Vela-Carina survey) and the Two-Micron All Sky Survey. We model the 1-24 {mu}m IR spectral energy distributions of the YSOs to constrain physical properties. Our Pan-Carina YSO Catalog (PCYC) is dominated by intermediate-mass (2 M{sub sun} < m {approx}< 10 M{sub sun}) objects with disks, including Herbig Ae/Be stars and their less evolved progenitors. The PCYC provides a valuable complementary data set to the CCCP X-ray source catalogs, identifying 1029 YSOs in Carina with no X-ray detection. We also catalog 410 YSOs with X-ray counterparts, including 62 candidate protostars. Candidate protostars with X-ray detections tend to be more evolved than those without. In most cases, X-ray emission apparently originating from intermediate-mass, disk-dominated YSOs is consistent with the presence of low-mass companions, but we also find that X-ray emission correlates with cooler stellar photospheres and higher disk masses. We suggest that intermediate-mass YSOs produce X-rays during their early pre-main-sequence evolution, perhaps driven by magnetic dynamo activity during the convective atmosphere phase, but this emission dies off as the stars approach the main sequence. Extrapolating over the stellar initial mass function scaled to the PCYC population, we predict a total population of >2 x 10{sup 4} YSOs and a present-day star formation rate (SFR) of >0.008 M{sub sun} yr{sup -1}. The global SFR in the Carina Nebula, averaged over the past {approx}5 Myr, has been approximately constant.

Povich, Matthew S.; Getman, Konstantin V.; Townsley, Leisa K.; Broos, Patrick S. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Smith, Nathan [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Majewski, Steven R.; Indebetouw, Remy [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Babler, Brian L.; Meade, Marilyn R.; Whitney, Barbara A. [Department of Astronomy, University of Wisconsin, 475 N. Charter Street, Madison, WI 53706 (United States); Robitaille, Thomas P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Yonekura, Yoshinori [Department of Physical Science, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan); Fukui, Yasuo, E-mail: povich@astro.psu.edu [Department of Astrophysics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

2011-05-01

185

Hemodynamic mechanisms underlying prolonged post-faint hypotension  

Microsoft Academic Search

Objective  During hypotension induced by tilt-table testing, low presyncopal blood pressure (BP) usually recovers within 1 min after\\u000a tilt back. However, in some patients prolonged post faint hypotension (PPFH) is observed. We assessed the hemodynamics underlying\\u000a PPFH in a retrospective study.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Seven patients (2 females, aged 31–72 years) experiencing PPFH were studied. PPFH was defined as a systolic BP below 85 mmHg\\u000a for at

Wouter Wieling; Josien Rozenberg; Ingeborg K. Go-Schön; John M. Karemaker; Berend E. Westerhof; David L. Jardine

186

AKARI Near-Infrared Spectroscopy: Detection of H2O and CO2 Ices toward Young Stellar Objects in the Large Magellanic Cloud  

Microsoft Academic Search

We present the first results of AKARI Infrared Camera near-infrared spectroscopic survey of the Large Magellanic Cloud (LMC). We detected absorption features of the H2O ice 3.05 mum and the CO2 ice 4.27 mum stretching mode toward seven massive young stellar objects (YSOs). These samples are for the first time spectroscopically confirmed to be YSOs. We used a curve-of-growth method

Takashi Shimonishi; Takashi Onaka; Daisuke Kato; Itsuki Sakon; Yoshifusa Ita; Akiko Kawamura; Hidehiro Kaneda

2008-01-01

187

The AGN, Star-forming, and Morphological Properties of Luminous IR-bright/optically-faint Galaxies  

NASA Astrophysics Data System (ADS)

We present the active galactic nucleus (AGN), star-forming, and morphological properties of a sample of 13 MIR-luminous (f 24 >~ 700 ?Jy) IR-bright/optically-faint galaxies (IRBGs, f 24/f R >~ 1000). While these z ~ 2 sources were drawn from deep Chandra fields with >200 ks X-ray coverage, only seven are formally detected in the X-ray and four lack X-ray emission at even the 2? level. Spitzer InfraRed Spectrograph (IRS) spectra, however, confirm that all of the sources are AGN-dominated in the mid-IR, although half have detectable polycyclic aromatic hydrocarbon (PAH) emission responsible for ~25% of their mid-infrared flux density. When combined with other samples, this indicates that at least 30%-40% of luminous IRBGs have star formation rates in the ultraluminous infrared galaxy (ULIRG) range (~100-2000 M sun yr-1). X-ray hardness ratios and MIR to X-ray luminosity ratios indicate that all members of the sample contain heavily X-ray obscured AGNs, 80% of which are candidates to be Compton thick. Furthermore, the mean X-ray luminosity of the sample, log L 2-10 keV (erg s-1) ~44.6, indicates that these IRBGs are Type 2 QSOs, at least from the X-ray perspective. While those sources most heavily obscured in the X-ray are also those most likely to display strong silicate absorption in the mid-IR, silicate absorption does not always accompany X-ray obscuration. Finally, ~70% of the IRBGs are merger candidates, a rate consistent with that of sub-mm galaxies (SMGs), although SMGs appear to be physically larger than IRBGs. These characteristics are consistent with the proposal that these objects represent a later, AGN-dominated, and more relaxed evolutionary stage following soon after the star-formation-dominated one represented by the SMGs.

Donley, J. L.; Rieke, G. H.; Alexander, D. M.; Egami, E.; Pérez-González, P. G.

2010-08-01

188

Faint Detection of Exoplanets in Microlensing Surveys  

NASA Astrophysics Data System (ADS)

We propose a new approach to discovering faint microlensing signals below traditional thresholds, and for estimating the binary-lens mass ratio and the apparent separation from such signals. The events found will be helpful in accurately estimating the true distribution of planetary semimajor axes, which is an important goal of space microlensing surveys.

Brown, Robert A.

2014-06-01

189

Infrared Astronomy  

NSDL National Science Digital Library

NASA's Infrared Processing and Analysis Center (IPAC) provides the Infrared Astronomy Website as one of its outreach programs. Infrared Astronomy, or "the detection and study of the infrared radiation (heat energy) emitted from objects in the Universe," is described and placed in context in the sections Discovery of Infrared, What is Infrared, Infrared Astronomy, Background, and the Infrared Universe. For current information, see the News & Discoveries, Active/ Future Projects, and Activities sections; past and current projects supported by IPAC are featured in the Infrared Gallery. The site targets a broad audience and is geared towards many learning levels.

190

Faint blue stars in the core of NGC 6397  

NASA Astrophysics Data System (ADS)

The inner core of the globular cluster NGC 6397 within approximately 6 arcsecs of the geometrical centre has been investigated with high resolution deep images taken through several medium- and broad-band UV filters with the Faint Object Camera (FOC) on board the Hubble Space Telescope (HST). Approximately 110 stars down to instrumental magnitude m210 approximately equal to 23 were reliably identified in this region and located on a UV-U color magnitude diagram for the first time. The main sequence is well defined down to visual magnitude approximately equal to 6.3, corresponding to a mass of approximately 0.6 solar mass. Four faint blue stars are identified, with UV-U band coarse spectra compatible with black body temperatures in the range 10,000-20,000 K, whose fluxes show considerable variability over a 5 hour time interval. The four objects are all located inside the 90% confidence radius around the position of the possibly multiple low luminosity X-ray source C3 (Cool. 1993), and as such are strong candidates to the optical counterparts. The estimated LX/LV ratio suggests that these objects are cataclysmic variables.

de Marchi, G.; Paresce, F.

1994-01-01

191

Near Infrared Observations Of TNOs With SINFONI  

NASA Astrophysics Data System (ADS)

The trans-Neptunian objects are probably the most primitive objects in the Solar System and their study carries important clues about the history of formation and evolution of our planetary system. From 2001 the Meudon group started an observational campaign at VLT/ESO to observe by spectroscopy these faint and distant objects to investigate their surface composition. Recently, a new instrument has been installed, the Spectrograph for INtegral Field Observations in the Near Infrared, SINFONI. This instrument allows to obtain cubes of data with spectra of medium resolution of TNOs, useful to search for subtle absorption features. Here we present data for four objects: the scattered disk object (26375) 1999 DE9, the plutinos (38628) Huya, and (47932) 2000 GN171, and the centaur (83982) Crantor searching for possible rotational inhomogeneities and/or features on their spectra. A comparison with previous published observations shows that rotational heterogeneities can be present in at least two of the objects.

Alvarez-Candal, Alvaro; Barucci, M. A.; Merlin, F.; Guibert, A.; de Bergh, C.

2007-10-01

192

Faint Satellites of Outer Planets  

NASA Astrophysics Data System (ADS)

In astronomy, as in other matters, the charm 01 novelty is one of the important lactors that govern the choice 01 the observations. How many objects saw suddenly many eyes or kinds of detectors looking at them, before linding again, some months or years later, their sidereal quietness! ... However, it is often after a long time of regular observations that they confide a (small) part 01 their secrets. The laint satellites 01 planets don't transgress this fortunately approximative rule. The deliciency in observations during many consecutive years makes the determination 01 their motion very difficult, and it is olten too late to make up lor lost time. We shall try to i1lustrate this lact in the next lines using the observations of the systems of Saturn, Uranus and Neptune we made in April 1981 on the DanishESO 1.5-m reflector.

Veillet, C.

1982-03-01

193

The nature of faint fuzzies from the kinematics of NGC 1023  

NASA Astrophysics Data System (ADS)

Faint fuzzies are metal-rich apparently-old star clusters with unusually large radii (7-15 pc), found mostly in S0 galaxies, whose source remain obscure. To identify their origins, we compare planetary nebulae and neutral hydrogen with faint fuzzy positions and line-of-sight velocities in NGC 1023. In this way, we rule out scenarios in which these objects are associated with an on-going merger or with a spheroid population in NGC 1023. Their kinematics are indistinguishable from the stellar disk population in this galaxy, and we conclude that faint fuzzies are most likely just remnant open clusters. Their observed association with S0s then simply reflects the difficulty of identifying such objects in later-type disk galaxies.

Chies-Santos, A. L.; Cortesi, A.; Fantin, D. S. M.; Merrifield, M. R.; Bamford, S.; Serra, P.

2013-11-01

194

Home Alone Faint Detection Surveillance System Using Thermal Camera  

Microsoft Academic Search

Fainting is the unwanted event occur amongst the senior citizens, patients or pregnant women. This event can cause physical injuries or even mental problems. In this paper, we proposed a simple faint detection algorithm apply into a thermal imaging camera to monitor the fainting event. In addition, this system is to allow the immediate treatment can be carried out for

Wai Kit Wong; Hong Liang Lim; Chu Kiong Loo

2010-01-01

195

GRAVITY: the adaptive-optics-assisted two-object beam combiner instrument for the VLTI  

NASA Astrophysics Data System (ADS)

We present the adaptive optics assisted, near-infrared VLTI instrument - GRAVITY - for precision narrow-angle astrometry and interferometric phase referenced imaging of faint objects. Precision astrometry and phase-referenced interferometric imaging will realize the most advanced vision of optical/infrared interferometry with the VLT. Our most ambitious science goal is to study motions within a few times the event horizon size of the Galactic Center massive black hole and to test General Relativity in its strong field limit. We define the science reference cases for GRAVITY and derive the top level requirements for GRAVITY. The installation of the instrument at the VLTI is planned for 2012.

Gillessen, S.; Perrin, G.; Brandner, W.; Straubmeier, C.; Eisenhauer, F.; Rabien, S.; Eckart, A.; Lena, P.; Genzel, R.; Paumard, T.; Hippler, S.

2006-07-01

196

A scanning near-field middle-infrared microscope for the study of objects submerged in water  

NASA Astrophysics Data System (ADS)

We had developed a scanning near-field middle-infrared microscope, based on AgClBr probes, which has a subwavelength resolution in air. We adapted this microscope for imaging of samples submerged in water. Toward this goal, we had to develop a theoretical model for the mechanical vibration of the probes in water and use it for the construction of an improved microscope. Using this system, we obtained infrared and topographic images of polymer beads of subwavelength diameters. This microscope will be particularly useful for high resolution spectral imaging of living biological cells in the middle infrared.

Platkov, Max; Tsun, Alexander; Nagli, Lev; Katzir, Abraham

2008-03-01

197

Determination of astrometry and photometry of faint companions in the presence of residual speckle noise  

NASA Astrophysics Data System (ADS)

In this paper we examine approaches to faint companion detection and estimation in multi-spectral images. We will employ the Hotelling observer which is the optimal linear algorithm for signal detection. We have shown how to use this observer to estimate faint object position and brightness in the presence of residual speckle which usually limit astrometric and photometric techniques. These speckles can be reduced by differential imaging techniques such as Angular Differential Imaging and Spectral Differential Imaging. Here we present results based on simulations of adaptive optics corrected images from an ELT which contain quasi-static speckle noise. The simulation includes Angular Differential Imaging to reduce the residual speckle and subsequent multi-wavelenght processing. We examine the feasibility of this approach on simulated ELT observations of faint companions.

Burke, Daniel; Devaney, Nicholas; Gladysz, Szymon

198

OPTICAL/NEAR-INFRARED SELECTION OF RED QUASI-STELLAR OBJECTS: EVIDENCE FOR STEEP EXTINCTION CURVES TOWARD GALACTIC CENTERS?  

SciTech Connect

We present the results of a search for red QSOs using a selection based on optical imaging from the Sloan Digital Sky Survey (SDSS) and near-infrared imaging from UKIDSS. Our main goal with the selection is to search for QSOs reddened by foreground dusty absorber galaxies. For a sample of 58 candidates (including 20 objects fulfilling our selection criteria that already have spectra in the SDSS), 46 (79%) are confirmed to be QSOs. The QSOs are predominantly dust-reddened except for a handful at redshifts z {approx}> 3.5. However, the dust is most likely located in the QSO host galaxies (and for two, the reddening is primarily caused by Galactic dust) rather than in the intervening absorbers. More than half of the QSOs show evidence of associated absorption (BAL absorption). Four (7%) of the candidates turned out to be late-type stars, and another four (7%) are compact galaxies. We could not identify the remaining four objects. In terms of their optical spectra, these QSOs are similar to the QSOs selected in the FIRST-2MASS Red Quasar Survey except they are on average fainter, more distant, and only two are detected in the FIRST survey. As per the usual procedure, we estimate the amount of extinction using the SDSS QSO template reddened by Small-Magellanic-Cloud-(SMC) like dust. It is possible to get a good match to the observed (rest-frame ultraviolet) spectra, but it is not possible to match the observed near-IR photometry from UKIDSS for nearly all the reddened QSOs. The most likely reasons are that the SDSS QSO template is too red at optical wavelengths due to contaminating host galaxy light and because the assumed SMC extinction curve is too shallow. Three of the compact galaxies display old stellar populations with ages of several Gyr and masses of about 10{sup 10} M{sub Sun} (based on spectral energy distribution modeling). The inferred stellar densities in these galaxies exceed 10{sup 10} M{sub Sun} kpc{sup -2}, which is among the highest measured for early-type galaxies. Our survey has demonstrated that selection of QSOs based on near-IR photometry is an efficient way to select QSOs, including reddened QSOs, with only small contamination from late-type stars and compact galaxies. This will be useful with ongoing and future wide-field near-IR surveys such as the VISTA and EUCLID surveys.

Fynbo, J. P. U.; Krogager, J.-K.; Vestergaard, M.; Geier, S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Venemans, B. [Max-Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Noterdaeme, P. [CNRS-UPMC, UMR7095, Institut d'Astrophysique de Paris, 98bis Bd. Arago, F-75014 Paris (France); Moller, P. [European Southern Observatory, Karl-Schwarzschildstrasse 2, D-85748 Garching bei Muenchen (Germany); Ledoux, C. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile)

2013-01-15

199

Infrared Gallery  

NSDL National Science Digital Library

How would your world look if you saw heat instead of light? In this interactive resource produced for Teachers' Domain, see what familiar objects look like through an infrared camera and watch infrared videos of geysers, mudpots, and hot springs.

Foundation, Wgbh E.

2005-10-21

200

MOVING OBJECTS IN THE HUBBLE ULTRA DEEP FIELD  

SciTech Connect

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.

Kilic, Mukremin; Gianninas, Alexandros [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States); Von Hippel, Ted, E-mail: kilic@ou.edu, E-mail: alexg@nhn.ou.edu, E-mail: ted.vonhippel@erau.edu [Embry-Riddle Aeronautical University, 600 S. Clyde Morris Blvd., Daytona Beach, FL 32114 (United States)

2013-09-01

201

Moving Objects in the Hubble Ultra Deep Field  

NASA Astrophysics Data System (ADS)

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? 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 × 10-3 pc-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. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Kilic, Mukremin; Gianninas, Alexandros; von Hippel, Ted

2013-09-01

202

Verifying FGS FSW on Faint Targets  

NASA Astrophysics Data System (ADS)

New FGS flight software has been implemented to facilitate the reliable acquisition and tracking of faint stars in POS mode and for the reliable positioning of the scan path in Trans mode. The target in this proposal has been observed as visit 35 in proposal 9169, without the new FGS FSW. In that instance IFOV wandered by about 0.6" before the start of the Transfer mode scans, causing the scan path to be situated such that the y-axis interferogram was not sampled. This target, a V=15.8 white dwarf, is to be re-observed in this proposal to verify the effectiveness of the new FSW.

Nelan, Edmund

2001-07-01

203

The formation of Jupiter's faint rings  

PubMed

Observations by the Galileo spacecraft and the Keck telescope showed that Jupiter's outermost (gossamer) ring is actually two rings circumscribed by the orbits of the small satellites Amalthea and Thebe. The gossamer rings' unique morphology-especially the rectangular end profiles at the satellite's orbit and the enhanced intensities along the top and bottom edges of the rings-can be explained by collisional ejecta lost from the inclined satellites. The ejecta evolves inward under Poynting-Robertson drag. This mechanism may also explain the origin of Jupiter's main ring and suggests that faint rings may accompany all small inner satellites of the other jovian planets. PMID:10325220

Burns; Showalter; Hamilton; Nicholson; de Pater I; Ockert-Bell; Thomas

1999-05-14

204

Herschel-ATLAS: the far-infrared properties and star formation rates of broad absorption line quasi-stellar objects  

NASA Astrophysics Data System (ADS)

We have used data from the Herschel Astrophysical Terahertz Large-Area Survey (H-ATLAS) at 250, 350 and 500 ?m to determine the far-infrared (FIR) properties of 50 broad absorption line quasars (BAL QSOs). Our sample contains 49 high-ionization BAL QSOs (HiBALs) and one low-ionization BAL QSO (LoBAL) which are compared against a sample of 329 non-BAL QSOs. These samples are matched over the redshift range 1.5 ? z < 2.3 and in absolute i-band magnitude over the range -28 ? Mi ? -24. Of these, three BAL QSOs (HiBALs) and 27 non-BAL QSOs are detected at the >5 ? level. We calculate star formation rates (SFRs) for our individually detected HiBAL QSOs and the non-detected LoBAL QSO as well as average SFRs for the BAL and non-BAL QSO samples based on stacking the Herschel data. We find no difference between the HiBAL and non-BAL QSO samples in the FIR, even when separated based on differing BAL QSO classifications. Using Mrk 231 as a template, the weighted mean SFR is estimated to be ?240 ± 21 M? yr-1 for the full sample, although this figure should be treated as an upper limit if active galactic nucleus (AGN)-heated dust makes a contribution to the FIR emission. Despite tentative claims in the literature, we do not find a dependence of C IV equivalent width on FIR emission, suggesting that the strength of any outflow in these objects is not linked to their FIR output. These results strongly suggest that BAL QSOs (more specifically HiBALs) can be accommodated within a simple AGN unified scheme in which our line of sight to the nucleus intersects outflowing material. Models in which HiBALs are caught towards the end of a period of enhanced spheroid and black hole growth, during which a wind terminates the star formation activity, are not supported by the observed FIR properties. The Herschel-ATLAS is a project with Herschel, which is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. The H-ATLAS website is http://www/h-atlas.org/.

Cao Orjales, J. M.; Stevens, J. A.; Jarvis, M. J.; Smith, D. J. B.; Hardcastle, M. J.; Auld, R.; Baes, M.; Cava, A.; Clements, D. L.; Cooray, A.; Coppin, K.; Dariush, A.; De Zotti, G.; Dunne, L.; Dye, S.; Eales, S.; Hopwood, R.; Hoyos, C.; Ibar, E.; Ivison, R. J.; Maddox, S.; Page, M. J.; Valiante, E.

2012-12-01

205

Luminosity function of faint galaxies with ultraviolet continuum  

NASA Astrophysics Data System (ADS)

Data on 86 galaxies of apparent B magnitude 13.8-18.5 with UV continuum emission from the second Biurakan survey (Markarian and Stepanian, 1983 and 1984) are compiled in a table and used to determine the luminosity function. The distribution of apparent magnitudes is analyzed, correcting for absorption in the Galaxy; the method of Terebizh (1980) is used to estimate the luminosity function; and the results are presented in graphs and tables. The average spatial density of faint UV-continum galaxies is found to be 1.8/sq deg, about 8 percent of the density of field galaxies of the same luminosity in the luminosity range -16.5 to -21.5 mag and about 0.1/cu Mpc per unit of magnitude in the interval -12.5 to -15.5 mag, with about 10-13 percent Seyfert galaxies (when blue stellar objects and QSOs are not taken into account).

Stepanian, D. A.

1984-05-01

206

Optical/Near-infrared Selection of Red Quasi-stellar Objects: Evidence for Steep Extinction Curves toward Galactic Centers?  

NASA Astrophysics Data System (ADS)

We present the results of a search for red QSOs using a selection based on optical imaging from the Sloan Digital Sky Survey (SDSS) and near-infrared imaging from UKIDSS. Our main goal with the selection is to search for QSOs reddened by foreground dusty absorber galaxies. For a sample of 58 candidates (including 20 objects fulfilling our selection criteria that already have spectra in the SDSS), 46 (79%) are confirmed to be QSOs. The QSOs are predominantly dust-reddened except for a handful at redshifts z >~ 3.5. However, the dust is most likely located in the QSO host galaxies (and for two, the reddening is primarily caused by Galactic dust) rather than in the intervening absorbers. More than half of the QSOs show evidence of associated absorption (BAL absorption). Four (7%) of the candidates turned out to be late-type stars, and another four (7%) are compact galaxies. We could not identify the remaining four objects. In terms of their optical spectra, these QSOs are similar to the QSOs selected in the FIRST-2MASS Red Quasar Survey except they are on average fainter, more distant, and only two are detected in the FIRST survey. As per the usual procedure, we estimate the amount of extinction using the SDSS QSO template reddened by Small-Magellanic-Cloud-(SMC) like dust. It is possible to get a good match to the observed (rest-frame ultraviolet) spectra, but it is not possible to match the observed near-IR photometry from UKIDSS for nearly all the reddened QSOs. The most likely reasons are that the SDSS QSO template is too red at optical wavelengths due to contaminating host galaxy light and because the assumed SMC extinction curve is too shallow. Three of the compact galaxies display old stellar populations with ages of several Gyr and masses of about 1010 M ? (based on spectral energy distribution modeling). The inferred stellar densities in these galaxies exceed 1010 M ? kpc-2, which is among the highest measured for early-type galaxies. Our survey has demonstrated that selection of QSOs based on near-IR photometry is an efficient way to select QSOs, including reddened QSOs, with only small contamination from late-type stars and compact galaxies. This will be useful with ongoing and future wide-field near-IR surveys such as the VISTA and EUCLID surveys. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under program 088.A-0098, and on observations made with the Nordic Optical Telescope, jointly operated on the island of La Palma by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.

Fynbo, J. P. U.; Krogager, J.-K.; Venemans, B.; Noterdaeme, P.; Vestergaard, M.; Møller, P.; Ledoux, C.; Geier, S.

2013-01-01

207

A spectroscopic search for faint secondaries in cataclysmic variables  

NASA Astrophysics Data System (ADS)

The secondary in cataclysmic variables (CVs) is usually detected by cross-correlation of the CV spectrum with that of a K or M dwarf template, to produce a radial velocity curve. Although this method has demonstrated its power, it has its limits in the case of noisy spectra, such as are found when the secondary is faint. A method of coadding spectra, called skew mapping, has been proposed in the past. Gradually, examples of its application are being published; none the less, so far no journal article has described the technique in detail. To answer this need, this paper explores in detail the capabilities of skew mapping when determining the amplitude of the radial velocity for faint secondaries. It demonstrates the power of the method over techniques that are more conventional, when the signal-to-noise ratio is poor. The paper suggests an approach to assessing the quality of results. This leads in the case of the investigated objects to a first tier of results, where we find K2= 127 +/- 23 km s-1 for SY Cnc, K2= 144 +/- 18 km s-1 for RW Sex and K2= 262 +/- 14 km s-1 for UX UMa. These we believe to be the first direct determinations of K2 for these objects. Furthermore, we also obtain K2= 263 +/- 30 km s-1 for RW Tri, close to a skew mapping result obtained elsewhere. In the first three cases, we use these results to derive the mass of the white dwarf companion. A second tier of results includes UU Aqr, EX Hya and LX Ser, for which we propose more tentative values of K2. Clear failures of the method are also discussed (EF Eri, VV Pup and SW Sex).

Vande Putte, D.; Smith, Robert Connon; Hawkins, N. A.; Martin, J. S.

2003-06-01

208

Laser-and-holographic complex for technological and certification control of optical elements and objectives in infrared spectral region of 3-12 ?m  

NASA Astrophysics Data System (ADS)

We have considered here a functional scheme, peculiarities of operation, advantages and prospectives of using of a laser-and- holographic complex created in Federal State Unitary Enterprise "Scientific-and-Production Association "State Institute of Applied Optics' (FGUP "NPO "GIPO"). The complex is intended for technological and certification control of separate optical elements as well as objectives in infrared spectral region of 3-12 ?m.

Duchitskiy, Alexander S.; Lukin, Anatoliy V.; Mavrin, Sergey V.; Melnikov, Andrey N.

2007-05-01

209

GRAVITY: The AO-Assisted, Two-Object Beam-Combiner Instrument for the VLTI  

NASA Astrophysics Data System (ADS)

We present the proposal for the infrared adaptive optics (AO) assisted, two-object, high-throughput, multiple-beam-combiner GRAVITY for the VLTI. This instrument will be optimized for phase-referenced interferometric imaging and narrow-angle astrometry of faint, red objects. Following the scientific drivers, we analyze the VLTI infrastructure, and subsequently derive the requirements and concept for the optimum instrument. The analysis can be summarized with the need for highest sensitivity, phase referenced imaging and astrometry of two objects in the VLTI beam, and infrared wavefront-sensing. Consequently our proposed instrument allows the observations of faint, red objects with its internal infrared wavefront sensor, pushes the optical throughput by restricting observations to K-band at low and medium spectral resolution, and is fully enclosed in a cryostat for optimum background suppression and stability. Our instrument will thus increase the sensitivity of the VLTI significantly beyond the present capabilities. With its two fibers per telescope beam, GRAVITY will not only allow the simultaneous observations of two objects, but will also push the astrometric accuracy for UTs to 10 ?as, and provide simultaneous astrometry for up to six baselines.

Eisenhauer, F.; Perrin, G.; Rabien, S.; Eckart, A.; Léna, P.; Genzel, R.; Abuter, R.; Paumard, T.; Brandner, W.

210

GRAVITY: The AO assisted, two object beam combiner instrument for the VLTI.  

NASA Astrophysics Data System (ADS)

We present the proposal for the infrared adaptive optics (AO) assisted, two-object, high-throughput, multiple-beam-combiner GRAVITY for the VLTI. This instrument will be optimized for phase-referenced interferometric imaging and narrow-angle astrometry of faint, red objects. Following the scientific drivers, we analyze the VLTI infrastructure, and subsequently derive the requirements and concept for the optimum instrument. The analysis can be summarized with the need for highest sensitivity, phase referenced imaging and astrometry of two objects in the VLTI beam, and infrared wavefront-sensing. Consequently our proposed instrument allows the observations of faint, red objects with its internal infrared wavefront sensor, pushes the optical throughput by restricting observations to K-band at low and medium spectral resolution, and is fully enclosed in a cryostat for optimum background suppression and stability. Our instrument will thus increase the sensitivity of the VLTI significantly beyond the present capabilities. With its two fibers per telescope beam, GRAVITY will not only allow the simultaneous observations of two objects, but will also push the astrometric accuracy for UTs to 10 micro-arcsec, and provide simultaneous astrometry for up to six baselines.

Eisenhauer, F.; Perrin, G.; Rabien, S.; Eckart, A.; Lena, P.; Genzel, R.; Abuter, R.; Paumard, T.

2005-08-01

211

An X-Ray and Infrared Survey of the Lynds 1228 Cloud Core  

NASA Astrophysics Data System (ADS)

The nearby Lynds 1228 (L1228) dark cloud at a distance of ~200 pc is known to harbor several young stars including the driving sources of the giant HH 199 and HH 200 Herbig-Haro (HH) outflows. L1228 has previously been studied at optical, infrared, and radio wavelengths but not in X-rays. We present results of a sensitive 37 ks Chandra ACIS-I X-ray observation of the L1228 core region. Chandra detected 60 X-ray sources, most of which are faint (<40 counts) and non-variable. Infrared counterparts were identified for 53 of the 60 X-ray sources using archival data from the Two Micron All-Sky Survey, the Spitzer Space Telescope, and the Wide-field Infrared Survey Explorer. Object classes were assigned using mid-IR colors for those objects with complete photometry, most of which were found to have colors consistent with extragalactic background sources. Seven young stellar object candidates were identified including the class I protostar HH 200-IRS which was detected as a faint hard X-ray source. No X-ray emission was detected from the luminous protostar HH 199-IRS. We summarize the X-ray and infrared properties of the detected sources and provide IR spectral energy distribution modeling of high-interest objects including the protostars driving the HH outflows.

Skinner, Stephen L.; Rebull, Luisa; Güdel, Manuel

2014-04-01

212

THE AGN, STAR-FORMING, AND MORPHOLOGICAL PROPERTIES OF LUMINOUS IR-BRIGHT/OPTICALLY-FAINT GALAXIES  

SciTech Connect

We present the active galactic nucleus (AGN), star-forming, and morphological properties of a sample of 13 MIR-luminous (f {sub 24} {approx}> 700 {mu}Jy) IR-bright/optically-faint galaxies (IRBGs, f{sub 24}/f {sub R} {approx}> 1000). While these z {approx} 2 sources were drawn from deep Chandra fields with >200 ks X-ray coverage, only seven are formally detected in the X-ray and four lack X-ray emission at even the 2{sigma} level. Spitzer InfraRed Spectrograph (IRS) spectra, however, confirm that all of the sources are AGN-dominated in the mid-IR, although half have detectable polycyclic aromatic hydrocarbon (PAH) emission responsible for {approx}25% of their mid-infrared flux density. When combined with other samples, this indicates that at least 30%-40% of luminous IRBGs have star formation rates in the ultraluminous infrared galaxy (ULIRG) range ({approx}100-2000 M{sub sun} yr{sup -1}). X-ray hardness ratios and MIR to X-ray luminosity ratios indicate that all members of the sample contain heavily X-ray obscured AGNs, 80% of which are candidates to be Compton thick. Furthermore, the mean X-ray luminosity of the sample, log L{sub 2-10keV}(erg s{sup -1}) {approx}44.6, indicates that these IRBGs are Type 2 QSOs, at least from the X-ray perspective. While those sources most heavily obscured in the X-ray are also those most likely to display strong silicate absorption in the mid-IR, silicate absorption does not always accompany X-ray obscuration. Finally, {approx}70% of the IRBGs are merger candidates, a rate consistent with that of sub-mm galaxies (SMGs), although SMGs appear to be physically larger than IRBGs. These characteristics are consistent with the proposal that these objects represent a later, AGN-dominated, and more relaxed evolutionary stage following soon after the star-formation-dominated one represented by the SMGs.

Donley, J. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Rieke, G. H.; Egami, E.; Perez-Gonzalez, P. G. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Alexander, D. M., E-mail: donley@stsci.ed [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)

2010-08-20

213

Observing Faint Companions Close to Bright Stars  

NASA Astrophysics Data System (ADS)

Progress in a number of technical areas is enabling imaging and interferometric observations at both smaller angular separations from bright stars and at deeper relative contrast levels. Here we discuss recent progress in several ongoing projects at the Jet Propulsion Laboratory. First, extreme adaptive optics wavefront correction has recently enabled the use of very short (i.e., blue) wavelengths to resolve close binaries. Second, phase-based coronagraphy has recently allowed observations of faint companions to within nearly one diffraction beam width of bright stars. Finally, rotating interferometers that can observe inside the diffraction beam of single aperture telescopes are being developed to detect close-in companions and bright exozodiacal dust. This paper presents a very brief summary of the techniques involved, along with some illustrative results.

Serabyn, Eugene

2012-04-01

214

The design of passively athermalized narrow- and wide-field-of-view infrared objectives for the OBSERVER unmanned air vehicle  

Microsoft Academic Search

Some years ago QinetiQ introduced a short-range reconnaissance unmanned air vehicle (UAV), known as OBSERVER, which carried a visible three-camera sensor. To increase its versatility, a compatible infrared (IR) thermal imaging (TI) sensor was developed for the vehicle for operation in the 8-12mm waveband with a dual field of view function. The sensor incorporates a specially designed camera board, employing

Richard C. Simmons; Paul A. Manning; Trevor V. Chamberlain

2004-01-01

215

MEASURING SIZES OF ULTRA-FAINT DWARF GALAXIES  

SciTech Connect

The discovery of ultra-faint dwarf (UFD) galaxies in the halo of the Milky Way extends the faint end of the galaxy luminosity function to a few hundred solar luminosities. This extremely low luminosity regime poses a significant challenge for the photometric characterization of these systems. We present a suite of simulations aimed at understanding how different observational choices related to the properties of a low-luminosity system impact our ability to determine its true structural parameters such as half-light radius and central surface brightness. We focus on estimating half-light radii (on which mass estimates depend linearly) and find that these numbers can have up to 100% uncertainties when relatively shallow photometric surveys, such as the Sloan Digital Sky Survey, are used. Our simulations suggest that to recover structural parameters within 10% or better of their true values: (1) the ratio of the field of view to the half-light radius of the satellite must be greater than three, (2) the total number of stars, including background objects should be larger than 1000, and (3) the central to background stellar density ratio must be higher than 20. If one or more of these criteria are not met, the accuracy of the resulting structural parameters can be significantly compromised. In the context of future surveys such as Large Synoptic Survey Telescope, the latter condition will be closely tied to our ability to remove unresolved background galaxies. Assessing the reliability of measured structural parameters will become increasingly critical as the next generation of deep wide-field surveys detects UFDs beyond the reach of current spectroscopic limits.

Munoz, Ricardo R. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Padmanabhan, Nikhil; Geha, Marla, E-mail: rmunoz@das.uchile.cl [Department of Astronomy, Yale University, New Haven, CT 06520 (United States)

2012-02-01

216

Optical Color Selection of Faint AGN in the COSMOS Field  

NASA Astrophysics Data System (ADS)

We outline a strategy to select faint (iAB < 25.5) AGN candidates for spectroscopic targeting in the COSMOS field (Scoville et al. 2007, ApJS, in press). Similar in design to the SDSS QSO selection algorithm outlined by Richards et al. (2002), this selection picks candidates by their nonstellar colors in ubvriz broadband photometry from the Subaru and CFH Telescopes. Although the COSMOS field has been used extensively to survey the galaxy population, QSO optical color selection has not been applied to this faint a level. Since the catalog is complete to magnitude iAB < 25.9, we are testing AGN optical color selection at the Seyfert/QSO boundary all the way out to z 3. While stars are easily identified as the dominant contaminant for bright QSO candidate selection at z < 2, we anticipate a high contamination rate from compact red galaxies, which will lower selection efficiency and make the algorithm more complex. To create our candidate pool, we quantify the behavior of the stellar locus in 4D multicolor space. Objects that stray from the locus significantly are tagged as stellar outliers and potential QSO candidates. With a set of 350 known QSOs (X-ray selected, radio selected, and optically selected from SDSS) and type 1 quasar templates designed by Budavari et al. (2001), we have a “training” data set with which to measure efficiency and completeness as a function of redshift. After initial classification in multicolor space, supplemental morphological selection will be applied to stellar outliers using the Gini coefficient, cross-checked against resolved AGN in the training data set, and a final candidate pool will be determined. Candidates will be observed spectroscopically with the IMACS-spectrograph on the Magellan (Baade) Telescope in Chile. This work was partially supported by NSF's REU program at the Institute for Astronomy, University of Hawaii.

Casey, Caitlin M.; Impey, C. D.

2006-12-01

217

Physical and Chemical Properties of Protocluster Clumps and Massive Young Stellar Objects Associated to Infrared Dark Clouds  

NASA Astrophysics Data System (ADS)

The study of high-mass stars is important not only because of the effects they produce in their environment through outflows, expanding HII regions, stellar winds, and eventually supernova shock waves, but also because they play a crucial role in estimating star formation rates in other galaxies. Although we have an accepted evolutionary scenario that explains (isolated) low-mass star formation, the processes that produce massive stars (M_star > 8 M_sol) and star clusters, especially their earliest stages, are not well understood. The newly discovered class of interstellar clouds now termed infrared dark clouds (IRDCs) represent excellent laboratories to study the earliest stages of high-mass star formation given that some of the clumps within them are known to have high masses (~100's M_sol), high densities (n > 10^5 cm^-3), and low temperatures (10-20K) as expected for the birthplaces of high-mass stars. Some questions remain unanswered: Do IRDCs harbor the very early stages of high-mass star formation, i.e., the pre-protocluster phase? If so, how do they compare with low-mass star formation sites? Is there chemical differentiation in IRDC clumps? What is the mass distribution of IRDCs? In this dissertation and for the first time, a catalog of 12529 IRDC candidates at 24 um has been created using archival data from the MIPSGAL/Spitzer survey, as a first step in searching for the massive pre-protocluster clumps. From this catalog, a sample of ~60 clumps has been selected in order to perform single-pointing observations with the IRAM 30m, Effelsberg 100m, and APEX 12m telescopes. One IRDC clump seems to be a promising candidate for being in the pre-protocluster phase. In addition, molecular line mapping observations have been performed on three clumps within IRDCs and a detailed chemical study of 10 molecular lines has been carried out. A larger difference in column densities and abundances has been found between these clumps and high-m! ass protostellar objects than between these clumps and low-mass pre-stellar cores and protostellar objects. A non-LTE Monte Carlo code was used to model the N_2H^+ (1-0) and (3-2) lines in order to constrain the physical properties of two clumps. Six IRDC complexes have been mapped in the 870 um dust continuum emission with the LABOCA instrument on the APEX 12m telescope. Line observations have been carried out in order to obtain temperature and kinematic distances of selected clumps. Physical properties such as masses, effective radii, and column densities have been obtained. The mass spectrum of these clumps has been fitted with a power-law whose best-fitting index is alpha =-1.60. This value is consistent with the CO clump mass function reported in the literature. A relation between the dust emission at 870 um and the degree of extinction (contrast) at 24 um has been obtained by combining dust emission observations and extinction studies. A study with the Plateau de Bure Interferometer of a core in an archetypal filamentary IRDC at few arcsecond resolution has been carried out to determine its physical and chemical structure. Extended 4.5 um emission, "wings" in the CH_3OH 2_k -> 1_k spectra, and a CH_3OH abundance enhancement provide evidence of an outflow in the East-West direction. In addition, a gradient of ~4 km/s in the same direction has been found, which is interpreted as being produced by an outflow(s)-cloud interaction. Finally, Very Large Array interferometric observations of the 7_0-6_1 A^+ (class I) methanol maser transition at 44 GHz toward three high-mass star-forming regions have been carried out in order to provide accurate maser positions and parameters. For all three sources, the masers were well-separated from the HII region, with projected distances ranging from 0.1 to 0.3 pc.

Gomez Gonzalez, Laura

2012-01-01

218

First Results from the ISO-IRAS Faint Galaxy Survey  

Microsoft Academic Search

We present the first results from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12 mu m ISOCAM and 90 mu m ISOPHOT observations. As of 1997 October, over 500

Deborah A. Levine; Carol J. Lonsdale; Robert L. Hurt; Harding E. Smith; George Helou; Charles Beichman; Catherine Cesarsky; David Elbaz; Ulrich Klaas; Rene Laureijs; Detrich Lemke; Steven Lord; Richard McMahon; Mehrdad Moshir; Gerry Neugebauer; B. T. Soifer; Dave van Buren; Ann Wehrle; Ray Wolstencroft

1998-01-01

219

Faints, fits, and fatalities from emotion in Shakespeare's characters: survey of the canon  

PubMed Central

Objectives To determine how often Shakespeare's characters faint, fit, or die from extreme emotion; to assess Shakespeare's uniqueness in this regard; and to examine the plausibility of these dramatised events. Design Line by line search through modern editions of these late 16th and early 17th century works for accounts of characters fainting, fitting, or dying while under strong emotion and for no other apparent reason. Data sources All 39 canonical plays by Shakespeare and his three long narrative poems; 18 similar works by seven of Shakespeare's best known contemporaries. Results 10 deaths from strong emotion are recorded by Shakespeare (three occur on stage); all are due to grief, typically at the loss of a loved one. All but two of the deaths are in the playwright's late works. Some deaths are sudden. Another 29 emotion induced deaths are mentioned as possible, but the likelihood of some can be challenged. Transient loss of consciousness is staged or reported in 18 cases (sounding like epilepsy in two) and near fainting in a further 13. Extreme joy is sometimes depicted as a factor in these events. Emotional death and fainting also occur occasionally in works by Shakespeare's contemporaries. Conclusions These dramatic phenomena are part of the early modern belief system but are also plausible by modern understanding of physiology and disease. They teach us not to underestimate the power of the emotions to disturb bodily functions.

2006-01-01

220

Chemical evolution of classical and ultra-faint dwarf spheroidal galaxies  

NASA Astrophysics Data System (ADS)

We present updated chemical evolution models of two dwarf spheroidal galaxies (Sculptor and Carina) and the first detailed chemical evolution models of two ultra-faint dwarfs (Hercules and Boötes I). Our results suggest that the dwarf spheroidals evolve with a low efficiency of star formation, confirming previous results, and the ultra-faint dwarfs with an even lower one. Under these assumptions, we can reproduce the stellar metallicity distribution function, the [?/Fe] versus [Fe/H] abundance patterns and the total stellar and gas masses observed at the present time in these objects. In particular, for the ultra-faint dwarfs we assume a strong initial burst of star formation, with the mass of the system being already in place at early times. On the other hand, for the classical dwarf spheroidals the agreement with the data is found by assuming the star formation histories suggested by the colour-magnitude diagrams and a longer time-scale of formation via gas infall. We find that all these galaxies should experience galactic winds, starting in all cases before 1 Gyr from the beginning of their evolution. From comparison with Galaxy data, we conclude that it is unlikely that the ultra-faint dwarfs have been the building blocks of the whole Galactic halo, although more data are necessary before drawing firm conclusions.

Vincenzo, F.; Matteucci, F.; Vattakunnel, S.; Lanfranchi, G. A.

2014-07-01

221

The wide-field Fourier spectroscopic-imaging of the radiation heat from the object itself in the middle infrared region for the health monitoring  

NASA Astrophysics Data System (ADS)

We are aiming at the realization of the wide-field spectroscopic-imaging-sensor that is available for the health monitoring or the plant factory. Conventionally, the body temperature is measured by the thermography as a total intensity of the middle infrared radiation. We are trying to analyze the spectroscopic characteristics of the radiation heat from the human body in detail to measure the blood glucose or the moisture-retaining properties of the human skin. The proposed imaging-type 2-dimensional Fourier spectroscopy can measure the radiation heat from the object itself with the wide field of view and the wide wavelength-band. In this proposed method, we install the phase-shifter on the optical Fourier-transform-plane of the imaging optics to give the arbitrary phase-shift to the half flux of the object beams. Thus, the interferogram can be formed on the imaging plane in each bright point by the phase-shift interference-phenomena between the object beams that are emitted from the each corresponding bright point on the objective surface. In this report, we mention the feasibility results of the wide-field spectroscopic-imaging using the black body for the basic optical evaluation and the house plants for measuring the glucose distribution with the infrared camera(wavelength: 8?m-14?m).

Qi, Wei; Takuma, Takashi; Inui, Asuka; Tsutsumi, Ryosuke; Yuzuriha, Takehiko; Kagiyama, Hiroyasu; Kojima, Daisuke; Nishiyama, Akira; Ishimaru, Ichirou

2012-02-01

222

The Angular Clustering of Faint Galaxies in Quasar Fields  

NASA Astrophysics Data System (ADS)

We present a preliminary measurement of the angular clustering of faint galaxies that were detected in known quasar fields. The data were acquired with the Low Resolution Imaging Spectrograph on the 10-m Keck-I telescope and the apparent magnitudes of the detected objects have been corrected for extinction. We characterize the clustering of the galaxies by the two-point correlation function, omega (theta ), and use the minimum variance estimator proposed by Landy & Szalay to compute the correlation functions for the objects detected in each of the independent fields. The data which have been analyzed so far have yielded measurements of omega (theta ) for galaxies with limiting magnitudes of R = 24.5 (17 independent fields) and R = 25.0 (11 independent fields). The mean correlation functions obtained from these fields show the galaxies to be strongly clustered (though not at a level higher than that of objects of similar magnitude detected in random blank fields) and the correlation function is well-characterized by a power law of the from A_omega theta (-delta ) . The best-fit value of the power law index, delta , is of order 1, which is somewhat steeper than the fiducial expected value of delta = 0.8. In the near future we will add additional quasar fields to our determination of omega (theta ) and will also investigate both higher-order correlation functions of the galaxies with themselves as well as the possible clustering of the galaxies with the quasars.

Brainerd, T. G.; Law, C. J.; Brauher, J.; Djorgovski, S. G.; Banas, K.

1999-05-01

223

DISCOVERY AND CHARACTERIZATION OF A FAINT STELLAR COMPANION TO THE A3V STAR zeta VIRGINIS  

SciTech Connect

Through the combination of high-order adaptive optics and coronagraphy, we report the discovery of a faint stellar companion to the A3V star zeta Virginis. This companion is {approx}7 mag fainter than its host star in the H band, and infrared imaging spanning 4.75 years over five epochs indicates this companion has common proper motion with its host star. Using evolutionary models, we estimate its mass to be 0.168{sup +0.012}{sub -0.016} M{sub sun}, giving a mass ratio for this system q = 0.082{sup +0.007}{sub -0.008}. Assuming the two objects are coeval, this mass suggests an M4V-M7V spectral type for the companion, which is confirmed through {integral} field spectroscopic measurements. We see clear evidence for orbital motion from this companion and are able to constrain the semimajor axis to be {approx}>24.9 AU, the period {approx}>124 yr, and eccentricity {approx}>0.16. Multiplicity studies of higher mass stars are relatively rare, and binary companions such as this one at the extreme low end of the mass ratio distribution are useful additions to surveys incomplete at such a low mass ratio. Moreover, the frequency of binary companions can help to discriminate between binary formation scenarios that predict an abundance of low-mass companions forming from the early fragmentation of a massive circumstellar disk. A system such as this may provide insight into the anomalous X-ray emission from A stars, hypothesized to be from unseen late-type stellar companions. Indeed, we calculate that the presence of this M-dwarf companion easily accounts for the X-ray emission from this star detected by ROSAT.

Hinkley, Sasha; Hillenbrand, Lynne [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Oppenheimer, Ben R.; Brenner, Douglas; Zimmerman, Neil; Sivaramakrishnan, Anand [Astrophysics Department, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Roberts, Lewis C.; Roberts, Jennifer E.; Burruss, Rick; Shao, Michael; Vasisht, Gautam [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Parry, Ian R.; King, David L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Soummer, Remi [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Simon, Michal [Stony Brook University, NY (United States); Perrin, Marshall D. [UCLA Department of Astronomy, CA (United States); Lloyd, James P. [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Bouchez, Antonin; Dekany, Richard [Caltech Optical Observatories, California Institute of Technology, Pasadena, CA 91125 (United States); Beichman, Charles [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States)

2010-03-20

224

A new very faint X-ray transient in the Galactic center  

NASA Astrophysics Data System (ADS)

A new X-ray transient, XMMU J174505.3-291445, has been detected within the 2012 XMM-Newton scan of the Galactic center. The short 4.7 ks flare, the highly absorbed X-ray spectrum and the relatively low luminosity of the event suggest the association of the source with either the class of very faint X-ray transients or that of supergiant fast X-ray transients. Further analysis, together with the identification of the possible infrared counterpart will help to unveil the true nature of XMMU J174505.3-291445.

Soldi, Simona; Clavel, Maïca; Goldwurm, Andrea; Ponti, Gabriele; Terrier, Régis; Trap, Guillaume; Greiner, Jochen; Prinz, Tobias; Rau, Arne; Servillat, Mathieu

2014-05-01

225

Is the faint young Sun paradox solved?  

NASA Astrophysics Data System (ADS)

How did the early Earth remain warm despite weak solar luminosity? The faint young Sun paradox has stubbornly resisted a self-consistent solution since it was first introduced by Sagan and Mullen [1] over four decades ago. However, recent revisions to expected paleo-ocean temperatures [2, 3] along with new results from three-dimensional climate models [4] may allow this long standing problem to be finally put to rest. Here we use a modified version of the Community Atmosphere Model version 3 from the National Center for Atmospheric Research to study early climate. We find that resolving the faint young Sun paradox becomes less problematic when viewing a full representation of the climate system. For the late Archean climate (80% solar constant), relatively modest amounts of CO2 (?0.02 bar) and CH4 (0.001 bar) yield surface temperatures equal to the present day with no other alterations to climate. Cooler climates with large ice caps but with temperate tropical regions can be supported with considerably smaller greenhouse gas burdens. The incorporation of systematic climate system elements expected for the Archean such as fewer cloud condensation nuclei (CCN) [5], reduced land albedos [5], and an increased atmospheric inventory of N2 [6], can provide a combined 10 to 20 K of additional surface warming given reasonable assumptions. With the inclusion of 0.001 bar of CH4, 2 PAL of N2, reduced land albedos, and reduced CCN, present day mean surface temperatures can be maintained for the earliest Archean (75% solar constant) with only ~0.01 bar of CO2. However, lower requirements for atmospheric CO2 may imply that photochemical hazes were frequent during the Archean. [1] Sagan, C., & Mullen, G. Science 177, 52 (1972) [2] Hren, M.T., Tice, M.M., & Chamberlin, C.P. Nature 462, 205 (2009) [3] Blake. R.E., Chang, S.J., & Lepland, A. Nature 464, 1029 (2010) [4] Wolf, E.T., & Toon, O.B. Astrobiology 13(7), 1 (2013) [5] Rosing, M.T., Bird, D.K., Sleep, N.H., & Bjerrum, C.J. Nature 464, 744 (2010) [6] Goldblatt, C., Claire, M.W., Lenton, T.M., Matthews, A.J., Watson, A.J. Nature Geoscience 2, 891 (2009)

Wolf, E. T.; Toon, O. B.

2013-12-01

226

Incidence and hemodynamic characteristics of near-fainting in healthy 6- to 16-year old subjects  

Microsoft Academic Search

Objectives. We studied the incidence and hemodynamic characteristics of near-fainting under orthostatic stress in healthy children and teenagers.Background. Orthostatic stress testing is increasingly used to identify young subjects with unexplained syncope. However, the associated incidence of syncope and hemodynamic responses in normal young subjects are not well known.Methods. Eighty-four healthy subjects 6 to 16 years old performed forced breathing, stand-up

Catherine C. E. de Jong-de Vos van Steenwijk; Wouter Wieling; Judith M. Johannes; Mark P. Harms; Wietse Kuis; Karel H. Wessling

1995-01-01

227

Calculation of Resident Space Object Color Temperature and Emissivity- Area from MSX SPIRIT III Infrared Data: Emissive Reference Sphere Results.  

National Technical Information Service (NTIS)

This report discusses the calculation of color temperature and emissivity-area product from resident space object (RSO) observations that were obtained during a series of surveillance experiments carried out with the Midcourse Space Experiment (MSX) space...

R. L. Lambour

2002-01-01

228

The Meudon Multicolor Survey (2MS) of Centaurs and Trans-Neptunian Objects: From Visible to Infrared Colors  

Microsoft Academic Search

We present the latest results of the Meudon Multicolor Survey. This survey is aimed at characterizing the color properties and trends of Centaurs and trans-Neptunian objects. We report IJHK photometry of objects obtained with CFHT-IR at the 3.6 m Canada-France-Hawaii Telescope (Hawaii), JHK photometry with INGRID at the 4.2 m William Hershel Telescope (La Palma), and BVRI photometry with OIG

A. Doressoundiram; N. Peixinho; A. Moullet; S. Fornasier; M. A. Barucci; J.-L. Beuzit; C. Veillet

2007-01-01

229

Faint Satellites around the Nearest Bright Galaxies  

NASA Astrophysics Data System (ADS)

A long-standing problem in galaxy formation and cosmology is the relative scarcity of small galaxies. Given the abundance of small-scale CDM structure, the simplest models of galaxy formation predict there should be hundreds of faint dwarf satellites around each bright galaxy in the universe. In practice, we see only ~20 or so around each of the two bright galaxies in the Local Group. But how representative is this example? Using a new method for candidate selection, we have searched the Sloan Digital Sky Survey for potential satellites around a large set of primaries, at distances of 10-40 Mpc from us. We detect a clear clustering signal around our primaries, corresponding to an average of 4-5 satellites per system. While our satellite sample is incomplete by construction, it does probe the satellite luminosity function right down to the bottom of the "classical" dwarf range. For the first time, we are able to demonstrate that the Local Group is (almost) representative, and that the missing satellite problem is universal. We are now pursuing this work with complementary HST data from the COSMOS survey, sampling a small area to much greater distances.

Taylor, James; Speller, R.

2013-07-01

230

Complex organic matter in space: about the chemical composition of carriers of the Unidentified Infrared Bands (UIBs) and protoplanetary emission spectra recorded from certain astrophysical objects.  

PubMed

In this communication we present the basic concept that the pure PAHs (Polycyclic Aromatic Hydrocarbons) can be considered only the ideal carriers of the UIBs (Unidentified Infrared Bands), the emission spectra coming from a large variety of astronomical objects. Instead we have proposed that the carriers of UIBs and of protoplanetary nebulae (PPNe) emission spectra are much more complex molecular mixtures possessing also complex chemical structures comparable to certain petroleum fractions obtained from the petroleum refining processes. The demonstration of our proposal is based on the comparison between the emission spectra recorded from the protoplanetary nebulae (PPNe) IRAS 22272+ 5435 and the infrared absorption spectra of certain 'heavy' petroleum fractions. It is shown that the best match with the reference spectrum is achieved by highly aromatic petroleum fractions. It is shown that the selected petroleum fractions used in the present study are able to match the band pattern of anthracite coal. Coal has been proposed previously as a model for the PPNe and UIBs but presents some drawbacks which could be overcome by adopting the petroleum fractions as model for PPNe and UIBs in place of coal. A brief discussion on the formation of the petroleum-like fractions in PPNe objects is included. PMID:14979641

Cataldo, Franco; Keheyan, Yeghis; Heymann, Dieter

2004-02-01

231

HIGH-RESOLUTION MID-INFRARED SPECTROSCOPY OF NGC 7538 IRS 1: PROBING CHEMISTRY IN A MASSIVE YOUNG STELLAR OBJECT  

SciTech Connect

We present high-resolution (R = 75,000-100,000) mid-infrared spectra of the high-mass embedded young star IRS 1 in the NGC 7538 star-forming region. Absorption lines from many rotational states of C{sub 2}H{sub 2}, {sup 13}C{sup 12}CH{sub 2}, CH{sub 3}, CH{sub 4}, NH{sub 3}, HCN, HNCO, and CS are seen. The gas temperature, column density, covering factor, line width, and Doppler shift for each molecule are derived. All molecules were fit with two velocity components between -54 and -63 km s{sup -1}. We find high column densities ({approx}10{sup 16} cm{sup -2}) for all the observed molecules compared to values previously reported and present new results for CH{sub 3} and HNCO. Several physical and chemical models are considered. The favored model involves a nearly edge-on disk around a massive star. Radiation from dust in the inner disk passes through the disk atmosphere, where large molecular column densities can produce the observed absorption line spectrum.

Knez, Claudia; Lacy, John H.; Evans, Neal J. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Van Dishoeck, Ewine F. [Leiden Observatory, P.O. Box 9513, 2300 RA Leiden (Netherlands); Richter, Matthew J. [Department of Physics, University of California, Davis, One Shields Ave., Davis, CA 95616 (United States)], E-mail: claudia@astro.umd.edu

2009-05-01

232

A Consideration of Some Correlates of Fainting in Blood Donors.  

National Technical Information Service (NTIS)

In two studies of fainting in Army blood donors: Data gathered on 172 donors showed no significant differences in intelligence or educational level between reactors and nonreactors. Data on 394 donors showed no significant differences between the two grou...

L. J. Misantone

1970-01-01

233

NASA Researches the 'FaINT' Side of Sonic Booms  

NASA Video Gallery

As the latest in a continuing progression of NASA supersonics research projects aimed at reducing or mitigating the effect of sonic booms, the Farfield Investigation of No Boom Threshold, or FaINT,...

234

Infrared Astronomy and NGST  

NASA Astrophysics Data System (ADS)

The Next Generation Space Telescope (NGST), scheduled for launch in 2008, will be an infrared (0.6-10+ micron) optimized 8m telescope, passively cooled to 50K, located in an orbit about the second Lagrange point (L2). NGST is a successor to the Hubble Space Telescope (HST) and will be a key part of the NASA Origins Program. Like HST, it will be a general user observatory and will be capable of studying a wide variety of phenomena. For design purposes we are using a Design Reference Mission (DRM) which contains programs investigating; the light from the first stars and galaxies to form after the Big Bang, early supernovae and the chemical enrichment of the universe, protostellar environments within our own Galaxy, faint white dwarfs in Local Group galaxies, Kuiper Belt objects (KBOs) within the Solar system to name a few. The NGST will use many advanced technologies to realize its goals. Among these are advanced software and control systems for the telescope and its instruments. I give a brief update on the state of the NGST project and projected capabilities for this observatory.

Smith, E. P.

235

High-resolution Near-infrared Study of the Deeply Embedded Young Stellar Object S140 IRS 3  

Microsoft Academic Search

We explore the structures immediately surrounding the high-mass young stellar object S140 IRS 3 within the L1204 molecular cloud. We have obtained a bispectrum speckle interferometric K-band image with a resolution of 150 mas and a seeing-limited molecular hydrogen line emission image of IRS 3. Our speckle image resolves IRS 3 into three point sources, a close binary with separation

Thomas Preibisch; Dieter Schertl; Gerd Weigelt; Yuri Y. Balega; Michael D. Smith

2001-01-01

236

Planetcam: A Visible And Near Infrared Lucky-imaging Camera To Study Planetary Atmospheres And Solar System Objects  

NASA Astrophysics Data System (ADS)

PlanetCam is a two-channel fast-acquisition and low-noise camera designed for a multispectral study of the atmospheres of the planets (Venus, Mars, Jupiter, Saturn, Uranus and Neptune) and the satellite Titan at high temporal and spatial resolutions simultaneously invisible (0.4-1 ?m) and NIR (1-2.5 ?m) channels. This is accomplished by means of a dichroic beam splitter that separates both beams directing them into two different detectors. Each detector has filter wheels corresponding to the characteristic absorption bands of each planetary atmosphere. Images are acquired and processed using the “lucky imaging” technique in which several thousand images of the same object are obtained in a short time interval, coregistered and ordered in terms of image quality to reconstruct a high-resolution ideally diffraction limited image of the object. Those images will be also calibrated in terms of intensity and absolute reflectivity. The camera will be tested at the 50.2 cm telescope of the Aula EspaZio Gela (Bilbao) and then commissioned at the 1.05 m at Pic-duMidi Observatory (Franca) and at the 1.23 m telescope at Calar Alto Observatory in Spain. Among the initially planned research targets are: (1) The vertical structure of the clouds and hazes in the planets and their scales of variability; (2) The meteorology, dynamics and global winds and their scales of variability in the planets. PlanetCam is also expected to perform studies of other Solar System and astrophysical objects. Acknowledgments: This work was supported by the Spanish MICIIN project AYA2009-10701 with FEDER funds, by Grupos Gobierno Vasco IT-464-07 and by Universidad País Vasco UPV/EHU through program UFI11/55.

Sanchez-Lavega, Agustin; Rojas, J.; Hueso, R.; Perez-Hoyos, S.; de Bilbao, L.; Murga, G.; Ariño, J.; Mendikoa, I.

2012-10-01

237

Joint US-Japan Observations with the Infrared Space Observatory (ISO): Deep Surveys and Observations of High-Z Objects  

NASA Technical Reports Server (NTRS)

Several important milestones were passed during the past year of our ISO observing program: (1) Our first ISO data were successfully obtained. ISOCAM data were taken for our primary deep field target in the 'Lockman Hole'. Thirteen hours of integration (taken over 4 contiguous orbits) were obtained in the LW2 filter of a 3 ft x 3 ft region centered on the position of minimum HI column density in the Lockman Hole. The data were obtained in microscanning mode. This is the deepest integration attempted to date (by almost a factor of 4 in time) with ISOCAM. (2) The deep survey data obtained for the Lockman Hole were received by the Japanese P.I. (Yoshi Taniguchi) in early December, 1996 (following release of the improved pipeline formatted data from Vilspa), and a copy was forwarded to Hawaii shortly thereafter. These data were processed independently by the Japan and Hawaii groups during the latter part of December 1996, and early January, 1997. The Hawaii group made use of the U.S. ISO data center at IPAC/Caltech in Pasadena to carry out their data reduction, while the Japanese group used a copy of the ISOCAM data analysis package made available to them through an agreement with the head of the ISOCAM team, Catherine Cesarsky. (3) Results of our LW2 Deep Survey in the Lockman Hole were first reported at the ISO Workshop "Taking ISO to the Limits: Exploring the Faintest Sources in the Infrared" held at the ISO Science Operations Center in Villafranca, Spain (VILSPA) on 3-4 February, 1997. Yoshi Taniguchi gave an invited presentation summarizing the results of the U.S.-Japan team, and Dave Sanders gave an invited talk summarizing the results of the Workshop at the conclusion of the two day meeting. The text of the talks by Taniguchi and Sanders are included in the printed Workshop Proceedings, and are published in full on the Web. By several independent accounts, the U.S.-Japan Deep Survey results were one of the highlights of the Workshop; these data showed conclusively that the ISOCAM S/N continues to decrease as the square root of time for periods as long as 13 hours.

Sanders, David B.

1997-01-01

238

Star Formation and the Interstellar Medium in Nearby Tidal Streams (SAINTS): Spitzer Mid-infrared spectroscopy and Imaging of Intergalactic Star-forming Objects  

NASA Astrophysics Data System (ADS)

A spectroscopic analysis of 10 intergalactic star-forming objects (ISFOs) and a photometric analysis of 67 ISFOs in a sample of 14 interacting systems is presented. The majority of the ISFOs have relative polycyclic aromatic hydrocarbon (PAH) band strengths similar to those of nearby spiral and starburst galaxies. In contrast to what is observed in blue compact dwarfs (BCDs) and local giant H II regions in the Milky Way (NGC 3603) and the Magellanic Clouds (30 Doradus and N 66), the relative PAH band strengths in ISFOs correspond to models with a significant PAH ion fraction (<50%) and bright emission from large PAHs (~100 carbon atoms). The [Ne III]/[Ne II] and [S IV]/[S III] line flux ratios indicate moderate levels of excitation with an interstellar radiation field that is harder than the majority of the Spitzer Infrared Nearby Galaxies Survey and starburst galaxies, but softer than BCDs and local giant H II regions. The ISFO neon line flux ratios are consistent with a burst of star formation lsim6 million years ago. Most of the ISFOs have ~106 M ? of warm H2 with a likely origin in photo-dissociation regions (PDRs). Infrared Array Camera photometry shows the ISFOs to be bright at 8 ?m, with one-third having [4.5] - [8.0] > 3.7, i.e., enhanced non-stellar emission, most likely due to PAHs, relative to normal spirals, dwarf irregulars, and BCD galaxies. The relative strength of the 8 ?m emission compared to that at 3.6 ?m or 24 ?m separates ISFOs from dwarf galaxies in Spitzer two-color diagrams. The infrared power in two-thirds of the ISFOs is dominated by emission from grains in a diffuse interstellar medium. One in six ISFOs have significant emission from PDRs, contributing ~30%-60% of the total power. ISFOs are young knots of intense star formation.

Higdon, S. J. U.; Higdon, J. L.; Smith, B. J.; Hancock, M.

2014-06-01

239

Deep imaging of the field of the z = 4.9 quasar PC 1247+3406, and faint galaxy counts in the K band with the Keck telescope  

NASA Technical Reports Server (NTRS)

We present deep images in the K(sub s) band of the field of the quasar PC 1247+3406 at z = 4.897, obtained using the near-infrared camera on the W. M. Keck telescope. A number of faint sources have been detected, some of which appear to be quite red. Their nature and redshifts remain uncertain at this time. These data are combined with deep Keck infrared images of five additional fields and present galaxy counts reaching down to K(sub s) = 22 mag, comparable to the deepest K-band surveys to date. The data presented here are in good agreement with the Hawaii Deep Survey and represent the first independent verification of those results. The slope of the log N-log S relation derived from these data agrees well with the Hawaii Deep Survey, while the counts are slightly higher, especially at the faintest levels probed here. This may be due to a presence of groups or clusters around the target objects at high redshifts.

Soifer, B. T.; Matthews, K.; Djorgovski, S.; Larkin, J.; Graham, J. R.; Harrison, W.; Jernigan, G.; Lin, S.; Nelson, J.; Neugebauer, G.

1994-01-01

240

The origin of mid-infrared emission in massive young stellar objects: multi-baseline VLTI observations of W33A  

NASA Astrophysics Data System (ADS)

Aims: In this paper we aim to determine the structure on 100 AU scales of the massive young stellar object W33A, using interferometric observations in the mid-infrared. This emission could be caused by a variety of elements, for example, the inner protostellar envelope, outflow cavity walls, or a dusty or gaseous accretion disk. Methods: We used the Unit Telescopes of the VLT Interferometer in conjunction with the MIDI instrument to obtain spectrally dispersed visibilities in the N-band on 4 baselines with an angular resolution between 25 and 60 milli-arcsec (equivalent to 95 and 228 AU at 3.8 kpc). The visibility spectra and spectral energy distribution were compared to 2D-axi-symmetric dust radiative transfer models with a geometry that includes a rotationally flattened envelope and outflow cavities. We assumed an O 7.5 ZAMS star as the central source, consistent with the observed bolometric luminosity. The observations were compared to models with and without (dusty and gaseous) accretion disks. Results: The visibilities are between 5% and 15%, and the non-spherically symmetric emitting structure has a typical size of 100 AU. A satisfactory model is constructed to reproduce the visibility spectra for each (u,v) point. It fits the N-band flux spectrum, the mid-infrared slope, the far-infrared peak, and the (sub)mm regime of the SED. It produces a 350 ?m morphology consistent with the observations. Conclusions: The mid-infrared emission of W33A on 100 AU scales is dominated by the irradiated walls of the cavity sculpted by the outflow. The protostellar envelope has an equivalent mass infall rate of 7.5 × 10-4 M? yr-1, and an outflow opening angle of 2? = 20°. The visibilities rule out the presence of any dust disk with total (gas and dust) mass more than 0.01 M?. Within the model, this implies a disk dot{M}_acc of less than 1.1 × 10-7 (?/0.01) M? yr-1, where ? is the viscosity of the Shakura-Sunyaev prescription. However, optically thick accretion disks, which are inside the dust sublimation radius, are allowed to accrete at rates equalling the envelope's mass infall rate (up to 10-3 M? yr-1) without substantially affecting the visibilities due to the extinction by the extremely massive envelope of W33A. Based on observations with the VLTI, proposal 381.C-0602.

de Wit, W. J.; Hoare, M. G.; Oudmaijer, R. D.; Lumsden, S. L.

2010-06-01

241

VY Monocerotis and the IC 446 region - Far-infrared and submillimeter images of a massive young stellar object and its environment  

NASA Technical Reports Server (NTRS)

The reflection nebulae IC 446 has been mapped in an 8 x 8-arcmin area at 100, 160, and 370 microns using 32-channel bolometer-array detectors on the 0.9-m telescope of the NASA Kuiper Airborne Observatory and the 3-m telescope of the NASA Infrared Telescope Facility. These data have been combined with IRAS profiles at 12, 25, 60, and 100 microns to investigate the morphology and energetics of the region. The FIR through submm emission in the neighborhood of IC 446 is composed of three components: a compact point source associated with the young stellar object VY Mon, warm extended emission associated with dust in the reflection nebula IC 446, and cold extended emission associated with a dark absorption nebula or globule.

Casey, S. C.; Harper, D. A.

1990-01-01

242

Faint electric dynamic forces in atmosphere is a possible precursor for a Seismic events phenomena  

NASA Astrophysics Data System (ADS)

The objective of this paper is to monitor the propagation of faint electric forces (D.C. potentials) in Athens' atmosphere before an earthquake. Many authors refer to radio emissions (ELF,HF,VLF,UHF ) before an event. Several other researches have been done with ICE (Instrument Champ Electrique), measurement of quasi-continuous electric fields and electric components of waves, from DC up to 3.5 MHz, or IMSC (Measuring the magnetic components of waves), for measuring magnetic field from a few Hz up to 18 kHz. More studies, within the last twenty years are correlated also with monitoring underground electromagnetic fields from different countries, but few are dealing with D.C.field. The concept is that, the aerosols are injected into the lower atmosphere due to intensifying soil gas content during the increase of seismic activity. At our station in Athens, a continuous monitoring has been conducted by three D.C.detectors which follow the ionosphere variations of the electric field daily, for the years 2007-2008. Multiple antennas have been posted and tested up to the height of thirty meters above the ground. The faint electro potentials received, had been continuously registered by two electrometers. A cross over study of aerosols simulation has been simultaneously done with photo detectors. For this purpose an array of four photo diodes, posted in infrared and visible band in function, and was connected to electro meters too. Several approaches have been taken in past years by researchers attempting to correlate changes in geophysical parameters with earthquake phenomena. In particular, many works examine possible connections of Geoelectric Field (Long and Sort Term Geoelectric Potential) variations to seismic activity and their possible use as precursors of seismic events. Long Term Geoelectric Potential (LTGP) acquisition data consists of potential difference measured between pairs of electrodes placed in the ground at specific location and distance. The electric field is continuously monitored, usually in two perpendicular directions (e.g. N-S and E-W), by two pairs of electrodes, each corresponding to a separate channel. Here we examine such possible correlations between recorded Long Term Geoelectric Potential (LTGP) acquisition data and the seismic activity observed during the same period. In collaboration with the University of Athens, Laboratory of Climatology and Atmospheric Environment and according their given data, we avoided measurements during periods of rain, snow, storms, lightning or extreme variations of temperature and atmospheric pressure. During these observations we observed an enormous variation in the voltage signals and several potential peaks were registered before the quakes in both detectors and photodiodes. The variations noted before the events, become with an optimum peak between four hours to fourteen days. All cases are related with eight earthquakes, registered in the southern part of Greece. Our conclusions demonstrate that charged aerosol emissions in the atmosphere are possible to influence and increase electro potentials before an earthquake event, under certain atmospheric conditions.

Grigoropoulos, K. N.; Nastos, P. T.; Tselentis, G.; Saragas, E.; Ifantis, A.

2009-04-01

243

Water in star-forming regions with Herschel (WISH). III. Far-infrared cooling lines in low-mass young stellar objects  

NASA Astrophysics Data System (ADS)

Context. Understanding the physical phenomena involved in the earlierst stages of protostellar evolution requires knowledge of the heating and cooling processes that occur in the surroundings of a young stellar object. Spatially resolved information from its constituent gas and dust provides the necessary constraints to distinguish between different theories of accretion energy dissipation into the envelope. Aims. Our aims are to quantify the far-infrared line emission from low-mass protostars and the contribution of different atomic and molecular species to the gas cooling budget, to determine the spatial extent of the emission, and to investigate the underlying excitation conditions. Analysis of the line cooling will help us characterize the evolution of the relevant physical processes as the protostar ages. Methods. Far-infrared Herschel-PACS spectra of 18 low-mass protostars of various luminosities and evolutionary stages are studied in the context of the WISH key program. For most targets, the spectra include many wavelength intervals selected to cover specific CO, H2O, OH, and atomic lines. For four targets the spectra span the entire 55-200 ?m region. The PACS field-of-view covers ~47" with the resolution of 9.4". Results. Most of the protostars in our sample show strong atomic and molecular far-infrared emission. Water is detected in 17 out of 18 objects (except TMC1A), including 5 Class I sources. The high-excitation H2O 818-707 63.3 ?m line (Eu/kB = 1071 K) is detected in 7 sources. CO transitions from J = 14-13 up to J = 49 - 48 are found and show two distinct temperature components on Boltzmann diagrams with rotational temperatures of ~350 K and ~700 K. H2O has typical excitation temperatures of ~150 K. Emission from both Class 0 and I sources is usually spatially extended along the outflow direction but with a pattern that depends on the species and the transition. In the extended sources, emission is stronger off source and extended on &?10,000 AU scales; in the compact sample, more than half of the flux originates within 1000 AU of the protostar. The H2O line fluxes correlate strongly with those of the high-J CO lines, both for the full array and for the central position, as well as with the bolometric luminosity and envelope mass. They correlate less strongly with OH fluxes and not with [O I] fluxes. In contrast, [O I] and OH often peak together at the central position. Conclusions. The PACS data probe at least two physical components. The H2O and CO emission very likely arises in non-dissociative (irradiated) shocks along the outflow walls with a range of pre-shock densities. Some OH is also associated with this component, most likely resulting from H2O photodissociation. UV-heated gas contributes only a minor fraction to the CO emission observed by PACS, based on the strong correlation between the shock-dominated CO 24-23 line and the CO 14-13 line. [O I] and some of the OH emission probe dissociative shocks in the inner envelope. The total far-infrared cooling is dominated by H2O and CO, with the fraction contributed by [O I] increasing for Class I sources. Consistent with previous studies, the ratio of total far-infrared line emission over bolometric luminosity decreases with the evolutionary state. Appendices A-J are available in electronic form at http://www.aanda.org

Karska, A.; Herczeg, G. J.; van Dishoeck, E. F.; Wampfler, S. F.; Kristensen, L. E.; Goicoechea, J. R.; Visser, R.; Nisini, B.; San José-García, I.; Bruderer, S.; ?niady, P.; Doty, S.; Fedele, D.; Y?ld?z, U. A.; Benz, A. O.; Bergin, E.; Caselli, P.; Herpin, F.; Hogerheijde, M. R.; Johnstone, D.; Jørgensen, J. K.; Liseau, R.; Tafalla, M.; van der Tak, F.; Wyrowski, F.

2013-04-01

244

A PECULIAR FAINT SATELLITE IN THE REMOTE OUTER HALO OF M31  

SciTech Connect

We present Hubble Space Telescope imaging of a newly discovered faint stellar system, PAndAS-48, in the outskirts of the M31 halo. Our photometry reveals this object to be comprised of an ancient and very metal-poor stellar population with age {approx}> 10 Gyr and [Fe/H] {approx}< -2.3. Our inferred distance modulus (m - M){sub 0} = 24.57 {+-} 0.11 confirms that PAndAS-48 is most likely a remote M31 satellite with a three-dimensional galactocentric radius of 149{sup +19}{sub -8} kpc. We observe an apparent spread in color on the upper red giant branch that is larger than the photometric uncertainties should allow, and briefly explore the implications of this. Structurally, PAndAS-48 is diffuse, faint, and moderately flattened, with a half-light radius r{sub h}=26{sup +4}{sub -3} pc, integrated luminosity M{sub V} = -4.8 {+-} 0.5, and ellipticity {epsilon}=0.30{sup +0.08}{sub -0.15}. On the size-luminosity plane it falls between the extended globular clusters seen in several nearby galaxies and the recently discovered faint dwarf satellites of the Milky Way; however, its characteristics do not allow us to unambiguously classify it as either type of system. If PAndAS-48 is a globular cluster then it is among the most elliptical, isolated, and metal-poor of any seen in the Local Group, extended or otherwise. Conversely, while its properties are generally consistent with those observed for the faint Milky Way dwarfs, it would be a factor of {approx}2-3 smaller in spatial extent than any known counterpart of comparable luminosity.

Mackey, A. D.; Dotter, A. [Research School of Astronomy and Astrophysics, Australian National University, Mount Stromlo Observatory, via Cotter Road, Weston, ACT 2611 (Australia); Huxor, A. P. [Astronomisches Rechen-Institut, Universitaet Heidelberg, Moenchhofstrasse 12-14, D-69120 Heidelberg (Germany); Martin, N. F.; Ibata, R. A. [Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'Universite, F-67000 Strasbourg (France); Ferguson, A. M. N. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); McConnachie, A. W. [NRC Herzberg Institute for Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Irwin, M. J. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Lewis, G. F. [Sydney Institute for Astronomy, School of Physics, A28, University of Sydney, NSW 2006 (Australia); Sakari, C. M.; Venn, K. A. [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 1A1 (Canada); Tanvir, N. R., E-mail: dougal@mso.anu.edu.au [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

2013-06-20

245

SN 2009E: a faint clone of SN 1987A  

NASA Astrophysics Data System (ADS)

Context.1987A-like events form a rare sub-group of hydrogen-rich core-collapse supernovae that are thought to originate from the explosion of blue supergiant stars. Although SN 1987A is the best known supernova, very few objects of this group have been discovered and, hence, studied. Aims: In this paper we investigate the properties of SN 2009E, which exploded in a relatively nearby spiral galaxy (NGC 4141) and that is probably the faintest 1987A-like supernova discovered so far. We also attempt to characterize this subgroup of core-collapse supernovae with the help of the literature and present new data for a few additional objects. Methods: The lack of early-time observations from professional telescopes is compensated by frequent follow-up observations performed by a number of amateur astronomers. This allows us to reconstruct a well-sampled light curve for SN 2009E. Spectroscopic observations which started about 2 months after the supernova explosion, highlight significant differences between SN 2009E and the prototypical SN 1987A. Modelling the data of SN 2009E allows us to constrain the explosion parameters and the properties of the progenitor star, and compare the inferred estimates with those available for the similar SNe 1987A and 1998A. Results: The light curve of SN 2009E is less luminous than that of SN 1987A and the other members of this class, and the maximum light curve peak is reached at a slightly later epoch than in SN 1987A. Late-time photometric observations suggest that SN 2009E ejected about 0.04 M? of 56Ni, which is the smallest 56Ni mass in our sample of 1987A-like events. Modelling the observations with a radiation hydrodynamics code, we infer for SN 2009E a kinetic plus thermal energy of about 0.6 foe, an initial radius of ~7 × 1012 cm and an ejected mass of ~19 M?. The photospheric spectra show a number of narrow (v ? 1800 km s-1) metal lines, with unusually strong Ba II lines. The nebular spectrum displays narrow emission lines of H, Na I, [Ca II] and [O I], with the [O I] feature being relatively strong compared to the [Ca II] doublet. The overall spectroscopic evolution is reminiscent of that of the faint 56Ni-poor type II-plateau supernovae. This suggests that SN 2009E belongs to the low-luminosity, low 56Ni mass, low-energy tail in the distribution of the 1987A-like objects in the same manner as SN 1997D and similar events represent the faint tail in the distribution of physical properties for normal type II-plateau supernovae. Appendices A and B are available in electronic form at http://www.aanda.orgFull Table 2 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/537/A141

Pastorello, A.; Pumo, M. L.; Navasardyan, H.; Zampieri, L.; Turatto, M.; Sollerman, J.; Taddia, F.; Kankare, E.; Mattila, S.; Nicolas, J.; Prosperi, E.; San Segundo Delgado, A.; Taubenberger, S.; Boles, T.; Bachini, M.; Benetti, S.; Bufano, F.; Cappellaro, E.; Cason, A. D.; Cetrulo, G.; Ergon, M.; Germany, L.; Harutyunyan, A.; Howerton, S.; Hurst, G. M.; Patat, F.; Stritzinger, M.; Strolger, L.-G.; Wells, W.

2012-01-01

246

SMA Observations on Faint Submillimeter Galaxies with S 850 < 2 mJy: Ultra Dusty Low-luminosity Galaxies at High Redshift  

NASA Astrophysics Data System (ADS)

We obtained Submillimeter Array (SMA) observations of eight faint (intrinsic 850 ?m fluxes < 2 mJy) submillimeter galaxies (SMGs) discovered in SCUBA images of the massive lensing cluster fields A370, A2390, and A1689 and detected five. In total, we obtain five SMA detections, all of which have de-lensed fluxes <1 mJy with estimated total infrared luminosities 1010-1012 L ?, comparable to luminous infrared galaxies and normal star-forming galaxies. Based on the latest number counts, these galaxies contribute ~70% of the 850 ?m extragalactic background light and represent the dominant star-forming galaxy population in the dusty universe. However, only 40^{+30}_{-16}% of our faint SMGs would be detected in deep optical or near-infrared surveys, which suggests many of these sources are at high redshifts (z >~ 3) or extremely dusty, and they are not included in current star formation history estimates.

Chen, Chian-Chou; Cowie, Lennox L.; Barger, Amy J.; Wang, Wei-Hao; Williams, Jonathan P.

2014-07-01

247

Asteroid observations with the Hubble Space Telescope and the Space Infrared Telescope Facility  

NASA Technical Reports Server (NTRS)

The ways that the asteroids can be studied with the Hubble Space Telescope (HST) and the Space Infrared Telescope Facility (SIRTF) are examined. Spectrophotometry of asteroids and the study of asteroid surfaces, shape, spins, configuration, normal reflectance, and limb darkening of asteroids using the HST are addressed along with the detection of asteroid satellites and the discovery of small asteroids using the HST. The relation of the HST to its ground system is described, as are the spectrophotometric instruments of the HST. Imaging with the HST using the Faint Object Camera and the Wide Field and Planetary Camera is examined. Finally, the SIRTF observatory, instrumentation, and capabilities for solar system science are discussed.

Zellner, B.; Wells, Eddie N.; Chapman, Clark R.; Cruikshank, D. P.

1989-01-01

248

Faint High-Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: Methods and Initial Results  

Microsoft Academic Search

We report the discovery of 39 faint high-latitude carbon stars (FHLCs) from Sloan Digital Sky Survey (SDSS) commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6objects are, in general, too

Bruce Margon; Scott F. Anderson; Hugh C. Harris; Xiaohui Fan; Donald P. Schneider; Daniel E. Vanden Berk; David J. Schlegel; Eric W. Deutsch; Zeljko Ivezic; Patrick B. Hall; Benjamin F. Williams; Arthur F. Davidsen; J. Brinkmann; István Csabai; Jeffrey J. E. Hayes; Greg Hennessy; Ellyne K. Kinney; S. J. Kleinman; Don Q. Lamb; Dan Long; Eric H. Neilsen; Robert Nichol; Atsuko Nitta; Stephanie A. Snedden; Donald G. York

2002-01-01

249

NEAR-INFRARED SPECTROSCOPY OF LOW-MASS X-RAY BINARIES: ACCRETION DISK CONTAMINATION AND COMPACT OBJECT MASS DETERMINATION IN V404 Cyg AND Cen X-4  

SciTech Connect

We present near-infrared (NIR) broadband (0.80-2.42 {mu}m) spectroscopy of two low-mass X-ray binaries: V404 Cyg and Cen X-4. One important parameter required in the determination of the mass of the compact objects in these systems is the binary inclination. We can determine the inclination by modeling the ellipsoidal modulations of the Roche-lobe filling donor star, but the contamination of the donor star light from other components of the binary, particularly the accretion disk, must be taken into account. To this end, we determined the donor star contribution to the infrared flux by comparing the spectra of V404 Cyg and Cen X-4 to those of various field K-stars of known spectral type. For V404 Cyg, we determined that the donor star has a spectral type of K3 III. We determined the fractional donor contribution to the NIR flux in the H and K bands as 0.98 {+-} 0.05 and 0.97 {+-} 0.09, respectively. We remodeled the H-band light curve from Sanwal et al. after correcting for the donor star contribution to obtain a new value for the binary inclination. From this, we determined the mass of the black hole in V404 Cyg to be M{sub BH} = 9.0{sup +0.2}{sub -0.6} M{sub sun}. We performed the same spectral analysis for Cen X-4 and found the spectral type of the donor star to be in the range K5-M1 V. The donor star contribution in Cen X-4 is 0.94 {+-} 0.14 in the H band while in the K band, the accretion disk can contribute up to 10% of the infrared flux. We remodeled the H-band light curve from Shahbaz et al., again correcting for the fractional contribution of the donor star to obtain the inclination. From this, we determined the mass of the neutron star as M{sub NS} = 1.5{sup +0.1}{sub -0.4} M{sub sun}. However, the masses obtained for both systems should be viewed with some caution since contemporaneous light curve and spectral data are required to obtain definitive masses.

Khargharia, Juthika; Froning, Cynthia S. [Department of Astrophysical and Planetary Sciences, University of Colorado, Campus Box 391, Boulder, CO 80309 (United States); Robinson, Edward L., E-mail: juthika.khargharia@colorado.ed, E-mail: elr@astro.as.utexas.ed [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

2010-06-20

250

Nucleosynthesis of the Elements in Faint Supernovae and Hypernovae  

NASA Astrophysics Data System (ADS)

We review the properties of supernovae (SNe) as a function of the progenitor's mass M. (1) Mup - 10 M? stars are super-AGB stars and resultant electron capture SNe may be Faint supernovae like Type IIn SN 2008S. (2) 10 - 12 M? stars undergo Fe-core collapse to form neutron stars (NSs) and Faint supernovae. (3) 12 M? - MBN stars undergo Fe-core collapse to form NSs and normal core-collapse supernovae. (4) MBN - 90 M? stars undergo Fe-core collapse to form Black Holes. Resultant supernovae are bifurcate into Hypernovae and Faint supernovae. The observed properties of SN 2008ha can be explained with this type of Faint supernovae. (5) 90 - 140 M? stars produce Luminous SNe, like SNe 2007bi and 2006gy. (6) 140 - 300 M? stars become pair-instability supernovae which could be Luminous supernovae (SNe 2007bi and 2006gy). (7) Very massive stars with M ? 300 M? undergo core-collapse to form intermediate mass black holes. Some SNe could be more Luminous supernovae (like SN 2006gy).

Nomoto, Ken'ichi; Moriya, Takashi; Tominaga, Nozomu

2010-03-01

251

Spectroscopy of Kuiper Belt Objects and Centaurs  

NASA Astrophysics Data System (ADS)

Due to their faintness, only a small fraction of the Kuiper Belt Objects (KBOs) and Centaurs discovered so far have been studied by spectroscopy. The spectra acquired have revealed a large variety of spectral shapes. Very few of them present absorptions. Only water ice (for a few Centaurs and KBOs) and methane (for the KBO 50000 Quaoar) have been identified unambiguously at the surface of these primitive bodies. Some weak features are found in the near infrared (for the KBO 26375 (1999DE9)) as well as in the visible (for the KBOs 47932 (2000 GN171), 38628 Huya, and 2003 AZ84) that are tentatively assigned to the presence of hydrated silicates. Other features (a narrow one due to methanol ice - or ice of a similar compound -, and a broad one that could be due to olivine) appear only in spectra of the Centaur 5145 Pholus. A few objects have heterogeneous surfaces revealed by differences in spectra recorded for different rotational phases. We will review the spectroscopic investigations and modelling attempts made so far, and see what can be deduced from them. We will then evaluate the needs for additional spectral data and laboratory data to optimize the scientific return of the observations that have been carried out. Some concluding remarks on object selections for future spectroscopic investigations and target selections for space exploration will be made.

de Bergh, C.; Barucci, A.; Doressoundiram, A.; Dotto, E.

252

CONSTRAINING MASS RATIO AND EXTINCTION IN THE FU ORIONIS BINARY SYSTEM WITH INFRARED INTEGRAL FIELD SPECTROSCOPY  

SciTech Connect

We report low-resolution near-infrared spectroscopic observations of the eruptive star FU Orionis using the Integral Field Spectrograph (IFS) Project 1640 installed at the Palomar Hale telescope. This work focuses on elucidating the nature of the faint source, located 0.''5 south of FU Ori, and identified in 2003 as FU Ori S. We first use our observations in conjunction with published data to demonstrate that the two stars are indeed physically associated and form a true binary pair. We then proceed to extract J- and H-band spectro-photometry using the damped LOCI algorithm, a reduction method tailored for high contrast science with IFS. This is the first communication reporting the high accuracy of this technique, pioneered by the Project 1640 team, on a faint astronomical source. We use our low-resolution near-infrared spectrum in conjunction with 10.2 {mu}m interferometric data to constrain the infrared excess of FU Ori S. We then focus on estimating the bulk physical properties of FU Ori S. Our models lead to estimates of an object heavily reddened, A{sub V} = 8-12, with an effective temperature of {approx}4000-6500 K. Finally, we put these results in the context of the FU Ori N-S system and argue that our analysis provides evidence that FU Ori S might be the more massive component of this binary system.

Pueyo, Laurent [Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center 3400 N. Charles Street, Baltimore, MD 21218 (United States); Hillenbrand, Lynne; Hinkley, Sasha; Dekany, Richard; Roberts, Jenny [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Vasisht, Gautam; Roberts, Lewis C. Jr.; Shao, Mike; Burruss, Rick; Cady, Eric [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Oppenheimer, Ben R.; Brenner, Douglas; Zimmerman, Neil [American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Monnier, John D. [Department of Astronomy, University of Michigan, 941 Dennison Building, 500 Church Street, Ann Arbor, MI 48109-1090 (United States); Crepp, Justin [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Parry, Ian [University of Cambridge, Institute of Astronomy, Madingley Road, Cambridge, CB3, OHA (United Kingdom); Beichman, Charles [NASA Exoplanet Science Institute, 770 South Wilson Avenue, Pasadena, CA 91225 (United States); Soummer, Remi [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2012-09-20

253

Constraining Mass Ratio and Extinction in the FU Orionis Binary System with Infrared Integral Field Spectroscopy  

NASA Astrophysics Data System (ADS)

We report low-resolution near-infrared spectroscopic observations of the eruptive star FU Orionis using the Integral Field Spectrograph (IFS) Project 1640 installed at the Palomar Hale telescope. This work focuses on elucidating the nature of the faint source, located 0farcs5 south of FU Ori, and identified in 2003 as FU Ori S. We first use our observations in conjunction with published data to demonstrate that the two stars are indeed physically associated and form a true binary pair. We then proceed to extract J- and H-band spectro-photometry using the damped LOCI algorithm, a reduction method tailored for high contrast science with IFS. This is the first communication reporting the high accuracy of this technique, pioneered by the Project 1640 team, on a faint astronomical source. We use our low-resolution near-infrared spectrum in conjunction with 10.2 ?m interferometric data to constrain the infrared excess of FU Ori S. We then focus on estimating the bulk physical properties of FU Ori S. Our models lead to estimates of an object heavily reddened, AV = 8-12, with an effective temperature of ~4000-6500 K. Finally, we put these results in the context of the FU Ori N-S system and argue that our analysis provides evidence that FU Ori S might be the more massive component of this binary system.

Pueyo, Laurent; Hillenbrand, Lynne; Vasisht, Gautam; Oppenheimer, Ben R.; Monnier, John D.; Hinkley, Sasha; Crepp, Justin; Roberts, Lewis C., Jr.; Brenner, Douglas; Zimmerman, Neil; Parry, Ian; Beichman, Charles; Dekany, Richard; Shao, Mike; Burruss, Rick; Cady, Eric; Roberts, Jenny; Soummer, Rémi

2012-09-01

254

The Stony Brook Photometric Redshifts of Faint Galaxies in the Hubble Deep Fields  

Microsoft Academic Search

We report on some aspects of the current status of our efforts to establish properties of faint galaxies by applying our photometric redshift technique to faint galaxies in the HDF and HDF-S WFPC2 and NICMOS fields.

K. M. Lanzetta; H.-W. Chen; A. Fernández-Soto; Sebastian Pascarelle; Rick Puetter; Noriaki Yahata; Amos Yahil

1999-01-01

255

Infrared standard stars  

NASA Astrophysics Data System (ADS)

The results of an observational program aimed at setting up a network of faint near-infrared standards of sufficient accuracy are reported. The network covers both northern and southern hemispheres and includes standards red enough to provide at least a limited check on color transformations. The standards are set up at J (1.2 micron), H (1.6 micron), K (2.2 microns), and L (3.5 microns), and their H2O and CO molecular absorption indices are determined. The problem of color transformations between observatories is discussed briefly. All magnitudes presented are transformed to the natural system defined by the CIT observations.

Elias, J. H.; Frogel, J. A.; Matthews, K.; Neugebauer, G.

1982-07-01

256

The Faint-end Slope of the Redshift 5.7 Ly? Luminosity Function  

NASA Astrophysics Data System (ADS)

Using new Keck DEIMOS spectroscopy, we examine the origin of the steep number counts of ultra-faint emission-line galaxies recently reported by Dressler et al. We confirm six Ly? emitters (LAEs), three of which have significant asymmetric line profiles with prominent wings extending 300-400 km s-1 redward of the peak emission. With these six LAEs, we revise our previous estimate of the number of faint LAEs in the Dressler et al. survey. Combining these data with the density of bright LAEs in the Cosmic Evolution Survey and Subaru Deep Field provides the best constraints to date on the redshift 5.7 LAE luminosity function (LF). Schechter function parameters, phi* = 4.5 × 10-4 Mpc-3, L* = 9.1 × 1042 erg s-1, and ? = -1.70, are estimated using a maximum likelihood technique with a model for slit-losses. To place this result in the context of the UV-selected galaxy population, we investigate how various parameterizations of the Ly? equivalent width distribution, along with the measured UV-continuum LF, affect shape and normalization of the Ly? LF. The nominal model, which uses z ~ 6 equivalent widths from the literature, falls short of the observed space density of LAEs at the bright end, possibly indicating a need for higher equivalent widths. This parameterization of the equivalent width distribution implies that as many as 50% of our faintest LAEs should have M UV > -18.0, rendering them undetectable in even the deepest Hubble Space Telescope surveys at this redshift. Hence, ultra-deep emission-line surveys find some of the faintest galaxies ever observed at the end of the reionization epoch. Such faint galaxies likely enrich the intergalactic medium with metals and maintain its ionized state in the post-reionization era. Observations of these objects provide a glimpse of the building blocks of present-day galaxies at an early time.

Henry, Alaina L.; Martin, Crystal L.; Dressler, Alan; Sawicki, Marcin; McCarthy, Patrick

2012-01-01

257

A CCD survey for faint high-latitude carbon stars  

NASA Technical Reports Server (NTRS)

We describe a wide-area CCD survey to search for faint high-latitude carbon (FHLC) stars. Carbon giants provide excellent probes of the structure and kinematics of the outer Galactic halo. We use two-color photometric selection with large-format CCDs to cover 52 sq deg of sky to a depth of about V = 18. Of 94 faint C star candidates from our own CCD survey, one highly ranked V = 17 candidate was found to have a strong carbon and CN bands. We estimate that, to a depth of V = 18, the surface density of FHLC stars is 0.02 deg(exp -2). An updated FHLC sample is used to constrain halo kinematic and structural parameters. Although larger samples are needed, the effective radius of FHLC giants, assuming a de Vancouleurs law distribution, is larger than that for Galactic globular clusters.

Green, Paul J.; Margon, Bruce; Anderson, Scott F.; Cook, Kem H.

1994-01-01

258

The Formation History of the Ultra-Faint Dwarf Galaxies  

NASA Astrophysics Data System (ADS)

We present early results from a Hubble Space Telescope survey of the ultra-faint dwarf galaxies. These Milky Way satellites were discovered in the Sloan Digital Sky Survey, and appear to be an extension of the classical dwarf spheroidals to low luminosities, offering a new front in the efforts to understand the missing satellite problem. Because they are the least luminous, most dark matter dominated, and least chemically evolved galaxies known, the ultra-faint dwarfs are the best candidate fossils from the early universe. The primary goal of the survey is to measure the star-formation histories of these galaxies and discern any synchronization due to the reionization of the universe. We find that the six galaxies of our survey have very similar star-formation histories, and that each is dominated by stars older than 12 Gyr.

Brown, Thomas M.; Tumlinson, J.; Geha, M. C.; Kirby, E. N.; VandenBerg, D. A.; Kalirai, J. S.; Simon, J. D.; Avila, R. J.; Munoz, R.; Guhathakurta, P.; Renzini, A.; Ferguson, H. C.; Vargas, L. C.; Gennaro, M.

2014-01-01

259

CCD time-resolved photometry of faint cataclysmic variables. IV  

NASA Technical Reports Server (NTRS)

Time-resolved CCD photometry in V, B, and the near-IR has been obtained, with average time-series length of 3 hours, for 15 certified or candidate cataclysmic-variable faint stars. Orbital periods are found in three of the stars, and nine others are noted to exhibit evidence leading toward confirmation of cataclysmic-variable status. The characteristics of PG 0917+342 and PG 2240+193 are as yet unclear.

Howell, Steve B.; Dobrzycka, Danuta; Szkody, Paula; Kreidl, Tobias J.

1991-01-01

260

Galaxy Evolution from Deep Optical and Near-Infrared Surveys  

NASA Astrophysics Data System (ADS)

We use very deep optical and near-infrared imaging surveys to set constraints on galaxy evolution models, based on the numbers, colors, and morphologies of infrared-excess galaxies that are found in the field. We concentrate on a curious population of extremely faint (K > 20) infrared-excess galaxies whose blue-optical colors are not consistent with the expectations of any passive evolution models. These ``faint red-outlier galaxies'' (FROGs) are distinct from the redder and brighter ``extremely red objects'' (EROs; R-K~=6 ). In a concerted effort to identify a good sample of FROG s and to study their properties, we used Keck/NIRC to image several independent high-galactic latitude fields. Much of the analysis presented here is drawn from a very deep 3.24 arcmin2 K-band ( Klim~24 at 3?) mosaic in the deep Westphal HST/WFPC2 pointing of the Groth Survey Strip, for which F606W and F814W data were publically available. The surface density of FROGs is found to be ~ 3.3 +/- 1 arcmin-2, more than ten times that of EROs. Whereas reliable photometric redshifts are not forthcoming without the development of more relevant models, the colors are broadly consistent with the redshift range 1.2 < z < 2.3. If placed at z ~ 1.5, FROGs occur at space densities of about 10% of the local f* space density of K-selected galaxies. To map wavelength-dependent morphologies of two FROGs, we observed a portion of our main survey field with HST/NICMOS imaging through the F160W (1.6 ?m) filter. The target was resolved into two r~=0''.6 objects with similar colors, separated by ~0''.7. This is suggestive of old and dynamically-relaxed systems. The colors of FROGs are not satisfactorily fit by dust-reddened Bruzual-Charlot models at any redshift and for a broad range of assumed star formation histories. The best possible fits are consistent with very large amounts of reddening, E(B - V) ~ 1. If the infrared-excess in EROs and FROGs is taken to be entirely due to the effects of dust, then we can estimate the upper limit of their contribution to the far infrared background. We use a range of star formation histories at different ages and representative reddening values. The integral contribution of EROs and FROGs is calculated to be no greater than ~ 1 - 10 nW m-2 sr-1. At ? ~ 100?m, 1 nW m-2 sr-1 corresponds to ~ 10% of the total measured infrared background.

Moustakas, Leonidas Alexander

1998-09-01

261

Can waterbelt climates resolve the faint young Sun paradox?  

NASA Astrophysics Data System (ADS)

Ancient sediments indicate that liquid water and primitive life were ubiquitous on the Archean Earth despite the faint young Sun. However, energy balance and radiative-convective models require improbably high greenhouse gas abundances to obtain non-glacial climates, violating constraints from geochemical data. A self-consistent solution to the faint young Sun paradox has remained elusive. Here we use the NCAR Community Atmosphere Model version 3 with thermodynamic ocean and sea ice components to simulate the climate circa 2.8 billion years ago. To maintain present day surface temperatures, 0.06 bar of CO2 in a 1 bar atmosphere is required to compensate for a 20 percent reduction in the solar constant. However, waterbelt climates having stable low latitude sea ice margins can be maintained with as little as 500 ppm of CO2 and no additional trace greenhouse species. With 5000 ppm of CO2 nearly 60 percent of the planet remains free from ice. The early Earth is resistant to hard snowball glaciations instead favoring waterbelt climates. The coexistence of a faint young Sun and a weak greenhouse does not exclude the presence of liquid water at the Archean surface.

Wolf, E. T.; Toon, O. B.

2012-12-01

262

Herschel Discovery of a New Class of Cold, Faint Debris Discs  

NASA Technical Reports Server (NTRS)

We present Herschel PACS 100 and 160 micron observations of the solar-type stars alpha Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel Open Time Key Programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 m for all three stars. HD 210277 also shows a small excess at 100 micron, while the 100 micron fluxes of alpha Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. alpha Men and HD 88230 are spatially resolved in the PACS 160 m images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from approx 115 to <= 250 AU. The estimated black body temperatures from the 100 and 160 micron fluxes are approx < 22 K, while the fractional luminosity of the cold dust is L(sub dust) / L(*) approx 10 (exp 6) close to the luminosity of the Solar-System's Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars and cannot easily be explained by invoking "classical" debris disc models.

Eiroal, C.; Marshall, J. P.; Mora, A.; Krivov, A. V.; Montesinos, B.; Absil, O.; Ardila, D.; Arevalo, M.; Augereau, J.-Ch.; Bayo, A.; Danchi, W.; del Burgo, C.; Ertel, S.; Fridlund, M.; Gonzalez-Garcia, B. M.; Heras, A. M.; Lebreton, J.; Liseau, R.; Maldonado, J.; Meeus, G.; Montes, D.; Pilbratt, G. L.; Roberge, A.; Sanz-Forcada, J.; Stapelfeldt, K.

2011-01-01

263

Herschel discovery of a new class of cold, faint debris discs  

NASA Astrophysics Data System (ADS)

We present Herschel PACS 100 and 160 ?m observations of the solar-type stars ? Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel open time key programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 ?m for all three stars. HD 210277 also shows a small excess at 100 ?m, while the 100 ?m fluxes of ? Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. Both ? Men and HD 88230 are spatially resolved in the PACS 160 ?m images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from ~115 to ? 250 AU. The estimated black body temperatures from the 100 and 160 ?m fluxes are ?22 K, and the fractional luminosity of the cold dust is Ldust/L ? ~ 10-6, close to the luminosity of the solar-system's Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars, so they cannot be explained easily invoking "classical" debris disc models. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Eiroa, C.; Marshall, J. P.; Mora, A.; Krivov, A. V.; Montesinos, B.; Absil, O.; Ardila, D.; Arévalo, M.; Augereau, J.-Ch.; Bayo, A.; Danchi, W.; Del Burgo, C.; Ertel, S.; Fridlund, M.; González-García, B. M.; Heras, A. M.; Lebreton, J.; Liseau, R.; Maldonado, J.; Meeus, G.; Montes, D.; Pilbratt, G. L.; Roberge, A.; Sanz-Forcada, J.; Stapelfeldt, K.; Thébault, P.; White, G. J.; Wolf, S.

2011-12-01

264

Herschel Discovery of a New class of Cold, Faint Debris Discs  

NASA Technical Reports Server (NTRS)

We present Herschel PACS 100 and 160 micron observations of the solar-type stars alpha Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel Open Time Key Programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 micron for all three stars. HD 210277 also shows a small excess at 100 micron. while the 100 micron fluxes of a Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. alpha Men and HD 88230 are spatially resolved in the PACS 160 micron images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from approximately 115 to <= 250 AU. The estimated black body temperatures from the 100 and 160 micron fluxes are approximately < 22 K, while the fractional luminosity of the cold dust is L(dust)/ L(star) approximates 10(exp -6), close to the luminosity of the Solar-System's Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars and cannot easily be explained by invoking "classical" debris disc models.

Eiroa, C.; Marshall, J. P.; Mora, A.; Krivov, A. V.; Montesinos, B.; Absil, O.; Ardila, D.; Arevalo, M.; Augereau, J. -Ch.; Bayo, A.; Danchi, W.; del Burgo, C.; Ertel, S.; Fridlund, M.; Gonzalez-Garcia, B. M.; Heras, A. M.; Lebreton, J.; Liseau, R.; Maldonado, J.; Meeus, G.; Montes, D.; Pilbratt, G. L.; Roberge, A.; Sanz-Forcada, J.; Stapelfeldt, K.

2012-01-01

265

The human fear-circuitry and fear-induced fainting in healthy individuals--the paleolithic-threat hypothesis.  

PubMed

The Paleolithic-Threat hypothesis reviewed here posits that habitual efferent fainting can be traced back to fear-induced allelic polymorphisms that were selected into some genomes of anatomically, mitochondrially, and neurally modern humans (Homo sapiens sapiens) in the Mid-Paleolithic because of the survival advantage they conferred during periods of inescapable threat. We posit that during Mid-Paleolithic warfare an encounter with "a stranger holding a sharp object" was consistently associated with threat to life. A heritable hardwired or firm-wired (prepotentiated) predisposition to abruptly increase vagal tone and collapse flaccidly rather than freeze or attempt to flee or fight in response to an approaching sharp object, a minor injury, or the sight of blood, may have evolved as an alternative stress-induced fear-circuitry response. Such a stable (balanced) polymorphism for the hemodynamically "paradoxical" flaccid-immobility in response to these stimuli may have increased some non-combatants' chances of survival. This is consistent with the unusual age and sex pattern of fear-induced fainting. The Paleolithic-Threat hypothesis also predicts a link to various hypo-androgenic states (e. g. low dehydroxy-epiandrosterone-sulfate. We offer five predictions testable via epidemiological, clinical, and ethological/ primatological methods. The Paleolithic-Threat hypothesis has implications for research in the aftermath of man-made disasters, such as terrorism against civilians, a traumatic event in which this hypothesis predicts epidemics of fear-induced fainting. PMID:15944875

Bracha, H Stefan; Bracha, Adam S; Williams, Andrew E; Ralston, Tyler C; Matsukawa, Jennifer M

2005-06-01

266

The optical night sky at low surface brightness: High latitude dust and faint field galaxies  

NASA Astrophysics Data System (ADS)

Deep CCD imaging in U, Bj, R, and I, over angular scales ranging from a few arcseconds to over 30 arcminutes, is used to study two classes of astronomical objects that produce fluctuations in the dark night sky background: interstellar dust clouds at high Galactic latitudes, initially identified by their thermal re-radiation of ambient starlight as IRAS 100 microns cirrus; and a population of faint blue field galaxies, which, at 30 B(subj) mag/arcsec, begin to fill up the field of view. A CCD mosaicing technique, designed to allow imaging of large areas of the sky at low light levels, was used to study the cirrus morphology. The scattering and re-emission of optical radiation from the cirrus are investigated, with the goal of learning more about the environment of these clouds and the physical processes involved. The cirrus is extremely red in both Bj-R and R-I, much redder than a simple scattering model predicts. The excess R and I band flux is probably the result of luminescence in small hydrogenated dust grains. This very red color appears to be a universal signature of optically thin dust clouds at high latitudes, and should enable them to be distinguished from the second component, aggregates of faint blue galaxies. These galaxies dominate the number counts in the field, and the U band count slope is even steeper than that in Bj. The colors, over the wavelength range 3600 A to 1 micron, are indicative of fairly recent evolution.

Guhathakurta, Puragra

267

SAX J1711.6-3808: a faint X-ray transient harboring a black hole?  

NASA Astrophysics Data System (ADS)

Thanks to dedicated X-ray monitoring observations of the Galactic bulge with the Wide Field Cameras on BeppoSAX, several tens of faint X-ray transients have been discovered with peak fluxes that are just a few percent of that of classical X-ray novae. Most of these faint transients exhibit type-I X-ray bursts and, thus, harbor a neutron star. A few cases do not, like SAX J1711.6-3808 which was active between January and May 2001. We followed up this transient with BeppoSAX, RXTE and XMM-Newton. The 1-200 keV spectrum is characterized by Comptonization, a transient soft excess and a 2.6 keV (FWHM) broad emission feature at the Fe-K line complex whose flux peaks in tandem with that of the soft excess. The emission feature is reminiscent to that seen in the classical black hole candidate Cyg X-1. We propose that SAX J1711.6-3808 contains a black hole, and that the broadness of the emission feature is related to Doppler shifts due to orbital motion of the emitting material around the compact object. This would be the 4th time that a broad Fe-K emission feature has been detected in a Galactic black hole.

in't Zand, Jean; Markwardt, Craig; Santos-Lleo, Maria; Bazzano, Angela; Cocchi, Massimo; Cornelisse, Remon; Heise, John; Kuulkers, Erik; Natalucci, Lorenzo; Sanchez-Fernandez, Celia; Swank, Jean; Ubertini, Pietro

2002-04-01

268

Magellan/MMIRS near-infrared multi-object spectroscopy of nebular emission from star-forming galaxies at 2 < z < 3  

NASA Astrophysics Data System (ADS)

Aims: To investigate the ingredients, which allow star-forming galaxies to present Ly? line in emission, we studied the kinematics and gas phase metallicity of the interstellar medium. Methods: We used multi-object near-infrared spectroscopy with Magellan/MMIRS to study nebular emission from z ? 2-3 star-forming galaxies discovered in three MUSYC fields. Results: We detected emission lines from four active galactic nuclei and 13 high-redshift star-forming galaxies, including H? lines down to a flux of (4 ± 1)E-17 erg s-1 cm-2. This yielded seven new redshifts. The most common emission line detected is [OIII]5007, which is sensitive to metallicity. We were able to measure metallicity (Z) for two galaxies and to set upper (lower) limits for another two (two). The metallicity values are consistent with 0.3 < Z/Z? < 1.2, 12 + log (O/H) ~ 8.2-8.8. Comparing the Ly? central wavelength with the systemic redshift, we find ?vLy? - [OIII] 5007 = 70-270 km s-1. Conclusions: High-redshift star-forming galaxies, Ly? emitting (LAE) galaxies, and H? emitters appear to be located in the low mass, high star-formation rate (SFR) region of the SFR versus stellar mass diagram, confirming that they are experiencing burst episodes of star formation, which are building up their stellar mass. Their metallicities are consistent with the relation found for z ? 2.2 galaxies in the Z versus stellar mass plane. The measured ?vLy? - [OIII] 5007 values imply that outflows of material, driven by star formation, could be present in the z ~ 2-3 LAEs of our sample. Comparing with the literature, we note that galaxies with lower metallicity than ours are also characterized by similar ?vLy? - [OIII] 5007 velocity offsets. Strong F([OIII]5007) is detected in many Ly? emitters. Therefore, we propose the F(Ly?)/F([OIII]5007) flux ratio as a tool for the study of high-redshift galaxies; while influenced by metallicity, ionization, and Ly? radiative transfer in the ISM, it may be possible to calibrate this ratio to primarily trace one of these effects. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, ChileTables 4-6 and Appendices are available in electronic form at http://www.aanda.org

Guaita, L.; Francke, H.; Gawiser, E.; Bauer, F. E.; Hayes, M.; Östlin, G.; Padilla, N.

2013-03-01

269

The Most Powerful Cosmic Telescopes for Constraining the Faint-end Slope of the z > 7 Luminosity Function  

NASA Astrophysics Data System (ADS)

It is likely that intergalactic hydrogen was reionized by redshifts of 6 < z < 10, but it is not known whether the flux density of UV photons from the earliest galaxies was sufficient to do so. Measurements of the faint end slope of the luminosity function at these redshifts can help to address this question. I explore the use of the densest galaxy fields to lens faint objects into detectability, increasing source counts and providing improved constraints on dlog N / dlog L. First, I present galaxy spectroscopy for the first two dense beams identified from the SDSS. We have now confirmed that these beams have integrated masses of 3-4 x 1015 solar masses, surpassing even the most massive single cluster lensing fields. This increased mass should result in 50-1000% more detected sources at z > 7 than other current methods with equivalent exposure time. Second, I compare the high-redshift detection efficiencies of lensing and blank fields including realistic assumptions for the intrinsic sizes and morphologies of sources at z > 7. We find that there are heretofore uncorrected biases introduced by lensing due to the difficulty of detecting faint, highly elongated objects at high magnification. To interpret high-redshift, magnified number counts correctly, incompleteness due to this bias must be addressed with lensing simulations. The correction for incompleteness near the detection limit may exceed a factor of ten. Including finite source size and realistic shape assumptions, luminosity function slopes must be steeper than -dlog N / dlog L 2 at the faint end for cosmic telescopes to surpass blank field surveys in z > 7 detection efficiency. Prepared by LLNL under Contract DE-AC52-07NA27344.

Ammons, Stephen; Wong, K. C.; Zabludoff, A. I.; Keeton, C. R.; French, D.

2012-01-01

270

Near infrared observations of TNOs with SINFONI  

NASA Astrophysics Data System (ADS)

The trans-Neptunian objects are probably the most primitive objects in the Solar System and their study carries important clues about the history of formation and evolution of our planetary system. From 2001 the Meudon group started an observational campaign at VLT/ESO to observe by spectroscopy these faint and distant objects to investigate their surface composition. Recently, a new instrument has been installed, the Spectrograph for INtegral Field Observations in the Near Infrared, SINFONI. This instrument allows to obtain cubes of data with spectra of medium resolution of TNOs, useful to search for subtle absorption features. Here we present data for three plutinos: 26375 (1999 DE9), 38628 Huya, and 47932 (2000 GN171) searching for possible rotational inhomogeneities and/or features on their spectra. We also present data of the distant TNO 90377 Sedna searching for absorption bands, such as the band at 2.3 ?m, probably due to methane ice, proposed by Barucci et al. (2005, A&A, 439, L1). A comparison with previous published observations is performed and the results discussed. A parallel presentation of SINFONI data is presented in this same conference by de Bergh et al. in the frame of the study of 136108 (2003 EL61).

Alvarez-Candal, A.; Barucci, M. A.; Merlin, F.; Guibert, A.; de Bergh, C.

2007-08-01

271

Visible and Near-Infrared Diffuse Reflectance Spectra of Pyroxenes as Applied to Remote Sensing of Solid Objects in the Solar System  

Microsoft Academic Search

Spin-allowed Fe z+ absorption bands occur in the visible and near-infrared diffuse reflectance spectra of most pyroxenes. The wavelengths of the bands centered near 1 #m and 2 #m vary as functions of pyroxene composition, making possible mineralogical and chemical deductions based on spectral reflectance curves. Typically, pyroxene bands are well developed in relation to absorption features in the spectra

John B. Adams

1974-01-01

272

Deceleration of faint photographic meteors and the density of meteoroids  

SciTech Connect

The authors have performed mathematical modeling of observed deceleration of faint photographic meteors, and their heights of disappearance, in the framework of a simplified theory of quasicontinuous crushing of meteoroids. This modeling has enabled them to estimate the density of the parent meteoroids and the mass of large fragments. Out of 92 sporadic meteors which they have considered, they have found that 57 were created by meteoroids with characteristic similar to those of carbonaceous chondrites, 20 came from meteoroids similar to ordinary stony meteorites (chondrites) 8 came from iron meteoroids, 4 from stony-iron meteoroids, and 3 of the meteors came from very porous meteoroids of the dust clump type.

Lebedinets, V.N.

1987-07-01

273

Infrared radiant heating  

Microsoft Academic Search

Retrofitting convective forced air heating systems with infrared (IR) systems can save as much as 50 percent of the total heating bill. Infrared heating is more efficient for two reasons: it can be directed to heat only occupied space; and it does not heat the air in a space, it only heats people and objects. Infrared heating works best where

S. Cannon; M. Rocha

1996-01-01

274

Infrared Images  

NASA Technical Reports Server (NTRS)

Earth objects emit natural radiation invisible to the unaided human eye, but visible to infrared scanning devices such as the device developed by Inframetrics, Inc. Such devices serve a number of purposes ranging from detection of heat loss in buildings for energy conservation measures, to examining heat output of industrial machinery for trouble shooting and preventive maintenance. Representative of system is Model 525, a small, lightweight field instrument that scans infrared radiation and translates its findings to a TV picture of the temperature pattern in the scene being viewed. An accessory device permits viewing the thermal radiation in color.

1980-01-01

275

ARACHNID: A prototype object-oriented database tool for distributed systems  

NASA Technical Reports Server (NTRS)

This paper discusses the results of a Phase 2 SBIR project sponsored by NASA and performed by MIMD Systems, Inc. A major objective of this project was to develop specific concepts for improved performance in accessing large databases. An object-oriented and distributed approach was used for the general design, while a geographical decomposition was used as a specific solution. The resulting software framework is called ARACHNID. The Faint Source Catalog developed by NASA was the initial database testbed. This is a database of many giga-bytes, where an order of magnitude improvement in query speed is being sought. This database contains faint infrared point sources obtained from telescope measurements of the sky. A geographical decomposition of this database is an attractive approach to dividing it into pieces. Each piece can then be searched on individual processors with only a weak data linkage between the processors being required. As a further demonstration of the concepts implemented in ARACHNID, a tourist information system is discussed. This version of ARACHNID is the commercial result of the project. It is a distributed, networked, database application where speed, maintenance, and reliability are important considerations. This paper focuses on the design concepts and technologies that form the basis for ARACHNID.

Younger, Herbert; Oreilly, John; Frogner, Bjorn

1994-01-01

276

Objective assessment of skin tightening in Asians using a water-filtered near-infrared (1,000-1,800 nm) device with contact-cooling and freezer-stored gel  

PubMed Central

Background Near-infrared has been shown to penetrate deeper than optical light sources independent of skin color, allowing safer treatment for the Asian skin type. Many studies have indicated the efficacy of various types of devices, but have not included a sufficiently objective evaluation. In this study, we used three-dimensional imaging for objective evaluation of facial skin tightening using a water-filtered near-infrared device. Methods Twenty Japanese patients were treated with the water-filtered near-infrared (1,000–1,800 nm) device using a contact-cooling and nonfreezing gel stored in a freezer. Three-dimensional imaging was performed, and quantitative volume measurements were taken to evaluate the change in post-treatment volume. The patients then provided their subjective assessments. Results Objective assessments of the treated cheek volume evaluated by a three-dimensional color schematic representation with quantitative volume measurements showed significant improvement 3 months after treatment. The mean volume reduction at the last post-treatment visit was 2.554 ± 0.999 mL. The post-treatment volume was significantly reduced compared with the pretreatment volume in all patients (P < 0.0001). Eighty-five percent of patients reported satisfaction with the improvement of skin laxity, and 80% of patients reported satisfaction with improvement of rhytids, such as the nasolabial folds. Side effects, such as epidermal burns and scar formation, were not observed throughout the study. Conclusion The advantages of this water-filtered near-infrared treatment are its high efficacy for skin tightening, associated with a minimal level of discomfort and minimal side effects. Together, these characteristics facilitate our ability to administer repeated treatments and provide alternative or adjunctive treatment for patients, with improved results. This study provides a qualitative and quantitative volumetric assessment, establishing the ability of this technology to reduce volume through noninvasive skin tightening.

Tanaka, Yohei; Tsunemi, Yuichiro; Kawashima, Makoto; Tatewaki, Naoto; Nishida, Hiroshi

2013-01-01

277

Hubble Space Telescope faint object spectrograph instrument handbook, version 5.0  

NASA Technical Reports Server (NTRS)

This version of the FOS Instrument Handbook is for the refurbished telescope, which is affected by an increase in throughput, especially for the smaller apertures, a decrease in efficiency due to the extra reflections of the COSTAR optics, and a change in focal length. The improved PSF affects all exposure time calculations due to better aperture throughputs and increases the spectral resolution. The extra reflections of COSTAR decrease the efficiency by 10-20 percent. The change in focal length affects the aperture sizes as projected on the sky. The aperture designations that are already in use both in the exposure logsheets and in the project data base (PDB) have not been changed. Apertures are referred to here by their size, followed by the designation used on the exposure logsheet.

Kinney, A. L. (editor)

1994-01-01

278

Guaranteed time observations support for Faint Object Spectrograph (FOS) on HST  

NASA Technical Reports Server (NTRS)

The goals of the GTO effort are for investigations defined in previous years by the IDT to be carried out as HST observations and for the results to be communicated to the scientific community and to the public. The search for possible black holes in the nuclei of both normal and active nucleus galaxies has had to be delayed to the post-servicing era. FOS spectropolarimetric observations of the nuclear region of the peculiar Seyfert galaxy Mrk 231 reveal that the continuum polarization peaks at 18% in the near UV and then declines rapidly toward shorter wavelengths. The papers on the absorption line analysis for our galactic halo address the spatial distribution of high and intermediate level ions in the halo and illustrate the patchy and heterogeneous nature of the halo. The papers on the scattering characteristics of the HST/FOS have provided us with data that shows that the HST mirror surfaces are quite smooth, even at the UV wavelengths. WF-PC and FOC images of the halo PN K648 have been fully analyzed.

Harms, Richard

1994-01-01

279

The Munich Near-Infrared Cluster Survey - IV. Biases in the completeness of near-infrared imaging data  

NASA Astrophysics Data System (ADS)

We present the results of completeness simulations for the detection of point sources as well as redshifted elliptical and spiral galaxies in the K'-band images of the Munich Near-Infrared Cluster Survey (MUNICS). The main focus of this work is to quantify the selection effects introduced by threshold-based object detection algorithms used in deep imaging surveys. Therefore, we simulate objects obeying the well-known scaling relations between effective radius and central surface brightness, for both de Vaucouleurs and exponential profiles. The results of these simulations, while presented for the MUNICS project, are applicable in a much wider context to deep optical and near-infrared selected samples. We investigate the detection probability as well as the reliability for recovering the true total magnitude with Kron-like (adaptive) aperture photometry. The results are compared with the predictions of the visibility theory of Disney and Phillipps in terms of the detection rate and the lost-light fraction. Additionally, the effects attributable to seeing are explored. The results show a bias against detecting high-redshifted massive elliptical galaxies in comparison to disc galaxies with exponential profiles, and that the measurements of the total magnitudes for intrinsically bright elliptical galaxies are systematically too faint. Disc galaxies, in contrast, show no significant offset in the magnitude measurement of luminous objects. Finally, we present an analytic formula to predict the completeness of point sources using only basic image parameters.

Snigula, J.; Drory, N.; Bender, R.; Botzler, C. S.; Feulner, G.; Hopp, U.

2002-11-01

280

Faint High-Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: Methods and Initial Results  

NASA Astrophysics Data System (ADS)

We report the discovery of 39 faint high-latitude carbon stars (FHLCs) from Sloan Digital Sky Survey (SDSS) commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6objects are, in general, too faint and too warm to be effectively identified in other modern surveys such as the Two Micron All Sky Survey, nor are their red/near-IR colors particularly distinctive. The implied surface density of FHLCs in this magnitude range is uncertain at this preliminary stage of the survey because of completeness corrections but is clearly greater than 0.05 deg-2. At the completion of the Sloan survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper-motion measures for each object, indicating that the sample is a mixture of extremely distant (greater than 100 kpc) halo giant stars, useful for constraining halo dynamics, and members of the recently recognized exotic class of very nearby dwarf carbon (dC) stars. The broadband colors of the two populations are indistinguishable. Motions, and thus dC classification, are inferred for 40%-50% of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. The observed kinematics suggest that the dwarfs occupy distinct halo and disk populations. The coolest FHLCs with detectable proper motions in our sample also display multiple CaH bands in their spectra. It may be that CaH is another long-sought, low-resolution, spectroscopic luminosity discriminant between dC's and distant faint giants, at least for the cooler stars.

Margon, Bruce; Anderson, Scott F.; Harris, Hugh C.; Strauss, Michael A.; Knapp, G. R.; Fan, Xiaohui; Schneider, Donald P.; Vanden Berk, Daniel E.; Schlegel, David J.; Deutsch, Eric W.; Ivezi?, Željko; Hall, Patrick B.; Williams, Benjamin F.; Davidsen, Arthur F.; Brinkmann, J.; Csabai, István; Hayes, Jeffrey J. E.; Hennessy, Greg; Kinney, Ellyne K.; Kleinman, S. J.; Lamb, Don Q.; Long, Dan; Neilsen, Eric H.; Nichol, Robert; Nitta, Atsuko; Snedden, Stephanie A.; York, Donald G.

2002-09-01

281

Object Oriented Learning Objects  

ERIC Educational Resources Information Center

We apply the object oriented software engineering (OOSE) design methodology for software objects (SOs) to learning objects (LOs). OOSE extends and refines design principles for authoring dynamic reusable LOs. Our learning object class (LOC) is a template from which individualised LOs can be dynamically created for, or by, students. The properties…

Morris, Ed

2005-01-01

282

Infrared microscope inspection apparatus  

DOEpatents

Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface.

Forman, Steven E. (Framingham, MA); Caunt, James W. (Concord, MA)

1985-02-26

283

Infrared microscope inspection apparatus  

DOEpatents

Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface. 4 figs.

Forman, S.E.; Caunt, J.W.

1985-02-26

284

THE FAINT-END SLOPE OF THE REDSHIFT 5.7 Ly{alpha} LUMINOSITY FUNCTION  

SciTech Connect

Using new Keck DEIMOS spectroscopy, we examine the origin of the steep number counts of ultra-faint emission-line galaxies recently reported by Dressler et al. We confirm six Ly{alpha} emitters (LAEs), three of which have significant asymmetric line profiles with prominent wings extending 300-400 km s{sup -1} redward of the peak emission. With these six LAEs, we revise our previous estimate of the number of faint LAEs in the Dressler et al. survey. Combining these data with the density of bright LAEs in the Cosmic Evolution Survey and Subaru Deep Field provides the best constraints to date on the redshift 5.7 LAE luminosity function (LF). Schechter function parameters, {phi}* = 4.5 Multiplication-Sign 10{sup -4} Mpc{sup -3}, L* = 9.1 Multiplication-Sign 10{sup 42} erg s{sup -1}, and {alpha} = -1.70, are estimated using a maximum likelihood technique with a model for slit-losses. To place this result in the context of the UV-selected galaxy population, we investigate how various parameterizations of the Ly{alpha} equivalent width distribution, along with the measured UV-continuum LF, affect shape and normalization of the Ly{alpha} LF. The nominal model, which uses z {approx} 6 equivalent widths from the literature, falls short of the observed space density of LAEs at the bright end, possibly indicating a need for higher equivalent widths. This parameterization of the equivalent width distribution implies that as many as 50% of our faintest LAEs should have M{sub UV} > -18.0, rendering them undetectable in even the deepest Hubble Space Telescope surveys at this redshift. Hence, ultra-deep emission-line surveys find some of the faintest galaxies ever observed at the end of the reionization epoch. Such faint galaxies likely enrich the intergalactic medium with metals and maintain its ionized state in the post-reionization era. Observations of these objects provide a glimpse of the building blocks of present-day galaxies at an early time.

Henry, Alaina L.; Martin, Crystal L. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Dressler, Alan; McCarthy, Patrick [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sawicki, Marcin, E-mail: ahenry@physics.ucsb.edu [Department of Astronomy and Physics, Saint Mary's University, Halifax, NS B3H 3C3 (Canada)

2012-01-10

285

Al Comae, Not So Red Afterall; Photometry and Spectroscopy of a Very Faint TOAD.  

NASA Astrophysics Data System (ADS)

A red inter-loper has been detected in the vicinity of the faint Tremendous Outburst Amplitude Dwarf (TOAD) AL Comae, with a 3.95 arc-seconds separation between the center of both systems. New infrared photometry was taken with the 2.1m IRIM camera on the observation nights of July 11 and 12 of 1997. Analysis of this data shows that the previously published K band magnitude for AL Comae is not 15.8 but rather 17.9, with a V-K magnitude similar to that of G type star. We conclude that previous photometric analysis of AL Comae was contaminated by the close red dwarf. This suggests that the results from the optical spectral analysis by Howell et al. might have been contaminated as well. A new spectorscopic analysis in the optical range has been done on data taken with the 4m MMT on February 7, 1997. These new analysis agrees with our new photometric results. We re-analyzed the WHT data published in Howell et al. taking the red neighbor into acount, but the re-analysis seemed to be consistent with that of the published paper.

Galvan, F. J.; Garcia, M.; Callanan, P. J.

1999-12-01

286

The faint young sun-climate paradox - Continental influences  

NASA Astrophysics Data System (ADS)

We examine the various mechanisms which have been proposed to compensate for the climatic effects of a 30% increase in the solar luminosity over the past 4 1/2 billion years. Although atmospheric greenhouse effects have received most attention, other mechanisms may have played a role of comparable importance. In particular, we note that the development of continents during the past 2 1/2 billion years could have had a significant secular effect on the atmosphere-ocean heat transport system. As a result, past climates may have been less susceptible to complete freeze-over. A simple energy balance model is used to demonstrate the magnitude of this effect. Because the CO2 greenhouse effect is not the only means of compensating for solar evolution, the faint-young-sun problem should not be used to infer past levels of atmospheric CO2.

Endal, A. S.; Schatten, K. H.

1982-08-01

287

Explosive Nucleosynthesis in Luminous Hypernovae and Faint Supernovae  

NASA Astrophysics Data System (ADS)

The diversity in brightness and explosion energy of supernovae (SNe) that have recently been observed is remarkable. Determining the origin of unusual SNe, such as extremely faint or extremely luminous ones, or the very energetic explosions associated with GRBs (hypernovae), is very challenging. We present a core-collapse hypernova model for the extremely luminous Type Ic SN 2007bi as an alternative to the pair-instability model. We discuss how nucleosynthesis from a variety of SNe is connected to the abundance patterns of extremely metal-poor stars. Such connections may impose important constraints on the properties of the first stars, such as their evolution with mass accretion, or the asphericity of their explosions.

Nomoto, Ken'ichi; Moriya, Takashi; Tominaga, Nozomu; Suzuki, Tomoharu

2010-11-01

288

A faint extended cluster in the outskirts of NGC 5128: evidence of a low mass accretion  

NASA Astrophysics Data System (ADS)

We report the discovery of an extended globular cluster in a halo field in Centaurus A (NGC 5128), situated from the centre of that galaxy, imaged with the Advanced Camera for Surveys on board the Hubble Space Telescope. At the distance of the galaxy, the half-light radius of the cluster is rh ~ 17pc, placing it among the largest globular clusters known. The faint absolute magnitude of the star cluster, MV,? = -5.2, and its large size render this object somewhat different from the population of extended globular clusters previously reported, making it the first firm detection in the outskirts of a giant galaxy of an analogue of the faint, diffuse globular clusters present in the outer halo of the Milky Way. The colour-magnitude diagram of the cluster, covering approximately the brightest four magnitudes of the red giant branch, is consistent with an ancient, i.e. >~8Gyr, intermediate metallicity, i.e. [M/H] ~ -1.0dex, stellar population. We also report the detection of a second, even fainter cluster candidate which would have rh ~ 9pc and MV,? = -3.4 if it is at the distance of NGC 5128. The properties of the extended globular cluster and the diffuse stellar populations in its close vicinity suggest that they are part of a low mass accretion in the outer regions of NGC 5128. This work was based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. E-mail: mm@astro.livjm.ac.uk

Mouhcine, M.; Harris, W. E.; Ibata, R.; Rejkuba, M.

2010-05-01

289

Merged infrared catalogue  

NASA Technical Reports Server (NTRS)

A compilation of equatorial coordinates, spectral types, magnitudes, and fluxes from five catalogues of infrared observations is presented. This first edition of the Merged Infrared Catalogue contains 11,201 oservations from the Two-Micron Sky Survey, Observations of Infrared Radiation from Cool Stars, the Air Force Geophysics Laboratory four Color Infrared Sky Survey and its Supplemental Catalog, and from Catalog of 10 micron Celestial Objects (HALL). This compilation is a by-product of a computerized infrared data base under development at Goddard Space Flight Center; the objective is to maintain a complete and current record of all infrared observations from 1 micron m to 1000 micron m of nonsolar system objects. These observations are being placed into a standardized system.

Schmitz, M.; Brown, L. W.; Mead, J. M.; Nagy, T. A.

1978-01-01

290

Faint open clusters with 2MASS: BH 63, Lyngå 2, Lyngå 12 and King 20  

Microsoft Academic Search

Context: .Structural and dynamical parameters of faint open clusters are probed with quality 2MASS-photometry and analytical procedures developed for bright clusters. Aims: .We derive fundamental parameters of the faint open clusters Lyngå 2, BH 63, Lyngå 12 and King 20, the last three of which have no prior determinations. We also focus on the structure and dynamical state of these

E. Bica; C. Bonatto; R. Blumberg

2006-01-01

291

Near infrared imaging of the outer planets  

NASA Technical Reports Server (NTRS)

In the last year we have continued our program of near infrared imaging of the outer planets of the solar system. Uranus is virtually invisible at 2.3 microns, showing that the methane is an effective absorber of the incident sunlight and that there is very little aerosol content in the upper atmosphere. On the other hand, Neptune shows a haze present over the entire Northern Hemisphere at 2.3 microns. This leads to the inference that there is an aerosol layer at a high altitude. We have recovered the Neptune satellite, 1989 N1, which was first discovered in Voyager images. The satellite is exceedingly faint in the near infrared, and was detectable only because the planet itself was comparatively faint at this wavelength. Observations of this satellite, coupled with the Voyager images, permit us to substantially refine the satellite's orbit, and hence carefully probe the gravitational field of Neptune.

Matthews, K.; Soifer, B. T.

1991-01-01

292

Crystalline water ice on the Kuiper belt object (50000) Quaoar  

NASA Astrophysics Data System (ADS)

The Kuiper belt is a disk-like structure consisting of solid bodies orbiting the Sun beyond Neptune. It is the source of the short-period comets and the likely repository of the Solar System's most primitive materials. Surface temperatures in the belt are low (~ 50K), suggesting that ices trapped at formation should have been preserved over the age of the Solar System. Unfortunately, most Kuiper belt objects are too faint for meaningful compositional study, even with the largest available telescopes. Water ice has been reported in a handful of objects, but most appear spectrally featureless. Here we report near-infrared observations of the large Kuiper belt object (50000) Quaoar, which reveal the presence of crystalline water ice and ammonia hydrate. Crystallinity indicates that the ice has been heated to at least 110K. Both ammonia hydrate and crystalline water ice should be destroyed by energetic particle irradiation on a timescale of about 107yr. We conclude that Quaoar has been recently resurfaced, either by impact exposure of previously buried (shielded) ices or by cryovolcanic outgassing, or by a combination of these processes.

Jewitt, David C.; Luu, Jane

2004-12-01

293

Infrared objects near H2O masers in regions of active star formation. III - Evolutionary phases deduced from IR recombination line and other data  

NASA Astrophysics Data System (ADS)

Spectroscopic observations in the Br-alpha, Br-gamma, and Pf-gamma hydrogen-recombination lines of 11 compact objects near H2O masers, obtained during 1981 and 1982 using an InSb detector equipped with continuously variable filters on the 3.6-m telescope at ESO, are reported and analyzed. The derived correction factors are explained, and the continuum and recombination-line data are presented in tables and graphs and interpreted for each object. The objects G309.9+0.5, G328.3+0.43, G351.41+0.64, and G5.9-0.4 are found to be ultracompact H II regions (r at 10 microns less than or equal to 8 x 10 to the 16th cm), whereas G324.2+00.12 is a compact H II region, and the nature of the other objects remains unclear. A log-log plot IR luminosity versus (ne squared) (V) for a 25-object sample drawn from these data and from published data on other compact objects near H20 masers suggests that all of them are OB stars with incompletely developed ionization-bounded H II regions. A rough proportionality between H2O and integrated IR fluxes is demonstrated, and the evolutionary relationships implied are discussed.

Moorwood, A. F. M.; Salinari, P.

1983-09-01

294

Cosmic Infrared Background Fluctuations in Deep Spitzer Infrared Array Camera Images: Data Processing and Analysis  

NASA Astrophysics Data System (ADS)

This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale (gsim30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the ~1-5 ?m mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low (gsim1 nW m-2 sr-1 at 3-5 ?m), and thus consistent with current ?-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these source-subtracted CIB fluctuations, and to isolate the individual fluxes of these populations.

Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

2010-01-01

295

Radio loud far-infrared galaxies  

NASA Technical Reports Server (NTRS)

The first results are presented of a multiwavelength study of Infrared Astronomy Satellite (IRAS) galaxies with excess radio emission. The sample was selected by cross correlating the IRAS Faint Source Survey, and the Point Source Catalogue with the Texas radio survey. Recent optical (imaging and spectroscopic) and radio (VLA) observations are discussed. These observations will be used to investigate possible connections between radio galaxy activity, star formation and galaxy interactions.

Dey, Arjun; Vanbreugel, Wil; Shields, Joseph C.

1990-01-01

296

LOITA: Lunar Optical/Infrared Telescope Array  

NASA Technical Reports Server (NTRS)

LOITA (Lunar Optical/Infrared Telescope Array) is a lunar-based interferometer composed of 18 alt-azimuth telescopes arranged in a circular geometry. This geometry results in excellent uv coverage and allows baselines up to 5 km long. The angular resolution will be 25 micro-arcsec at 500 nm and the main spectral range of the array will be 200 to 1100 nm. For infrared planet detection, the spectral range may be extended to nearly 10 mu m. The telescope mirrors have a Cassegrain configuration using a 1.75 m diameter primary mirror and a 0.24 m diameter secondary mirror. A three-stage (coarse, intermediate, and fine) optical delay system, controlled by laser metrology, is used to equalize path lengths from different telescopes to within a few wavelengths. All instruments and the fine delay system are located within the instrument room. Upon exiting the fine delay system, all beams enter the beam combiner and are then directed to the various scientific instruments and detectors. The array instrumentation will consist of CCD detectors optimized for both the visible and infrared as well as specially designed cameras and spectrographs. For direct planet detection, a beam combiner employing achromatic nulling interferometry will be used to reduce star light (by several orders of magnitude) while passing the planet light. A single telescope will be capable of autonomous operation. This telescope will be equipped with four instruments: wide field and planetary camera, faint object camera, high resolution spectrograph, and faint object spectrograph. These instruments will be housed beneath the telescope. The array pointing and control system is designed to meet the fine pointing requirement of one micro-arcsec stability and to allow precise tracking of celestial objects for up to 12 days. During the lunar night, the optics and the detectors will be passively cooled to 70-80 K temperature. To maintain a continuous communication with the earth a relay satellite placed at the L4 libration point will be used in conjunction with the Advanced Tracking and Data Relay Satellite System (ATDRSS). Electrical power of about 10 kW will be supplied by a nuclear reactor based on the SP-100 technology. LOITA will be constructed in three phases of six telescopes each. The total mass of the first operational phase is estimated at 58,820 kg. The cost of the fully operational first phase of the observatory is estimated at $8.9 billion. LOITA's primary objectives will be to detect and characterize planets around nearby stars (up to ten parsec away), study physics of collapsed stellar objects, solar/stellar surface features and the processes in nuclear regions of galaxies and quasars. An interferometric array such as LOITA will be capable of achieving resolutions three orders of magnitude greater than Hubble's design goal. LOITA will also be able to maintain higher signal to noise ratios than are currently attainable due to long observation times available on the moon.

1993-01-01

297

Near-Infrared Camera and Multi-Object Spectrometer Observations of the Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry  

Microsoft Academic Search

This paper presents data obtained during the NICMOS Guaranteed Time Observations of a portion of the Hubble Deep Field. The data are in a catalog format similar to the publication of the original WFPC2 Hubble Deep Field program (Williams et al.). The catalog contains 342 objects in a 49.1\\

Rodger I. Thompson; Lisa J. Storrie-Lombardi; Ray J. Weymann; Marcia J. Rieke; Glenn Schneider; Elizabeth Stobie; Dyer Lytle

1999-01-01

298

THE PRIMEVAL POPULATIONS OF THE ULTRA-FAINT DWARF GALAXIES  

SciTech Connect

We present new constraints on the star formation histories of the ultra-faint dwarf (UFD) galaxies, using deep photometry obtained with the Hubble Space Telescope (HST). A galaxy class recently discovered in the Sloan Digital Sky Survey, the UFDs appear to be an extension of the classical dwarf spheroidals to low luminosities, offering a new front in efforts to understand the missing satellite problem. They are the least luminous, most dark-matter-dominated, and least chemically evolved galaxies known. Our HST survey of six UFDs seeks to determine if these galaxies are true fossils from the early universe. We present here the preliminary analysis of three UFD galaxies: Hercules, Leo IV, and Ursa Major I. Classical dwarf spheroidals of the Local Group exhibit extended star formation histories, but these three Milky Way satellites are at least as old as the ancient globular cluster M92, with no evidence for intermediate-age populations. Their ages also appear to be synchronized to within {approx}1 Gyr of each other, as might be expected if their star formation was truncated by a global event, such as reionization.

Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.; Avila, Roberto J.; Ferguson, Henry C., E-mail: tbrown@stsci.edu, E-mail: tumlinson@stsci.edu, E-mail: jkalirai@stsci.edu, E-mail: avila@stsci.edu, E-mail: ferguson@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

2012-07-01

299

Hot Young Solution to Faint Sun and Supernova Problems  

NASA Astrophysics Data System (ADS)

Results from three independent experiments involving the speed of light are presented. Luminosity of Type Ia supernovae depend upon constant fundamental parameters. Accurate measurements of c provide a valuable check on ``dark energy'' theories. One Theory states that scale R of Space/Time is related to age t by R = ct. Gravitation then requires that GM=tc^3. These expressions provide a simple solution to Einstein-Friedmann equations with k=0. Predicted change in c provides a close fit to observations of Type Ia supernova redshifts. The ``Faint Young Sun'' has been a paradox of astrophysics. According to standard models, when Earth was forming solar luminosity was only 75% of today's value. Geology and the fossil record contradict this prediction. Because the Sun turns fuel to energy according to E=mc^2, change in c precisely accounts for the difference. If c had not changed in the amounts predicted, life would not have evolved on Earth. The Lunar Laser Ranging Experiment from 1969 measures the Moon's recession at 3.82 cm/yr, anomalously high. Geological evidence states that average recession is only 2.9 cm/yr. Change in c precisely accounts for the anomaly, indicating that c changes to this day. Corroborating evidence from three truly independent experiments distinguishes Theory from other DE models. Since M = R = t (Planck Units) leads to predictions not epicycles, Theory should be considered as an alternative to more cumbersome ideas.

Riofrio, Louise

2008-04-01

300

No climate paradox under the faint early Sun.  

PubMed

Environmental niches in which life first emerged and later evolved on the Earth have undergone dramatic changes in response to evolving tectonic/geochemical cycles and to biologic interventions, as well as increases in the Sun's luminosity of about 25 to 30 per cent over the Earth's history. It has been inferred that the greenhouse effect of atmospheric CO(2) and/or CH(4) compensated for the lower solar luminosity and dictated an Archaean climate in which liquid water was stable in the hydrosphere. Here we demonstrate, however, that the mineralogy of Archaean sediments, particularly the ubiquitous presence of mixed-valence Fe(II-III) oxides (magnetite) in banded iron formations is inconsistent with such high concentrations of greenhouse gases and the metabolic constraints of extant methanogens. Prompted by this, and the absence of geologic evidence for very high greenhouse-gas concentrations, we hypothesize that a lower albedo on the Earth, owing to considerably less continental area and to the lack of biologically induced cloud condensation nuclei, made an important contribution to moderating surface temperature in the Archaean eon. Our model calculations suggest that the lower albedo of the early Earth provided environmental conditions above the freezing point of water, thus alleviating the need for extreme greenhouse-gas concentrations to satisfy the faint early Sun paradox. PMID:20360739

Rosing, Minik T; Bird, Dennis K; Sleep, Norman H; Bjerrum, Christian J

2010-04-01

301

No climate paradox under the faint early Sun  

NASA Astrophysics Data System (ADS)

Environmental niches in which life first emerged and later evolved on the Earth have undergone dramatic changes in response to evolving tectonic/geochemical cycles and to biologic interventions, as well as increases in the Sun's luminosity of about 25 to 30 per cent over the Earth's history. It has been inferred that the greenhouse effect of atmospheric CO2 and/or CH4 compensated for the lower solar luminosity and dictated an Archaean climate in which liquid water was stable in the hydrosphere. Here we demonstrate, however, that the mineralogy of Archaean sediments, particularly the ubiquitous presence of mixed-valence Fe(II-III) oxides (magnetite) in banded iron formations is inconsistent with such high concentrations of greenhouse gases and the metabolic constraints of extant methanogens. Prompted by this, and the absence of geologic evidence for very high greenhouse-gas concentrations, we hypothesize that a lower albedo on the Earth, owing to considerably less continental area and to the lack of biologically induced cloud condensation nuclei, made an important contribution to moderating surface temperature in the Archaean eon. Our model calculations suggest that the lower albedo of the early Earth provided environmental conditions above the freezing point of water, thus alleviating the need for extreme greenhouse-gas concentrations to satisfy the faint early Sun paradox.

Rosing, Minik T.; Bird, Dennis K.; Sleep, Norman H.; Bjerrum, Christian J.

2010-04-01

302

SUPERNOVA 2003ie WAS LIKELY A FAINT TYPE IIP EVENT  

SciTech Connect

We present new photometric observations of supernova (SN) 2003ie starting one month before discovery, obtained serendipitously while observing its host galaxy. With only a weak upper limit derived on the mass of its progenitor (<25 M{sub Sun }) from previous pre-explosion studies, this event could be a potential exception to the ''red supergiant (RSG) problem'' (the lack of high-mass RSGs exploding as Type IIP SNe). However, this is true only if SN2003ie was a Type IIP event, something which has never been determined. Using recently derived core-collapse SN light-curve templates, as well as by comparison to other known SNe, we find that SN2003ie was indeed a likely Type IIP event. However, with a plateau magnitude of {approx} - 15.5 mag, it is found to be a member of the faint Type IIP class. Previous members of this class have been shown to arise from relatively low-mass progenitors (<12 M{sub Sun }). It therefore seems unlikely that this SN had a massive RSG progenitor. The use of core-collapse SN light-curve templates is shown to be helpful in classifying SNe with sparse coverage. These templates are likely to become more robust as large homogeneous samples of core-collapse events are collected.

Arcavi, Iair; Gal-Yam, Avishay [Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Sergeev, Sergey G., E-mail: iair.arcavi@weizmann.ac.il [Crimean Astrophysical Observatory, P/O Nauchny, Crimea 98409 (Ukraine)

2013-04-15

303

Multivariate study of dynamically hot stellar systems: Clues to the origin of ultra compact and ultra faint dwarfs  

NASA Astrophysics Data System (ADS)

A multivariate classification has been performed for a large sample of dynamically hot stellar systems comprising globular clusters to giant ellipticals, in quest of the formation theory of ultra compact dwarf galaxies (UCDs). For this K means cluster analysis is carried out together with the optimum criterion (Sugar et al., 2003) with respect to three parameters, logarithm of stellar mass, logarithm of effective radius and stellar mass to light ratio. The present data set has been taken from Misgeld and Hilker (2011). We found five groups MK1-MK5. These are predominated by giant ellipticals (gEs), faint dwarf ellipticals (dEs), globular clusters (GCs), massive compact objects (UCDs and nuclei of dE,Ns) and bright dwarf ellipticals respectively. Almost all UCDs are found either in MK3 or MK4. The fraction is roughly 50%-50% between MK3 and MK4. Comparable fraction of UCDs share properties either with normal GCs or with nuclei of dE,N. This adds a quantitative constraint to the long discussed hypothesis that UCDs may be formed either as massive globular clusters or have an origin similar to nuclei of dwarf galaxies. We finally find that for our clustering test in mass-size-stellar M/L ratios, ultra faint dwarf galaxies are attributed to globular cluster group (MK3) and not to the dwarf galaxy group (MK2). This highlights that there is no clear cut morphological distinction between extended star clusters and ultra faint dwarfs. These groups are highly consistent with the groups found in a previous classification for a smaller sample and completely different set of parameters.

Chattopadhyay, Tanuka; Karmakar, Pradip

2013-08-01

304

The Location of the CO2, Fundamental in Clathrate Hydrates and its Application to Infrared Spectra of Icy Solar System Objects  

NASA Technical Reports Server (NTRS)

CO2 is present on the surface of many Solar System objects, but not always as a segregated, pure ice. In pure CO2-ice, the fundamental absorption is located near 4.268 micron (2343.3 wavenumbers). However, on several objects, the CO2 fundamental is shifted to higher frequency. This shift may be produced by CO2 gas trapped in another material, or adsorbed onto minerals. We have seen that a mixture of H2O, CH3OH4 and CO2 forms a type II clathrate when heated to 125 K and produces a CO2 fundamental near 4.26 micron. The exact location of the feature is strongly dependent on the initial ratio of the three components. We are currently exploring various starting ratios relevant to the Solar System to determine the minimum amount of CH3OH needed to convert all of the CO2 to the clathrate, i.e. eliminate the splitting of the CO2 fundamental. We are testing the stability of the clathrate to thermal processing and UV photolysis, and documenting the changes seen in the spectra in the wavelength range from 1-5 micron. We acknowledge financial support from the Origins of Solar Systems Program, the Planetary Geology and Geophysics and the NASA Postdoctoral Program.

Sandford, S. A.; Mastrapa, R. M. E.; Bernstein, M. P.; Cruikshank, D. P.

2006-01-01

305

High energy gamma-emission of faint solar flares  

NASA Astrophysics Data System (ADS)

Hard X-ray and gamma-ray emission in energy band E¿50 keV was first observed by AVS-F apparatus onboard CORONAS-F satellite (detector SONG-D) during some solar flares classes B and C by GOES classification. Such hard component registered in flares with duration less than 30 min. According to AVS-F data about 50High energy gamma-emission up to several tens of MeV was observed during some classes B and C flares, which temporal profiles were not corresponded to Neupert effect. For example, during class B2.3 limb solar flare January 7, 2005 maximum observed energy was Emax 36 MeV and during class B4.6 disk solar flare January 12, 2005 maximum observed energy was Emax 12 MeV. Properties of temporal profiles and energy spectra of faint solar flares, during which high energy gamma-emission were registered discussed in the presented work. There is not any strong correlation between presence or absence of hard X-ray and gamma-ray emission and the intensity of soft X-ray emission during solar flares. It was not observed any statistically significant count rate exceed above background level was during some class M flares, for example, during event November 8, 2001 (class M4.2, flare lasts from 14:59 UT up to 16:00 UT, maximum of soft X-ray emission was at 15:35 UT on GOES data).

Arkhangelskaja, Irene; Kotov, Yury; Glyanenko, Alexander; Arkhangelsky, Andrey; Kolchina, Mary; Kirichenko, Alexey

306

Infrared Fiber Optics.  

National Technical Information Service (NTIS)

This interim technical report summarizes the first year's research efforts to fabricate optical communications fibers that are transmissive between 1 and 12 micrometers. The ultimate objective of this program is to prepare infrared transmitting fibers wit...

J. A. Harrington R. Turk M. Henderson J. Myer

1979-01-01

307

SAX J1711.6-3808: a faint X-ray transient harboring a black hole?  

Microsoft Academic Search

Thanks to dedicated X-ray monitoring observations of the Galactic bulge with the Wide Field Cameras on BeppoSAX, several tens of faint X-ray transients have been discovered with peak fluxes that are just a few percent of that of classical X-ray novae. Most of these faint transients exhibit type-I X-ray bursts and, thus, harbor a neutron star. A few cases do

Jean in't Zand; Craig Markwardt; Maria Santos-Lleo; Angela Bazzano; Massimo Cocchi; Remon Cornelisse; John Heise; Erik Kuulkers; Lorenzo Natalucci; Celia Sanchez-Fernandez; Jean Swank; Pietro Ubertini

2002-01-01

308

The optical night sky at low surface brightness: High-latitude dust and faint field galaxies  

SciTech Connect

Deep CCD imaging in U, B{sub J}, R, and I, over angular scales ranging from a few arcseconds to over 30 arcminutes, is used to study two classes of astronomical objects that produce fluctuations in the dark night sky background: (1) interstellar dust clouds at high Galactic latitudes, initially identified by their thermal re-radiation of ambient starlight as IRAS 100 {mu}m cirrus; and (2) a population of faint blue field galaxies, which, at 30 B{sub J} mag arcsec{sup {minus}2}, begin to fill up the field of view. A CCD mosaicing technique, designed to allow imaging of large areas of the sky at low light levels, has been used to study the cirrus morphology. The scattering and re-emission of optical radiation from the cirrus are investigated, with the goal of learning more about the environment of these clouds and the physical processes involved. The cirrus is extremely red in both B{sub J}-R and R-I, much redder than a simple scattering model predicts. The excess R and I band flux is probably the result of luminescence in small hydrogenated dust grains. This very red color appears to be a universal signature of optically thin dust clouds at high latitudes, and should enable them to be distinguished from the second component, aggregates of faint blue galaxies. These galaxies dominate the number counts in the field, and the U band count slope is even steeper than that in B{sub J}. The colors, over the wavelength range 3,600 {angstrom}-1 {mu}m, are indicative of fairly recent evolution. The observed U-B{sub J} colors place an upper limit of z = 3 on the majority of these galaxies, unless they have an extremely (almost unreasonably) small Lyman break. A model for the evolution of field galaxies is developed, incorporating preferential brightening of present day dwarfs, and using the observed mass currently locked up as stars in a galaxy to constrain the galaxy's lifetime.

Guhathakurta, P.

1989-01-01

309

An Improved Technique for the Photometry and Astrometry of Faint Companions  

NASA Astrophysics Data System (ADS)

We propose a new approach to differential astrometry and photometry of faint companions in adaptive optics images. It is based on a prewhitening matched filter, also referred to in the literature as the Hotelling observer. We focus on cases where the signal of the companion is located within the bright halo of the parent star. Using real adaptive optics data from the 3 m Shane telescope at the Lick Observatory, we compare the performance of the Hotelling algorithm with other estimation algorithms currently used for the same problem. The real single-star data are used to generate artificial binary objects with a range of magnitude ratios. In most cases, the Hotelling observer gives significantly lower astrometric and photometric errors. In the case of high Strehl ratio (SR) data (SR?0.5), the differential photometry of a binary star with a ?m=4.5 and a separation of 0.6? is better than 0.1 mag; a factor of 2 lower than the other algorithms considered.

Burke, Daniel; Gladysz, Szymon; Roberts, Lewis; Devaney, Nicholas; Dainty, Chris

2009-07-01

310

Infrared Astronomy  

NSDL National Science Digital Library

This website from NASA's Infrared Astrophysics Data Center describes: the discovery of infrared waves; what infrared waves are and how they are used in astronomy; atmospheric windows; near, middle, and far infrared; the infrared universe; and infrared (IR) spectroscopy. It also provides an IR astronomy timeline; history and development of IR detector technology; information on projects, news and discoveries; an IR gallery; classroom activities; and links for getting involved in astronomy.

Hermans-Killam, Linda

311

Infrared Heaters  

NASA Technical Reports Server (NTRS)

The heating units shown in the accompanying photos are Panelbloc infrared heaters, energy savers which burn little fuel in relation to their effective heat output. Produced by Bettcher Manufacturing Corporation, Cleveland, Ohio, Panelblocs are applicable to industrial or other facilities which have ceilings more than 12 feet high, such as those pictured: at left the Bare Hills Tennis Club, Baltimore, Maryland and at right, CVA Lincoln- Mercury, Gaithersburg, Maryland. The heaters are mounted high above the floor and they radiate infrared energy downward. Panelblocs do not waste energy by warming the surrounding air. Instead, they beam invisible heat rays directly to objects which absorb the radiation- people, floors, machinery and other plant equipment. All these objects in turn re-radiate the energy to the air. A key element in the Panelbloc design is a coating applied to the aluminized steel outer surface of the heater. This coating must be corrosion resistant at high temperatures and it must have high "emissivity"-the ability of a surface to emit radiant energy. The Bettcher company formerly used a porcelain coating, but it caused a production problem. Bettcher did not have the capability to apply the material in its own plant, so the heaters had to be shipped out of state for porcelainizing, which entailed extra cost. Bettcher sought a coating which could meet the specifications yet be applied in its own facilities. The company asked The Knowledge Availability Systems Center, Pittsburgh, Pennsylvania, a NASA Industrial Applications Center (IAC), for a search of NASA's files

1979-01-01

312

Spitzer Ultra Faint SUrvey Program (SURFS UP). I. An Overview  

NASA Astrophysics Data System (ADS)

Spitzer UltRa Faint SUrvey Program is a joint Spitzer and Hubble Space Telescope Exploration Science program using 10 galaxy clusters as cosmic telescopes to study z >~ 7 galaxies at intrinsically lower luminosities, enabled by gravitational lensing, than blank field surveys of the same exposure time. Our main goal is to measure stellar masses and ages of these galaxies, which are the most likely sources of the ionizing photons that drive reionization. Accurate knowledge of the star formation density and star formation history at this epoch is necessary to determine whether these galaxies indeed reionized the universe. Determination of the stellar masses and ages requires measuring rest-frame optical light, which only Spitzer can probe for sources at z >~ 7, for a large enough sample of typical galaxies. Our program consists of 550 hr of Spitzer/IRAC imaging covering 10 galaxy clusters with very well-known mass distributions, making them extremely precise cosmic telescopes. We combine our data with archival observations to obtain mosaics with ~30 hr exposure time in both 3.6 ?m and 4.5 ?m in the central 4' × 4' field and ~15 hr in the flanking fields. This results in 3? sensitivity limits of ~26.6 and ~26.2 AB magnitudes for the central field in the IRAC 3.6 and 4.5 ?m bands, respectively. To illustrate the survey strategy and characteristics we introduce the sample, present the details of the data reduction and demonstrate that these data are sufficient for in-depth studies of z >~ 7 sources (using a z = 9.5 galaxy behind MACS J1149.5+2223 as an example). For the first cluster of the survey (the Bullet Cluster) we have released all high-level data mosaics and IRAC empirical point-spread function models. In the future we plan to release these data products for the entire survey. These observations are associated with programs Spitzer 90009, 60034, 00083, 50610, 03550, 40593, and Hubble Space Telescope GO10200, GO10863, GO11099, and GO11591. Furthermore based on ESO Large Program ID 181.A-0485.

Brada?, Maruša; Ryan, Russell; Casertano, Stefano; Huang, Kuang-Han; Lemaux, Brian C.; Schrabback, Tim; Gonzalez, Anthony H.; Allen, Steve; Cain, Benjamin; Gladders, Mike; Hall, Nicholas; Hildebrandt, Hendrik; Hinz, Joannah; von der Linden, Anja; Lubin, Lori; Treu, Tommaso; Zaritsky, Dennis

2014-04-01

313

The Development of Microshutters for the Near Infrared Spectrograph on the James Webb Space Telescope  

NASA Technical Reports Server (NTRS)

One of the James Webb Space Telescope's (JWST) primary science goals is to characterize the epoch of galaxy formation in the universe and observe the first galaxies and clusters of galaxies. This goal requires multi-band imaging and spectroscopic data in the near infrared portion of the spectrum for large numbers of very faint galaxies. Because such objects are sparse on the sky at the JWST resolution, a multi-object spectrograph is necessary to efficiently carry out the required observations. We have developed a fully programmable microshutter array that will be used as the field selector for the Near Infrared Spectrograph (NIRSpec) on JWST. This device allows slits to be opened at the locations of selected galaxies in the field of view while blocking other unwanted light from the sky background and bright sources. In practice, greater than 100 objects within the field of view will be observed simultaneously. In this paper, we describe the microshutter arrays, their development, fabrication, testing, and progress toward delivery of flight qualified devices to the NIRSpec instrument team in 2008.

Silverberg, Robert F.; Moseley, S.; Arendt, R. G.; Franz, D.; Jhabvala, M.; Kletetschka, G.; Kutyrev, A.; Li, M. J.; Rapchun, D.; Snodgrass, S.; Sohl, D.; Sparr, L.

2007-01-01

314

The high-velocity molecular flows near young stellar objects  

Microsoft Academic Search

The results of a search for high-velocity molecular gas associated with star forming molecular clouds are reported. Faint, high-velocity (DeltaV >= 30 km s-1)12CO emission is frequently found near buried infrared sources. In most clouds, the high-velocity gas is observed over an extended area having a typical radius around 1018 cm and exhibits bipolar structure with the redshifted emission formed

J. Bally; C. J. Lada

1983-01-01

315

Near-infrared (J, H, K) imaging of Herbig Ae/Be stars  

NASA Technical Reports Server (NTRS)

Near-infrared (J, H, K) images were obtained for 16 Herbig Ae/Be stars. The primary goal was to determine the contributions by circumstellar nebulae and nearby sources to near-infrared photometry carried out with large beams. Quasi-simultaneous photometric results were obtained with small apertures. The emission toward five Herbig Ae/Be stars is extended, including all four Group II sources in our sample (Hillebrand et al. 1992); 13 objects have nearby sources (within 10 sec separation). However, the extended emission and nearby sources are too faint to affect previous photometry significantly. The surface brightness profiles of most of the nebulae can be explained by reflection nebulae which scatter the light from the central star/disk systems with single, isotropic scattering processes. The exception is Par 21, which may require emission from very small grains. The color-color diagram, making use of our new photometry, essentially agrees with the results of Lada & Adams (1992). The Group II objects in our sample tend to have extended emission more frequently than do Group I objects, supporting the suggestion of Hillebrand et al. that Group II sources are more affected by circumstellar envelopes. However, most of the near-infrared emission comes from the central (less than or = 6 sec) regions. This upper limit is still much larger than the expected size of accretion disks. Possible envelope effects could not be ruled out for most Herbig Ae/Be stars with unresolved emission. The images do not clearly favor very small, thermally emitting grains as the origin of the near-infrared emission. The problem still exists of how to explain the observed peaks near 3 sec in the spectral energy distributions of Herbig Ae/Be stars. The possible effects of envelopes and companions are addressed.

Li, Wenbin; Evans, Neal J., II; Harvey, Paul M.; Colome, Cecilia

1994-01-01

316

MEASURING X-RAY VARIABILITY IN FAINT/SPARSELY SAMPLED ACTIVE GALACTIC NUCLEI  

SciTech Connect

We study the statistical properties of the normalized excess variance of variability process characterized by a ''red-noise'' power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an ''ensemble estimate'', based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

Allevato, V. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Paolillo, M. [Department of Physical Sciences, University Federico II, via Cinthia 6, I-80126 Naples (Italy); Papadakis, I. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion (Greece); Pinto, C. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA Utrecht (Netherlands)

2013-07-01

317

Measuring X-Ray Variability in Faint/Sparsely Sampled Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

We study the statistical properties of the normalized excess variance of variability process characterized by a "red-noise" power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an "ensemble estimate," based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

Allevato, V.; Paolillo, M.; Papadakis, I.; Pinto, C.

2013-07-01

318

Infrared Investigations.  

ERIC Educational Resources Information Center

Describes a series of simple and nontraditional experiments that enable students to discover the properties of infrared radiation by studying the propagation, reflection, diffusion, and refraction of infrared. The experiments rely on two modules, an infrared transmitter and an infrared receiver. (SAH)

Lascours, Jean; Albe, Virginie

2001-01-01

319

Infrared Studies of Low Mass Star Formation  

NASA Astrophysics Data System (ADS)

My thesis consists of seven infrared studies of low mass star formation. One chapter describes an all sky survey of young stars in the IRAS Point Source Catalog (IPSC). Three chapters contain studies of the Chamaeleon I star forming region. Two chapters concern star formation in the Chamaeleon II molecular cloud. Finally, one chapter deals with star formation in B209, which is a globule in the Taurus clouds. I will summarize the results of these studies in the above mentioned four categories. Advanced statistical classification methods have been used to extract a set of 5962 young stellar object candidates from the IPSC. In the selection procedure clustering properties on the sky were used in addition to the usually explored IRAS colours. A performance analysis indicates that in low mass star forming regions 87% of these objects are indeed young stars. All IRAS catalogues (IPSC, IRAS Serendipitous Survey Catalog and IRAS Faint Source Survey) have been searched for young stars born in the Chamaeleon I molecular cloud. These studies have led to the discovery of the exciting source of Herbig-Haro objects 49 and 50. Ground-based near-infrared photometry has been obtained for a majority of Chamaeleon I members in order to construct spectral energy distributions. Bolometric luminosities have been estimated for 62 out of the 81 known members to construct a luminosity function (LF). A comparison of the LF with that of the ? Ophiuchi infrared cluster suggests that star formation has evolved further in Chamaelon I. Young stars in the Chamaeleon II star forming region have been measured in the near infrared and IRAS data has been extracted in order to construct spectral energy distributions and luminosity estimates. An additional search based on the IRAS data has been performed to find new young stellar object candidates. The spatial distribution of young stars and candidate members shows that star formation is more widespread in Chamaelon II than in the well-studied Chamaeleon I. A study of star formation in B209 revealed two new embedded sources belonging to the group of young stars born in the Taurus region. This result from a small area of the whole cloud complex suggests that our current sample of embedded objects in Taurus may be severely incomplete. One of the new objects is of sub-solar luminosity, but yet it drives a relatively strong molecular outflow. It is possible that the known sample of luminous embedded sources exciting molecular outflows has a large number of low luminosity counterparts, which are extremely difficult to discover. The embedded sources may thus have a similar kind of luminosity function as the T Tauri stars making them physically more similar to pre-main-sequence stars than to protostars. (If interested in a personal copy of my thesis, please, contact the above mentioned E-mail address.)

Prusti, Timo

1992-01-01

320

Near-infrared images of MG 1131+0456 with the W. M. Keck telescope: Another dusty gravitational lens?  

NASA Technical Reports Server (NTRS)

Images of the gravitational lens system MG 1131+0456 taken with the near-infrared camera on the W. M. Keck telescope in the J and K(sub s) bands show that the infrared counterparts of the compact radio structure are exceedingly red, with J - K greater than 4.2 mag. The J image reveals only the lensing galaxy, while the K(sub s) image shows both the lens and the infrared counterparts of the compact radio components. After subtracting the lensing galaxy from the K(sub s) image, the position and orientation of the compact components agree with their radio counterparts. The broad-band spectrum and observed brightness of the lens suggest a giant galaxy at a redshift of approximately 0.75, while the color of the quasar images suggests significant extinction by dust in the lens. There is a significant excess of faint objects within 20 sec of MG 1131+0456. Depending on their mass and redshifts, these objects could complicate the lensing potential considerably.

Larkin, J. E.; Matthews, K.; Lawrence, C. R.; Graham, J. R.; Harrison, W.; Jernigan, G.; Lin, S.; Nelson, J.; Neugebauer, G.; Smith, G.

1994-01-01

321

YSO studies with infrared interferometers  

NASA Technical Reports Server (NTRS)

The observational technique of long baseline infrared interferometry provides a unique opportunity for studying the small scale structure of young stellar objects, particularly circumstellar disks and multiplicity. The technique of infrared interferometry is briefly described and observations of young stellar objects are reviewed.

Akeson, R.

2001-01-01

322

Gemini/GMOS Spectroscopy of Faint z=6 Ly-alpha Line Emitters in The Hubble Ultra Deep Field  

NASA Astrophysics Data System (ADS)

Redshift 6, one billion years after the Big Bang, marks the end of the reionization epoch. A crucial question is whether the UV flux from young starbursts at this redshift is sufficient to achieve this reionzation. We have used the Lyman break technique to identify candidate star-forming galaxies at this redshift in deep HST/ACS images. Using the Hubble Ultra Deep Field, we identified i-band drop-outs as faint as z(AB)=28.5mag, corresponding to unobscured star-formation rates of 1Msun/yr at z 6. Spectroscopic confirmation of this population is crucial, to guard against low-redshift interlopers (Extremely Red Objects at z 1-2 and low-mass Galactic stars) and to study the Lyman-alpha emission line properties of z 6 galaxies. We have undertaken the deepest spectroscopy yet to achieve this. The Gemini Lyman-Alpha at Reionisation Era project (GLARE) has obtained 36 hours of spectroscopy on a single GMOS slitmask from Gemini-South, with a spectral resolution of lambda/Delta(lambda) 1000. This resolving power is sufficient to see the characteristic asymmetric Lyman-alpha profile, and reject the [OII] emission line doublet from lower redshift sources. We have secured spectroscopic redshifts for the some of the faintest continuum-selected objects yet, and place tight constraints on the equivalent width of Lyman-alpha emission for much of our i-drop sample. We find that the fraction of galaxies with little or no emission is similar to that at z 3, but that the z 6 population has a tail of sources with high rest frame equivalent widths. Possible explanations for this effect include a tendency towards stronger line emission in faint sources, which may arise from extreme youth or low metallicity in the Lyman-break population at high redshift, or possibly a top-heavy initial mass function.

Bunker, Andrew J.; Stanway, E. R.; Glazebrook, K.; Abraham, R. G.; Rhoads, J.; Malhotra, S.; Crampton, D.; Colless, M.; Chiu, K.; GLARE project (Gemini Lyman-Alpha at Reionzation Era)

2007-07-01

323

The search for faint radio supernova remnants in the outer Galaxy: five new discoveries  

NASA Astrophysics Data System (ADS)

Context. High resolution and sensitivity large-scale radio surveys of the Milky Way are critical in the discovery of very low surface brightness supernova remnants (SNRs), which may constitute a significant portion of the Galactic SNRs still unaccounted for (ostensibly the "missing SNR problem"). Aims: The overall purpose here is to present the results of a systematic, deep data-mining of the Canadian Galactic plane Survey (CGPS) for faint, extended non-thermal and polarized emission structures that are likely the shells of uncatalogued SNRs. Methods: We examine 5 × 5 degree mosaics from the entire 1420 MHz continuum and polarization dataset of the CGPS after removing unresolved "point" sources and subsequently smoothing them. Newly revealed extended emission objects are compared to similarly prepared CGPS 408 MHz continuum mosaics, as well as to source-removed mosaics from various existing radio surveys at 4.8 GHz, 2.7 GHz, and 327 MHz, to identify candidates with non-thermal emission characteristics. We integrate flux densities at each frequency to characterise the radio spectra behaviour of these candidates. We further look for mid- and high-frequency (1420 MHz, 4.8 GHz) ordered polarized emission from the limb brightened "shell"-like continuum features that the candidates sport. Finally, we use IR and optical maps to provide additional backing evidence. Results: Here we present evidence that five new objects, identified as filling all or some of the criteria above, are strong candidates for new SNRs. These five are designated by their Galactic coordinate names G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8, and G160.1-1.1. The radio spectrum of each is presented, highlighting their steepness, which is characteristic of synchrotron radiation. CGPS 1420 MHz polarization data and 4.8 GHz polarization data also provide evidence that these objects are newly discovered SNRs. These discoveries represent a significant increase in the number of SNRs known in the outer Galaxy second quadrant of longitude (90° < ? < 180°), and suggests that deep mining of other current and future Milky Way surveys will find even more objects and help to reconcile the difference between expected numbers of Galactic SNRs and the smaller number of currently known SNRs.

Gerbrandt, Stephanie; Foster, Tyler J.; Kothes, Roland; Geisbüsch, Jörn; Tung, Albert

2014-06-01

324

The Faint-End of the Galaxy Luminosity Function in the Hydra I Cluster  

NASA Astrophysics Data System (ADS)

INTRODUCTION: Dwarf galaxies account for a large share of cluster galaxies and their properties should be closely related to the formation and evolution of clusters. Despite the obvious importance, however, the number of very faint (down to M ˜ -10) cluster samples available to date is limited and properties of such faint galaxies remain unclear. In this study, we aim to reveal very faint-end slopes of galaxy luminosity functions (LFs) in the Hydra I cluster (Abell 1060) at z = 0.0126, in which such very faint galaxies have not been probed yet. OBSERVATIONS: We base our analyses on the data taken with the Suprime-Cam on the Subaru telescope at Mauna Kea. A deep photometric survey was carried out in the B- and Rc-bands. We observed the central region as well as a peripheral region of Hydra I. This is because we aim to investigate the environmental dependence of properties of very faint galaxies. We subtract fore-/background galaxy contamination in the cluster fields and obtain intrinsic LFs of the cluster galaxies. RESULTS AND DISCUSSION: We find that the LFs at the fainter magnitudes have a slightly steeper slope than that reported on the same cluster previously. The slope is flatter at faint magnitudes (M > -14) than that at the brighter magnitudes. This tendency is consistent with a composite LF constructed from several nearby clusters by previous work. Although the LFs in the Hydra central region are similar to those in the peripheral region at M < -14, the LF slope in the peripheral region is slightly flatter than that in the central region in the fainter magnitude range. This means that a larger number of dwarf galaxies reside in denser environments. This tend is seen only in the red galaxy LFs when we separate the Hydra member galaxies into red and blue galaxies. The Hydra I cluster is dominated by red galaxies down to M ˜ -10.

Yamanoi, H.; Tanaka, M.

2007-05-01

325

An Infrared Survey of Herbig-Haro Energy Sources  

NASA Astrophysics Data System (ADS)

Herbig-Haro (HH) flows are thought to be an extremely important part of the star formation process. They are the result of high-velocity outflows emanating from young accreting stars. They are seen at optical wavelengths as nebulous knots of shock-excited line emission resulting from the impact of ejected gas on either ambient molecular cloud material or gas/dust released in previous outburst events. HH flows appear episodic in nature and are postulated to occur throughout a stars’ early formation history. The stars responsible for HH flows, which have been designated Herbig-Haro energy sources (HHens), are often embedded in dense circumstellar envelopes and disks and/or located deep within molecular clouds making them optically faint and hence, less well-studied than their optical counterparts. Some HHens are optically visible and yet have still been studied sparingly. Several outstanding questions remain as to the nature of HHens and the processes leading to the ejection of HH flows. We present the results of an infrared survey of 66 HHens in an effort to provide more reliable data on these objects. Photometric analysis of the HHens was made from data taken with IRAC and MIPS cameras onboard the Spitzer Space Telescope. We present all available infrared photometry along with colors. Using this we will classify these young objects using color-color diagrams based on data from Allen et al. (2004) and Muzerolle et al. (2007). This work was conducted by a Research Experience for Undergraduates (REU) position at the University of Hawai'i's Institute for Astronomy and funded by the NSF.

Battisti, Andrew; Aspin, C.

2010-01-01

326

FIRST-2MASS Red Quasars: Transitional Objects Emerging from the Dust  

NASA Astrophysics Data System (ADS)

We present a sample of 120 dust-reddened quasars identified by matching radio sources detected at 1.4 GHz in the Faint Images of the Radio Sky at Twenty Centimeters survey with the near-infrared Two Micron All Sky Survey catalog and color-selecting red sources. Optical and/or near-infrared spectroscopy provide broad wavelength sampling of their spectral energy distributions that we use to determine their reddening, characterized by E(B - V). We demonstrate that the reddening in these quasars is best described by Small-Magellanic-Cloud-like dust. This sample spans a wide range in redshift and reddening (0.1 <~ z <~ 3, 0.1 <~ E(B - V) <~ 1.5), which we use to investigate the possible correlation of luminosity with reddening. At every redshift, dust-reddened quasars are intrinsically the most luminous quasars. We interpret this result in the context of merger-driven quasar/galaxy co-evolution where these reddened quasars are revealing an emergent phase during which the heavily obscured quasar is shedding its cocoon of dust prior to becoming a "normal" blue quasar. When correcting for extinction, we find that, depending on how the parent population is defined, these red quasars make up <~ 15%-20% of the luminous quasar population. We estimate, based on the fraction of objects in this phase, that its duration is 15%-20% as long as the unobscured, blue quasar phase.

Glikman, Eilat; Urrutia, Tanya; Lacy, Mark; Djorgovski, S. George; Mahabal, Ashish; Myers, Adam D.; Ross, Nicholas P.; Petitjean, Patrick; Ge, Jian; Schneider, Donald P.; York, Donald G.

2012-09-01

327

FIRST-2MASS RED QUASARS: TRANSITIONAL OBJECTS EMERGING FROM THE DUST  

SciTech Connect

We present a sample of 120 dust-reddened quasars identified by matching radio sources detected at 1.4 GHz in the Faint Images of the Radio Sky at Twenty Centimeters survey with the near-infrared Two Micron All Sky Survey catalog and color-selecting red sources. Optical and/or near-infrared spectroscopy provide broad wavelength sampling of their spectral energy distributions that we use to determine their reddening, characterized by E(B - V). We demonstrate that the reddening in these quasars is best described by Small-Magellanic-Cloud-like dust. This sample spans a wide range in redshift and reddening (0.1 {approx}< z {approx}< 3, 0.1 {approx}< E(B - V) {approx}< 1.5), which we use to investigate the possible correlation of luminosity with reddening. At every redshift, dust-reddened quasars are intrinsically the most luminous quasars. We interpret this result in the context of merger-driven quasar/galaxy co-evolution where these reddened quasars are revealing an emergent phase during which the heavily obscured quasar is shedding its cocoon of dust prior to becoming a 'normal' blue quasar. When correcting for extinction, we find that, depending on how the parent population is defined, these red quasars make up {approx}< 15%-20% of the luminous quasar population. We estimate, based on the fraction of objects in this phase, that its duration is 15%-20% as long as the unobscured, blue quasar phase.

Glikman, Eilat [Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); Urrutia, Tanya [Leibniz Institut fuer Astrophysik, An der Sternwarte 16, D-14482 Potsdam (Germany); Lacy, Mark [National Radio Astronomy Observatory, Charlottesville, VA (United States); Djorgovski, S. George; Mahabal, Ashish [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Petitjean, Patrick [Institut d'Astrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis bd Arago, F-75014 Paris (France); Ge, Jian [Astronomy Department, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G., E-mail: eilat.glikman@yale.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

2012-09-20

328

Change in center-limb profiles of faint Fraunhofer lines, 1  

NASA Technical Reports Server (NTRS)

The precise photoelectric center-to-limb observations of the ten very faint lines (d sub O 10%) were made, using a double-pass spectrograph. The profiles of more intensive (d sub O 10%) were made, using a double-pass spectrograph. The profiles of more intensive lines (35 d sub O 10%) undergo a center-to-limb change from the V-shaped form with very faint wings to the U-shaped one without appreciable wings. The equivalent width changes differently and in general satisfies no simplified photospheric scheme.

Gurtovenko, E. A.; Kondrashova, N. N.

1973-01-01

329

TV Observation of the Leonid Meteor Shower in 2002: First Observation of a Faint Meteor Storm  

NASA Astrophysics Data System (ADS)

TV observations of the Leonid meteor shower were carried out between 18h (UT) and 20.h5 (UT) on 2002 November17. In total, 412 Leonid meteors were observed along with 303 non-Leonid meteors. Enhanced activity of faint (mag < +10) Leonid meteors was observed between 19.h5 (UT) and 20.h5 (UT), with a peak influx of 1.8 × 10-4 km-2 s-1. The activity of this peak was rich in faint meteors, without visible meteors, which was different from the storm observed in 2001 over Japan. Comparisons between the observed peak and several theoretical predictions are discussed.

Fujiwara, Yasunori; Ueda, Masayoshi; Kawasaki, Yasuhiro; Nakamura, Takuji

2003-12-01

330

Star Formation as Seen by the Infrared Array Camera on Spitzer.  

National Technical Information Service (NTIS)

The Infrared Array Camera (IRAC) onboard Spitzer has imaged regions of star formation (SF) in its four IR bands with spatial resolutions of approx. 2 inches/pixel. IRAC is sensitive enough to detect very faint, embedded young stars at levels of tens of Jy...

H. A. Smith L. Allen T. Megeath P. BArmby N. Calvet

2005-01-01

331

Swallowed Object  

MedlinePLUS

... toys, coins, safety pins, buttons, bones, wood, glass, magnets, batteries or other foreign objects. Problems may arise ... toys, coins, safety pins, buttons, bones, wood, glass, magnets, batteries or other foreign objects. These objects often ...

332

Discoveries from a Near-infrared Proper Motion Survey Using Multi-epoch Two Micron All-Sky Survey Data  

NASA Astrophysics Data System (ADS)

We have conducted a 4030 deg2 near-infrared proper motion survey using multi-epoch data from the Two Micron All-Sky Survey (2MASS). We find 2778 proper motion candidates, 647 of which are not listed in SIMBAD. After comparison to Digitized Sky Survey images, we find that 107 of our proper motion candidates lack counterparts at B, R, and I bands and are thus 2MASS-only detections. We present results of spectroscopic follow-up of 188 targets that include the infrared-only sources along with selected optical-counterpart sources with faint reduced proper motions or interesting colors. We also establish a set of near-infrared spectroscopic standards with which to anchor near-infrared classifications for our objects. Among the discoveries are six young field brown dwarfs, five "red L" dwarfs, three L-type subdwarfs, twelve M-type subdwarfs, eight "blue L" dwarfs, and several T dwarfs. We further refine the definitions of these exotic classes to aid future identification of similar objects. We examine their kinematics and find that both the "blue L" and "red L" dwarfs appear to be drawn from a relatively old population. This survey provides a glimpse of the kinds of research that will be possible through time-domain infrared projects such as the UKIDSS Large Area Survey, various VISTA surveys, and WISE, and also through z- or y-band enabled, multi-epoch surveys such as Pan-STARRS and LSST. Some of the spectroscopic 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. Other spectroscopic data were collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Kirkpatrick, J. Davy; Looper, Dagny L.; Burgasser, Adam J.; Schurr, Steven D.; Cutri, Roc M.; Cushing, Michael C.; Cruz, Kelle L.; Sweet, Anne C.; Knapp, Gillian R.; Barman, Travis S.; Bochanski, John J.; Roellig, Thomas L.; McLean, Ian S.; McGovern, Mark R.; Rice, Emily L.

2010-09-01

333

Preliminary analysis on faint luminous lightning events recorded by multiple high speed cameras  

NASA Astrophysics Data System (ADS)

The objective of this work is the study of some faint luminous events produced by lightning flashes that were recorded simultaneously by multiple high-speed cameras during the previous RAMMER (Automated Multi-camera Network for Monitoring and Study of Lightning) campaigns. The RAMMER network is composed by three fixed cameras and one mobile color camera separated by, in average, distances of 13 kilometers. They were located in the Paraiba Valley (in the cities of São José dos Campos and Caçapava), SP, Brazil, arranged in a quadrilateral shape, centered in São José dos Campos region. This configuration allowed RAMMER to see a thunderstorm from different angles, registering the same lightning flashes simultaneously by multiple cameras. Each RAMMER sensor is composed by a triggering system and a Phantom high-speed camera version 9.1, which is set to operate at a frame rate of 2,500 frames per second with a lens Nikkor (model AF-S DX 18-55 mm 1:3.5 - 5.6 G in the stationary sensors, and a lens model AF-S ED 24 mm - 1:1.4 in the mobile sensor). All videos were GPS (Global Positioning System) time stamped. For this work we used a data set collected in four RAMMER manual operation days in the campaign of 2012 and 2013. On Feb. 18th the data set is composed by 15 flashes recorded by two cameras and 4 flashes recorded by three cameras. On Feb. 19th a total of 5 flashes was registered by two cameras and 1 flash registered by three cameras. On Feb. 22th we obtained 4 flashes registered by two cameras. Finally, in March 6th two cameras recorded 2 flashes. The analysis in this study proposes an evaluation methodology for faint luminous lightning events, such as continuing current. Problems in the temporal measurement of the continuing current can generate some imprecisions during the optical analysis, therefore this work aim to evaluate the effects of distance in this parameter with this preliminary data set. In the cases that include the color camera we analyzed the RGB mode (red, green, blue) and compared them with the data provided by the black and white cameras for the same event and the influence of these parameters with the luminosity intensity of the flashes. Two peculiar cases presented, from the data obtained at one site, a stroke, some continuing current during the interval between the strokes and, then, a subsequent stroke; however, the other site showed that the subsequent stroke was in fact an M-component, since the continuing current had not vanished after its parent stroke. These events generated a dubious classification for the same event that was based only in a visual analysis with high-speed cameras and they were analyzed in this work.

Alves, J.; Saraiva, A. V.; Pinto, O.; Campos, L. Z.; Antunes, L.; Luz, E. S.; Medeiros, C.; Buzato, T. S.

2013-12-01

334

Infrared knots along protostellar jets (Giannini+, 2004)  

NASA Astrophysics Data System (ADS)

We present the near infrared spectra (0.9-2.5 micron) of protostellar jets (HH 24-26, HH72, BHR71). The observations were carried out with Sofi at R~600 with the 1x290arcsec slit. The spectra are dominated by H2 rovibrational lines (v up 5). Faint emission from ionized material in form of [FeII] and [SII] lines is also recognizable. The tables contain the observed lines together with the measured flux. The reported error derives from the rms of the baseline, multiplied by the width of the instrumental profile (30 Angstrom). (4 data files).

Giannini, T.; McCoey, C.; Caratti o Garatti, A.; Nisini, B.; Lorenzetti, D.; Flower, D.

2004-01-01

335

New faint planetary nebulae from the DSS and SDSS  

NASA Astrophysics Data System (ADS)

Having surveyed ~ 10% of the sky, we have identified more than 130 PN candidates by surveying multicolour Digitized Sky Survey (DSS), Sloan Digitized Sky Survey (SDSS), and combined [O III], H? and [S II] images. In a first imaging and spectroscopy campaign, 51 objects were identified as true and probable PNe. This work presents an additional 17 probable or possible PNe identified since that study. The majority of these candidates are situated at Galactic latitudes |b| > 5^, with the exception of seven objects located closer to the Galactic plane. Using the techniques described here that do not require any new survey data, we anticipate that many more PNe are waiting to be found, perhaps as many as 90.

Kronberger, Matthias; Jacoby, George H.; Ciardullo, Robin; Crisp, Richard D.; De Marco, Orsola; Douchin, Dimitri; Frew, David J.; Harmer, Dianne; Howell, Mike; Howell, Steve B.; Parker, Quentin A.; Patchick, Dana; Rector, Travis; Riddle, Dave; Teutsch, Philipp

2012-08-01

336

Cosmic Infrared Background Fluctuations in Deep Spitzer Infrared Array Camera Images: Data Processing and Analysis  

NASA Technical Reports Server (NTRS)

This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale ([greater, similar]30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the [approx]1-5 [mu]m mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low ([greater, similar]1 nW m-2 sr-1 at 3-5 [mu]m), and thus consistent with current [gamma]-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these source-subtracted CIB fluctuations, and to isolate the individual fluxes of these populations.

Arendt, Richard; Kashlinsky, A.; Moseley, S.; Mather, J.

2010-01-01

337

Infrared thermography  

SciTech Connect

Infrared thermography is a useful tool for the diagnosis of problems in building systems. In instances where a building owner has several large buildings, an investment in a typical $30,000 infrared system may be cost effective. In most instances, however, the rental of an infrared system or the hiring of an infrared consulting service is a cost effective alternative. As can be seen from the several applications presented here, any mechanical problem manifesting itself in an atypical temperature pattern can usually be detected. The two primary savings generated from infrared analysis of building systems are maintenance and energy.

Roberts, C.C. Jr.

1982-12-01

338

View of southeast side, faint "141" sign, Cranes P76 and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of southeast side, faint "141" sign, Cranes P-76 and P-71 are behind, view facing northwest - U.S. Naval Base, Pearl Harbor, Dry Dock No. 1, Latrine, Sixth Street, adjacent to Dry Dock No. 1, Pearl City, Honolulu County, HI

339

GM=tc^3 Space\\/Time, Supernovae and the Faint Young Sun  

Microsoft Academic Search

The Faint Young Sun has long been a paradox of astrophysics. The Standard Solar Model predicts that when Earth was formed solar luminosity was approximately 70% of its present value. Earth temperature would have been 15K below freezing point, making evolution of life unlikely. Geology and the fossil record contradict this prediction. Surveys of Type Ia supernovae indicate that redshifts

Louise Riofrio

2006-01-01

340

Studies of Selected Voids. Faint Galaxies in the Direction of the Void 0049 +05  

Microsoft Academic Search

Coordinates, multiaperture apparent B-magnitudes, diameters, position angles and some morphological parameters have been defined for 992 faint galax- ies from total 2251 galaxies in the region of 1 sq. deg. in the direction of 0049+05 void. The data have been taken with the 2-m RCC telescope of the NAO \\

G. T. Petrov; L. Slavcheva-Mihova; V. Kopchev

341

Future possibilities for lunar occultation studies of faint X-ray sources  

Microsoft Academic Search

Lunar occultation can be considered of interest for future missions dedicated to X-ray astronomy only if instruments with a large enough collecting area are used. In this case, observations of the numerous, faint X-ray sources occulted by the moon during a typical satellite lifetime of several years, can, in principle, add good source positioning as a free bonus to a

Sandro Mereghetti; Giovanni F. Bignami; Clyde Zaidins

1990-01-01

342

The early faint sun paradox: Organic shielding of ultraviolet-labile greenhouse gases  

Microsoft Academic Search

Atmospheric mixing ratios of â¼10{sup -5 {+-}1} for ammonia on the early Earth would have been sufficient, through the resulting greenhouse warming, to counteract the temperature effects of the faint early sun. One argument against such model atmospheres has been the short time scale for ammonia photodissociation by solar ultraviolet light. Here it is shown that ultraviolet absorption by steady-state

C. Sagan; C. Chyba

1997-01-01

343

Microscope objectives.  

PubMed

The objective is the most crucial image-forming component of a microscope. A knowledge of the many types of objectives available and their characteristics is critical to the selection of appropriate objectives for image cytometry. This unit discusses aberrations in image formation and their correction, construction, and types of objectives, and objectives for other microscopy applications, explaining the advantages and limitations of each one. PMID:21965106

LoBiondo, Joseph; Abramowitz, Mortimer; Friedman, Marc M

2011-10-01

344

A Search for Faint Planetary Nebulae Using the DSS  

NASA Astrophysics Data System (ADS)

A group of amateur astronomers (Deep Sky Hunters) has identified ˜50 candidate PNe by visually searching the 1st and 2nd generation red Digital Sky Survey images. Candidate PNe are then observed in H? with larger telescopes, primarily the WIYN 3.5-m on Kitt Peak, and the 1.2-m and 1.5-m at Haute-Provence Observatory (OHP). Thus far, ˜20 new PNe have been found. These objects have a strong tendency to have low surface brightness and to be relatively round.

Jacoby, G. H.; Kronberger, M.; Patchick, D.; Teutsch, P.; Saloranta, J.; Acker, A.; Frew, D.

2007-06-01

345

Exploring Infrared Image Technology  

NSDL National Science Digital Library

In this introductory activity, learners investigate and discuss infrared images of various everyday objects, such as toasters, hairdryers, and running water, to learn about infrared imaging. Student questions about the false-color images help guide a discussion about what they are, how they are different from visible light images, and the information that such images contain. Observation, comparing and contrasting, and reasoning skills are emphasized. The accompanying website features background information for the teacher, pre-requisite skills and knowledge for the student, multiple image sets, assessment information, student worksheets, extension and transfer activities, and additional resources. This is an introductory activity for both the Infrared Zoo and Infrared Yellowstone lessons available on the Cool Cosmos website.

346

Ultraluminous infrared galaxies  

NASA Technical Reports Server (NTRS)

One of the major discoveries of the the IRAS all-sky survey was a population of sources having the bolometric luminosities of quasars, but where more than 90 percent of the luminosity emerges in the infrared. These objects, more numerous than quasars, are found exclusivly in interacting/merging galaxies that are extremely rich in interstellar gas. We have accumulated evidence that suggests that these systems are indeed quasars, obscured by many tens of magnitudes of extinction. We suggest that these Ultraluminous Infrared Galaxies are the formation stage of quasars, and that colliding galaxies, ultraluminous infrared galaxies, and quasars might be linked through an evolutionary sequence where the infrared bright phase is one in which the quasar is formed in the nucleus of a merger system, and is enshrouded in gas and dust, while the UV excess quasars are at the end state of quasar evolution where most of the enveloping dust cloud has been dissipated, and the quasar is visible directly.

Soifer, B. T.

1991-01-01

347

Infrared radiant heating  

SciTech Connect

Retrofitting convective forced air heating systems with infrared (IR) systems can save as much as 50 percent of the total heating bill. Infrared heating is more efficient for two reasons: it can be directed to heat only occupied space; and it does not heat the air in a space, it only heats people and objects. Infrared heating works best where convective heaters are not practical. Large open bay buildings, such as hangars, workshops, and warehouses, with large volumes of air to be heated and plenty of unoccupied space are good candidates for retrofit. This TechData Sheet will help activity personnel understand infrared radiant heating, and identify opportunities for energy-conserving retrofit projects.

Cannon, S.; Rocha, M.

1996-05-01

348

Ultraluminous Infrared Galaxies: Atlas of Near-Infrared Images  

Microsoft Academic Search

A sample of 27 ultraluminous infrared galaxy (ULIRG) systems has been imaged at 1.6 mum using the Hubble Space Telescope (HST) Near Infrared Camera and Multi-Object Spectrometer (NICMOS). These ULIRGs are from a larger sample also imaged with HST in the I band. Images and catalog information for the NICMOS subsample, as well as brief morphological descriptions of each system

H. A. Bushouse; K. D. Borne; L. Colina; R. A. Lucas; M. Rowan-Robinson; A. C. Baker; D. L. Clements; A. Lawrence; S. Oliver

2002-01-01

349

Discovery of the candidate Kuiper belt object 1992 QB1  

NASA Astrophysics Data System (ADS)

The discovery of a new faint object in the outer solar system, 1992 QB1, moving beyond the orbit of Neptune is reported. It is suggested that the 1992 QB1 may represent the first detection of a member of the Kuiper belt (Edgworth, 1949; Kuiper, 1951), the hypothesized population of objects beyond Neptune and a possible source of the short-period comets, as suggested by Whipple (1964), Fernandez (1980), and Duncan et al. (1988).

Jewitt, D.; Luu, J.

1993-04-01

350

CCD time-resolved photometry of faint cataclysmic variables. II  

SciTech Connect

Time-resolved optical broad-band light curves obtained from differential photometry on sequential CCD frames of the known or suspected cataclysmic variable FO And, EH Aqr, WX Cet, XX Cet, AL Com, V503 Cyg, AH Eri, CP Eri, IR Gem, RW UMi, PG0134+070, and US 3215 are presented. The analysis of the light curves with coverage of greater than 2 hrs shows repeatable periodicity in five objects. PG0134+070 exhibits eclipses of 1.3-1.8 mag depth with a period of 313 min. V503 Cyg has a 0.7-1.0 mag peak-to-peak modulation with a period of 109 min. IR Gem shows a large modulation at the orbital period of 99 min, and comparison with previous data indicates that this modulation may have an amplitude dependent on outburst phase. AH Eri reveals a 0.1-0.3 mag modulation, at a period of 42 min. Better time-resolved data on AL Com confirm the 0.4-mag variation reported by Howell and Szkody (1988) at a period of 42 min. These latter two short periods likely indicate magnetic systems. There is also some evidence of periodicity in RW UMi and WX Cet which must be confirmed with further data. 25 refs.

Szkody, P.; Howell, S.B.; Mateo, M.; Kreidl, T.J. (Washington Univ., Seattle (USA) Planetary Science Institute, Tucson, AZ (USA) Mount Wilson and Las Campanas Observatories, Pasadena, CA (USA) Lowell Observatory, Flagstaff, AZ (USA))

1989-10-01

351

Pedestrian detection in infrared images  

Microsoft Academic Search

This paper describes an approach for pedestrian detection in infrared images. The developed system has been implemented on an experimental vehicle equipped with an infrared camera and preliminarily tested in different situations. It is based on the localization of warm symmetrical objects with specific size and aspect ratio; since also road infrastructures and other road participants may have such characteristics,

M. Bertozzi; A. Broggi; P. Grisleri; T. Graf; M. Meinecke

2003-01-01

352

Infrared Detectors.  

National Technical Information Service (NTIS)

The bibliography contains unclassified and unlimited citations on Infrared Detectors. These citations are studies and analyses pertaining to detection techniques, equipment, refrigeration systems, instrumentation, sensitivity, reliability, design, measure...

1974-01-01

353

Infrared Astronomy  

NASA Astrophysics Data System (ADS)

What do we understand of the birth and death of stars? What is the nature of the tiny dust grains that permeate our Galaxy and other galaxies? And how likely is the existence of brown dwarfs, extrasolar planets or other sub-stellar mass objects? These are just a few of the questions that can now be addressed in a new era of infrared observations. IR astronomy has been revolutionised over the past few years by the widespread availability of large, very sensitive IR arrays and the success of IR satellites (IRAS in particular). Several IR space missions due for launch over the next few years promise an exciting future too. For these reasons, the IV Canary Islands Winter School of Astrophysics was dedicated to this burgeoning field. Its primary goal was to introduce graduate students and researchers from other areas to the important new observations and physical ideas that are emerging in this wide-ranging field of research. Lectures from nine leading researchers, renowned for their teaching abilities, are gathered in this volume. These nine chapters provide an excellent introduction as well as a thorough and up-to-date review of developments - essential reading for graduate students entering IR astronomy, and professionals from other areas who realise the importance that IR astronomy may have on their research.

Mampaso, A.; Prieto, M.; Sánchez, F.

2004-01-01

354

UBVRI photometry of faint field stars (Skiff, 2007)  

NASA Astrophysics Data System (ADS)

This file, originally prepared for the needs of the Lowell Observatory Near-Earth Object Search (LONEOS), contains a rough working collection of Johnson-Cousins UBVRI photometry assembled mainly from the published literature or from publicly available datasets. The V-R and V-I colors are all on the Cousins system. Most of the stars are fainter than V=10.0; the median magnitude is V=13.9, and significant numbers of stars are listed below 20mag. Besides several large surveys, several hundred small sequences in the regions of variable stars, star clusters, galaxies hosting supernovae, quasars, etc were built by determining coordinates for the sequence stars using the published finder charts. At minimum the data include V magnitudes and at least one ordinary photometric color, most commonly B-V. The data were collected for use in determining approximate photometric zero-points in wide-field imaging, with external accuracy of 0.05 mag or better. Though each dataset was vetted for consistency in magnitude and colors, neither high accuracy nor high precision is guaranteed. Obvious variable stars were omitted, but some unknown variables are inevitably included. In any given field, it is advisable use all the available stars for calibration rather than a single comparison. Several large datasets are included. The Guide Star Photometric Catalogue (GSPC, Lasker et al 1988, Cat. II/143) provides BV sequences near the centers of all the Schmidt sky survey plates. At high latitudes in the southern sky, additional data on the 5-degree Schmidt grid were obtained by Platais et al (1998, Cat. I/277) that extend the GSPC sequences to V=~16. More southern fields were observed by Demers et al (1993A&AS...99..437D and 1993A&AS...99..461D); coordinates for these stars have been determined for the first time. Nearly a thousand high-quality sequences in the northern sky have been observed by Henden, partly published in relation to work on cataclysmic variables (e.g. Cat. J/PASP/107/324) and symbiotic stars (e.g. Cat. J/A+A/143/343). Additional Henden sequences have been adopted from the files cited below at the AAVSO ftp site. These large sequences were trimmed to include only a few stars per magnitude interval, and also to omit crowded stars (no significant companions closer than 15" radius). The star coordinates are mainly from early versions of the GSC or USNO series. As such they are given to 1" precision, and in some cases small systematic errors and (now) proper motion mean their accuracy is in the 1" to 5" range. Thus for automated linkage to CCD frames, some modest search radius should be adopted to match with the catalogue. Because the file was originally intended for private use, bibliographic references were not included except in a very few instances. Usually it is straightforward to recover the source paper by inspection of the SIMBAD bibliography for specific objects. Problematic cases can be directed to the compiler (Brian Skiff). (1 data file).

Skiff, B. A.

2007-03-01

355

A faint galaxy redshift survey behind massive clusters  

SciTech Connect

This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of {approximately}20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

Frye, Brenda

1999-12-01

356

Faint recombination lines in Galactic PNe with a [WC] nucleus  

NASA Astrophysics Data System (ADS)

Aims: We present spatially resolved high-resolution spectrophotometric data for the planetary nebulae PB 8, NGC 2867, and PB 6. We have analyzed two knots in NGC 2867 and PB 6 and one in PB 8. The three nebulae are ionized by [WC] type nuclei: early [WO] for PB 6 and NGC 2867 and [WC 5-6] in the case of PB 8. Our aim is to study the behavior of the abundance discrepancy problem (ADF) in this type of planetary nebula. Methods: We measured a large number of optical recombination (ORL) and collisionally excited lines (CEL), from different ionization stages (many more than in any previous work), thus, we were able to derive physical conditions from many different diagnostic procedures. We determined ionic abundances from the available collisionally excited and recombination lines. Based on both sets of ionic abundances, we derived total chemical abundances in the nebulae using suitable ionization correction factors. Results: From CELs, we have found abundances typical of Galactic disk planetary nebulae. Moderate ADF(O++) were found for PB 8 (2.57) and NGC 2867 (1.63). For NGC 2867, abundances from ORLs are higher but still consistent with Galactic disk planetary nebulae. On the contrary, PB 8 presents a very high O/H ratio from ORLs. A high C/O was obtained from ORLs for NGC 2867; this ratio is similar to C/O obtained from CELs and with the chemical composition of the wind of the central star, indicating that there was no further C-enrichment in the star, relative to O, after the nebular material ejection. On the contrary, we found C/O<1 in PB 8. Interestingly, we obtain (C/O)ORLs/(C/O)CELs < 1 in PB 8 and NGC 2867; this added to the similarity between the heliocentric velocities measured in [O iii] and O ii lines for our three objects argue against the presence of H-deficient metal-rich knots coming from a late thermal pulse event. Based on data obtained at Las Campanas Observatory, Carnegie Institution. Table 3 is only available in electronic form at http://www.aanda.org

García-Rojas, J.; Peña, M.; Peimbert, A.

2009-03-01

357

V733 Cep (Persson's Star): A New FU Orionis Object in Cepheus  

NASA Astrophysics Data System (ADS)

Persson recently found that a faint star had appeared in a cloud in Cepheus. A CCD image shows a R~17.3 nebulous star, now known as V733 Cep, located in the L1216 = Cep F cloud at the apex of a cavity in the cloud. Infrared photometry indicates a modest infrared excess. Optical spectroscopy shows a well-defined Li I ?6707 line, and blueshifted absorption troughs at the H? and Na I D lines extending to at least 200 km s-1, indicative of a massive fast wind. An infrared 1-4 ?m spectrum of V733 Cep shows the presence of strong water vapor features, and is almost identical to a similar IR spectrum of FU Ori that is reddened by AV=8 mag. Assuming an intrinsic energy distribution similar to that of FU Ori, V733 Cep has a luminosity of about 135 Lsolar at the assumed distance of 800 pc. The star was detected by the Midcourse Space Experiment satellite at 8.3 ?m, but not by IRAS. Nor is it detected at 850 ?m, indicating that while the star possesses circumstellar material it is not surrounded by a significant cool envelope. A 12CO(3-2) map shows what appears to be a small molecular outflow along the same axis as the cavity seen in optical images. There is evidence for a limited amount of other low- and medium-mass star formation in the Cep F cloud. The totality of the evidence strongly indicates that V733 Cep is a new FU Ori-type object that must have erupted sometime between 1953 and 1984.

Reipurth, Bo; Aspin, Colin; Beck, Tracy; Brogan, Crystal; Connelley, Michael S.; Herbig, G. H.

2007-03-01

358

Confirmation of the emisison-line redshift of the BL Lac object PKS 0215 + 015  

Microsoft Academic Search

Spectroscopic observations of the BL Lac object PKS 0215 + 015 during a faint phase are presented. Lyman-alpha and C IV 1548, 1550 A broad emission lines are seen at a redshift z = 1.715. This observation confirms the earlier redshift estimate, which was based upon the absorption-line spectrum observed when the object was approximately three mag brighter. 8 references.

Craig B. Foltz

1987-01-01

359

Infrared Thermometers  

NSDL National Science Digital Library

An infrared (IR) thermometer lab offers the opportunity to give science students a chance to measure surface temperatures, utilizing off-the-shelf-technology. Students will enjoy this inquiry-based activity as they use infrared thermometers to examine various materials, metals, color surfaces, and textures on a car.

Schaefers, John

2006-01-01

360

Correlation between low level fluctuations in the x ray background and faint galaxies  

NASA Technical Reports Server (NTRS)

A correlation between low-level x-ray fluctuations in the cosmic x-ray background flux and the large numbers of galaxies found in deep optical imaging, to m(sub v) is less than or equal to 24 - 26, is desired. These (faint) galaxies by their morphology and color in deep multi-color CCD images and plate material were optically identified. Statistically significant correlations between these galaxies and low-level x-ray fluctuations at the same positions in multiple deep Einstein HRI observations in PAVO and in a ROSAT PSPC field were searched for. Our aim is to test the hypothesis that faint 'star burst' galaxies might contribute significantly to the cosmic x-ray background (at approximately 1 keV).

Tolstoy, Eline; Griffiths, R. E.

1993-01-01

361

Optical pulse-phased observations of faint pulsars with a phase-binning CCD camera  

Microsoft Academic Search

We have constructed a phase-binning CCD camera optimized for optical observations of faint pulsars. The phase- binning CCD camera combines the high quantum efficiency of a CCD with a pulse-phased time resolution capable of observing pulsars as fast as 10 ms, with no read noise penalty. The phase-binning CCD can also operate as a two- channel imaging polarimeter, obtaining pulse-phased

Brian Kern

2002-01-01

362

Increased phase synchronization and decreased cerebral autoregulation during fainting in the young  

PubMed Central

Vasovagal syncope may be due to a transient cerebral hypoperfusion that accompanies frequency entrainment between arterial pressure (AP) and cerebral blood flow velocity (CBFV). We hypothesized that cerebral autoregulation fails during fainting; a phase synchronization index (PhSI) between AP and CBFV was used as a nonlinear, nonstationary, time-dependent measurement of cerebral autoregulation. Twelve healthy control subjects and twelve subjects with a history of vasovagal syncope underwent 10-min tilt table testing with the continuous measurement of AP, CBFV, heart rate (HR), end-tidal CO2 (ETco2), and respiratory frequency. Time intervals were defined to compare physiologically equivalent periods in fainters and control subjects. A PhSI value of 0 corresponds to an absence of phase synchronization and efficient cerebral autoregulation, whereas a PhSI value of 1 corresponds to complete phase synchronization and inefficient cerebral autoregulation. During supine baseline conditions, both control and syncope groups demonstrated similar oscillatory changes in phase, with mean PhSI values of 0.58 ± 0.04 and 0.54 ± 0.02, respectively. Throughout tilt, control subjects demonstrated similar PhSI values compared with supine conditions. Approximately 2 min before fainting, syncopal subjects demonstrated a sharp decrease in PhSI (0.23 ± 0.06), representing efficient cerebral autoregulation. Immediately after this period, PhSI increased sharply, suggesting inefficient cerebral autoregulation, and remained elevated at the time of faint (0.92 ± 0.02) and during the early recovery period (0.79 ± 0.04) immediately after the return to the supine position. Our data demonstrate rapid, biphasic changes in cerebral autoregulation, which are temporally related to vasovagal syncope. Thus, a sudden period of highly efficient cerebral autoregulation precedes the virtual loss of autoregulation, which continued during and after the faint.

Ocon, Anthony J.; Kulesa, John; Clarke, Debbie; Taneja, Indu; Medow, Marvin S.

2009-01-01

363

Identification of a faint X-ray source with the W Ursae Majoris star VW Cephei  

NASA Technical Reports Server (NTRS)

The NRL instrument aboard the HEAO 1 satellite has detected a faint X-ray source, which has been identified tentatively with the contact binary star (W UMa variable) VW Cephei. Its luminosity is between 3 x 10 to the 30th and 4 x 10 to the 31st ergs/sec (0.1-10 keV), and the results suggest some variation of the X-ray flux with phase.

Carroll, R. W.; Cruddace, R. G.; Friedman, H.; Byram, E. T.; Wood, K.; Meekins, J.; Yentis, D.; Share, G. H.; Chubb, T. A.

1980-01-01

364

Short time-scale variability in the Faint Sky Variability Survey  

Microsoft Academic Search

We present the V-band variability analysis of the point sources in the Faint Sky Variability Survey on time-scales from 24 min to tens of days. We find that about one per cent of the point sources down to V = 24 are variables. We discuss the variability-detection probabilities for each field depending on field sampling, amplitude and time-scale of the

L. Morales-Rueda; P. J. Groot; T. Augusteijn; G. Nelemans; P. M. Vreeswijk; E. J. M. van den Besselaar

2006-01-01

365

The GLARE Survey - II. Faint z ~ 6 Ly? line emitters in the HUDF  

NASA Astrophysics Data System (ADS)

The galaxy population at z ~ 6 has been the subject of intense study in recent years, culminating in the Hubble Ultra Deep Field (HUDF) - the deepest imaging survey yet. A large number of high-redshift galaxy candidates have been identified within the HUDF, but until now analysis of their properties has been hampered by the difficulty of obtaining spectroscopic redshifts for these faint galaxies. Our `Gemini Lyman-Alpha at Reionization Era' (GLARE) project has been designed to undertake spectroscopic follow-up of faint (z' < 28.5) i'-drop galaxies at z ~ 6 in the HUDF. In a previous paper we presented preliminary results from the first 7.5 h of data from GLARE. In this paper we detail the complete survey. We have now obtained 36 h of spectroscopy on a single GMOS slitmask from Gemini-South, with a spectral resolution of ?/??FWHM ~ 1000. We identify five strong Ly? emitters at z > 5.5, and a further nine possible line emitters with detections at lower significance. We also place tight constraints on the equivalent width of Ly? emission for a further ten i'-drop galaxies and examine the equivalent width distribution of this faint spectroscopic sample of z ~ 6 galaxies. We find that the fraction of galaxies with little or no emission is similar to that at z ~ 3, but that the z ~ 6 population has a tail of sources with high rest-frame equivalent widths. Possible explanations for this effect include a tendency towards stronger line emission in faint sources, which may arise from extreme youth or low metallicity in the Lyman-break population at high redshift, or possibly a top-heavy initial mass function.

Stanway, Elizabeth R.; Bunker, Andrew J.; Glazebrook, Karl; Abraham, Roberto G.; Rhoads, James; Malhotra, Sangeeta; Crampton, David; Colless, Matthew; Chiu, Kuenley

2007-04-01

366

Objective lens  

NASA Technical Reports Server (NTRS)

An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

Olczak, Eugene G. (Inventor)

2011-01-01

367

Cognitive Objects.  

ERIC Educational Resources Information Center

Reflecting on obsessional play objects of infants, Hodgkin suggests that a proper understanding of these "transitional" or "cognitive" objects could lead to an educational model of a "learner" involving a number of human competencies, all developing synergistically. Contends that such a model may be truer to life than the more unified and…

Hodgkin, Robin A.

1988-01-01

368

Faint Collimated Herbig-Haro Jets from Visible Stars in L1641  

NASA Astrophysics Data System (ADS)

A population of 11 faint, collimated jets has been discovered in the northern part of the L1641 cloud in the region of HH 1/2, HH 34, and the L1641-N cluster. These jets were missed in previous imaging surveys on account of their weak emission, and they were discovered only on deep exposures with the Subaru 8 m telescope. With these new faint jets, the number of HH flows within the area surveyed has doubled. This suggests that collimated jets from young stars may be more common than previously assumed. It is noteworthy that all of the jets are associated with optically visible stars with r magnitudes ranging from 13.8 to 22.0. The driving sources of jets in regions flooded by ultraviolet radiation from nearby OB stars are known to be excavated by photoionization, and in three cases remnant H? emission envelopes are found associated with the sources, although the more benign environment in the region observed here, about 10 pc distant from the Orion Nebula Cluster, makes the optical visibility of all these sources rather surprising. Such faint jets from visible stars represent either the final vestiges of the outflow phenomenon, or they are triggered by disturbances of the remnant disks, possibly initiated by the orbital evolution of binaries that spiral in to form close binaries. Among the known H? emission stars within the region surveyed, 8% are found to be associated with jets.

Reipurth, Bo; Aspin, Colin; Bally, John; Tobin, John J.; Walawender, Josh

2010-09-01

369

APPLICATIONS OF INFRARED THERMOGRAPHY IN ANIMAL PRODUCTION  

Microsoft Academic Search

This review presents the application and use of infrared thermography (IRT) in production animals. IRT is a non-invasive and non-contact heat detecting technology. An infrared camera measures the emitted infrared radiation from an object and then uses this information to create images (thernograms). These thermograms are evaluated by a specially analyzing software program. In live organisms, changes in vascular circulation

Ivana KNÍ KOVÁ; Petr KUNC

2007-01-01

370

Uncovering The Nature Of Optically-faint Chandra X-ray Clusters  

NASA Astrophysics Data System (ADS)

We present analysis of infrared observations of eight extended Chandra X-ray sources that were serendipitously discovered as part of the Chandra Multiwavelength Project (ChaMP). These X-ray sources were selected as having no optical counterparts in NOAO 4-meter observations in gri passbands (limiting depth i 23.5). Since these ``X-ray only" clusters are likely to be at high redshift, we have acquired J- and Ks-band imaging of these objects using PANIC on the Magellan telescope. Our Magellan/PANIC data allows us to confirm the high redshift nature of our sample by measuring the cluster red sequence, and ascertaining the properties of galaxies in these distant systems.

Corbett, Stephanie; Barkhouse, W.; Green, P.; Smith, M.; Vikhlinin, A.; Kim, D.

2011-01-01

371

Infrared Measurement  

NASA Technical Reports Server (NTRS)

A Jet Propulsion Laboratory Technical Support Package (TSP) describing a technique for processing data from an infrared radiometer assisted a manufacturer of laminates for printed circuit boards. To reduce emissions and lower the cost of producing prepreg (a continuous glass cloth, or web, impregnated with epoxy resin and partially cured by applying heat), Norplex Oak switched to infrared treating towers. The TSP confirmed the company's computer prediction of heat flux patterns, provided information that allowed the company to modify infrared treaters for consistency, and furnished a basis for development of optimal heater placements. The treaters are now successfully operating at increased speeds with improved product consistency.

1992-01-01

372

Method for imaging a concealed object  

DOEpatents

A method for imaging a concealed object is described and which includes a step of providing a heat radiating body, and wherein an object to be detected is concealed on the heat radiating body; imaging the heat radiating body to provide a visibly discernible infrared image of the heat radiating body; and determining if the visibly discernible infrared image of the heat radiating body is masked by the presence of the concealed object.

Davidson, James R [Idaho Falls, ID; Partin, Judy K [Idaho Falls, ID; Sawyers, Robert J [Idaho Falls, ID

2007-07-03

373

Radio to X-Ray distribution of BL Lac Objects (Giommi+, 1995)  

NASA Astrophysics Data System (ADS)

We present multifrequency spectra of a large number of radio and X-ray selected BL Lacertae objects constructed using non-simultaneous archival data. The data were obtained using the European Space Information System (ESIS) and are from several radio and optical catalogues, the IRAS Faint Source Catalogue, the Einstein and the EXOSAT databases. The sample includes 121 BL Lacs that have been extracted from the 1Jy (1991ApJ...374..431S) and the S4 (1994A&AS..103..349S) radio surveys, the Einstein IPC Slew Survey, the Einstein Extended Medium Sensitivity Survey (EMSS), the EXOSAT High Galactic Latitude Survey, and from the compilations of Giommi et al. (1990ApJ...356..432G) and Veron & Veron (1993ESOSR..13....1V). We find that the shape of the radio to infra-red spectrum of Radio Selected and X-ray Selected BL Lacs is very similar. The difference between these two classes of objects is instead evident in the optical/X-ray part of the spectrum. The classical radio discovered BL Lacs are characterized by an energy spectrum with a sharp cutoff in the IR/optical band while in most of the X-ray discovered objects the turnover is located near the UV/X-ray band or at higher frequencies. For a given X-ray flux this diversity can give rise to radio fluxes different by a factor of 100 or more. We argue that BL Lac objects may be a single population of sources characterized by a wide range of energy cutoffs. In this scenario BL Lacs discovered in radio surveys are representative of the entire population, while objects characterized by an energy break near the X-ray band, which are abundantly detected at X-ray frequencies, are intrinsically a small minority. (5 data files).

Giommi, P.; Ansari, S. G.; Micol, A.

1995-02-01

374

Radio to X-ray energy distribution of BL Lacertae objects.  

NASA Astrophysics Data System (ADS)

We present multifrequency spectra of a large number of radio and X-ray selected BL Lacertae objects constructed using non-simultaneous archival data. The data were obtained using the European Space Information System (ESIS) and are from several radio and optical catalogues, the IRAS Faint Source Catalogue, the Einstein and the EXOSAT databases. The sample includes 121 BL Lacs that have been extracted from the 1Jy and the S4 radio surveys (Stickel et al. 1991; Stickel & Kuehr 1994), the Einstein IPC Slew Survey, the Einstein Extended Medium Sensitivity Survey (EMSS), the EXOSAT High Galactic Latitude Survey, and from the compilations of Giommi et al. (1990), and Veron & Veron (1993). We find that the shape of the radio to infra-red spectrum of Radio Selected and X-ray Selected BL Lacs is very similar. The difference between these two classes of objects is instead evident in the optical/X-ray part of the spectrum. The classical radio discovered BL Lacs are characterized by an energy spectrum with a sharp cutoff in the IR/optical band while in most of the X-ray discovered objects the turnover is located near the UV/X-ray band or at higher frequencies. For a given X-ray flux this diversity can give rise to radio fluxes different by a factor of 100 or more. We argue that BL Lac objects may be a single population of sources characterized by a wide range of energy cutoffs. In this scenario BL Lacs discovered in radio surveys are representative of the entire population, while objects characterized by an energy break near the X-ray band, which are abundantly detected at X-ray frequencies, are intrinsically a small minority.

Giommi, P.; Ansari, S. G.; Micol, A.

1995-02-01

375

Trusted Objects  

SciTech Connect

In the world of computers a trusted object is a collection of possibly-sensitive data and programs that can be allowed to reside and execute on a computer, even on an adversary's machine. Beyond the scope of one computer we believe that network-based agents in high-consequence and highly reliable applications will depend on this approach, and that the basis for such objects is what we call ''faithful execution.''

CAMPBELL,PHILIP L.; PIERSON,LYNDON G.; WITZKE,EDWARD L.

1999-10-27

376

Automated Morphological Classification in Deep Hubble Space Telescope UBVI Fields: Rapidly and Passively Evolving Faint Galaxy Populations  

NASA Astrophysics Data System (ADS)

We analyze deep Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) images in U, B, V, I using artificial neural network (ANN) classifiers, which are based on galaxy surface brightness and light profile (but not on color nor on scale length, rhl). The ANN distinguishes quite well between E/S0, Sabc, and Sd/Irr+M galaxies (M for merging systems) for BJ <~ 27 mag. We discuss effects from the cosmological surface brightness (SB) dimming and from the redshifted UV morphology on the classifications, and we correct for the latter. We present classifications in UBVI from (a) four independent human classifiers; (b) ANNs trained on V606 and I814 images; and (c) an ANN trained on images in the rest-frame UBV according to the expected redshift distribution as a function of BJ. For each of the three methods, we find that the fraction of galaxy types does not depend significantly on wavelength, and that they produce consistent counts as a function of type. The median scale length at BJ ~= 27 mag is rhl ~= 0."25--0."3 (1--2 kpc at z ~ 1--2). Early- and late-type galaxies are fairly well separated in BVI color-magnitude diagrams for B <~ 27 mag, with E/S0 galaxies being the reddest and Sd/Irr+M galaxies generally blue. We present the B-band galaxy counts for five WFPC2 fields as a function of morphological type for BJ <~ 27 mag. E/S0 galaxies are only marginally above the no-evolution predictions, and Sabc galaxies are at most 0.5 dex above the nonevolving models for BJ >~ 24 mag. The faint blue galaxy counts in the B band are dominated by Sd/Irr+M galaxies and can be explained by a moderately steep local luminosity function (LF) undergoing strong luminosity evolution. We suggest that these faint late-type objects (24 mag <~ BJ <~ 28 mag) are a combination of low-luminosity lower redshift dwarf galaxies, plus compact star-forming galaxies and merging systems at z ~= 1--3, possibly the building blocks of the luminous early-type galaxies seen today.

Odewahn, Stephen C.; Windhorst, Rogier A.; Driver, Simon P.; Keel, William C.

1996-11-01

377

Atlas of Light Curves of Faint Mira-Type Stars. Statistical Relations Between the Characteristics of Smoothed Phase Light Curves  

NASA Astrophysics Data System (ADS)

We propose a set of the photometric parameters which could be useful for the classiffication of the pulsating Mira-type stars and related objects and determination of the EAGB and TPAGB stages of the stellar evolution. To solve this problem, the light curves of faint Mira- type stars and of the semi-regular variable V411 Sct were approximated using the program FDCN, which computes a trigonometric polynomial of a statistically optimal degree (I.L.Andronov, 1994, 2003). The at las of statistically optimal fits of the phase curves of 34 long-period is presented, based on digitized data from the scanned "Atlas" by P. Maffei and G.Tosti (http://astro.fisica.unipg.it/atlasmaffei/main.htm). Some statistical relations between the parameters of the trigonometrical polynomial approximation of the phase curve are analyzed. for an additional criterion of detailed classiffication of long-perodic variables, we used various parameters, e.g. "period", "amplitude", "asymmetry", "slope of the ascending branch", "characteristic time of brightening by 1m": Discussion of the results is presented.

Kudashkina, L. S.; Andronov, I. L.

2010-12-01

378

Why Infrared?  

ERIC Educational Resources Information Center

Discusses applications of techniques developed for the remote sensing of infrared radiation. In addition to military applications, remote sensing has become important in collecting environmental data and detecting ecological problems. (JR)

Harris, J. R.

1973-01-01

379

The SCUBA HAlf Degree Extragalactic Survey (SHADES) - V. Submillimetre properties of near-infrared-selected galaxies in the Subaru/XMM -Newton deep field  

NASA Astrophysics Data System (ADS)

We have studied the submillimetre (submm) properties of the following classes of near-infrared-selected (NIR-selected) massive galaxies at high redshifts: BzK-selected star-forming galaxies (BzKs); distant red galaxies (DRGs); and extremely red objects (EROs). We used the SCUBA HAlf Degree Extragalactic Survey (SHADES), the largest uniform submm survey to date. Partial overlap of SIRIUS/NIR images and SHADES in Subaru/XMM-Newton deep field has allowed us to identify four submm-bright NIR-selected galaxies, which are detected in the mid-IR, 24? m, and the radio, 1.4GHz. We find that all of our submm-bright NIR-selected galaxies satisfy the BzK selection criteria, i.e. BzK ? (z - K)AB - (B - z)AB >= -0.2, except for one galaxy whose B - z and z - K colours are however close to the BzK colour boundary. Two of the submm-bright NIR-selected galaxies satisfy all of the selection criteria we considered, i.e. they belong to the BzK-DRG-ERO overlapping population, or `extremely red' BzKs. Although these extremely red BzKs are rare (0.25 arcmin-2), up to 20 per cent of this population could be submm galaxies. This fraction is significantly higher than that found for other galaxy populations studied here. Via a stacking analysis, we have detected the 850-? m flux of submm-faint BzKs and EROs in our SCUBA maps. While the contribution of z ~ 2 BzKs to the submm background is about 10-15 per cent and similar to that from EROs typically at z ~ 1, BzKs have a higher fraction (~30 per cent) of submm flux in resolved sources compared with EROs and submm sources as a whole. From the spectral energy distribution (SED) fitting analysis for both submm-bright and submm-faint BzKs, we found no clear signature that submm-bright BzKs are experiencing a specifically luminous evolutionary phase, compared with submm-faint BzKs. An alternative explanation might be that submm-bright BzKs are more massive than submm-faint ones.

Takagi, T.; Mortier, A. M. J.; Shimasaku, K.; Coppin, K.; Pope, A.; Ivison, R. J.; Hanami, H.; Serjeant, S.; Clements, D. L.; Priddey, R. S.; Dunlop, J. S.; Takata, T.; Aretxaga, I.; Chapman, S. C.; Eales, S. A.; Farrah, D.; Granato, G. L.; Halpern, M.; Hughes, D. H.; van Kampen, E.; Scott, D.; Sekiguchi, K.; Smail, I.; Vaccari, M.

2007-11-01

380

THE WFC3 INFRARED SPECTROSCOPIC PARALLEL (WISP) SURVEY  

SciTech Connect

We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of {approx}90 independent, high-latitude fields by observing in the pure-parallel mode with the Wide Field Camera Three on the Hubble Space Telescope for a total of {approx}250 orbits. Spectra are obtained with the G{sub 102} ({lambda} = 0.8-1.17 {mu}m, R {approx}210) and G{sub 141} grisms ({lambda} = 1.11-1.67 {mu}m, R {approx}130), together with direct imaging in the J and H bands (F110W and F140W, respectively). In the present paper, we present the first results from 19 WISP fields, covering approximately 63 arcmin{sup 2}. For typical exposure times ({approx}6400 s in G{sub 102} and {approx}2700 s in G{sub 141}), we reach 5{sigma} detection limits for emission lines of f {approx} 5 x 10{sup -17} erg s{sup -1} cm{sup -2} for compact objects. Typical direct imaging 5{sigma} limits are 26.3 and 26.1 mag. (AB) in F110W and F140W, respectively. Restricting ourselves to the lines measured with the highest confidence, we present a list of 328 emission lines, in 229 objects, in a redshift range 0.3 < z < 3. The single-line emitters are likely to be a mix of H{alpha} and [O III]5007,4959 A, with H{alpha} predominating. The overall surface density of high-confidence emission-line objects in our sample is approximately 4 per arcmin{sup 2}. These first fields show high equivalent width sources, active galactic nucleus, and post-starburst galaxies. The median observed star formation rate (SFR) of our H{alpha}-selected sample is 4 M{sub sun} yr{sup -1}. At intermediate redshifts, we detect emission lines in galaxies as faint as H{sub 140} {approx} 25, or M{sub R} < -19, and are sensitive to SFRs down to less than 1 M{sub sun} yr{sup -1}. The slitless grisms on WFC3 provide a unique opportunity to study the spectral properties of galaxies much fainter than L* at the peak of the galaxy assembly epoch.

Atek, H.; Scarlata, C.; Colbert, J. W.; Shim, H. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Malkan, M.; Ross, N. R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90024 (United States); McCarthy, P.; Dressler, A. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Teplitz, H. I. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Siana, B.; Bridge, C. [Department of Astronomy, Caltech, Pasadena, CA 91125 (United States); Henry, A.; Martin, C. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Bunker, A. J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, OX13RH (United Kingdom); Fosbury, R. A. E. [Space Telescope-European Coordinating Facility, Garching (Germany)

2010-11-01

381

OHANA: representative science objectives  

NASA Astrophysics Data System (ADS)

In this poster, we examine the science potential of an 800 meter interferometer such as the OHANA Array. The working assumptions are a K = 12 limiting magnitude, a 0.5 milliarcsecond resolution at K band, and a small (diffraction limit of individual telescope) field of view. The science cases described herein are by no means exhaustive and perhaps not even the ones that will eventually be carried out, but serve to illustrate the potential of the array. We expect that operation of the array will be proposal driven, so the actual science will come from the Mauna Kea communities. Our philosophy is that any measurement that can be made at a dedicated interferometer facility should not be a strong driver for OHANA. Therefore the science areas discussed in the poster focus on very high angular resolution measurements of faint sources. In some cases, science which can be addressed with simpler or dedicated facilities at an exploratory level can be carried to a significant new capability with OHANA. A limitng magnitude of 12 was obtained by simple computations, but first tests on the sky with the injection module (See adjacent poster on Phase I) will help narrow down this figure. At such sensitivity, Cepheid pulsations can be studied in considerable detail for a wide range of stellar parameters, leading to enhanced confidence in the accuracy of their use for distance measurement with minimal extrapolation or inferrence. The disk/star interaction zone in young stellar objects can be resolved with unprecedented detail for a range of masses and ages, providing direct information about the jet formation region, accretion rates and disk conditions. The broad line region of active galactic nuclei can be studied in a large number of sources of differing characteristics, testing specific models for AGN nuclear structure. For OHANA Phase III, a dual-star phase tracking capability is planned. With the resulting increased sensitivity, direct brown dwarf diameter measurement will provide a strong check on evolution models. Microlensing events could be resolved and provide unique new information about the lensing and the lensed objects.

Lai, Olivier; Ridgway, Stephen T.; Berger, Jean-Philippe; Dougados, Catherine; Coudé du Foresto, Vincent; Guyon, Olivier; Lachaume, Regis; Magnier, Eugene; Malbet, Fabien; Menard, Francois; Mourard, Denis; Perrin, Guy S.; Sol, Helene; Warren, Steve; Woillez, Julien

2003-02-01

382

Spaceplace: See the Infrared Photo Album!  

NSDL National Science Digital Library

Younger students will enjoy viewing these images of ordinary objects rendered in the infrared part of the electromagnetic spectrum. They can access a virtual "camera" and see pictures of animals, people, and other objects in either infrared or visible light. The camera allows them to magnify the images; a color map provides a relative scale for temperatures. A Spanish translation is available.

383

A temporal and spatial analysis of cavitation on mechanical heart valves by observing faint light emission.  

PubMed

Cavitation on mechanical heart valves (MHVs) could cause the mechanical failure of the occluder. A simple and reliable in vitro test method to evaluate cavitation potential must be developed. The bubble implosion damages the MHV material; thus, observing the behavior of the bubble implosion is essential. According to sonoluminescence, the collapsing cavity emits faint light. Therefore, in this study, the bubble collapse was analyzed both temporally and spatially by observing faint light emission. A photon counting system has been developed using a photomultiplier tube (H7360-01, Hamamatsu Photonics, Japan). The highest time resolution of this system is 5 microsec. A quartz optical fiber bundle of 2 mm diameter can be connected to this photomultiplier tube and traversed two-dimensionally over the MHV. The closure of the MHV triggers the photon counter, and the photons through 500 beats are recorded and integrated. A 20 mm Björk-Shiley valve was submerged in a water tank containing 10 L deionized water, and the pressure difference of 120 mm Hg was exerted on the valve at a rate of 60 bpm with a pulse duplicator. Approximately 700 microsec after the valve closure, light emission was detected along the edge of the occluder on the inflow side in the major orifice. Then, approximately 1,000 microsec after the closure, light along the occluder's edge in the minor orifice was recorded as well. Compared with the analysis, using a stroboscope and a high-speed camera, faint light was emitted from the collapsing cavities. In conclusion, sonoluminescnece was successfully observed around the MHV, and the photon counting technique and the traversing mechanism of the optical fiber bundle revealed the temporal and spatial distribution of the cavity collapse on the MHV. PMID:15171483

Takiura, Koki; Chinzei, Tsuneo; Abe, Yusuke; Isoyama, Takashi; Saito, Itsuro; Mochizuki, Shuichi; Imachi, Kou

2004-01-01

384

Improving the Visible and Infrared Contrast Ratio of Microshutter Arrays  

NASA Technical Reports Server (NTRS)

Three device improvements have been developed that dramatically enhance the contrast ratio of microshutters. The goal of a microshutter is to allow as much light through as possible when the shutters are in the open configuration, and preventing any light from passing through when they are in the closed position. The ratio of the transmitted light that is blocked is defined here as the contrast ratio. Three major components contribute to the improved performance of these microshutters: 1. The precise implementation of light shields, which protect the gap around the shutters so no light can leak through. It has been ascertained that without the light shield there would be a gap on the order of 1 percent of the shutter area, limiting the contrast to a maximum of 100. 2. The precise coating of the interior wall of each microshutter was improved with an insulator and metal using an angle deposition technique. The coating prevents any infrared light that finds an entrance on the surface of the microshutter cell from being emitted from a sidewall. Since silicon is in effect transparent to any light with a wavelength longer than .1 micrometer, these coatings are essential to blocking any stray signals when the shutters are closed. 3. A thin film of molybdenum nitride (MoN) was integrated onto the surface of the microshutter blade. This film provides the majority of light blockage over the microshutter and also ensures that the shutter can be operated over a wide temperature range by maintaining its flatness. These improvements were motivated by the requirements dictated by the James Webb Space Telescope NIRSpec instrument. The science goals of the NIRSpec require observing some of the very faintest objects in a given field of view that also may contain some very bright objects. To observe the faint objects, the light from the bright objects - which could be thousands of times brighter - must be completely blocked. If a closed microshutter is even slightly transmissive, a very bright object will still transmit a small signal, which can be larger than a signal from a very faint object transmitted through an open shutter. Since this situation can completely corrupt the results, it was necessary that the closed shutters be able to attenuate light by at least a factor of 2,000. There currently exist four flight-quality microshutter arrays that have been fully or are currently undergoing testing and the results support that the three improvements described above have successfully led to contrast levels greater than 50,000 in over 99 percent of the microshutters at an operating temperature of 35 K. Applications for these high-contrast microshutters are in the photomask generation and stepper equipment used to make integrated circuits and microelectromechanical (MEMS) devices. Since microshutters are a reconfigurable optical element, their versatility in these industries provides an improvement over printed masks and fixed projection alignment systems.

Jhabvala, Murzy; Li, Mary; Moseley, Harvey; Franz, Dave; Yun, Zheng; Kutyrev, Alexander

2009-01-01

385

Hubble Provides Infrared View of Jupiter's Moon, Ring, and Clouds  

NASA Technical Reports Server (NTRS)

Probing Jupiter's atmosphere for the first time, the Hubble Space Telescope's new Near Infrared Camera and Multi-Object Spectrometer (NICMOS) provides a sharp glimpse of the planet's ring, moon, and high-altitude clouds.

The presence of methane in Jupiter's hydrogen- and helium-rich atmosphere has allowed NICMOS to plumb Jupiter's atmosphere, revealing bands of high-altitude clouds. Visible light observations cannot provide a clear view of these high clouds because the underlying clouds reflect so much visible light that the higher level clouds are indistinguishable from the lower layer. The methane gas between the main cloud deck and the high clouds absorbs the reflected infrared light, allowing those clouds that are above most of the atmosphere to appear bright. Scientists will use NICMOS to study the high altitude portion of Jupiter's atmosphere to study clouds at lower levels. They will then analyze those images