These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

NIFTE: The Near Infrared Faint-Object Telescope Experiment  

NASA Technical Reports Server (NTRS)

The high sensitivity of large format InSb arrays can be used to obtain deep images of the sky at 3-5 micrometers. In this spectral range cool or highly redshifted objects (e.g. brown dwarfs and protogalaxies) which are not visible at shorter wavelengths may be observed. Sensitivity at these wavelengths in ground-based observations is severly limited by the thermal flux from the telescope and from the earth's atmosphere. The Near Infrared Faint-Object Telescope Experiment (NIFTE), a 50 cm cooled rocket-borne telescope combined with large format, high performance InSb arrays, can reach a limiting flux less than 1 micro-Jy(1-sigma) over a large field-of-view in a single flight. In comparison, the Infrared Space Observatory (ISO) will require days of observation to reach a sensitivity more than one order of magnitude worse over a similar area of the sky. The deep 3-5 micrometer images obtained by the rocket-borne telescope will assist in determining the nature of faint red objects detected by ground-based telescopes at 2 micrometers, and by ISO at wavelengths longer than 5 micrometers.

Bock, James J.; Lange, Andrew E.; Matsumoto, T.; Eisenhardt, Peter B.; Hacking, Perry B.; Schember, Helene R.

1994-01-01

2

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

3

The Danish Faint Object Spectrograph and Camera  

E-print Network

Chapter 2 The Danish Faint Object Spectrograph and Camera The Danish Faint Object Spectrograph.3mm Camera linear field 30:7 \\Theta 30:7mm Reduction ratio 0.58 On the Danish 1.54m (nominal values. THE DANISH FAINT OBJECT SPECTROGRAPH AND CAMERA \\Gamma100 ffi C. Beware that the bias level is temperature

4

X-ray Counterparts of Infrared Faint Radio Sources  

NASA Astrophysics Data System (ADS)

Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2infrared fluxes, will constrain the class-specific SED.

Schartel, Norbert

2011-10-01

5

A New System of Faint Near-Infrared Standard Stars  

Microsoft Academic Search

A new grid of 65 faint near-infrared standard stars is presented. They are spread around the sky, lie between 10th and 12th magnitude at K, and are measured in most cases to precisions better than 0.001 mag in the J, H, K, and K_s bands; the latter is a medium-band modified K. A secondary list of red stars suitable for

S. E. Persson; D. C. Murphy; W. Krzeminski; M. Roth M. J. Rieke

1998-01-01

6

The Faint Infrared Grism Survey (FIGS)  

NASA Astrophysics Data System (ADS)

We propose uniquely deep near-infrared spectroscopy using the WFC3 IR grism down to a continuum limit of J=26.5, and line flux limit 4e-18 ergs/cm^2/s, yielding spectra of 6000 sources in 4 fields. Only Hubble can achieve such sensitivity, as we have demonstrated in our previous deep grism surveys with ACS.With the deep spectra obtained in the FIGS survey we will:(1) Probe the reionization epoch by spectroscopy of galaxies at z = 5.5-8.5, whether or not they show Lyman-alpha (LyA) line emission. Continuum breaks are hard to detect from the ground and LyA lines may be scarce at these redshifts. Spectroscopic redshifts will probe galaxy clustering and improve luminosity measurements, thereby improving estimatesof reionizing photons by at least 40%.(2) Robustly measure the fraction of galaxies with high EW LyA, to measure the neutral fraction of the IGM. We will be sensitive to LyA lines in the central period of reionization where we expect to see a change in LyA fraction.(3) Illuminate the formation processes of early type galaxies at 1

Malhotra, Sangeeta

2014-10-01

7

The thermal control system of the Faint Object Camera \\/FOC  

Microsoft Academic Search

The thermal control system of the Faint Object Camera (FOC) is described. The very demanding image stability requirements in the order of 3 microns requires an active thermal control system of the Optical Bench Enclosure (OBE) where the optical relays and the detectors are housed. The analytically derived requirements of the thermal control system are as follows: (1) long term

E. K. J. Jakel; W. Erne; G. Soulat

1980-01-01

8

Fainting  

MedlinePLUS

... your face. Before fainting, you may also feel weak, nauseated, and have the sense that your vision ... pressure, and allergies (these drugs may cause a drop in blood pressure) Drug or alcohol use Hyperventilation ...

9

Fainting  

MedlinePLUS

... brain does not get enough oxygen. You lose consciousness, or "pass out," for a brief time (usually ... Taking longer than a few seconds to regain consciousness Fainting when you turn your head to the ...

10

Fainting  

MedlinePLUS

... exercising too much or working out in excessive heat and not drinking enough fluids (so the body becomes dehydrated ). Fainting also can be triggered by other causes of dehydration, as well as hunger or exhaustion. Sometimes just standing for a very long time ...

11

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

12

Calibration and operation of the Faint Object Spectrograph  

NASA Technical Reports Server (NTRS)

The design and basic performance characteristics of the Faint Object Spectrograph (FOS), one of five instruments built for use on the Space Telescope observatory, is summarized briefly. The results of the recently completed instrument-level calibration are presented with special emphasis on issues affecting plans for FOS astronomical observations. Examples include such fundamental characteristics as: limiting magnitudes (system sensitivity and noise figures), spectral coverage and resolution, scattered light properties, and instrumental polarization and modulation efficiencies. Also gated toward intended users, a rather detailed description of FOS operating modes is given. The discussion begins with the difficulties anticipated during target acquisition and their hoped-for resolution. Both the 'normal' spectroscopic operating modes of the FOS and its 'exotic' features (e.g. spectropolarimetric, time-tagged, and time-resolved modes) are presented. The paper concludes with an overview of the activities to assure proper alignment and operation of the FOS within the entire Space Telescope system (orbital and ground-based).

Harms, R.; Beaver, E.; Burbidge, E.; Hier, R.; Allen, R.; Angel, R.; Bartko, F.; Bohlin, R.; Ford, H.; Davidson, A.

1984-01-01

13

High voltage potting for the Faint Object Camera (FOC)  

NASA Astrophysics Data System (ADS)

Potting the high voltage parts on the photon detector of the Faint Object Camera (FOC) for the Space Telescope is described. The detector is required to have very high gain to provide a logic level signal for digital processing. Gain is provided by an image intensifier and a video camera tube, the former operating at up to 42KV (normally at 38KV) and the latter in the range -6.5 to -12KV (normally -10KV). Experience in developing the detector (including catastrophic failures) shows that when high voltage circuits are potted it is essential to define and control potentials on all surfaces. It is strongly recommended that a dummy unit be potted with pressure and stress gages to determine the forces involved in curing and environmental test cycles. The application of partial discharge testing is essential for assemblies and desirable for past screening (cables, correction techniques at least). Potting should be under vacuum and scrupulous attention must be paid to cleanliness of surfaces to be potted and all containers and equipment used for priming and potting.

Thomas, R.

1985-11-01

14

Serendipitous Background Monitoring of the Hubble Space Telescope's Faint Object Spectrograph  

E-print Network

Serendipitous Background Monitoring of the Hubble Space Telescope's Faint Object Spectrograph John Baltimore, MD 21218 ABSTRACT The nature of the Hubble Space Telescope's (HST) low Earth orbit imposes The Faint Object Spectrograph on board the Hubble Space Telescope contains two digicon detectors each

Schneider, Glenn

15

Faint Object Spectrograph Instrument Handbook v. 6.0  

NASA Astrophysics Data System (ADS)

This Handbook describes The Faint Object Spectrograph (FOS) and its use for Cycle 6 of the Hubble Space Telescope General Observer program. Many presentations have been updated from previous versions, especially those pertaining to target acquisition, brightness limits, and in- strumental sensitivities needed for exposure and S/N calculations. This Handbook draws upon dis- cussions from earlier versions of the Handbook, notably the Version 1.0 FOS Instrument Handbook (Ford 1985), the Supplement to the Version 1.0 Instrument Handbook (Hartig 1989), and the Version 5.0 Handbook (Kinney, 1994). Only the current document should be used for Cy- cle 6. The detectors are described in detail by Harms et al (1979) and Harms (1982). This version of the FOS Instrument Handbook is for the post-COSTAR refurbished tele- scope. The change in focal length introduced by the addition of COSTAR affects the aperture sizes as projected on the sky. However, the pre-COSTAR aperture designations used in the Remote Pro- posal Submission System, version 2 (RPS2) and in the Project Data Base (PDB) have not been changed. Apertures are referred to throughout this document by their size followed in parentheses by their RPS2 exposure level designation (in Courier typeface). Indeed, all RPS2 desig- nations, which are used for proposal preparation, will be denoted in Courier typeface in this Hand- book. For example, the largest circular aperture is referred to as the 0.9'' (1.0) aperture, while the smallest paired apertures are referred to as the 0.09'' paired (0.1-PAIR)apertures.

Keyes, C. D.; et al.

1995-06-01

16

Neutral Gas Outflows and Inflows in Infrared-Faint Seyfert Galaxies  

NASA Astrophysics Data System (ADS)

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. Here we present results from a search for outflows in 35 infrared-faint Seyferts with 109.9 < LIR / LSun < 1011, or, equivalently, star formation rates (SFR) of 0.4 - 9 solar masses per year, 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. This work was supported in part by NSF through contract AST/EXC 0606932.

Krug, Hannah B.; Rupke, D. S. N.; Veilleux, S.

2010-01-01

17

Measurements of the sky background using the HST Faint Object Camera  

Microsoft Academic Search

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 Lyalpha and neutral oxygen airglow emission lines

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

1994-01-01

18

On the Automated and Objective Detection of Emission Lines in Faint-Object Spectroscopy  

NASA Astrophysics Data System (ADS)

Modern spectroscopic surveys produce large spectroscopic databases, generally with sizes well beyond the scope of manual investigation. The need arises, therefore, for an automated line detection method with objective indicators for detection significance. In this paper, we present an automated and objective method for emission line detection in spectroscopic surveys and apply this technique to observed spectra from a Ly? emitter survey at z ˜ 2.7, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO). The basic idea is to generate on-source (signal plus noise) and off-source (noise only) mock observations using Monte Carlo simulations, and calculate completeness and reliability values, (C,R), for each simulated signal. By comparing the detections from real data with the Monte Carlo results, we assign the completeness and reliability values to each real detection. From 1574 spectra, we obtain 881 raw detections and, by removing low reliability detections, we finalize 652 detections from an automated pipeline. Most of high completeness and reliability detections, (C,R) ? (1.0,1.0), are robust detections when visually inspected; the low C and R detections are also marginal on visual inspection. This method of detecting faint sources is dependent on the accuracy of the sky subtraction.

Hong, Sungryong; Dey, Arjun; Prescott, Moire K. M.

2014-12-01

19

Astrometry and Photometry of Faint, High Priority Solar System Objects  

NASA Astrophysics Data System (ADS)

We propose to use 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. Many asteroids and comets are being lost owing to insufficient followup astrometry, but only the most important ones can continue to be observed with the limited resources available. Objects flagged as high scientific priority and urgently in need of further observations include freshly discovered virtual impactors (VIs) and NEOs discovered by the soon-to-be reactivated WISE 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 our need to reach fainter magnitudes. 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 previously determined by WISE in need of astrometry.

McMillan, Robert S.; Larsen, Jeffrey A.; Scotti, James V.; Bressi, Terrence H.; Maleszewski, Chester K.

2014-02-01

20

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

21

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

22

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

Microsoft Academic Search

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

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

2008-01-01

23

In-flight performance of the Faint Object Camera of the Hubble Space Telescope  

Microsoft Academic Search

An overview of the Faint Object Camera and its performance to date is presented. In particular, the detector's efficiency, the spatial uniformity of response, distortion characteristics, detector and sky background, detector linearity, spectrography, and operation are discussed. The effect of the severe spherical aberration of the telescope's primary mirror on the camera's point spread function is reviewed, as well as

P. Greenfield; F. Paresce; D. Baxter; P. Hodge; R. Hook; P. Jakobsen; R. Jedrzejewski; A. Nota; W. B. Sparks; N. Towers

1991-01-01

24

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

25

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

26

Hubble Space Telescope Faint Object Camera calculated point-spread functions.  

PubMed

A set of observed noisy Hubble Space Telescope Faint Object Camera point-spread functions is used to recover the combined Hubble and Faint Object Camera wave-front error. The low-spatial-frequency wave-front error is parameterized in terms of a set of 32 annular Zernike polynomials. The midlevel and higher spatial frequencies are parameterized in terms of set of 891 polar-Fourier polynomials. The parameterized wave-front error is used to generate accurate calculated point-spread functions, both pre- and post-COSTAR (corrective optics space telescope axial replacement), suitable for image restoration at arbitrary wavelengths. We describe the phase-retrieval-based recovery process and the phase parameterization. Resultant calculated precorrection and postcorrection point-spread functions are shown along with an estimate of both pre- and post-COSTAR spherical aberration. PMID:18250862

Lyon, R G; Dorband, J E; Hollis, J M

1997-03-10

27

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

28

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

29

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

30

Observations of SN 1987A with the COSTAR-corrected Faint Object Camera  

NASA Astrophysics Data System (ADS)

New near-ultraviolet and visible (O III) observations of SN 1987A obtained 2511 and 2533 days after outburst with the Corrective Optics Space Telescope Axial Replacement (COSTAR) corrected Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) are presented. Even though the supernova is now very faint (m approximately equal to 19), the new data are of dramatically higher quality than those obtained previously with the aberrated telescope. The images -- which are now no longer hampered by the spherical aberration halos of the two nearby companion stars -- reveal a well-resolved symmetrical expanding envelope that can be traced out to a radius of approximately equal to 275 mas or approximately equal to 9400 km/s in the near-UV. The apparent diameter of the ejecta has grown to 255 +/- 2 mas Full Width at Half Maximum (FWHM) in the near-UV and 167 +/- 5 mas (FWHM) in the visible, in close agreement with the expansion rates inferred from earlier FOC observations obtained on days 1275 and 1754. The improved shell-like crescent has started to form within the inner approximately equals 60 mas core of the nebula.

Jakobsen, P.; Jedrzejewski, R.; Macchetto, F.; Panagia, N.

1994-11-01

31

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

32

Hubble Space Telescope faint object camera instrument handbook (Post-COSTAR), version 5.0  

NASA Technical Reports Server (NTRS)

The faint object camera (FOC) is a long-focal-ratio, photon-counting device capable of taking high-resolution two-dimensional images of the sky up to 14 by 14 arc seconds squared in size with pixel dimensions as small as 0.014 by 0.014 arc seconds squared in the 1150 to 6500 A wavelength range. Its performance approaches that of an ideal imaging system at low light levels. The FOC is the only instrument on board the Hubble Space Telescope (HST) to fully use the spatial resolution capabilities of the optical telescope assembly (OTA) and is one of the European Space Agency's contributions to the HST program.

Nota, A. (editor); Jedrzejewski, R. (editor); Greenfield, P. (editor); Hack, W. (editor)

1994-01-01

33

Improving the Ability of Image Sensors to Detect Faint Stars and Moving Objects Using Image Deconvolution Techniques  

PubMed Central

In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors. PMID:22294896

Fors, Octavi; Núñez, Jorge; Otazu, Xavier; Prades, Albert; Cardinal, Robert D.

2010-01-01

34

Improving the ability of image sensors to detect faint stars and moving objects using image deconvolution techniques.  

PubMed

In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors. PMID:22294896

Fors, Octavi; Núñez, Jorge; Otazu, Xavier; Prades, Albert; Cardinal, Robert D

2010-01-01

35

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

36

Track-Before-Detect Algorithm for Faint Moving Objects based on Random Sampling and Consensus  

NASA Astrophysics Data System (ADS)

There are many algorithms developed for tracking and detecting faint moving objects in congested backgrounds. One obvious application is detection of targets in images where each pixel corresponds to the received power in a particular location. In our application, a visible imager operated in stare mode observes geostationary objects as fixed, stars as moving and non-geostationary objects as drifting in the field of view. We would like to achieve high sensitivity detection of the drifters. The ability to improve SNR with track-before-detect (TBD) processing, where target information is collected and collated before the detection decision is made, allows respectable performance against dim moving objects. Generally, a TBD algorithm consists of a pre-processing stage that highlights potential targets and a temporal filtering stage. However, the algorithms that have been successfully demonstrated, e.g. Viterbi-based and Bayesian-based, demand formidable processing power and memory. We propose an algorithm that exploits the quasi constant velocity of objects, the predictability of the stellar clutter and the intrinsically low false alarm rate of detecting signature candidates in 3-D, based on an iterative method called "RANdom SAmple Consensus” and one that can run real-time on a typical PC. The technique is tailored for searching objects with small telescopes in stare mode. Our RANSAC-MT (Moving Target) algorithm estimates parameters of a mathematical model (e.g., linear motion) from a set of observed data which contains a significant number of outliers while identifying inliers. In the pre-processing phase, candidate blobs were selected based on morphology and an intensity threshold that would normally generate unacceptable level of false alarms. The RANSAC sampling rejects candidates that conform to the predictable motion of the stars. Data collected with a 17 inch telescope by AFRL/RH and a COTS lens/EM-CCD sensor by the AFRL/RD Satellite Assessment Center is used to assess the performance of the algorithm. In the second application, a visible imager operated in sidereal mode observes geostationary objects as moving, stars as fixed except for field rotation, and non-geostationary objects as drifting. RANSAC-MT is used to detect the drifter. In this set of data, the drifting space object was detected at a distance of 13800 km. The AFRL/RH set of data, collected in the stare mode, contained the signature of two geostationary satellites. The signature of a moving object was simulated and added to the sequence of frames to determine the sensitivity in magnitude. The performance compares well with the more intensive TBD algorithms reported in the literature.

Dao, P.; Rast, R.; Schlaegel, W.; Schmidt, V.; Dentamaro, A.

2014-09-01

37

On the Latitude Variation of Ammonia, Acetylene, and Phosphine Altitude Profiles on Jupiter from HST Faint Object Spectrograph Observations  

Microsoft Academic Search

Ultraviolet spectra in the spectral region from 160 to 230 nm were taken with the Hubble Space Telescope Faint Object Spectrograph in May 1992. We analyze these data to obtain the altitude distribution of ammonia and its variation with latitude from 6°N to 25°N. Ammonia condenses below the 150-mbar level, above which it departs from saturation due to photolysis. Using

S. G. Edgington; S. K. Atreya; L. M. Trafton; J. J. Caldwell; R. F. Beebe; A. A. Simon; R. A. West; C. Barnet

1998-01-01

38

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

39

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

40

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

41

JHK observations of faint standard stars in the Mauna Kea Observatories near-infrared photometric system  

NASA Astrophysics Data System (ADS)

JHK photometry in the Mauna Kea Observatories (MKO) near-infrared system is presented for 115 stars. Of these stars, 79 are United Kingdom Infrared Telescope (UKIRT) standards from Hawarden et al., and 42 are Las Campanas Observatory (LCO, or NICMOS) standards from Persson et al. The average brightness of the sample in all three bandpasses is 11.5 mag, with a range between 10 and 15. The average number of nights each star was observed is 4, and the average of the internal error of the final results is 0.011 mag. These JHK data agree with those reported by other groups to 0.02 mag, for stars in common, which is consistent with the uncertainties. The measurements are used to derive colour transformations between the MKO JHK photometric system and the UKIRT, LCO and Two Micron All-Sky Survey (2MASS) systems. The 2MASS-MKO data scatter by 0.05 mag for redder stars, which is consistent with a dependence on stellar luminosity: the 2MASS J bandpass includes H2O features in dwarfs and the MKO K bandpass includes CO features in giants. We stress that colour transformations derived for stars whose spectra contain only weak features cannot give accurate transformations for objects with strong absorption features within one, but not both, of the filter bandpasses. We find evidence of systematic effects at the 0.02 mag level in the photometry of stars with J < 11 and H,K < 10.5 presented here and in Hawarden et al. This is due to an underestimate of the linearity correction for stars observed with the shortest exposure times; very accurate photometry of stars approaching the saturation limits of infrared detectors which are operated in double-read mode is difficult to obtain. There are indications that four stars in the sample, GSPC S705-D, FS 116 (B216-b7), FS 144 (Ser-EC84) and FS 32 (Feige 108), may be variable. There are 84 stars in the sample presented here that have 11 < J < 15 and 10.5 < H,K < 15, are not suspected to be variable, and have magnitudes with an estimated error <=0.027 mag; 79 of these have an error of <=0.020 mag. These represent the first published high-accuracy JHK stellar photometry in the MKO near-infrared photometric system; we recommend these objects be employed as primary standards for that system.

Leggett, S. K.; Currie, M. J.; Varricatt, W. P.; Hawarden, T. G.; Adamson, A. J.; Buckle, J.; Carroll, T.; Davies, J. K.; Davis, C. J.; Kerr, T. H.; Kuhn, O. P.; Seigar, M. S.; Wold, T.

2006-12-01

42

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

43

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

44

Infrared stationary object acquisition and moving object tracking  

NASA Astrophysics Data System (ADS)

Currently, there is much interest in developing electro-optic and infrared stationary and moving object acquisition and tracking algorithms for Intelligence, Surveillance, and Reconnaissance (ISR) and other applications. Many of the existing EO/IR object acquisition and tracking techniques work well for goodquality images, when object parameters such as size are well-known. However, when dealing with noisy and distorted imagery many techniques are unable to acquire stationary objects nor acquire and track moving objects. This paper will discuss two inter-related problems: (1) stationary object detection and segmentation and (2) moving object acquisition and tracking in a sequence of images that are acquired via an IR sensor mounted on both stationary and moving platforms. 1. A stationary object detection and segmentation algorithm called "Weighted Adaptive Iterative Statistical Threshold (WAIST)" will be described. The WAIST algorithm takes any intensity image and separates object pixels from the background or clutter pixels. Two common image processing techniques are nearest neighbors clustering and statistical thresholding. The WAIST algorithm uses both techniques iteratively, making best use of both techniques. Statistical threshold takes advantage of the fact that object pixels will exist above a threshold based on the statistical properties of the known noise pixels in the image. The nearest neighbor technique takes advantage of the fact that when many neighboring pixels are known object pixels, the pixel in question is more likely to be a object pixel. The WAIST algorithm initializes the nearest neighbor parameters and statistical threshold parameters and adjusts them iteratively to converge to an optimal solution. Each iteration of the algorithm conservatively declares a pixel to be noise as the statistical threshold is raised. This algorithm has proven to segment objects of interest from noisy backgrounds and clutter. Results of the effort are presented. 2. For moving object detection and tracking we identify the challenges that the user faces in this problem; in particular, blind geo-registration of the acquired spatially-warped imagery and their calibration. For moving object acquisition and tracking we present an adaptive signal/image processing approach that utilizes multiple frames of the acquired imagery for geo-registration and sensor calibration. Our method utilizes a cost function to associate detected moving objects in adjacent frames and these results are used to identify the motion track of each moving object in the imaging scene. Results are presented using a ground-based panning IR camera.

Amphay, Sengvieng; Gray, David

2010-10-01

45

Deep 610-MHz Giant Metrewave Radio Telescope observations of the Spitzer extragalactic First Look Survey field - III. The radio properties of Infrared-Faint Radio Sources  

E-print Network

Infrared-Faint Radio Sources (IFRSs) are a class of source which are bright at radio frequencies, but do not appear in deep infrared images. We report the detection of 14 IFRSs within the Spitzer extragalactic First Look Survey field, eight of which are detected near to the limiting magnitude of a deep R-band image of the region, at R ~ 24.5. Sensitive Spitzer Space Telescope images are stacked in order to place upper limits on their mid-infrared flux densities, and using recent 610-MHz and 1.4-GHz observations we find that they have spectral indices which vary between alpha = 0.05 and 1.38, where we define alpha such that S = S_0 nu^(- alpha), and should not be thought of as a single source population. We place constraints on the luminosity and linear size of these sources, and through comparison with well-studied local objects in the 3CRR catalogue demonstrate that they can be modelled as being compact ( 4).

Timothy Garn; Paul Alexander

2008-09-24

46

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

47

The Infrared Evolution of Sakurai's Object  

E-print Network

Infrared spectroscopy and photometry have revealed the remarkable evolution of Sakurai's Object from 1996 to the present. A cooling, carbon-rich photospheric spectrum was observable from 1996 to 1998. Considerable changes occured in 1998 as the continuum reddened due to absorption and emission by newly formed dust located outside the photosphere. In addition, a strong and broad helium 1.083 $\\mu$m P Cygni line developed, signifying the acceleration of an outer envelope of material to speeds as high as 1000 km s$^{-1}$. At the same time the photosphere of the central star remained quiescent. By 1999 the photosphere was virtually completely obscured by the dust and the helium emission line was the only detectable spectral feature remaining in the 1-5 $\\mu$m band. In 2000 emission by dust has become even more dominant, as the envelope continues to expand and cool and the helium line weakens.

T. R. Geballe; A. E. Evans; B. Smalley; V. H. Tyne; S. P. S. Eyres

2001-02-02

48

Hubble Space Telescope Faint Object Spectrograph Spectral Mapping of V2051 Ophiuchi in a Low State  

NASA Astrophysics Data System (ADS)

We report a study of the spectra and structure of the accretion disk of the dwarf nova V2051 Ophiuchi while the star was in an unusual faint brightness state during 1996. The differences between the UV resonant lines and continuum disk surface brightness distributions indicate a vertically extended disk with the emission from these lines arising from the upper atmospheric layers. Distinct emission along the stream trajectory suggests the occurrence of gas stream overflow. Spatially resolved spectra show that the lines are in emission at all disk radii. The Balmer decrement becomes shallower with increasing radius. The FWHMs of the emission lines show differences with respect to that expected for a gas in Keplerian rotation, and the line intensities drop with a radial dependency of I~R-1.78. The uneclipsed light contributes about 5%-10% of the total flux, and its spectrum is dominated by a Balmer jump and strong lines in emission. Broad absorption bands, possibly due to Fe II, are present in the spectra of the disk side farther away from the secondary star, suggesting it arises from absorption by a extended gas region above the disk; the differences between the spectra of the hemisphere farther from and nearer to the secondary star are interpreted in terms of chromospheric emission from a disk with a nonnegligible opening angle (limb-brightening effect). Stellar atmosphere model fits to the extracted white dwarf spectrum lead to a temperature TWD=9500+2900-1900 K and a distance d=67+22-25 pc if the inner disk is opaque or d=92+30-35 pc if the inner disk is optically thin.

Saito, R. K.; Baptista, R.

2006-04-01

49

An Automatic Technique for Finding Faint Moving Objects in Wide Field CCD Images  

NASA Astrophysics Data System (ADS)

The traditional method used to find moving objects in astronomical images is to blink pairs or series of frames after registering them to align the background objects. While this technique is extremely efficient in terms of the low signal-to-noise ratio that the human sight can detect, it proved to be extremely time-, brain- and eyesight-consuming. The wide-field images provided by the large CCD mosaic recently built at IfA cover a field of view of 20 to 30' over 8192(2) pixels. Blinking such images is an enormous task, comparable to that of blinking large photographic plates. However, as the data are available digitally (each image occupying 260Mb of disk space), we are developing a set of computer codes to perform the moving object identification in sets of frames. This poster will describe the techniques we use in order to reach a detection efficiency as good as that of a human blinker; the main steps are to find all the objects in each frame (for which we rely on ``S-Extractor'' (Bertin & Arnouts (1996), A&ASS 117, 393), then identify all the background objects, and finally to search the non-background objects for sources moving in a coherent fashion. We will also describe the results of this method applied to actual data from the 8k CCD mosaic. {This work is being supported, in part, by NSF grant AST 92-21318.}

Hainaut, O. R.; Meech, K. J.

1996-09-01

50

Objects shape determination from a single infrared thermal image  

SciTech Connect

Non-destructive testing by infrared thermography with heat injection has found numerous applications in the industry. However this technique is not always reliable for the inspection of non-planar objects. The goal of the method presented here is to determine the shape of objects present in the field of view from the corresponding single early-recorded infrared digital image, in order to first correct distortions due to inspected object shape and second to detect potential and subsurface defects.

Barker, E.; Maldague, X.; Laurendeau, D. [Univ. Laval, Quebec City, Quebec (Canada)

1994-12-31

51

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

52

Infrared Nebulae Around Young Stellar Objects  

E-print Network

We present a K-band atlas of 106 reflection nebulae, 41 of which are new discoveries. We observed these nebulae with the UH 2.2 m telescope in the course of an imaging survey of 197 objects that were selected to be nearby young Class I sources. K-band images and flux calibrated surface brightness contour plots of each nebula are presented. We found that the near-IR luminosities and physical sizes of the nebulae increase with the bolometric luminosity of the illuminating sources. Only 22 nebulae, about 10% of these candidate Class I sources, have indications of shocked H_2 emission. The great variety of nebulae that we observed prevented us from classifying them based on morphology. However, we note that as the spectral index decreases, the central star is more frequently visible at K-band and the flux from the central star tends to be dominant over the flux from the nebula. For objects that have a higher spectral index, most of the K-band flux is from the reflection nebula, and the central star is less frequently visible. The nebula around IRAS 05450+0019 has a unique morphology, and we speculate that it may be an example of a disk shadow being projected into the surrounding cloud. We present J, H, and K-band images of this object with surface brightness contours, as well as its SED from 1.2 microns to 100 microns.

Michael S. Connelley; Bo Reipurth; Alan T. Tokunaga

2006-11-20

53

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

54

Discrimination of closely spaced objects using infrared sensors  

Microsoft Academic Search

This study uses simulated data from a set of two-band sensors and a set of three-band sensors. There are dozens of warheads and numerous decoys simulated (several decoys for each warhead). For a large part of the scenario, the objects are so close that individual targets cannot be resolved by the sensors, even though a single object's infrared signature could

Karl C. Stengel

1994-01-01

55

Syncope (Fainting)  

MedlinePLUS

... What is syncope? Syncope is temporary loss of consciousness and posture, described as "fainting" or "passing out." ... circulation to the brain and causing loss of consciousness. Typical NMS occurs while standing and is often ...

56

Discrimination of closely spaced objects using infrared sensors  

NASA Astrophysics Data System (ADS)

This study uses simulated data from a set of two-band sensors and a set of three-band sensors. There are dozens of warheads and numerous decoys simulated (several decoys for each warhead). For a large part of the scenario, the objects are so close that individual targets cannot be resolved by the sensors, even though a single object's infrared signature could readily be detected. In those cases, multiple objects are seen as a single object, with the summed intensity of several objects. A BODE discrimination technique, which fits a quadratic and a sinusoid to the infrared time histories, is used to attempt to distinguish the warheads from the decoys. The average coefficients of the curve fit, along with their covariances, are used as features which describe the two object sets (warheads and decoys). Warheads and decoys can be readily distinguished once objects are far enough apart so that no multiple objects are mistaken as single objects. But when a cluster of objects appears as one object on the sensor focal plane, it is apparently impossible to tell whether or not a warhead is present in the cluster.

Stengel, Karl C.

1994-06-01

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

Dual-band infrared capabilities for imaging buried object sites  

SciTech Connect

We discuss dual-band infrared (DBIR) capabilities for imaging buried object sizes. We identify physical features affecting thermal contrast needed to distinguish buried object sites from undisturbed sites or surface clutter. Apart from atmospheric transmission and system performance, these features include: object size, shape, and burial depth; ambient soil, disturbed soil and object site thermal diffusivity differences; surface temperature, emissivity, plant-cover, slope, albedo and roughness variations; weather conditions and measurement times. We use good instrumentation to measure the time-varying temperature differences between buried object sites and undisturbed soil sites. We compare near surface soil temperature differences with radiometric infrared (IR) surface temperature differences recorded at 4.7 {plus_minus} 0.4 {mu}m and at 10.6 {plus_minus} 1.0 {mu}m. By producing selective DBIR image ratio maps, we distinguish temperature-difference patterns from surface emissivity effects. We discuss temperature differences between buried object sites, filled hole site (without buried objects), cleared (undisturbed) soil sites, and grass-covered sites (with and without different types of surface clutter). We compare temperature, emissivity-ratio, visible and near-IR reflectance signatures of surface objects, leafy plants and sod. We discuss the physical aspects of environmental, surface and buried target features affecting interpretation of buried targets, surface objects and natural backgrounds.

Del Grande, N.K.; Durbin, P.F.; Gorvad, M.R.; Perkins, D.E.; Clark, G.A.; Hernandez, J.E.; Sherwood, R.J.

1993-04-02

59

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

60

Detection of new celestial objects at far-infrared wavelengths  

NASA Technical Reports Server (NTRS)

During a high-altitude balloon flight, sources of far-infrared radiation have been detected with apparent fluxes greater than or about equal to 3 pW/sq cm in the spectral band from 50 to 500 microns. While the sources are not uniquely identifiable with any well-known class of celestial objects, two associations should be noted. Many of the objects lie close to local stars; there is also a tendency to cluster around the ecliptic plane. Alternatively, a new class of celestial objects may have been observed.

Friedlander, M. W.; Goebel, J. H.; Joseph, R. D.

1974-01-01

61

SPICES II. Optical and Near-Infrared Identifications of Faint X-Ray Sources from Deep Chandra Observations of Lynx  

E-print Network

We present our first results on field X-ray sources detected in a deep, 184.7 ks observation with the ACIS-I camera on Chandra. The observations target the Lynx field of SPICES, and contains three known X-ray-emitting clusters out to z=1.27. Not including the known clusters, in the 17'x17' ACIS-I field we detect 132 sources in the 0.5-2 keV (soft) X-ray band down to a limiting flux of \\~1.7e-16 erg/cm2/s and 111 sources in the 2-10 keV (hard) X-ray band down to a limiting flux of ~1.3e-15 erg/cm2/s. The combined catalog contains a total of 153 sources, of which 42 are detected only in the soft band and 21 are detected only in the hard band. Confirming previous Chandra results, we find that the fainter sources have harder X-ray spectra, providing a consistent solution to the long-standing `spectral paradox'. From deep optical and near-infrared follow-up data, 77% of the X-ray sources have optical counterparts to I=24 and 71% of the X-ray sources have near-infrared counterparts to K=20. Four of the 24 sources in the near-IR field are associated with extremely red objects (EROs; I-K>4). We have obtained spectroscopic redshifts with the Keck telescopes of 18 of the Lynx Chandra sources. These sources comprise a mix of broad-lined active galaxies, apparently normal galaxies, and two late-type Galactic dwarfs. Intriguingly, one Galactic source is identified with an M7 dwarf exhibiting non-transient, hard X-ray emission. We review non-AGN mechanisms to produce X-ray emission and discuss properties of the Lynx Chandra sample in relation to other samples of X-ray and non-X-ray sources.

Daniel Stern; Paolo Tozzi; S. A. Stanford; Piero Rosati; Brad Holden; Peter Eisenhardt; Richard Elston; K. L. Wu; Andrew Connolly; Hyron Spinrad; Steve Dawson; Arjun Dey; Frederic H. Chaffee

2002-03-22

62

Near-infrared spectroscopy of primitive solar system objects  

NASA Technical Reports Server (NTRS)

We have obtained near-infrared (H and K band at lambda/Delta(lambda) is approximately 480 to 600) spectra of a sample of primitive objects including 2 Centaur objects (2060 Chiron and 5145 Pholus) and 16 P- and D-type asteroids. The spectra were obtained at the United Kingdom Infrared Telescope using the cooled grating spectrometer CGS4, and were used to search for chemically diagnostic vibrational features in these primitive objects. Pholus exhibits broad adsorption features at 2.07 and 2.27 micrometers, as well as a weak feature at 1.72 micrometers. The 1.72- and 2.27-micrometer features are similar to those seen in a laboratory tar sand sample. No distinct absorption features are found in other objects, including Chiron, which displays a spectrally neutral continuum. A comparison of the P- and D-type asteroid spectra with laboratory measurements of organic solids shows no compelling evidence for hydrocarbon overtones seen in terrestrial bituminous tar sands.

Luu, Jane; Jewitt, David; Cloutis, Edward

1994-01-01

63

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

2011-06-01

64

Galaxy evolution and large-scale structure in the far-infrared. II. The IRAS faint source survey  

SciTech Connect

The new IRAS Faint Source Survey data base is used to confirm the conclusion of Hacking et al. (1987) that the 60 micron source counts fainter than about 0.5 Jy lie in excess of predictions based on nonevolving model populations. The existence of an anisotropy between the northern and southern Galactic caps discovered by Rowan-Robinson et al. (1986) and Needham and Rowan-Robinson (1988) is confirmed, and it is found to extend below their sensitivity limit to about 0.3 Jy in 60 micron flux density. The count anisotropy at f(60) greater than 0.3 can be interpreted reasonably as due to the Local Supercluster; however, no one structure accounting for the fainter anisotropy can be easily identified in either optical or far-IR two-dimensional sky distributions. The far-IR galaxy sky distributions are considerably smoother than distributions from the published optical galaxy catalogs. It is likely that structure of the large size discussed here have been discriminated against in earlier studies due to insufficient volume sampling. 105 refs.

Lonsdale, C.J.; Hacking, P.B.; Conrow, T.P.; Rowan-Robinson, M. (JPL, Pasadena, CA (USA) Queen Mary College, London (England))

1990-07-01

65

Galaxy evolution and large-scale structure in the far-infrared. II - The IRAS faint source survey  

NASA Technical Reports Server (NTRS)

The new IRAS Faint Source Survey data base is used to confirm the conclusion of Hacking et al. (1987) that the 60 micron source counts fainter than about 0.5 Jy lie in excess of predictions based on nonevolving model populations. The existence of an anisotropy between the northern and southern Galactic caps discovered by Rowan-Robinson et al. (1986) and Needham and Rowan-Robinson (1988) is confirmed, and it is found to extend below their sensitivity limit to about 0.3 Jy in 60 micron flux density. The count anisotropy at f(60) greater than 0.3 can be interpreted reasonably as due to the Local Supercluster; however, no one structure accounting for the fainter anisotropy can be easily identified in either optical or far-IR two-dimensional sky distributions. The far-IR galaxy sky distributions are considerably smoother than distributions from the published optical galaxy catalogs. It is likely that structure of the large size discussed here have been discriminated against in earlier studies due to insufficient volume sampling.

Lonsdale, Carol J.; Hacking, Perry B.; Conrow, T. P.; Rowan-Robinson, M.

1990-01-01

66

Characteristics analysis of infrared polarization for several typical artificial objects  

NASA Astrophysics Data System (ADS)

It is a difficult point to detect and recognize artificial targets under the disturbance of the complex ground clutter when remote sensing and detection to the earth. Using the different polarization information between artificial object and natural scenery, the ability to distinguish artificial targets from natural scenery can be promoted effectively. On account that the differences of polarization characteristics is an important factor in designing the target recognition method, this paper focuses attention on the application of remote sensing and reconnaissance and makes detailed research on the long wave infrared polarization characteristics of several typical metallic targets, such as aluminum plate and iron plate and the aluminum plate that be coated with black paint or yellow green camouflage. Then, the changing rules of the degree and angle of the long wave infrared polarization changing with the measurement temperature are analyzed and researched. Work of this paper lays the theoretical foundation for the design of remote sensing and detection system based on the infrared polarization information in the future.

Zhang, Yan; Han, Jian-tao; Li, Jicheng; Yang, Wei-ping; Gong, Ting

2014-10-01

67

SPICES II. Optical and Near-Infrared Identifications of Faint X-Ray Sources from Deep Chandra Observations of Lynx  

E-print Network

We present our first results on field X-ray sources detected in a deep, 184.7 ks observation with the ACIS-I camera on Chandra. The observations target the Lynx field of SPICES, and contains three known X-ray-emitting clusters out to z=1.27. Not including the known clusters, in the 17'x17' ACIS-I field we detect 132 sources in the 0.5-2 keV (soft) X-ray band down to a limiting flux of \\~1.7e-16 erg/cm2/s and 111 sources in the 2-10 keV (hard) X-ray band down to a limiting flux of ~1.3e-15 erg/cm2/s. The combined catalog contains a total of 153 sources, of which 42 are detected only in the soft band and 21 are detected only in the hard band. Confirming previous Chandra results, we find that the fainter sources have harder X-ray spectra, providing a consistent solution to the long-standing `spectral paradox'. From deep optical and near-infrared follow-up data, 77% of the X-ray sources have optical counterparts to I=24 and 71% of the X-ray sources have near-infrared counterparts to K=20. Four of the 24 sources i...

Stern, D; Stanford, S A; Rosati, P; Holden, B; Eisenhardt, P; Elston, R; Wu, K L; Connolly, A; Spinrad, H; Dawson, S; Dey, A; Chaffee, F H; Stern, Daniel; Tozzi, Paolo; Rosati, Piero; Holden, Brad; Eisenhardt, Peter; Elston, Richard; Connolly, Andrew; Spinrad, Hyron; Dawson, Steve; Dey, Arjun; Chaffee, Frederic H.

2002-01-01

68

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

69

Rapid response near-infrared spectrophotometric characterization of Near Earth Objects  

NASA Astrophysics Data System (ADS)

Small NEOs are, as a whole, poorly characterized, and we know nothing about the physical properties of the majority of all NEOs. The rate of NEO discoveries is increasing each year, and projects to determine the physical properties of NEOs are lagging behind. NEOs are faint, and generally even fainter by the time that follow-up characterizations can be made days or weeks later. There is a need for a high-throughput, high-efficiency physical characterization strategy in which hundreds of faint NEOs can be characterized each year. Broadband photometry in the near-infrared is sufficiently diagnostic to assign taxonomic types, and hence constrain both the individual and ensemble properties of NEOs. We will present results from our recently initiated program of rapid response near-infrared spectrophotometric characterization of NEOs. We are using UKIRT (on Mauna Kea) and the RATIR instrument on the 1.5m telescope at the San Pedro Martir Observatory (Mexico) to allow us to make observations most nights of the year in robotic/queue mode. This technique is powerful and fast. We have written automated software that allows us to observe NEOs very soon after discovery. Our targets are NEOs that are generally too faint for other characterization techniques. We are on pace to characterize hundreds of NEOs per year.

Mommert, Michael; Trilling, David; Axelrod, Tim; Butler, Nat; Jedicke, Robert; Moskovitz, Nicholas; Pichardo, Barbara; Reyes, Mauricio

2014-11-01

70

Near infrared variability phenomena in young stellar objects  

NASA Astrophysics Data System (ADS)

This thesis presents an observational study of one of the nearest star-forming regions, the ? Ophiuchi cluster, with the goal of characterising stellar activity in young stellar objects. Variability is a common characteristic of pre-main-sequence (PMS) stars and originates from mechanisms related to magnetic fields, accretion discs, and circumstellar extinction. Variability surveys in the infrared (IR) can probe stellar and circumstellar environments and provide information about the dynamics of the on going magnetic and accretion processes. To this end, a large-field (?0.8 deg2), near-IR photometric survey of ? Ophiuchi has been conducted using the Wide Field Camera (WFCAM) at the United Kingdom Infrared Telescope (UKIRT), which monitored the cluster over 14 nights in two consecutive years. Statistical tools, such as the multi-band cross correlation index and the reduced chi-square, were used to disentangle signals of variability from noise. Variability in the near-IR is found to be present in half of the known population of ? Ophiuchi. The behaviours shown are several and can be associated with the existence of spots on the stellar surface, variations in circumstellar extinction, or changes in the geometry of an accretion disc. Furthermore, this thesis explores the feasibility of using photometric variability as a criterion for selection of new low-luminosity candidates of galactic star forming regions down to very low masses. The use of this new selection method could help remove the biases from other techniques. For example, it has the advantage of identifying young sources that do not show IR-excess or have small Hα emission. The use of this relatively new technique should contribute significantly to obtain a full census of the young objects in star formation regions, which remains one of the most important goals of galactic star formation studies. Using variability, a new population of objects has been uncovered, that is believed to be part of the ? Ophiuchi cluster. Using low-resolution ! near-IR spectroscopy, 4 candidate members have been confirmed as PMS stars. Finally, the survey presented in this thesis is the first of its kind in the IR, both in large area surveyed and sensitivity, taking advantage of recent developments in IR astronomical instrumentation. Of future relevance for IR variability studies is the new IR-imager at the Very Large Telesope (VLT), HAWK-I (High-Acuity Wide-field K band Imager), the most advanced IR camera on an 8-meter telescope at the present moment. The instrument was assembled and commissioned during the progress of this thesis, and is presented here, giving emphasis to the contribution of the author to the project.

Alves de Oliveira, Catarina

2008-10-01

71

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

72

Discovery of Associated Absorption Lines in an X-Ray Warm Absorber: Hubble Space Telescope Faint Object Spectrograph Observations of MR 2251-178  

NASA Technical Reports Server (NTRS)

The presence of a 'warm absorber' was first suggested to explain spectral variability in an X-ray spectrum of the radio-quiet quasi-stellar object (QSO) MR 2251-178. A unified picture, in which X-ray warm absorbers and 'intrinsic' UV absorbers are the same, offers the opportunity to probe the nuclear environment of active galactic nuclei. To test this scenario and understand the physical properties of the absorber, we obtained a UV spectrum of MR 2251-178 with the Faint Object Spectrograph on board the Hubble Space Telescope (HST). The HST spectrum clearly shows absorption due to Lyalpha, N v, and C IV, blueshifted by 300 km s(exp -1) from the emission redshift of the QSO. The rarity of both X-ray and UV absorbers in radio-quiet QSOs suggests these absorbers are physically related, if not identical. Assuming the unified scenario, we place constraints on the physical parameters of the absorber and conclude the mass outflow rate is essentially the same as the accretion rate in MR 2251-178.

Monier, Eric M.; Mathur, Smita; Wilkes, Belinda; Elvis, Martin

2001-01-01

73

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

74

Optical and Near-Infrared Calibration of AGN Field Stars: An All-Sky Network of Faint Stars Calibrated on the Landolt System  

NASA Astrophysics Data System (ADS)

We present a total of 12,436 photometric measures of 371 field stars of 26 quasars in the visible (UBVRI) and 22,276 photometric measures of 122 field stars of 13 quasars in the near-infrared (JHK), giving a total of 34,712 measures. Of these, 115 stars in 12 fields are calibrated in both ranges. One further field, Mrk 421, was calibrated, but on close examination all sources were found to be probably nonstellar; thus these results are not included here. The stars observed cover the range from V=11 to V=20 and from K=9 to K=17 and are well distributed around the sky north of declination -30°. This represents the initial sample of an extensive catalog of calibrated fields that will cover the northern sky down to declination -30° and that will cover a wide range of Galactic latitudes. These fields will be useful both for photometry of AGNs in the range from B to K and also as faint calibration standards for large telescopes. The median absolute total error on the photometry, including all known error sources, ranges from 0.008 mag in J to 0.034 mag in B. These errors will be greatly reduced with the addition of further data in the future, although the final precision is fundamentally limited by the photometric errors in the existing lists of calibration stars used to calibrate these data. Based on observations made with Jacobus Kapteyn Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de Los Muchachos and on observations with the IAC-80 and Carlos Sánchez Telescopes operated on the island of Tenerife by the Instituto de Astrofísica de Canarias in the Spanish Observatorio del Teide of the Instituto de Astrofísica de Canarias.

González-Pérez, José Nicolás; Kidger, Mark R.; Martín-Luis, Fabiola

2001-10-01

75

Robust visual tracking of infrared object via sparse representation model  

NASA Astrophysics Data System (ADS)

In this paper, we propose a robust tracking method for infrared object. We introduce the appearance model and the sparse representation in the framework of particle filter to achieve this goal. Representing every candidate image patch as a linear combination of bases in the subspace which is spanned by the target templates is the mechanism behind this method. The natural property, that if the candidate image patch is the target so the coefficient vector must be sparse, can ensure our algorithm successfully. Firstly, the target must be indicated manually in the first frame of the video, then construct the dictionary using the appearance model of the target templates. Secondly, the candidate image patches are selected in following frames and the sparse coefficient vectors of them are calculated via l1-norm minimization algorithm. According to the sparse coefficient vectors the right candidates is determined as the target. Finally, the target templates update dynamically to cope with appearance change in the tracking process. This paper also addresses the problem of scale changing and the rotation of the target occurring in tracking. Theoretic analysis and experimental results show that the proposed algorithm is effective and robust.

Ma, Junkai; Liu, Haibo; Chang, Zheng; Hui, Bin

2014-11-01

76

Discovery of Two New Faint Cataclysmic Variables  

E-print Network

We report on the discovery of two new faint cataclysmic variables. The objects were selected as candidates from two different imaging surveys aimed at the discovery of such faint systems. One survey used color and variability while the other used color and H$_\\alpha$ emission as selection criteria. We present our spectra of the two new variables and discuss their properties. A discussion of the implication of these discoveries on the space density of faint cataclysmic variables is presented.

S. B. Howell; E. Mason; M. Huber; R. Clowes

2002-10-18

77

A Complete Multiwavelength Characterization of Faint Chandra X-Ray Sources Seen in the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey  

NASA Astrophysics Data System (ADS)

We exploit deep combined observations with Spitzer and Chandra of the Spitzer Wide-Area Infrared Extragalactic Survey (SWIRE) in the ELAIS N1 region to investigate the nature of the faint X-ray and IR sources in common, to identify active galactic nucleus (AGN)/starburst diagnostics, and to study the sources of the X-ray and IR cosmic backgrounds (XRB and CIRB). In the 17'×17' area of the Chandra ACIS-I image there are approximately 3400 SWIRE near-IR sources with 4 ? detections in at least two Infrared Array Camera (IRAC) bands and 988 sources detected at 24 ?m with the Multiband Imaging Photometer (MIPS) brighter than S24~=0.1 mJy. Of these, 102 IRAC and 59 MIPS sources have Chandra counterparts, out of a total of 122 X-ray sources present in the area with S0.5-8keV>10-15 ergs cm-2 s-1. We have constructed spectral energy distributions (SEDs) for each source using data from the four IRAC wavebands, Chandra fluxes in the hard (2-8 keV) and soft (0.5-2 keV) X-rays, and optical follow-up data in the wavebands U, g', r', i', Z, and H. We fit a number of spectral templates to the SEDs at optical and IR wavelengths to determine photometric redshifts and spectral categories and also make use of diagnostics based on the X-ray luminosities, hardness ratios, X-ray to IR spectral slopes, and optical morphologies. Although we have spectroscopic redshifts for only a minority of the Chandra sources (10 type 1 QSOs or Seyfert sources and three galaxies), the available SEDs constrain the redshifts for most of the sample sources, which turn out to be typically at 0.5

Franceschini, Alberto; Manners, James; Polletta, Maria del Carmen; Lonsdale, Carol; Gonzalez-Solares, Eduardo; Surace, Jason; Shupe, Dave; Fang, Fan; Xu, C. Kevin; Farrah, Duncan; Berta, Stefano; Rodighiero, Giulia; Perez-Fournon, Ismael; Hatziminaoglou, Evanthia; Smith, Harding E.; Siana, Brian; Rowan-Robinson, Michael; Nandra, Kirpal; Babbedge, Tom; Vaccari, Mattia; Oliver, Seb; Wilkes, Belinda; Owen, Frazer; Padgett, Deborah; Frayer, Dave; Jarrett, Tom; Masci, Frank; Stacey, Gordon; Almaini, Omar; McMahon, Richard; Johnson, Olivia; Lawrence, Andrew; Willott, Chris

2005-05-01

78

Kinematics of faint white dwarfs.  

PubMed

An analysis has been made for solar motion for 128 very faint white dwarfs of color class b or a. While about 40% of these stars may be high-velocity objects, it seems definitely indicated that the luminosity of all of them is considerably lower than that for the "normal" white dwarf of the same color. PMID:16592566

Luyten, W J

1978-10-01

79

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

80

OBJECTIVE: Investigate the use of microbolometer infrared technology for real time imaging at THz frequencies.  

E-print Network

OBJECTIVE: Investigate the use of microbolometer infrared technology for real time imaging at THz microbolometer pixels for sensing at THz frequencies. PHASE 1: During the initial phase of research, a detailed study of real-time THz imaging character- istics of a microbolometer infrared camera will be carried out

81

Search for high-proper motion objects with infrared excess  

NASA Astrophysics Data System (ADS)

The possibility of interstellar migration has been theorized during the past thirty years in the form of 'Dysonships' that, using non-relativistic propulsion systems, are able to colonize the Galaxy in a relatively short time compared to the age of the Galaxy and consequently penetrate inside our solar system too. Observational evidence of this can be potentially obtained using the present state of the art of telescopes and related sensors, by following aimed searches and an expanded SETI protocol. Some transient and unrepeated radio signals recorded during standard SETI observations might be due to the transit of high-proper motion artificial sources of extraterrestrial origin, which are expected to show a very weak optical emission, a strong infrared excess and occasional high-energy bursts in the X and Gamma-ray wavelength ranges. Such artificial sources might show an interest to Earth by sending probes to visit it: such a possibility can be investigated scientifically as well.

Teodorani, Massimo

2014-12-01

82

Design of polarized infrared athermal telephoto objective for penetrating the fog  

NASA Astrophysics Data System (ADS)

Polarized infrared imaging technology is a new detection technique which own the ability of spying through the fog, highlighting the target and recognizing the forgeries, these characters make it a good advantage of increasing the work distance in the fog. Compared to the traditional infrared imaging method, polarized infrared imaging can identify the background and target easily, that is the most distinguishing feature of polarized infrared imaging technology. Owning to the large refractive index of the infrared material, temperature change will bring defocus seriously, athermal infrared objective is necessarily. On the other hand, athermal objective has large total length, and hard to be integrated for their huge volume. However telephoto objective has the character of small volume and short total length. The paper introduce a method of polarized and athermal infrared telephoto objective which can spy the fog. First assign the optical power of the fore group and the rear group on the basis of the principle of telephoto objective, the power of the fore group is positive and the rear group is negative; then distribute the optical power within each group to realize the ability of athermalization, finally computer-aided software is used to correct aberration. In order to prove the feasibility of the scheme, an athermal optical system was designed by virtue of ZEMAX software which works at 8~12 µm, the focal length of 150mm, F number is 2, and total length of the telephoto objective is 120mm. The environment temperature analysis shows that the optical system have stable imaging quality, MTF is close to diffraction limit. This telephoto objective is available for infrared polarized imaging.

Gao, Duorui; Fu, Qiang; Zhao, Zhao; Zhao, Bin; Zhong, Lijun; Zhan, Juntong

2014-11-01

83

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

84

Infrared recombination lines of hydrogen from young objects in the southern Galactic plane  

NASA Technical Reports Server (NTRS)

Near infrared recombination lines of hydrogen are observed in twelve young objects in the southern Galactic plane. The sample includes Herbig-Haro objects and IRAS dark-cloud point sources from the 1987 catalog of Persson and Campbell. In four of the IRAS sources two or three infrared lines are measured, and their intensity ratios are consistent with models of optically thick ionized winds. The intrinsic line shapes, retrieved from maximum-entropy deconvolutions, indicate gas velocities of 100 km/s or more as expected from ionized winds. These sources are apparently embedded pre-main-sequence objects with outflows. They include some of the brightest known YSOs.

Beck, Sara C.; Fischer, Jacqueline; Smith, Howard A.

1991-01-01

85

A simple and efficient object detection method based on saliency measure for infrared radiation image  

NASA Astrophysics Data System (ADS)

Detection of visually salient objects plays an important role in applications such as object segmentation, adaptive compression, object recognition, etc. A simple and computationally efficient method is presented in this paper for detecting visually salient objects in Infrared Radiation images. The proposed method can be divided into three steps. Firstly, the infrared image is pre-processed to increase the contrast between objects and background. Secondly, the spectral residual of the pre-processed image is extracted in the log spectrum, then via corresponding inverse transform and threshold segmentation we can get the rough regions of the salient objects. Finally, we apply a sliding window to acquire the explicit position of the salient objects using the probabilistic interpretation of the semi-local feature contrast which is estimated by comparing the gray level distribution of the object and the surrounding area in the original image. And as we change the size of the sliding window, different size of objects can be found out. In our proposed method, the first two steps combined together to play a role in narrowing the searching region and thus accelerating computation. The third procedure is applied to extract the salient objects. We test our method on abundant amount of Infrared Radiation images, and the results show that our saliency detection based object detection method is effective and robust.

Sun, Zhaolei; Hui, Bin

2014-11-01

86

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

87

The Lack of Torus Emission from BL Lacertae Objects: An Infrared View of Unification with WISE  

NASA Astrophysics Data System (ADS)

We use data from the Wide-Field Infrared Survey Explorer (WISE) to perform a statistical study on the mid-infrared (IR) properties of a large number (~102) of BL Lac objects—low-luminosity active galactic nuclei (AGNs) with a jet beamed toward the Earth. As expected, many BL Lac objects are so highly beamed that their jet synchrotron emission dominates their IR spectral energy distributions. In other BL Lac objects, however, the jet is not strong enough to completely dilute the rest of the AGN emission. We do not see observational signatures of the dusty torus from these weakly beamed BL Lac objects. The lack of observable torus emission is consistent with suggestions that BL Lac objects are fed by radiatively inefficient accretion disks. Implications for the "nature versus nurture" debate for FR I and FR II radio galaxies are briefly discussed. Our study supports the notion that, beyond orientation, accretion rate plays an important role in AGN unification.

Plotkin, Richard M.; Anderson, Scott F.; Brandt, W. N.; Markoff, Sera; Shemmer, Ohad; Wu, Jianfeng

2012-02-01

88

A fast sea-level line extraction and object detection method for infrared sea image  

NASA Astrophysics Data System (ADS)

Usually, there is a distinguishable sea-level line in the infrared sea image, where many possible objects can be found. While relative to varies kinds of objects, the sea-level line can be more easily detected, which makes the sea-level line detection a important step in object detection and recognition in infrared sea images. This paper proposed a fast sea-level line detection method, which estimated pixels of sea-level line through the gray characteristic of neighborhood of them, performed a preliminary sea-level line positioning by line fitting, and verified the results by the linear feature of sea surface edges. Based on the results of sea-level line detection, a fast object candidate detection method was introduced. Experimental results proved that the existing and position of sea-level line can be determined and preliminary object detection can be performed by the proposed method.

Hong, Pu; Lei, Bo; Ren, Tingting; Cai, Yufei

2014-11-01

89

New method for moving objects segmentation based on human vision perception in infrared video  

NASA Astrophysics Data System (ADS)

A new method for moving object segmentation based on human vision perception in infrared video is proposed. In this paper, we introduce a new region growing method to achieve the accurate and complete segmentation of the moving objects. At first, the ideal seeds of every moving object are extracted based on the "hole" effect of temporal difference, respectively. At the next step, on the basis of the consideration that human vision system (HVS) is most sensitive to the local contrast between targets and surrounding, we proposed a metric for "good" infrared target segmentation based on human vision perception. And according to this metric, a search method based on fine and rough adjustment is applied to determine the best growing threshold for every moving object. The segmented mask of every moving object is grown from the relevant seeds with the best growing threshold. At last, the segmented masks of all moving objects are merged into a complete segmented mask. Experimental results show that the proposed method is superior and effective on segmentation of moving object in infrared video.

Min, Chaobo

2013-07-01

90

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

91

Technical considerations for designing low-cost, long-wave infrared objectives  

NASA Astrophysics Data System (ADS)

With the growth of uncooled infrared imaging in the consumer market, the balance between cost implications and performance criteria in the objective lens must be examined carefully. The increased availability of consumer-grade, long-wave infrared cameras is related to a decrease in military usage but it is also due to the decreasing costs of the cameras themselves. This has also driven up demand for low-cost, long-wave objectives that can resolve smaller pixels while maintaining high performance. Smaller pixels are traditionally associated with high cost objectives because of higher resolution requirements but, with careful consideration of all the requirements and proper selection of materials, costs can be moderated. This paper examines the cost/performance trade-off implications associated with optical and mechanical requirements of long-wave infrared objectives. Optical performance, f-number, field of view, distortion, focus range and thermal range all affect the cost of the objective. Because raw lens material cost is often the most expensive item in the construction, selection of the material as well as the shape of the lens while maintaining acceptable performance and cost targets were explored. As a result of these considerations, a low-cost, lightweight, well-performing objective was successfully designed, manufactured and tested.

Desroches, Gerard; Dalzell, Kristy; Robitaille, Blaise

2014-06-01

92

Seeing the Unvierse at redshift one with the AAT and CIRPASS: a multi-object near-infrared spectrograph  

NASA Astrophysics Data System (ADS)

We present preliminary results from the CIRPASS instrument (Parry et al. 2000 SPIE 4008, 1193) -- a near-infrared fiber-fed spectrograph which was successfully commissioned in its multi-object spectroscopy (MOS) mode on the 4-m Anglo Australian Telescope in October 2002. The high resolving power of ? / ? ?FWHM? 5000 enables us to work effectively in the low-background regions between the OH sky lines in the J- and H-bands (1.0-1.7 ? m). CIRPASS-MOS has 150 fibres each of 1.6'' diameter, deployable over a 40'-wide area. A natural project for CIRPASS-MOS is tracing star formation at z ˜ 1 using robust indicators such as H? , redshifted into the near-infrared. We demonstrated this capability in our AAT observations last October, by observing some galaxies from the Calar Alto Deep Imaging Survey (CADIS) selected from a narrow redshift interval at z=0.88 by their [Oriptsize II] 3727 Å line emission observed in extensive Fabry-Perot observations (Hippelein et al. 2003, astro-ph/0302116). The H? is found at ? 1.247 ? m in a very clean (OH line-free) region of the night-sky spectrum, and we were able to detect H? for a number of these galaxies. We demonstrated that CIRPASS achieved its design sensitivity: in a stacked 12-hour exposure we detected lines as faint as 4x 10-17 ergs cm-2 s-1 at 10 ? (for ? vFWHM ˜ 300 km/s). This corresponds to an H? flux at z ˜ 1 equivalent to an unobscured star formation rate of 2 h70-2 Msun yr-1 at z=1 (? M=0.3, ? ? =0.7), comparable to the star formation rate of the Milky Way today. We also successfully targeted a number of galaxies with photometric redshifts z ˜ 1, and broad-band colours indicating star formation. We are currently installing a 2kx 2k detector on CIRPASS, which will double the wavelength coverage to 2100 Å , and hence our ability to successfully target photometrically-selected galaxies over a range of redshifts will be greatly increased.

Parry, I. R.; Dalton, G. B.; Doherty, M.; Sharp, R. G.; Dean, A. J.; Bunker, A. J.; Lewis, I.; MacDonald, E.; Wolf, C.; Hippelein, H.; Meisenheimer, K.; Moustakas, L. A.

2003-05-01

93

A bio-inspired infrared imager with on chip object computation  

NASA Astrophysics Data System (ADS)

This paper discusses a Biologically Inspired Shortwave Infrared (SWIR) imager that performs on chip object detection using temporal and spatial processing embedded in the imager's readout integrated circuit (ROIC). The sensor circuit is designed to detect pixel level intensity changes and correlate the change with nearby intensity changes using multiple thresholding criteria to output object exceedances. The sensor is capable of automatically outputting both normal video and also a reduced data set of binarized exceedances. Therefore this SWIR sensor with onboard temporal spatial sensing should be well suited to both manned and unmanned sensing scenarios which could benefit from automated object detection and reduced data sets.

McCarley, Paul L.; Caulfield, John T.

2014-06-01

94

Spectroscopy of Stellar Jets, Outflows, and Young Stellar Objects with the Infrared Space Observatory  

E-print Network

The Infrared Space Observatory (ISO) was an extremely successful european space mission that gave us an unparallel view of the Universe in the infrared, and provided us with hundreds of observations of star forming regions and bipolar outflows. Three of the instrument teams, in charge of the infrared camera (CAM) and the two spectrometers at short and long wavelengths (SWS and LWS respectively), used a significant fraction of their guarantee time to study YSOs and outflows spectroscopically. In here, I will briefly review some of their main findings, particularly the detection of water, H2 rotational emission lines and the presence of other complex molecules. I will present new spectroscopic results on HH 1-2, HH 7-11 and Cep E, and their sources. And finally, I will discuss some of the general trends derived from these observations and their relevance in understanding the emission from these objects using J and C shock models.

Alberto Noriega-Crespo

2001-01-04

95

Optical Design of an Infrared Multi-Object Spectrometer Utilizing a Free-Form Optical Surface  

Microsoft Academic Search

The optical design for an InfraRed Multi-Object Spectrometer (IRMOS) is presented along with fabrication and metrology results. IRMOS presents a challenging set of design problems through the use of a micro-mirror array (a Texas Instruments DMD) and a multi-stage optical layout. This instrument is unique in that it is one of the first principal investigator-class astronomical instruments that make use

Robert S. Winsor; Raymond G. Ohl; Joseph A. Connelly; John W. MacKenty

96

Optical and Near Infrared Study of the Cepheus E outflow, a very low excitation object  

E-print Network

We present images and spectra of the Cepheus E (Cep E) region at both optical and infrared wavelengths. Only the brightest region of the southern lobe of the Cep E outflow reveals optical emission, suggesting that the extinction close to the outflow source plays an important r\\^ole in the observed difference between the optical and IR morphologies. Cep E is a unique object since it provides a link between the spectroscopic properties of the optical Herbig-Haro (HH) objects and those of deeply embedded outflows.

S. Ayala; A. Noriega-Crespo; P. M. Garnavich; S. Curiel; A. C. Raga; K. H. Bohm; J. Raymond

2000-04-20

97

THE LACK OF TORUS EMISSION FROM BL LACERTAE OBJECTS: AN INFRARED VIEW OF UNIFICATION WITH WISE  

SciTech Connect

We use data from the Wide-Field Infrared Survey Explorer (WISE) to perform a statistical study on the mid-infrared (IR) properties of a large number ({approx}10{sup 2}) of BL Lac objects-low-luminosity active galactic nuclei (AGNs) with a jet beamed toward the Earth. As expected, many BL Lac objects are so highly beamed that their jet synchrotron emission dominates their IR spectral energy distributions. In other BL Lac objects, however, the jet is not strong enough to completely dilute the rest of the AGN emission. We do not see observational signatures of the dusty torus from these weakly beamed BL Lac objects. The lack of observable torus emission is consistent with suggestions that BL Lac objects are fed by radiatively inefficient accretion disks. Implications for the 'nature versus nurture' debate for FR I and FR II radio galaxies are briefly discussed. Our study supports the notion that, beyond orientation, accretion rate plays an important role in AGN unification.

Plotkin, Richard M.; Markoff, Sera [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands); Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Brandt, W. N.; Wu Jianfeng [Department of Astronomy and Astrophysics, Pennsylvania Sate University, 525 Davey Laboratory, University Park, PA 16802 (United States); Shemmer, Ohad, E-mail: r.m.plotkin@uva.nl [Department of Physics, University of North Texas, Denton, TX 76203 (United States)

2012-02-15

98

The Lack of Torus Emission from BL Lacertae Objects: An Infrared View of Unification with WISE  

E-print Network

We use data from the Wide-Field Infrared Survey Explorer (WISE) to perform a statistical study on the mid-infrared (IR) properties of a large number ($\\sim10^2$) of BL Lac objects --- low-luminosity Active Galactic Nuclei (AGN) with a jet beamed toward the Earth. As expected, many BL Lac objects are so highly beamed that their jet synchrotron emission dominates their IR spectral energy distributions. In other BL Lac objects, however, the jet is not strong enough to completely dilute the rest of the AGN emission. We do not see observational signatures of the dusty torus from these weakly beamed BL Lac objects. The lack of observable torus emission is consistent with suggestions that BL Lac objects are fed by radiatively inefficient accretion disks. Implications for the "nature vs. nurture" debate for FR I and FR II radio galaxies are briefly discussed. Our study supports the notion that, beyond orientation, accretion rate plays an important role in AGN unification.

Plotkin, Richard M; Brandt, W N; Markoff, Sera; Shemmer, Ohad; Wu, Jianfeng

2011-01-01

99

IRIS2: a working infrared multi-object spectrograph and camera  

NASA Astrophysics Data System (ADS)

IRIS2 is a near-infrared imager and spectrograph based on a HAWAII1 HgCdTe detector. It provides wide-field (7.7"×7.7") imaging capabilities at 0.4486"/pixel sampling, long-slit spectroscopy at R~2400 in each of the J, H and K passbands, and the ability to do multi-object spectroscopy in up to three masks. These multi-slit masks are laser cut, and have been manufactured for both traditional multiple slit work (~20-40 objects in a 3"×7.4" field-of-view), multiple slit work in narrow-band filters (~100 objects in a 5"×7.4" field-of-view), and micro-hole spectroscopy in narrow-band filters allowing the observation of ?200 objects in a 5"×7.4" field.

Tinney, Chris G.; Ryder, Stuart D.; Ellis, Simon C.; Churilov, Vladimir; Dawson, John; Smith, Greg A.; Waller, Lew; Whittard, John D.; Haynes, Roger; Lankshear, Allan; Barton, John R.; Evans, C. J.; Shortridge, Keith; Farrell, Tony; Bailey, Jeremy

2004-09-01

100

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

101

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

102

Machine measurements of the objective-prism spectra of faint galaxies. I - Plate measurements and initial data reduction. II - Interactive redshift measurements  

NASA Astrophysics Data System (ADS)

A high-speed microdensitometer known as COSMOS, which is capable of measuring UK Schmidt Telescope (UKST) objective-prism plates, is described. Emphasis is placed on its ability to extract digitized spectra. It is noted that COSMOS meets measuring machine requirements in that it can measure entire spectra at a resolution such that pixel-by-pixel intensity conversion can be performed before any averaging or summation. Parameterized data obtained by COSMOS is processed via a system known as HAGGIS, which is instrumental in both the detection and selection of images. Applications of these software-extracted spectra include the automated detection of quasars and the classification of stellar spectra.

Cooke, J. A.; Beard, S. M.; Emerson, D.; Kelly, B. D.; MacGillivray, H. T.

1986-03-01

103

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

2011-08-01

104

A systematic survey for eruptive young stellar objects using mid-infrared photometry  

NASA Astrophysics Data System (ADS)

Accretion in young stellar objects (YSOs) is at least partially episodic, i.e. periods with high accretion rates (`bursts') are interspersed by quiescent phases. These bursts manifest themselves as eruptive variability. Here we present a systematic survey for eruptive YSOs aiming to constrain the frequency of accretion bursts. We compare mid-infrared photometry from Spitzer and WISE separated by ˜5 yr for two samples of YSOs, in nearby star-forming regions and in the Galactic plane, each comprising about 4000 young sources. All objects for which the brightness at 3.6 and 4.5 ?m is increased by at least 1 mag between the two epochs may be eruptive variables and burst candidates. For these objects, we carry out follow-up observations in the near-infrared. We discover two new eruptive variables in the Galactic plane which could be FU Ori-type objects, with K-band amplitudes of more than 1.5 mag. One object known to undergo an accretion burst, V2492 Cyg, is recovered by our search as well. In addition, the young star ISO-Oph-50, previously suspected to be an eruptive object, is found to be better explained by a disc with varying circumstellar obscuration. In total, the number of burst events in a sample of 4000 YSOs is 1-4. Assuming that all YSOs undergo episodic accretion, this constraint can be used to show that phases of strong accretion (>10-6 M? yr-1) occur in intervals of about 104 yr, most likely between 5000 and 50 000 yr. This is consistent with the dynamical time-scales for outflows, but not with the separations of emission knots in outflows, indicating that episodic accretion could either trigger or stop collimated large-scale outflows.

Scholz, Alexander; Froebrich, Dirk; Wood, Kenneth

2013-04-01

105

Passive signatures concealed objects recorded by multispectral and hyperspectral systems in visible, infrared and terahertz range  

NASA Astrophysics Data System (ADS)

Risks to the safety of public zones (generally available for people) are related mainly to the presence of hidden dangerous objects (such as knives, guns, bombs etc.) and their usage. Modern system for the monitoring of such zones attempt to detect dangerous tools using multispectral cameras working in different spectral ranges: the visible radiation, near, medium and long range infrared and recently also in terahertz range. In order to develop methods and algorithms to detect hidden objects it is necessary to determine the thermal signatures of such objects of interest. The laboratory measurements were conducted to determine the thermal signatures of dangerous tools hidden under various clothes in different ambient conditions. Cameras used for measurements were working in spectral range 0.6-12.5 µm. An infrared imaging Fourier transform spectroradiometer was also used, working in spectral range 7.7-11.7 µm. Analysis of registered thermograms and hyperspectral datacubes has yielded the thermal signatures for: two types of guns, two types of knives and home-made explosive bombs. The determined thermal signatures will be used in the development of method and algorithms of image analysis implemented in proposed monitoring systems.

Kastek, Mariusz; Kowalski, Marcin; Polakowski, Henryk; Lagueux, Philippe; Gagnon, Marc-André

2014-06-01

106

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

107

Objective assessment of biomagnetic devices and alternative clinical therapies using infrared thermal imaging  

NASA Astrophysics Data System (ADS)

The overwhelming introduction of magnetic devices and other alternative therapies into the health care market prompts the need for objective evaluation of these techniques through the use of infrared thermal imaging. Many of these therapies are reported to promote the stimulation of blood flow or the relief of pain conditions. Infrared imaging is an efficient tool to assess such changes in the physiological state. Therefore, a thermal imager can help document and substantiate whether these therapies are in fact providing an effective change to the local circulation. Thermal images may also indicate whether the change is temporary or sustained. As a specific case example, preliminary findings will be presented concerning the use of magnets and the effect they have on peripheral circulation. This will include a discussion of the recommended protocols for this type of infrared testing. This test model can be applied to the evaluation of other devices and therapeutic procedures which are reputed to affect circulation such as electro acupuncture, orthopedic footwear and topical ointments designed to relieve pain or inflammation.

Rockley, Graham J.

2001-03-01

108

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

109

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

110

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

111

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

112

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

113

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

114

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

115

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

116

Deep infrared galaxies  

NASA Technical Reports Server (NTRS)

High signal-to-noise ratio optical spectra of 17 infrared-bright emission-line galaxies near the north ecliptic pole are presented. Reddening-corrected line ratios forbidden O III 5007/H-beta, N II 6583/H-alpha, S II (6716 + 6731)/H-alpha, and O I 6300/H-alpha are used to discriminate between candidate energy generation mechanisms in each galaxy. These criteria have frequently been applied to optically selected samples of galaxies in the past, but this is the first time they have been applied to a set of faint flux-limited infrared-selected objects. The analysis indicates the sample contains seven starburst galaxies and three (AGN). However, seven galaxies in the present sample elude the classification scheme based on these line ratios. It is concluded that a two-component (starburst plus AGN) model for energy generation is inadequate for infrared galaxies.

Ashby, Matthew; Houck, J. R.; Hacking, Perry B.

1992-01-01

117

Objective assessment of skin rejuvenation using near-infrared 1064-nm neodymium: YAG laser in Asians  

PubMed Central

Background We reported previously that near-infrared (NIR) irradiation provides long-lasting stimulation of elastin, and is efficient for skin rejuvenation. Many studies have indicated the efficacy of various types of laser, but did not include sufficiently objective evaluation. Therefore, we evaluated the efficacy of NIR laser treatment not only subjectively but also objectively. Methods Fifty Japanese patients were treated with a NIR 1064-nm neodymium: YAG laser. Objective computer assessments were performed by Canfield VISIA Complexion Analysis for improvement of dilated pores, skin texture, and wrinkles. The volunteers then provided subjective assessments. Histological evaluations of elastin were performed by Victoria blue staining up to 90 days post-treatment in four Japanese volunteers. Results Mean pretreatment percentiles of dilated pores, skin texture, and wrinkles were 51.08 ± 24.82, 54.7 ± 26.33, and 58.02 ± 28.61, respectively. Mean post-treatment percentiles of dilated pores, skin texture, and wrinkles were 53.58 ± 23.89, 58.58 ± 24.44, and 62.2 ± 25.39, respectively. All objective computer assessments evaluated by percentiles in dilated pores, skin texture, and wrinkles showed significant improvement after NIR laser treatment. Ninety-six percent, 100%, and 98% of volunteers reported satisfaction with the improvement of dilated pores, skin texture, and wrinkles, respectively. NIR laser treatment appeared to increase the amount of elastin at day 30, which then decreased slightly but was still elevated at day 90 compared with nonirradiated controls on day 0. Thickening of the epidermis was detected on day 30, and epidermal smoothness persisted for up to 90 days. No treatment-related adverse events were observed. Conclusions NIR irradiation increased elastin in the dermis, and achieved skin rejuvenation. The results indicated that NIR irradiation provides safe and effective long-term stimulation of elastin, which is beneficial for improving dilated pores, skin texture, and wrinkles. PMID:21833163

Tanaka, Yohei; Matsuo, Kiyoshi; Yuzuriha, Shunsuke

2011-01-01

118

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

119

Detecting the first objects in the mid-infrared with the Next Generation Space Telescope  

NASA Astrophysics Data System (ADS)

We calculate the expected mid-infrared (MIR) molecular hydrogen line emission from the first objects in the Universe. As a result of their low masses, the stellar feedback from massive stars is able to blow away their gas content and collect it into a cooling shell where H2 rapidly forms and IR roto-vibrational (as for example the rest-frame 2.12?m) lines carry away a large fraction (up to 10 per cent) of the explosion energy. The fluxes from these sources are in the range 10-21-10-17ergs-1cm-2. The highest number counts are expected in the 20-?m band, where about 105 sources deg-2 are predicted at the limiting flux of 3×10-18ergs-1cm-2. Among the planned observational facilities, we find that the best detection perspectives are offered by the Next Generation Space Telescope (NGST), which should be able to reveal about 200 first objects in one hour observation time at its limiting flux in the above band. Therefore, mid-IR instruments appear to represent perfect tools to trace star formation and stellar feedback in the high (z>~5) redshift Universe.

Ciardi, Benedetta; Ferrara, Andrea

2001-06-01

120

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

121

Young Stellar Object VARiability (YSOVAR): Long Timescale Variations in the Mid-infrared  

NASA Astrophysics Data System (ADS)

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (3.6 and 4.5 ?m) time series photometry of the Orion Nebula Cluster plus smaller footprints in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. We present the data collection and reduction for the Spitzer and ancillary data, and define the "standard sample" on which we calculate statistics, consisting of fast cadence data, with epochs roughly twice per day for ~40 days. We also define a "standard sample of members" consisting of all the IR-selected members and X-ray-selected members. We characterize the standard sample in terms of other properties, such as spectral energy distribution shape. We use three mechanisms to identify variables in the fast cadence data—the Stetson index, a ?2 fit to a flat light curve, and significant periodicity. We also identified variables on the longest timescales possible of six to seven years by comparing measurements taken early in the Spitzer mission with the mean from our YSOVAR campaign. The fraction of members in each cluster that are variable on these longest timescales is a function of the ratio of Class I/total members in each cluster, such that clusters with a higher fraction of Class I objects also have a higher fraction of long-term variables. For objects with a YSOVAR-determined period and a [3.6]-[8] color, we find that a star with a longer period is more likely than those with shorter periods to have an IR excess. We do not find any evidence for variability that causes [3.6]-[4.5] excesses to appear or vanish within our data set; out of members and field objects combined, at most 0.02% may have transient IR excesses.

Rebull, L. M.; Cody, A. M.; Covey, K. R.; Günther, H. M.; Hillenbrand, L. A.; Plavchan, P.; Poppenhaeger, K.; Stauffer, J. R.; Wolk, S. J.; Gutermuth, R.; Morales-Calderón, M.; Song, I.; Barrado, D.; Bayo, A.; James, D.; Hora, J. L.; Vrba, F. J.; Alves de Oliveira, C.; Bouvier, J.; Carey, S. J.; Carpenter, J. M.; Favata, F.; Flaherty, K.; Forbrich, J.; Hernandez, J.; McCaughrean, M. J.; Megeath, S. T.; Micela, G.; Smith, H. A.; Terebey, S.; Turner, N.; Allen, L.; Ardila, D.; Bouy, H.; Guieu, S.

2014-11-01

122

MOSFIRE, the multi-object spectrometer for infra-red exploration at the Keck Observatory  

NASA Astrophysics Data System (ADS)

This paper describes the as-built performance of MOSFIRE, the multi-object spectrometer and imager for the Cassegrain focus of the 10-m Keck 1 telescope. MOSFIRE provides near-infrared (0.97 to 2.41 ?m) multi-object spectroscopy over a 6.1' x 6.1' field of view with a resolving power of R~3,500 for a 0.7" (0.508 mm) slit (2.9 pixels in the dispersion direction), or imaging over a field of view of ~6.9' diameter with ~0.18" per pixel sampling. A single diffraction grating can be set at two fixed angles, and order-sorting filters provide spectra that cover the K, H, J or Y bands by selecting 3rd, 4th, 5th or 6th order respectively. A folding flat following the field lens is equipped with piezo transducers to provide tip/tilt control for flexure compensation at the <0.1 pixel level. Instead of fabricated focal plane masks requiring frequent cryo-cycling of the instrument, MOSFIRE is equipped with a cryogenic Configurable Slit Unit (CSU) developed in collaboration with the Swiss Center for Electronics and Microtechnology (CSEM). Under remote control the CSU can form masks containing up to 46 slits with ~0.007-0.014" precision. Reconfiguration time is < 6 minutes. Slits are formed by moving opposable bars from both sides of the focal plane. An individual slit has a length of 7.0" but bar positions can be aligned to make longer slits in increments of 7.5". When masking bars are retracted from the field of view and the grating is changed to a mirror, MOSFIRE becomes a wide-field imager. The detector is a 2K x 2K H2-RG HgCdTe array from Teledyne Imaging Sensors with low dark current and low noise. Results from integration and commissioning are presented.

McLean, Ian S.; Steidel, Charles C.; Epps, Harland W.; Konidaris, Nicholas; Matthews, Keith Y.; Adkins, Sean; Aliado, Theodore; Brims, George; Canfield, John M.; Cromer, John L.; Fucik, Jason; Kulas, Kristin; Mace, Greg; Magnone, Ken; Rodriguez, Hector; Rudie, Gwen; Trainor, Ryan; Wang, Eric; Weber, Bob; Weiss, Jason

2012-09-01

123

Mid-Infrared Size Survey of Young Stellar Objects: Description of Keck Segment-Tilting Experiment and Basic Results  

NASA Astrophysics Data System (ADS)

The mid-infrared properties of pre-planetary disks are sensitive to the temperature and flaring profiles of disks for the regions where planet formation is expected to occur. In order to constrain theories of planet formation, we have carried out a mid-infrared (? = 10.7 ?m) size survey of young stellar objects using the segmented Keck telescope in a novel configuration. We introduced a customized pattern of tilts to individual mirror segments to allow efficient sparse-aperture interferometry, allowing full aperture synthesis imaging with higher calibration precision than traditional imaging. In contrast to previous surveys on smaller telescopes and with poorer calibration precision, we find that most objects in our sample are partially resolved. Here, we present the main observational results of our survey of five embedded massive protostars, 25 Herbig Ae/Be stars, 3 T Tauri stars, 1 FU Ori system, and five emission-line objects of uncertain classification. The observed mid-infrared sizes do not obey the size-luminosity relation found at near-infrared wavelengths and a companion paper will provide further modeling analysis of this sample. In addition, we report imaging results for a few of the most resolved objects, including complex emission around embedded massive protostars, the photoevaporating circumbinary disk around MWC 361A, and the subarcsecond binaries T Tau, FU Ori, and MWC 1080.

Monnier, J. D.; Tuthill, P. G.; Ireland, M.; Cohen, R.; Tannirkulam, A.; Perrin, M. D.

2009-07-01

124

Detecting Moving Objects in Airborne Forward Looking Infra-Red Sequences Alexander Strehl and J. K. Aggarwal  

E-print Network

In this paper we propose a system that detects indepen- dently moving objects (IMOs) in forward looking infra of our robust system into a comprehensive au- tomatic target recognition (ATR) and action classification system. 1 Introduction 1.1 Motivation Forward looking infra-red (FLIR) images are frequently used

Strehl, Alexander

125

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

126

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

127

Young Stellar Object Search toward the Boundary of the Central Molecular Zone with Near-infrared Polarimetry  

NASA Astrophysics Data System (ADS)

We have carried out near-infrared polarimetry toward the boundary of the Central Molecular Zone, in the field of (-1.°4 <~ l <~ -0.°3 and 1.°0 <~ l <~ 2.°9, |b| <~ 0.°1), using the near-infrared polarimetric camera SIRPOL on the 1.4 m Infrared Survey Facility telescope. We have selected 112 intrinsically polarized sources on the basis of the estimate of interstellar polarization on Stokes Q/I - U/I planes. The selected sources are brighter than KS = 14.5 mag and have polarimetric uncertainty ?P < 1%. Ten of these distinctive polarized sources are fit well with spectral energy distributions of young stellar objects when using the photometry in the archive of the Spitzer Space Telescope mid-infrared data. However, many sources have spectral energy distributions of normal stars suffering from heavy interstellar extinction; these might be stars behind dark clouds. Due to the small number of distinctive polarized sources and candidates of young stellar objects, we cannot judge if they are declining in number outside the Central Molecular Zone. Many massive candidates for young stellar objects in the literature have only small intrinsic polarization. This might suggest that their masses are 4-15 M ?, whose intrinsic polarization has been expected to be small.

Yoshikawa, Tatsuhito; Nishiyama, Shogo; Tamura, Motohide; Kwon, Jungmi; Nagata, Tetsuya

2014-08-01

128

Development of an integral field unit for a near-infrared multi-object imaging spectrograph SWIMS  

NASA Astrophysics Data System (ADS)

We are developing an integral field unit (IFU) for a near-infrared multi-object imaging spectrograph SWIMS (Simultaneous-color Wide-field Infrared Multi-object Spectrograph). SWIMS is an instrument for the 6.5m telescope of the University of Tokyo Atacama Observatory (TAO) project on the summit of Co. Chajnantor (altitude of 5,640m) in northern Chile. Most of near infrared integral field spectrographs (IFSs) on 8-10m class telescopes are used with adaptive optics and have fine spatial sampling. Compared with them, SWIMS IFU has higher sensitivity for extended objects because it has coarser spatial sampling optimized for seeing-limit observations. We have investigated the feasible optical design, and found a possible layout whose field of view is about 14 x 10 arcsec2 with 0.4 arcsec slice width. All IFU mirror arrays will be made of aluminum alloy to match the thermal expansion with support structures, as they are placed in a cryogenic environment. They will be fabricated monolithically with high precision machining to reduce alignment process. We have carried out a fabrication test of a spherical surface and confirmed that surface roughness and surface figure error are enough low for near-infrared light. As a next step, fabrication of a prototype mirror array with 3 reflective surfaces is planned. In this paper, we will show our project outline, the IFU optical design and the results of prototyping works.

Ozaki, Shinobu; Kitagawa, Yutaro; Motohara, Kentaro; Konishi, Masahiro; Takahashi, Hidenori; Yoshikawa, Tomohiro; Tateuchi, Ken; Kato, Natsuko

2012-09-01

129

A near-infrared spectroscopic survey of massive jets towards extended green objects  

NASA Astrophysics Data System (ADS)

Context. Protostellar jets and outflows are the main outcome of the star formation process, and their analysis can provide us with major clues about the ejection and accretion history of young stellar objects (YSOs). Aims: We aim at deriving the main physical properties of massive jets from near-infrared (NIR) observations, comparing them to those of a large sample of jets from low-mass YSOs, and relating them to the main features of their driving sources. Methods: We present a NIR imaging (H2 and Ks) and low-resolution spectroscopic (0.95-2.50 ?m) survey of 18 massive jets towards GLIMPSE extended green objects (EGOs), driven by intermediate- and high-mass YSOs, which have bolometric luminosities (Lbol) between 4 × 102 and 1.3 × 105 L?. Results: As in low-mass jets, H2 is the primary NIR coolant, detected in all the analysed flows, whereas the most important ionic tracer is [Fe ii], detected in half of the sampled jets. Our analysis indicates that the emission lines originate from shocks at high temperatures and densities. No fluorescent emission is detected along the flows, regardless of the source bolometric luminosity. On average, the physical parameters of these massive jets (i.e. visual extinction, temperature, column density, mass, and luminosity) have higher values than those measured in their low-mass counterparts. The morphology of the H2 flows is varied, mostly depending on the complex, dynamic, and inhomogeneous environment in which these massive jets form and propagate. All flows and jets in our sample are collimated, showing large precession angles. Additionally, the presence of both knots and jets suggests that the ejection process is continuous with burst episodes, as in low-mass YSOs. We compare the flow H2 luminosity with the source bolometric luminosity confirming the tight correlation between these two quantities. Five sources, however, display a lower LH2/Lbol efficiency, which might be related to YSO evolution. Most important, the inferred LH2 vs. Lbol relationship agrees well with the correlation between the momentum flux of the CO outflows and the bolometric luminosities of high-mass YSOs indicating that outflows from high-mass YSOs are momentum driven, as are their low-mass counterparts. We also derive a less stringent correlation between the inferred mass of the H2 flows and Lbol of the YSOs, indicating that the mass of the flow depends on the driving source mass. Conclusions: By comparing the physical properties of jets in the NIR, a continuity from low- to high-mass jets is identified. Massive jets appear as a scaled-up version of their low-mass counterparts in terms of their physical parameters and origin. Nevertheless, there are consistent differences such as a more variegated morphology and, on average, stronger shock conditions, which are likely due to the different environment in which high-mass stars form. Based on observations collected at the European Southern Observatory La Silla, Chile, 080.C-0573(A), 083.C-0846(A).Appendices are available in electronic form at http://www.aanda.org

Caratti o Garatti, A.; Stecklum, B.; Linz, H.; Garcia Lopez, R.; Sanna, A.

2015-01-01

130

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

131

Frontal Lobe Activation during Object Permanence: Data from Near-Infrared Spectroscopy  

Microsoft Academic Search

The ability to create and hold a mental schema of an object is one of the milestones in cognitive development. Developmental scientists have named the behavioral manifestation of this competence object permanence. Convergent evidence indicates that frontal lobe maturation plays a critical role in the display of object permanence, but methodological and ethical constrains have made it difficult to collect

Abigail A. Baird; Jerome Kagan; Thomas Gaudette; Kathryn A. Walz; Natalie Hershlag; David A. Boas

2002-01-01

132

Infrared heterodyne spectroscopy. [for observation of thermal emission from astrophysical objects  

NASA Technical Reports Server (NTRS)

Infrared heterodyne spectroscopy is an extremely useful tool for Doppler-limited studies of atomic and molecular lines in diverse astrophysical regions. The current state of the art is reviewed, and the analysis of CO2 lines in the atmosphere of Mars is outlined. Doppler-limited observations have enabled the discovery of natural laser emission in the mesosphere of Mars and the discovery of failure of local thermodynamic equilibrium near the surface of Mars.

Mumma, M. J.; Kostiuk, T.; Buhl, D.; Chin, G.; Zipoy, D.

1982-01-01

133

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

134

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

135

Design and status of a near-infrared multi-object spectrograph for the TAO 6.5-m Telescope  

NASA Astrophysics Data System (ADS)

We describe the design and current status of a near-infrared multi-object spectrograph for the University of Tokyo Atacama Observatory (TAO) project, which is to construct a 6.5m infrared telescope on the summit of Co. Chajnantor (altitude of 5,460m) in the northern Chile. The instrument, named SWIMS (Simultaneous-color Wide-field Infrared Multi-object Spectrograph), covers a wavelength range from 0.9 to 2.5 ?m with a field of view of 9.6 in diameter using 4096 × 4096 pixels with a pixel scale of 0.13 pixel-1. It has two observation modes: a wide-field imager and a multi-object spectrograph (MOS). The MOS mode adopts cooled multi-slit masks with 30 slits at a maximum, and achieves a spectral resolution of ?/??~ 1000. Up to 20 masks can be installed in a mask storage dewar. In both modes, two wavelength ranges of 0.9-1.4 ?m and 1.4-2.5 ?m are observed simultaneously with a dichroic mirror placed in the collimated beam. This will provide us data covering the wide spectral range under same conditions such as weather, telescope pointing, and so on. Such data are important not only for redshift surveys of distant galaxies but also for rapidly time-variable events such as gamma-ray bursts. As SWIMS is expected to be completed before the construction of the 6.5m telescope, we plan to carry out performance verification and early scientific observations on the Subaru Telescope at Hawaii.

Konishi, Masahiro; Motohara, Kentaro; Doi, Mamoru; Sako, Shigeyuki; Toshikawa, Koji; Mitani, Natsuko; Aoki, Tsutomu; Handa, Toshihiro; Ita, Yoshifusa; Kato, Daisuke; Kawara, Kimiaki; Kohno, Kotaro; Koshida, Shintaro; Minezaki, Takeo; Miyata, Takashi; Soyano, Takao; Tanabe, Toshihiko; Tanaka, Masuo; Tarusawa, Ken'ichi; Yoshii, Yuzuru

2010-07-01

136

The High $\\mathrm{A_V}$ Quasar Survey: Reddened Quasi Stellar Objects selected from optical/near-infrared photometry - II  

E-print Network

Quasi Stellar Objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the SDSS. To overcome this bias against red QSOs, we employ a combined optical and near-infrared color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by photometry from the Wide-field Infrared Survey Explorer (WISE). In our sample of 159 candidates, 154 (97 %) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify 9 such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems towards 30 QSOs, two of which are consistent with the...

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

2014-01-01

137

Object detection utilizing a linear retrieval algorithm for thermal infrared imagery  

SciTech Connect

Thermal infrared (TIR) spectroscopy and remote sensing have been proven to be extremely valuable tools for mineralogic discrimination. One technique for sub-pixel detection and data reduction, known as a spectral retrieval or unmixing algorithm, will prove useful in the analysis of data from scheduled TIR orbital instruments. This study represents the first quantitative attempt to identify the limits of the model, specifically concentrating on the TIR. The algorithm was written and applied to laboratory data, testing the effects of particle size, noise, and multiple endmembers, then adapted to operate on airborne Thermal Infrared Multispectral Scanner data of the Kelso Dunes, CA, Meteor Crater, AZ, and Medicine Lake Volcano, CA. Results indicate that linear spectral unmixmg can produce accurate endmember detection to within an average of 5%. In addition, the effects of vitrification and textural variations were modeled. The ability to predict mineral or rock abundances becomes extremely useful in tracking sediment transport, decertification, and potential hazard assessment in remote volcanic regions. 26 refs., 3 figs.

Ramsey, M.S. [Arizona State Univ., Tempe, AZ (United States)

1996-11-01

138

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.

139

Optical and near-infrared observations of BL Lacertae objects and active quasars  

NASA Technical Reports Server (NTRS)

UBVRI and JHK photometric and polarimetric observations, obtained using the 1.5-m UCSD/UM telescope at Mount Lemmon, AZ during 1982-1984, are reported for a sample of 10 BL Lac objects, eight optically violent variable quasars, and the low-polarization quasar 3C 273. The data are presented in extensive tables and graphs and analyzed in detail. Most of the objects are found to have undergone large polarization variations on time scales ranging from 1 d to several months; five objects had fractional linear polarization P greater than 30 percent at least once during the period of observation, but four never had P greater than 10 percent. Of four objects which exhibited a preferred polarization position angle (theta), three had theta within 20 deg of the jet position angle determined by VLBI.

Smith, Paul S.; Balonek, Thomas J.; Elston, Richard; Heckert, Paul A.

1987-01-01

140

Near-infrared H2 and Continuum Survey of Extended Green Objects. II. Complete Census for the Northern Galactic Plane  

NASA Astrophysics Data System (ADS)

We discuss 94 Extended Green Objects (EGOs) in the northern Galactic plane cataloged by Cyganowski et al., based on near-infrared narrow H2 (2.122 ?m) and continuum observations from the United Kingdom Infrared Telescope. This data set is three times larger than the one in our previous study and is unbiased by preselection. As discussed in the previous paper, the morphologies of the 4.5 ?m emission generally resemble those of the near-infrared continuum, but are different from those of the H2 emission. Of our sample, only 28% of EGOs with H2 emission show similar morphologies between 4.5 ?m and H2 emission. These results suggest that the 4.5 ?m emission mainly comes from scattered continuum from the embedded young stellar objects, and partially from H2 emission. About half of EGOs are associated with H2 outflows, if the H2 outflow incompleteness is considered. The H2 outflow detection rate for EGOs with K-band detections (61%) is significantly higher than for those without K-band detections (36%). This difference may be due to the fact that both H2 and K-band emissions are associated with outflows, i.e., H2 emission and K-band continuum are associated with shocks and outflow cavities, respectively. We also compared the correlation between the H2 outflows and Class I 44 GHz methanol masers from the literature. The methanol masers can be located upstream or downstream of the H2 outflows and some bright H2 spots or outflows are not associated with methanol masers, suggesting that methanol masers and H2 emission trace different excitation conditions.

Lee, Hsu-Tai; Liao, Wei-Ting; Froebrich, Dirk; Karr, Jennifer; Ioannidis, Georgios; Lee, Yong-Hyun; Su, Yu-Nung; Liu, Sheng-Yuan; Duan, Hao-Yuan; Takami, Michihiro

2013-10-01

141

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

142

Infrared Photometry of Sakurai's Object (V4334 Sgr) in 1996-1999  

NASA Astrophysics Data System (ADS)

The infrared photometric observations of V4334 Sgr in 1996-1999 are presented. Together with optical data, they have allowed us to accurately estimate the bolometric flux from this star and to investigate the structure of its dust envelope over the above period. The star is shown to have passed through four well-defined stages in these four years as it moved backward along the post-AGB track, and it now appears to have started moving forward after a halt. At the first stage (1996), there was no dust in the star's envelope. Its visual brightness slightly increased, and it reddened in the entire observed spectral range. The bolometric flux also gradually rose. At the second stage (1997), an optically thick dust envelope condensed around the star, which, however, essentially did not manifest itself at optical wavelengths. The bolometric flux continued to rise through an increase in the star's infrared brightness alone; the rate of its rise also increased. At the third stage (1998-March 1999), V4334 Sgr entered the R CrB phase. First two shallow minima and then two deep minima were observed at optical wavelengths. The star appreciably reddened during the deep minima. The bolometric flux ceased to rise and began to gradually fall in the second half of 1998. At the fourth stage (since March 1999 up until now), V4334 Sgr has been at a protracted deep minimum, which is atypical of the R CrB stars. The bolometric flux between March and October underwent no significant variations. We describe the structure of the dust envelope around V4334 Sgr since its formation. From June 1997 until July 1998, the optical depth of the dust shell, its inner and outer radii, and its mass increased by factors of 2.2, 2.0, 2.3, and 10, respectively. In July 1998, tau(V) was approximately equal to 2.3, R_{d, in} = 7.4 x 1014 cm, R_{d, in}/R_{d, out} = 0.7 (R_{d, in}/R_* = 47), and M_dust = 1.6 x 10^{-7} M_solar.

Tatarnikov, A. M.; Shenavrin, V. I.; Yudin, B. F.; Whitelock, P. A.; Feast, M. W.

2000-08-01

143

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

144

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

145

CorMASS: A Compact and Efficient Near-Infrared Spectrograph for Studying Low-Mass Objects  

NASA Astrophysics Data System (ADS)

CorMASS (Cornell Massachusetts Slit Spectrograph) is a compact, low-resolution (R~300), double-pass prism cross-dispersed near-infrared (NIR) spectrograph in operation on the Palomar Observatory 60 inch telescope. Its two-dimensional spectral format provides simultaneous coverage of ?~0.75 ?m to ?~2.5 ?m (?JHK bands). A remotely operated cold flip mirror permits its NICMOS3 detector to function as a Ks slit viewer to assist object placement into the 2''×15'' slit. CorMASS was primarily designed for the rapid spectral classification of low-mass stellar and substellar objects identified by the Two-Micron All Sky Survey (2MASS). The efficiency and resolution of CorMASS also make it a versatile instrument for the spectral observation and classification of many other types of bright objects (K<14) including quasars, novae, and emission-line objects. Observations made at the Palomar Observatory were made as part of a continuing collaboration between the California Institute of Technology and Cornell University. The 60 inch telescope at Palomar Mountain is jointly owned by the California Institute of Technology and the Carnegie Institution of Washington.

Wilson, J. C.; Skrutskie, M. F.; Colonno, M. R.; Enos, A. T.; Smith, J. D.; Henderson, C. P.; Gizis, J. E.; Monet, D. G.; Houck, J. R.

2001-02-01

146

Scientific objectives and selection of targets for the SMART-1 Infrared Spectrometer (SIR)  

USGS Publications Warehouse

The European SMART-1 mission to the Moon, primarily a testbed for innovative technologies, was launched in September 2003 and will reach the Moon in 2005. On board are several scientific instruments, including the point-spectrometer SMART-1 Infrared Spectrometer (SIR). Taking into account the capabilities of the SMART-1 mission and the SIR instrument in particular, as well as the open questions in lunar science, a selection of targets for SIR observations has been compiled. SIR can address at least five topics: (1) Surface/regolith processes; (2) Lunar volcanism; (3) Lunar crust structure; (4) Search for spectral signatures of ices at the lunar poles; and (5) Ground truth and study of geometric effects on the spectral shape. For each topic we will discuss specific observation modes, necessary to achieve our scientific goals. The majority of SIR targets will be observed in the nadir-tracking mode. More than 100 targets, which require off-nadir pointing and off-nadir tracking, are planned. It is expected that results of SIR observations will significantly increase our understanding of the Moon. Since the exact arrival date and the orbital parameters of the SMART-1 spacecraft are not known yet, a more detailed planning of the scientific observations will follow in the near future. ?? 2004 Elsevier Ltd. All rights reserved.

Basilevsky, A.T.; Keller, H.U.; Nathues, A.; Mall, U.; Hiesinger, H.; Rosiek, M.

2004-01-01

147

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

148

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

149

Far-infrared observations of celestial objects by balloon-borne telescope.  

NASA Technical Reports Server (NTRS)

The instrument described is an f/5 Newtonian telescope with a parabolic pyrex primary mirror. The telescope tube is 1.5 m long. A 61 cm baffle is included to provide shielding from off-axis objects such as the earth, the moon, and the sun. An outline of the regions covered by sky surveys in June 1970 and in April 1971 is presented. Approximately 750 square degrees of the sky have been covered, including 100 degrees along the galactic plane.

Hoffmann, W. F.

1972-01-01

150

Spectral Indices of Faint Radio Sources  

NASA Astrophysics Data System (ADS)

The significant improvement in bandwidth and the resultant sensitivity offered by the Karl G. Jansky Very Large Array (VLA) allows us to explore the faint radio source population. Through the study of the radio continuum we can explore the spectral indices of these radio sources. Robust radio spectral indices are needed for accurate k-corrections, for example in the study of the radio - far-infrared (FIR) correlation. We present an analysis of measuring spectral indices using two different approaches. In the first, we use the standard wideband imaging algorithm in the data reduction package CASA. In the second, we use a traditional approach of imaging narrower bandwidths to derive the spectral indices. For these, we simulated data to match the observing parameter space of the CHILES Con Pol survey (Hales et al. 2014). We investigate the accuracy and precision of spectral index measurements as a function of signal-to noise, and explore the requirements to reliably probe possible evolution of the radio-FIR correlation in CHILES Con Pol.

Gim, Hansung B.; Hales, Christopher A.; Momjian, Emmanuel; Yun, Min Su

2015-01-01

151

High-resolution reconstruction of objects from cloud-covered infrared images  

NASA Astrophysics Data System (ADS)

FLIR images are essential for the detection and recognition of ground targets. Small targets can be enhanced using super-resolution techniques to improve the effective resolution of the target area using a sequence of low-resolution images. However, when there is significant cloud cover, several problems can arise: clouds can obscure a target (partially or fully), they can affect the accuracy of image registration algorithms, and they can reduce the contrast of the object against the background. To reconstruct an image in the presence of cloud cover, image correlation metrics from optical flow and a robust super-resolution algorithm have been used to compile a 'best' frame.

Wang, Jing; Ralph, Jason F.; Goulermas, John Y.

2009-05-01

152

FAINT UV OBJECTS IN THE CORE OF GGCs: A NEW SUBCLASS OF CVs? \\Lambda F.R. Ferraro 1 , B. Paltrinieri 1 , F. Fusi Pecci 1;2 , R.T. Rood 3 , B. Dorman 3;4  

E-print Network

objects are most often connected to binary systems containing compact objects (like neutron stars or white.e., bi­ nary systems in which a white dwarf (instead of a neutron star) is accreting material from a late the error boxes of LLGCXs recently found by Fox et al (1996). 2. OBSERVATIONS HST­WFPC2 frames were obtained

Rood, Robert T.

153

Cataclysmic Variables from the Faint Sky Variability Survey  

NASA Astrophysics Data System (ADS)

The Faint Sky Variability Survey is a large, deep field, optical, photometric survey using the Wide-Field Camera at the Isaac Newton Telescope on La Palma. Approximately 18 square degrees have been observed photometrically in BVI colors with variability sampling of 10's of minutes to years. Current population synthesis models for cataclysmic variables (CVs) predict the majority (70%) have passed the orbital period minimum of 80 min. Such systems are intrinsically faint with very low mass transfer rates and a brown dwarf-like secondary object as the mass donor. An observational bias from apparent magnitude limits in the past has revealed a dominant population of intrinsically brighter CVs and very few of the low-luminosity type past the 80 min period minimum. The large area coverage and faintness limits of the FSVS provide a significant volume sample in order to locate the intrinsically faint population of cataclysmic variables predicted to be the dominant population by interacting binary evolutionary theory. Cataclysmic variables candidates are selected by color (B-V, V-I) and intrinsic variability (orbital modulations and flickering), a unique parameter for a large survey to very deep limits in V of 23 mags. We will present and discuss the current results in the search for elusive low-luminosity cataclysmic variables including the selection process, follow-up observations, and estimated space densities. MEH acknowledges support from by a NASA/Space Grant Fellowship, NASA Grant #NGT-40008.

Huber, M. E.; Howell, S. B.

2001-12-01

154

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini  

NASA Astrophysics Data System (ADS)

We report on the design, on-sky performance, and status of the FLAMINGOS-2 instrument - the fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048- pixel HAWAII-2 0.9-2.4 ?m detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the on-sky performance measured during acceptance testing in 2009, as well as current status of the project and future plans.

Eikenberry, Stephen; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Charcos, Miguel; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Elston, Richard; Frommeyer, Skip; Gonzalez, Anthony; Hanna, Kevin; Herlevich, Michael; Hon, David; Julian, Jeff; Julian, Roger; Lasso, Nestor; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Raines, S. N.; Rambold, William; Rashkind, David; Warner, Craig; Leckie, Brian; Gardhouse, W. R.; Fletcher, Murray; Hardy, Tim; Dunn, Jennifer; Wooff, Robert; Pazder, John

2012-09-01

155

Design and development of SWIMS: a near-infrared multi-object spectrograph for the University of Tokyo Atacama Observatory  

NASA Astrophysics Data System (ADS)

SWIMS (Simultaneous-color Wide-field Infrared Multi-object Spectrograph) is one of the first-generation instruments for the University of Tokyo Atacama Observatory (TAO; P.I.: Yuzuru Yoshii) 6.5-m telescope which is planned to be constructed at the world's highest site, the summit of Cerro Chajnantor (an altitude of 5,640 m or 18,500 ft) in northern Chile. By placing a dichroic mirror into the collimated beam, SWIMS is capable of wide-field (? 9'.6 with 0".126 pixel-1) two-color simultaneous imaging as well as multi-object spectroscopy (MOS) using cooled multi-slit masks covering the entire near-infrared spectra between 0.9 and 2.5 ?m in a single exposure with low-to-medium spectral resolutions. Up to 20 user-defined slit masks as well as long slit masks are available. The field of view is covered with four 2048 x 2048 pixel HgCdTe focal plane arrays (HAWAII-2RG). Tests of the MOS slit mask exchanger motions have been completed successfully without any trouble under cryogenic environment. Further MOS tests will be performed at various tilt and rotation angles of the instrument using a telescope simulator. Also, a conceptual study of a compact and cryogenic wide-field integral field spectroscopy unit handled by the slit mask exchanger is now being carried out. The part of the current designs is optimized for installation on the Subaru Telescope for performance verification and early scientific observations prior to the construction of the TAO 6.5-m telescope. In this paper, we present the design and development status of the instrument.

Konishi, Masahiro; Motohara, Kentaro; Takahashi, Hidenori; Tateuchi, Ken; Kitagawa, Yutaro; Kato, Natsuko; Aoki, Tsutomu; Doi, Mamoru; Handa, Toshihiro; Kamizuka, Takafumi; Kawara, Kimiaki; Kohno, Kotaro; Koshida, Shintaro; Minezaki, Takeo; Miyata, Takashi; Morokuma, Tomoki; Sako, Shigeyuki; Soyano, Takao; Tamura, Yoichi; Tanabe, Toshihiko; Tanaka, Masuo; Tarusawa, Ken'ichi; Yoshii, Yuzuru

2012-09-01

156

Sakurai's Object: characterising the near-infrared CO ejecta between 2003 and 2007  

E-print Network

We present observations of Sakurai's Object obtained at 1-5um between 2003 and 2007. By fitting a radiative transfer model to an echelle spectrum of CO fundamental absorption features around 4.7um, we determine the excitation conditions in the line-forming region. We find 12C/13C~3.5, consistent with CO originating in ejecta processed by the very late thermal pulse, rather than in the pre-existing planetary nebula. We demonstrate the existence of 2.2e-6

H L. Worters; M. T. Rushton; S. P. S. Eyres; T. R. Geballe; A. Evans

2008-10-24

157

The faint end of the galaxy luminosity function  

NASA Technical Reports Server (NTRS)

The evolution of the B- and K-band luminosity functions of galaxies is inferred in a relatively model-independent way from deep spectroscopic and photometric surveys. We confirm earlier evidence by Eales for an increase in the amplitude of the B-band galaxy luminosity function at modest redshift (z less than or approx. 0.2). We find in addition that the slope of the faint end of the luminosity function must systematically steepen and progress toward more luminous galaxies with increasing lookback time, assuming that the galaxy redshift distribution may be smoothly extrapolated 2 mag fainter than observed, as suggested by recent gravitational lensing studies. This evolution is shown to be color-dependent, and we predict the near-infrared color distribution of faint galaxies. The luminosity function of blue (B - K less than or approx. 4) galaxies in the range 0.2 less than or approx. z less than or approx. 1 can be represented by a Schechter function with characteristic light density phi(sup *) L(sup *) comparable to that of present-day late-type galaxies, but with a steeper faint end slope alpha approx. 1.4.

Treyer, Marie A.; Silk, Joseph

1994-01-01

158

The Faint Sky Variability Survey I: An Overview  

E-print Network

The Faint Sky Variability Survey is aimed at finding variable objects in the brightness range between 17th and 25th magnitude on timescales between tens of minutes and years with photometric precisions ranging from 3 millimagnitudes for the brightest to 0.2 magnitudes for the faintest objects. An area of at least 50 square degrees, located at mid-galactic latitudes, will be covered using the Wide Field Camera on the 2.5m Isaac Newton Telescope on La Palma. The survey started in November 1998 as part of the INT Wide Field Survey program. Here we describe the main goals of the Faint Sky Variability Survey, the methods used in extracting the relevant information and the future prospects of the survey.

P. J. Groot; P. M. Vreeswijk; M. E. Everett; S. B. Howell

2000-09-29

159

Faint Young Sun, Radiocarbon dating  

NSDL National Science Digital Library

The first problem in this assignment is the culmination of the unit on energy balance and greenhouse gases. The students have already calculated blackbody temperatures as a function of albedo, sun's luminosity and distance from sun. They have also already calculated the magnitude of the greenhouse effect (optical thickness) of the modern atmosphere. In this first problem, the students apply these same calculations to the Faint Young Sun hypothesis and infer what can account for the geological evidence for liquid water on earth since 4.3 Ga. The second problem follows an introductory lecture on radiometric decay and radiometric dating. The students have seen the decay equation and learned what are decay constants and stable versus radioactive isotopes. In this problem, the students apply these concepts to radiocarbon.

Cook, Mea

160

Objective  

E-print Network

On March 15, 2005, EPA announced the final regulations for mercury emissions from coal-fired power plants. The regulations embrace a cap-and-trade approach, which favors the use of combinations of existing air pollution control equipment (“co-benefits”). To effectively satisfy the new regulations and remove mercury from flue gas, an adequate fundamental understanding of the system chemistry is required. The objective of this project is to understand the importance of gas- and solid-phase constituents in mercury oxidation reaction chemistry. The effects of chlorine, nitrogen oxide, sulfur dioxide and ash particles on mercury oxidation are being studied. These oxidation reactions are believed to be important because oxidized mercury is effectively removed by wet flue gas desulfurization systems at no additional cost to plant operation. Accomplishments To Date At the University of Utah, the mercury analysis equipment, designed and constructed by Southern Research Institute, has been tested and proven to be effective. Mercury analysis has been performed on a 5 MMBtu/hr coal-fired boiler and mercury concentrations and speciation varied with changes in boiler operation as expected. Introduced mercury spikes were also recovered adequately. The mercury sampling and conditioning system were modified to analyze mercury during gas phase experimentation in a natural gas-fired, quartz-line, drop-tube furnace. Mercury mass balances were performed in the drop tube furnace and discrepancies between calculated

Andrew Fry; Joann S. Lighty (pi; Geoffrey D. Silcox (co-pi; Joseph Helble

2004-01-01

161

HUBBLE'S SEARCH FOR FAINT FIELD STARS IN GALACTIC HALO  

NASA Technical Reports Server (NTRS)

Left A NASA Hubble Space Telescope image of a randomly selected area of sky taken to search for faint red stars that might constitute dark matter in our Milky Way Galaxy. (Dark matter is material of an unknown type that makes up most of the mass of our galaxy). If the dark matter in our Galaxy was made of faint red stars -- as many scientists have previously conjectured -- then about 38 such stars should have been visible in this HST image. The simulated stars (diamond-shaped symbols), based on theoretical calculations, illustrate what scientists would have seen if the dark matter were locked-up in faint red stars. These surprising results rule out dim stars as an explanation for dark matter in our Galaxy. Right The unmodified HST image shows the region is actually so devoid of stars that far more distant background galaxies can easily be seen. The field is in the constellation Eridanus, far outside the plane of our Milky Way Galaxy. This region was chosen to highlight stars in the galactic halo, where dark matter exists, and to avoid the contribution of faint stars in the plane of the Galaxy. Technical Information: The image was constructed from seven exposures totaling almost three hours of searching by HST. The field shown is about 1.5 arc-minutes across. The image was taken in near-infrared light (814 nm) with the Wide Field Planetary Camera 2, on Feb 8, 1994. This observation is part of the HST parallel observing program. Credit: J Bahcall, Institute for Advance Study, Princeton and NASA

2002-01-01

162

SN 2003lw and GRB 031203: A Bright Supernova for a Faint Gamma-Ray Burst  

Microsoft Academic Search

Optical and near-infrared observations of the gamma-ray burst GRB 031203, at z=0.1055, are reported. A very faint afterglow is detected superposed onto the host galaxy in our first infrared JHK observations, carried out ~9 hr after the burst. Subsequently, a rebrightening is detected in all bands, peaking in the R band about 18 rest-frame days after the burst. The rebrightening

D. Malesani; G. Tagliaferri; G. Chincarini; M. Della Valle; P. A. Mazzali; F. M. Zerbi; P. D'Avanzo; S. Kalogerakos; A. Simoncelli; L. A. Antonelli; A. Cucchiara; S. Campana; F. Fiore; G. Ghirlanda; P. Goldoni; D. Götz; S. Mereghetti; I. F. Mirabel; P. Romano; L. Stella; T. Minezaki; Y. Yoshii; K. Nomoto

2004-01-01

163

Updated optical design and trade-off study for MOONS, the Multi-Object Optical and Near Infrared spectrometer for the VLT  

E-print Network

This paper presents the latest optical design for the MOONS triple-arm spectrographs. MOONS will be a Multi-Object Optical and Near-infrared Spectrograph and will be installed on one of the European Southern Observatory (ESO) Very Large Telescopes (VLT). Included in this paper is a trade-off analysis of different types of collimators, cameras, dichroics and filters.

Oliva, E; Cirasuolo, M; Schnetler, H; Lunney, D; Rees, P; Bianco, A; Diolaiti, E; Ferruzzi, D; Fisher, M; Guinouard, I; Iuzzolino, M; Parry, I; Sun, X; Tozzi, A; Vitali, F

2014-01-01

164

Identification of Class I Methanol Masers with Objects of Near and Mid-Infrared Bands and the Third Version of the Class I Methanol Maser (MMI) Catalog  

NASA Astrophysics Data System (ADS)

An identification has been conducted of class I methanol masers with 1) short-wave infrared objects EGO (extended green objects) - tracer bipolar outflow of matter in young stellar objects, and 2) isolated pre-protostellar gas-dust cores of the interstellar medium which are observed in absorption in the mid-infrared in the Galactic plane. It is shown that more than 50% of class I methanol masers are identified with bipolar outflows, considering the EGO as bipolar outflows (as compared with the result of 22% in the first version of the MMI catalog that contains no information about EGO). 99 from 139 class I methanol masers (71%) are identified with SDC. Thus, it seems possible that the MMI can be formed in isolated self-gravitating condensations, which are the silhouette of dark clouds - IRDC and SDC.

Bayandina, Olga; Val'tts, Irina; Larionov, Grigorii

2012-07-01

165

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

166

Extending the infrared radio correlation  

NASA Astrophysics Data System (ADS)

Co-addition of deep (rms ~ 30?Jy) 20-cm data obtained with the Australia Telescope Compact Array at the location of Spitzer Wide Field Survey (SWIRE) sources has yielded statistics of radio source counterparts to faint 24-?m sources in stacked images with rms < 1?Jy. We confirm that the infrared-radio correlation extends to f24?m = 100?Jy but with a significantly lower coefficient, f20cm = 0.039f24?m [q24 = log(f24?m/f20cm) = 1.39 +/- 0.02] than hitherto reported. We postulate that this may be due to a change in the mean q24 value ratio for objects with f24?m < 1 mJy.

Boyle, B. J.; Cornwell, T. J.; Middelberg, E.; Norris, R. P.; Appleton, P. N.; Smail, Ian

2007-04-01

167

Direct and quantitative broadband absorptance spectroscopy on small objects using Fourier transform infrared spectrometer and bilayer cantilever probes  

E-print Network

A measurement platform is introduced that combines a bilayer cantilever probe with a Fourier transform infrared spectrometer to measure absolute spectral absorptance between wavelengths of 3??m and 18??m directly and ...

Hsu, Wei-Chun

168

Faint Submillimeter Galaxy Counts at 450 ?m  

NASA Astrophysics Data System (ADS)

We present the results of SCUBA-2 observations at 450 ?m and 850 ?m of the field lensed by the massive cluster A370. With a total survey area >100 arcmin2 and 1? sensitivities of 3.92 and 0.82 mJy beam-1 at 450 and 850 ?m, respectively, we find a secure sample of 20 sources at 450 ?m and 26 sources at 850 ?m with a signal-to-noise ratio (S/N) > 4. Using the latest lensing model of A370 and Monte Carlo simulations, we derive the number counts at both wavelengths. The 450 ?m number counts probe a factor of four deeper than the counts recently obtained from the Herschel Space Telescope at similar wavelengths, and we estimate that ~47%-61% of the 450 ?m extragalactic background light resolved into individual sources with 450 ?m fluxes greater than 4.5 mJy. The faint 450 ?m sources in the 4? sample have positional accuracies of 3 arcsec, while brighter sources (S/N >6?) are good to 1.4 arcsec. Using a deep radio map (1? ~ 6 ?Jy) we find that the percentage of submillimeter sources having secure radio counterparts is 85% for 450 ?m sources with intrinsic fluxes >6 mJy and 67% for 850 ?m sources with intrinsic fluxes >4 mJy. We also find that 67% of the >4? 450 ?m sources are detected at 850 ?m, while the recovery rate at 450 ?m of >4? 850 ?m sources is 54%. Combined with the source redshifts estimated using millimetric flux ratios, the recovered rate is consistent with the scenario where both 450 ?m and 20 cm emission preferentially select lower redshift dusty sources, while 850 ?m emission traces a higher fraction of dusty sources at higher redshifts. We identify potential counterparts in various wavelengths from X-ray to mid-infrared and measure the multiwavelength photometry, which we then use to analyze the characteristics of the sources. We find three X-ray counterparts to our robust submillimeter sample (S/N > 5), giving an active galactic nucleus fraction for our 450 (850) ?m sample of 3/8 (3/9) or 38% (33%). We also find a correlation between the Ks band and the 850 ?m/20 cm flux ratio.

Chen, Chian-Chou; Cowie, Lennox L.; Barger, Amy J.; Casey, Caitlin. M.; Lee, Nicholas; Sanders, David B.; Wang, Wei-Hao; Williams, Jonathan P.

2013-01-01

169

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

170

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

171

The Faint Sky Variability Survey I: Goals and data reduction process  

E-print Network

The Faint Sky Variability Survey is aimed at finding photometric and/or astrometric variable objects in the brightness range between 16objects. An area of ~23 square degrees, located at mid and high Galactic latitudes, has been covered using the Wide Field Camera on the 2.5m Isaac Newton Telescope on La Palma. Here we describe the main goals of the Faint Sky Variability Survey and the data reduction process.

Paul J. Groot; Paul M. Vreeswijk; Mark E. Huber

2002-10-18

172

Digital image profilers for detecting faint sources which have bright companions, phase 2  

NASA Technical Reports Server (NTRS)

A breadboard image profiling system developed for the first phase of this project demonstrated the potential for detecting extremely faint optical sources in the presence of light companions. Experimental data derived from laboratory testing of the device supports the theory that image profilers of this type may approach the theoretical limit imposed by photon statistics. The objective of Phase 2 of this program is the development of a ground-based multichannel image profiling system capable of detecting faint stellar objects slightly displaced from brighter stars. We have finalized the multichannel image profiling system and attempted three field tests.

Morris, Elena; Flint, Graham

1991-01-01

173

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

174

An Objective Algorithm For the Identification of Convective Tropical Cloud Clusters In Geostationary Infrared Imagery Department of Atmospheric Sciences  

E-print Network

, K., 2008: Hurricane Satellite (HURSAT) data sets: Low-earth orbit infrared and microwave data. 28th Conf. Hurr. Trop. Meteor., Orlando, FL. Methodology Introduction Satellite Data Areas of concentrated (Knapp 2008) provides snapshots of basin-wide activity. Data are derived from the International Satellite

Hennon, Christopher C.

175

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

Microsoft Academic Search

We present images and spectra of the Cepheus E (Cep E) region at both optical and infrared wavelengths. Only the brightest region of the southern lobe of the Cep E outflow reveals optical emission, suggesting that the extinction close to the outflow source plays an important role in the observed difference between the optical and IR morphologies. Cep E is

S. Ayala; A. Noriega-Crespo; P. M. Garnavich; S. Curiel; A. C. Raga; K.-H. Böhm; J. Raymond

2000-01-01

176

The Faint End of the HI Mass Function  

E-print Network

We study the faint end of the HI mass function (HIMF) in order to test the predictions of the CDM theory on the number density of objects with small (dark) masses. The neutral hydrogen is much better tracer of the underlying mass distribution compared to the luminous matter and can be used to test the existence of a population of small galaxies in which the star formation has been partially or completely suppressed during cosmic evolution. Due to technical limitations, the existing HI surveys are not very sensitive to HI masses below 10^8 M_sun. We designed a blind HI survey to be sensitive to objects with small HI masses. The surveyed area is in the Canis Venatici groups of galaxies and covers in total ~ 86 deg^2 of sky, with observed velocities in the range -350 HI. All new HI detections fall in the lower part of the mass-histogram, confirming our ability to detect galaxies with small HI masses. The calculated HIMF is flat in the faint end regime (slope ~ -1), different from the steep rise predicted by CDM models. Possible effects of the environment on the estimated HIMF parameters are discussed.

K. Kovac; T. A. Oosterloo; J. M. van der Hulst

2005-08-02

177

Infrared Gallery  

NSDL National Science Digital Library

Human eyes cannot see infrared wavelengths, but with the help of false-color imaging, temperature differences become visible and invisible features are suddenly illuminated. This interactive gallery shows images of a variety of objects and geothermal features in both visible and infrared light, and explains why the infrared images show the items as they do. A background essay and list of discussion questions are also provided.

178

Infrared Space Observatory Observations of the 53W002 Group at 6.7 Microns: In Search of the Oldest Stellar Populations at z = 2.4  

Microsoft Academic Search

We present a deep Infrared Space Observatory (ISO) observation at 6.7 mum of the 53W002 group of galaxies and active galactic nuclei (AGNs) at z=2.4. This approximately samples the emitted K band. Faint, blue star-forming objects are not detected, as expected from their very blue color across the emitted optical and UV spectrum. However, 53W002 itself is detected at the

William C. Keel; Wentao Wu; Paul P. van der Werf; Rogier A. Windhorst; James S. Dunlop; Stephen A. Eales; Ian Waddington; Martha Holmes

2004-01-01

179

The Faint Sky Variability Survey II: Initial Results  

E-print Network

We discuss the first results from the Faint Sky Variability Survey (Groot et al. 2000). The data consist of V-band light curves, BVI colours, astrometry, and morphology information on several hundred thousand point and extended sources in the magnitude range V=17-25. We discuss the first 30 survey fields covering an area of 8.4 square degrees towards moderate and high galactic latitudes. We analyse the quality of and discuss our differential photometry light curves. We employ statistical methods to select variable objects and present example variable light curves. The distribution of the colours and magnitudes of point sources in the survey is discussed and compared to galactic star count models. Finally, we discuss our search for trans-Neptunian objects in the FSVS fields observed towards ecliptic opposition.

M. E. Everett; M. E. Huber; S. B. Howell

2000-09-29

180

New, Faint Satellite Galaxies of NGC253  

NASA Astrophysics Data System (ADS)

As part of the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), we present our initial search for faint dwarf galaxies around the nearby spiral galaxy NGC253 (D~3.5 Mpc). While simulations of structure formation match observational constraints on the largest scales, they struggle to reproduce observations below that of individual galaxies. For a point of comparison, and to extend the search for faint dwarf galaxies beyond the Local Group, we have begun a search for faint dwarfs around two of our nearest galaxy neighbors: Centaurus A and NGC253. Here we present five new dwarf galaxy candidates to NGC253, all in resolved stellar light. We summarize their basic properties including their structure, star formation history and distances. When complete, the PISCeS survey will provide a complete census of dwarf satellites around NGC253 down to M_V~-8, allowing for direct comparisons with simulations and recent work around both the Milky Way and M31.

Sand, David J.; Crnojevic, Denija; Caldwell, Nelson; Guhathakurta, Puragra; McLeod, Brian A.; Seth, Anil; Simon, Joshua D.; Strader, Jay

2015-01-01

181

NEAR-INFRARED H{sub 2} AND CONTINUUM SURVEY OF EXTENDED GREEN OBJECTS. II. COMPLETE CENSUS FOR THE NORTHERN GALACTIC PLANE  

SciTech Connect

We discuss 94 Extended Green Objects (EGOs) in the northern Galactic plane cataloged by Cyganowski et al., based on near-infrared narrow H{sub 2} (2.122 ?m) and continuum observations from the United Kingdom Infrared Telescope. This data set is three times larger than the one in our previous study and is unbiased by preselection. As discussed in the previous paper, the morphologies of the 4.5 ?m emission generally resemble those of the near-infrared continuum, but are different from those of the H{sub 2} emission. Of our sample, only 28% of EGOs with H{sub 2} emission show similar morphologies between 4.5 ?m and H{sub 2} emission. These results suggest that the 4.5 ?m emission mainly comes from scattered continuum from the embedded young stellar objects, and partially from H{sub 2} emission. About half of EGOs are associated with H{sub 2} outflows, if the H{sub 2} outflow incompleteness is considered. The H{sub 2} outflow detection rate for EGOs with K-band detections (61%) is significantly higher than for those without K-band detections (36%). This difference may be due to the fact that both H{sub 2} and K-band emissions are associated with outflows, i.e., H{sub 2} emission and K-band continuum are associated with shocks and outflow cavities, respectively. We also compared the correlation between the H{sub 2} outflows and Class I 44 GHz methanol masers from the literature. The methanol masers can be located upstream or downstream of the H{sub 2} outflows and some bright H{sub 2} spots or outflows are not associated with methanol masers, suggesting that methanol masers and H{sub 2} emission trace different excitation conditions.

Lee, Hsu-Tai; Karr, Jennifer; Su, Yu-Nung; Liu, Sheng-Yuan; Takami, Michihiro [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Liao, Wei-Ting [Department of Mechanical Engineering, National Taiwan University, 1 Roosevelt Rd., Section 4, Taipei 10617, Taiwan (China); Froebrich, Dirk; Ioannidis, Georgios [Centre for Astrophysics and Planetary Science, University of Kent, Canterbury CT2 7NH (United Kingdom); Lee, Yong-Hyun [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Duan, Hao-Yuan, E-mail: htlee@illinois.edu [Institute of Astronomy and Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan (China)

2013-10-01

182

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

183

A Large and Faint Photometric Catalog on the Ecliptic  

NASA Astrophysics Data System (ADS)

A photometric catalog, developed for the calibration of the Deep Ecliptic Survey, is presented. The catalog contains 213,272 unique sources that were measured in V and R filters and transformed to the Johnson-Cousins systems using the Landolt standard catalog. All of the sources lie within 6° of the ecliptic and cover all longitudes except for the densest stellar regions nearest the galactic center. Seventeen percent of the sources in the catalog are derived from three or more nights of observation. The catalog contains sources as faint as R ~19 but the largest fraction fall in the R ~15-16 (V ~16-17) mag range. All magnitude bins down to R = 19 have a significant fraction of objects with uncertainties <=0.1 mag.

Buie, Marc W.; Trilling, David E.; Wasserman, Lawrence H.; Crudo, Richard A.

2011-06-01

184

Detecting Moving Objects in Airborne Forward Looking InfraRed Sequences Alexander Strehl and J. K. Aggarwal \\Lambda  

E-print Network

,aggarwaljkg@mail.utexas.edu Abstract In this paper we propose a system that detects indepen­ dently moving objects (IMOs) in forward the integration of our robust system into a comprehensive au­ tomatic target recognition (ATR) and action classification system. 1 Introduction 1.1 Motivation Forward looking infra­red (FLIR) images are frequently used

Strehl, Alexander

185

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) high-resolution near-infrared multi-object fiber spectrograph  

NASA Astrophysics Data System (ADS)

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) will use a dedicated 300-fiber, narrow-band (1.5-1.7 micron), high resolution (R~30,000), near-infrared spectrograph to survey approximately 100,000 giant stars across the Milky Way. This survey, conducted as part of the Sloan Digital Sky Survey III (SDSS III), will revolutionize our understanding of kinematical and chemical enrichment histories of all Galactic stellar populations. The instrument, currently in fabrication, will be housed in a separate building adjacent to the 2.5 m SDSS telescope and fed light via approximately 45-meter fiber runs from the telescope. The instrument design includes numerous technological challenges and innovations including a gang connector that allows simultaneous connection of all fibers with a single plug to a telescope cartridge that positions the fibers on the sky, numerous places in the fiber train in which focal ratio degradation must be minimized, a large (290 mm x 475 mm elliptically-shaped recorded area) mosaic-VPH, an f/1.4 sixelement refractive camera featuring silicon and fused silica elements with diameters as large as 393 mm, three near-within a custom, LN2-cooled, stainless steel vacuum cryostat with dimensions 1.4 m x 2.3 m x 1.3 m.

Wilson, John C.; Hearty, Fred; Skrutskie, Michael F.; Majewski, Steven; Schiavon, Ricardo; Eisenstein, Daniel; Gunn, Jim; Blank, Basil; Henderson, Chuck; Smee, Stephen; Barkhouser, Robert; Harding, Al; Fitzgerald, Greg; Stolberg, Todd; Arns, Jim; Nelson, Matt; Brunner, Sophia; Burton, Adam; Walker, Eric; Lam, Charles; Maseman, Paul; Barr, Jim; Leger, French; Carey, Larry; MacDonald, Nick; Horne, Todd; Young, Erick; Rieke, George; Rieke, Marcia; O'Brien, Tom; Hope, Steve; Krakula, John; Crane, Jeff; Zhao, Bo; Carr, Mike; Harrison, Craig; Stoll, Robert; Vernieri, Mary A.; Holtzman, Jon; Shetrone, Matt; Allende-Prieto, Carlos; Johnson, Jennifer; Frinchaboy, Peter; Zasowski, Gail; Bizyaev, Dmitry; Gillespie, Bruce; Weinberg, David

2010-07-01

186

A Survey of Faint Galaxy Pairs  

E-print Network

A sample of faint, V magnitude selected, galaxy pairs, having physical separations less than approximately 20\\hkpc, is used to examine the rise in the merger rate with redshift and the statistical relations between close pairs and the field galaxy population. Redshifts have been obtained for 14 galaxies ($V \\le 22.5$) that are in close ($\\theta < 6\\arcs$) pairs, along with a comparison sample of 38 field galaxies. Two color photometry is available for about 1000 galaxies in the same fields. The average redshift of the $V\\le22.5$ field population is 0.36, statistically equal to the average redshift of 0.42 for the pairs. The similarity of the two redshift distributions, $\\Delta z\\le 0.1$, limits any differential luminosity enhancement of close pairs to less than half a magnitude. The pairs are somewhat bluer than the field and have nearly twice the average [O~II] detection rate of the field, but the differences are not statistically significant. The field population has an angular correlation at separations of $\\theta\\le$6\\arcs\\ higher than the inward extrapolation of $\\omega(\\theta)\\propto \\theta^{-0.8}$, which may be a population of ``companions'' not present at the current epoch, or, luminosity enhancement of intrinsically faint galaxies in pairs. Physical pairs comprise about 7\\% of the faint galaxies in our survey fields. The same physical separation applied to local galaxies finds only 2.6\\% in pairs. If the rise in close low relatively velocity pairs with redshift is parameterized as $(1+z)^m$, then $m=2.9\\pm0.8$. If all pairs at low velocities and $r\\le 20$\\hkpc\\ merge, then the

Carlberg; Pritchet; Infante

1994-01-31

187

Faint Core-Collapse Supernovae with Fallback  

NASA Astrophysics Data System (ADS)

A long GRB is thought to occur when a massive star ends its life and thus it is expected to be accompanied by a type Ic supernova (SN) which also results from a massive star. Several nearby long GRBs are observed with type Ic SNe. However, some nearby long GRBs are observed without SNe, even though they are close enough to be able to observe the accompanied SNe (e.g., GRB060614). Within our current picture of long GRBs, long GRBs should be accompanied by SNe and these long GRBs without SNe are one of the challenges for the current theory of long GRBs. One possible reason is that the accompanied SNe were so faint that we just missed them. For example, SN 2008ha was only as bright as ~-14 mag in the R band at maximum brightness. The explosion energy, ejecta mass, and 56Ni mass of SN 2008ha are estimated as about 1048 erg, 0.1 Msolar, and 0.003 Msolar, respectively. If such a SN is accompanied by long GRBs, we might miss it. We performed numerical calculations of hydrodynamics and radiation transport and confirmed that SN 2008ha could have been a type Ic supernova and originated from a core-collapse SN with a significant amount of fallback. This demonstrates that some type Ic SNe like SN 2008ha could be very faint because of fallback. Our results suggest that long GRBs without SNe could have been accompanied by such faint SNe with fallback and we could have just missed the accompanied SNe and the current picture of long GRBs would be consistent with long GRBs without SNe.

Moriya, Takashi; Tominaga, Nozomu; Tanaka, Masaomi; Nomoto, Ken'ichi; Sauer, Daniel N.; Mazzali, Paolo A.; Maeda, Keiichi; Suzuki, Tomoharu

2010-10-01

188

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

189

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

190

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

191

Near-infrared multiwavelength imaging polarimetry of the low-mass proto-stellar object HL Tauri  

NASA Astrophysics Data System (ADS)

We present the {JHK}-band high-resolution polarimetric images of the low-mass proto-stellar object HL Tau using the adaptive optics-equipped CIAO instrument on the Subaru telescope. Our polarization images show a butterfly-shaped polarization disk with an ˜0.9 arcsec × 3.0 arcsec extension. In the nebula, where polarization vectors are centro-symmetrically aligned, the polarization is as high as PJ ˜30%, P_H˜42%, and PK ˜55%. On the other hand, low polarizations of P<3% in the J, H, and K bands and a low color excess ratio of EJ-H/EH-K=1.1 compared to the standard cloud value of 1.75 are detected towards the central star. We estimated the upper limit of the grain sizes a_max to be 0.4 ?m in the nebula and ?0.7 ?m in the line of sight towards the central star. Our high-resolution polarimetric data, which spatially resolves the polarization disk, provides us with important information about grain growth in the region close to the central star.

Murakawa, K.; Oya, S.; Pyo, T.-S.; Ishii, M.

2008-12-01

192

An All-Sky Catalog of Faint Extreme Ultraviolet Sources  

NASA Astrophysics Data System (ADS)

We present a list of 534 objects detected jointly in the Extreme Ultraviolet Explorer (EUVE) 100 Å all-sky survey and in the ROSAT X-Ray Telescope 0.25 keV band. The joint selection criterion permits use of a low count rate threshold in each survey. This low threshold is roughly 60% of the threshold used in the previous EUVE all-sky surveys, and 166 of the objects listed here are new EUV sources, appearing in neither the Second EUVE Source Catalog nor the ROSAT Wide Field Camera Second Catalog. The spatial distribution of this all-sky catalog shows three features: an enhanced concentration of objects in Ursa Major, where the Galactic integrated H I column reaches its global minimum; an enhanced concentration in the third quadrant of the Galaxy (lII from 180° to 270°) including the Canis Major tunnel, where particularly low H I columns are found to distances beyond 200 pc; and a particularly low number of faint objects in the direction of the fourth quadrant of the Galaxy, where nearby intervening H I columns are appreciable. Of particular interest is the composition of the 166 detections not previously reported in any EUV catalog. We offer preliminary identifications for 105 of these sources. By far the most numerous (81) of the identifications are late-type stars (F, G, K, M), while 18 are other stellar types, only five are white dwarfs (WDs), and none are extragalactic. The paucity of WDs and extragalactic objects may be explained by a strong horizon effect wherein interstellar absorption strongly limits the effective new-source search volume and, thereby, selectively favors low-luminosity nearby sources over more luminous but distant objects.

Lampton, M.; Lieu, R.; Schmitt, J. H. M. M.; Bowyer, S.; Voges, W.; Lewis, J.; Wu, X.

1997-02-01

193

[Preventing fainting due to needles or blood].  

PubMed

A 29-year-old medical student suffered from vasovagal syncope triggered by blood and blood-related procedures, such as injections and injuries. Fainting was preceded by prodromal symptoms like light-headedness and altered vision. The patient consulted the Syncope Unit at the Academic Medical Centre, Amsterdam, the Netherlands, and received instructions on how to apply counterpressure manoeuvres. He was also successfully treated with psychological deconditioning, which consisted of desensitisation through exposure in vivo and cognitive behavioural therapy. Emotionally triggered vasovagal syncope is predominantly seen in young people and can lead to serious complications. It can be treated with simple interventions like drinking water and performing counterpressure manoeuvres. Psychological deconditioning is an effective additional therapy. PMID:20619039

Busweiler, Linde A D; de Jong, Jean Philippe; Beunderman, Ruud; van Dijk, Nynke; Wieling, Wouter

2010-01-01

194

Star formation in infrared bright and infrared faint starburst interacting galaxies  

NASA Technical Reports Server (NTRS)

Short wavelength IUE spectra of Arp 248b and UGC 8315N are combined with optical spectra and interpreted using a combination of spectrum synthesis and spectral diagnostics to place constraints on the massive star populations of the central regions of these galaxies and to deduce information about the star formation histories in the last 10(exp 8) years. The authors find that both galaxies have substantial fractions of their optical light coming from massive stars and that Arp 248b may be dominated in the UV by WR stars. The UV spectra are dominated by radiation from evolved massive stars and the authors place and age on the burst in Arp 248b of a few tens of millions of years.

Lamb, Susan A.; Bushouse, Howard A.; Towns, John W.

1990-01-01

195

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

196

Accurate shear measurement with faint sources  

NASA Astrophysics Data System (ADS)

For cosmic shear to become an accurate cosmological probe, systematic errors in the shear measurement method must be unambiguously identified and corrected for. Previous work of this series has demonstrated that cosmic shears can be measured accurately in Fourier space in the presence of background noise and finite pixel size, without assumptions on the morphologies of galaxy and PSF. The remaining major source of error is source Poisson noise, due to the finiteness of source photon number. This problem is particularly important for faint galaxies in space-based weak lensing measurements, and for ground-based images of short exposure times. In this work, we propose a simple and rigorous way of removing the shear bias from the source Poisson noise. Our noise treatment can be generalized for images made of multiple exposures through MultiDrizzle. This is demonstrated with the SDSS and COSMOS/ACS data. With a large ensemble of mock galaxy images of unrestricted morphologies, we show that our shear measurement method can achieve sub-percent level accuracy even for images of signal-to-noise ratio less than 5 in general, making it the most promising technique for cosmic shear measurement in the ongoing and upcoming large scale galaxy surveys.

Zhang, Jun; Luo, Wentao; Foucaud, Sebastien

2015-01-01

197

Clouds and the Faint Young Sun Paradox  

E-print Network

We investigate the role which clouds could play in resolving the Faint Young Sun Paradox (FYSP). Lower solar luminosity in the past means that less energy was absorbed on Earth (a forcing of -50 Wm-2 during the late Archean), but geological evidence points to the Earth being at least as warm as it is today, with only very occasional glaciations. We perform radiative calculations on a single global mean atmospheric column. We select a nominal set of three layered, randomly overlapping clouds, which are both consistent with observed cloud climatologies and reproduce the observed global mean energy budget of Earth. By varying the fraction, thickness, height and particle size of these clouds we conduct a wide exploration of how changed clouds could affect climate, thus constraining how clouds could contribute to resolving the FYSP. Low clouds reflect sunlight but have little greenhouse effect. Removing them entirely gives a~forcing of +25 Wm-2 whilst more modest reduction in their efficacy gives a forcing of +10 ...

Goldblatt, Colin

2011-01-01

198

Discovery of a faint Field Methane Brown Dwarf from ES0 NTT and VLT observations  

E-print Network

We report the discovery of an isolated brown dwarf with similar properties to the binary object Gliese 229B and to the newly discovered field brown dwarf SDSS 1624+00. Although exhibiting similar colors, its magnitude of ~20.5 is about 6 and 5 magnitudes fainter than Gliese 229B and SDSS 1624+00 respectively. This is the third methane brown dwarf reported to date, the second isolated one in the field and by far the most distant at ~ 100 pc. Its IR spectrum, although at low S/N given the faintness of the object, is remarkably similar to those of the 2 other methane brown dwarfs.

J. G. Cuby; P. Saracco; A. F. M. Moorwood; S. D'Odorico; C. Lidman; F. Comeron; J. Spyromilio

1999-08-13

199

The Strömvil Photometric System: Classifying Faint Stars  

NASA Astrophysics Data System (ADS)

Since 1996 a group of astronomers has been working on setting up and then using the Strömvil photometric system, a combination of the four Strömgren and three Vilnius system filters. The system was announced in Straižys et al. (1996). A summary of the work up to 2003 can be found in S?džius et al. (2003). The major ability of the Strömvil system is that, from photoelectric measures alone one can determine the reddening, temperature, gravity and metalicity of stars. With all the new surveys that have been made and ones yet to be made, such a system will be of great use to identify the nature of the new faint stars that will be identified and classify them by stellar type. And since the reddening can be calculated for each region, the intrinsic properties of these stars can be determined. The main observational programs underway in the Strömvil system at present are: 1. Setting up the primary standards. Kazlauskas et al. (2005) have published a list of 780 photoelectric standards in the northern hemisphere. 2. At the Vatican Advanced Technology Telescope on Mt. Graham Boyle and Philip have been making CCD Strömvil measures of open and globular clusters. Observations are taken in each run of the rich open cluster M 67. These measures are matched to the high-accuracy CCD photometry of Laugalys et al. (2004) by constraining the corrections to each flatfield to provide the needed one percent photometry in new program fields with only a few standards for zero-point calibration. 3. At Casleo, in Argentina, Philip and Pintado have been observing clusters with the 2.15 meter telescope. 4. On the data reduction side Janusz and Boyle have written the CommandLog which automates the process of data reduction for members of our group. This will ensure that all observations will be reduced in exactly the same way.

Philip, A. G. D.; Boyle, R. P.

2006-08-01

200

Looking Deep with Infrared Eyes  

NASA Astrophysics Data System (ADS)

Today, British astronomers are releasing the first data from the largest and most sensitive survey of the heavens in infrared light to the ESO user community. The UKIRT Infrared Deep Sky Survey (UKIDSS) has completed the first of seven years of data collection, studying objects that are too faint to see at visible wavelengths, such as very distant or very cool objects. New data on young galaxies is already challenging current thinking on galaxy formation, revealing galaxies that are massive at a much earlier stage of development than expected. These first science results already show how powerful the full survey will be at finding rare objects that hold vital clues to how stars and galaxies in our Universe formed. UKIDSS will make an atlas of large areas of the sky in the infrared. The data become available to the entire ESO user community immediately after they are entered into the archive [2]. Release to the world follows 18 months after each release to ESO. "Astronomers across Europe will jump on these exciting new data. We are moving into new territory - our survey is both wide and deep, so we are mapping huge volumes of space. That's how we will locate rare objects - the very nearest and smallest stars, and young galaxies at the edge of the universe," said Andy Lawrence from the University of Edinburgh, UKIDSS Principal Investigator. The UKIDSS data are collected by the United Kingdom Infrared Telescope [3] situated near the summit of Mauna Kea in Hawaii using the Wide Field Camera (WFCAM) built by the United Kingdom Astronomy Technology Centre (UKATC) in Edinburgh. WFCAM is the most powerful infrared imager in the world, generating enormous amounts of data - 150 gigabytes per night (equivalent to more than 200 CDs) - and approximately 10.5 Terabytes in total so far (or 15,000 CDs). Mark Casali, now at ESO, was the Project Scientist in charge of the WFCAM instrument construction at the UKATC. "WFCAM was a bold technological undertaking," said Mark Casali. "Nothing quite like it has ever been built before. The fact that it is working reliably and reaching its theoretical sensitivity is a testament to the hard work and skill of the engineering team at the UKATC." ESO PR Photo 24a/06 ESO PR Photo 26a/06 Faint Red Galaxy in the UKIDSS Ultra-Deep Survey A small amount of data was released in January 2006 and already teams led by Omar Almaini at the University of Nottingham and Nigel Hambly of the Institute for Astronomy at the University of Edinburgh are beginning to reveal some of the secrets of star and galaxy formation. Omar Almaini, Ross McLure and the Ultra Deep Survey team have been looking at distant galaxies by surveying the same region of sky night after night to see deeper and to find these very faint objects. This survey will be one hundred times larger than any similar survey attempted to date and will cover an area four times the size of the full Moon. So far several hundred thousand galaxies have been detected and among the early discoveries, nine remarkable galaxies have been found that appear to be 12 billion light years away. As it has taken 12 billion years for the light to travel from these galaxies to Earth, we are seeing them as they were when they were very young - only a billion years after the Big Bang. The newly discovered galaxies are unusual as they appear to be very massive for their age. This challenges thinking on how galaxies form, since it was thought that large galaxies form gradually over billions of years as smaller components merge together. "We're surveying an enormous volume of the distant Universe, which allows us to discover rare massive galaxies that were previously almost impossible to find. Understanding how these galaxies form is one of the Holy Grails of modern astronomy, and now we can trace them back to the edge of the known Universe" said Omar Almaini. ESO PR Photo 26b/06 ESO PR Photo 26b/06 Brown Dwarf Candidates in the Pleiades Cluster (UKIDSS) Nigel Hambly and Nicolas Lodieu have been using the UKIDSS data to discover more about ve

2006-07-01

201

A Deep Multicolor Survey. VI. Near-Infrared Observations, Selection Effects, and Number Counts  

E-print Network

I present near-infrared J (1.25um), H (1.65um), and K (2.2um) imaging observations of 185 square arcminutes in 21 high galactic latitude fields. These observations reach limiting magnitudes of J ~ 21 mag, H ~ 20 mag and K ~ 18.5 mag. The detection efficiency, photometric accuracy and selection biases as a function of integrated object brightness, size, and profile shape are quantified in detail. I evaluate several popular methods for measuring the integrated light of faint galaxies and show that only aperture magnitudes provide an unbiased measure of the integrated light that is independent of apparent magnitude. These J, H, and K counts and near-infrared colors are in best agreement with passive galaxy formation models with at most a small amount of merging (for Omega_M = 0.3, Omega_Lambda = 0.7).

Paul Martini

2000-10-18

202

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

203

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

204

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

205

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

206

Methods for Estimating Fluxes and Absorptions of Faint X-ray Sources  

NASA Astrophysics Data System (ADS)

X-ray sources with very few counts can be identified with low-noise X-ray detectors such as the Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory. These sources are often too faint for parametric spectral modeling using well-established methods such as fitting with XSPEC. We discuss the estimation of apparent and intrinsic broadband X-ray fluxes and soft X-ray absorption from gas along the line of sight to these sources, using nonparametric methods. Apparent flux is estimated from the ratio of the source count rate to the instrumental effective area averaged over the chosen band. Absorption, intrinsic flux, and errors on these quantities are estimated from comparison of source photometric quantities with those of high signal-to-noise spectra that were simulated using spectral models characteristic of the class of astrophysical sources under study. The concept of this method is similar to the long-standing use of color-magnitude diagrams in optical and infrared astronomy, with X-ray median energy replacing color index and X-ray source counts replacing magnitude. Our nonparametric method is tested against the apparent spectra of ~2000 faint sources in the Chandra observation of the rich young stellar cluster in the M 17 H II region. We show that the intrinsic X-ray properties can be determined with little bias and reasonable accuracy using these observable photometric quantities without employing often uncertain and time-consuming methods of nonlinear parametric spectral modeling. Our method is calibrated for thermal spectra characteristic of stars in young stellar clusters, but recalibration should be possible for some other classes of faint X-ray sources such as extragalactic active galactic nuclei.

Getman, Konstantin V.; Feigelson, Eric D.; Broos, Patrick S.; Townsley, Leisa K.; Garmire, Gordon P.

2010-01-01

207

Nonparametric Estimation of Intrinsic Properties of Faint X-ray Sources  

NASA Astrophysics Data System (ADS)

X-ray sources with very few counts can be identified with low-noise X-ray detectors such as the Advanced CCD Imaging Spectrometer onboard the Chandra X-ray Observatory. These sources are often too faint for parametric spectral modeling using well-established methods such as spectral fitting with XSPEC. We discuss the estimation of apparent and intrinsic broad-band X-ray fluxes and soft X-ray absorption from gas along the line-of-sight to these sources, using nonparametric methods. Apparent flux is estimated from the ratio of the source count number to the instrumental effective area averaged over the chosen band. Absorption and intrinsic flux are estimated from the comparison of the apparent median energy of the source photons and apparent source flux with those of high signal-to-noise spectra that were simulated using spectral models characteristic of much brighter sources of similar class previously studied in detail. The concept of this method is similar to the long-standing use of color-magnitude diagrams in optical and infrared astronomy. Our nonparametric method is tested against the apparent spectra of faint sources. We show that the intrinsic X-ray properties can be determined with little bias and reasonable accuracy using these observable photometric quantities without employing often uncertain methods of non-linear parametric spectral modeling. Our results are obtained for thermal spectra characteristic of stars in young stellar clusters, but similar results should hold for other classes of faint X-ray sources.

Getman, Konstantin; Feigelson, Eric; Broos, Patrick; Townsley, Leisa; Garmire, Gordon

2009-09-01

208

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

209

The nature of faint emission-line galaxies  

NASA Technical Reports Server (NTRS)

One of the results of faint galaxy redshift surveys is the increased fraction of galaxies which have strong emission-line spectra. These faint surveys find that roughly 50 percent of the galaxies have an equivalent width of (OII), W sub 3727, greater than 20 A while this fraction is less than 20 percent in the DARS survey. This has been interpreted as evidence for strong evolution in the galaxy population at redshifts less than 0.5. In order to further investigate the properties of the galaxies in faint redshift surveys, two important factors must be addressed. The first is the observed correlation between color, luminosity, and W sub 3727. There is a correlation between color and the strength of emission lines, bluer galaxies having stronger emission features, as evident for Markarian galaxies and for galaxies in Kennicutt's spectrophotometric atlas. This correlation also applies galaxies in faint redshift surveys. In addition, low luminosity galaxies have a larger average W sub 3727 (and bluer colors) than higher luminosity galaxies. This is illustrated for Kennicutt's low z late-type galaxies, for the Durham Faint Surveys, and for galaxies in SA68. The second factor which must be incorporated into any interpretation of the faint emission galaxies is the different luminosity functions for galaxies depending on color. This is usually modeled by varying M* for different color classes (or morphological types); however, the shape of the luminosity function is different for galaxies with different colors. Low luminosity, blue galaxies have a much larger number density than low luminosity, red galaxies. Furthermore, the low luminosity end of the blue galaxy luminosity function is not well fit by a Schechter function. These two factors have been included in a very simple, no-evolution, model for the galaxy population. This model uses the luminosity functions from Shanks (1990) and spectral energy distributions (SED's) from Bruzual (1988). W sub 3727 is predicted using the correlation (including dispersion) with color.

Smetanka, John J.

1993-01-01

210

A sensitive search for CO emission from faint blue galaxies at z~0.5  

E-print Network

We have obtained sensitive upper limits on the CO J=2-1 and CO J=3-2 emission lines for five faint blue galaxies with redshifts $z\\sim 0.5$ using the IRAM 30~m telescope. These observations would have been able to detect the luminous infrared galaxy IRAS F10214+4724 if it were located at this redshift and unlensed. However, they are not sensitive enough to detect the prototype starburst galaxy M82 or the HII galaxy UM448 if they were located at this redshift. Our upper limits for the CO emission are consistent with between 19% and 66% of the total galactic mass being in the form of molecular hydrogen, and thus shed little light on the ultimate fate of these galaxies.

C. D. Wilson; F. Combes

1997-10-06

211

Exploring the Faint End of the Luminosity-Metallicity Relation with H? Dots  

NASA Astrophysics Data System (ADS)

The well-known correlation between a galaxy's luminosity and its gas-phase oxygen abundance (the luminosity-metallicity (L-Z) relation) offers clues toward our understanding of chemical enrichment histories and evolution. Bright galaxies are comparatively better studied than faint ones, leaving a relative dearth of observational data points to constrain the L-Z relation in the low-luminosity regime. We present high S/N nebular spectroscopy of low-luminosity star-forming galaxies observed with the KPNO 4m using the new KOSMOS spectrograph to derive direct-method metallicities. Our targets are strong point-like emission-line sources discovered serendipitously in continuum-subtracted narrowband images from the ALFALFA H? survey. Follow-up spectroscopy of these "H? dots" shows that these objects represent some of the lowest luminosity star-forming systems in the local Universe. Our KOSMOS spectra cover the full optical region and include detection of [O III] ?4363 in roughly a dozen objects. This paper presents some of the first scientific results obtained using this new spectrograph, and demonstrates its capabilities and effectiveness in deriving direct-method metallicities of faint objects.

Hirschauer, Alec S.; Salzer, John J.

2015-01-01

212

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. PMID:23837000

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

2013-01-01

213

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

214

Cataclysmic Variables from the Faint Sky Variability Survey  

Microsoft Academic Search

The Faint Sky Variability Survey is a large, deep field, optical, photometric survey using the Wide-Field Camera at the Isaac Newton Telescope on La Palma. Approximately 18 square degrees have been observed photometrically in BVI colors with variability sampling of 10's of minutes to years. Current population synthesis models for cataclysmic variables (CVs) predict the majority (70%) have passed the

M. E. Huber; S. B. Howell

2001-01-01

215

Spectroscopic Observations of Twenty-one Faint Cataclysmic Variables Candidates  

E-print Network

We provide the first minimum light spectroscopic observations for 21 previously known or suspected faint cataclysmic variable candidates. The sources were selected from the Downes et al. (2001) living edition catalog and the identified candidates have minimum light magnitudes of V~18-22. We confirm 15 of the candidates to be cataclysmic variables.

E. Mason; S. B. Howell

2003-03-03

216

CONFIRMATION OF FAINT DWARF GALAXIES IN THE M81 GROUP  

SciTech Connect

We have followed up on the results of a 65 deg{sup 2} CFHT/MegaCam imaging survey of the nearby M81 Group searching for faint and ultra-faint dwarf galaxies. The original survey turned up 22 faint candidate dwarf members. Based on two-color HST ACS/WFC and WFPC2 photometry, we now confirm 14 of these as dwarf galaxy members of the group. Distances and stellar population characteristics are discussed for each. To a completeness limit of M{sub r{sup '}}= -10, we find a galaxy luminosity function slope of –1.27 ± 0.04 for the M81 Group. In this region, there are now 36 M81 Group members known, including 4 blue compact dwarfs; 8 other late types including the interacting giants M81, NGC 3077, and M82; 19 early type dwarfs; and at least 5 potential tidal dwarf galaxies. We find that the dSph galaxies in M81 appear to lie in a flattened distribution, similar to that found for the Milky Way and M31. One of the newly discovered dSph galaxies has properties similar to the ultra-faint dwarfs being found in the Local Group with a size R{sub e} ? 100 pc and total magnitude estimates M{sub r{sup '}}= -6.8 and M{sub I} ? –9.1.

Chiboucas, Kristin [Gemini Observatory, 670 North A'ohoku Pl, Hilo, HI 96720 (United States); Jacobs, Bradley A.; Tully, R. Brent [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96821 (United States); Karachentsev, Igor D., E-mail: kchibouc@gemini.edu, E-mail: bjacobs@ifa.hawaii.edu, E-mail: tully@ifa.hawaii.edu, E-mail: ikar@luna.sao.ru [Special Astrophysical Observatory (SAO), Russian Academy of Sciences, Nizhnij Arkhyz, Karachai-Cherkessian Republic 369167 (Russian Federation)

2013-11-01

217

1. Dyea Dock looking south. Note faint evenly spaced circular ...  

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

1. Dyea Dock looking south. Note faint evenly spaced circular dark pieces of grass up through the middle of the picture indicating posts making up the pier. Photograph made from park service cherry picker. - Dyea Dock & Association (Ruins), Skagway, Skagway, AK

218

On the relation of mid-infrared emission with the gamma-ray properties of Fermi-detected BL Lac objects  

NASA Astrophysics Data System (ADS)

We present the Wide-field Infrared Survey Explorer (WISE) photometric data of 158 Fermi-detected BL Lacs and investigate the nature of their mid-infrared (MIR) continuum emission. In the [3.4]-[4.6]-[12] ?m color-color diagram, nearly all their colors lie within the WISE Blazar strip (WBS), which is an effective diagnostic tool to separate sources dominated by non-thermal radiation from those dominated by thermal radiation. This feature indicates that their MIR emission is predominantly non-thermal. This argument is further supported by the strong radio-MIR flux correlation. We derive their MIR spectral indices and compare them with the near-infrared (NIR) spectral indices. We find that there is a prevalent steepening from MIR spectrum to NIR spectrum. The low-frequency-peaked BL Lacs (LBLs) have on average a larger MIR spectral index and a higher MIR luminosity than the high-frequency-peaked BL Lacs (HBLs), and the intermediate-frequency-peaked BL Lacs (IBLs) appear to bridge them. The MIR- ?-ray flux correlation is highly significant. A strong positive correlation is also found between the MIR and ?-ray spectral indices. The ?-ray-MIR loudness is significantly correlated with the synchrotron peak frequency. Finally we propose that the ?-rays are highly associated with the MIR emission from the jet, and the ?-ray emission is likely from the synchrotron self-Compton process for the Fermi-detected BL Lacs in our sample.

Mao, Li-Sheng

2012-08-01

219

The Infrared Sky.  

ERIC Educational Resources Information Center

The Infrared Astronomical Satellite (IRAS) is a survey instrument that has provided an overall view of the infrared sky and identified objects that merit further investigation. A description of the IRAS and examples of the types of astronomical data collected are presented. (JN)

Habing, Harm J.; Neugebauer, Gerry

1984-01-01

220

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

221

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

222

Strong Near-Infrared Emission Interior to the Dust-Sublimation Radius of Young Stellar Objects MWC275 and AB Aur  

E-print Network

Using the longest optical-interferometeric baselines currently available, we have detected strong near-infrared (NIR) emission from inside the dust-destruction radius of Herbig Ae stars MWC275 and AB Aur. Our sub-milli-arcsecond resolution observations unambiguously place the emission between the dust-destruction radius and the magnetospheric co-rotation radius. We argue that this new component corresponds to hot gas inside the dust-sublimation radius, confirming recent claims based on spectrally-resolved interferometry and dust evaporation front modeling.

A. Tannirkulam; J. D. Monnier; R. Millan-Gabet; T. J. Harries; E. Pedretti; T. A. ten Brummelaar; H. McAlister; N. Turner; J. Sturmann; L. Sturmann

2008-03-10

223

Verification of mesoscale objective analyses of VAS and rawinsode data using the March 1982 AVE/VAS special network data. [Atmospheric Variability Experiment/Visible-infrared spin-scan radiometer Atmospheric Sounder  

NASA Technical Reports Server (NTRS)

Various combinations of VAS (Visible and Infrared Spin Scan Radiometer Atmospheric Sounder) data, conventional rawinsonde data, and gridded data from the National Weather Service's (NWS) global analysis, were used in successive-correction and variational objective-analysis procedures. Analyses are produced for 0000 GMT 7 March 1982, when the VAS sounding distribution was not greatly limited by the existence of cloud cover. The successive-correction (SC) Procedure was used with VAS data alone, rawinsonde data alone, and both VAS and rawinsonde data. Variational techniques were applied in three ways. Each of these techniques was discussed.

Doyle, James D.; Warner, Thomas T.

1988-01-01

224

Catalog of infrared observations  

NASA Technical Reports Server (NTRS)

The infrared astronomical data base and its principal data product, the catalog of Infrared Observations (CIO), comprise a machine readable library of infrared (1 microns to 1000 microns astronomical observations. To date, over 1300 journal articles and 10 major survey catalogs are included in this data base, which contains about 55,000 individual observations of about 10,000 different infrared sources. Of these, some 8,000 sources are identifiable with visible objects, and about 2,000 do not have known visible counterparts.

Gezari, D. Y.; Schmitz, M.; Mead, J. M.

1982-01-01

225

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

226

The Electromagnetic Spectrum: Infrared Waves  

NSDL National Science Digital Library

This webpage, part of a NASA site on the electromagnetic spectrum, presents information on infrared light. An explanation of how objects emit infrared is provided, along with a diagram of the electromagnetic spectrum. The site contains a number of photos made with infrared light.

2007-06-24

227

CCD time-resolved photometry of faint cataclysmic variables. IV  

Microsoft Academic Search

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

Steve B. Howell; DANUTA Dobrzycka; PAULA Szkody; Tobias J. Kreidl

1991-01-01

228

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

229

Two-photon processes in faint biphoton fields  

Microsoft Academic Search

The goal of this research is to determine and study a physical system that will enable a fast and intrinsically two-photon detector, which would be of interest for quantum information and metrology applications. We consider two types of two-photon processes that can be observed using a very faint, but quantum-correlated biphoton field. These are optical up-conversion and an external photoelectric

Dmitry V. Strekalov; Matthew C. Stowe; Maria V. Chekhova; Jonathan P. Dowling

2002-01-01

230

Do the lensing cross-sections of faint galaxies cover the whole sky ?  

E-print Network

Very deep galaxy surveys have revealed a considerably large population of faint galaxies, which leads to the speculation that all distant objects are moderately magnified by the gravitational lensing effects of galaxies (Fried 1997). In this letter, we present a simple estimate of the lensing amplitudes by all galaxies up to redshift $z=2$ in terms of galaxy merging and answer the question whether the sky is fully covered by the lensing cross-sections of galaxies. It is shown that, as a result of the combination of the increase of galaxy number density and the decrease of galaxy velocity dispersion with lookback time, less than $\\sim1/10$ of the sky to $z=2$ can be moderately affected by galaxies acting as lenses with magnification $\\mu>1.1$. This conclusion is independent of the galaxy limiting magnitude. In other words, no matter how high the surface number density of faint galaxies becomes, it is unlikely that their lensing cross-sections of $\\mu>1.1$ can cover the whole sky.

Zong-Hong Zhu; Xiang-Ping Wu

1997-04-22

231

THE ABUNDANCE GRADIENT IN THE EXTREMELY FAINT OUTER DISK OF NGC 300  

SciTech Connect

In an earlier work, we showed for the first time that the resolved stellar disk of NGC 300 is very extended with no evidence for truncation, a phenomenon that has since been observed in other disk galaxies. We revisit the outer disk of NGC 300 in order to determine the metallicity of the faint stellar population. With the Gemini Multi Object Spectrograph camera at Gemini South, we reach 50% completeness at (g', i') = (26.8-27.4, 26.1-27.0) in photometric conditions and 0.''7 seeing. At these faint depths, careful consideration must be given to the background galaxy population. The mean colors of the outer disk stars fall within the spread of colors for the background galaxies, but the stellar density dominates the background galaxies by {approx}2:1. The predominantly old stellar population in the outer disk exhibits a negative abundance gradient-as expected from models of galaxy evolution-out to about 10 kpc where the abundance trend changes sign. We present two scenarios to explain the flattening, or upturn, in the metallicity gradient of NGC 300 and discuss the implication this has for the broader picture of galaxy formation.

Vlajic, M. [Astrophysics, Department of Physics, Keble Road, University of Oxford, Oxford OX1 3RH (United Kingdom); Bland-Hawthorn, J. [Institute of Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Freeman, K. C. [Mount Stromlo Observatory, Private Bag, Woden, ACT 2611 (Australia)], E-mail: vlajic@astro.ox.ac.uk

2009-05-20

232

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

SciTech Connect

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

Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter, E-mail: siegel@astro.psu.ed, E-mail: hoversten@astro.psu.ed, E-mail: roming@astro.psu.ed, E-mail: brown@astro.psu.ed [Department of Astronomy, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2010-12-10

233

Performance of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) high-resolution near-infrared multi-object fiber spectrograph  

NASA Astrophysics Data System (ADS)

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) uses a dedicated 300-fiber, narrow-band near-infrared (1.51-1.7 ?m), high resolution (R~22,500) spectrograph to survey approximately 100,000 giant stars across the Milky Way. This three-year survey, in operation since late-summer 2011 as part of the Sloan Digital Sky Survey III (SDSS III), will revolutionize our understanding of the kinematical and chemical enrichment histories of all Galactic stellar populations. We present the performance of the instrument from its first year in operation. The instrument is housed in a separate building adjacent to the 2.5-m SDSS telescope and fed light via approximately 45-meter fiber runs from the telescope. The instrument design includes numerous innovations including a gang connector that allows simultaneous connection of all fibers with a single plug to a telescope cartridge that positions the fibers on the sky, numerous places in the fiber train in which focal ratio degradation had to be minimized, a large mosaic-VPH (290 mm x 475 mm elliptically-shaped recorded area), an f/1.4 six-element refractive camera featuring silicon and fused silica elements with diameters as large as 393 mm, three near-infrared detectors mounted in a 1 x 3 mosaic with sub-pixel translation capability, and all of these components housed within a custom, LN2-cooled, stainless steel vacuum cryostat with dimensions 1.4-m x 2.3-m x 1.3-m.

Wilson, John C.; Hearty, F.; Skrutskie, M. F.; Majewski, S. R.; Schiavon, R.; Eisenstein, D.; Gunn, J.; Holtzman, J.; Nidever, D.; Gillespie, B.; Weinberg, D.; Blank, B.; Henderson, C.; Smee, S.; Barkhouser, R.; Harding, A.; Hope, S.; Fitzgerald, G.; Stolberg, T.; Arns, J.; Nelson, M.; Brunner, S.; Burton, A.; Walker, E.; Lam, C.; Maseman, P.; Barr, J.; Leger, F.; Carey, L.; MacDonald, N.; Ebelke, G.; Beland, S.; Horne, T.; Young, E.; Rieke, G.; Rieke, M.; O'Brien, T.; Crane, J.; Carr, M.; Harrison, C.; Stoll, R.; Vernieri, M.; Shetrone, M.; Allende-Prieto, C.; Johnson, J.; Frinchaboy, P.; Zasowski, G.; Garcia Perez, A.; Bizyaev, D.; Cunha, K.; Smith, V. V.; Meszaros, Sz.; Zhao, B.; Hayden, M.; Chojnowski, S. D.; Andrews, B.; Loomis, C.; Owen, R.; Klaene, M.; Brinkmann, J.; Stauffer, F.; Long, D.; Jordan, W.; Holder, D.; Cope, F.; Naugle, T.; Pfaffenberger, B.; Schlegel, D.; Blanton, M.; Muna, D.; Weaver, B.; Snedden, S.; Pan, K.; Brewington, H.; Malanushenko, E.; Malanushenko, V.; Simmons, A.; Oravetz, D.; Mahadevan, S.; Halverson, S.

2012-09-01

234

An infrared study of the bipolar outflow region GGD 12-15  

NASA Technical Reports Server (NTRS)

Infrared observations from 1 to 100 microns are presented for the region associated with a bipolar CO outflow source near the nebulous objects GGD 12 to 15. A luminous far-infrared source was found associated with a radio-continuum source in the area. This object appears to be a compact HII region around a nearly main-sequence BO star. A faint 20 micron source was also discovered at the position of an H2O maser 30 deg northwest of the HII region. This object appears to be associated with but not coincident with a 2 micron reflection nebula. This structure serves as evidence for a non-spherically symmetric, possibly disk-like dust distribution around the exciting star for the maser. This object probably powers the bi-polar CO outflow although its luminosity is less than 10 percent that of the star which excites the compact HII region. A number of other 2 micron sources found in the area are probably members of a recently formed cluster.

Harvey, P. M.; Wilking, B. A.; Joy, M.; Lester, D. F.

1985-01-01

235

An infrared study of the bi-polar outflow region GGD 12-15  

NASA Technical Reports Server (NTRS)

Infrared observations from 1 to 100 microns are presented for the region associated with a bipolar CO outflow source near the nebulous objects GGD 12 to 15. A luminous far-infrared source was found associated with a radio-continuum source in the area. This object appears to be a compact HII region around a nearly main-sequence BO star. A faint 20 micron source was also discovered at the position of an H2O maser 3O deg northwest of the HII region. This object appears to be associated with but not coincident with a 2 micron reflection nebula. This structure serves as evidence for a non-spherically symmetric, possibly disk-like dust distribution around the exciting star for the maser. This object probably powers the bi-polar CO outflow although its luminosity is less than 10% that of the star which excites the compact HII region. A number of other 2 micron sources found in the area are probably members of a recently formed cluster.

Harvey, P. M.; Wilking, B. A.; Joy, M.; Lester, D. F.

1984-01-01

236

The Nature of Faint 24 Micron Sources Seen in Spitzer Space Telescope Observations of ELAIS-N1  

NASA Astrophysics Data System (ADS)

The Spitzer Space Telescope has undertaken the deepest ever observations of the 24 ?m sky in the European Large Area ISO Survey (ELAIS-N1) field, with the Multiband Imaging Photometer (MIPS) instrument, as part of GOODS Science Verification observations. We present completeness-corrected extragalactic source counts down to 24 ?m flux densities of 20 ?Jy (30% completeness), a factor of 10,000 more sensitive than IRAS. The shape of the counts confirms model predictions for a strong evolution of the infrared luminosity function between redshifts of 0 and 1 and suggests a flattening in the evolutionary parameters at higher redshifts. Models that fit the counts indicate that luminous infrared galaxies [1011LsolarInfrared Array Camera (IRAC) 3.6 and 4.5 ?m near-infrared channels, consistent with the expected spectral energy distribution of infrared luminous galaxies at moderate redshift. The similarity between the observed mid-infrared to near-infrared flux ratios of the Spitzer-detected sources and the 15 ?m/HK-band flux ratios of the ISOCAM 15 ?m sources seen in the Hubble Deep Field-North strongly suggests that faint 24 ?m sources are high-redshift analogs of ISOCAM 15 ?m sources and that they have the potential to provide an evolutionary connection between the well-studied z~3 Lyman break galaxy population and the dusty starburst galaxies seen at z~1.

Chary, R.; Casertano, S.; Dickinson, M. E.; Ferguson, H. C.; Eisenhardt, P. R. M.; Elbaz, D.; Grogin, N. A.; Moustakas, L. A.; Reach, W. T.; Yan, H.

2004-09-01

237

Infrared Investigations  

NSDL National Science Digital Library

In this activity, learners explore how infrared technology is used by engineers to create equipment and systems for a variety of industries. Learners explore the application of infrared in remote controls, test materials that encourage or prevent infrared transmission, and develop systems that allow transmission of infrared in restricted environments.

Ieee

2013-08-30

238

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

239

Near-Infrared Spectra and the Evolutionary Status of Young Stellar Objects: Results of a 1.1-2.4 (??) Survey  

Microsoft Academic Search

We present the results of a moderate resolution (R˜500) 1.15-2.42 mum near-IR spectroscopic survey of young stellar objects (YSOs), FU Ori type stars, and MK spectral standards. The survey sample includes approximately 100 mostly low-mass YSOs characterized by a wide range of spectral energy distributions (SEDs) and evolutionary states which are drawn from the Ophiuchus, Taurus, and other nearby star

Thomas P. Greene; Charles J. Lada

1996-01-01

240

The Evolving Faint-End of the Luminosity Function  

E-print Network

We investigate the evolution of the faint-end slope of the luminosity function, $\\alpha$, using semi-analytical modeling of galaxy formation. In agreement with observations, we find that the slope can be fitted well by $\\alpha (z) =a+b z$, with a=-1.13 and b=-0.1. The main driver for the evolution in $\\alpha$ is the evolution in the underlying dark matter mass function. Sub-L_* galaxies reside in dark matter halos that occupy a different part of the mass function. At high redshifts, this part of the mass function is steeper than at low redshifts and hence $\\alpha$ is steeper. Supernova feedback in general causes the same relative flattening with respect to the dark matter mass function. The faint-end slope at low redshifts is dominated by field galaxies and at high redshifts by cluster galaxies. The evolution of $\\alpha(z)$ in each of these environments is different, with field galaxies having a slope b=-0.14 and cluster galaxies b=-0.05. The transition from cluster-dominated to field-dominated faint-end slope occurs roughly at a redshift $z_* \\sim 2$, and suggests that a single linear fit to the overall evolution of $\\alpha(z)$ might not be appropriate. Furthermore, this result indicates that tidal disruption of dwarf galaxies in clusters cannot play a significant role in explaining the evolution of $\\alpha(z)$ at z< z_*. In addition we find that different star formation efficiencies a_* in the Schmidt-Kennicutt-law and supernovae-feedback efficiencies $\\epsilon$ generally do not strongly influence the evolution of $\\alpha(z)$.

S. Khochfar; J. Silk; R. A. Windhorst; R. E. Ryan Jr

2007-09-03

241

CCD time-resolved photometry of faint cataclysmic variables. III  

NASA Technical Reports Server (NTRS)

CCD time-resolved photometry in V, B, and near-IR for 17 faint cataclysmic variables (CVs) is presented and analyzed. The data are obtained at Kitt Peak National Observatory, the Perkins reflector, Lowell Observatory, and the Observatorio del Roque de los Muchachos from April-June 1989. The degree of variability and periodicities for the CVs are examined. It is observed that the variability of most of the stars is consistent with CV class behavior. Orbital periods for five CVs are determined, and three potential eclipsing systems are detected.

Howell, Steve B.; Szkody, Paula; Kreidl, Tobias J.; Mason, Keith O.; Puchnarewicz, E. M.

1990-01-01

242

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

243

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

244

Image quality evaluation of infrared image  

Microsoft Academic Search

According to the imaging procedure an infrared picture include an object image, a background image and a noise image. The object image and the background image are main body of an infrared image; noise image is the disturbance on the main body. This paper discusses the infrared image quality from three aspects: information capacity, image detail and pseudo-s\\/n ratio, it

Chun-mei Xu; Gang Li; Wengang Hu; Wei Zhang

2005-01-01

245

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

246

Infrared stars in binary systems  

NASA Technical Reports Server (NTRS)

The peculiar F-type supergiant HD 101584, which has a large and unusual infrared excess, is discussed along with the possibility that the infrared radiation could be accounted for by a cool companion. The peculiar F supergiants 89 Her, v Sgr, and R CrB are also considered as possible binary systems containing an infrared star. It is pointed out that all four of these stars have infrared excesses with characteristics similar to the infrared radiation from several cool objects which are known single stars.

Humphreys, R. M.; Ney, E. P.

1974-01-01

247

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

248

Infrared spectrum of an extremely cool white-dwarf star  

PubMed

White dwarfs are the remnant cores of stars that initially had masses of less than 8 solar masses. They cool gradually over billions of years, and have been suggested to make up much of the 'dark matter' in the halo of the Milky Way. But extremely cool white dwarfs have proved difficult to detect, owing to both their faintness and their anticipated similarity in colour to other classes of dwarf stars. Recent improved models indicate that white dwarfs are much more blue than previously supposed, suggesting that the earlier searches may have been looking for the wrong kinds of objects. Here we report an infrared spectrum of an extremely cool white dwarf that is consistent with the new models. We determine the star's temperature to be 3,500 +/- 200 K, making it the coolest known white dwarf. The kinematics of this star indicate that it is in the halo of the Milky Way, and the density of such objects implied by the serendipitous discovery of this star is consistent with white dwarfs dominating the dark matter in the halo. PMID:10638748

Hodgkin; Oppenheimer; Hambly; Jameson; Smartt; Steele

2000-01-01

249

Adaptive Optics Imaging Survey of Luminous Infrared Galaxies  

E-print Network

We present high resolution imaging observations of a sample of previously unidentified far-infrared galaxies at z < 0.3. The objects were selected by cross-correlating the IRAS Faint Source Catalog with the VLA FIRST catalog and the HST Guide Star Catalog to allow for adaptive optics observations. We found two new ULIGs (with L_FIR equal to or greater than 10^{12} L_sun) and 19 new LIGs (with L_FIR equal to or greater than 10^{11} L_sun). Twenty of the galaxies in the sample were imaged with either the Lick or Keck adaptive optics systems in H or K'. Galaxy morphologies were determined using the two dimensional fitting program GALFIT and the residuals examined to look for interesting structure. The morphologies reveal that at least 30% are involved in tidal interactions, with 20% being clear mergers. An additional 50% show signs of possible interaction. Line ratios were used to determine powering mechanism; of the 17 objects in the sample showing clear emission lines - four are active galactic nuclei and seven are starburst galaxies. The rest exhibit a combination of both phenomena.

Edward A. Laag; Gabriela Canalizo; Wil van Breugel; Elinor L. Gates; Wim de Vries; S. Adam Stanford

2006-03-15

250

Early-stage star-forming cloud cores in Galactic Legacy Infrared Mid-Plane Survey (GLIMPSE) extended green objects (EGOs) as traced by organic species  

NASA Astrophysics Data System (ADS)

In order to investigate the physical and chemical properties of massive star-forming cores in the early stages, we analyse the excitation and abundance of four organic species, CH3OH, CH3OCH3, HCOOCH3 and CH3CH2CN, towards 29 extended green object (EGO) cloud cores that were observed by our previous single-dish spectral line survey. The EGO cloud cores are found to have similar methanol J3-J2 rotation temperatures of ˜44 K, a typical linear size of ˜0.036 pc and a typical beam-averaged methanol abundance of several 10-9 (the beam-corrected value could reach several 10-7). The abundances of the latter three species, normalized by that of methanol, are also found to be correlated across a large variety of clouds such as EGO cloud cores, hot corinos, massive hot cores and Galactic Centre clouds. The chemical properties of the EGO cloud cores lie between those of hot cores and hot corinos. However, the abundances and abundance ratios of the four species cannot be explained satisfactorily by recent chemical models, either among EGO cloud cores or among the various types of cloud core from literature.

Ge, J. X.; He, J. H.; Chen, X.; Takahashi, S.

2014-12-01

251

Physical Characteristics of Faint Meteors by Light Curve and High-resolution Observations  

NASA Astrophysics Data System (ADS)

The physical structure of a meteoroid may be inferred from optical observations, particularly the light curve, of a meteor. For example: a classically shaped (late peaked) light curve is seen as evidence of a solid single body, whereas a symmetric light curve may indicate a dustball structure. High-resolution optical observations show how the meteoroid fragments: continuously, leaving a long wake, or discretely, leaving several distinct pieces. Calculating the orbit of the meteoroid using two station data then allows the object to be associated with asteroidal or cometary parent bodies. Optical observations thus provide simultaneous information on meteoroid structure, fragmentation mode, and origin.CAMO (the Canadian Automated Meteor Observatory) has been continuously collecting faint (masses < 10-4 kg) two station optical meteors with image-intensified narrow field (with a resolution of up to 3 meters per pixel) and wide field (26 by 19 degrees) cameras since 2010. The narrow field, telescopic cameras allow the meteor fragmentation to be studied using a pair of mirrors to track the meteor. The wide-field cameras provide the light curve and trajectory solution.We present preliminary results from classifying light curves and high-resolution optical observations for 3000 faint meteors recorded since 2010. We find that most meteors (both asteroidal and cometary) show long trails, while meteors with short trails are the second most common morphology. It is expected that meteoroids that experience negligible fragmentation have the shortest trails, so our results imply that the majority of small meteoroids fragment during ablation. A surprising observation is that almost equal fractions of asteroidal and cometary meteors fragment (showing long trails), implying a similar structure for both types of meteoroids.

Subasinghe, Dilini; Campbell-Brown, Margaret D.; Stokan, Edward

2014-11-01

252

Characterizing Faint Galaxies in the Reionization Epoch: LBT Confirms Two L < 0.2 Lsstarf Sources at z = 6.4 Behind the CLASH/Frontier Fields Cluster MACS0717.5+3745  

NASA Astrophysics Data System (ADS)

We report the LBT/MODS1 spectroscopic confirmation of two images of faint Ly? emitters at z = 6.4 behind the Frontier Fields galaxy cluster MACSJ0717.5+3745. A wide range of lens models suggests that the two images are highly magnified, with a strong lower limit of ? > 5. These are the faintest z > 6 candidates spectroscopically confirmed to date. These may also be multiple images of the same z = 6.4 source as supported by their similar intrinsic properties, but the lens models are inconclusive regarding this interpretation. To be cautious, we derive the physical properties of each image individually. Thanks to the high magnification, the observed near-infrared (restframe ultraviolet) part of the spectral energy distributions and Ly? lines are well detected with S/N(m 1500) >~ 10 and S/N(Ly?) ~= 10-15. Adopting ? > 5, the absolute magnitudes, M 1500, and Ly? fluxes are fainter than -18.7 and 2.8 × 10-18 erg s-1 cm-2, respectively. We find a very steep ultraviolet spectral slope ? = -3.0 ± 0.5 (F ? = ??), implying that these are very young, dust-free, and low metallicity objects, made of standard stellar populations or even extremely metal poor stars (age <~ 30 Myr, E(B - V) = 0 and metallicity 0.0-0.2 Z/Z ?). The objects are compact (<1 kpc2) and with a stellar mass M sstarf < 108 M ?. The very steep ?, the presence of the Ly? line, and the intrinsic FWHM (<300 km s-1) of these newborn objects do not exclude a possible leakage of ionizing radiation. We discuss the possibility that such faint galaxies may resemble those responsible for cosmic reionization. The Large Binocular Telescope (LBT) is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University; and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

Vanzella, E.; Fontana, A.; Zitrin, A.; Coe, D.; Bradley, L.; Postman, M.; Grazian, A.; Castellano, M.; Pentericci, L.; Giavalisco, M.; Rosati, P.; Nonino, M.; Smit, R.; Balestra, I.; Bouwens, R.; Cristiani, S.; Giallongo, E.; Zheng, W.; Infante, L.; Cusano, F.; Speziali, R.

2014-03-01

253

The Sakurai Object: A Case Study in Advanced Stellar Evolution  

Microsoft Academic Search

In 1996 Y. Sakurai, a Japanese amateur astronomer, discovered what was originally described as a nova in Sagittarius. Spectroscopy soon after discovery indicated the Sakurai Object to have a cool hydrogen-deficient photosphere -quite unlike that of a normal nova explosion- and the only similar object being Nova Aql 1919 (Lundmark, 1921). With the detection of a faint and ancient planetary

P. Pollacco

2000-01-01

254

Mass influx obtained from LLLTV observations of faint meteors  

NASA Technical Reports Server (NTRS)

Since the advent of low light level television (LLLTV) systems, it has been recognized that such devices offer the ability to observe meteors as faint as 10th magnitude which allows the extension of optical meteor data to masses as small as 0.0001 grams. The Space Sciences Lab at Marshall Space Flight Center has been actively engaged in such observations using image orthicons and intensified SEC vidicons. The results of these observations are presented along with an interpretation in terms of mass-flux. This interpretation includes the development of a relationship between peak luminosity of a meteor and mass, velocity, and zenith angle that was derived from single body meteor theory and compares favorably with results obtained from the Artificial Program. Also included in the mass flux interpretation is an analysis of the observation response of a LLLTV system to fixed and moving point sources.

Naumann, R. J.; Clifton, K. S.

1972-01-01

255

GPU-accelerated Faint Streak Detection for Uncued Surveillance of LEO  

NASA Astrophysics Data System (ADS)

By astronomical standards, small objects (<10cm) in LEO illuminated by the Sun under terminator conditions are quite bright, depositing 100's to 1000's of photons per second into small telescope apertures (< 1m diameter). The challenge in discovering these objects with no a priori knowledge of their orbit (i.e. uncued surveillance) is that their relative motion with respect to a ground-based telescope makes them appear to have large angular rates of motion, up to and exceeding 1 degree per second. Thus in even a short exposure, the signal from the object is smeared out in a streak with low signal-to-noise per pixel. Go Green Termite (GGT), Inc. of Gilroy, CA, in collaboration with the University of New Mexico (UNM), is building two proof-of-concept wide-field imaging systems to test, develop and prove a novel streak detection technique. The imaging systems are built from off-the-shelf optics and detectors resulting in a 350mm aperture and a 6 square degree field of view. For streak detection, field of view is of critical importance because the maximum exposure time on the object is limited by its crossing time. In this way, wider fields of view impact surveys for LEO objects both by increasing the survey volume and increasing sensitivity. Using our newly GPU-accelerated detection scheme, the proof-of-concept systems are expected to be able to detect objects fainter than 12th magnitude moving at 1 degree per second and possibly as faint as 13th magnitude for slower moving objects. Meter-class optical systems using these techniques should be able to detect objects fainter than 14th magnitude, which is roughly equivalent to a golf ball at 1000km altitude. The goal of this work is to demonstrate a scalable system for near real time detection of fast moving objects that can be then handed off to other instruments capable of tracking and characterizing them. The two proof-of-concept systems, separated by ~30km, work together by taking simultaneous images of the same volume to constrain the orbits of detected objects using parallax measurements. These detections will then be followed-up by photometric observations taken at UNM to independently assess the objects and the quality of the derived orbits. We believe this will demonstrate the potential of small telescope arrays for detecting and cataloguing heretofore unknown LEO objects.

Zimmer, P.; Ackermann, M.; McGraw, J. T.

2013-09-01

256

An Improved Technique for the Photometry and Astrometry of Faint Companions  

E-print Network

An Improved Technique for the Photometry and Astrometry of Faint Companions DANIEL BURKE School to differential astrometry and photometry of faint companions in adap- tive optics images. It is based ratio (SR) data (SR 0:5), the differential photometry of a binary star with a m ¼ 4:5 and a separation

Dainty, Chris

257

The atmospheric trajectories of faint meteors according to observations using an image converter  

NASA Astrophysics Data System (ADS)

An image-converter camera at the Physico-technical Institute of the Turkmen Academy of Sciences was used to study the trajectories of faint meteors. These data were used to compile a catalog of radiants, heights, velocities, and angular lengths of faint meteors observed from 1977 to 1981.

Ovezgel'Dyev, O. G.; Shafiev, R. I.; Mukhamednazarov, S.

258

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.

259

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

260

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

261

Infrared instrumentation for large telescopes: an alternative approach  

E-print Network

I very briefly describe the latest generation near infrared (1-2.5 micron) instruments which are available on, or under development for `large' (D>=3.5 m) telescopes. Most of the imagers under construction are limited to relatively small fields, while the spectrometers aim at quite high resolving powers. The alternative instruments which I discuss here are - WIDE, a relatively low-cost instrument for the prime focus of LBT and/or of TNG optimized for deep imaging of very large fields (12'x12' on LBT and 26'x26' on TNG) through the 1 micron, J, H, K' broad-band filters. - AMICI, an ultra-high efficiency, low resolution disperser optimized for collecting complete 0.9-2.5 micron spectra of very faint objects. This device is mounted in NICS (the IR instrument for TNG) and should soon deliver spectra with quality comparable to that obtained with instruments on 8m class telescopes with similar integration times.

E. Oliva

1999-09-06

262

Continuing changes in the peculiar nebulous object PV Cephei  

NASA Technical Reports Server (NTRS)

Changes in the nebular structure, optical spectrum and stellar brightness of the faint star PV Cephei and the nebulosity associated with it are discussed. Iris photometry of the starlike object at the tip of the fan-shaped nebula reveals irregular variability of approximately 4 magnitudes in the red. Stellar spectra in the region 4300-6750 A taken from December 1976 to April 1980 are similar to the richest emission line spectra of T Tauri stars, while nebular spectra indicate a lack of spherical symmetry. Observations obtained in the infrared reveal a source offset by a few arcsec from the apex of the fan, which is identified with the illuminating star. Radial velocities of CO emission indicate that PV Cep is at the same distance as NGC 7023, and independent estimates lead to an estimated value of 500 pc. Such a distance corresponds to a bolometric luminosity approximately 100 times that of the sun. It is suggested that PV Cep is a T Tauri star that has recently broken through its circumstellar cocoon at a time when highly erratic variability and a strong stellar wind characterize the star.

Cohen, M.; Kuhi, L. V.; Spinrad, H.; Harlan, E. A.

1981-01-01

263

Probing long-period companions to planetary hosts. VLT and CFHT near infrared coronographic imaging surveys  

E-print Network

We present the results of a deep imaging survey of stars surrounded by planets detected with the radial velocity technique. The purpose is to search for and to characterize long-period stellar and substellar companions. The sample contains a total of 26 stars, among which 6 exhibit additional radial velocity drifts. We used NACO, at the ESO Very Large Telescope, and PUEO-KIR, at the Candian French Hawaiian Telescope, to conduct a near-infrared coronographic survey with adaptive optics of the faint circumstellar environment of the planetary hosts. The domain investigated ranges between 0.1 to 15" (i.e. about 3 to 500 AU, according to the mean distance of the sample). The survey is sensitive to companions within the stellar and the substellar domains, depending on the distance to the central stars and on the star properties. The images of 14 stars do not reveal any companions once the field objects are removed. 8 stars have close potential companions that need to be re-observed within 1-2 years to check for physical companionship. 4 stars are surrounded by faint objects which are confirmed or very probable companions. The companion to HD13445 (Gliese 86) is already known. The HD196885 star is a new close visual binary system with a high probability of being bound. The 2 newly discovered companions, HD1237 B and HD27442 B, share common proper motions with the central stars. Orbital motion is detected for HD1237 B. HD1237 B is likely a low-mass M star, located at 70 AU (projected distance) from the primary. HD27442 B is most probably a white dwarf companion located at about 240 AU (projected distance).

G. Chauvin; A. -M. Lagrange; S. Udry; T. Fusco; F. Galland; D. Naef; J. -L. Beuzit; M. Mayor

2006-06-07

264

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

265

Helium shells and faint emission lines from slitless flash spectra  

PubMed Central

At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen ? 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

Bazin, Cyril; Koutchmy, Serge

2013-01-01

266

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

267

Simulating a faint gamma-ray burst population  

E-print Network

There have now been three supernova-associated gamma-ray bursts (GRBs) at redshift z < 0.17, namely 980425, 030329, and 031203, but the nearby and under-luminous GRBs 980425 and 031203 are distinctly different from the `classical' or standard GRBs. It has been suggested that they could be classical GRBs observed away from their jet axes, or they might belong to a population of under-energetic GRBs. Recent radio observations of the afterglow of GRB 980425 suggest that different engines may be responsible for the observed diversity of cosmic explosions. Given this assumption, a crude constraint on a luminosity function for faint GRBs with a mean luminosity similar to that of GRB 980425 and an upper limit on the rate density of 980425-type events, we simulate the redshift distribution of under-luminous GRBs assuming BATSE and Swift sensitivities. A local rate density of about 0.6% of the local supernova Type Ib/c rate yields simulated probabilities for under-luminous events to occur at rates comparable to the BATSE GRB low-redshift distribution. In this scenario the probability of BATSE/HETE detecting at least one GRB at z<0.05 is 0.78 over 4.5 years, a result that is comparable with observation. Swift has the potential to detect 1--5 under-luminous GRBs during one year of observation.

D. M. Coward

2005-04-22

268

Luminosity Function of Faint Globular Clusters in M87  

SciTech Connect

We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our luminosity function to those that have been observed in the past, and confirm the similarity of the turnover luminosity between M87 and the Milky Way. We also find with high statistical significance that the M87 luminosity function is broader than that of the Milky Way. We discuss how determining the mass function of the cluster system to low masses can constrain theoretical models of the dynamical evolution of globular cluster systems. Our mass function is consistent with the dependence of mass loss on the initial cluster mass given by classical evaporation, and somewhat inconsistent with newer proposals that have a shallower mass dependence. In addition, the rate of mass loss is consistent with standard evaporation models, and not with the much higher rates proposed by some recent studies of very young cluster systems. We also find that the mass-size relation has very little slope, indicating that there is almost no increase in the size of a cluster with increasing mass.

Waters, Christopher Z.; Zepf, Stephen E.; /Michigan State U.; Lauer, Tod R.; /NOAO, Tucson; Baltz, Edward A.; /KIPAC, Menlo Park; Silk, Joseph; /Oxford U.

2006-07-14

269

Helium shells and faint emission lines from slitless flash spectra  

NASA Astrophysics Data System (ADS)

At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

Bazin, Cyril; Koutchmy, Serge

2013-05-01

270

Signs of a faint disc population at polluted white dwarfs  

NASA Astrophysics Data System (ADS)

Observations of atmospheric metals and dust discs around white dwarfs provide important clues to the fate of terrestrial planetary systems around intermediate-mass stars. We present Spitzer Infrared Array Camera observations of 15 metal polluted white dwarfs to investigate the occurrence and physical properties of circumstellar dust created by the disruption of planetary bodies. We find subtle infrared excess emission consistent with warm dust around KUV 15519+1730 and HS 2132+0941, and weaker excess around the DZ white dwarf G245-58, which, if real, makes it the coolest white dwarf known to exhibit a 3.6 ?m excess and the first DZ star with a bright disc. All together our data corroborate a picture where (1) discs at metal-enriched white dwarfs are commonplace and most escape detection in the infrared (possibly as narrow rings), (2) the discs are long lived, having lifetimes on the order of 106 yr or longer and (3) the frequency of bright, infrared detectable discs decreases with age, on a time-scale of roughly 500 Myr, suggesting large planetesimal disruptions decline on this same time-scale.

Bergfors, C.; Farihi, J.; Dufour, P.; Rocchetto, M.

2014-11-01

271

Deep spectroscopic luminosity function of Abell 85: no evidence for a steep upturn of the faint-end slope  

NASA Astrophysics Data System (ADS)

We present a new deep determination of the spectroscopic luminosity function (LF) within the virial radius of the nearby and massive Abell 85 (A85) cluster down to the dwarf regime (M* + 6) using Very Large Telescope/Visible Multi-Object Spectrograph (VLT/VIMOS) spectra for ˜2000 galaxies with mr ? 21 mag and ? 24 mag arcsec-2. The resulting LF from 438 cluster members is best modelled by a double Schechter function due to the presence of a statistically significant upturn at the faint end. The amplitude of this upturn (? f = -1.58^{+0.19}_{-0.15}), however, is much smaller than that of the Sloan Digital Sky Survey (SDSS) composite photometric cluster LF by Popesso et al., ?f ˜ -2. The faint-end slope of the LF in A85 is consistent, within the uncertainties, with that of the field. The red galaxy population dominates the LF at low luminosities, and is the main factor responsible for the upturn. The fact that the slopes of the spectroscopic LFs in the field and in a cluster as massive as A85 are similar suggests that the cluster environment does not play a major role in determining the abundance of low-mass galaxies.

Agulli, I.; Aguerri, J. A. L.; Sánchez-Janssen, R.; Barrena, R.; Diaferio, A.; Serra, A. L.; Méndez-Abreu, J.

2014-10-01

272

Large Scale Structures in the Universe. Cluster Analysis of Faint Galaxies in the Direction of HERCULES Void  

NASA Astrophysics Data System (ADS)

Ca. 1850 faint galaxies in the wide range of magnitudes 13m <= B <= 21m and effective surface brightness 16 ?_eff(B) <= 24 mag arcsec^-2 are detected in a field of one square degree centered at 1600+18 (1950) (Hercules void). Their coordinates (2000), magnitudes m(B), diameters, position angles surface brightness and some morphological parameters are studied using cluster analysis technique. Nearest and Furthest neighbor, Centroid, Median, Group, K means and Wards methods were used to determine the substructures in the distribution of faint galaxies. The distance metric in all the cases is squared Euclidean distance. The groups of Low surface brightness galaxies galaxies as well as the ones with high Surface Brightness were detected in such manner in the direction of the void. Edge on galaxies are not selected because of bias effects of the discrimination between stars and galaxies. Distribution of the concentration index (a parameter describing morphology of the object) was used to separate spiral and elliptical galaxies.

Petrov, G. T.; Fried, J. W.; Kniazev, A.

2006-04-01

273

The First Hyper-luminous Infrared Galaxy Discovered by WISE  

NASA Astrophysics Data System (ADS)

We report the discovery by the Wide-field Infrared Survey Explorer (WISE) of the z = 2.452 source WISE J181417.29+341224.9, the first hyperluminous source found in the WISE survey. WISE 1814+3412 is also the prototype for an all-sky sample of ~1000 extremely luminous "W1W2-dropouts" (sources faint or undetected by WISE at 3.4 and 4.6 ?m and well detected at 12 or 22 ?m). The WISE data and a 350 ?m detection give a minimum bolometric luminosity of 3.7 × 1013 L ?, with ~1014 L ? plausible. Follow-up images reveal four nearby sources: a QSO and two Lyman break galaxies (LBGs) at z = 2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission. Gravitational lensing is unlikely given the source locations and their different spectra and colors. The dominant LBG spectrum indicates a star formation rate ~300 M ? yr-1, accounting for <~ 10% of the bolometric luminosity. Strong 22 ?m emission relative to 350 ?m implies that warm dust contributes significantly to the luminosity, while cooler dust normally associated with starbursts is constrained by an upper limit at 1.1 mm. Radio emission is ~10 times above the far-infrared/radio correlation, indicating an active galactic nucleus (AGN) is present. An obscured AGN combined with starburst and evolved stellar components can account for the observations. If the black hole mass follows the local M BH-bulge mass relation, the implied Eddington ratio is >~ 4. WISE 1814+3412 may be a heavily obscured object where the peak AGN activity occurred prior to the peak era of star formation.

Eisenhardt, Peter R. M.; Wu, Jingwen; Tsai, Chao-Wei; Assef, Roberto; Benford, Dominic; Blain, Andrew; Bridge, Carrie; Condon, J. J.; Cushing, Michael C.; Cutri, Roc; Evans, Neal J., II; Gelino, Chris; Griffith, Roger L.; Grillmair, Carl J.; Jarrett, Tom; Lonsdale, Carol J.; Masci, Frank J.; Mason, Brian S.; Petty, Sara; Sayers, Jack; Stanford, S. A.; Stern, Daniel; Wright, Edward L.; Yan, Lin

2012-08-01

274

The First Hyper-Luminous Infrared Galaxy Discovered by WISE  

NASA Technical Reports Server (NTRS)

We report the discovery by the Wide-field Infrared Survey Explorer of the z = 2.452 source WISEJ181417.29+341224.9, the first hyperluminous source found in the WISE survey. WISE 1814+3412 is also the prototype for an all-sky sample of approximately 1000 extremely luminous "W1W2-dropouts" (sources faint or undetected by WISE at 3.4 and 4.6 micrometers and well detected at 12 or 22 micrometers). The WISE data and a 350 micrometers detection give a minimum bolometric luminosity of 3.7 x 10(exp 13) solar luminosity, with approximately 10(exp 14) solar luminosity plausible. Followup images reveal four nearby sources: a QSO and two Lyman Break Galaxies (LBGs) at z = 2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission. Gravitational lensing is unlikely given the source locations and their different spectra and colors. The dominant LBG spectrum indicates a star formation rate approximately 300 solar mass yr(exp -1), accounting for less than or equal to 10 percent of the bolometric luminosity. Strong 22 micrometer emission relative to 350 micrometer implies that warm dust contributes significantly to the luminosity, while cooler dust normally associated with starbursts is constrained by an upper limit at 1.1 mm. Radio emission is approximately 10? above the far-infrared/radio correlation, indicating an active galactic nucleus is present. An obscured AGN combined with starburst and evolved stellar components can account for the observations. If the black hole mass follows the local MBH-bulge mass relation, the implied Eddington ratio is approximately greater than 4. WISE 1814+3412 may be a heavily obscured object where the peak AGN activity occurred prior to the peak era of star formation.

Eisenhardt, Peter R.; Wu, Jingwen; Tsai, Chao-Wei; Assef, Roberto; Benford, Dominic; Blain, Andrew; Bridge, Carrie; Condon, J. J.; Cushing, Michael C.; Cutri, Roc; Evans, Neal J., III; Gelino, Chris; Griffith, Roger L.; Grillmair, Carl J.; Jarrett, Tom; Lonsdale, Carol J.; Masci, Frank J.; Mason, Brian S.; Petty, Sara; Sayers, Jack; Stanford, S. Adam; Stern, Daniel; Wright, Edward L.; Yan, Lin

2012-01-01

275

Realizing 3D Spectral Imaging in the Far-Infrared: FIFI LS  

E-print Network

We present a progress report on the design and construction of the Field-Imaging Far-Infrared Line Spectrometer (FIFI LS) for the SOFIA airborne observatory. The design of the instrument is driven by the goal of maximizing observing efficiency, especially for observations of faint, extragalactic objects. Thus, FIFI LS utilizes an integral field technique that uses slicer mirrors to optically re-arrange the two-dimensional field into a single slit for a long slit spectrometer. Effectively, a 5x5 pixel spatial field of view is imaged to a 25x1 pixel slit and dispersed to a 25x16 pixel, two-dimensional detector array, providing diffraction-limited spatial and spectral multiplexing. In this manner, the instrument employs two parallel, medium resolution (R~2000) grating spectrometers for simultaneous observations in two bands: a short wavelength band (42 to 110 micron) and a long wavelength band (110 to 210 micron). Overall, for each of the 25 spatial pixels, the instrument can cover a velocity range of ~1500 km/s around selected far-infrared lines with an estimated sensitivity of 2x10^-15 W Hz^1/2 per pixel. This arrangement provides good spectral coverage with high responsivity. ***This paper does not include Figures due to astro-ph size limitations. Please download entire file at http://fifi-ls.mpe-garching.mpg.de/fifils.ps.gz ****

L. W. Looney; N. Geis; R. Genzel; W. K. Park; A. Poglitsch; W. Raab; D. Rosenthal; A. Urban; T. Henning

2000-03-21

276

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

277

NASA Researches the 'FaINT' Side of Sonic Booms - Duration: 2:24.  

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,...

278

Astrometric observations of the faint outer satellites of Jupiter during the 1993 opposition  

NASA Technical Reports Server (NTRS)

Astrometric positions for the faint outer Jovian satellites VI-XIII during the 1993 opposition have been obtained from the measurement of plates taken with the 2.1 m Otto Struve reflector at McDonald Observatory.

Shelus, Peter J.; Whipple, Arthur L.; Benedict, G. F.

1993-01-01

279

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

280

The Portia group satellites as sources for faint rings  

NASA Astrophysics Data System (ADS)

The Portia group is a set of nine small satellites densely packed within 2 and 3 radii of Uranus, and some of these moons are related to faint rings: the nu ring orbits between Portia and Rosalind, while the mu ring peak is aligned with the orbit of Mab. Sfair & Giuliatti Winter (2012) showed that the alignment and the triangular radial profile of the mu ring may be explained by a combination of the dust ejection caused by the bombardment of micrometeoroids onto the surface of Mab, and the subsequent effects of the planetary oblateness and the solar radiation force acting upon the grains. In spite of all members of the Portia family are subject to a similar flux of impactors and forces, so far there is no evidence of other ring paired with a satellite. We found that a possible exception is Bianca, the innermost member of the family, and therefore less sensitive to observations. With an appropriate size for a ringThe Portia group is a set of nine small satellites densely packed within 2 and 3 radii of Uranus, and some of these moons are related to faint rings: the nu ring orbits between Portia and Rosalind, while the mu ring peak is aligned with the orbit of Mab. Sfair & Giuliatti Winter (2012) showed that the alignment and the triangular radial profile of the mu ring may be explained by a combination of the dust ejection caused by the bombardment of micrometeoroids onto the surface of Mab, and the subsequent effects of the planetary oblateness and the solar radiation force acting upon the grains. In spite of all members of the Portia family are subject to a similar flux of impactors and forces, so far there is no evidence of other ring paired with a satellite. We found that a possible exception is Bianca, the innermost member of the family, and therefore less sensitive to observations. With an appropriate size for a ring-producing moon, our calculations suggests that the bombardment may provide material to the surroundings at a rate of 40 g/s. The solar radiation force effects can be noticed in an asymmetrical triangular distribution of the ejected grains, and in the slight offset between the density peak of the resulting ring and Bianca's orbit. In our numerical simulations the dust grains can survive in the region up to 8000 years, when all dust particles are removed by collisions with the source body. This survival time allows us to estimate an upper limit of tau=10(-4) for the optical depth of this hypothetical ring, but a more accurate model is necessary to place better constrains for future observations. -producing moon, our calculations suggests that the bombardment may provide material to the surroundings at a rate of 40 g/s. The solar radiation force effects can be noticed in an asymmetrical triangular distribution of the ejected grains, and in the slight offset between the density peak of the resulting ring and Bianca's orbit. In our numerical simulations the dust grains can survive in the region up to 8000 years, when all dust particles are removed by collisions with the source body. This survival time allows us to estimate an upper limit of tau=10(-4) for the optical depth of this hypothetical ring, but a more accurate model is necessary to place better constrains for future observations.

Sfair, Rafael; Giuliatti Winter, Silvia Maria; Horn, Jason

281

Ultra-Faint Ultraviolet Galaxies at the Epoch of Peak Star Formation 1 < z < 3  

NASA Astrophysics Data System (ADS)

Ultra-faint star-forming galaxies produce a significant fraction of global star formation rate density at high redshifts. The magnification provided by strong gravitational lensing from massive clusters enables us to detect the faint background galaxies that are beyond our current detection limits. Using the massive lensing cluster Abell 1689 along with deep HST/WFC3 ultraviolet imaging (30 orbits in the F275W filter), we find that the UV luminosity function is steep down to very faint magnitudes (MUV = -13 AB mag) and shows no turnover. Our new HST program images Abell 1689 for 10 and 14 orbits in F225W and F336W bands, respectively. We again use the Lyman break technique to select star-forming galaxies as F225W and F336W “dropouts” at z=1.5 and z=2.7, respectively. Finally, we end up with a large sample of ultra-faint star-forming galaxies at the peak epoch of star formation, 1 < z < 3. We study the evolution of the faint-end slope of the UV luminosity function as well as a variety of properties of faint star-forming galaxies in this sample. We also measure the Lyman continuum escape fraction in these feeble sources, as they play an important role in making up the ionizing background radiation at both intermediate redshifts (16).

Alavi, Anahita; Siana, B. D.; Richard, J.; Stark, D.; Scarlata, C.; Teplitz, H. I.; Freeman, W. R.; Dominguez, A.; Rafelski, M.; Robertson, B. E.; Desai, V.

2014-01-01

282

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

283

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.

284

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

285

Deep galaxy count predictions in the radio, infrared, and X-ray spectral bands  

NASA Technical Reports Server (NTRS)

The existence of a dominant population of strongly evolving starburst sources at moderate redshift is a plausible explanation for the excess number of faint blue galaxies detected in deep sky surveys. Multiwavelength observations at faint magnitudes would allow the existence of such a population to be confirmed. We use observed luminosity correlations and physical properties of known starburst galaxies to predict their contribution to the deep radio, infrared, and X-ray counts, as well as to the diffuse extragalactic background radiation in these various spectral bands.

Treyer, Marie-Agnes; Silk, Joseph

1993-01-01

286

Infrared Astronomy: More Than Your Eyes Can See (Infrared View of Orion) Lithography  

NSDL National Science Digital Library

This lithograph uses images of the well-known constellation of Orion to illustrate how a common astronomical object appears in both visible light and in the infrared. The back of the lithograph tells the history of infrared light and explains the benefits of infrared astronomy.

2010-10-29

287

Infrared Astronomy and Education: Linking Infrared Whole Sky Mapping with Teacher and Student Research  

Microsoft Academic Search

The Spitzer Space Telescope and the recently launched WISE (Wide Field Infrared Survey Explorer) observe the sky in infrared light. Among the objects WISE will study are asteroids, the coolest and dimmest stars, and the most luminous galaxies. Secondary students can do authentic research using infrared data. For example, students will use WISE data to mea-sure physical properties of asteroids.

Kareen Borders; Bryan Mendez; Michelle Thaller; Varoujan Gorjian; Kyla Borders; Peter Pitman; Vincent Pereira; Babs Sepulveda; Ron Stark; Cindy Knisely; Amy Dandrea; Robert Winglee; Marge Plecki; Jeri Goebel; Matt Condit; Susan Kelly

2010-01-01

288

Near-Infrared Photon-Counting Camera for High-Sensitivity Observations  

NASA Technical Reports Server (NTRS)

The dark current of a transferred-electron photocathode with an InGaAs absorber, responsive over the 0.9-to-1.7- micron range, must be reduced to an ultralow level suitable for low signal spectral astrophysical measurements by lowering the temperature of the sensor incorporating the cathode. However, photocathode quantum efficiency (QE) is known to reduce to zero at such low temperatures. Moreover, it has not been demonstrated that the target dark current can be reached at any temperature using existing photocathodes. Changes in the transferred-electron photocathode epistructure (with an In- GaAs absorber lattice-matched to InP and exhibiting responsivity over the 0.9- to-1.7- m range) and fabrication processes were developed and implemented that resulted in a demonstrated >13x reduction in dark current at -40 C while retaining >95% of the approximately equal to 25% saturated room-temperature QE. Further testing at lower temperature is needed to confirm a >25 C predicted reduction in cooling required to achieve an ultralow dark-current target suitable for faint spectral astronomical observations that are not otherwise possible. This reduction in dark current makes it possible to increase the integration time of the imaging sensor, thus enabling a much higher near-infrared (NIR) sensitivity than is possible with current technology. As a result, extremely faint phenomena and NIR signals emitted from distant celestial objects can be now observed and imaged (such as the dynamics of redshifting galaxies, and spectral measurements on extra-solar planets in search of water and bio-markers) that were not previously possible. In addition, the enhanced NIR sensitivity also directly benefits other NIR imaging applications, including drug and bomb detection, stand-off detection of improvised explosive devices (IED's), Raman spectroscopy and microscopy for life/physical science applications, and semiconductor product defect detection.

Jurkovic, Michael

2012-01-01

289

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 ...

290

Infrared Camera  

NASA Technical Reports Server (NTRS)

A sensitive infrared camera that observes the blazing plumes from the Space Shuttle or expendable rocket lift-offs is capable of scanning for fires, monitoring the environment and providing medical imaging. The hand-held camera uses highly sensitive arrays in infrared photodetectors known as quantum well infrared photo detectors (QWIPS). QWIPS were developed by the Jet Propulsion Laboratory's Center for Space Microelectronics Technology in partnership with Amber, a Raytheon company. In October 1996, QWIP detectors pointed out hot spots of the destructive fires speeding through Malibu, California. Night vision, early warning systems, navigation, flight control systems, weather monitoring, security and surveillance are among the duties for which the camera is suited. Medical applications are also expected.

1997-01-01

291

Far Infrared Sky Survey Experiment  

Microsoft Academic Search

The present experiment extends the spectral band of the infrared sky survey to 120 microns through the use of a sounding-rocketborne superfluid-helium-cooled telescope and high-sensitivity far-infrared photoconductive detectors. The objective of the experiment is to measure the spatial and brightness distribution of the celestial background and astronomical sources in the wavelength range 8-120 microns. The experiment, which will be flown

K. Shivanandan; D. P. McNutt; S. Price; T. Murdock

1978-01-01

292

GRIS: The grating infrared spectrometer  

Microsoft Academic Search

The grating infrared spectrometer (GRIS) is an echelle grating, prism cross-dispersed, spectrometer designed for the 2.3-m Steward Observatory telescope. The cross-dispersed format utilizes a Near Infrared Camera and Multi-Object Spectrometer 3 (NICMOS 3) HgCdTe detector array for observations in the 0.86-2.5 micrometer spectral region. An echelle grating, ruled on both sides, provides resolutions of 3449 and 9439 per slit width,

Rodger I. Thompson; Harland W. Epps; Greg Winters; William Womack; Eric Mentzell

1994-01-01

293

Infrared astronomy  

NASA Technical Reports Server (NTRS)

The decade of 1990's presents an opportunity to address fundamental astrophysical issues through observations at IR wavelengths made possible by technological and scientific advances during the last decade. The major elements of recommended program are: the Space Infrared Telescope Facility (SIRTF), the Stratospheric Observatory For Infrared Astronomy (SOFIA) and the IR Optimized 8-m Telescope (IRO), a detector and instrumentation program, the SubMilliMeter Mission (SMMM), the 2 Microns All Sky Survey (2MASS), a sound infrastructure, and technology development programs. Also presented are: perspective, science opportunities, technical overview, project recommendations, future directions, and infrastructure.

Gillett, Frederick; Houck, James; Bally, John; Becklin, Eric; Brown, Robert Hamilton; Draine, Bruce; Frogel, Jay; Gatley, Ian; Gehrz, Robert; Hildebrand, Roger

1991-01-01

294

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

295

The WFC3 Infrared Spectroscopic Parallel (WISP) Survey  

NASA Astrophysics Data System (ADS)

We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of ~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 ~250 orbits. Spectra are obtained with the G 102 (? = 0.8-1.17 ?m, R ~210) and G 141 grisms (? = 1.11-1.67 ?m, R ~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 arcmin2. For typical exposure times (~6400 s in G 102 and ~2700 s in G 141), we reach 5? detection limits for emission lines of f ~ 5 × 10-17 erg s-1 cm-2 for compact objects. Typical direct imaging 5? 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? and [O III]5007,4959 Å, with H? predominating. The overall surface density of high-confidence emission-line objects in our sample is approximately 4 per arcmin2. 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?-selected sample is 4 M sun yr-1. At intermediate redshifts, we detect emission lines in galaxies as faint as H 140 ~ 25, or MR < -19, and are sensitive to SFRs down to less than 1 M sun yr-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. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 11696.

Atek, H.; Malkan, M.; McCarthy, P.; Teplitz, H. I.; Scarlata, C.; Siana, B.; Henry, A.; Colbert, J. W.; Ross, N. R.; Bridge, C.; Bunker, A. J.; Dressler, A.; Fosbury, R. A. E.; Martin, C.; Shim, H.

2010-11-01

296

Faint Population III Supernovae as the Origin of the Most Iron-poor Stars  

NASA Astrophysics Data System (ADS)

The most iron-poor stars in the Milky Way provide important observational clues to the astrophysical objects that enriched the primordial gas with heavy elements. Among them, the recently discovered iron-deficient star SMSS J031300.36-670839.3 shows a remarkable chemical composition with a non-detection of iron ([Fe/H] <-7.1) and large enhancement of carbon and magnesium relative to calcium. We investigate supernova yields of metal-free (Population III) stars to interpret the abundance pattern observed in this star. We report that the high [C/Ca] and [C/Mg] ratios and upper limits of other elemental abundances are well reproduced with the yields of core-collapse supernovae (which have normal kinetic energies of explosion E of E 51 = E/1051 erg =1) and hypernovae (E 51 >= 10) of Population III 25 M ? or 40 M ? stars. The best-fit models assume that the explosions undergo extensive matter mixing and fallback, leaving behind a black hole remnant. In these models, Ca is produced by static/explosive O burning and incomplete Si burning in the Population III supernova/hypernova, in contrast to the suggestion that Ca is originated from the hot-CNO cycle during pre-supernova evolution. Chemical abundances of four carbon-rich iron-poor stars with [Fe/H] <-4.5, including SMSS J031300.36-670839.3, are consistently explained by faint supernova models with ejected masses of 56Ni less than 10-3 M ?.

Ishigaki, Miho N.; Tominaga, Nozomu; Kobayashi, Chiaki; Nomoto, Ken'ichi

2014-09-01

297

HAWAII QUASAR AND T DWARF SURVEY. I. METHOD AND DISCOVERY OF FAINT FIELD ULTRACOOL DWARFS ,  

SciTech Connect

The Hawaii Quasar and T dwarf survey (HQT Survey) is a wide-field, red optical survey carried out with the Suprime-Cam mosaic CCD camera on the 8.2 m Subaru telescope. The HQT survey is designed to search for low-luminosity (M{sub AB1450} < -23) quasars at high redshift (z>5.7) as well as T dwarfs, both of which are selected by their very red I - z' colors. We use an optical narrowband filter NB816 to break a well-known I - z' color degeneracy between high-z quasars and foreground M and L dwarfs, which are more numerous than quasars. This paper is the first in a series of papers from the HQT survey and we report on the discovery of six faint (19 {<=} J {<=} 20) ultracool dwarfs found over a {approx}9.3 deg{sup 2} area with a limiting magnitude of z'{sub AB} {<=} 23.3. These dwarfs were confirmed by near-IR imaging and/or spectroscopy conducted at various facilities on Mauna Kea. With estimated distances of 60-170 pc, these are among the most distant spectroscopically confirmed field brown dwarfs to date. Limits on the proper motions of these ultracool dwarfs suggest that they are old members of the Galactic disk, though future follow-up observations are necessary to minimize errors. Our finding rate of ultracool dwarfs is within model predictions of Liu et al. However, the large brightening amplitude ({approx}1 mag) previously reported for the L/T transition objects appears to overpredict the numbers. We also examine how the survey field latitude affects the survey sensitivity to the vertical scale height of ultracool dwarfs.

Kakazu, Yuko; Capak, Peter L. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Hu, Esther M.; Liu, Michael C.; Wainscoat, Richard J. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Wang Weihao, E-mail: kakazu@astro.caltech.ed [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2010-11-01

298

Infrared Spectroscopy  

NSDL National Science Digital Library

This 38-page PDF document is a chapter from the Handbook of Instrumental Techniques for Analytical Chemistry. The chapter explains how infrared spectroscopy works (no comma) along with its general uses, common applications, range and limitations. Also included are spectrometer designs, information about sample preparation, analytical methods, related methods such as gas chromotography and diffuse reflectance, and costs and instrument vendors.

Hsu, C. P.; Hall, Prentice

299

Infrared astronomy  

Microsoft Academic Search

This review paper is a survey of infrared astronomy up to early 1969. The techniques and photometric standards are mentioned briefly, and results cover solar, lunar, and planetary observations. Point sources and extended sources both within and beyond the Galaxy are included, ending with the problem of cosmic background radiation. It is concluded that great progress will be possible when

Ronald F. Webbink; William Q. Jeffers

1969-01-01

300

COOL WHITE DWARFS FOUND IN THE UKIRT INFRARED DEEP SKY SURVEY  

SciTech Connect

We present the results of a search for cool white dwarfs in the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The UKIDSS LAS photometry was paired with the Sloan Digital Sky Survey to identify cool hydrogen-rich white dwarf candidates by their neutral optical colors and blue near-infrared colors, as well as faint reduced proper motion magnitudes. Optical spectroscopy was obtained at Gemini Observatory and showed the majority of the candidates to be newly identified cool degenerates, with a small number of G- to K-type (sub)dwarf contaminants. Our initial search of 280 deg{sup 2} of sky resulted in seven new white dwarfs with effective temperature T{sub eff} {approx} 6000 K. The current follow-up of 1400 deg{sup 2} of sky has produced 13 new white dwarfs. Model fits to the photometry show that seven of the newly identified white dwarfs have 4120 K {<=}T{sub eff} {<=} 4480 K, and cooling ages between 7.3 Gyr and 8.7 Gyr; they have 40 km s{sup -1} {<=} v{sub tan} {<=} 85 km s{sup -1} and are likely to be thick disk 10-11 Gyr-old objects. The other half of the sample has 4610 K {<=}T{sub eff} {<=} 5260 K, cooling ages between 4.3 Gyr and 6.9 Gyr, and 60 km s{sup -1} {<=} v{sub tan} {<=} 100 km s{sup -1}. These are either thin disk remnants with unusually high velocities, or lower-mass remnants of thick disk or halo late-F or G stars.

Leggett, S. K.; Nitta, A. [Gemini Observatory, Northern Operations Center, 670 North A'ohoku Place, Hilo, HI 96720 (United States); Lodieu, N. [Instituto de Astrofisica de Canarias (IAC), C/ Via Lactea s/n, E-38200 La Laguna, Tenerife (Spain); Tremblay, P.-E.; Bergeron, P. [Departement de Physique, Universite de Montreal, C. P. 6128, Succursale Centre-Ville, Montreal, QC H3C 3J7 (Canada)

2011-07-01

301

Symbiotic Miras vs. Planetary Nebulae in the Near Infrared  

E-print Network

While symbiotic Miras and planetary nebulae are hard to distinguish by optical spectroscopy, their near infrared colors differ. We propose the near infrared two-color diagram to be an excellent tool to easily distinguish these two classes of objects.

S. Schmeja; S. Kimeswenger

2002-08-06

302

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

303

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 along with visible light information to compile a clearer picture of the planet's weather. Clouds at different levels tell unique stories. On Earth, for example, ice crystal (cirrus) clouds are found at high altitudes while water (cumulus) clouds are at lower levels.

Besides showing details of the planet's high-altitude clouds, NICMOS also provides a clear view of the ring and the moon, Metis. Jupiter's ring plane, seen nearly edge-on, is visible as a faint line on the upper right portion of the NICMOS image. Metis can be seen in the ring plane (the bright circle on the ring's outer edge). The moon is 25 miles wide and about 80,000 miles from Jupiter.

Because of the near-infrared camera's narrow field of view, this image is a mosaic constructed from three individual images taken Sept. 17, 1997. The color intensity was adjusted to accentuate the high-altitude clouds. The dark circle on the disk of Jupiter (center of image) is an artifact of the imaging system.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1997-01-01

304

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

305

The Subaru High-z Quasar Survey: Discovery of Faint z ~ 6 Quasars  

NASA Astrophysics Data System (ADS)

We present the discovery of one or two extremely faint z ~ 6 quasars in 6.5 deg2 utilizing a unique capability of the wide-field imaging of the Subaru/Suprime-Cam. The quasar selection was made in (i'-zB ) and (zB -zR ) colors, where zB and zR are bandpasses with central wavelengths of 8842 Å and 9841 Å, respectively. The color selection can effectively isolate quasars at z ~ 6 from M/L/T dwarfs without the J-band photometry down to zR < 24.0, which is 3.5 mag deeper than the Sloan Digital Sky Survey (SDSS). We have selected 17 promising quasar candidates. The follow-up spectroscopy for seven targets identified one apparent quasar at z = 6.156 with M 1450 = –23.10. We also identified one possible quasar at z = 6.041 with a faint continuum of M 1450 = –22.58 and a narrow Ly? emission with HWHM =427 km s–1, which cannot be distinguished from Lyman ? emitters. We derive the quasar luminosity function at z ~ 6 by combining our faint quasar sample with the bright quasar samples by SDSS and CFHQS. Including our data points invokes a higher number density in the faintest bin of the quasar luminosity function than the previous estimate employed. This suggests a steeper faint-end slope than lower z, though it is yet uncertain based on a small number of spectroscopically identified faint quasars, and several quasar candidates still remain to be diagnosed. The steepening of the quasar luminosity function at the faint end does increase the expected emission rate of the ionizing photon; however, it only changes by a factor of approximately two to six. This was found to still be insufficient for the required photon budget of reionization at z ~ 6.

Kashikawa, Nobunari; Ishizaki, Yoshifumi; Willott, Chris J.; Onoue, Masafusa; Im, Myungshin; Furusawa, Hisanori; Toshikawa, Jun; Ishikawa, Shogo; Niino, Yuu; Shimasaku, Kazuhiro; Ouchi, Masami; Hibon, Pascale

2015-01-01

306

Evolution of the far-infrared luminosity functions in the Spitzer Wide-area Infrared Extragalactic Legacy Survey  

NASA Astrophysics Data System (ADS)

We present new observational determination of the evolution of the rest-frame 70 and 160 ?m and total infrared (TIR) galaxy luminosity functions (LFs) using 70 and 160 ?m data from the Spitzer Wide-area Infrared Extragalactic (SWIRE) Legacy survey. The LFs were constructed for sources with spectroscopic redshifts only in the XMM-LSS and Lockman Hole fields from the SWIRE photometric redshift catalogue. The 70 ?m and TIR LFs were constructed in the redshift range 0 < z < 1.2 and the 160 ?m LF was constructed in the redshift range 0 < z < 0.5 using a parametric Bayesian and the 1/Vmax methods. We assume in our models that the faint-end power-law index of the LF does not evolve with redshift. We find that the double power-law model is a better representation of the infrared (IR) LF than the more commonly used power-law and Gaussian model. We model the evolution of the far-IR LFs as a function of redshift where the characteristic luminosity L* evolve as ? (1+z)^{? _L}. The rest-frame 70 ?m LF shows a strong luminosity evolution out to z = 1.2 with ? _L=3.41^{+0.18}_{-0.25}. The rest-frame 160 ?m LF also showed rapid luminosity evolution with ? _L=5.53^{+0.28}_{-0.23} out to z = 0.5. The rate of evolution in luminosity is consistent with values estimated from previous studies using data from IRAS, ISO and Spitzer. The TIR LF evolves in luminosity with ? _L=3.82^{+0.28}_{-0.16} which is in agreement with previous results from Spitzer 24 ?m which find strong luminosity evolution. By integrating the LF we calculated the comoving IR luminosity density out to z = 1.2, which confirms the rapid evolution in number density of luminous IR galaxies which contribute ˜ 68+ 10- 07 per cent to the comoving star formation rate density at z = 1.2. Our results based on 70 ?m data confirm that the bulk of the star formation at z = 1 takes place in dust-obscured objects.

Patel, H.; Clements, D. L.; Vaccari, M.; Mortlock, D. J.; Rowan-Robinson, M.; Pérez-Fournon, I.; Afonso-Luis, A.

2013-01-01

307

PBS Learning Media: Infrared Gallery  

NSDL National Science Digital Library

This set of images and video produced with infrared photography lets students "see" heat radiation. Infrared is emitted by anything with a temperature -- even cold objects. The photographic technique is a way to visualize the transfer of energy from hotter to colder regions and build accurate concepts about radiant energy. Images depict a variety of objects: hot coffee, Old Faithful geyser, ice cubes, cold-blooded and warm-blooded animals, and hot springs. This resource is part of PBS Learning Media, a collection of thousands of classroom-ready, free digital resources compiled by researchers and experienced teachers to promote the use of digital learning.

2009-06-12

308

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

309

Strategies for Prompt Searches for GRB Afterglows: The Discovery of GRB 001011 Optical/Near-Infrared Counterpart Using Colour-Colour Selection  

NASA Technical Reports Server (NTRS)

We report the discovery of the optical and near-infrared counterpart to GRB 001011. The GRB 001011 error box determined by Beppo-SAX was simultaneously imaged in the near-infrared by the 3.58-m. New Technology Telescope and in the optical by the 1.54-m Danish Telescope - 8 hr after the gamma-ray event. We implement the colour-colour discrimination technique proposed by Rhoads (2001) and extend it using near-IR data as well. We present the results provided by an automatic colour-colour discrimination pipe-line developed to discern the different populations of objects present in the GRB 001011 error box. Our software revealed three candidates based on single-epoch images. Second-epoch observations carried out approx. 3.2 days after the burst revealed that the most likely candidate had faded thus identifying it with the counterpart to the GRB. In deep R-band images obtained 7 months after the burst a faint (R=25.38 plus or minus 0.25) elongated object, presumably the host galaxy of GRB 001011, was detected at the position of the afterglow. The GRB 001011 afterglow is the first discovered with the assistance of colour-colour diagram techniques. We discuss the advantages of using this method and its application to boxes determined by future missions.

Gorosabel, J.; Fynbo, J. U.; Hjorth, J.; Wolf, C.; Andersen, M. I.; Pedersen, H.; Christensen, L.; Jensen, B. L.; Moller, P.; Afonso, J.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

310

Optical and near-IR observations of the faint and fast 2008ha-like supernova 2010ae  

NASA Astrophysics Data System (ADS)

A comprehensive set of optical and near-infrared (NIR) photometry and spectroscopy is presented for the faint and fast 2008ha-like supernova (SN) 2010ae. Contingent on the adopted value of host extinction, SN 2010ae reached a peak brightness of -13.8 > MV > -15.3 mag, while modeling of the UVOIR light curve suggests it produced 0.003-0.007 M? of 56Ni, ejected 0.30-0.60 M? of material, and had an explosion energy of 0.04-0.30 × 1051 erg. The values of these explosion parameters are similar to the peculiar SN 2008ha -for which we also present previously unpublished early phase optical and NIR light curves - and places these two transients at the faint end of the 2002cx-like SN population. Detailed inspection of the post-maximum NIR spectroscopic sequence indicates the presence of a multitude of spectral features, which are identified through SYNAPPS modeling to be mainly attributed to Co ii. Comparison with a collection of published and unpublished NIR spectra of other 2002cx-like SNe, reveals that a Co ii footprint is ubiquitous to this subclass of transients, providing a link to Type Ia SNe. A visual-wavelength spectrum of SN 2010ae obtained at +252 days past maximum shows a striking resemblance to a similar epoch spectrum of SN 2002cx. However, subtle differences in the strength and ratio of calcium emission features, as well as diversity among similar epoch spectra of other 2002cx-like SNe indicates a range of physical conditions of the ejecta, highlighting the heterogeneous nature of thispeculiar class of transients. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (ESO Programs 082.A-0526, 084.D-0719, 088.D-0222, 184.D-1140, and 386.D-0966); the Gemini Observatory, Cerro Pachon, Chile (Gemini Programs GS-2010A-Q-14 and GS-2010A-Q-38); the Magellan 6.5 m telescopes at Las Campanas Observatory; and the SOAR telescope.Tables 1-5 and Appendix A are available in electronic form at http://www.aanda.orgReduced spectra are available as FITS files at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A146

Stritzinger, M. D.; Hsiao, E.; Valenti, S.; Taddia, F.; Rivera-Thorsen, T. J.; Leloudas, G.; Maeda, K.; Pastorello, A.; Phillips, M. M.; Pignata, G.; Baron, E.; Burns, C. R.; Contreras, C.; Folatelli, G.; Hamuy, M.; Höflich, P.; Morrell, N.; Prieto, J. L.; Benetti, S.; Campillay, A.; Haislip, J. B.; LaClutze, A. P.; Moore, J. P.; Reichart, D. E.

2014-01-01

311

Infrared retina  

DOEpatents

Exemplary embodiments provide an infrared (IR) retinal system and method for making and using the IR retinal system. The IR retinal system can include adaptive sensor elements, whose properties including, e.g., spectral response, signal-to-noise ratio, polarization, or amplitude can be tailored at pixel level by changing the applied bias voltage across the detector. "Color" imagery can be obtained from the IR retinal system by using a single focal plane array. The IR sensor elements can be spectrally, spatially and temporally adaptive using quantum-confined transitions in nanoscale quantum dots. The IR sensor elements can be used as building blocks of an infrared retina, similar to cones of human retina, and can be designed to work in the long-wave infrared portion of the electromagnetic spectrum ranging from about 8 .mu.m to about 12 .mu.m as well as the mid-wave portion ranging from about 3 .mu.m to about 5 .mu.m.

Krishna, Sanjay (Albuquerque, NM); Hayat, Majeed M. (Albuquerque, NM); Tyo, J. Scott (Tucson, AZ); Jang, Woo-Yong (Albuquerque, NM)

2011-12-06

312

Infrared backscattering  

NASA Technical Reports Server (NTRS)

All particles in the atmosphere are not spherical. Moreover, the scattering properties of randomly oriented nonspherical particles are not equivalent to those of spherical particles no matter how the term equivalent is defined. This is especially true for scattering in the backward direction and at the infrared wavelengths at which some atmospheric particles have strong absorption bands. Thus calculations based on Mie theory of infrared backscattering by dry or insoluble atmospheric particles are suspect. To support this assertion, it was noted that peaks in laboratory-measured infrared backscattering spectra show appreciable shifts compared with those calculated using Mie theory. One example is ammonium sulfate. Some success was had in modeling backscattering spectra of ammonium sulfate particles using a simple statistical theory called the continuous distribution of ellipsoids (CDE) theory. In this theory, the scattering properties of an ensemble are calculated. Recently a modified version of this theory was applied to measured spectra of scattering by kaolin particles. The particles were platelike, so the probability distribution of ellipsoidal shapes was chosen to reflect this. As with ammonium sulfate, the wavelength of measured peak backscattering is shifted longward of that predicted by Mie theory.

Bohren, Craig F.; Nevitt, Timothy J.; Singham, Shermila Brito

1989-01-01

313

Sub-Pixel Response Measurement of Near-Infrared Sensors  

E-print Network

Wide-field survey instruments are used to efficiently observe large regions of the sky. To achieve the necessary field of view, and to provide a higher signal-to-noise ratio for faint sources, many modern instruments are undersampled. However, precision photometry with undersampled imagers requires a detailed understanding of the sensitivity variations on a scale much smaller than a pixel. To address this, a near-infrared spot projection system has been developed to precisely characterize near-infrared focal plane arrays and to study the effect of sub-pixel non uniformity on precision photometry. Measurements of large format near-infrared detectors demonstrate the power of this system for understanding sub-pixel response.

N. Barron; M. Borysow; K. Beyerlein; M. Brown; C. Weaverdyck; W. Lorenzon; M. Schubnell; G. Tarle; A. Tomasch

2006-11-10

314

TryEngineering: Infrared Investigations  

NSDL National Science Digital Library

This is a lesson plan that explores principles of electromagnetic radiation, developed to help teachers integrate engineering practices in the secondary classroom. Students use a television remote control device to test the limitations of infrared and devise a plan for adapting infrared to work around a corner or between two rooms. The driving question of the lesson: How do engineers apply infrared technology in devices to satisfy different requirements? The lesson follows a module format that includes objectives and learner outcomes, recommended reading, illustrated procedures, and background information about the engineering connections. The TryEngineering collection is maintained by the Institute of Electrical and Electronics Engineers (IEEE). Editor's Note: We suggest supplementing this lab with interactive digital resources to help students visualize infrared radiation as part of the electromagnetic spectrum. See Related Materials for links to recommended simulations and video.

315

Retinex enhancement of infrared images.  

PubMed

With the ability of imaging the temperature distribution of body, infrared imaging is promising in diagnostication and prognostication of diseases. However the poor quality of the raw original infrared images prevented applications and one of the essential problems is the low contrast appearance of the imagined object. In this paper, the image enhancement technique based on the Retinex theory is studied, which is a process that automatically retrieve the visual realism to images. The algorithms, including Frackle-McCann algorithm, McCann99 algorithm, single-scale Retinex algorithm, multi-scale Retinex algorithm and multi-scale Retinex algorithm with color restoration, are experienced to the enhancement of infrared images. The entropy measurements along with the visual inspection were compared and results shown the algorithms based on Retinex theory have the ability in enhancing the infrared image. Out of the algorithms compared, MSRCR demonstrated the best performance. PMID:19163132

Li, Ying; He, Renjie; Xu, Guizhi; Hou, Changzhi; Sun, Yunyan; Guo, Lei; Rao, Liyun; Yan, Weili

2008-01-01

316

THE EVOLUTION OF THE REST-FRAME V-BAND LUMINOSITY FUNCTION FROM z = 4: A CONSTANT FAINT-END SLOPE OVER THE LAST 12 Gyr OF COSMIC HISTORY  

SciTech Connect

We present the rest-frame V-band luminosity function (LF) of galaxies at 0.4 {<=} z < 4.0, measured from a near-infrared selected sample constructed from the NMBS, the FIRES, the FIREWORKS, and the ultra-deep NICMOS and WFC3 observations in the HDFN, HUDF, and GOODS-CDFS, all having high-quality optical-to-mid-infrared data. This unique sample combines data from surveys with a large range of depths and areas in a self-consistent way, allowing us to (1) minimize the uncertainties due to cosmic variance; and (2) simultaneously constrain the bright and faint ends with unprecedented accuracy over the targeted redshift range, probing the LF down to 0.1L* at z {approx} 3.9. We find that (1) the faint end is fairly flat and with a constant slope from z = 4, with {alpha} = -1.27 {+-} 0.05; (2) the characteristic magnitude has dimmed by 1.3 mag from z {approx} 3.7 to z = 0.1; (3) the characteristic density has increased by a factor of {approx}8 from z {approx} 3.7 to z = 0.1, with 50% of this increase from z {approx} 4 to z {approx} 1.8; and (4) the luminosity density peaks at z Almost-Equal-To 1-1.5, increasing by a factor of {approx}4 from z = 4.0 to z Almost-Equal-To 1-1.5, and subsequently decreasing by a factor of {approx}1.5 by z = 0.1. We find no evidence for a steepening of the faint-end slope with redshift out to z = 4, in contrast with previous observational claims and theoretical predictions. The constant faint-end slope suggests that the efficiency of stellar feedback may evolve with redshift. Alternative interpretations are discussed, such as different masses of the halos hosting faint galaxies at low and high redshifts and/or environmental effects.

Marchesini, Danilo [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Stefanon, Mauro [Observatori Astronomic Universitat de Valencia, C/Catedratico Agustin Escardino Benlloch, 7, 46980, Valencia (Spain); Brammer, Gabriel B. [European Southern Observatory (ESO), Santiago (Chile); Whitaker, Katherine E. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States)

2012-04-01

317

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

318

Campaign ad war not for faint of heart -or wallet By CHARLES ELMORE  

E-print Network

, though Paul has aired program-length commercials on independent station WHDT in West Palm Beach and MiamiCampaign ad war not for faint of heart - or wallet By CHARLES ELMORE Palm Beach Post Staff Writer "shocking" the surge of hundreds of thousands of dollars of ad buys in the last six days in the West Palm

Belogay, Eugene A.

319

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

320

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

321

A VIRUS-P Survey of Galaxy Clusters to Find Faint Ly?-emitting Galaxies  

NASA Astrophysics Data System (ADS)

The VIRUS-P instrument on the 2.7m telescope at the McDonald Observatory was originally built as a prototype of the larger VIRUS instrument that will be used for HETDEX. We demonstrate that this multi-fiber, optical integral field unit spectrograph can be efficiently used to detect faint Ly?-emitting galaxies (LAEs) at intermediate redshift (z = 2-3) with the aid of gravitational lensing from galaxy clusters. The bulk z=2-3 LAEs to date have been discovered with narrowband imaging campaigns, which are highly efficient only at selecting L > L_star galaxies and only over a narrow redshift slice. By making use of gravitational lensing, however, we are able to observe intrinsically very faint galaxies that only appear to have brightnesses ? L_star. Gravitationally lensed faint LAEs, such as our sample from VIRUS-P, allow us to go fainter than existing narrowband surveys and therefore allow for better constraints at the faint end of the Ly? luminosity function at these intermediate redshifts.

McLinden, Emily; Finkelstein, S. L.; Siana, B. D.; Alavi, A.

2014-01-01

322

The Faint Young Sun Piet Martens Harvard-Smithsonian Center for  

E-print Network

(Ice age) First shelly fossils (Cambrian explosion) Snowball Earth ice ages Warm Ice age (?) #12 developed on Earth, yet geological and biological evidence points to a warm young Earth, 60 to 70 C #12;A Faint Young Sun Leaves the Earth Frozen Solid Kasting et al, Scientific American, 1988 #12;Where to look

Martens, Petrus C.

323

Compulsive Gambling "With what trembling, with what faintness of heart do I  

E-print Network

Compulsive Gambling "With what trembling, with what faintness of heart do I hear the croupier's cry for the compulsive gambler to stop. Another limiting factor that promotes self-regulation of gambling is access...With what greed do I look at the gambling table along which are strewn louis d'or, friedrichs d

Squire, Larry R.

324

Kinematic characteristics of faint meteors according to observations using an image converter  

NASA Astrophysics Data System (ADS)

A catalog of radiants, velocities, and orbital elements of faint meteors observed from 1977 to 1981 with the image-converter camera at the Physico-technical Institute of the Turkmen Academy of Sciences is presented. Of 84 meteoroid orbits listed in the catalog, 62 have been identified; 27 of them have been identified with small showers.

Mukhamednazarov, S.; Ovezgel'Dyev, O. G.; Shafiev, R. I.; Andreev, G. V.

325

Infrared spectroscopic diagnosis of thyroid tumors  

Microsoft Academic Search

The objective of this study was to assess the feasibility of infrared spectroscopy as an alternative means of screening for the diagnosis of thyroid tumors. A total of 89 fine-needle aspirates were obtained from patients with various thyroid disorders. Infrared spectra were recorded from original aspirates as well as from cell pellets obtained after centrifugation. The spectra were analyzed by

K. Z. Liu; C. P. Schultz; E. A. Salamon; A. Man; H. H. Mantsch

2003-01-01

326

Far infrared supplement: Catalog of infrared observations  

NASA Technical Reports Server (NTRS)

The Far Infrared Supplement: catalog of infrared observations summarizes all infrared astronomical observations at far infrared wavelengths published in the scientific literature between 1965 and 1982. The Supplement list contains 25% of the observations in the full catalog of infrared observations (C10), and essentially eliminates most visible stars from the listings. The Supplement is more compact than the main Catalog (it does not contain the bibliography and position index of the C10), and is intended for easy reference during astronomical observations.

Gezari, D. Y.; Schmitz, M.; Mead, J. M.

1984-01-01

327

Predicting Future Space Near-IR Grism Surveys Using the WFC3 Infrared Spectroscopic Parallels Survey  

NASA Astrophysics Data System (ADS)

We present near-infrared emission line counts and luminosity functions from the Hubble Space Telescope Wide Field Camera 3 Infrared Spectroscopic Parallels (WISP) program for 29 fields (0.037 deg2) observed using both the G102 and G141 grism. Altogether we identify 1048 emission line galaxies with observed equivalent widths greater than 40 Å, 467 of which have multiple detected emission lines. We use simulations to correct for significant (>20%) incompleteness introduced in part by the non-dithered, non-rotated nature of the grism parallels. The WISP survey is sensitive to fainter flux levels ((3-5) × 10-17 erg s-1 cm-2) than the future space near-infrared grism missions aimed at baryonic acoustic oscillation cosmology ((1-4) × 10-16 erg s-1 cm-2), allowing us to probe the fainter emission line galaxies that the shallower future surveys may miss. Cumulative number counts of 0.7 < z < 1.5 galaxies reach 10,000 deg-2 above an H? flux of 2 × 10-16 erg s-1 cm-2. H?-emitting galaxies with comparable [O III] flux are roughly five times less common than galaxies with just H? emission at those flux levels. Galaxies with low H?/[O III] ratios are very rare at the brighter fluxes that future near-infrared grism surveys will probe; our survey finds no galaxies with H?/[O III] < 0.95 that have H? flux greater than 3 × 10-16 erg s-1 cm-2. Our H? luminosity function contains a comparable number density of faint line emitters to that found by the Near IR Camera and Multi-Object Spectrometer near-infrared grism surveys, but significantly fewer (factors of 3-4 less) high-luminosity emitters. We also find that our high-redshift (z = 0.9-1.5) counts are in agreement with the high-redshift (z = 1.47) narrowband H? survey of HiZELS (Sobral et al.), while our lower redshift luminosity function (z = 0.3-0.9) falls slightly below their z = 0.84 result. The evolution in both the H? luminosity function from z = 0.3-1.5 and the [O III] luminosity function from z = 0.7-2.3 is almost entirely in the L sstarf parameter, which steadily increases with redshift over those ranges.

Colbert, James W.; Teplitz, Harry; Atek, Hakim; Bunker, Andrew; Rafelski, Marc; Ross, Nathaniel; Scarlata, Claudia; Bedregal, Alejandro G.; Dominguez, Alberto; Dressler, Alan; Henry, Alaina; Malkan, Matt; Martin, Crystal L.; Masters, Dan; McCarthy, Patrick; Siana, Brian

2013-12-01

328

Cool Cosmos: Infrared Astronomy Tutorial  

NSDL National Science Digital Library

This Web site includes the following sections: Discovery of Infrared; What is Infrared?; Infrared Astronomy; Atmospheric Windows; Near, Mid & Far Infrared; IR Astronomy Timeline; Background & Technology; The Infrared Universe; Infrared Spectroscopy; News & Discoveries; and Images & Videos.

NASA IPAC/CALTECH

329

Simulation of the infrared sky  

NASA Technical Reports Server (NTRS)

The paper describes the simulation of the infrared sky, including both astrophysical and nuisance objects, carried out in order to quantitatively study the impact of the various categories of expected events on the design of the telescope and data analysis system. Analysis of sources is outlined, and implementation of a sky model is covered.

Aumann, H. H.; Bishop, R. J.; Goldman, A. M., Jr.; Mclaughlin, W. I.

1978-01-01

330

Spectroscopy of Faint White Dwarfs - The DA/DB Ratio and the Initial-Final Mass Relation  

NASA Astrophysics Data System (ADS)

We present spectroscopic observations of very faint white dwarfs (WDs) in the rich open star cluster NGC 2099 (M37) using both GMOS on Gemini and LRIS on Keck. Of our 24 WD candidates (all fainter than V = 22.4), 21 are spectroscopically confirmed to be bona fide WDs, 4-5 of which are most likely field objects. Surprisingly, all 21 WDs are found to have hydrogen-rich atmospheres (DAs). Based on field WDs with similar temperatures, we would expect four of our objects to have helium-rich atmospheres (DB). We find this to be most likely due to the higher masses of these WDs when compared to the field sample. Hot, high mass WDs may not develop large enough helium convection zones to allow helium to be brought to the surface and turn a hydrogen-rich WD into a helium-rich one. The masses of these WDs are also used to put significant constraints on the initial-final mass relationship. We find that stars with initial masses between 2.8 and 3.4 M? lose 75% of their mass through stellar evolution.

Kalirai, J. S.; Richer, H. B.; Reitzel, D.; Hansen, B. M. S.; Rich, R. M.; Fahlman, G. G.; Gibson, B. K.; von Hippel, T.

2005-07-01

331

Cool Cosmos: Our Infrared World Gallery  

NSDL National Science Digital Library

As students tour this online gallery, they will see what familiar objects look like when viewed through an infrared camera. A scale is provided to the right of each image showing the temperature in Fahrenheit.

2009-09-01

332

Literature Objectives.  

ERIC Educational Resources Information Center

Literature experts, educators, and a national cross-section of interested laymen were gathered by the National Assessment of Educational Progress to define major objectives in literature instruction, to suggest tasks to sample these objectives and exhibit the achievements, interests, and attitudes of those exposed to literature, and to describe…

Norris, Eleanor L., Ed.; Bowes, John E., Ed.

333

Reading Objectives.  

ERIC Educational Resources Information Center

After a review of past research in reading education, Science Research Associates arrived at reading objectives which were then reviewed by the National Assessment of Educational Progress staff, educators, and laymen. The six major reading objectives, appropriate for age-groups 9, 13, 17, and young adults, are the abilities to comprehend, analyze,…

Norris, Eleanor L., Ed.; Bowes, John E., Ed.

334

Infrared source cross-index, first edition  

NASA Technical Reports Server (NTRS)

The Infrared Source Cross-Index is a listing of correlated infrared source names (and positions) for astronomical objects observed at 1-1000 microns. The source names have been obtained from the database of the first edition of the Catalog of Infrared Observations (CIO: NASA RP 1118), covering observations published through l982. Additional identifications were located by correlating these names with identifications contained in other machine-readable astronomical catalogs in the NASA National Space Science Data Center (NSSDC). There are some 80,000 different source names in the Cross-Index, corresponding to over 27,000 unique infrared sources.

Schmitz, Marion; Mead, Jaylee M.; Gezari, Daniel Y.

1987-01-01

335

High Signal-to-Noise Ratio Mid-Infrared Quasar Spectral Templates  

NASA Astrophysics Data System (ADS)

Mid-infrared (MIR) quasar spectra exhibit a suite of emission features including high ionization coronal lines from the narrow line region (NLR) illuminated by the ionizing continuum, and hot dust features from grains, as well as polycyclic aromatic hydrocarbons (PAH) features from star formation in the host galaxy. Few features are detected in most spectra because of typically low signal-to-noise ratio (S/N) data. By generating spectral composites in three different luminosity bins from over 180 Spitzer Ifnfrared Spectrograph (IRS) observations, we boost the S/N and reveal important features in the complex spectra. We detect high-ionization, forbidden emission lines in all templates, PAH features in all but the most luminous objects, and broad silicate and graphite features in emission whose strength increases relative to the continuum with luminosity. We find that the intrinsic quasar spectrum for all luminosity templates is consistent, and the differences in the spectra can be explained by host galaxy contamination in the lower luminosity templates. We also posit that star formation may be active in most quasar host galaxies, but the spectral features of star formation are only detectable if the quasar is faint.

Hill, Allison R.; Gallagher, S. C.; Deo, R. P.; Peeters, E.; Richards, Gordon T.

2014-07-01

336

Direct infrared imaging of VB 8  

NASA Astrophysics Data System (ADS)

Near-infrared images of VB 8 taken at K (2.2 microns) and L-prime (3.75 microns) during a period of good seeing at the IRTF show no evidence of the brown dwarf companion reported by McCarthy et al. (1985). Any companion 1.0 arcsec away from the primary must be at least 4 mag fainter than the primary at K and 3 mag fainter at L-prime in order to escape detection. A faint nebula centered on the star with scattering properties similar to a nebula detected near another main-sequence M star, Lalande 21185 (reported by McCarthy in 1986), may account for the extended emission detected by speckle observations.

Skrutskie, M. F.; Forrest, W. J.; Shure, M. A.

1987-01-01

337

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

338

Infrared Luminosity Functions from the Chandra Deep Field-South: The Spitzer View on the History of Dusty Star Formation at 0 <~ z <~ 1  

NASA Astrophysics Data System (ADS)

We analyze a sample of ~2600 Spitzer MIPS 24 ?m sources brighter than ~80 ?Jy and located in the Chandra Deep Field-South to characterize the evolution of the comoving infrared (IR) energy density of the universe up to z~1. Using published ancillary optical data, we first obtain a nearly complete redshift determination for the 24 ?m objects associated with R<~24 mag counterparts at z<~1. These sources represent ~55%-60% of the total MIPS 24 ?m population with f24?m>~80 ?Jy, the rest of the sample likely lying at higher redshifts. We then determine an estimate of their total IR luminosities using various libraries of IR spectral energy distributions. We find that the 24 ?m population at 0.5<~z<~1 is dominated by ``luminous infrared galaxies'' (i.e., 1011 Lsolar<=LIR<=1012 Lsolar), the counterparts of which appear to be also luminous at optical wavelengths and tend to be more massive than the majority of optically selected galaxies. A significant number of fainter sources (5×1010 Lsolar<~LIR<=1011 Lsolar) are also detected at similar distances. We finally derive 15 ?m and total IR luminosity functions (LFs) up to z~1. In agreement with the previous results from the Infrared Space Observatory (ISO) and SCUBA and as expected from the MIPS source number counts, we find very strong evolution of the contribution of the IR-selected population with look-back time. Pure evolution in density is firmly excluded by the data, but we find considerable degeneracy between strict evolution in luminosity and a combination of increases in both density and luminosity [L*IR~(1+z)3.2+0.7-0.2, ?*IR~(1+z)0.7+0.2-0.6]. A significant steepening of the faint-end slope of the IR luminosity function is also unlikely, as it would overproduce the faint 24 ?m source number counts. Our results imply that the comoving IR energy density of the universe evolves as (1+z)3.9+/-0.4 up to z~1 and that galaxies luminous in the infrared (i.e., LIR>=1011 Lsolar) are responsible for 70%+/-15% of this energy density at z~1. Taking into account the contribution of the UV luminosity evolving as (1+z)~2.5, we infer that these IR-luminous sources dominate the star-forming activity beyond z~0.7. The uncertainties affecting these conclusions are largely dominated by the errors in the k-corrections used to convert 24 ?m fluxes into luminosities. Based on observations made with Spitzer, operated by the Jet Propulsion Laboratory under NASA contract 1407.

Le Floc'h, Emeric; Papovich, Casey; Dole, Hervé; Bell, Eric F.; Lagache, Guilaine; Rieke, George H.; Egami, Eiichi; Pérez-González, Pablo G.; Alonso-Herrero, Almudena; Rieke, Marcia J.; Blaylock, Myra; Engelbracht, Charles W.; Gordon, Karl D.; Hines, Dean C.; Misselt, Karl A.; Morrison, Jane E.; Mould, Jeremy

2005-10-01

339

Far infrared supplement: Catalog of infrared observations  

NASA Technical Reports Server (NTRS)

The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

Gezari, D. Y.; Schmitz, M.; Mead, J. M.

1982-01-01

340

A classical approach to faint extragalactic source extraction from ISOCAM deep surveys. Application to the Hubble Deep Field  

NASA Astrophysics Data System (ADS)

We have developed a general data reduction technique for ISOCAM data coming from various deep surveys of faint galaxies. In order to reach the fundamental limits of the camera (due to the background photon noise and the readout noise), we have devised several steps in the reduction processes that transform the raw data to a sky map which is then used for point source and sligthly extended source extraction. The main difficulties with ISOCAM data are the long-term glitches and transient effects which can lead to false source detections or large photometric inaccuracies. In many instances, redundancy is the only way towards clear source count statistics. A sky pixel must have been ``seen'' by many different CAM pixels. Our method is based on least-squares fits to temporal data streams in order to remove the various instrumental effects. Projection onto the sky of the result of a ``triple-beam method'' (ON -(OFF1 + OFF2)/2) obtained from the signal of a given pixel during three consecutive raster positions leads to the removal of the low frequency noise. This is the classical approach when dealing with faint sources on top of a high background. We show illustrative examples of our present scheme by using data taken from the publicly available Hubble Deep Field ISOCAM survey in order to demonstrate its characteristics. More than thirty sources down to the 60 (resp. 100) mu Jy level are clearly detected above 4 sigma at wavelengths of 7 (resp. 15) mu m , the vast majority at 15 mu m . A large fraction of these sources can be identified with visible objects of median magnitude 22 and K-band magnitude of 17.5 and redshifts between 0.5 and 1 (when available). A few very red objects could be at larger redshifts. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with participation of ISAS and NASA.

Désert, F.-X.; Puget, J.-L.; Clements, D. L.; Pérault, M.; Abergel, A.; Bernard, J.-P.; Cesarsky, C. J.

1999-02-01

341

ORIGINAL PAPER Optimization of the Near-Infrared Fluorescence Labeling  

E-print Network

ORIGINAL PAPER Optimization of the Near-Infrared Fluorescence Labeling for In Vivo Monitoring The objective of this study is to optimize the parameters in labeling near-infrared (NIR)fluorescent dye cypate Near infrared . Fluorescence dye . Protein drugs . Labeling condition . In vivo optical imaging

Larson-Prior, Linda

342

New `Moons' of Saturn May Be Transient Objects  

NASA Astrophysics Data System (ADS)

ADONIS Observes Pandora, S/1995 S6 and Others How many moons has Saturn, the second-largest planet in the solar system ? Until recently, the best answer was eighteen, ranging from innermost Pan that circles the planet 75,000 km above the cloud tops in a little less than 14 hours, to distant Phoebe , 13 million km away in a reverse (`retrograde') 550-day orbit [1]. Now the situation is less clear. New observations have become available which raise some questions about the actual number and nature of small `moons' near this planet. In particular, there is now evidence that some of the recent sightings may in fact refer to temporary condensations of material (dust clouds) in the inner rings rather than solid bodies. Most of these observations have been made with the Hubble Space Telescope (HST), but important supplementary data [2] was also obtained with the high-resolution ADONIS camera at the ESO 3.6-m telescope. When the Sun and Earth Cross the Plane of the Rings Saturn is surrounded by a spectacular ring system in which a large number of small (probably cm- to m-size) icy bodies are moving. Soon after the invention of the telescope in the early 17th century, it was found to consist of an inner B- and an outer A-ring, separated by the dark `Cassini division'. The faint F-ring was discovered further out by the Pioneer 11 spacecraft in 1979; it is separated from the A-ring by the 3000-km wide `Pioneer division'. All of these rings are very flat and quite thin. They are apparently no more than 2 kilometres thick in a global sense, and probably much less locally (10 - 100 metres). They all lie in the same plane which is inclined by 26.7 degrees, relative to the planet's orbital plane. One revolution of Saturn around the Sun lasts 29.455 years and twice during each orbital period, i.e. once about every 15 years, the Sun is situated exactly in this ring plane. This happened most recently on November 19, 1995. Astronomers refer to these relatively rare events as solar ring plane crossings (RPX) . At the corresponding times, the Sun illuminates the thin Saturnian rings exactly from the side. Due to its own orbital motion around the Sun, the Earth will cross the ring plane either once or three times, just before and/or after a solar RPX event. In 1995, this happened on May 22 and August 10, and there will be a third Earth RPX event on February 11, 1996. RPX Events Offer Improved Possibilities to Discover Faint Moons The apparent brightness of Saturn's rings decreases dramatically around the time of a solar RPX event. It is then much easier to detect faint moons which would otherwise be lost in the strong glare of Saturn's ring system. Also, the edge-on view improves the chances of detecting faint and dilute rings [3]. Moreover, numerous `mutual events' (eclipses and occultations) occur between the moons during this period; exact timing of these events allows highly improved determination of the motions and orbits around Saturn of these objects. The most recent Earth RPX event took place on August 10, 1995. At this time, Saturn was situated nearly opposite the Sun (in `opposition'), as seen from the Earth, and conditions were very favourable for astronomical observations from both hemispheres. However, because of the longer nights during the southern winter, observing possibilities were particularly good in the south and thus at the ESO La Silla Observatory. The ADONIS Observations Here, a team of astronomers (Jean-Luc Beuzit, Bruno Sicardy and Francois Poulet of the Paris Observatory; Pablo Prado from ESO) followed this rare event during 6 half-nights around August 10, 1995, with the advanced ADONIS adaptive optics camera at the ESO 3.6-m telescope. This instrument neutralizes the image-smearing effects of the atmospheric turbulence and records very sharp images on an infrared-sensitive 256 x 256 pixel detector with a scale of 0.05 arcsec/pixel. Most of the Saturn images were taken through the `short K' filter with a central wavelength at 2.2 micron. This near-infrared wavelength region is characterised by strong absorption lines

1996-01-01

343

Spectroscopic Infrared Ellipsometry  

E-print Network

Spectroscopic Infrared Ellipsometry: Components, Calibration, and Application #12;CIP-DATA KONINKLIJKE BIBLIOTHEEK, DEN HAAG Boer, Johannes Henricus Wilhelmus Gerardus den Spectroscopic Infrared in Dutch. ISBN 90 386 0017 8 Subject headings: spectroscopy ellipsometry infrared. #12;Spectroscopic

Eindhoven, Technische Universiteit

344

Vague objects  

E-print Network

Peter Unger's puzzle, the problem of the many, is an argument for the conclusion that we are grossly mistaken about what kinds of objects are in our immediate surroundings. But it is not clear what we should make of Unger's ...

Ólafur Páll Jónsson

2001-01-01

345

At near-infrared wavelengths, following the subtraction of zodiacal light  

NASA Technical Reports Server (NTRS)

At near-infrared wavelengths, following the subtraction of zodiacal light (see Slide 16), map pixels containing discrete bright sources are masked and the DIRBE Faint Source Model is used to subtract residual Galactic starlight in order to detect or place an upper limit on the brightness of the cosmic infrared (extragalactic) background emission (Arendt et al. 1998, ApJ, in press). Here the upper map shows the residual sky brightness at 2.2 Aum after zodiacal light subtraction and bright source masking (dark spots in maps). In this projection, the Galactic plane runs horizontally through the map. Ideally, if the zodiacal model were perfect, only the collective emissions of (faint) stars in the Milky Way and the sought-after extragalactic light (cosmic infrared background) would remain in this map. The lower map shows the DIRBE Faint Source Model. To facilitate comparison, both maps are shown on the same brightness scale and with the same pixels masked. Clearly, most of the residual 2.2 Aum emission in the upper map is attributable to stars in the Milky Way.

2002-01-01

346

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

347

THE LAS CAMPANAS INFRARED SURVEY. III. THE H-BAND IMAGING SURVEY AND THE NEAR-INFRARED AND OPTICAL PHOTOMETRIC CATALOGS  

E-print Network

THE LAS CAMPANAS INFRARED SURVEY. III. THE H-BAND IMAGING SURVEY AND THE NEAR-INFRARED AND OPTICAL on broadband optical and near-infrared photometry, is designed to robustly identify a statistically significant-reduction techniques, and object identification procedures. We present sam- ple near-infrared and optical photometric

Goddard III, William A.

348

Feasibility of symmetry-based speckle noise reduction for faint companion detection.  

PubMed

Great interest has been focused on the problem of detecting faint companions, possibly including extrasolar planets, very close to other stars. A promising approach involves coupling high-correction adaptive optics to coronagraphs, for which many new and innovative designs have emerged. Detection of faint companions will require suppression of noise due to fluctuating speckles from the remnant fraction of stellar light not adaptively controlled. At high correction, the speckle halo takes on distinct spatial symmetries that may allow partial speckle noise reduction through relatively simple post-processing that rejects one spatial symmetry in the image. This paper quantitatively examines potential companion-detection sensitivity improvements that might be expected, and shows that realistic operational parameters will allow them to be realized. PMID:19532716

Bloemhof, E E

2007-04-16

349

Archean Earth Atmosphere Fractal Haze Aggregates: Light Scattering Calculations and the Faint Young Sun Paradox  

Microsoft Academic Search

As part of an ongoing undergraduate research project of light scattering calculations involving fractal carbonaceous soot aggregates relevant to current anthropogenic and natural sources in Earth's atmosphere, we have read with interest a recent paper [E.T. Wolf and O.B Toon,Science 328, 1266 (2010)] claiming that the Faint Young Sun paradox discussed four decades ago by Carl Sagan and others can

D. A. Boness; B. Terrell-Martinez

2010-01-01

350

Neutral hydrogen detection survey of dwarf galaxies. II. Faint Virgo dwarfs and a field sample  

SciTech Connect

Neutral hydrogen spectra are presented for 53 faint dwarf galaxies in Virgo, completing the Arecibo survey of all late-type dwarfs in the Virgo Cluster Catalog, and for 42 dwarf galaxies from the field sample of Binggeli et al. (1989). For detected galaxies, heliocentric velocities, profile widths, and single-beam fluxes are tabulated. The field sample has been used to investigate the field luminosity function and the clustering of dwarf galaxies vis-a-vis bright galaxies. 31 refs.

Hoffman, G.L.; Williams, H.L.; Salpeter, E.E.; Sandage, A.; Binggeli, B. (Lafayette College, Easton, PA (USA) Delaware Univ., Newark (USA) Cornell Univ., Ithaca, NY (USA) Mount Wilson and Las Campanas Observatories, Pasadena, CA (USA) Arcetri, Osservatorio Astrofisico, Florence (Italy))

1989-12-01

351

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

352

Mid-Infrared and Near-Infrared Spectroscopic Properties of Fusarium Isolates: Effects of Culture Conditions  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Fusarium genus includes soil saprobes as well as pathogenic or toxin-producing species. Traditional classification of Fusarium isolates is slow and requires a high level of expertise. The objective of this project is to describe culture condition effects on mid-infrared (MidIR) and near-infrared...

353

FAINT COLLIMATED HERBIG-HARO JETS FROM VISIBLE STARS IN L1641  

SciTech Connect

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{alpha} 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{alpha} emission stars within the region surveyed, 8% are found to be associated with jets.

Reipurth, Bo; Aspin, Colin; Walawender, Josh [Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, HI 96720 (United States); Bally, John [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Tobin, John J., E-mail: reipurth@ifa.hawaii.ed, E-mail: caa@ifa.hawaii.ed, E-mail: joshw@ifa.hawaii.ed, E-mail: John.Bally@colorado.ed, E-mail: jjtobin@umich.ed [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)

2010-09-15

354

Discovery of a New Faint Dwarf Galaxy Associated with NGC 253  

NASA Astrophysics Data System (ADS)

We report the discovery of a new faint dwarf galaxy, which we dub Scl-MM-Dw1, at a projected distance of ~65 kpc from the spiral galaxy NGC 253. The discovery results from the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), a program with the Magellan/Megacam imager to study faint substructure in resolved stellar light around massive galaxies outside of the Local Group. We measure a tip of the red giant branch distance to Scl-MM-Dw1 of D = 3.9 ± 0.5 Mpc, consistent with that of NGC 253, making their association likely. The new dwarf's stellar population is complex, with an old, metal-poor red giant branch (gsim10 Gyr, [Fe/H] ~ -2), and an asymptotic giant branch with an age of ~500 Myr. Scl-MM-Dw1 has a half-light radius of rh = 340 ± 50 pc and an absolute magnitude of MV = -10.3 ± 0.6 mag, comparable to the Milky Way's satellites at the same luminosity. Once complete, our imaging survey of NGC 253 and other nearby massive galaxies will provide a census of faint substructure in halos beyond the Local Group, both to put our own environment into context and to confront models of hierarchical structure formation. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Sand, D. J.; Crnojevi?, D.; Strader, J.; Toloba, E.; Simon, J. D.; Caldwell, N.; Guhathakurta, P.; McLeod, B.; Seth, A. C.

2014-09-01

355

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

356

On the origin of the faint-end of the red sequence in high-density environments  

NASA Astrophysics Data System (ADS)

With the advent of the new generation wide-field cameras it became possible to survey in an unbiased mode galaxies spanning a variety of local densities, from the core of rich clusters, to compact and loose groups, down to filaments and voids. The sensitivity reached by these instruments allowed to extend the observation to dwarf galaxies, the most "fragile" objects in the universe. At the same time models and simulations have been tailored to quantify the different effects of the environment on the evolution of galaxies. Simulations, models, and observations consistently indicate that star-forming dwarf galaxies entering high-density environments for the first time can be rapidly stripped from their interstellar medium. The lack of gas quenches the activity of star formation, producing on timescales of 1 Gyr quiescent galaxies with spectro-photometric, chemical, structural, and kinematical properties similar to those observed in dwarf early-type galaxies inhabiting rich clusters and loose groups. Simulations and observations consistently identify ram pressure stripping as the major effect responsible for the quenching of the star-formation activity in rich clusters. Gravitational interactions (galaxy harassment) can also be important in groups or in clusters whenever galaxies have been members since early epochs. The observation of clusters at different redshifts combined with the present high infalling rate of galaxies onto clusters indicate that the quenching of the star-formation activity in dwarf systems and the formation of the faint end of the red sequence is a very recent phenomenon.

Boselli, Alessandro; Gavazzi, Giuseppe

2014-11-01

357

NGC 300: AN EXTREMELY FAINT, OUTER STELLAR DISK OBSERVED TO 10 SCALE LENGTHS J. Bland-Hawthorn  

E-print Network

NGC 300: AN EXTREMELY FAINT, OUTER STELLAR DISK OBSERVED TO 10 SCALE LENGTHS J. Bland-Hawthorn of the formation process (Freeman & Bland-Hawthorn 2002; van der Kruit 1987; Ferguson & Clarke 2001). By mea

Draine, Bruce T.

358

Faint Debris Detection by Particle Based Track-Before-Detect Method  

NASA Astrophysics Data System (ADS)

This study proposes a particle method to detect faint debris, which is hardly seen in single frame, from an image sequence based on the concept of track-before-detect (TBD). The most widely used detection method is detect-before-track (DBT), which firstly detects signals of targets from single frame by distinguishing difference of intensity between foreground and background then associate the signals for each target between frames. DBT is capable of tracking bright targets but limited. DBT is necessary to consider presence of false signals and is difficult to recover from false association. On the other hand, TBD methods try to track targets without explicitly detecting the signals followed by evaluation of goodness of each track and obtaining detection results. TBD has an advantage over DBT in detecting weak signals around background level in single frame. However, conventional TBD methods for debris detection apply brute-force search over candidate tracks then manually select true one from the candidates. To reduce those significant drawbacks of brute-force search and not-fully automated process, this study proposes a faint debris detection algorithm by a particle based TBD method consisting of sequential update of target state and heuristic search of initial state. The state consists of position, velocity direction and magnitude, and size of debris over the image at a single frame. The sequential update process is implemented by a particle filter (PF). PF is an optimal filtering technique that requires initial distribution of target state as a prior knowledge. An evolutional algorithm (EA) is utilized to search the initial distribution. The EA iteratively applies propagation and likelihood evaluation of particles for the same image sequences and resulting set of particles is used as an initial distribution of PF. This paper describes the algorithm of the proposed faint debris detection method. The algorithm demonstrates performance on image sequences acquired during observation campaigns dedicated to GEO breakup fragments, which would contain a sufficient number of faint debris images. The results indicate the proposed method is capable of tracking faint debris with moderate computational costs at operational level.

Uetsuhara, M.; Ikoma, N.

2014-09-01

359

Solutions to the faint young Sun paradox simulated by a general circulation model  

NASA Astrophysics Data System (ADS)

The faint young Sun paradox has dominated our thinking regarding early climate. Geological evidence abounds for warm, possibly hot, seawater temperatures and the proliferation of early life during the Archean period of Earth's history (3.8-2.5 Ga). However the standard solar model indicates that the Sun was only 75 to 82 percent as bright as today, implying an apparent contradiction between warm surface temperatures and weak solar irradiance. Geological evidence also places constraints on the amount of atmospheric carbon dioxide present early in Earth's history. Over the past four decades there has been much debate amongst geological, planetary, and climate science communities regarding how to properly resolve the issue of the faint young Sun. Up until very recently, 1-dimensional radiative convective models were the standard tool for deep paleoclimate modeling studies. These studies have notably lacked the ability to treat clouds, surface ice, and meridional energy transport. However, advancements in computing technology now allow us to tackle the faint young Sun paradox using a three-dimensional climate model. 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. Modest amounts of carbon dioxide and methane can provide adequate warming for the Archean within given constraints. Cooler climates with large ice caps but temperate tropical regions can be supported with even less carbon dioxide. The incorporation of systematic climate system differences expected during the Archean, such as fewer cloud condensation nuclei, reduced land albedos, and increased atmospheric nitrogen, can provide additional non-greenhouse means of warming the early Earth. A warm Archean no longer appears at odds with a faint young Sun. Here, we will also discuss the consequences of the oft-suggested Titan-like photochemical haze that may have enshrouded the early Earth if methane was a significant constituent of the atmosphere. Finally, we briefly consider the inverse problem. What fate may be in store for the Earth as the Sun continues to brighten far past its present level?

Wolf, Eric Theodore

360

Performance of the HgCdTe detector for MOSFIRE, an imager and multi-object spectrometer for Keck Observatory  

NASA Astrophysics Data System (ADS)

MOSFIRE is a new multi-object near-infrared spectrometer for the Keck 1 telescope with a spectral resolving power of R~3500 for a 0.7'' slit (2.9 pixels). The detector is a substrate-removed 2K × 2K HAWAII 2-RG HgCdTe array from Teledyne Imaging Sensors with a cut-off wavelength of 2.5 ?m and an operational temperature of 77K. Spectroscopy of faint objects sets the requirement for low dark current and low noise. MOSFIRE is also an infrared camera with a 6.9' field of view projected onto the detector with 0.18'' pixel sampling. Broad-band imaging drives the requirement for 32-channel readout and MOSFIREs fast camera optics implies the need for a very at detector. In this paper we report the final performance of the detector selected for MOSFIRE. The array is operated using the SIDECAR ASIC chip inside the MOSFIRE dewar and v2.3 of the HxRG software. Dark current plus instrument background is measured at <0.008 ° s-1 pixel-1 on average. Multiple Correlated Double Sampling (MCDS) and Up-The-Ramp (UTR) sampling are both available. A read noise of <5° rms is achieved with MCDS 16 and the lowest noise of 3° rms occurs for 64 samples. Charge persistence depends on exposure level and shows a large gradient across this detector. However, the decay time constant is always ~660 seconds. Linearity and stability are also discussed.

Kulas, Kristin R.; McLean, Ian S.; Steidel, Charles C.

2012-07-01

361

THE FAINT END OF THE GALAXY LUMINOSITY FUNCTION IN A1689: A STEEP RED FAINT END UPTURN AT z = 0.18  

SciTech Connect

We present a deep and wide I luminosity function (LF) for galaxies in A1689 (z = 0.183) from a mosaic of Hubble Space Telescope WFPC2 images covering 10' on the side. The main result of this work is the detection of a steep upturn in the dwarf galaxy LF, with {alpha} {approx} -2. The dwarf-to-giant ratio appears to increase outward, but this is because giant galaxies are missing in the cluster outskirts, indicating luminosity segregation. The red sequence LF has the same parameters, within errors, as the total LF, showing that the faint end upturn consists of red quiescent galaxies. We speculate that the upturn is connected to the 'filling-in' of the red sequence at z < 0.4 and may represent the latest installment of 'downsizing' as the least massive galaxies are being quenched at the present epoch.

Banados, Eduardo [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Hung Liwei [Department of Astronomy, Ohio State University, Columbus, OH (United States); De Propris, Roberto [Cerro Tololo Inter-American Observatory, La Serena (Chile); West, Michael J. [European Southern Observatory, Santiago (Chile)

2010-09-20

362

AGN Search From Multicolor CCD Photometric Observations of Faint ROSAT X-ray Sources in a One Square Degree Field  

NASA Astrophysics Data System (ADS)

We present the optical identifications of 75 X-ray sources in a 1 sq. deg. overlapping region, T329 of BATC sky survey with a medium deep ROSAT survey (Molthagen et al. 1997), based on multi-color CCD imaging observations made for the T329 utilizing BAO 60/90 cm Schmidt telescope with 15 intermediate-band filters covering the wavelength range 3360-9745 AA. These X-ray sources are relatively faint (CR << 0.2 s-1) and thus mostly are not included in the RBS catalogue and also remained as unidentified sources in a previous identification program carried out by the Hamburg Quasar Survey. Within their position-error circles, All of the X-ray sources were observed to have one or more spatially associated optical counterparts down to the magnitude mv=21.5. The majority of these optical objects could be classified according to their SED information constructed from the 15 color photometric catalogue of T329. This finally leads to 43 (~57%) of 75 X-ray sources are identified with AGNs, 19 (~25%) and 8 (~11%) are identified with various types of galaxies and late stars respectively. About one third sources in the AGN list (including 4 known AGNs) have follow up spectroscopic observations, confirming their QSO/Seyfert or NELG nature. Further more spectroscopic observations are partially ongoing with the Multiple Object Fiber Spectrograph (MOFS) of SAO 6m telescope, which will help to form a complete, X-ray flux limited AGN sample in a 1 square degree field.

Xue, Suijian; Zhou, Xu; Zhang, H.

363

Infrared Luminosity Function of the Coma Cluster  

E-print Network

Using mid-IR and optical data, we deduce the total infrared (IR) luminosities of galaxies in the Coma cluster and present their infrared luminosity function (LF). The shape of the overall Coma IR LF does not show significant differences from the IR LFs of the general field, which indicates the general independence of global galaxy star formation on environment up to densities $\\sim$ 40 times greater than in the field (we cannot test such independence above $L_{ir} \\approx 10^{44} {\\rm ergs s}^{-1}$). However, a shallower faint end slope and a smaller $L_{ir}^{*}$ are found in the core region (where the densities are still higher) compared to the outskirt region of the cluster, and most of the brightest IR galaxies are found outside of the core region. The IR LF in the NGC 4839 group region does not show any unique characteristics. By integrating the IR LF, we find a total star formation rate in the cluster of about 97.0 $M_{\\sun}{\\rm yr}^{-1}$. We also studied the contributions of early- and late-type galaxies to the IR LF. The late-type galaxies dominate the bright end of the LF, and the early-type galaxies, although only making up a small portion ($\\approx$ 15%) of the total IR emission of the cluster, contribute greatly to the number counts of the LF at $L_{ir} < 10^{43} {\\rm ergs s}^{-1}$.

Lei Bai; George H. Rieke; Marcia J. Rieke; Joannah L. Hinz; Douglas M. Kelly; Myra Blaylock

2005-12-02

364

THE TAIWAN ECDFS NEAR-INFRARED SURVEY: ULTRA-DEEP J AND K{sub S} IMAGING IN THE EXTENDED CHANDRA DEEP FIELD-SOUTH  

SciTech Connect

We present ultra-deep J and K{sub S} imaging observations covering a 30' Multiplication-Sign 30' area of the Extended Chandra Deep Field-South (ECDFS) carried out by our Taiwan ECDFS Near-Infrared Survey (TENIS). The median 5{sigma} limiting magnitudes for all detected objects in the ECDFS reach 24.5 and 23.9 mag (AB) for J and K{sub S} , respectively. In the inner 400 arcmin{sup 2} region where the sensitivity is more uniform, objects as faint as 25.6 and 25.0 mag are detected at 5{sigma}. Thus, this is by far the deepest J and K{sub S} data sets available for the ECDFS. To combine TENIS with the Spitzer IRAC data for obtaining better spectral energy distributions of high-redshift objects, we developed a novel deconvolution technique (IRACLEAN) to accurately estimate the IRAC fluxes. IRACLEAN can minimize the effect of blending in the IRAC images caused by the large point-spread functions and reduce the confusion noise. We applied IRACLEAN to the images from the Spitzer IRAC/MUSYC Public Legacy in the ECDFS survey (SIMPLE) and generated a J+K{sub S} -selected multi-wavelength catalog including the photometry of both the TENIS near-infrared and the SIMPLE IRAC data. We publicly release the data products derived from this work, including the J and K{sub S} images and the J+K{sub S} -selected multi-wavelength catalog.

Hsieh, Bau-Ching; Wang, Wei-Hao; Hsieh, Chih-Chiang; Lin, Lihwai; Lim, Jeremy; Ho, Paul T. P. [Institute of Astrophysics and Astronomy, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Yan Haojing [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States)

2012-12-15

365

Faint Submillimeter Galaxies Revealed by Multifield Deep ALMA Observations: Number Counts, Spatial Clustering, and a Dark Submillimeter Line Emitter  

NASA Astrophysics Data System (ADS)

We present the statistics of faint submillimeter/millimeter galaxies (SMGs) and serendipitous detections of a submillimeter/millimeter line emitter (SLE) with no multi-wavelength continuum counterpart revealed by the deep ALMA observations. We identify faint SMGs with flux densities of 0.1-1.0 mJy in the deep Band-6 and Band-7 maps of 10 independent fields that reduce cosmic variance effects. The differential number counts at 1.2 mm are found to increase with decreasing flux density down to 0.1 mJy. Our number counts indicate that the faint (0.1-1.0 mJy, or SFRIR ~ 30-300 M ? yr–1) SMGs contribute nearly a half of the extragalactic background light (EBL), while the remaining half of the EBL is mostly contributed by very faint sources with flux densities of <0.1 mJy (SFRIR <~ 30 M ? yr–1). We conduct counts-in-cells analysis with multifield ALMA data for the faint SMGs, and obtain a coarse estimate of galaxy bias, b g < 4. The galaxy bias suggests that the dark halo masses of the faint SMGs are <~ 7 × 1012 M ?, which is smaller than those of bright (>1 mJy) SMGs, but consistent with abundant high-z star-forming populations, such as sBzKs, LBGs, and LAEs. Finally, we report the serendipitous detection of SLE-1, which has no continuum counterparts in our 1.2 mm-band or multi-wavelength images, including ultra deep HST/WFC3 and Spitzer data. The SLE has a significant line at 249.9 GHz with a signal-to-noise ratio of 7.1. If the SLE is not a spurious source made by the unknown systematic noise of ALMA, the strong upper limits of our multi-wavelength data suggest that the SLE would be a faint galaxy at z >~ 6.

Ono, Yoshiaki; Ouchi, Masami; Kurono, Yasutaka; Momose, Rieko

2014-11-01

366

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

367

THE FAINT END OF THE CLUSTER-GALAXY LUMINOSITY FUNCTION AT HIGH REDSHIFT  

SciTech Connect

We measure the faint-end slope of the galaxy luminosity function (LF) for cluster galaxies at 1 < z < 1.5 using Spitzer IRAC data. We investigate whether this slope, {alpha}, differs from that of the field LF at these redshifts, and with the cluster LF at low redshifts. The latter is of particular interest as low-luminosity galaxies are expected to undergo significant evolution. We use seven high-redshift spectroscopically confirmed galaxy clusters drawn from the IRAC Shallow Cluster Survey to measure the cluster-galaxy LF down to depths of M* + 3 (3.6 {mu}m) and M* + 2.5 (4.5 {mu}m). The summed LF at our median cluster redshift (z = 1.35) is well fit by a Schechter distribution with {alpha}{sub 3.6{mu}m} = -0.97 {+-} 0.14 and {alpha}{sub 4.5{mu}m} = -0.91 {+-} 0.28, consistent with a flat faint-end slope and is in agreement with measurements of the field LF in similar bands at these redshifts. A comparison to {alpha} in low-redshift clusters finds no statistically significant evidence of evolution. Combined with past studies which show that M* is passively evolving out to z {approx} 1.3, this means that the shape of the cluster LF is largely in place by z {approx} 1.3. This suggests that the processes that govern the buildup of the mass of low-mass cluster galaxies have no net effect on the faint-end slope of the cluster LF at z {approx}< 1.3.

Mancone, Conor L.; Baker, Troy; Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Ashby, Matthew L. N.; Snyder, Greg [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stanford, Spencer A. [Physics Department, University of California, Davis, CA 95616 (United States); Brodwin, Mark [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Eisenhardt, Peter R. M.; Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Wright, Edward L., E-mail: cmancone@astro.ufl.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States)

2012-12-20

368

The Faint End of the Cluster-galaxy Luminosity Function at High Redshift  

NASA Astrophysics Data System (ADS)

We measure the faint-end slope of the galaxy luminosity function (LF) for cluster galaxies at 1 < z < 1.5 using Spitzer IRAC data. We investigate whether this slope, ?, differs from that of the field LF at these redshifts, and with the cluster LF at low redshifts. The latter is of particular interest as low-luminosity galaxies are expected to undergo significant evolution. We use seven high-redshift spectroscopically confirmed galaxy clusters drawn from the IRAC Shallow Cluster Survey to measure the cluster-galaxy LF down to depths of M* + 3 (3.6 ?m) and M* + 2.5 (4.5 ?m). The summed LF at our median cluster redshift (z = 1.35) is well fit by a Schechter distribution with ?3.6 ?m = -0.97 ± 0.14 and ?4.5 ?m = -0.91 ± 0.28, consistent with a flat faint-end slope and is in agreement with measurements of the field LF in similar bands at these redshifts. A comparison to ? in low-redshift clusters finds no statistically significant evidence of evolution. Combined with past studies which show that M* is passively evolving out to z ~ 1.3, this means that the shape of the cluster LF is largely in place by z ~ 1.3. This suggests that the processes that govern the buildup of the mass of low-mass cluster galaxies have no net effect on the faint-end slope of the cluster LF at z <~ 1.3.

Mancone, Conor L.; Baker, Troy; Gonzalez, Anthony H.; Ashby, Matthew L. N.; Stanford, Spencer A.; Brodwin, Mark; Eisenhardt, Peter R. M.; Snyder, Greg; Stern, Daniel; Wright, Edward L.

2012-12-01

369

Detection of the Angular Correlation of Faint X-ray Sources  

E-print Network

We have analyzed a set of deep ROSAT observations with a total sky coverage of 40 square degrees to search for clustering of faint X-ray sources. Using the resulting catalog of discrete X-ray sources, we detect, for the first time in X-rays, a positive correlation on angular scales of 0.5'-10'. When corrected for a bias due to limited spatial resolution which amplifies the correlation, the observed angular correlation function agrees well with that expected from the spatial correlation of optically selected quasars, provided that they comprise an appreciable fraction (>= ~50%) of detected X-ray sources.

A. Vikhlinin; W. Forman

1995-10-06

370

An optical study of the faint end of the stellar luminosity function  

NASA Technical Reports Server (NTRS)

We implement a new method by which to study the faint end of the field star luminosity function. The method relies on deep, multicolor photometry of fields projected against highly obscured, nearby molecular clouds. The clouds act as nearby opaque screens and delimit a well-defined survey volume which is in principle free of the problem of distinguishing nearby, intrinsically faint dwarf stars from more distant red giants. This study is based upon deep photographic and CCD photometry at optical (V, R, I) bandpasses toward the most highly obscured portions of the Taurus and Ophiuchus molecular clouds. The total volume delimited by the clouds is approximately 200 cu pc. Within this region our survey is complete for all stars brighter than M(sub V) = 16-17 mag; at R and I, the survey is complete down to the lowest mass stars capable of sustaining core hydrogen burning. We estimate the faint end of the field star luminosity function for the composite Taurus and Ophiuchus foreground sample and find that it resembles the local luminosity function down to M(sub V) approx. 16. At still fainter magnitudes we find more stars than do photometric parallex studies of the polar regions. This difference widens dramatically if even the simplest correction for incompleteness is applied to our data. We therefore tentatively conclude that the luminosity function rises beyond M(sub V) approx. 16; even if we discard our attempts to correct for incompleteness in the faintest magnitude bins, the luminosity function at least remains flat for the lowest mass stars. Our provisional finding that the luminosity function rises beyond its well-known peak at M(sub V) approx. 12-13, implies that the initial mass function (IMF) probably rises beyond the turnover point associated with this peak. Even if our most conservative estimate for the faint end of the luminosity function is used-in which no corrections are made for incompleteness-the IMF must at least remain flat down to the edge of the hydrogen-burning main sequence.

Jarrett, T. H.; Dickman, R. L.; Herbst, W.

1994-01-01

371

The faint young sun problem. [in regulating surface temperature of early earth  

NASA Technical Reports Server (NTRS)

It is shown that the faint young sun problem was most likely solved by an increase in atmospheric CO2 concentration in the earth's atmosphere brought about by the CO2 geochemical cycle. Because the loss process for atmospheric CO2 requires liquid water, and because the earth is continually resupplying atmospheric CO2 by carbonate metamorphism, the surface temperature should never have fallen below the point at which the ocean would freeze. Indeed, the early earth may have been quite warm if carbonate metamorphism was faster and if the continents were originally smaller, so that silicate weathering was inhibited.

Kasting, James F.; Grinspoon, David H.

1991-01-01

372

The early faint sun paradox: organic shielding of ultraviolet-labile greenhouse gases  

NASA Technical Reports Server (NTRS)

Atmospheric mixing ratios of approximately 10(-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 amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing.

Sagan, C.; Chyba, C.

1997-01-01

373

Transverse motion of fragmenting faint meteors observed with the Canadian Automated Meteor Observatory  

NASA Astrophysics Data System (ADS)

Nine fragmenting, faint meteors (peak magnitude ?+1, mass <10-4 kg) were observed with the Canadian Automated Meteor Observatory (CAMO). Fragments for eight of the nine meteors exhibited significant transverse motion, perpendicular to the meteor velocity. Transverse speeds of the order 100 m s were observed, while models of aerodynamic loading predict speeds of the order 0.5 m s. Acceleration of the fragments in the transverse direction was negligible. Alternate methods of fragmentation, namely rotation and electrostatic charge accumulation, were examined through basic models to explain the observed transverse speeds. Meteoroid strengths of the order 106 Pa were derived, matching observed strengths of larger, brighter meteors.

Stokan, E.; Campbell-Brown, M. D.

2014-04-01

374

Infrared Surveys for AGN  

E-print Network

From the earliest extragalactic infrared studies AGN have shown themselves to be strong infrared sources and IR surveys have revealed new populations of AGN. I briefly review current motivations for AGN surveys in the infrared and results from previous IR surveys. The Luminous Infrared Galaxies, which in some cases house dust-enshrouded AGN, submillimeter surveys, and recent studies of the cosmic x-ray and infrared backgrounds suggest that there is a population of highly-obscured AGN at high redshift. ISO Surveys have begun to resolve the infrared background and may have detected this obscured AGN population. New infrared surveys, particularly the SIRTF Wide-area Infrared Extragalactic Legacy Survey (SWIRE), will detect this population and provide a platform for understanding the evolution of AGN, Starbursts and passively evolving galaxies in the context of large-scale structure and environment.

Harding E. Smith

2002-03-06

375

Exploration of the Saturn System by the Cassini Mission: Observations with the Cassini Infrared Spectrometer  

NASA Technical Reports Server (NTRS)

Outline: Introduction to the Cassini mission, and Cassini mission Objectives; Cassini spacecraft, instruments, launch, and orbit insertion; Saturn, Rings, and Satellite, Titan; Composite Infrared Spectrometer (CIRS); and Infrared observations of Saturn and titan.

Abbas, Mian M.

2014-01-01

376

THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. I. A CENSUS OF DUSTY YOUNG STELLAR OBJECTS AND A STUDY OF THEIR MID-INFRARED VARIABILITY  

SciTech Connect

We present a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9 deg{sup 2} in five mid-IR bands spanning 3-24 {mu}m. The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. We identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; we search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 {mu}m bands. We find that 50% of the dusty YSOs show variability. The variations are typically small ({approx}0.2 mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8 {mu}m variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots.

Megeath, S. T.; Kryukova, E. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43560 (United States); Gutermuth, R. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Muzerolle, J. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Flaherty, K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hora, J. L.; Myers, P. C.; Fazio, G. G. [Harvard Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Allen, L. E. [National Optical Astronomical Observatory, Tucson, AZ 85719 (United States); Hartmann, L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Pipher, J. L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Stauffer, J. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Young, E. T., E-mail: megeath@physics.utoledo.edu [SOFIA-Universities Space Research Association, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2012-12-01

377

DISCOVERY OF A NEW PHOTOMETRIC SUB-CLASS OF FAINT AND FAST CLASSICAL NOVAE  

SciTech Connect

We present photometric and spectroscopic follow-up of a sample of extragalactic novae discovered by the Palomar 60 inch telescope during a search for 'Fast Transients In Nearest Galaxies' (P60-FasTING). Designed as a fast cadence (1 day) and deep (g < 21 mag) survey, P60-FasTING was particularly sensitive to short-lived and faint optical transients. The P60-FasTING nova sample includes 10 novae in M 31, 6 in M 81, 3 in M 82, 1 in NGC 2403, and 1 in NGC 891. This significantly expands the known sample of extragalactic novae beyond the Local Group, including the first discoveries in a starburst environment. Surprisingly, our photometry shows that this sample is quite inconsistent with the canonical maximum-magnitude-rate-of-decline (MMRD) relation for classical novae. Furthermore, the spectra of the P60-FasTING sample are indistinguishable from classical novae. We suggest that we have uncovered a sub-class of faint and fast classical novae in a new phase space in luminosity-timescale of optical transients. Thus, novae span two orders of magnitude in both luminosity and time. Perhaps the MMRD, which is characterized only by the white dwarf mass, was an oversimplification. Nova physics appears to be characterized by a relatively rich four-dimensional parameter space in white dwarf mass, temperature, composition, and accretion rate.

Kasliwal, M. M.; Kulkarni, S. R.; Ofek, E. O.; Quimby, R. [Astronomy Department, California Institute of Technology, 105-24 Pasadena, CA 91125 (United States); Cenko, S. B. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Rau, A., E-mail: mansi@astro.caltech.edu [Max-Planck Institut fuer Extraterrestrische Physik, 85748 Garching (Germany)

2011-07-10

378

Color and Variability Characteristics of Point Sources in the Faint Sky Variability Survey  

E-print Network

We present an analysis of the color and variability characteristics for point sources in the Faint Sky Variability Survey (FSVS). The FSVS cataloged ~23 square degrees in BVI filters from ~16--24 mag to investigate variability in faint sources at moderate to high Galactic latitudes. Point source completeness is found to be >83% for a selected representative sample (V=17.5--22.0 mag, B-V=0.0--1.5) containing both photometric B, V detections and 80% of the time-sampled V data available compared to a basic internal source completeness of 99%. Multi-epoch (10--30) observations in V spanning minutes to years modeled by light curve simulations reveal amplitude sensitivities to 0.015--0.075 mag over a representative V=18--22 mag range. Periodicity determinations appear viable to time-scales of an order 1 day or less using the most sampled fields (~30 epochs). The fraction of point sources is found to be generally variable at 5--8% over V=17.5--22.0 mag. For V brighter than 19 mag, the variable population is dominated by low amplitude (<0.05 mag) and blue (B-V<0.35) sources, possibly representing a population of gamma Doradus stars. 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, gamma Doradus, and W UMa variables.

M. E. Huber; M. E. Everett; S. B. Howell

2006-04-20

379

THE DISCOVERY OF AN ULTRA-FAINT STAR CLUSTER IN THE CONSTELLATION OF URSA MINOR  

SciTech Connect

We report the discovery of a new ultra-faint globular cluster in the constellation of Ursa Minor, based on stellar photometry from the MegaCam imager at the Canada-France-Hawaii Telescope. We find that this cluster, Munoz 1, is located at a distance of 45 {+-} 5 kpc and at a projected distance of only 45' from the center of the Ursa Minor dwarf spheroidal galaxy. Using a maximum-likelihood technique we measure a half-light radius of 0.'5, or equivalently 7 pc, and an ellipticity consistent with being zero. We estimate its absolute magnitude to be M{sub V} -0.4 {+-} 0.9, which corresponds to L{sub V} = 120{sup +160}{sub -65} L{sub Sun} and we measure a heliocentric radial velocity of -137 {+-} 4 km s{sup -1} based on Keck/DEIMOS spectroscopy. This new satellite is separate from Ursa Minor by {approx}30 kpc and 110 km s{sup -1} suggesting the cluster is not obviously associated with the dSph, despite the very close angular separation. Based on its photometric properties and structural parameters we conclude that Munoz 1 is a new ultra-faint stellar cluster. Along with Segue 3 this is one of the faintest stellar clusters known to date.

Munoz, R. R.; Geha, M.; Vargas, L. C. [Astronomy Department, Yale University, New Haven, CT 06520 (United States); Cote, P.; Stetson, P. [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7 (Canada); Santana, F. A. [Departamento de Astronomia, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Simon, J. D. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Djorgovski, S. G., E-mail: rmunoz@das.uchile.cl [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States)

2012-07-01

380

Stellar Archaeology in the Galactic halo with Ultra-Faint Dwarfs: VII. Hercules  

E-print Network

We present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes 6 fundamental-mode (ab-type) and 3 first overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, = 0.68 d (sigma = 0.03 d), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening and distance to Hercules, for which we find: [Fe/H] = -2.30+-0.15 dex, E(B -V) = 0.09+-0.02 mag, and (m-M)o = 20.6+-0.1 mag, in good agreement with the literature values. We have obtained a V, B - V color-magnitude diagram (CMD) of Hercules that reaches V ~ 25 mag and extends beyond the galaxy's half-light radius over...

Musella, Ilaria; Marconi, Marcella; Clementini, Gisella; Dall'Ora, Massimo; Scowcroft, Victoria; Moretti, Maria Ida; Di Fabrizio, Luca; Greco, Claudia; Coppola, Giuseppina; Bersier, David; Catelan, Márcio; Grado, Aniello; Limatola, Luca; Smith, Horace A; Kinemuchi, Karen

2012-01-01

381

Deep Australia Telescope Large Area Survey Radio Observations of the European Large Area ISO Survey S1/Spitzer Wide-Area Infrared Extragalactic Field  

NASA Astrophysics Data System (ADS)

We have conducted sensitive (1 ? < 30 ?Jy) 1.4 GHz radio observations with the Australia Telescope Compact Array of a field largely coincident with infrared observations of the Spitzer Wide-Area Extragalactic Survey. The field is centered on the European Large Area ISO Survey S1 region and has a total area of 3.9°. We describe the observations and calibration, source extraction, and cross-matching to infrared sources. Two catalogs are presented: one of the radio components found in the image and another of radio sources with counterparts in the infrared and extracted from the literature. 1366 radio components were grouped into 1276 sources, 1183 of which were matched to infrared sources. We discover 31 radio sources with no infrared counterpart at all, adding to the class of Infrared-Faint Radio Sources.

Middelberg, Enno; Norris, Ray P.; Cornwell, Tim J.; Voronkov, Maxim A.; Siana, Brian D.; Boyle, Brian J.; Ciliegi, Paolo; Jackson, Carole A.; Huynh, Minh T.; Berta, Stefano; Rubele, Stefano; Lonsdale, Carol J.; Ivison, Rob J.; Smail, Ian

2008-04-01

382

Hubble Space Telescope Observations of the Luminous IRAS Source FSC 10214+4724: A Gravitationally Lensed Infrared Quasar  

NASA Technical Reports Server (NTRS)

With a redshift of 2.3, the IRAS source FSC 10214+4724 is apparently one of the most luminous objects known in the universe. We present an image of FSC 10214+4724 at 0.8 pm obtained with the Hubble Space Telescope (HST) WFPC2 Planetary Camera. The source appears as an unresolved (less then 0.06) arc 0.7 long, with significant substructure along its length. The center of curvature of the arc is located near an elliptical galaxy 1.18 to the north. An unresolved component 100 times fainter than the arc is clearly detected on the opposite side of this galaxy. The most straightforward interpretation is that FSC 10214+4724 is gravitationally lensed by the foreground elliptical galaxy, with the faint component a counter-image of the IRAS source. The brightness of the arc in the HST image is then magnified by approx. 100, and the intrinsic source diameter is approx. 0.0l (80 pc) at 0.25 microns rest wavelength. The bolometric luminosity is probably amplified by a smaller factor (approx. 30) as a result of the larger extent expected for the source in the far-infrared. A detailed lensing model is presented that reproduces the observed morphology and relative flux of the arc and counterimage and correctly predicts the position angle of the lensing galaxy. The model also predicts reasonable values for the velocity dispersion, mass, and mass-to-light ratio of the lensing galaxy for a wide range of galaxy redshifts. A redshift for the lensing galaxy of -0.9 is consistent with the measured surface brightness profile from the image, as well as with the galaxy's spectral energy distribution. The background lensed source has an intrinsic luminosity approx. 2 x 10(exp 13) L(solar mass) and remains a highly luminous quasar with an extremely large ratio of infrared to optical/ultraviolet luminosity.

Eisenhardt, Peter R.; Armus, Lee; Hogg, David W.; Soifer, B. T.; Neugebauer, G.; Werner, Michael W.

1996-01-01

383

Through the Looking GLASS: HST Spectroscopy of Faint Galaxies Lensed by the Frontier Fields Cluster MACSJ0717.5+3745  

NASA Astrophysics Data System (ADS)

The Grism Lens-Amplified Survey from Space (GLASS) is a Hubble Space Telescope (HST) Large Program, which will obtain 140 orbits of grism spectroscopy of the core and infall regions of 10 galaxy clusters, selected to be among the very best cosmic telescopes. Extensive HST imaging is available from many sources including the CLASH and Frontier Fields programs. We introduce the survey by analyzing spectra of faint multiply-imaged galaxies and z >~ 6 galaxy candidates obtained from the first 7 orbits out of 14 targeting the core of the Frontier Fields cluster MACSJ0717.5+3745. Using the G102 and G141 grisms to cover the wavelength range 0.8-1.7 ?m, we confirm four strongly lensed systems by detecting emission lines in each of the images. For the 9 z >~ 6 galaxy candidates clear from contamination, we do not detect any emission lines down to a 7 orbit 1? noise level of ~5 × 10-18 erg s-1 cm-2. Taking lensing magnification into account, our flux sensitivity reaches ~0.2-5 × 10-18 erg s-1cm-2. These limits over an uninterrupted wavelength range rule out the possibility that the high-z galaxy candidates are instead strong line emitters at lower redshift. These results show that by means of careful modeling of the background—and with the assistance of lensing magnification—interesting flux limits can be reached for large numbers of objects, avoiding pre-selection and the wavelength restrictions inherent to ground-based multi-slit spectroscopy. These observations confirm the power of slitless HST spectroscopy even in fields as crowded as a cluster core.

Schmidt, K. B.; Treu, T.; Brammer, G. B.; Brada?, M.; Wang, X.; Dijkstra, M.; Dressler, A.; Fontana, A.; Gavazzi, R.; Henry, A. L.; Hoag, A.; Jones, T. A.; Kelly, P. L.; Malkan, M. A.; Mason, C.; Pentericci, L.; Poggianti, B.; Stiavelli, M.; Trenti, M.; von der Linden, A.; Vulcani, B.

2014-02-01

384

Early infrared astronomy  

NASA Astrophysics Data System (ADS)

I present a short history of infrared astronomy, from the first scientific approaches of the ‘radiant heat’ in the seventeenth century to the 1970's, the time when space infrared astronomy was developing very rapidly. The beginning of millimeter and submillimeter astronomy is also covered. As the progress of infrared astronomy was strongly dependent on detectors, some details are given on their development.

Lequeux, James

2009-07-01

385

Modal Filters for Infrared Interferometry  

NASA Technical Reports Server (NTRS)

Modal filters in the approximately equal to 10-micrometer spectral range have been implemented as planar dielectric waveguides in infrared interferometric applications such as searching for Earth-like planets. When looking for a small, dim object ("Earth") in close proximity to a large, bright object ("Sun"), the interferometric technique uses beams from two telescopes combined with a 180 phase shift in order to cancel the light from a brighter object. The interferometer baseline can be adjusted so that, at the same time, the light from the dimmer object arrives at the combiner in phase. This light can be detected and its infrared (IR) optical spectra can be studied. The cancellation of light from the "Sun" to approximately equal to 10(exp 6) is required; this is not possible without special devices-modal filters- that equalize the wavefronts arriving from the two telescopes. Currently, modal filters in the approximately equal to 10-micrometer spectral range are implemented as single- mode fibers. Using semiconductor technology, single-mode waveguides for use as modal filters were fabricated. Two designs were implemented: one using an InGaAs waveguide layer matched to an InP substrate, and one using InAlAs matched to an InP substrate. Photon Design software was used to design the waveguides, with the main feature all designs being single-mode operation in the 10.5- to 17-micrometer spectral range. Preliminary results show that the filter's rejection ratio is 26 dB.

Ksendzov, Alexander; MacDonald, Daniel R.; Soibel, Alexander

2009-01-01

386

Infrared imaging of the crime scene: possibilities and pitfalls.  

PubMed

All objects radiate infrared energy invisible to the human eye, which can be imaged by infrared cameras, visualizing differences in temperature and/or emissivity of objects. Infrared imaging is an emerging technique for forensic investigators. The rapid, nondestructive, and noncontact features of infrared imaging indicate its suitability for many forensic applications, ranging from the estimation of time of death to the detection of blood stains on dark backgrounds. This paper provides an overview of the principles and instrumentation involved in infrared imaging. Difficulties concerning the image interpretation due to different radiation sources and different emissivity values within a scene are addressed. Finally, reported forensic applications are reviewed and supported by practical illustrations. When introduced in forensic casework, infrared imaging can help investigators to detect, to visualize, and to identify useful evidence nondestructively. PMID:23919285

Edelman, Gerda J; Hoveling, Richelle J M; Roos, Martin; van Leeuwen, Ton G; Aalders, Maurice C G

2013-09-01

387

Ices around Extragalactic Young Stellar Objects  

NASA Astrophysics Data System (ADS)

The infrared spectra of young stellar objects (YSOs) often show absorption features of ices. So far, almost all of the observations of ices around YSOs have been limited to Galactic objects. We here report the result of 2.5-5 ?m spectroscopy of YSOs in the Large Magellanic Cloud with infrared satellite AKARI. Absorption features of H2O, CO2 and CO ices are detected toward these extragalactic YSOs, and derived CO2/H2O ice ratio in the LMC shows a higher value than Galactic YSOs. In this paper, we discuss the different chemical conditions around extragalactic YSOs.

Shimonishi, T.; Onaka, T.; Kato, D.; Sakon, I.; Ita, Y.; Kawamura, A.; Kaneda, H.

2009-12-01

388

Unidentified infrared features in proto-planetary nebulae  

NASA Technical Reports Server (NTRS)

The discovery of an unidentified emission feature at 21 microns in the spectra of three protoplanetary nebulae is reported. These objects show large far infrared excess due to a circumstellar dust envelope surrounding a carbon rich central star. Optical, infrared and radio observations of three cool Infrared Astronomy Satellite sources suggest that they are carbon rich objects. Their low resolution spectra show a broad unidentified emission feature at 21 microns which could originate from the bending mode of a hydrocarbon molecule. The similarity of all three objects suggests that this feature is unlikely to be the result of instrumental effects.

Kwok, S.; Hrivnak, B. J.

1989-01-01

389

Hubble Space Telescope Ultraviolet and Ground-based Optical Spectropolarimetry of IRAS Quasi-stellar Objects: Dusty Scattering in Luminous Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

We present UV and optical spectropolarimetry of two highly polarized IRAS-selected quasi-stellar objects (QSOs), IRAS 13349+2438 and the broad absorption line QSO (BALQSO) IRAS 14026+4341. The polarization in both objects rises rapidly toward the blue, peaks near 3000 Å in the rest frame and remains nearly constant for shorter wavelengths. The rest frame optical polarized flux density spectra also increase rapidly toward the blue but then decrease dramatically below 3000 Å. This distinctive wavelength dependence of polarized flux shows that the polarization is produced by dust scattering. As for many Seyfert, radio, and hyperluminous infrared galaxies (HIGs), the lower polarization of the weak [O III] ??4959, 5007 lines in IRAS 13349+2438 suggests that the scattering grains lie interior to or mixed with the narrow-line gas. We construct full radiative transfer models of these systems consisting of a dusty sphere of modest optical depth illuminated axisymmetrically from within by a power-law QSO spectrum. We show that this simple model successfully reproduces the qualitative polarization properties of the objects. Despite similarities to other IRAS-selected BALQSOs, our faint object spectrograph spectropolarimetry of IRAS 13349+2438 does not reveal broad absorption lines. IRAS 14026+4341 has an Al III broad absorption line in both scattered and total flux density. We discuss these two objects in terms of both orientation and evolutionary unified schemes for QSOs, BALQSOs, and HIGs. 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.

Hines, Dean C.; Schmidt, Gary D.; Gordon, Karl D.; Smith, Paul S.; Wills, Beverley J.; Allen, Richard G.; Sitko, Michael L.

2001-12-01

390

A SEARCH FOR L/T TRANSITION DWARFS WITH Pan-STARRS1 AND WISE: DISCOVERY OF SEVEN NEARBY OBJECTS INCLUDING TWO CANDIDATE SPECTROSCOPIC VARIABLES  

SciTech Connect

We present initial results from a wide-field (30,000 deg{sup 2}) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and Wide-field Infrared Survey Explorer (WISE) surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because these objects are faint in optical bands and have near-infrared (near-IR) colors that are difficult to distinguish from background stars. To overcome these obstacles, we have cross-matched the Pan-STARRS1 (optical) and WISE (mid-IR) catalogs to produce a unique multi-wavelength database for finding ultracool dwarfs. As part of our initial discoveries, we have identified seven brown dwarfs in the L/T transition within 9-15 pc of the Sun. The L9.5 dwarf PSO J140.2308+45.6487 and the T1.5 dwarf PSO J307.6784+07.8263 (both independently discovered by Mace et al.) show possible spectroscopic variability at the Y and J bands. Two more objects in our sample show evidence of photometric J-band variability, and two others are candidate unresolved binaries based on their spectra. We expect our full search to yield a well-defined, volume-limited sample of L/T transition dwarfs that will include many new targets for study of this complex regime. PSO J307.6784+07.8263 in particular may be an excellent candidate for in-depth study of variability, given its brightness (J = 14.2 mag) and proximity (11 pc)

Best, William M. J.; Liu, Michael C.; Magnier, Eugene A.; Aller, Kimberly M.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Tonry, J. L.; Wainscoat, R. J. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Deacon, Niall R. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Dupuy, Trent J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Redstone, Joshua [Facebook, 335 Madison Ave, New York, NY 10017-4677 (United States); Price, P. A., E-mail: wbest@ifa.hawaii.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-11-10

391

A Search for L/T Transition Dwarfs with Pan-STARRS1 and WISE: Discovery of Seven Nearby Objects Including Two Candidate Spectroscopic Variables  

NASA Astrophysics Data System (ADS)

We present initial results from a wide-field (30,000 deg2) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and Wide-field Infrared Survey Explorer (WISE) surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because these objects are faint in optical bands and have near-infrared (near-IR) colors that are difficult to distinguish from background stars. To overcome these obstacles, we have cross-matched the Pan-STARRS1 (optical) and WISE (mid-IR) catalogs to produce a unique multi-wavelength database for finding ultracool dwarfs. As part of our initial discoveries, we have identified seven brown dwarfs in the L/T transition within 9-15 pc of the Sun. The L9.5 dwarf PSO J140.2308+45.6487 and the T1.5 dwarf PSO J307.6784+07.8263 (both independently discovered by Mace et al.) show possible spectroscopic variability at the Y and J bands. Two more objects in our sample show evidence of photometric J-band variability, and two others are candidate unresolved binaries based on their spectra. We expect our full search to yield a well-defined, volume-limited sample of L/T transition dwarfs that will include many new targets for study of this complex regime. PSO J307.6784+07.8263 in particular may be an excellent candidate for in-depth study of variability, given its brightness (J = 14.2 mag) and proximity (11 pc).

Best, William M. J.; Liu, Michael C.; Magnier, Eugene A.; Aller, Kimberly M.; Deacon, Niall R.; Dupuy, Trent J.; Redstone, Joshua; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Price, P. A.; Tonry, J. L.; Wainscoat, R. J.

2013-11-01

392

Obscured Activity: AGN, Quasars, Starbursts and ULIGs observed by the Infrared Space Observatory  

E-print Network

Some of the most active galaxies in the Universe are obscured by large quantities of dust and emit a substantial fraction of their bolometric luminosity in the infrared. Observations of these infrared luminous galaxies with the Infrared Space Observatory (ISO) have provided a relatively unabsorbed view to the sources fuelling this active emission. The improved sensitivity, spatial resolution and spectroscopic capability of ISO over its predecessor Infrared Astronomical Satellite (IRAS), has enabled significant advances in the understanding of the infrared properties of active galaxies. ISO surveyed a wide range of active galaxies which, in the context of this review, includes those powered by intense bursts of star-formation as well as those containing a dominant active galactic nucleus (AGN). Mid infrared imaging resolved for the first time the dust enshrouded nuclei in many nearby galaxies, while a new era in infrared spectroscopy was opened by probing a wealth of atomic, ionic and molecular lines as well as broad band features in the mid and far infrared. This was particularly useful since it resulted in the understanding of the power production, excitation and fuelling mechanisms in the nuclei of active galaxies including the intriguing but so far elusive ultraluminous infrared galaxies. Detailed studies of various classes of AGN and quasars greatly improved our understanding of the unification scenario. Far-infrared imaging and photometry also revealed the presence of a new very cold dust component in galaxies and furthered our knowledge of the far-infrared properties of faint starbursts, ULIGs and quasars. We summarise almost nine years of key results based upon ISO data spanning the full range of luminosity and type of active galaxies.

Aprajita Verma; Vassilis Charmandaris; Ulrich Klaas; Dieter Lutz; Martin Haas

2005-07-07

393

SEARCH FOR VERY LOW-MASS BROWN DWARFS AND FREE-FLOATING PLANETARY-MASS OBJECTS IN TAURUS  

SciTech Connect

The number of low-mass brown dwarfs and even free floating planetary-mass objects in young nearby star-forming (SF) regions and associations is continuously increasing, offering the possibility to study the low-mass end of the initial mass function in greater detail. In this paper, we present six new candidates for (very) low-mass objects in the Taurus SF region one of which was recently discovered in parallel by Luhman et al. The underlying data we use is part of a new database from a deep near-infrared survey at the Calar Alto observatory. The survey is more than 4 mag deeper than the Two Micron All Sky Survey and covers currently approx1.5 deg{sup 2}. Complementary optical photometry from Sloan Digital Sky Survey were available for roughly 1.0 deg{sup 2}. After selection of the candidates using different color indices, additional photometry from Spitzer/IRAC was included in the analysis. In greater detail, we focus on two very faint objects for which we obtained J-band spectra. Based on comparison with reference spectra, we derive a spectral type of L2 +- 0.5 for one object, making it the object with the latest spectral type in Taurus known today. From models, we find the effective temperature to be 2080 +- 140 K and the mass 5-15 Jupiter masses. For the second source, the J-band spectrum does not provide definite proof of the young, low-mass nature of the object, as the expected steep water vapor absorption at 1.33 mum is not present in the data. We discuss the probability that this object might be a background giant or carbon star. If it were a young Taurus member, however, a comparison to theoretical models suggests that it lies close to or even below the deuterium burning limit (<13 M{sub Jup}) as well. A first proper motion analysis for both objects shows that they are good candidates for being Taurus members.

Quanz, Sascha P. [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich (Switzerland); Goldman, Bertrand; Henning, Thomas; Brandner, Wolfgang [Max Planck Institute for Astronomy, Koenigstuhl 17, Heidelberg (Germany); Burrows, Adam [Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hofstetter, Lorne W., E-mail: quanz@astro.phys.ethz.c [Department of Physics, Princeton University, Princeton, NJ 08544 (United States)

2010-01-01

394

Faint X-ray Structure in the Crab Pulsar-Wind Nebula  

E-print Network

We report on a Chandra observation of the Crab Nebula that gives the first clear view of the faint boundary of the Crab's X-ray-emitting Pulsar Wind Nebula, or PWN. There is structure in all directions. Fingers, loops, bays, and the South Pulsar Jet all indicate that either filamentary material or the magnetic field are controlling the relativistic electrons. In general, spectra soften as distance from the pulsar increases but do not change rapidly along linear features. This is particularly true for the Pulsar Jet. The termination of the Jet is abrupt; the E side is close to an [O {\\small III}] optical filament which may be blocking propagation on this side. We argue that linear features have ordered magnetic fields and that the structure is determined by the synchrotron lifetime of particles diffusing perpendicular and parallel to the magnetic field. We find no significant evidence for thermal X-rays inside the filamentary envelope.

Seward, F D; Fesen, R A

2006-01-01

395

Spectra of faint sources in crowded fields with FRODOSpec on the Liverpool Robotic Telescope  

E-print Network

We check the performance of the FRODOSpec integral-field spectrograph for observations of faint sources in crowded fields. Although the standard processing pipeline L2 yields too noisy fibre spectra, we present a new processing software (L2LENS) that gives rise to accurate spectra for the two images of the gravitationally lensed quasar Q0957+561. Among other things, this L2LENS reduction tool accounts for the presence of cosmic-ray events, scattered-light backgrounds, blended sources, and chromatic source displacements due to differential atmospheric refraction. Our non-standard reduction of Q0957+561 data shows the ability of FRODOSpec to provide useful information on a wide variety of targets, and thus, the big potential of integral-field spectrographs on current and future robotic telescopes.

Shalyapin, Vyacheslav N

2014-01-01

396

Spectra of faint sources in crowded fields with FRODOSpec on the Liverpool Robotic Telescope  

NASA Astrophysics Data System (ADS)

We check the performance of the FRODOSpec integral-field spectrograph for observations of faint sources in crowded fields. Although the standard processing pipeline L2 yields too noisy fibre spectra, we present a new processing software (L2LENS) that gives rise to accurate spectra for the two images of the gravitationally lensed quasar Q0957+561. Among other things, this L2LENS reduction tool accounts for the presence of cosmic-ray events, scattered-light backgrounds, blended sources, and chromatic source displacements due to differential atmospheric refraction. Our non-standard reduction of Q0957+561 data shows the ability of FRODOSpec to provide useful information on a wide variety of targets, and thus, the big potential of integral-field spectrographs on current and future robotic telescopes.

Shalyapin, V. N.; Goicoechea, L. J.

397

Can a variable gravitational constant resolve the faint young Sun paradox?  

NASA Astrophysics Data System (ADS)

Solar models suggest that four billion years ago the young Sun was 25% fainter than it is today, rendering Earth's oceans frozen and lifeless. However, there is ample geophysical evidence that Earth had a liquid ocean teeming with life 4 Gyr ago. Since L? ? G7M?^5, the Sun's luminosity {L}? is exceedingly sensitive to small changes in the gravitational constant G. We show that a percent-level increase in G in the past would have prevented Earth's oceans from freezing, resolving the faint young Sun paradox. Such small changes in G are consistent with observational bounds on ?G/G. Since {L}SNI_a ? G-3/2, an increase in G leads to fainter supernovae, creating tension between standard candle and standard ruler probes of dark energy. Precisely such a tension has recently been reported by the Planck team.

Sahni, Varun; Shtanov, Yuri

2014-10-01

398

A comprehensive Maximum Likelihood analysis of the structural properties of faint Milky Way satellites  

E-print Network

We derive the structural parameters of the recently discovered very low luminosity Milky Way satellites through a Maximum Likelihood algorithm applied to SDSS data. For each satellite, even when only a few tens of stars are available down to the SDSS flux limit, the algorithm yields robust estimates and errors for the centroid, position angle, ellipticity, exponential half-light radius and number of member stars. This latter parameter is then used in conjunction with stellar population models of the satellites to derive their absolute magnitudes and stellar masses, accounting for `CMD shot-noise'. We find that faint systems are somewhat more elliptical than initially found and ascribe that to the previous use of smoothed maps which can be dominated by the smoothing kernel. As a result, the faintest half of the Milky Way dwarf galaxies (M_V>-7.5) is significantly (4-sigma) flatter (e=0.47+/-0.03) than its brightest half (M_Vsatellites, often taken to be a sign of tidal distortion, can be quantified. We find that, except for tentative evidence of distortion in CVnI and UMaII, these can be completely accounted for by Poisson scatter in the sparsely sampled systems. We consider three scenarios that could explain the rather elongated shape of faint satellites: rotation supported systems, stars following the shape of more triaxial dark matter subhalos, or elongation due to tidal interaction with the Milky Way. Although none of these is entirely satisfactory, the last one appears the least problematic, but warrants much deeper observations to track evidence of such tidal interaction.

Nicolas F. Martin; Jelte T. A. de Jong; Hans-Walter Rix

2008-05-19

399

A Comprehensive Maximum Likelihood Analysis of the Structural Properties of Faint Milky Way Satellites  

NASA Astrophysics Data System (ADS)

We derive the structural parameters of the recently discovered very low luminosity Milky Way satellites through a maximum likelihood algorithm applied to SDSS data. For each satellite, even when only a few tens of stars are available down to the SDSS flux limit, the algorithm yields robust estimates and errors for the centroid, position angle, ellipticity, exponential half-light radius and number of member stars (within the SDSS). This latter parameter is then used in conjunction with stellar population models of the satellites to derive their absolute magnitudes and stellar masses, accounting for color-magnitude diagram shot noise. Most parameters are in good agreement with previous determinations, but we now properly account for parameter covariances. However, we find that faint satellites are somewhat more elliptical than initially thought, and ascribe this effect to the previous use of smoothed maps, which can be dominated by the smoothing (round) kernel. As a result, the faintest half of the Milky Way dwarf galaxies (MV>~-7.5) is significantly (4 ?) flatter (=0.47+/-0.03) than its brightest half (MV<~-7.5, =0.32+/-0.02). From our best models, we also investigate whether the seemingly distorted shape of the satellites, often taken to be a sign of tidal distortion, can be quantified. We find that, except for tentative evidence of distortion in Canes Venatici I and Ursa Major II, these can be completely accounted for by Poisson scatter in the sparsely sampled systems. We consider three scenarios that could explain the rather elongated shape of faint satellites: rotation supported systems, stars following the shape of more triaxial dark matter subhalos, or elongation due to tidal interaction with the Milky Way. Although none of these is entirely satisfactory, the last one appears the least problematic, but obviously warrants much deeper observations to track evidence of such tidal interaction.

Martin, Nicolas F.; de Jong, Jelte T. A.; Rix, Hans-Walter

2008-09-01

400

A Systematic UBVRIJHK Survey of Nearby Galaxies to Classify Faint Galaxies from Deep HST Surveys  

NASA Astrophysics Data System (ADS)

It is well known that galaxy characteristics, such as morphology, surface brightness distribution, ellipticity, and concentration index change with bandpass, be it slowly or drastically. The rate depends on the relative importance of different physical processes, such as its (recent) star formation history and the distribution of gas and dust. As a consequence, for example, the K-correction to correct the observed fluxes of distant galaxies for bandpass shifting and wavelength stretching is strongly dependent on galaxy type and its star formation history plus dust content. To better understand the morphology and surface brightness (SB) profiles observed for the many faint galaxies seen in deep HST images out to large redshifts, similar corrections are needed for other galaxy parameters such as morphology, ellipticity and concentration index. To quantify the changes of galaxy parameters with restframe wavelength (and redshift), we present a large systematic survey in UBVRIJHK of about 400 nearby galaxies of all inclinations, Hubble types, and colors. These galaxies come from samples imaged in (a subset of) the filters UBVRIJHK by deJong et al., by Frei et al., and by Frogel et al. (for Ohio State Survey). We present the first part of a large U band imaging project with the new high throughput wide field camera at the f/1 Vatican Advanced Technology Telescope on Mt Graham, AZ. The combined UBVRIJHK sample allows us to quantify local galaxy parameters in the range 3000 Angstroms -- 2.2 mu . A modeling analysis applied to the faint field galaxies seen with HST will allow us to address the relative importance of bulge versus disk dominated galaxies, of late-type versus irregular galaxies, and of low SB galaxies versus sub-galactic clumps as a function of redshifts.

Burg, C. A. T. C.; Windhorst, R. A.; Odewahn, S. C.; de Jong, R. S.; Frogel, J. A.

1997-12-01

401

STACKING STAR CLUSTERS IN M51: SEARCHING FOR FAINT X-RAY BINARIES  

SciTech Connect

The population of low-luminosity (<10{sup 35} erg s{sup -1}) X-ray binaries (XRBs) has been investigated in our Galaxy and M31 but not further. To address this problem, we have used data from the Chandra X-Ray Observatory and the Hubble Space Telescope to investigate the faint population of XRBs in the grand-design spiral galaxy M51. A matching analysis found 25 star clusters coincident with 20 X-ray point sources within 1.''5 (60 pc). From X-ray and optical color-color plots we determine that this population is dominated by high-mass XRBs. A stacking analysis of the X-ray data at the positions of optically identified star clusters was completed to probe low-luminosity X-ray sources. No cluster type had a significant detection in any X-ray energy band. An average globular cluster had the largest upper limit, 9.23 Multiplication-Sign 10{sup 34} erg s{sup -1}, in the full band (0.3-8 keV) while on average the complete sample of clusters had the lowest upper limit, 6.46 Multiplication-Sign 10{sup 33} erg s{sup -1} in the hard band (2-8 keV). We determined average luminosities of the young and old star cluster populations and compared the results to those from the Milky Way. We conclude that deeper X-ray data are required to identify faint sources with a stacking analysis.

Vulic, N.; Barmby, P.; Gallagher, S. C., E-mail: nvulic@astro.uwo.ca [Department of Physics and Astronomy, Western University, London, ON N6A 3K7 (Canada)

2013-02-15

402

Near- and mid-infrared spectroscopic determination of algal composition  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to investigate the feasibility of using near-infrared reflectance spectroscopy (NIRS) and mid-infrared reflectan