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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

Qualification of the faint object camera  

NASA Astrophysics Data System (ADS)

The Faint Object Camera (FOC) is presently integrated as one of the five Scientific Instruments in the NASA Space Telescope (ST) which after an extensive integration and tests campaign should be launched in 1986. The Space Telescope is an observatory of 13 metres long, 4.3 metres diameter and 11,000 kilogrammes which will be placed by the Space Shuttle in a 500 kms circular orbit. The Faint Object Camera installed at the ST focal plane is a complex instrument with a total weight of 320 kgs and overall dimensions 1 x 1 x 2.2 metres. A Structural/Thermal Model (STM) and flight model of the FOC have been built. The FOC/STM was subjected to an extensive test program with for the mechanical part, sine and random vibrations, acoustic noise and modal test. On the FOC/PFM, acoustic noise only was applied for workmanship verification. With the FOC integrated now in the Space Telescope, and considering the specimen overall dimensions, limited mechanical testing will be applied at ST level which will consist of modal survey and acoustic noise. Then at the end of the test program, the overall assembly will be shipped to Kenndey Space Center and launched.

Amadieu, Patrice

1986-07-01

4

Fainting  

MedlinePLUS

... happens more than once, tell your doctor about it. If you faint when you turn your head to the side, the bones in ... than a few seconds to regain consciousness Fainting when you turn your head to the side Fainting more than once in a month ... What is the most likely cause of my fainting? Is there something I can do to ...

5

Distinguishing features of CCD astrometry of faint GEO objects  

Microsoft Academic Search

When performing the optical ground-based observations of faint objects of the geosynchronous orbit including space debris by small telescopes one is forced either to track the target object or to observe without any sort of tracking at all In both cases this produces CCD images with reference field stars appearing as trails Compared with the measurement of regular point-source stellar

V. Kouprianov

2006-01-01

6

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

7

Stellar Ultraviolet Rocket Research Program. [faint object spectrograph  

NASA Technical Reports Server (NTRS)

A 1/4 meter ultraviolet spectrometer, developed to measure the ultraviolet flux from several standard type stars was flown successfully on Aerobee rockets. The ultraviolet flux from alpha Lyr, eta U Ma, zeta Oph, delta Ori, alpha CMa, beta CMa, and alpha Leo were measured. These values agreed with the OAO data obtained by Code in the 1200 to 3400 A region to + or - 9%. The design and calibration of a faint object spectrometer for observing stars and nebula with a 3 A resolution and a 3% accuracy in a 60 second observation are discussed.

1984-01-01

8

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

SciTech Connect

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

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

2011-07-20

9

Astrometric Follow-Up of Faint Near Earth Objects  

NASA Technical Reports Server (NTRS)

The observing program at Mt. Hopkins using the 48" reflector and funded by the Near- Earth Object Observation Program continues to excel. As in the past, all requested observing time was granted. Minor improvements continue to be made. For example, the telescope is set up to track and non-sidereal rates. This allows the user to track on the target object, rather than relying exclusively on the shift- and-stack technique. Other improvements made by the staff include automatic focus routines, automatic seeing-measurement routines, and improvement in dome seeing and mirror stabilization. The net result is better focus, better seeing, and the ability to expose longer in order to acquire the faintest and most important objects. During the proposal period, this program ranked again very high worldwide in terms of faint Near Earth Objects observed. During this latest proposal cycle, fewer objects were observed than previous cycles, but this was due to the strict targeting of only the faintest observable objects. The follow-up programs of observatory codes 926 (led by P. Holvorcem) and 291 (led by Dr. B. McMillan) have greatly increased their capacity, and as a result less bright objects are in urgent need of follow-up than in years past. Even with this new object selection and additional competition, code 696 still ranked second to code 291 in terms of objects observed fainter than V = 20. Minimal scripting is now in place to allow the telescope to run autonomously for 30-45 minutes at a time.

Morgan, T. (Technical Monitor); Spahr, Timothy

2004-01-01

10

Distinguishing features of CCD astrometry of faint GEO objects  

NASA Astrophysics Data System (ADS)

When performing the optical ground-based observations of faint objects of the geosynchronous orbit including space debris by small telescopes one is forced either to track the target object or to observe without any sort of tracking at all In both cases this produces CCD images with reference field stars appearing as trails Compared with the measurement of regular point-source stellar images differential reduction of CCD images with trails may lead to the loss of positional as well as photometric accuracy Among several other sources of this problem the major difficulty is to correctly determine the centroid of each reference star and of the target GEO object Centroids obtained using the conventional center-of-mass technique are distorted by atmospheric extinction fluctuations and jitter during exposure moreover these distortions appear to be not the same for stars and for the target object which has the different visible velocity and direction An easy and straightforward way to solve this problem would be the application of the PSF fitting technique to star trails The trail-shaped PSF closely matches the observed star trail and its geometric centroid is well-defined PSF fitting technique is unaffected by position and intensity fluctuations along the trail caused by the atmosphere and swing of the telescope tube due to wind In most cases these fluctuations are the same across the whole field of view which allows one to use a single properly scaled PSF for all stars further increasing the astrometric accuracy This method is implemented in the

Kouprianov, V.

11

Image Stacking Method Application for Low Earth Orbit Faint Objects  

NASA Astrophysics Data System (ADS)

Space situational awareness is one of the most important actions for safe and sustainable space development and its utilization. Tracking and maintaining debris catalog are the basis of the actions. Current minimum size of objects in the catalog that routinely tracked and updated is approximately 10 cm in the Low Earth Orbit region. This paper proposes collaborative observation of space-based sensors and ground facilities to improve tracking capability in low Earth orbit. This observation geometry based on role-sharing idea. A space-based sensor has advantage in sensitivity and observation opportunity however, it has disadvantages in periodic observation which is essential for catalog maintenance. On the other hand, a ground facility is inferior to space-based sensors in sensitivity however; observation network composed of facilities has an advantage in periodic observation. Whole observation geometry is defined as follows; 1) space-based sensors conduct initial orbit estimation for a target 2) ground facility network tracks the target based on estimated orbit 3) the network observes the target periodically and updates its orbit information. The second phase of whole geometry is based on image stacking method developed by the Japan aerospace exploration agency and this method is verified for objects in geostationary orbit. This method enables to detect object smaller than a nominal size limitation by stacking faint light spot along archived time-series frames. The principle of this method is prediction and searching target's motion on the images. It is almost impossible to apply the method to objects in Low Earth Orbit without proper orbit information because Low Earth Orbit objects have varied orbital characteristics. This paper discusses whether or not initial orbit estimation results given by space-based sensors have enough accuracy to apply image stacking method to Low Earth Orbit objects. Ground-based observation procedure is assumed as being composed of telescopes conduct chasing observation for the estimated apparent trajectory and stack the images based on the relative apparent motion search for true object. Therefore accuracy evaluation for initial orbit estimation result means to verify that apparent motions of true object are able to being searched. The current image stacking method applied for geostationary orbit based on assumptions that apparent motion can be treated as straight lines. Thus the linearity and uniformity assessment of the apparent motion in ground-based tracking observation using initial orbit estimation result is required. This paper introduces the apparent motion prediction result with reasonably assumed orbit estimation errors. The ground observatories are assumed to be located around the polar regions. Then this paper discusses image stacking feasibility for the apparent motion based on space-based orbit estimation result.

Tagawa, M.; Matsumoto, H.; Yanagisawa, T.; Kurosaki, H.; Oda, H.; Kitazawa, Y.; Hanada, T.

2013-09-01

12

A faint object spectrograph for the William Herschel Telescope  

NASA Astrophysics Data System (ADS)

The design and performance of the FOS-2 faint-object spectrograph for the Herschel Telescope at the Observatorio del Roque de los Muchachos are described and illustrated with diagrams and drawings. The FOS-2 has an image scale of 223 microns/arcsec at the slit and features a cryostat-cooled 385 x 578-pixel CCD detector with 22-micron-sq pixels, operating with resolution 1.5 pixels and dispersion 8.73 A/pixel at 460-970 nm (first order) or 4.32 A/pixel at 350-490 nm (second order). The high-efficiency optical system is of the type described by Wynne (1982) and operates in the diverging f/11 Cassegrain beam without a collimator. Overall system efficiency in first order with a 5-arcsec slit has a peak at 16 percent at 700 nm and remains above 1 percent at all wavelengths imaged by the CCD; in second order the peak efficiency is about 3 percent at 490 nm and remains above 1 percent except below 370 nm. The mechanical system, the control and data acquisition procedures, and the data-reduction software are briefly discussed.

Allington-Smith, J. R.; Breare, J. M.; Ellis, R. S.; Parry, I. R.; Webster, J.

1990-07-01

13

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

14

a SUBARU Archival Search for Faint Trans-Neptunian Objects  

NASA Astrophysics Data System (ADS)

We present the results of a survey for trans-Neptunian objects (TNOs) based on Subaru archival images, originally collected by Sheppard et al. in 2005 as part of a search for irregular satellites of Uranus. The survey region covers 2.8 deg2, centered on Uranus and observed near opposition on two adjacent nights. Our survey reaches half its maximum detection efficiency at R = 25.69 ± 0.01. The objects detected correspond to 82 TNOs, five Centaurs, and five irregular satellites. We model the cumulative number of TNOs brighter than a given apparent magnitude with both a single power law (SPL) and a double power law (DPL). The best-fit SPL, with one object per square degree at magnitude R 0 = 22.6+0.3 -0.4 and a slope of ? = 0.51+0.5 -0.6, is inconsistent with the results of similar searches with shallower limiting magnitudes. The best-fit DPL, with a bright-end slope ?1 = 0.7+0.2 -0.1, a faint-end slope ?2 = 0.3+0.2 -0.2, a differential number density at R = 23?23 = 2.0+0.5 -0.5, and a magnitude break in the slope at R eq = 24.3+0.8 -0.1, is more likely than the SPL by a Bayes factor of ~26. This is the first survey with sufficient depth and areal coverage to identify the magnitude at which the break occurs without relying on the results of other surveys. We estimate barycentric distances for the 73 objects that have 24 h arcs; only two have heliocentric distances as large as ~50 AU. We combine the distribution of observed distances with the size distribution that corresponds to a DPL luminosity function to set a tight constraint on the existence of a distant TNO population. We can exclude such a population at 60 AU, with 95% confidence, assuming it has the same size distribution and albedo as the observed TNOs, if it exceeds 8% of mass of the observed TNOs. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Fuentes, Cesar I.; Holman, Matthew J.

2008-07-01

15

Two newly discovered S stars in a list of faint red objects  

NASA Technical Reports Server (NTRS)

A list of 103 faint red stars in a 0.7-square-degree area located near NGC 6820/23 on the galactic plane in the constellation Vulpecula is presented. The stars were chosen from Near Infrared Photographic Sky Survey visual and near-IR photographic pairs and were selected for their visual faintness as well as their red colors. Positions, approximate magnitudes, and finding charts for these stars are presented. It is noted that two members of the list, 1548C858 and 1548C869, have already been determined to be faint, pure S stars.

Turnshek, D. E.; Turnshek, D. A.; Boeshaar, P. C.; Craine, E. R.

1983-01-01

16

Strategies for Imaging Faint Extended Sources in the Near-Infrared  

E-print Network

Quantitative information about variations in the background at J and K' are presented and used to develop guidelines for the acquisition and reduction of ground-based images of faint extended sources in the near-infrared, especially those which occupy a significant fraction of the field of view of a detector or which are located in areas crowded with foreground or background sources. Findings are based primarily upon data acquired over three photometric nights with the 3.6x3.6 arcmin CFHT-IR array on the Canada-France-Hawaii Telescope atop Mauna Kea. Although some results are specific to CFHT, overall conclusions should be useful in guiding observing and reduction strategies of extended objects elsewhere.

Ovidiu Vaduvescu; Marshall L. McCall

2004-04-16

17

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

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

18

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

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

19

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

NASA Astrophysics Data System (ADS)

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

Trilling, David E.; Brown, Robert H.

2000-11-01

20

A survey for faint variable objects in SA 57  

Microsoft Academic Search

Nine Mayall 4 m prime-focus Kodak IIIa-J plates spanning an 11-yr baseline are analyzed in a uniform manner for the detection of variable objects to B = 22.6 at the level of Sigma of about 0.1 mag. Techniques are developed that succeed in independently finding objects already known to be variable, namely a sample of QSOs. Few additional objects were

Dario Trevese; Giancarlo Pittella; Richard G. Kron; David C. Koo; Matthew Bershady; Osservatorio Astronomico Roma; WI Williams Bay; CA Santa Cruz

1989-01-01

21

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

22

A faint-object grism spectrograph with multiple slits and CCD detector  

NASA Technical Reports Server (NTRS)

A high-efficiency spectrograph for research on faint astronomical objects has been successfully built and is in regular use on the Multiple-Mirror Telescope (MMT). It is equipped with a motorized multi-slit mechanism to allow simultaneous observations of several objects. The combination of high throughput, multiple object capability, and low-noise CCD detector has allowed routine work to be extended to objects of V magnitude 23 and fainter.

Geary, John C.; Huchra, John P.; Latham, David W.

1986-01-01

23

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.

2014-11-01

24

The Phoenix Survey: optical and near-infrared observations of faint radio sources  

Microsoft Academic Search

Using a deep Australia Telescope Compact Array (ATCA) radio survey covering an area of ~3 deg2 to a 4sigma sensitivity of >= 100 muJy at 1.4 GHz, we study the nature of faint radio galaxies. About 50 per cent of the detected radio sources are identified with an optical counterpart revealed by CCD photometry to mR=22.5 mag. Near-infrared (K-band) data

A. Georgakakis; B. Mobasher; L. Cram; A. Hopkins; C. Lidman; M. Rowan-Robinson

1999-01-01

25

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

26

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

27

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

28

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

29

The Faint Object Telescope - A rocket instrument for far-ultraviolet spectrophotometry of galaxies and quasars  

Microsoft Academic Search

An instrument consisting of a 0.4-meter diameter f\\/15 telescope, a concave grating spectrometer, and a micro-channel plate detector has been constructed in order to carry out moderate resolution (about 10 A) spectrophotometry of faint extra-galactic objects in the 1200-1700 A spectral band. In its first flight, aboard a NASA Black Brant VC rocket launched from White Sands Missile Range on

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

1977-01-01

30

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

31

WFC3 Spectroscopy of Faint Young Companions to Orion Young Stellar Objects  

NASA Astrophysics Data System (ADS)

We propose G141 grism spectroscopy of faint young companions to young stellar objects (YSOs) in the Orion molecular cloud which were recently identified in a WFC3/HST 1.6 micron survey of 320 YSOs in Orion. We will target the ten faintest companions detected between 80-1000 AU which have F160W magnitudes between 19 and 22.6 mag; these are too faint to obtain spectra from ground-based telecopes. The faint magnitudes of these ten companions suggest that they have masses as small as 5 Mjupiter depending on their age and reddening. To determine spectral types and masses for these sources, we will use grism spectroscopy to detect broad water features in the photospheric spectrum. These observations are part of a coordinated spectroscopy campaign; the remaining 50 brighter companions will be observed using spectrographs on the IRTF and SUBARU. These data will constrain the companion mass function at projected separations of 80-1000 AU from Orion young stellar objects. Given their faint magnitudes, as many as half of the 60 companions may be below the Hydrogen burning limit. With spectra, we can determine whether there is an excess of sub-stellar companions relative to the field IMF at these separations; the detection of such an excess would be evidence for the formation of sub-stellar objects in the outer regions of protostellar disks. Furthermore, the observed fraction of companions at these separations increases from 7.8 to 14.1% between low and high stellar density region in Orion; suggesting that the formation of multiple sytems is dependent on the birth environment. With spectra, we can explore the dependence of the companion mass function on the birth environment.

Megeath, S.

2014-10-01

32

The Faint Stellar Object SDSS J1257+3419 is a Dark Matter Dominated System  

E-print Network

A recent study has revealed SDSS J1257+3419 is either a faint and small dwarf galaxy or a faint and widely extended globular cluster. In this Letter, the author suggests this stellar system is a dwarf spheroidal (dSph). Adopting an observational relation between binding energy and mass of old stellar systems, we derive a relation between mass and size of dSphs by assuming that they are dark matter dominated and virialized objects. Letting half-light radius represent size of SDSS J1257+3419, we find that its mass is $\\sim 7\\times 10^6$ solar mass. This indicates mass-to-light ratio ($M/L$) of SDSS J1257+3419 is about 1000 in the solar unit. This large $M/L$ is expected from a Mateo plot of dSphs. Thus, we insist SDSS J1257+3419 is a dSph.

Hideyuki Kamaya

2007-11-07

33

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

34

Astrometric and Photometric Follow-up of Faint Near Earth Objects  

NASA Technical Reports Server (NTRS)

During the period April 2003 - April 2005, roughly 150 different faint NEO's were observed using the 1.2-m telescope at Mt. Hopkins. Among these were a couple of spacecraft/radar targets, including support observations in support of the Deep Impact mission. While not strictly an NEO target, comet P/Tempel 1 was nonetheless observed as an object of very high importance. During this time and independent contractor, Kyle Smalley, was trained in the use of the telescope and provided some basic software support for the project.

Morgan, T. (Technical Monitor); Spahr, Timothy

2005-01-01

35

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

NASA Technical Reports Server (NTRS)

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.

1994-01-01

36

H? Dots: A Catalog of Faint Emission-line Objects Discovered in Narrowband Images  

NASA Astrophysics Data System (ADS)

During a wide-field narrowband H? 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?), 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] ?5007) redshift into our narrowband filter. We have carried out a systematic search for these "H? dots" in over 200 15 × 15 arcmin fields. To date we have cataloged 61 candidate emission-line sources in roughly 11.7 deg2. The sample has a median R magnitude of 19.5, and detects objects as faint as R = 22.6. Follow-up spectroscopy reveals that ~85% of the candidates are bona fide emission-line objects, with roughly 60% of the real sources being lower-redshift objects (detection via H?) 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 ? 0.33.

Kellar, Jessica A.; Salzer, John J.; Wegner, Gary; Gronwall, Caryl; Williams, Anna

2012-06-01

37

Far-infrared properties of submillimeter and optically faint radio galaxies  

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

38

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

39

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

40

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

41

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

42

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

43

In-orbit performance of the COSTAR-corrected Faint Object Camera  

NASA Technical Reports Server (NTRS)

The improvements due to the Corrective Optics Space Telescope Axial Replacement (COSTAR) on imaging with the Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) are presented. The encircled energy performance is dramatically improved, such that 85% of the total light in the Point Spread Function (PSF) is now enclosed within a circle of radius 0.1 sec at 486 nm wavelength, compared to 18% in the spherically aberrated PSF. This is equivalent to a sensitivity increase of 1.6 mag. The effective angular resolution is also improved from 66 to 43 mas at 486 nm. These improvements are slightly offset by a 20% lower total throughput at visible wavelengths. The plate scale is changed from 22.3 mas/pixel to 14.35 mas/pixel, resulting in a decrease in the field of view from 11 x 11/sq arcsec to 7.3 x 7.3/sq arcsec for the workhorse 512 x 512 format.

Jedrzejewski, R. I.; Hartig, G.; Jakobsen, P.; Crocker, J. H.; Ford, H. C.

1994-01-01

44

Electron-Multiplying CCD Imaging: Effectiveness for Stellar Occultations by Faint Objects  

NASA Astrophysics Data System (ADS)

Our Portable Occultation, Eclipse, and Transit Systems (POETS; Souza et al. 2006, PASP 118, 1550) have been successfully employed for multiple stellar occultation observations: (i) four systems obtained data in South America during the 11 July 2005 occultation of C313.2 (2UCAC 26257135) by Charon (Gulbis et al. 2006, Nature 439, 48; Person et al. 2006, AJ 132 1575); (ii) four systems obtained data in Australia during the 2006 June 12 occultation of P384.2 (2UCAC 26039859) by Pluto (Elliot et al. 2007, AJ 134, 1), and (iii) three systems were utilized in the Southwestern U.S. for the 2007 March 18 occultation of P445.2 (2UCAC 25823784) by Pluto (Person et al. 2007, this meeting). Pluto and Charon have apparent V magnitudes of 14 and 16, and the stars for these events had UCAC magnitudes of 14.99 to 15.25. These events were bright enough to achieve fair to excellent signal-to-noise ratios (SNRs) at cadences between 2 and 10 Hz by using "conventional” camera modes. POETS also possess electron-multiplying (EM) readout modes, which we have not yet employed for occultation observations because conventional modes have been more than adequate. EM modes have higher read noise, generate an excess noise factor, and limit dynamic range; however, signal can be increased by a factor of up to 1000x, and read noise is effectively eliminated at high EM gain. Here, we explore the benefits and disadvantages of using EM capability for observations of stellar occultations by faint bodies. We focus on prospective occultations by Kuiper Belt objects, predictions of which are increasingly numerous as fainter stars are considered. We identify regimes in which EM modes are most effective by analyzing SNR as a function of exposure time and object/star magnitudes. This work is supported by NASA Planetary Astronomy grants NNG04GF25G and NNG04GE48G.

Gulbis, Amanda A.; Elliot, J. L.; Person, M. J.; Souza, S. P.; Babcock, B. A.; Pasachoff, J. M.; McKay, A. J.; Zuluaga, C. A.

2007-10-01

45

Hubble Space Telescope: Faint object spectrograph instrument handbook. Version 1.1  

NASA Technical Reports Server (NTRS)

The Faint Object Spectrograph (FOS) has undergone substantial rework since the 1985 FOS Instrument Handbook was published, and we are now more knowledgeable regarding the spacecraft and instrument operations requirements and constraints. The formal system for observation specification has also evolved considerably, as the GTO programs were defined in detail. This supplement to the FOS Instrument Handbook addresses the important aspects of these changes, to facilitate proper selection and specification of FOS observing programs. Since the Handbook was published, the FOS red detector has been replaced twice, first with the best available spare in 1985 (which proved to have a poor, and steadily degrading red response), and later with a newly developed Digicon, which exhibits a high, stable efficiency and a dark-count rate less than half that of its predecessors. Also, the FOS optical train was realigned in 1987-88 to eliminate considerable beam-vignetting losses, and the collimators were both removed and recoated for greater reflectivity. Following the optics and detector rework, the FOS was carefully recalibrated (although only ambient measurements were possible, so the far-UV characteristics could not be re-evaluated directly). The resulting efficiency curves, including improved estimates of the telescope throughput, are shown. A number of changes in the observing-mode specifications and addition of several optional parameters resulted as the Proposal Instructions were honed during the last year. Target-brightness limitations, which have only recently been formulated carefully, are described. Although these restrictions are very conservative, it is imperative that the detector safety be guarded closely, especially during the initial stages of flight operations. Restrictions on the use of the internal calibration lamps and aperture-illumination sources (TA LEDs), also resulting from detector safety considerations, are outlined. Finally, many changes have been made to the instructions for target acquisition specification.

Ford, Holland C. (editor)

1990-01-01

46

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

47

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

48

VizieR Online Data Catalog: Infrared-faint radio sources catalog (Collier+, 2014)  

NASA Astrophysics Data System (ADS)

The 20cm radio data come from the Unified Radio Catalog (URC) compiled by Kimball & Ivezic (2008AJ....136..684K). This radio catalogue combines data from the National Radio Astronomy Observatory (NRAO) VLA Sky Survey (NVSS; Condon et al., 1998, Cat. VIII/65), Faint Images of the Radio Sky at Twenty Centimeters (FIRST; Becker, White & Helfand, 1995, cat. VIII/92), Green Bank 6cm survey (GB6; Gregory et al., 1996, Cat. VIII/40), the Westerbork Northern Sky Survey (WENSS; Rengelink et al. 1997; de Bruyn et al. 2000, Cat. VIII/62) and the Sloan Digital Sky Survey Data Release 6 (SDSS DR6; Adelman-McCarthy et al., 2008, Cat. II/282). We use updated NVSS and FIRST data from the URC version 2.0 (Kimball & Ivezic, in preparation), which includes a number of new sources as well as updated positions and flux densities. The IR data come from WISE (Wright et al. (WISE Team) 2009, Cat. II/311), which is an all-sky survey centred at 3.4, 4.6, 12 and 22um (referred to as bands W1, W2, W3 and W4), with respective angular resolutions of 6.1, 6.4, 6.5 and 12.0-arcsec (full width at half-maximum, FWHM), and typical 5? sensitivity levels of 0.08, 0.11, 1 and 6mJy, with sensitivity increasing towards the ecliptic poles. (1 data file).

Collier, J. D.; Banfield, J. K.; Norris, R. P.; Schnitzeler, D. H. F. M.; Kimball, A. E.; Filipovic, M. D.; Jarrett, T. H.; Lonsdale, C. J.; Tothill, N. F. H.

2014-11-01

49

Faint Object Spectrograph Spectra of the UV Emission Lines in NGC 5558: Detection of Strong Narrow Components  

NASA Technical Reports Server (NTRS)

Ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 were obtained with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope on 1992 July 5, when the UV continuum and broad emission lines were at their lowest ever observed level. The high resolution of the spectra, relative to previous UV observations, and the low state of NGC 5548 allow the detection and accurate measurement of strong narrow components of the emission lines of Ly alpha, C IV 1549, and C III 1909. Isolation of the UV narrow components enables a detailed comparison of narrow-line region (NLR) properties in Seyfert 1 and 2 galaxies, and removal of their contribution is important for studies of the broad-line region (BLR). Relative to the other narrow lines, C IV 1549 is much stronger in NGC 5548 than in Seyfert 2 galaxies, and Mg II 2798 is very weak or absent.

Crenshaw, D. Michael; Boggess, Albert; Wu, Chi-Chao

1993-01-01

50

Spaced based infrared detection and characterization of near earth objects  

Microsoft Academic Search

An infrared space-based survey system would be an invaluable adjunct to the ground based visible searches for the discovery of Near Earth Objects (NEOs). It would significantly increase the discovery rate of NEOs and would have unique capabilities to probe their physical character. An infrared NEO survey compensates for the bias of visible searches to preferentially discover high albedo objects

Stephan D. Price; Michael P. Egan

2001-01-01

51

Radio-faint BL Lac objects and their impact on the radio/gamma-ray connection  

NASA Astrophysics Data System (ADS)

Radio and gamma-ray emissions in Active Galactic Nuclei (AGNs) are both related to the presence of relativistic particles in jets. With the advent of the Fermi Large Area Telescope (LAT), and thanks to its large sensitivity up to several GeV, many observational results are changing our understanding of these phenomena. BL Lac objects, which made up only a fraction of the known extragalactic gamma-ray source population before Fermi, have now become the most abundant class. However, since they are relatively weak radio sources, most of them are poorly known as far as their parsec scale structure and multi-wavelength properties are concerned. For this reason, we have selected a complete sample of 42 low redshift BL Lacs (independently of their gamma-ray properties) to study with a multi-wavelength (radio, optical, X-ray, gamma-ray) approach. Here, we present results and images of sources in the sample (most of which have never been observed before), using new VLBA observations at 8 and 15 GHz. Beyond this sample of BL Lacs, the population of gamma-ray AGNs has also dramatically enlarged in the Fermi era, permitting us to discuss the presence of a correlation between radio and gamma-ray properties with improved statistical significance. We explore the radio-gamma relation with several hundreds sources and using both simultaneous and archival radio data, thus tackling the impact of time variability.

Giroletti, Marcello; Pavlidou, V.; Reimer, A.; Taylor, G. B.; Tosti, G.; Giovannini, G.; Casadio, C.; Liuzzo, E.; Tamburri, S.

2012-05-01

52

Improving infrared images for standoff object detection  

Microsoft Academic Search

The ability to detect dangerous objects (such as improvised explosive devices) from a distance is important in security and military environments. Standoff imaging can produce images that have been degraded by atmospheric turbulence, movement, blurring and other factors. The number and size of pixels in the imaging sensor can also contribute to image degradation through under-sampling of the image. Establishing

Katherine Hanton; Marcus A. Butavicius; Ray Johnson; Jadranka Sunde

2009-01-01

53

Infrared system for monitoring movement of objects  

DOEpatents

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

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

1991-01-01

54

Infrared system for monitoring movement of objects  

DOEpatents

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

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

1991-04-30

55

Visible and infrared photometry of Kuiper Belt objects: searching for evidence of trends  

E-print Network

Visible and infrared photometry of Kuiper Belt objects: searching for evidence of trends Neil Mc. © 2003 Elsevier Science (USA). All rights reserved. Keywords: Kuiper Belt objects; Photometry; Infrared

Sheppard, Scott S.

56

A first sample of faint radio sources with virtually complete redshifts: I. Infrared images, the Hubble diagram, and the alignment effect  

E-print Network

We have obtained redshifts and infrared images for a sample of faint B2/6C radio sources whose fluxes are about six times fainter than those of sources in the bright 3C sample. We now have unambiguous redshifts for 90% of the sources, making this the first faint radio sample with such complete redshift information. We find that the infrared Hubble diagrams (K versus z) of the 3C sample and the B2/6C sample are similar at a low redshift (z < 0.6), but by a redshift about 1 the 6C/B2 galaxies are on average about 0.6 mags fainter in the K-band than 3C galaxies at the same redshift. This suggests that the bright K-magnitudes of 3C galaxies at a redshift of about 1 are not the result of stellar evolution, but of a correlation between infrared and radio luminosity. We also find that the infrared stuctures of B2/6C galaxies at z=1 are less clearly aligned with their radio structures than 3C galaxies at this redshift, implying that the strength of the alignment effect depends on radio luminosity. Finally, above a redshift of 2 we find that the dispersion in the K-z relation of the B2/6C sample is about 2.7 times greater than that at low redshift, a result which is expected if at these redshifts we are beginning to penetrate into the epoch in which radio galaxies formed.

Stephen Eales; Steve Rawlings; Duncan Law-Green; Garret Cotter; Mark Lacy

1997-01-07

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

Mid-infrared Spectral Variability Atlas of Young Stellar Objects  

NASA Astrophysics Data System (ADS)

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 ?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 ?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 ?m silicate emission, the variability of the 6-8 ?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. This work is based on observations made with the Infrared Space Observatory (ISO) and with the Spitzer Space Telescope. ISO is an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands, and UK) and with the participation of ISAS and NASA. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

Kóspál, Á.; Ábrahám, P.; Acosta-Pulido, J. A.; Dullemond, C. P.; Henning, Th.; Kun, M.; Leinert, Ch.; Moór, A.; Turner, N. J.

2012-08-01

59

Hubble Space Telescope faint object spectrograph Quasar Absorption System Snapshot Survey (AbSnap). 1: Astrometric optical positions and finding charts of 269 bright QSO  

NASA Technical Reports Server (NTRS)

We present finding charts and optical positions accurate to less than 1 arcsec for 269 bright (V less than or = 18.5) Quasi-Stellar Objects (QSOs). These objects were selected as candidates for the Hubble Space Telescope (HST) Quasar Absorption System Snapshot Survey (AbSnap), a program designed to use the Faint Object Spectrograph (FOS) to obtain short exposure ultraviolet (UV) spectra of bright QSOs. Many quasars were included because of their proximity to bright, low redshift galaxies and positions of these QSOs are measured accurately for the first time. Data were obtained using the digitized sky survey produced by the Space Telescope Science Institute's Guide Stars Selection System Astrometric Support Program.

Bowen, David V.; Osmer, Samantha J.; Blades, J. Chris; Tytler, David; Cottrell, Lance; Fan, Xiao-Ming; Lanzetta, Kenneth M.

1994-01-01

60

Hubble Space Telescope Near-infrared and Optical Imaging of Faint Radio Sources in the Distant Cluster Cl0939+4713  

E-print Network

We present deep Hubble Space Telescope NICMOS near-infrared and WFPC2 optical imaging of a small region in the core of the distant rich cluster Cl0939+4713 (z=0.41). We compare the optical and near-infrared morphologies of cluster members and find apparent small-scale optical structures within the galaxies which are absent in the near-infrared. We conclude that strong dust obscuration is a common feature in the late-type galaxies in distant clusters. We then concentrate on a sample of ten faint radio galaxies lying within our NICMOS field and selected from a very deep 1.4-GHz VLA map of the cluster with a 1sigma flux limit of 9uJy. Using published data we focus on the spectral properties of the eight radio-selected cluster members and show that these comprise a large fraction of the post-starburst population in the cluster. The simplest interpretation of the radio emission from these galaxies is that they are currently forming massive stars, contradicting their classification as post-starburst systems based on the optical spectra. We suggest that this star formation is hidden from view in the optical by the same obscuring dust which is apparent in our comparison on the optical and near-infrared morphologies of these galaxies. We caution that even in the restframe optical the effects of dust cannot be ignored when comparing samples of distant galaxies to low-redshift systems, particularly if dust is as prevelant in distant galaxies as appears to be the case in our study.

Ian Smail; G. E. Morrison; M. E. Gray; F. N. Owen; R. J. Ivison; J. -P. Kneib; R. S. Ellis

1999-05-27

61

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

NASA Astrophysics Data System (ADS)

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.

1990-07-01

62

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

63

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

64

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

65

Near-infrared spectroscopy of primitive solar system objects  

NASA Astrophysics Data System (ADS)

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

1994-05-01

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

Infrared Variation of Radio Selected BL Lacertae Objects  

E-print Network

In this paper, the historical infrared (JHK) data compiled from the published literature are presented in electronic form for 40 radio selected BL Lacertae objects (RBLs) for the first time. Largest variations are found and compared with the largest optical variation. Relations between color index and magnitude and between color-color indices are discussed individually. For the color-magnitude relation, some objects (0048-097, 0735+178, 0851+202, 1215+303, 1219+285, 1749+096, and perhaps 0219+428, 0537-441, 1514-241) show that color index increases with magnitude indicating that the spectrum flattens when the source brightens while some other objects (0754+100, 1147+245, 1418+546, and 1727+502) perhaps show an opposite behaviour, while remaining objects do not show any clear tendency; For color-color relation, it is found common that (J-K) is closely correlated with (J-H) while (J-H) is not correlated with (H-K).

J. H. Fan; R. G. Lin

1999-08-10

68

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

69

A Proposed Infrared Search for Artificial Kuiper Belt Objects  

NASA Astrophysics Data System (ADS)

As pointed out previously, large solar-sail spacecraft unfurled near the Sun could traverse the separation between the solar system and Alpha Centauri on voyages of about 1,000-year duration. Since stars approach our Sun within 1-2 light years at intervals of about 105 years, even contemporary technology would allow 250-500 year colonization ventures to our solar system from as many as 5 x 104 other stars since the formation of our solar system. If one of 10,000 or so stars in the Milky Way Galaxy is home to a long-lived technological civilization, extraterrestrial (ET) colonies may exist in our solar system. Papagianis has suggested that an infrared (IR) survey of asteroidal solar system objects may reveal the presence of ET colonies by IR-excess. This paper addresses many issues of performing such a search of Kuiper Belt objects (KBOs) including photometric filter characteristics and calibrations, reflected and (projected) radiated IR fluxes and colour indices from natural and artificial KBOs, and KBO IR observability using moderate-sized telescopes. it is demonstrated that the observed IR excesses of Centaur objects is almost certainly not artificial.

Matloff, G. L.

70

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

71

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

72

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

73

Cataloged infrared sources in NIPSS data. I - The RSO 1 catalog. [Near Infrared Photographic Sky Survey Red Stellar Objects  

NASA Technical Reports Server (NTRS)

A small number of selected near-infrared and visual photographic pairs from the Steward Observatory Near Infrared Photographic Sky Survey have been examined for content of stars more red than (V-I) of about 2.5 magnitudes. A simple manual extraction of these objects was carried out as a part of a preliminary evaluation of survey data and techniques for reducing it; the resulting list has been compiled as the first installment of a Catalog of Red Stellar Objects (Craine et al. 1979). Results of a cross correlation of this catalog with the IRC, AFGL, and EIC infrared catalogs are here presented. The results indicate that these photographs may be particularly useful for purposes of optical identification of short-wavelength infrared sources to limits much fainter than represented by presently existing infrared catalogs.

Horner, V. M.; Craine, E. R.

1980-01-01

74

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

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

75

Near-infrared spectra of 12 Near-Earth Objects  

Microsoft Academic Search

We present a number of spectra of Near-Earth Objects taken in the period 1998 2003 with two different instruments (CGS4 and UIST) on the UKIRT telescope. Since observations with CGS4 require multiple spectral fragments to be observed sequentially and then spliced together we assess the reliability of this technique using comparisons between multiple observations of the same object, between observations

John K. Davies; Alan W. Harris; Andrew S. Rivkin; Stephen D. Wolters; Simon F. Green; Neil McBride; Rita K. Mann; Tom H. Kerr

2007-01-01

76

Automatic detection of small objects from their infrared state-of-polarization vectors.  

PubMed

A technique for automatic detection of targets from their infrared signature's state-of-polarization vector is described. The bounds on the Bayesian total probability of errors are estimated from the observed Stokes vector imagery and used as metrics for separating targets from background clutter. The performance of the proposed approach for objects under various geometries is studied in terms of receiver operating characteristic curves. The new results, which have been obtained from data from the U.S. Air Force's Infrared Modeling and Analysis polarimetric infrared simulation tool, indicate the usefulness of polarimetric infrared signatures for the automatic detection of small targets. PMID:12696606

Sadjadi, Firooz A; Chun, Cornell S L

2003-04-01

77

Near-infrared spectra of 12 Near-Earth Objects  

Microsoft Academic Search

We present a number of spectra of Near-Earth Objects taken in the period 1998–2003 with two different instruments (CGS4 and UIST) on the UKIRT telescope. Since observations with CGS4 require multiple spectral fragments to be observed sequentially and then spliced together we assess the reliability of this technique using comparisons between multiple observations of the same object, between observations of

John K. Davies; Alan W. Harris; Andrew S. Rivkin; Stephen D. Wolters; Simon F. Green; Neil McBride; Rita K. Mann; Tom H. Kerr

2007-01-01

78

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

79

Infrared detection, recognition and identification of handheld objects  

NASA Astrophysics Data System (ADS)

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

Adomeit, Uwe

2012-10-01

80

GIRMOS: an infrared multi-object spectrograph for Gemini  

Microsoft Academic Search

Gemini have funded a design study to investigate the technologies needed in a versatile multi-object spectrograph for IR astronomy. We report on our investigations into wide- field spectroscopy using multiple integral-field units (MIFUs) to match particular areas of interest to the available detector(s). Such technologies enable integral field spectroscopy of several targets over a much wider field than can be

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

2000-01-01

81

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

82

Far-infrared observations of the exciting stars of Herbig-Haro objects. III - Circumstellar disks  

NASA Astrophysics Data System (ADS)

Far-infrared observations of the exciting stars of Herbig-Haro objects are presented that (1) show these stars to be of low luminosity; (2) indicate that it is not usual for these objects themselves to be visible at far-infrared wavelengths; and (3) demonstrate the existence of spatially resolved, physically large, potentially disklike structures. These latter structures are resolved perpendicular to the directions of flow from the stars, but not parallel to the flows. In addition to these general properties, two new HH-exciting stars were discovered by searching along the extrapolated proper motion vectors for these HHs; and the jetlike object 'DG Tau B' was also detected.

Cohen, M.; Harvey, P. M.; Schwartz, R. D.

1985-09-01

83

Far-infrared observations of the exciting stars of Herbig-Haro objects. III - Circumstellar disks  

NASA Technical Reports Server (NTRS)

Far-infrared observations of the exciting stars of Herbig-Haro objects are presented that (1) show these stars to be of low luminosity; (2) indicate that it is not usual for these objects themselves to be visible at far-infrared wavelengths; and (3) demonstrate the existence of spatially resolved, physically large, potentially disklike structures. These latter structures are resolved perpendicular to the directions of flow from the stars, but not parallel to the flows. In addition to these general properties, two new HH-exciting stars were discovered by searching along the extrapolated proper motion vectors for these HHs; and the jetlike object 'DG Tau B' was also detected.

Cohen, M.; Harvey, P. M.; Schwartz, R. D.

1985-01-01

84

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

85

Development of multi-object spectroscopy unit for simultaneous-color wide-field infrared multi-object spectrograph  

NASA Astrophysics Data System (ADS)

SWIMS (Simultaneous-color Wide-field Infrared Multi-object Spectrograph) has a multi-object spectroscopic function including IFU in addition to the imaging capability. The mechanism in order to achieve this function is Multi-Object Spectroscopy Unit. This is the function that can derive spectra of simultaneous 20-30 objects over range from 0.9 to 2.5?mm. To set or exchange a slit mask on telescope focal plane, MOSU consists of the slit-mask dewar (carrousel), focal plane dewar, and robotic arm called mask catcher. There are many structural and mechanical features in MOSU to achieve its performance in cooling system, positional repeatability of slit mask and so on. We present here its unique components and its specifications and performance.

Takahashi, Hidenori; Konishi, Masahiro; Motohara, Kentaro; Kato, Natsuko M.; Tateuchi, Ken; Kitagawa, Yurato; Todo, Soya

2014-08-01

86

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

87

Infrared Telescope Facility's Spectrograph Observations of Human-Made Space Objects  

NASA Technical Reports Server (NTRS)

Presented here are the results of the Infrared Telescope Facility (IRTF) spectral observations of human-made space objects taken from 2006 to 2008. The data collected using the SpeX infrared spectrograph cover the wavelength range 0.7-2.5 micrometers. Overall, data were collected on 20 different orbiting objects at or near the geosynchronous (GEO) regime. Four of the objects were controlled spacecraft, seven were non-controlled spacecraft, five were rocket bodies, and the final four were cataloged as debris pieces. The remotely collected data are compared to the laboratory-collected reflectance data on typical spacecraft materials, thereby general materials are identified but not specific types. These results highlight the usefulness of observations in the infrared by focusing on features from hydrocarbons, silicon, and thermal emission. The spacecraft, both the controlled and non-controlled, show distinct features due to the presence of solar panels, whereas the rocket bodies do not. Signature variations between rocket bodies, due to the presence of various metals and paints on their surfaces, show a clear distinction from those objects with solar panels, demonstrating that one can distinguish most spacecraft from rocket bodies through infrared spectrum analysis. Finally, the debris pieces tend to show featureless, dark spectra. These results show that the laboratory data in its current state give excellent indications as to the nature of the surface materials on the objects. Further telescopic data collection and model updates to include noise, surface roughness, and material degradation are necessary to make better assessments of orbital object material types. However, based on the current state of the comparison between the observations and the laboratory data, infrared spectroscopic data are adequate to classify objects in GEO as spacecraft, rocket bodies, or debris.

Abercromby, K.; Buckalew, B.; Abell, P.; Cowardin, H.

2015-01-01

88

Optically faint radio sources: reborn AGN?  

NASA Astrophysics Data System (ADS)

We present our discovery of several relatively strong radio sources in the field-of-view of SDSS galaxy clusters that have no optical counterparts down to the magnitude limits of the SDSS. The optically faint radio sources appear as double-lobed or core-jet objects in the FIRST radio images and have projected angular sizes ranging from 0.5 to 1.0 arcmin. We followed-up these sources with near-infrared imaging using the wide-field imager HAWK-I on the VLT. We detected Ks-band emitting regions, about 1.5 arcsec in size and coincident with the centers of the radio structures, in all sources, with magnitudes in the range 17-20 mag. We used spectral modelling to characterize the sample sources. In general, the radio properties are similar to those observed in 3CRR sources but the optical-radio slopes are consistent with those of moderate to high redshift (z < 4) gigahertz-peaked spectrum sources. Our results suggest that these unusual objects are galaxies whose black hole has been recently re-ignited but that retain large-scale radio structures, which are signatures of previous AGN activity.

Filho, M. E.; Brinchmann, J.; Lobo, C.; Antón, S.

2011-12-01

89

Research and development of infrared object detection system based on FPGA  

NASA Astrophysics Data System (ADS)

Infrared object detection is an important technique of digital image processing. It is widely used in automatic navigation, intelligent video surveillance systems, traffic detection, medical image processing etc. Infrared object detection system requires large storage and high speed processing technology. The current development trend is the system which can be achieved by hardware in real-time with fewer operations and higher performance. As a main large-scale programmable specific integrated circuit, field programmable gate array (FPGA) can meet all the requirements of high speed image processing, with the characteristics of simple algorithm realization, easy programming, good portability and inheritability. So it could get better result by using FPGA to infrared object detection system. According to the requirements, the infrared object detection system is designed on FPGA. By analyzing some of the main algorithms of object detection, two new object detection algorithms called integral compare algorithm (ICA) and gradual approach centroid algorithm (GACA) are presented. The system design applying FPGA in hardware can implement high speed processing technology, which brings the advantage of both performance and flexibility. ICA is a new type of denoising algorithm with advantage of lower computation complexity and less execution time. What is more important is that this algorithm can be implemented in FPGA expediently. Base on image preprocessing of ICA, GACA brings high positioning precision with advantage of insensitivity to the initial value and fewer times of convergence iteration. The experiments indicate that the infrared object detection system can implement high speed infrared object detecting in real-time, with high antijamming ability and high precision. The progress of Verilog-HDL and its architecture are introduced in this paper. Considering the engineering application, this paper gives the particular design idea and the flow of this method's realization in FPGA device. And we also discuss the problems on how to describe the hardware system in Verilog-HDL. Based on the hardware architecture of infrared object detection system, the component units of the system are discussed in detail, such as image data acquisition unit, data pre-processing unit and logical control unit etc. The design of the FPGA function and its implementation are carried on Verilog-HDL with TOP-DOWN method. The ending is the prospect of the project.

Zhao, Jianhui; He, Jianwei; Wang, Pengpeng; Li, Fan

2009-07-01

90

Constraining near-Earth object albedos using near-infrared spectroscopy  

Microsoft Academic Search

Low-albedo near-Earth objects (NEOs) are warm enough to emit detectable thermal flux at 2.5 ?m when near perihelion. Thermal radiation can account for 33% or more of the total flux for an object with an albedo ?0.04 at 1.0 AU. This is measurable using near-infrared spectroscopic instruments enabling albedos to be constrained for a larger sample of NEOs.

A. S. Rivkin; R. P. Binzel; S. J. Bus

2005-01-01

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

Polarization state imaging in long-wave infrared for object detection  

NASA Astrophysics Data System (ADS)

The article discusses the use of modern imaging polarimetry from the visible range of the spectrum to the far infrared. The paper presents the analyzes the potential for imaging polarimetry in the far infrared for remote sensing applications. In article a description of measurement stand is presented for examination of polarization state in LWIR. The stand consists of: infrared detector array with electronic circuitry, polarizer plate and software enabling detection method. The article also describes first results of measurements in presented test bed. Based on these measurements it was possible to calculate some of the Stokes parameters of radiation from the scene. The analysis of the measurement results show that the measurement of polarization state can be used to detect certain types of objects. Measuring the degree of polarization may allow for the detection of objects on an infrared image, which are not detectable by other techniques, and in other spectral ranges. In order to at least partially characterize the polarization state of the scene it is required to measure radiation intensity in different configurations of the polarizing filter. Due to additional filtering elements in optical path of the camera, the NETD parameter of the camera with polarizer in proposed measurement stand was equal to about 240mK. In order to visualize the polarization characteristics of objects in the infrared image, a method of imaging measurement results imposing them on the thermal image. Imaging of measurement results of radiation polarization is made by adding color and saturation to black and white thermal image where brightness corresponds to the intensity of infrared radiation.

Bieszczad, Grzegorz; Gogler, S?awomir; Krupi?ski, Micha?

2013-10-01

93

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

94

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

95

Circumstellar Environments of Luminous Infrared Stellar Objects in the Magellanic Clouds  

NASA Technical Reports Server (NTRS)

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

Azari, Abigail; Sahai, Raghvendra

2011-01-01

96

Centaurs and Scattered Disk Objects in the Thermal Infrared: Analysis of WISE/NEOWISE Observations  

NASA Astrophysics Data System (ADS)

The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and Scattered Disk Objects in the thermal infrared, including discoveries of 15 previously unknown objects. At this writing, this is the largest published collection of thermal infrared measurements of Centaur and SDOs. We present analyses of these observations to estimate sizes and mean optical albedos derived from photometry of the WISE images taken simultaneously at wavelengths of 3.4, 4.6, 12, and 22 microns. We find mean visual-wavelength geometric albedos of 0.08, +/- 0.04 standard deviations, 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, and there appears to be no trend of beaming with heliocentric distance. Raw cumulative size distributions for objects with diameters > 20 km yield size-frequency distribution power law indices ~ -1.7 +/- 0.3. The data also reveal a relation between albedo and color at the 3-sigma level, with those objects with visual-wavelength B-R colors < 1.4 magnitudes having significantly lower albedos than those with B-R colors exceeding 1.4 magnitudes. No significant relation between diameter and albedos is found. We will also discuss the implications of these survey results concerning the related comet and TNO populations.

Bauer, James M.; Grav, T.; Mainzer, A. K.; Masiero, J. R.; Blauvelt, E.; Stevenson, R.; Kramer, E.; Fernandez, Y. R.; Lisse, C. M.; Cutri, R. M.; Weissman, P. R.; Dailey, J. W.; Masci, F. J.; Walker, R.; Waszczak, A.; Nugent, C. R.; Meech, K. J.; Lucas, A.; Pearman, G.; Wilkins, A.; Watkins, J.; Kulkarni, S.; Wright, E. L.; WISE Team; PTF Team

2013-10-01

97

Time-resolved infrared spectrophotometric observations of high area to mass ratio (HAMR) objects in GEO  

NASA Astrophysics Data System (ADS)

Optical surveys have identified a class of high area-to-mass ratio (HAMR) objects in the vicinity of the Geostationary Earth Orbit (GEO) ring [1]. The exact origin and nature of these objects are not well known, although their proximity to the GEO ring poses a hazard to active GEO satellites. Due to their high area-to-mass ratios, solar radiation pressure perturbs their orbits in ways that makes it difficult to predict their orbital trajectories over periods of time exceeding a week. To better understand these objects and their origins, observations that allow us to derive physical characteristics are required in order to improve the non-conservative force modeling for orbit determination and prediction. Information on their temperatures, areas, emissivities, and albedos may be obtained from thermal infrared, mid-wave infrared (MWIR), and visible measurements. Spectral features may help to identify the composition of the material, and thus possible origins for these objects. We have collected observational data on various HAMR objects from the AMOS observatory 3.6 m AEOS telescope. The thermal-IR spectra of these low-earth orbit objects acquired by the Broadband Array Spectrograph System (BASS) span wavelengths 3-13 ?m and constitute a unique data set, providing a means of measuring, as a function of time, object fluxes. These, in turn, allow temperatures and emissivity-area products to be calculated. In some instances we have also collected simultaneous filtered visible photometric data on the observed objects. The multi-wavelength observations of the objects provide possible clues as to the nature of the observed objects. We describe briefly the nature and status of the instrumental programs used to acquire the data, our data of record, our data analysis techniques, and our current results, as well as future plans.

Skinner, Mark A.; Russell, Ray W.; Rudy, Richard J.; Gutierrez, David J.; Kim, Daryl L.; Crawford, Kirk; Gregory, Steve; Kelecy, Tom

2011-12-01

98

Further analysis of infrared spectrophotometric observations of high area to mass ratio (HAMR) objects in GEO  

NASA Astrophysics Data System (ADS)

Optical surveys have identified a class of high area-to-mass ratio (HAMR) objects in the vicinity of the Geostationary Earth Orbit (GEO) ring?. The exact origin and nature of these objects are not well known, although their proximity to the GEO belt poses a hazard to active GEO satellites. The prevalent conjecture is that many of these objects may be thermal materials shed from derelict spacecraft in 'graveyard' orbits above the GEO ring. Due to their high area-to-mass ratios and unknown attitude dynamics and material characteristics, solar radiation pressure (SRP) perturbs their orbits in ways that makes it difficult to predict their orbital trajectories over periods of time exceeding a week or less. To better understand and track these objects and infer their origins, we have made observations that allow us to determine physical characteristics that will improve the non-conservative force modeling used for orbit determination (OD) and prediction. Information on their temperatures, areas, emissivities, and albedos may be obtained from thermal infrared and visible measurements. Simultaneous observations in the thermal infrared and visible wavelengths may allow disentangling of projected area, albedo, and object emissivity. Further analysis and modeling of observational data on certain of the HAMR objects collected at the AMOS observatory 3.6 m AEOS telescope are presented. The thermal-IR spectra of these geosynchronous orbit objects acquired by the Broadband Array Spectrograph System (BASS) span wavelengths 3 to 13 ?m and constitute a unique data set, providing a means of measuring object fluxes in the infrared and visible wavelengths. These, in turn, allow temperatures and emissivity-area products to be calculated, and in some cases provide information on rotation rates. We compare our observational results with the outputs of simple models, in terms of visible and infrared flux and orbital characteristics. The resulting temperatures and rotation rates are used in SRP acceleration models to demonstrate improvements in OD and prediction performance relative to models which assume default ambient temperature and static attitude dynamics. Additionally, we have the capability and plans to measure material properties with the same instrument in the lab as used at the telescope to facilitate direct comparisons.

Skinner, Mark A.; Russell, Ray W.; Kelecy, Tom; Gregory, Steve; Rudy, Richard J.; Gutierrez, David J.; Kim, Daryl L.; Crawford, Kirk

2012-11-01

99

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

100

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

101

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

102

Young Stars in the Camelopardalis Dust and Molecular Clouds. II. Infrared Objects  

E-print Network

Using infrared photometric data extracted from the 2MASS, IRAS and MSX databases, 142 suspected young stellar objects (YSOs) are selected from about 2 million stars in the Camelopardalis segment of the Milky Way limited by Galactic longitude 132-158 deg, latitude pm 12 deg. According to radial velocities of the associated CO clouds, the objects are attributed to three molecular and dust cloud layers at 150--300 pc, 900 pc and 2.2 kpc distances from the Sun. These objects concentrate into dust and molecular clouds and exhibit extremely large reddenings (A_V up to 25 mag) which can be caused by the dust in foreground clouds and circumstellar envelopes or disks. In the J-H vs. H-K diagram these objects lie above the intrinsic line of T Tauri variables, roughly along the black-body line. Among the identified objects, some already known YSOs are present, including the well investigated massive object GL 490. The spectral energy distributions between 700 nm and 100 mum suggest that the objects may be YSOs of classes I, II and III. However, we do not exclude the possibility that a small fraction of the objects, especially those without IRAS and MSX photometry, may be unrecognized heavily reddened OB-stars, late-type AGB stars or even galaxies.

V. Straizys; V. Laugalys

2008-03-17

103

Infrared Spectroscopy and Analysis of Brown Dwarf and Planetary Mass Objects in the Orion Nebula Cluster  

E-print Network

We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in the Orion Nebula Cluster. The long slit data were observed in the H- & 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 H-R 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 t...

Weights, D J; Roche, P F; Pinfield, D J; Riddick, F

2008-01-01

104

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

105

Centaurs and Scattered Disk Objects in the Thermal Infrared: Analysis of WISE/NEOWISE Observations  

NASA Astrophysics Data System (ADS)

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 ~-1.7 ± 0.3. The data also reveal a relation between albedo and color at the 3? level. No significant relation between diameter and albedos is found.

Bauer, James M.; Grav, Tommy; Blauvelt, Erin; Mainzer, A. K.; Masiero, Joseph R.; Stevenson, Rachel; Kramer, Emily; Fernández, Yan R.; Lisse, C. M.; Cutri, Roc M.; Weissman, Paul R.; Dailey, John W.; Masci, Frank J.; Walker, Russel; Waszczak, Adam; Nugent, Carrie R.; Meech, Karen J.; Lucas, Andrew; Pearman, George; Wilkins, Ashlee; Watkins, Jessica; Kulkarni, Shrinivas; Wright, Edward L.; WISE Team; PTF Team

2013-08-01

106

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

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

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

NASA Astrophysics Data System (ADS)

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

Kruger, Andrew James

109

Infrared Spectroscopy and Analysis of Brown Dwarf and Planetary Mass Objects in the Orion Nebula Cluster  

E-print Network

We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in the Orion Nebula Cluster. The long slit data were observed in the H- & 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 H-R 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 (0.075 Msun). 10 sources potentially have masses below the deuterium burning limit (0.012 Msun). We use a Monte Carlo approach to model the observed luminosity function with a variety of cluster age and mass distributions. The lowest chi^2 values are produced by an age distribution centred at 1 Myr, with a mass function that declines at sub-stellar masses according to an M^alpha power law in the range alpha=0.3 to 0.6. We find that truncating the mass function at 0.012 Msun 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.

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

2008-10-20

110

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

111

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

112

Comparison of broadband and hyperspectral thermal infrared imaging of buried threat objects  

NASA Astrophysics Data System (ADS)

Previous research by many groups has shown that broad-band thermal infrared (TIR) imagers can detect buried explosive threat devices, such as unexploded ordnance (UXO), landmines and improvised explosive devices (IEDs). Broad-band detection measures the apparent temperature - an average over the wave band of the product of the true soil surface temperature and the emissivity. Broad-band detection suffers from inconsistent performance (low signal, high clutter rates), due in part to diurnal variations, environmental and meteorological conditions, and soil surface effects. It has been suggested that hyperspectral TIR imaging might have improved performance since it can, in principle, allow extraction of the wavelength-dependent emissivity and the true soil surface temperature. This would allow the surface disturbance effects to be separated from the soil column (bulk) effects. A significant, and as yet unanswered, question is whether hyperspectral TIR images provide better detection capability (higher probability of detection and/or lower false alarm rate) than do broad-band thermal images. TIR hyperspectral image data of threat objects, buried and surface-laid in bare soil, were obtained in arid, desert-like conditions over full diurnal cycles for several days. Regions of interest containing threat objects and backgrounds were extracted throughout the time period. Simulated broad-band images were derived from the hyperspectral images. The diurnal variation of the images was studied. Hyperspectral was found to provide some advantage over broad-band imaging in detection of buried threat objects for the limited data set studied.

McFee, John E.; Achal, Steve B.; Diaz, Alejandra U.; Faust, Anthony A.

2013-06-01

113

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

114

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

115

IR Colors and Sizes of Faint Galaxies  

E-print Network

We present J and Ks band galaxy counts down to J=24 and Ks=22.5 obtained with the new infrared imager/spectrometer, SOFI, at the ESO New Technology Telescope. The co-addition of short, dithered, images led to a total exposure time of 256 and 624 minutes respectively, over an area of $\\sim20$ arcmin$^2$ centered on the NTT Deep Field. The total number of sources with S/N$>5$ is 1569 in the J sample and 1025 in the Ks-selected sample. These are the largest samples currently available at these depths. A d$logN$/d$m$ relation with slope of $\\sim0.36$ in J and $\\sim0.38$ in Ks is found with no evident sign of a decline at the magnitude limit. The observed surface density of ``small'' sources is much lower than ``large'' ones at bright magnitudes and rises more steeply than the large sources to fainter magnitudes. Fainter than $J\\sim22.5$ and Ks$\\sim21.5$, small sources dominate the number counts. Galaxies get redder in J-K down to J$\\sim20$ and Ks$\\sim19$. At fainter magnitudes, the median color becomes bluer with an accompanying increase in the compactness of the galaxies. We show that the blue, small sources which dominate the faint IR counts are not compatible with a high redshift ($z>1$) population. On the contrary, the observed color and compactness trends, together with the absence of a turnover at faint magnitudes and the dominance of small sources, can be naturally explained by an increasing contribution of sub-$L^*$ galaxies when going to fainter apparent magnitudes. Such evidence strongly supports the existence of a steeply rising ($\\alpha\\ll-1$) faint end of the local infrared luminosity function of galaxies - at least for luminosities $L<0.01L^*$.

P. Saracco; S. D'Odorico; A. Moorwood; A. Buzzoni; J. - G. Cuby; C. Lidman

1999-08-02

116

Infrared near-Earth-object survey modeling for observatories interior to the Earth's orbit  

NASA Astrophysics Data System (ADS)

The search for and dynamical characterization of the near-Earth population of objects (NEOs) has been a busy topic for surveys for many years. Most of the work thus far has been from ground-based optical surveys such as the Catalina Sky Survey and LINEAR. These surveys have essentially reached a complete inventory of objects down to 1 km diameter and have shown that the known objects do not pose any significant impact threat. Smaller objects are correspondingly smaller threats but there are more of them and fewer of them have so far been discovered. The next generation of surveys is looking to extend their reach down to much smaller sizes. From an impact risk perspective, those objects as small as 30--40 m are still of interest (similar in size to the Tunguska bolide). Smaller objects than this are largely of interest from a space resource or in-situ analysis efforts. A recent mission concept promoted by the B612 Foundation and Ball Aerospace calls for an infrared survey telescope in a Venus-like orbit, known as the Sentinel Mission. This wide-field facility has been designed to complete the inventory down to a 140 m diameter while also providing substantial constraints on the NEO population down to a Tunguska-sized object. I have been working to develop a suite of tools to provide survey modeling for this class of survey telescope. The purpose of the tool is to uncover hidden complexities that govern mission design and operation while also working to quantitatively understand the orbit quality provided on its catalog of objects without additional followup assets. The baseline mission design calls for a 6.5 year survey lifetime. This survey model is a statistically based tool for establishing completeness as a function of object size and survey duration. Effects modeled include the ability to adjust the field-of-regard (includes all pointing restrictions), field-of-view, focal plane array fill factor, and the observatory orbit. Consequences tracked include time-tagged detection times from which orbit quality can be derived and efficiency by dynamical class. The dominant noise term in the simulations comes from the noise in the background flux caused by thermal emission from zodiacal dust. The model used is sufficient for the study of reasonably low-inclination spacecraft orbits such as are being considered. Results to date are based on the 2002 Bottke NEA orbit-distribution model. The system can work with any orbit-distribution model and with any size-frequency distribution. This tool also serves to quantify the amount of data that will also be collected on main-belt objects by simply testing against the known catalog of bodies. The orbit quality work clearly shows the benefit of a self-followup survey such as Sentinel. Most objects discovered will be seen in multiple observing epochs and the resulting orbits will preclude losing track of them for decades to come (or longer). All of the ephemeris calculations, including investigation of orbit determination quality, are done with the OpenOrb software package. The presentation for this meeting will be based on results of modeling the Sentinel Mission and other similar variants. The focus will be on evaluating the survey completion for different dynamical classes as well as for different sized objects. Within the fidelity of such statistically-based models, the planned Sentinel observatory is well capable of a huge step forward in the efforts to build a complete catalog of all objects that could pose future harm to planet Earth.

Buie, M.

2014-07-01

117

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

118

The metrology system for the multi-object optical and near-infrared spectrograph MOONS  

NASA Astrophysics Data System (ADS)

The Multi-Object Optical and Near-infrared Spectrograph (MOONS) is a new fiber-fed spectrograph for the VLT. MOONS will exploit the full 500 square arcmin field of view offered by the Nasmyth focus of VLT and will be equipped with two dual-arm spectrographs covering the wavelength range 0.8 µm-1.8 ?m, with a possible extension down to 0.5 ?m. Each double-arm spectrograph will produce spectra for 250 targets simultaneously, each with its own dedicated sky fiber for optimal sky subtraction. The system will have both a medium resolution (R 3000 - 5000) mode and a high resolution (R 20000) mode to allow detailed dynamical and chemical studies. To ensure the accurate positioning of the 500 fiber pairs over the focal plane that has 880 mm in diameter, a metrology system has been designed to provide position measurements within 7.5 ?m considering that the final positioning accuracy of each fiber with respect to the target object must be less than 15 ?m. The metrology system is composed by a circular array of 12 cameras located at VLT's de-rotator ring around the Nasmyth focus. The paper presents the design of the metrology system and discusses the proposed methodology to align multiple the views of the focal plane array.

Torres-Torriti, Miguel; Vanzi, Leonardo; Dünner, Rolando; Belmar, Francisco; Dauvin, Louise; Chen, Tzu-Chiang; Cirasuolo, Michele; Taylor, William; Schnetler, Hermine; Montgomery, David; Rees, Philip; Cabral, Alexandre

2014-07-01

119

An Infrared Multi-Object Spectrograph (IRMS) with adaptive optics for TMT: the science case  

NASA Astrophysics Data System (ADS)

It has been recognized that a Near-Infrared Multi-object Spectrograph (IRMS) as one of the first light instrument on the Thirty Meter Telescope (TMT) would significantly increase the scientific capability of the observatory. The IRMS is planned to be a clone of the MOSFIRE instrument on the Keck telescope. As a result, we use the already available MOSFIRE design and expertise, significantly reducing the total cost and its development time. The IRMS will be a quasi diffraction limited multi-slit spectrograph with moderate resolution (R~4000), fed by Narrow-Field Infrared Adaptive Optics System (NFIRAOS). It images over the 2 arcmin diameter field of view of the NFIRAOS. There are a number of exceedingly important scientific questions, waiting to be addressed by the TMT/IRMS combination. Given its relatively small field of view, it is less affected by the sky background, which is a limiting factor in ground-based observations at near-IR wavelengths. The IRMS is the ideal instrument for studying spectroscopic properties of galaxies at the re-ionization epoch (z > 7), where the Lyman alpha line shifts to the near-ir wavelenghths. It can be used to measure rotation curves of spiral and velocity dispersion of elliptical galaxies at z~2-3 and hence, their spectroscopic mass. It can be used to search for population III stars via their spectroscopic signature and to perform measurement of spectroscopic lines at high redshifts, diagnostic of metallicity. Finally, IRMS allows measurement of the blue shifts in the rest-frame MgII line for high redshift galaxies, used to study the winds, leading to the feedback mechanism, responsible for quenching star formation activity in galaxies.

Mobasher, Bahram; Crampton, David; Simard, Luc

2010-07-01

120

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

SciTech Connect

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

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

2010-06-01

121

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

122

Subsystem Imaging Performance and Modeling of the Infrared Multi-Object Spectrograph  

NASA Technical Reports Server (NTRS)

The Infrared Multi-Object Spectrograph (IRMOS) is a facility instrument for the Kitt Peak National Observatory Mayall Telescope (3.8 meter). IRMOS is a near-IR (0.8 - 2.5 micron) spectrograph with low to mid resolution (R=lambda/delta, lambda = 300 - 3800). The IRMOS spectrograph produces simultaneous spectra of - 100 objects in its 2.8 x 2.0 arc-min field of view using a commercial MEMS multi-mirror array device (MMA). The IRMOS optical design consists of two imaging systems, or "stages." The focal reducer, stage one, images the focal plane of the telescope onto the MMA. The spectrograph, stage two, images the MMA onto the detector. We describe the breadboard alignment method and imaging and scattered light performance for both the focal reducer and spectrograph. This testing provides verification of the optomechanical alignment method, and a measurement of the contribution of scattered light in the system due to mirror small scale surface error. After the stage I and 2 optics are integrated with the instrument, our test results will make it possible to distinguish between scattered light from the mirrors and the MMA. Image testing will be done at four wavelengths in the visible and near-IR. A mercury-argon pencil lamp will provide spectral lines at 546.1 and 1012 nm, and a blackbody radiation source lines at 1600 and 2200 nm. A CCD camera will be used as a detector for the visible wavelengths, and an IR photodiode will be used for the IR wavelengths. We compare our data with a theoretical analysis using a commercial software package. Mirror surface error is modeled by treating each surface as a superposition of various gratings (e.g., diamond turning tool marks, features due to the impurities of Al 6061, and periodic mid-frequency errors due to drift during machining).

Connelly, Joseph A.; Tveekrem, June L.; Ohl, Raymond G.; Mink, Ronald; Chambers, V. John; Mentzell, J. Eric; Greenhouse, Matthew A.; MacKenty, John W.; Krebs, Carolyn (Technical Monitor)

2002-01-01

123

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

124

MOONS: a Multi-Object Optical and Near-infrared Spectrograph for the VLT  

E-print Network

MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A study. The baseline design consists of 1000 fibers deployable over a field of view of 500 square arcmin, the largest patrol field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8um-1.8um and two resolution modes: medium resolution and high resolution. In the medium resolution mode (R=4,000-6,000) the entire wavelength range 0.8um-1.8um is observed simultaneously, while the high resolution mode covers simultaneously three selected spectral regions: one around the CaII triplet (at R=8,000) to measure radial velocities, and two regions at R=20,000 one in the J-band and one in the H-band, for detailed measurements of chemical abundances. The grasp of the 8.2m Very Large Telescope (VLT) combined with the large multiplex and wavelength coverage of MOONS - extending into the near-IR - will provide the observational power necessary to...

Cirasuolo, M; Bender, R; Bonifacio, P; Evans, C; Kaper, L; Oliva, E; Vanzi, L; Abreu, M; Atad-Ettedgui, E; Babusiaux, C; Bauer, F; Best, P; Bezawada, N; Bryson, I; Cabral, A; Caputi, K; Centrone, M; Chemla, F; Cimatti, A; Cioni, M-R; Clementini, G; Coelho, J; Daddi, E; Dunlop, J; Feltzing, S; Ferguson, A; Flores, H; Fontana, A; Fynbo, J; Garilli, B; Glauser, A; Guinouard, I; Hammer, F; Hastings, P; Hess, A; Ivison, R; Jagourel, P; Jarvis, M; Kauffman, G; Lawrence, A; Lee, D; Licausi, G; Lilly, S; Lorenzetti, D; Maiolino, R; Mannucci, F; McLure, R; Minniti, D; Montgomery, D; Muschielok, B; Nandra, K; Navarro, R; Norberg, P; Origlia, L; Padilla, N; Peacock, J; Pedicini, F; Pentericci, L; Pragt, J; Puech, M; Randich, S; Renzini, A; Ryde, N; Rodrigues, M; Royer, F; Saglia, R; Sanchez, A; Schnetler, H; Sobral, D; Speziali, R; Todd, S; Tolstoy, E; Torres, M; Venema, L; Vitali, F; Wegner, M; Wells, M; Wild, V; Wright, G

2012-01-01

125

a Faint and Lonely Brown Dwarf in the Solar Vicinity  

NASA Astrophysics Data System (ADS)

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

1997-04-01

126

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

E-print Network

Near-infrared H2 and Continuum Survey of Extended Green Objects. II. Complete Census for the Northern Galactic Plane Hsu-Tai Lee1 htlee@illinois.edu Institute of Astronomy and Astrophysics, Academia of Kent, Canterbury, CT2 7NH, U.K. Jennifer Karr Institute of Astronomy and Astrophysics, Academia Sinica

Froebrich, Dirk

127

MID-INFRARED SIZE SURVEY OF YOUNG STELLAR OBJECTS: DESCRIPTION OF KECK SEGMENT-TILTING EXPERIMENT AND BASIC RESULTS  

SciTech Connect

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 ({lambda} = 10.7 {mu}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.; Tannirkulam, A. [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Tuthill, P. G.; Ireland, M. [University of Sydney, NSW 2006 (Australia); Cohen, R. [W. M. Keck Observatory, Kamuela, HI 96743 (United States); Perrin, M. D. [University of California at Los Angeles, CA 90095 (United States)

2009-07-20

128

Near-infrared H2 emission from Herbig-Haro objects. I - A survey of low excitation objects  

NASA Astrophysics Data System (ADS)

A survey for H2 1-0 S(1) emission in 16 Herbig-Haro (HH) objects and three exciting stars for HH objects is reported. Eleven HH objects which show low-excitation optical spectra exhibit H2 emission. One object (HH 43) is more than twice as bright as any previously reported HH object. In addition, spectra in the range 1.6-2.55 microns are reported for HH 43 and HH 120, and a 2.0-2.55 micron spectrum is presented for HH 26. The spectra yield estimates of the H2 density and temperature ranges in these objects. The role of ultraviolet H2 emission-line fluorescence in HH 43 with respect to cascading among excited vibrational states of the ground electronic state is discussed. Models which may account for the combined ultraviolet, optical, and near-IR spectra of HHs are briefly analyzed.

Schwartz, Richard D.; Cohen, Martin; Williams, Peredur M.

1987-11-01

129

Near-infrared H2 emission from Herbig-Haro objects. I - A survey of low excitation objects  

NASA Technical Reports Server (NTRS)

A survey for H2 1-0 S(1) emission in 16 Herbig-Haro (HH) objects and three exciting stars for HH objects is reported. Eleven HH objects which show low-excitation optical spectra exhibit H2 emission. One object (HH 43) is more than twice as bright as any previously reported HH object. In addition, spectra in the range 1.6-2.55 microns are reported for HH 43 and HH 120, and a 2.0-2.55 micron spectrum is presented for HH 26. The spectra yield estimates of the H2 density and temperature ranges in these objects. The role of ultraviolet H2 emission-line fluorescence in HH 43 with respect to cascading among excited vibrational states of the ground electronic state is discussed. Models which may account for the combined ultraviolet, optical, and near-IR spectra of HHs are briefly analyzed.

Schwartz, Richard D.; Cohen, Martin; Williams, Peredur M.

1987-01-01

130

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

131

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

132

Mid-infrared interferometry of the massive young stellar object NGC 3603 - IRS 9A  

NASA Astrophysics Data System (ADS)

Context. Very few massive young stellar objects (MYSO) have been studied in the infrared at high angular resolution due to their rarity and large associated extinction. We present observations and models for one of these MYSO candidates, NGC 3603 IRS 9A. Aims: Our goal is to investigate with infrared interferometry the structure of IRS 9A on scales as small as 200 AU, exploiting the fact that a cluster of O and B stars has blown away much of the obscuring foreground dust and gas. Methods: Observations in the N-band were carried out with the MIDI beam combiner attached to the VLTI, providing spatial information on scales of about 25-95 milli-arcsec (mas). Additional interferometric observations which probe the structure of IRS 9A on larger scales were performed with an aperture mask installed in the T-ReCS instrument of Gemini South. The spectral energy distribution (SED) is constrained by the MIDI N-band spectrum and by data from the Spitzer Space Telescope. Our efforts to model the structure and SED of IRS 9A range from simple geometrical models of the brightness distribution to one- and two-dimensional radiative transfer computations. Results: The target is resolved by T-ReCS, with an equivalent (elliptical) Gaussian width of 330 mas by 280 mas (2300 AU by 2000 AU). Despite this fact, a warm compact unresolved component was detected by MIDI which is possibly associated with the inner regions of a flattened dust distribution. Based on our interferometric data, no sign of multiplicity was found on scales between about 200 AU and 700 AU projected separation. A geometric model consisting of a warm (1000 K) ring (400 AU diameter) and a cool (140 K) large envelope provides a good fit to the data. No single model fitting all visibility and photometric data could be found, with disk models performing better than spherical models. Conclusions: While the data are clearly inconsistent with a spherical dust distribution they are insufficient to prove the existence of a disk but rather hint at a more complex dust distribution. Based in part on observations collected at the European Southern Observatory, Chile (Prop. No. 074.C-0062) and the Gemini South Observatory, Chile.

Vehoff, S.; Hummel, C. A.; Monnier, J. D.; Tuthill, P.; Nürnberger, D. E. A.; Siebenmorgen, R.; Chesneau, O.; Duschl, W. J.

2010-09-01

133

Near-infrared integral field spectroscopy of massive young stellar objects  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

134

Spectrum from Faint Galaxy IRAS F00183-7111  

NASA Technical Reports Server (NTRS)

NASA's Spitzer Space Telescope has detected the building blocks of life in the distant universe, albeit in a violent milieu. Training its powerful infrared eye on a faint object located at a distance of 3.2 billion light-years, Spitzer has observed the presence of water and organic molecules in the galaxy IRAS F00183-7111. With an active galactic nucleus, this is one of the most luminous galaxies in the universe, rivaling the energy output of a quasar. Because it is heavily obscured by dust (see visible-light image in the inset), most of its luminosity is radiated at infrared wavelengths.

The infrared spectrograph instrument onboard Spitzer breaks light into its constituent colors, much as a prism does for visible light. The image shows a low-resolution spectrum of the galaxy obtained by the spectrograph at wavelengths between 4 and 20 microns. Spectra are graphical representations of a celestial object's unique blend of light. Characteristic patterns, or fingerprints, within the spectra allow astronomers to identify the object's chemical composition and to determine such physical properties as temperature and density.

The broad depression in the center of the spectrum denotes the presence of silicates (chemically similar to beach sand) in the galaxy. An emission peak within the bottom of the trough is the chemical signature for molecular hydrogen. The hydrocarbons (orange) are organic molecules comprised of carbon and hydrogen, two of the most common elements on Earth. Since it has taken more than three billion years for the light from the galaxy to reach Earth, it is intriguing to note the presence of organics in a distant galaxy at a time when life is thought to have started forming on our home planet.

Additional features in the spectrum reveal the presence of water ice (blue), carbon dioxide ice (green) and carbon monoxide (purple) in both gas and solid forms. The magenta peak corresponds to singly ionized neon gas, a spectral line often used by astronomers as a diagnostic of star formation rates in distant galaxies.

The Spitzer spectrum is the result of only 14 minutes of integration time, highlighting the power of the infrared spectrograph to unlock the secrets of distant galaxies.

2003-01-01

135

Infrared studies of the Herbig-Haro object 1-2 region  

NASA Technical Reports Server (NTRS)

Far-infrared (50-100 micrometers) photometric mapping and near-infrared spectroscopic mapping of the Herbig-Haro 1-2 region are presented. Both lobes of the double-lobed far-infrared source in this region are found to be nearly coincident with recently discovered radio continuum sources. The dust temperature structure around each peak is not spherically symmetric, suggesting either that the far-infrared sources are centrally heated or that the dust column density is highly nonspherically symmetric. The results are consistent with a picture in which each far-infrared lobe contains a highly obscured young star surrounded by a highly nonspherically symmetric dust cloud. A complementary study by Strom et al. (1985) is pointed out.

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

1986-01-01

136

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

137

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

NASA Technical Reports Server (NTRS)

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

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

2015-01-01

138

Probing the envelopes of massive young stellar objects with diffraction limited mid-infrared imaging  

NASA Astrophysics Data System (ADS)

Context. Massive stars form whilst they are still embedded in dense envelopes. As a result, the roles of rotation, mass loss and accretion in massive star formation are not well understood. Aims: This study evaluates the source of the Q-band, ?c = 19.5 ?m, emission of massive young stellar objects (MYSOs). This allows us to determine the relative importance of rotation and outflow activity in shaping the circumstellar environments of MYSOs on 1000 AU scales. Methods: We obtained diffraction limited mid-infrared images of a sample of 20 MYSOs using the VLT/VISIR and Subaru/COMICS instruments. For these 8 m class telescopes and the sample selected, the diffraction limit, ~0.6'', corresponds to approximately 1000 AU. We compare the images and the spectral energy distributions (SEDs) observed to a 2D, axis-symmetric dust radiative transfer model that reproduces VLTI/MIDI observations of the MYSO W33A. We vary the inclination, mass infall rate, and outflow opening angle to simultaneously recreate the behaviour of the sample of MYSOs in the spatial and spectral domains. Results: The mid-IR emission of 70 percent of the MYSOs is spatially resolved. In the majority of cases, the spatial extent of their emission and their SEDs can be reproduced by the W33A model featuring an in-falling, rotating dusty envelope with outflow cavities. There is independent evidence that most of the sources which are not fit by the model are associated with ultracompact H ii regions and are thus more evolved. Conclusions: We find that, in general, the diverse ~20 ?m morphology of MYSOs can be attributed to warm dust in the walls of outflow cavities seen at different inclinations. This implies that the warm dust in the outflow cavity walls dominates the Q-band emission of MYSOs. In turn, this emphasises that outflows are an ubiquitous feature of massive star formation. This paper is based on data obtained using the ESO VLT at the Paranal Observatory with programme 083.C-0795 and the Subaru telescope, which is operated by the National Astronomical Observatory of Japan.Appendix A and Fig. 2 are available in electronic form at http://www.aanda.org

Wheelwright, H. E.; de Wit, W. J.; Oudmaijer, R. D.; Hoare, M. G.; Lumsden, S. L.; Fujiyoshi, T.; Close, J. L.

2012-04-01

139

Ultraviolet, visual, and infrared studies of galactic extreme emission line objects with very large IR-excess  

NASA Technical Reports Server (NTRS)

Some preliminary results of a study of extreme emission line objects (EELOs) are presented. These stars are selected from H alpha emission line stars having a strong IR excess. The study is based on multiwavelength photometric and spectroscopic observations. Special attention is paid to the detailed study of the correlation between spectroscopic and photometric variations, which indicate the activity of the star. The ultraviolet and infrared extinction characteristics of the circumstellar material are given special attention.

Dewinter, D.; Perez, M. R.; Hu, J. Y.; The, P. S.

1990-01-01

140

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

Microsoft Academic Search

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

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

2005-01-01

141

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

142

Detection of buried objects by fusing dual-band infrared images  

SciTech Connect

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

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

1993-11-01

143

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

Microsoft Academic Search

We report on the design and status of the FLAMINGOS-2 instrument - a 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 2048×2048-pixel HAWAII-2 0.9-2.4 mum detector array. A slit\\/decker wheel mechanism allows the selection of up to 9 multi-object

Stephen Eikenberry; Richard Elston; S. Nicholas Raines; Jeff Julian; Kevin Hanna; David Hon; Roger Julian; R. Bandyopadhyay; J. Greg Bennett; Aaron Bessoff; Matt Branch; Richard Corley; John-David Eriksen; Skip Frommeyer; Anthony Gonzalez; Michael Herlevich; Antonio Marin-Franch; Jose Marti; Charlie Murphey; David Rashkin; Craig Warner; Brian Leckie; W. Rusty Gardhouse; Murray Fletcher; Jennifer Dunn; Robert Wooff; Tim Hardy

2006-01-01

144

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

145

Visible and near-infrared spectroscopic investigation of near-Earth objects at ESO: first results  

Microsoft Academic Search

Near-Earth objects (NEOs) represent one of the most intriguing populations of Solar System bodies. These objects appear heterogeneous in all aspects of their physical properties, like shapes, sizes, spin rates, compositions etc. Moreover, as these objects represent also a real threat to the Earth, a good knowledge of their properties and composition is the necessary first step to evaluate mitigation

M. Lazzarin; S. Marchi; M. A. Barucci; M. Di Martino; C. Barbieri

2004-01-01

146

Near infrared photographic sky survey. 1: Catalog of red stellar objects  

NASA Technical Reports Server (NTRS)

Red stellar objects for which V-1 was greater than a value of about 2 (supm). 5 were extracted from photographs of 23 program fields. Tabular data for each field show the object name; the 1950 epoch right ascension, declination, galactic longitude, galactic latitude; radial distance from field venter in decimal degrees; color classes; and objects ordered by redness.

Craine, E. R.; Duerr, R. E.; Horner, V. M.; Imhoff, C. L.; Routsis, D. E.; Swihart, D. L.; Turnshek, D. A.

1979-01-01

147

Chandra Observations of Faint LMXB's  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

148

The Origin of the Infrared Emission in Radio Galaxies. III. Analysis of 3CRR Objects  

Microsoft Academic Search

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]lambda5007 emission line luminosity) and 24 mum luminosity. This

D. Dicken; C. Tadhunter; D. Axon; A. Robinson; R. Morganti; P. Kharb

2010-01-01

149

Supervised-PCA and SVM Classifiers for Object Detection in Infrared Images  

Microsoft Academic Search

We tackle the problem of detecting sources of combustion in high definition multispectral medium wavelength infrared (MWIR) (3-5 ?m) images. We present a novel approach to this problem consisting of processing the images block-wise using a new technique that we call supervised principal component analysis (SPCA) to get the components of these blocks. This outperforms state-of-the-art methods with a significant

Ricardo Santiago-mozos; José M. Leiva-murillo; Fernando Pérez-cruz; Antonio Artés-rodríguez

2003-01-01

150

Spectral observations for near-Earth objects including potential target 4660 Nereus : Results from Meudon remote observations at the NASA Infrared Telescope Facility (IRTF)  

Microsoft Academic Search

We present visible and near-infrared spectral measurements for the highly accessible spacecraft target 4660 Nereus and three additional near-Earth objects displaying diverse color characteristics. All near-infrared measurements were carried out during the first remote observing operations between the Observatoire de Paris at Meudon and Mauna Kea, Hawaii. From Meudon, we had fine pointing and guiding control of the NASA Infrared

Richard P. Binzel; Mirel Birlan; Schelte J. Bus; Alan W. Harris; Andrew S. Rivkin; Sonia Fornasier

2004-01-01

151

Searching for Optically Faint GEO Debris  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

152

Fainting  

MedlinePLUS

... KidsHealth in the Classroom What Other Parents Are Reading Measles: What to Know Vaccines: FAQs NBA Exercise ... the area is well-ventilated, wipe your child's face with a cool washcloth, and don't let ...

153

Fainting  

MedlinePLUS

... usually because changes in the nervous system and circulatory system cause a temporary drop in the amount of ... a lot of changes, including changes in the circulatory system. This leads to low blood pressure that may ...

154

Fainting  

MedlinePLUS

... pressure, and allergies (these drugs may cause a drop in blood pressure) Drug or alcohol use Hyperventilation Low blood sugar Seizures Sudden drop in blood pressure (such as from bleeding or being severely dehydrated ) ...

155

Faintness  

MedlinePLUS

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156

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

157

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

158

The High AV Quasar Survey: Reddened Quasi-Stellar Objects Selected from Optical/Near-Infrared Photometry—II  

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

159

Infrared Spectroscopy of Low Mass Objects in the Star-Forming Region L988  

NASA Astrophysics Data System (ADS)

Using JH spectra taken with FLAMINGOS on the KPNO 4m telescope we have classified 17 stellar objects in the open cluster L988 with spectral types between M1 and M8.5. These objects were placed on an H-R diagram by combining these spectral types with JHK photometry. Masses and ages for individual members were assigned by overlaying theoretical isochrones and a median age for the cluster was determined.

Steinhauer, Aaron J.; Jutzeler, E. C.; Lada, E.

2007-12-01

160

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.

161

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

162

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

163

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

164

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

165

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

166

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

167

Infrared spectra of transition objects and the composition and evolution of carbon dust  

NASA Technical Reports Server (NTRS)

We obtained IR (5-23 microns) spectra of five carbon-rich objects in transition from the asymptotic giant branch (AGB) to the planetary nebula stage of evolution. These spectra show a variety of IR emission features due to circumstellar materials. In particular, all sources show the 6.2 and '7.7' micron bands, commonly observed in PNs and ascribed to polycyclic aromatic hydrocarbon molecules (PAHs). Some transition nebulae also show a strong 6-9 micron plateau characteristic for larger PAH clusters (about 400 C-atoms). A new broad feature at about 8.8 microns is present in some sources. This feature is distinctly different from the 8.6-micron PAH feature. This 8.8-micron feature may be present in the spectra of C-rich giants as well, but is not evident in PN spectra. We suggest that large amorphous carbon grains are responsible for the 8.8-micron feature. The transition objects show large spectral variations from source to source. This contrasts with C-rich PNs, which all show very similar IR spectra dominated by PAHs. These spectral variations between transition objects of similar effective temperatures cannot be due to excitation variations but imply compositional variations of the dust. Moreover, this result suggests that circumstellar dust evolves during the transition phase from red giant to PN, perhaps as a result of grain-grain collisions and shattering in the fast winds.

Buss, R. H., Jr.; Tielens, A. G. G. M.; Cohen, M.; Werner, M. W.; Bregman, J. D.; Witteborn, F. C.

1993-01-01

168

Detection of Optically Faint GEO Debris  

NASA Technical Reports Server (NTRS)

There have been extensive optical surveys for debris at geosynchronous orbit (GEO) conducted with meter-class telescopes, such as those conducted with MODEST (the Michigan Orbital DEbris Survey Telescope, a 0.6-m telescope located at Cerro Tololo in Chile), and the European Space Agency's 1.0-m space debris telescope (SDT) in the Canary Islands. These surveys have detection limits in the range of 18th or 19th magnitude, which corresponds to sizes larger than 10 cm assuming an albedo of 0.175. All of these surveys reveal a substantial population of objects fainter than R = 15th magnitude that are not in the public U.S. Satellite Catalog. To detect objects fainter than 20th magnitude (and presumably smaller than 10 cm) in the visible requires a larger telescope and excellent imaging conditions. This combination is available in Chile. NASA's Orbital Debris Program Office has begun collecting orbital debris observations with the 6.5-m (21.3-ft diameter) "Walter Baade" Magellan telescope at Las Campanas Observatory. The goal is to detect objects as faint as possible from a ground-based observatory and begin to understand the brightness distribution of GEO debris fainter than R = 20th magnitude.

Seitzer, P.; Lederer, S.; Barker, E.; Cowardin, H.; Abercromby, K.; Silha, J.; Burkhardt, A.

2014-01-01

169

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.

Mea Cook

170

FAINT RADIO SOURCES AND STAR FORMATION HISTORY  

E-print Network

FAINT RADIO SOURCES AND STAR FORMATION HISTORY Deborah B. Haarsma 1 , R. Bruce Partridge 1 , Ian 85287­1504 USA Abstract. Faint extragalactic radio sources provide important information about the global history of star formation. Sensitive radio observations of the Hubble Deep Field and other fields

Waddington, Ian

171

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

172

FLAMINGOS-2: The Facility Near-Infrared Wide-field Imager & Multi-Object Spectrograph for Gemini  

E-print Network

We report on the design and status of the FLAMINGOS-2 instrument - a 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 mm 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 $\\sim$ 1300 to $\\sim $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 current status of the project, currently in final testing in mid-2006.

Stephen Eikenberry; Richard Elston; S. Nicholas Raines; Jeff Julian; Kevin Hanna; David Hon; Roger Julian; R. Bandyopadhyay; J. Greg Bennett; Aaron Bessoff; Matt Branch; Richard Corley; John-David Eriksen; Skip Frommeyer; Anthony Gonzalez; Michael Herlevich; Antonio Marin-Franch; Jose Marti; Charlie Murphey; David Rashkin; Craig Warner; Brian Leckie; W. Rusty Gardhouse; Murray Fletcher; Jennifer Dunn; Robert Wooff; Tim Hardy

2006-04-27

173

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

174

FLAMINGOS-2: The Facility Near-Infrared Wide-field Imager & Multi-Object Spectrograph for Gemini  

E-print Network

We report on the design and status of the FLAMINGOS-2 instrument - a 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 mm 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 $\\sim$ 1300 to $\\sim $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 current status of the pro...

Eikenberry, S; Bennett, J G; Bessoff, A; Branch, M; Corley, R; Dunn, J; Elston, R; Eriksen, J D; Fletcher, M; Frommeyer, S; Gardhouse, W R; González, A; Hanna, K; Hardy, T; Herlevich, M; Hon, D; Julian, J; Julian, R; Leckie, B; Marin-Franch, A; Martí, J; Murphey, C; Raines, S N; Rashkin, D; Warner, C; Wooff, R; Bessoff, Aaron; Branch, Matt; Corley, Richard; Dunn, Jennifer; Eikenberry, Stephen; Elston, Richard; Eriksen, John-David; Fletcher, Murray; Frommeyer, Skip; Gonzalez, Anthony; Hanna, Kevin; Hardy, Tim; Herlevich, Michael; Hon, David; Julian, Jeff; Julian, Roger; Leckie, Brian; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Rashkin, David; Warner, Craig; Wooff, Robert

2006-01-01

175

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 and status of the FLAMINGOS-2 instrument - a 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 2048×2048-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 6×2-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 3×1-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 current status of the project and future plans, including on-sky delivery planned for late 2008.

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

2008-07-01

176

Design of the solid cryogen dewar for the Near-Infrared Camera and Multi-Object Spectrometer  

NASA Technical Reports Server (NTRS)

A multipurpose, second-generation HST instrument for imaging and spectroscopy in the 1 to 2.5 microns wavelength region is being developed. The Near-Infrared Camera Multi-Object Spectrometer (NICMOS) is unique since it is the only HST instrument operating in the NIR and cryogenically cooled. The NICMOS detector arrays are cooled to 58 K by a solid-nitrogen (SN2) dewar with a predicted lifetime of nearly five years. To obtain this long lifetime, a hybrid cooling approach using thermoelectric coolers (TECs) is employed to reduce the parasitic heat load on the SN2. The design features used to promote long life, the predicted lifetime improvements provided by the TECs, and the performance degradation in the event of TEC failure(s) are discussed.

Oonk, Rodney L.

1991-01-01

177

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

178

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

179

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

180

Infrared Gallery  

NSDL National Science Digital Library

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

WGBH Educational Foundation

2005-10-21

181

Are compact groups hostile towards faint galaxies?  

NASA Astrophysics Data System (ADS)

Aims: The goal of this work is to understand whether the extreme environment of compact groups (CGs) can affect the distribution and abundance of faint galaxies around them. Methods: We performed an analysis of the faint galaxy population in the vicinity of compact and normal groups. We built a light-cone mock galaxy catalogue constructed from the Millennium Run Simulation II plus a semi-analytical model of galaxy formation. We identified a sample of CGs in the mock catalogue as well as a control sample of normal galaxy groups and computed the projected number density profiles of faint galaxies around the first and the second ranked galaxies. We also compared the profiles obtained from the semi-analytical galaxies in CGs with those obtained from observational data. In addition, we investigated whether the ranking or the luminosity of a galaxy is the most important parameter in the determination of the centre around which the clustering of faint galaxies occurs. Results: There is no particular influence of the extreme compact group (CG) environment on the number of faint galaxies in such groups compared to control groups. When selecting normal groups with separations between the first and second ranked galaxies similar to what is observed in CGs, the faint galaxy projected number density profiles in CGs and normal groups are similar in shape and height. We observed a similar behaviour of the population of faint galaxies in observations and simulations in the regions closer to the first and second ranked galaxies. Finally, we find that the projected density of faint galaxies is higher around luminous galaxies, regardless of the ranking in the CG. Conclusions: The semi-analytical approach shows that CGs and their surroundings do not represent a hostile enough environment to make faint galaxies behave differently than in normal groups. Appendix A is available in electronic form at http://www.aanda.org

Zandivarez, Ariel; Díaz-Giménez, Eugenia; Mendes de Oliveira, Claudia; Gubolin, Henrique

2014-12-01

182

Hubble Deep Fever A faint galaxy diagnosis  

E-print Network

The longstanding faint blue galaxy problem is gradually subsiding as a result of technological advancement, most notably from high-resolution Hubble Space Telescope imaging. In particular two categorical facts have recently been established, these are: 1) The excess faint blue galaxies are of irregular morphologies, and, 2) the majority of these irregulars occur at redshifts 1 2. Taking these facts together we favour a scenario where the faint blue excess is primarily due to the formation epoch of spiral systems via merging at redshifts 1 < z < 2. The final interpretation now awaits refinements in our understanding of the local galaxy population !

Driver, S P

1998-01-01

183

Hubble Deep Fever: A faint galaxy diagnosis  

E-print Network

The longstanding faint blue galaxy problem is gradually subsiding as a result of technological advancement, most notably from high-resolution Hubble Space Telescope imaging. In particular two categorical facts have recently been established, these are: 1) The excess faint blue galaxies are of irregular morphologies, and, 2) the majority of these irregulars occur at redshifts 1 2. Taking these facts together we favour a scenario where the faint blue excess is primarily due to the formation epoch of spiral systems via merging at redshifts 1 < z < 2. The final interpretation now awaits refinements in our understanding of the local galaxy population !

S. P. Driver

1998-02-26

184

Comparison of functional near-infrared spectroscopy and electrodermal activity in assessing objective versus subjective risk during risky financial decisions.  

PubMed

Risk is an important factor impacting financial decisions. Risk can be processed objectively, e.g. as variance across possible outcomes of a choice option or subjectively, e.g. as value of that variance to a given individual. The aim of the present study was to test the potential of functional near-infrared spectroscopy (fNIRS) in assessing these different ways of processing risk while subjects decided between either high or low risk financial options or a safe (risk-free) option. For comparison we simultaneously measured electrodermal activity (EDA), a well-established method in decision-making research and a core measure of affective processes. FNIRS showed that lateral prefrontal cortex responses to high risk were enhanced relative to low risk only in risk-seeking individuals but reduced relative to low risk in risk-averse individuals. This is in-line with individual-specific risk processing reflecting the subjective value of risk. By contrast, EDA showed enhanced responses to high risk, independent of individual risk attitude, in-line with the notion of objective risk processing. The dissociation between the two measures arose even though they overall were equally sensitive to detect individual risk-related differences and even though there was an increased, risk attitude-independent, temporal coherence between the two measures during high-risk conditions. Our results suggest that hemodynamic responses in lateral prefrontal cortex as measured by fNIRS reflect the subjective value of risk, whereas EDA may index the objective amount of risk people are presented with. The findings suggest that fNIRS could be a useful method for studying risk behavior in financial decisions. PMID:24096126

Holper, Lisa; Wolf, Martin; Tobler, Philippe N

2014-01-01

185

Infrared and Radio observations of a small group of protostellar objects in the molecular core, L1251-C  

E-print Network

We present a multi-wavelength observational study of a low-mass star-forming region, L1251-C, with observational results at wavelengths from the near-infrared to the millimeter. Spitzer Space Telescope observations confirmed that IRAS 22343+7501 is a small group of protostellar objects. The extended emission to east-west direction with its intensity peak at the center of L1251A has been detected at 350 and 850 micron with the CSO and JCMT telescopes, tracing dense envelope materials around L1251A. The single-dish data from the KVN and TRAO telescopes show inconsistencies between the intensity peaks of several molecular line emission and that of the continuum emission, suggesting complex distributions of molecular abundances around L1251A. The SMA interferometer data, however, show intensity peaks of CO 2-1 and 13CO 2-1 located at the position of IRS 1, which is both the brightest source in IRAC image and the weakest source in the 1.3 mm dust continuum map. IRS 1 is the strongest candidate for the driving sour...

Kim, Jungha; Choi, Minho; Bourke, Tyler L; Evans, Neal J; Di Francesco, James; Cieza, Lucas A; Dunham, Michael M; Kang, Miju

2015-01-01

186

Infrared Waves  

NSDL National Science Digital Library

This webpage, part of a National Aeronautics and Space Administration's 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.

187

Particle-based ablation model for faint meteors  

NASA Astrophysics Data System (ADS)

Modeling the ablation of meteoroids as they enter the atmosphere is a way of determining their physical structure and elemental composition. This can provide insight into the structure of parent bodies when combined with an orbit computed from observations. The Canadian Automated Meteor Observatory (CAMO) is a source of new, high-resolution observations of faint meteors [1]. These faint objects tend to have pre-atmospheric masses around 10^{-5} kg, corresponding to a radius of 1 mm. A wide-field camera with a 28° field of view provides guidance to a high-resolution camera that tracks meteors in flight with 1.5° field of view. Meteors are recorded with a scale of 4 m per pixel at a range of 135 km, at 110 frames per second, allowing us to investigate detailed meteor morphology. This serves as an important new constraint for ablation models, in addition to meteor brightness (lightcurves) and meteoroid deceleration. High-resolution observations of faint meteors have revealed that contemporary ablation models are not able to predict meteor morphology, even while matching the observed lightcurve and meteoroid deceleration [2]. This implies that other physical processes, in addition to fragmentation, must be considered for faint meteor ablation. We present a new, particle-based approach to modeling the ablation of small meteoroids. In this model, we simulate the collisions between atmospheric particles and the meteoroid to determine the rate of evaporation and deceleration. Subsequent collisions simulated between evaporated meteoroid particles and ambient atmospheric particles then produce light that would be observed by high-resolution cameras. Preliminary results show simultaneous agreement with meteor morphology, lightcurves, and decelerations recorded with CAMO. A sample comparison of simulated and observed meteor morphology is given in the attached figure. Several meteoroids are well-represented as solid, stony bodies, but some require modeling as a dustball [3]. Large trail widths in faint meteors observed with CAMO are also explained by the collisional light production emphasized with this model [4]. Ultimately, improving models of meteoroid ablation, such that they are able to satisfy more constraints simultaneously, will provide a better understanding of the composition and structure of objects throughout the Solar System. Particularly, we hope to use this model in the future to quantify meteoroid density and the distribution of particle sizes present in dust-ball bodies.

Stokan, E.; Campbell-Brown, M.

2014-07-01

188

VizieR Online Data Catalog: Faint Blue Stars in high Galactic Latitudes III (Berger+ 1984)  

NASA Astrophysics Data System (ADS)

This is the third and last part of the survey of faint blue objects: a catalogue of 2484 starlike or compact objects is presented with the 1950 positions, estimated magnitudes, color classes and extensive identifications with stars of previous surveys and known QSO's. (2 data files).

Berger, J.; Fringant, A. M.

1997-08-01

189

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

190

The South Pole Near Infrared Sky Brightness  

NASA Astrophysics Data System (ADS)

We report our finding that the South Pole is the darkest known Earth-based site for near infrared astronomical observations. For this reason it has great potentail for the most sensitive surveys of distant or faint objects. We find that the south polar sky background is substantially darker in the standard near infrared J, H, and K filters, and in an optimized K_DARK filter centered at 2.36 microns. In particular, the K_DARK background at the South Pole is only 162 +/- 67 mu-Jy arcsec^-2 at the zenith. This is consistent with the results described in an accompanying paper by Ashley et al. 1996, and is comparable to the sky brightness measured by high altitude balloon in the 2.4 micron (Matsumoto et al. 1994). (SECTION: Atmospheric Phenomena and Seeing)

Nguyen, H. T.; Rauscher, Bernard J.; Severson, Scott A.; Hereld, Mark; Harper, D. A.; Lowenstein, R. F.; Morozek, F.; Pernic, R. J.

1996-08-01

191

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

192

GRAVITY: The adaptive optics assisted, two object beam combiner for the VLTI  

E-print Network

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

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

2006-07-17

193

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

194

The VLTI/MIDI survey of massive young stellar objects . Sounding the inner regions around intermediate- and high-mass young stars using mid-infrared interferometry  

NASA Astrophysics Data System (ADS)

Context. Because of inherent difficulties involved in observations and numerical simulations of the formation of massive stars, an understanding of the early evolutionary phases of these objects remains elusive. In particular, observationally probing circumstellar material at distances ?100 AU from the central star is exceedingly difficult, as such objects are rare (and thus, on average, far away) and typically deeply embedded. Long-baseline mid-infrared interferometry provides one way of obtaining the necessary spatial resolution at appropriate wavelengths for studying this class of objects; however, interpreting such observations is often difficult due to sparse spatial-frequency coverage. Aims: We aim to characterize the distribution and composition of circumstellar material around young massive stars and to investigate exactly which physical structures in these objects are probed by long-baseline mid-infrared interferometric observations. Methods: We used the two-telescope interferometric instrument MIDI of the Very Large Telescope Interferometer of the European Southern Observatory to observe a sample of 24 intermediate- and high-mass young stellar objects in the N band (8-13 ?m). We had successful fringe detections for 20 objects and present spectrally-resolved correlated fluxes and visibility levels for projected baselines of up to 128 m. We fit the visibilities with geometric models to derive the sizes of the emitting regions, as well as the orientation and elongation of the circumstellar material. Fourteen objects in the sample show the 10 ?m silicate feature in absorption in the total and correlated flux spectra. For 13 of these objects, we were able to fit the correlated flux spectra with a simple absorption model, allowing us to constrain the composition and absorptive properties of the circumstellar material. Results: Nearly all of the massive young stellar objects observed show significant deviations from spherical symmetry at mid-infrared wavelengths. In general, the mid-infrared emission can trace both disks and outflows, and in many cases it may be difficult to disentangle these components on the basis of interferometric data alone, because of the sparse spatial frequency coverage normally provided by current long-baseline interferometers. For the majority of the objects in this sample, the absorption occurs on spatial scales larger than those probed by MIDI. Finally, the physical extent of the mid-infrared emission around these sources is correlated with the total luminosity, albeit with significant scatter. Conclusions: Circumstellar material is ubiquitous at distances ?100 AU around young massive stars. Long-baseline mid-infrared interferometry provides the resolving power necessary for observing this material directly. However, in particular for deeply-embedded sources, caution must be used when attempting to attribute mid-infrared emission to specific physical structures, such as a circumstellar disk or an outflow. Appendix A is available in electronic form at http://www.aanda.orgBased on observations with the Very Large Telescope Interferometer of the European Southern Observatory.The reduced interferometric data presented here are available 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/558/A24

Boley, Paul A.; Linz, Hendrik; van Boekel, Roy; Henning, Thomas; Feldt, Markus; Kaper, Lex; Leinert, Christoph; Müller, André; Pascucci, Ilaria; Robberto, Massimo; Stecklum, Bringfried; Waters, L. B. F. M.; Zinnecker, Hans

2013-10-01

195

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

196

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

197

Are compact groups hostile towards faint galaxies?  

E-print Network

The goal of this work is to understand whether the extreme environment of compact groups can affect the distribution and abundance of faint galaxies around them. We performed an analysis of the faint galaxy population in the vicinity of compact groups and normal groups. We built a light-cone mock galaxy catalogue constructed from the Millennium Run Simulation II plus a semi-analytical model of galaxy formation. We identified a sample of compact groups in the mock catalogue as well as a control sample of normal galaxy groups and computed the projected number density profiles of faint galaxies around the first- and the second-ranked galaxies. We also compared the profiles obtained from the semi-analytical galaxies in compact groups with those obtained from observational data. In addition, we investigated whether the ranking or the luminosity of a galaxy is the most important parameter in the determination of the centre around which the clustering of faint galaxies occurs. There is no particular influence of the...

Zandivarez, Ariel; de Oliveira, Claudia Mendes; Gubolin, Henrique

2014-01-01

198

Counter-evolution of faint field galaxies  

Microsoft Academic Search

We adopt a new approach to explore the puzzling nature of faint blue field galaxies. Instead of assuming that the local luminosity function is well defined, we first determine whether any nonevolving set of luminosity functions for different spectral types of galaxies is compatible with the observed marginal distributions in optical and near-IR counts, B-R colors, and redshifts. Exploiting a

David C. Koo; Caryl Gronwall; Gustavo Bruzual A

1993-01-01

199

Resurrection of traditional luminosity evolution models to explain faint fields galaxies  

Microsoft Academic Search

We explore the nature of the evolution of faint field galaxies by assuming that the local luminosity function is not well-defined. We use a non-negative least-squares technique to derive a near optimal set of local luminosity functions for different spectral types of galaxies by fitting to the observed optical and near-infrared counts, B-R colors, and redshift distributions for galaxies with

Caryl Gronwall; David C. Koo

1995-01-01

200

MID-INFRARED PROPERTIES OF LOW-METALLICITY BLUE COMPACT DWARF GALAXIES FROM THE SPITZER INFRARED SPECTROGRAPH  

E-print Network

MID-INFRARED PROPERTIES OF LOW-METALLICITY BLUE COMPACT DWARF GALAXIES FROM THE SPITZER INFRARED. Blue compact dwarfs (BCDs) are a group of extragalactic ob- jects with faint, blue optical colors-infrared (MIR) study of a large sample of blue compact dwarfs (BCDs) using the Infrared Spectrograph (IRS

Spoon, Henrik

201

Moving Objects in the Hubble Ultra Deep Field  

NASA Astrophysics Data System (ADS)

We identify proper motion objects in the Hubble Ultra Deep Field (UDF) using the optical data from the original UDF program in 2004 and the near-infrared data from the 128 orbit UDF 2012 campaign. There are 12 sources brighter than I = 27 mag that display >3? significant proper motions. We do not find any proper motion objects fainter than this magnitude limit. Combining optical and near-infrared photometry, we model the spectral energy distribution of each point-source using stellar templates and state-of-the-art white dwarf models. For I <= 27 mag, we identify 23 stars with K0-M6 spectral types and two faint blue objects that are clearly old, thick disk white dwarfs. We measure a thick disk white dwarf space density of 0.1-1.7 × 10-3 pc-3 from these two objects. There are no halo white dwarfs in the UDF down to I = 27 mag. Combining the Hubble Deep Field North, South, and the UDF data, we do not see any evidence for dark matter in the form of faint halo white dwarfs, and the observed population of white dwarfs can be explained with the standard Galactic models. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

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

2013-09-01

202

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

203

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

204

A faint galaxy redshift survey to B=24  

E-print Network

Using the multislit LDSS-2 spectrograph on the {\\it William Herschel Telescope} we have completed a redshift survey in the magnitude range $22.51$ and includes the highest redshift galaxy ($z=1.108$) yet discovered in a field sample. The median redshift, $\\zmed=0.46$, and form of the redshift distribution constitute compelling evidence against simple luminosity evolution as an explanation of the large excess of faint galaxies ($\\simeq\\times$2--4 no-evolution) seen in this magnitude range. Rather we identify the excess population as blue objects with $z\\sim 0.4$ and $B$\\, luminosities similar to local $L^*$ galaxies indicating a dramatic decrease in the density of such objects over the last Hubble time, confirming the trends found in brighter redshift surveys. We also find a marked absence of {\\it very} low redshift galaxies ($z<$0.1) at faint limits, severely constraining any significant steepening of the local field galaxy luminosity function at low luminosities.

K. Glazebrook; R. Ellis; M. Colless; T. Broadhurst; J. Allington-Smith; N. Tanvir

1995-03-30

205

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

E-print Network

-red (FLIR) image sequences taken from an airborne, moving platform. Ego-motion effects are removed through system. 1 Introduction 1.1 Motivation Forward looking infra-red (FLIR) images are frequently used static FLIR images. A comprehensive recent review by Ratches, Wal- £ This research was supported in part

Strehl, Alexander

206

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

E-print Network

: Forecasting tropical cyclogenesis over the Atlantic basin using large-scale data. MWR, 131, 2927-2940. Knapp, K., 2008: Hurricane Satellite (HURSAT) data sets: Low-earth orbit infrared and microwave data. 28th tropical convection, or "cloud clusters", are a necessary precursor for tropical cyclogenesis. Several past

Hennon, Christopher C.

207

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

208

Moving Objects in the Hubble Ultra Deep Field  

E-print Network

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 >3sigma 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 IUDF 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 ...

Kilic, Mukremin; von Hippel, Ted

2013-01-01

209

Storm Tracking and Monitoring Using Objective Synoptic Diagnosis and Cluster Identification from Infrared Meteosat Imagery: A Case Study  

Microsoft Academic Search

Summary  ?The present paper investigates the potential of combining image processing techniques based on cluster analysis of infrared\\u000a (IR) Meteosat images with dynamic meteorological theory on synoptic systems. From this last point of view the highest probability\\u000a of deep convective development is favoured where the overlapping of four mechanisms acting at synoptic scale is produced:\\u000a upward quasi-geostrophic forcing, convergence of water

M. C. Llasat; C. Ramis; L. Lanza

1999-01-01

210

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

NASA Astrophysics Data System (ADS)

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

Gomez Gonzalez, Laura

2012-01-01

211

A Constant Clustering Amplitude for Faint Galaxies?  

E-print Network

The angular clustering of faint field galaxies is investigated using deep imaging (I~25) obtained with the 10-m Keck-I telescope. The autocorrelation function is consistent with w(theta) ~ theta^-0.8 and, although less steep correlation functions cannot be ruled out with high confidence, we find no compelling evidence for a systematic decrease in the power law index at the faintest magnitude limits. Results from a number of independent observational studies are combined in order to investigate the variation of the correlation amplitude with median I-magnitude. At Imed~23 the results obtained by different studies are all in rough agreement and indicate that for Imed > 22 the correlation amplitude declines far less steeply than would be expected from an extrapolation of the trend in the brighter samples. In particular, at Imed~24 our data indicate w(theta) to be a factor ~7 higher than the extrapolation. A near-independence of magnitude is a general feature of the correlation amplitude in models in which the redshift distribution of the faint field population contains a substantial fraction of galaxies with z > 1. In order to reproduce the apparent abrupt flattening of the amplitude of w(theta) observed at faint limits, approximately 50% of the galaxies in a sample with a depth of I~25 must be at z > 1.

Tereasa G. Brainerd; Ian Smail

1997-12-19

212

Identifications of The Most Luminous, Highest-Redshift Objects Discovered by WISE (Wide-field Infrared Survey Explorer)  

NASA Astrophysics Data System (ADS)

We request 4 nights to obtain KPNO/FLAMINGOS near-IR photometry and spectroscopy follow-up observations of a sample of extremely luminous, z > 1 galaxy candidates selected from WISE, a new NASA mission which is in the process of surveying the whole sky at 3.4,4.6,12 and 22 (micron) in 6 months (Jan-July 2010). The candidates are selected to have mid-IR colors indicating starburst-dominated spectra at redshifts of z=1.2 - 3, but are 100 times more luminous than local ULIRGs with L_FIR > 10^14 L_?, called extreme hyperluminous infrared galaxies (eHyLIRGs). In combination with the WISE mid-infrared photometry, the near-IR photometric and spectroscopic observations will allow us to distinguish high-z targets from local red populations, determine the luminosity, and further study the star formation activity from hydrogen recombination lines, extinction toward the star formation regions, and SED modeling on the stellar population of these galaxies.

Benford, Dominic; Stanford, Adam; Jarrett, Tom; Yan, Lin; Eisenhardt, Peter; Lonsdale, Carol; Wright, Ned; Tsai, Chao-Wei; Blain, Andrew; Cutri, Roc

2010-08-01

213

The Population of Tiny Near-Earth Objects Observed by NEOWISE  

E-print Network

Only a very small fraction of the asteroid population at size scales comparable to the object that exploded over Chelyabinsk, Russia has been discovered to date, and physical properties are poorly characterized. We present previously unreported detections of 106 close approaching near-Earth objects (NEOs) by the Wide-field Infrared Survey Explorer mission's NEOWISE project. These infrared observations constrain physical properties such as diameter and albedo for these objects, many of which are found to be smaller than 100 m. Because these objects are intrinsically faint, they were detected by WISE during very close approaches to the Earth, often at large apparent on-sky velocities. We observe a trend of increasing albedo with decreasing size, but as this sample of NEOs was discovered by visible light surveys, it is likely that selection biases against finding small, dark NEOs influence this finding.

Mainzer, A; Grav, T; Masiero, J; Cutri, R M; Wright, E L; Nugent, C R; Stevenson, R; Clyne, E; Cukrov, G; Masci, F

2013-01-01

214

Optical Line Diagnostics of z~2 Optically Faint ULIRGs in the Spitzer Bootes Survey  

E-print Network

We present near-infrared spectroscopic observations for a sample of ten optically faint luminous infrared galaxies (R-[24]> 14) using Keck NIRSPEC and Gemini NIRI. The sample is selected from a 24 micron Spitzer MIPS imaging survey of the NDWFS Bootes field. We measure accurate redshifts in the range 1.31900 km/s) Halpha or Hbeta emission lines; the remaining three are type II AGN. Given their large mid-IR luminosities and faint optical magnitudes, we might expect these sources to be heavily extincted quasars, and therefore only visible as type II AGN. The visibility of broad lines in 70% of the sources suggests that it is unlikely that these AGN are being viewed through the mid-plane of a dusty torus. For four of the sources we constrain the Halpha/Hbeta Balmer decrement and estimate the extinction to the emission line region to be large for both type I and type II AGN, with A_Halpha > 2.4-5 mag. Since the narrow-line region is also extincted and the UV continuum emission from the host galaxies is extremely faint, this suggests that much of the obscuration is contributed by dust on large (~kpc) scales within the host galaxies. These sources may be examples of "host-obscured" AGN which could have space densities comparable or greater to that of optically luminous type I AGN with similar bolometric luminosities.

K. Brand; A. Dey; V. Desai; B. T. Soifer; C. Bian; L. Armus; M. J. I. Brown; E. Le Floc'h; S. J. Higdon; J. R. Houck; B. T. Jannuzi; D. W. Weedman

2007-02-28

215

Characterization and testing of FLAMINGOS-2: the Gemini facility near-infrared multi-object spectrometer and wide-field imager  

NASA Astrophysics Data System (ADS)

FLAMINGOS-2 is a near-infrared wide-field imager and fully cryogenic multi-object spectrometer for Gemini Observatory being built by the University of Florida. FLAMINGOS-2 can simultaneously carry 9 custom cryogenic multi-object slit masks exchangeable without thermally cycling the entire instrument. Three selectable grisms provide resolving powers which are ~1300 to ~3000 over the entire spectrograph bandpass of 0.9-2.5 microns. We present and discuss characterization data for FLAMINGOS-2 including imaging throughput, image quality, spectral performance, and noise performance. After a lengthy integration process, we expect that FLAMINGOS-2 will be in the midst of commissioning at Gemini South by the fall of 2008.

Raines, Steven N.; Eikenberry, Stephen S.; Bandyopadhyay, Reba M.; Julian, Jeffrey A.; Hanna, Kevin T.; Warner, Craig D.; Julian, Roger E.; Bennett, J. Greg; DeWitt, Curtis N.; Frommeyer, Skip; Gonzalez, Anthony; Herlevich, Michael D.; Murphey, Charles

2008-07-01

216

Infrared Astronomy  

NSDL National Science Digital Library

Despite the claims of certain science fiction novels and films, humans cannot see in infrared. As many people know, the primary source of infrared radiation is heat, and the study of infrared astronomy allows scientists to detect radiation emitted from objects throughout the universe. This delightful website (created by NASA and the Infrared Processing and Analysis Center at the California Institute of Technology) provides a wide range of material on this fascinating area of scientific study. Visitors can lean about the discovery of infrared, learn about the technology that is used in such endeavors, and of course, look over dozens of infrared images and video clips. Educators will be glad to learn that there are a number of activities offered here for use in the classroom, including one that will help students learn how to build a photocell detector.

Hermans-Killam, Linda

217

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

218

The substellar mass function in sigma Orionis. II. Optical, near-infrared and IRAC/Spitzer photometry of young cluster brown dwarfs and planetary-mass objects  

E-print Network

We investigate the mass function in the substellar domain down to a few Jupiter masses in the young sigma Orionis open cluster (3+/-2 Ma, d = 360^+70_-60 pc). We have performed a deep IJ-band search, covering an area of 790 arcmin^2 close to the cluster centre. This survey was complemented with an infrared follow-up in the HKs- and Spitzer 3.6-8.0 mum-bands. Using colour-magnitude diagrams, we have selected 49 candidate cluster members in the magnitude interval 16.1 mag < I < 23.0 mag. Accounting for flux excesses at 8.0 mum and previously known spectral features of youth, 30 objects are bona fide cluster members. Four are first identified from our optical-near infrared data. Eleven have most probable masses below the deuterium burning limit and are classified as planetary-mass object candidates. The slope of the substellar mass spectrum (Delta N / Delta M = a M^-alpha) in the mass interval 0.11 Msol M < 0.006 Msol is alpha = +0.6+/-0.2. Any opacity mass-limit, if these objects form via fragmentation, may lie below 0.006 Msol. The frequency of sigma Orionis brown dwarfs with circumsubstellar discs is 47+/-15 %. The continuity in the mass function and in the frequency of discs suggests that very low-mass stars and substellar objects, even below the deuterium-burning mass limit, may share the same formation mechanism.

J. A. Caballero; V. J. S. Béjar; R. Rebolo; J. Eislöffel; M. R. Zapatero Osorio; R. Mundt; D. Barrado y Navascués; G. Bihain; C. A. L. Bailer-Jones; T. Forveille; E. L. Martín

2007-05-07

219

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

220

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

221

Thermal Infrared Remote Sensing  

E-print Network

detect differences in thermal infrared energy because they see only short wavelength visible light from 0 of the landscape. IMPORTANT: NEAR-INFRARED is short enough wavelength to behave like visible light (can of light! Thermal infrared energyThermal infrared energy is emitted from all objects that have ais emitted

222

Exploring the faint source population at 15.7 GHz  

NASA Astrophysics Data System (ADS)

A sample of 296 faint (> 0.5 mJy) radio sources is selected from an area of the Tenth Cambridge (10C) survey at 15.7 GHz in the Lockman Hole. The 10C survey is complete to 0.5 mJy at 15.7 GHz and has a resolution of 30 arcsec. By matching this catalogue to several lower frequency surveys (e.g. including a deep GMRT survey at 610 MHz, a WSRT survey at 1.4 GHz, NVSS, FIRST and WENSS) I have investigated the radio spectral properties of the sources in this sample; all but 30 of the 10C sources are matched to a source in one or more of these surveys. I have found a significant increase in the proportion of flat spectrum sources at flux densities below 1 mJy -- the median spectral index between 15.7 GHz and 610 MHz changes from 0.75 for flux densities greater than 1.5 mJy to 0.08 for flux densities less than 0.8 mJy. Thus a population of faint, flat spectrum sources is emerging at flux densities greater than approximately 1 mJy. The spectral index distribution of this sample of sources selected at 15.7 GHz is compared to those of two samples selected at 1.4 GHz from FIRST and NVSS. I find that there is a significant flat spectrum population present in the 10C sample which is missing from the samples selected at 1.4 GHz. The 10C sample is compared to a sample of sources selected from the SKADS Simulated Sky by Wilman et al.; this simulation fails to reproduce the observed spectral index distribution and significantly under predicts the number of sources in the faintest flux density bin. I conclude that it is likely that the observed faint, flat spectrum sources are a result of the cores of FRI sources becoming dominant at high frequencies, rather than the emergence of a new population of starforming galaxies. I have used recent Very Long Baseline Interferometry (VLBI) observations by Middleberg et al. with a resolution of 10 mas to investigate the properties of these faint 10C sources in the Lockman Hole and find that 33 out of the 51 10C sources in the VLBI field (65 percent) are detected by the VLBI observations. The high brightness temperature of these VLBI-detected sources rules out the possibility that this faint, high frequency population is dominated by starbursting or starforming sources and indicates that they must be Active Galactic Nuclei. The sources in the Lockman Hole 10C sample are matched to optical, infrared and Xray data available in the field. A complete sample of 96 sources with high-resolution radio information available is defined; multi-wavelength counterparts are identified for 80 out of the 96 sources in this sample, for which is it possible to derive photometric redshifts. The radio-to-optical ratios of these sources show that the 10C sample is almost completely dominated by radio galaxies. 59/80 sources have luminosities greater than the FRI/FRII dividing luminosity. The nature of these radio galaxies is investigated, using the multi-wavelength data to split the sources into high-excitation and low-excitation radio galaxies (HERGs and LERGs respectively). This shows that 34 sources are probably HERGs and 33 are probably LERGs, with 29 which could not be classified at this stage. The properties of these HERGs and LERGs are compared and I find that the HERGs tend to be found at higher redshifts, have flatter spectra, higher flux densities and smaller linear sizes. This study is extended to lower flux densities using new, very deep, observations made with the Arcminute Microkelvin Imager in two fields. I use these observations to extend the 15.7-GHz source count down to 0.1 mJy, a factor of five deeper than the 10C count. These new deeper counts are consistent with the extrapolation of the fit to the 10C count, and do not show any evidence for an upturn. There is therefore no evidence for a new population (e.g. of starforming sources) contributing to the 15.7 GHz source count above 0.1 mJy, and suggesting that the faint, high-frequency population continues to be dominated by radio galaxies. Recent models of the high-frequency source counts under-predict the number of sources observed by a factor of

Whittam, Imogen

2014-10-01

223

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

NASA Technical Reports Server (NTRS)

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

Sanders, David B.

1997-01-01

224

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

PubMed Central

Objectives To determine how often Shakespeare's characters faint, fit, or die from extreme emotion; to assess Shakespeare's uniqueness in this regard; and to examine the plausibility of these dramatised events. Design Line by line search through modern editions of these late 16th and early 17th century works for accounts of characters fainting, fitting, or dying while under strong emotion and for no other apparent reason. Data sources All 39 canonical plays by Shakespeare and his three long narrative poems; 18 similar works by seven of Shakespeare's best known contemporaries. Results 10 deaths from strong emotion are recorded by Shakespeare (three occur on stage); all are due to grief, typically at the loss of a loved one. All but two of the deaths are in the playwright's late works. Some deaths are sudden. Another 29 emotion induced deaths are mentioned as possible, but the likelihood of some can be challenged. Transient loss of consciousness is staged or reported in 18 cases (sounding like epilepsy in two) and near fainting in a further 13. Extreme joy is sometimes depicted as a factor in these events. Emotional death and fainting also occur occasionally in works by Shakespeare's contemporaries. Conclusions These dramatic phenomena are part of the early modern belief system but are also plausible by modern understanding of physiology and disease. They teach us not to underestimate the power of the emotions to disturb bodily functions. PMID:17185734

2006-01-01

225

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

226

Clustering of Faint Galaxies: $\\\\w $, Induced by Weak Gravitational Lensing  

Microsoft Academic Search

Weak gravitational lensing by large scale structure affects the number counts of faint galaxies through the ``magnification bias'' and thus affects the measurement of the angular two-point correlation function $\\\\w $. At faint magnitudes the clustering amplitude will decrease differently with limiting magnitude than expected from Limber's equation. The amplitude will hit a minimum and then rise with limiting magnitude.

Jens Verner Villumsen; Max Planck; Karl Schwarzschild-Str

1995-01-01

227

First Results from the ISO-IRAS Faint Galaxy Survey  

Microsoft Academic Search

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

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

1998-01-01

228

Photometric study of faint early-type stars in the southern Milky Way  

Microsoft Academic Search

We present UBV photoelectric observations for 101 faint early-type (mainly OB) stars in four regions of the Southern Milky Way: two in Vela, one in Centaurus, and one in Circinus; H..beta.. data are also given for the brightest stars. Objective prism plates showing the H..cap alpha.. region of the spectrum are used, together with published results from other authors, to

J. C. Muzzio

1979-01-01

229

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

230

Is the faint young Sun paradox solved?  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

231

Infrared Telescope in Space Observations of the Near-Infrared Extragalactic Background Light  

Microsoft Academic Search

We have searched for near-infrared extragalactic background light (EBL) in the data from the Near-Infrared Spectrometer (NIRS) on the Infrared Telescope in Space (IRTS). After subtracting the contribution of faint stars and the zodiacal component based on modeling, a significant isotropic emission is obtained in the wavelength bands from 1.4 to 4.0 mum. The spectrum is stellar-like but shows a

T. Matsumoto; S. Matsuura; H. Murakami; M. Tanaka; M. Freund; M. Lim; M. Cohen; M. Kawada; M. Noda

2005-01-01

232

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

233

On using a space telescope to detect faint galaxies  

NASA Technical Reports Server (NTRS)

Observations using space telescopes should be optimized for conditions that prevail in space. Since the sky at 1 micron is very dark above the OH nightglow, and because distant galaxies are brightest at wavelength greater than 1 micron, the Hubble space telescope should be very good at detecting and measuring faint, distant galaxies in the R and I bands. For later-generation space telescopes the optimal wavelength for detecting high-redshift faint galaxies is the 3 micron window in the zodiacal light. Observations of faint galaxies in the 1-3 micron region will be less affected by evolution than optical observations, leading to a better determination of q0.

Wright, E. L.

1985-01-01

234

Optical Line Diagnostics of z~2 Optically Faint ULIRGs in the Spitzer Bootes Survey  

E-print Network

We present near-infrared spectroscopic observations for a sample of ten optically faint luminous infrared galaxies (R-[24]> 14) using Keck NIRSPEC and Gemini NIRI. The sample is selected from a 24 micron Spitzer MIPS imaging survey of the NDWFS Bootes field. We measure accurate redshifts in the range 1.31900 km/s) Halpha or Hbeta emission lines; the remaining three are type II AGN. Given their large mid-IR luminosities and faint optical magnitudes, we might expect these sources to be heavily extincted quasars, and therefore only visible as type II AGN. The visibility of broad lines in 70% of the sources suggests that it is unlikely that these AGN are being viewed through the mid-plane of a dusty torus. For four of the sources we constrain the Halpha/Hbeta Balmer decrement and estimate the extinction to the emission line region to be large for both type I and type II AGN, with A_Halpha > 2.4-5 mag. Since the narrow-line region is also extincted and the UV continuum emission from the host galaxies is extremely ...

Brand, K; Desai, V; Soifer, B T; Bian, C; Armus, L; Brown, M J I; Le Floc'h, E; Higdon, S J; Houck, J R; Jannuzi, B T; Weedman, D W

2007-01-01

235

Exploring three faint source detections methods for aperture synthesis radio images  

NASA Astrophysics Data System (ADS)

Wide-field radio interferometric images often contain a large population of faint compact sources. Due to their low intensity/noise ratio, these objects can be easily missed by automated detection methods, which have been classically based on thresholding techniques after local noise estimation. The aim of this paper is to present and analyse the performance of several alternative or complementary techniques to thresholding. We compare three different algorithms to increase the detection rate of faint objects. The first technique consists of combining wavelet decomposition with local thresholding. The second technique is based on the structural behaviour of the neighbourhood of each pixel. Finally, the third algorithm uses local features extracted from a bank of filters and a boosting classifier to perform the detections. The methods' performances are evaluated using simulations and radio mosaics from the Giant Metrewave Radio Telescope and the Australia Telescope Compact Array. We show that the new methods perform better than well-known state of the art methods such as SEXTRACTOR, SAD and DUCHAMP at detecting faint sources of radio interferometric images.

Peracaula, M.; Torrent, A.; Masias, M.; Lladó, X.; Freixenet, J.; Martí, J.; Sánchez-Sutil, J. R.; Muñoz-Arjonilla, A. J.; Paredes, J. M.

2015-04-01

236

arXiv:1204.3473v1[astro-ph.SR]16Apr2012 Mid-Infrared Spectral Variability Atlas of Young Stellar Objects  

E-print Network

arXiv:1204.3473v1[astro-ph.SR]16Apr2012 Mid-Infrared Spectral Variability Atlas of Young Stellar. Henning7 M. Kun3 Ch. Leinert7 A. Mo´or3 N. J. Turner8 ABSTRACT Optical and near-infrared variability that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying 1 Leiden

Henning, Thomas

237

3. Goodbye Creek Picnic ground turnaround. Old rightofway faintly visible ...  

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

3. Goodbye Creek Picnic ground turnaround. Old right-of-way faintly visible in distance. View N. - Crater Lake National Park Roads, Goodbye Creek Bridge, Spanning Goodbye Creek at Munson Valley Road, Klamath Falls, Klamath County, OR

238

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

239

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

240

Super-large-scale structures in the distribution of infrared galaxies.  

NASA Astrophysics Data System (ADS)

The authors report the results of searching typical scales for distribution of infrared galaxies. The samples analysed included the samples provided by the QDOT redshift survey and the samples sorted out from the IRAS faint sources catalog.

Deng, Zugan; Xia, Xiaoyang; Börner, G.

1999-08-01

241

Extremely faint, diffuse satellite systems in the M31 halo: exceptional star clusters or tiny dwarf galaxies?  

NASA Astrophysics Data System (ADS)

Recent years have seen the discovery of a variety of low surface brightness, diffuse stellar systems in the Local Group. Of particular prominence are the ultra-faint dwarf satellites of the Milky Way and the extended globular clusters seen in M31, M33, and NGC 6822. As part of the major Pan-Andromeda Archaeological Survey {PAndAS} we have discovered several very faint and diffuse stellar satellites in the M31 halo. In Cycle 19 we obtained ACS/WFC imaging for one of these, PAndAS-48, which has revealed it to be a puzzling and unusual object. On the size-luminosity plane it falls between the extended clusters and ultra-faint dwarfs; however, its characteristics do not allow us to unambiguously class it as either type of system. If PAndAS-48 is an extended cluster then it is the most elliptical, isolated, metal-poor, and lowest-luminosity example yet uncovered. Conversely, while its properties are generally consistent with those observed for the faint dwarf satellites of the Milky Way, it would be a factor 2-3 smaller in spatial extent than its Galactic counterparts at comparable luminosity. Here we propose deep resolved imaging of the remaining five similar objects in our sample, with the aim of probing this hitherto poorly-explored region of parameter space in greater detail. If we are able to confirm any of these objects as faint dwarfs, they will provide the first insight into the behaviour of this class of object in a galaxy other than the Milky Way.

Mackey, Dougal

2013-10-01

242

Measuring the Undetectable: Proper Motions and Parallaxes of Very Faint Sources  

NASA Astrophysics Data System (ADS)

The near future of astrophysics involves many large solid-angle, multi-epoch, multiband imaging surveys. These surveys will, at their faint limits, have data on a large number of sources that are too faint to be detected at any individual epoch. Here, we show that it is possible to measure in multi-epoch data not only the fluxes and positions, but also the parallaxes and proper motions of sources that are too faint to be detected at any individual epoch. The method involves fitting a model of a moving point source simultaneously to all imaging, taking account of the noise and point-spread function (PSF) in each image. By this method it is possible to measure the proper motion of a point source with an uncertainty close to the minimum possible uncertainty given the information in the data, which is limited by the PSF, the distribution of observation times (epochs), and the total signal-to-noise in the combined data. We demonstrate our technique on multi-epoch Sloan Digital Sky Survey (SDSS) imaging of the SDSS Southern Stripe (SDSSSS). We show that with our new technique we can use proper motions to distinguish very red brown dwarfs from very high-redshift quasars in these SDSS data, for objects that are inaccessible to traditional techniques, and with better fidelity than by multiband imaging alone. We rediscover all 10 known brown dwarfs in our sample and present nine new candidate brown dwarfs, identified on the basis of significant proper motion.

Lang, Dustin; Hogg, David W.; Jester, Sebastian; Rix, Hans-Walter

2009-05-01

243

A peculiar faint satellite in the remote outer halo of M31  

E-print Network

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 > 10 Gyr and [Fe/H] PAndAS-48 is most likely a remote M31 satellite with a 3D galactocentric radius of 149 (+19 -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 rh = 26 (+4 -3) pc, integrated luminosity Mv = -4.8 +/- 0.5, and ellipticity = 0.30 (+0.08 -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...

Mackey, Dougal; Martin, Nicolas; Ferguson, Annette; Dotter, Aaron; McConnachie, Alan; Ibata, Rodrigo; Irwin, Mike; Lewis, Geraint; Sakari, Charli; Tanvir, Nial; Venn, Kim

2013-01-01

244

An XMM-Newton view of the young open cluster NGC 6231 - III. Optically faint X-ray sources  

Microsoft Academic Search

We discuss the properties of the X-ray sources with faint optical counterparts in the very young open cluster NGC 6231. From their positions in the Hertzsprung-Russell diagram, we find that the bulk of these objects probably consists of low-mass pre-main-sequence (PMS) stars with masses in the range 0.3-3.0 Msolar. The age distribution of these objects indicates that low-mass star formation

H. Sana; G. Rauw; H. Sung; E. Gosset; J.-M. Vreux

2007-01-01

245

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

246

A Peculiar Faint Satellite in the Remote Outer Halo of M31  

NASA Astrophysics Data System (ADS)

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 >~ 10 Gyr and [Fe/H] lsim -2.3. Our inferred distance modulus (m - M)0 = 24.57 ± 0.11 confirms that PAndAS-48 is most likely a remote M31 satellite with a three-dimensional galactocentric radius of 149^{+19}_{-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_h=26^{+4}_{-3} pc, integrated luminosity MV = -4.8 ± 0.5, and ellipticity \\epsilon =0.30^{+0.08}_{-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 ~2-3 smaller in spatial extent than any known counterpart of comparable luminosity. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), 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 GO 12515.

Mackey, A. D.; Huxor, A. P.; Martin, N. F.; Ferguson, A. M. N.; Dotter, A.; McConnachie, A. W.; Ibata, R. A.; Irwin, M. J.; Lewis, G. F.; Sakari, C. M.; Tanvir, N. R.; Venn, K. A.

2013-06-01

247

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

248

METHODS FOR ESTIMATING FLUXES AND ABSORPTIONS OF FAINT X-RAY SOURCES  

SciTech Connect

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 approx2000 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., E-mail: gkosta@astro.psu.ed [Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States)

2010-01-10

249

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

250

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

251

Impacting small Near Earth Objects  

Microsoft Academic Search

The design of a low-cost spacecraft to impact on a small, faint Near Earth Object (NEO), poses major challenges. This paper focuses on the terminal phase of such impact mission, analyzing the capability of autonomous Guidance, Navigation and Control (GNC) systems to compensate the deviations in the impact point to achieve a successful collision. The autonomous GNC system employs the

J. Gil-Fernández; R. Panzeca; C. Corral

2008-01-01

252

VizieR Online Data Catalog: A search for faint blue stars. (Berger+, 1977-84)  

NASA Astrophysics Data System (ADS)

Continuing the survey for faint blue stars at high galactic latitudes of Haro and Luyten (1962, Cat. , this search was made, following the Tonantzintla three image method, with the 48" Schmidt telescope of Mt. Palomar. In this first paper, a catalogue of 4431 stars and 84 compact objects found in nine PSS fields scattered around the NGP is presented, with the 1950 positions and the estimated magnitudes and colour classes. The catalogue contains also extensive identifications with previous surveys, including some known QSSs; 16 QSS candidates are proposed; spectra are available for most of the unknown stars brighter than 14mag. In the second paper, a catalogue of 2011 stars and compact objects is presented with the 1950 positions and the estimated magnitude and colour classes. Complementary to the catalogue of Haro and Luyten (1962BITon...3...37H) at declination +6° and 0° it contains also extensive identifications with previous surveys and known QSO's; candidate QSO's are indicated; spectra are available for some new blue stars. The third and last part of the survey of faint blue objects contains a catalogue of 2484 starlike or compact objects is presented with the 1950 positions, estimated magnitudes, color classes and extensive identifications with stars of previous surveys and known QSO's. (2 data files).

Berger, J.; Fringant, A. M.

2001-03-01

253

VizieR Online Data Catalog: A search for faint blue stars. (Berger+, 1977-84)  

NASA Astrophysics Data System (ADS)

Continuing the survey for faint blue stars at high galactic latitudes of Haro and Luyten (1962, Cat. , this search was made, following the Tonantzintla three image method, with the 48" Schmidt telescope of Mt. Palomar. In the first paper, a catalogue of 4431 stars and 84 compact objects found in nine PSS fields scattered around the NGP is presented, with the 1950 positions and the estimated magnitudes and colour classes. The catalogue contains also extensive identifications with previous surveys, including some known QSSs; 16 QSS candidates are proposed; spectra are available for most of the unknown stars brighter than 14mag. In the second paper, a catalogue of 2011 stars and compact objects is presented with the 1950 positions and the estimated magnitude and colour classes. Complementary to the catalogue of Haro and Luyten (1962BITon...3...37H) at declination +6° and 0° it contains also extensive identifications with previous surveys and known QSO's; candidate QSO's are indicated; spectra are available for some new blue stars. The third and last part of the survey of faint blue objects contains a catalogue of 2484 starlike or compact objects is presented with the 1950 positions, estimated magnitudes, color classes and extensive identifications with stars of previous surveys and known QSO's. The three parts were merged into a single file "catalog.dat". (2 data files).

Berger, J.; Fringant, A. M.

2001-03-01

254

The faint end of the luminosity function in clusters  

E-print Network

I review recent measurements of the faint end of the galaxy luminosity function in galaxy clusters. Evidence is presented that the luminosity function of galaxies in the central parts of clusters is remarkably constant between clusters and that this luminosity function is steep at bright and faint magnitudes and shallow in-between. The curvature is highly significant -- neither a power-law nor a Schechter function is consistent with the data. At no magnitude does alpha=-1 fit the data well. The faintest galaxies in all clusters that have been studied are dwarf spheroidal galaxies.

Neil Trentham

1998-04-01

255

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

256

The Ensemble Variability Properties of Faint QSOs  

Microsoft Academic Search

A refined sample of 64 variable objects with stellar image structure has been\\u000aidentified in SA 57 to $B \\\\sim 22.5$, over a time baseline of 15 years, sampled\\u000aat 11 distinct epochs. The photometric data typically have a root-mean-square\\u000aerror at $B = 22$ of only 0.05 mag. Thirty-five quasars in this field have\\u000aalready been spectroscopically confirmed, 34

Dario Trevese; Richard G. Kron; Steven R. Majewski; Matthew A. Bershady; David C. Koo

1994-01-01

257

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

258

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

259

The Infrared Hunter  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

This image composite compares infrared and visible views of the famous Orion nebula and its surrounding cloud, an industrious star-making region located near the hunter constellation's sword. The infrared picture is from NASA's Spitzer Space Telescope, and the visible image is from the National Optical Astronomy Observatory, headquartered in Tucson, Ariz.

In addition to Orion, two other nebulas can be seen in both pictures. The Orion nebula, or M42, is the largest and takes up the lower half of the images; the small nebula to the upper left of Orion is called M43; and the medium-sized nebula at the top is NGC 1977. Each nebula is marked by a ring of dust that stands out in the infrared view. These rings make up the walls of cavities that are being excavated by radiation and winds from massive stars. The visible view of the nebulas shows gas heated by ultraviolet radiation from the massive stars.

Above the Orion nebula, where the massive stars have not yet ejected much of the obscuring dust, the visible image appears dark with only a faint glow. In contrast, the infrared view penetrates the dark lanes of dust, revealing bright swirling clouds and numerous developing stars that have shot out jets of gas (green). This is because infrared light can travel through dust, whereas visible light is stopped short by it.

The infrared image shows light captured by Spitzer's infrared array camera. Light with wavelengths of 8 and 5.8 microns (red and orange) comes mainly from dust that has been heated by starlight. Light of 4.5 microns (green) shows hot gas and dust; and light of 3.6 microns (blue) is from starlight.

2006-01-01

260

Confirmation of Faint Dwarf Galaxies in the M81 Group  

E-print Network

We have followed up on the results of a 65 square degree 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_r' = -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...

Chiboucas, Kristin; Tully, R Brent; Karachentsev, Igor D

2013-01-01

261

Confirmation of Faint Dwarf Galaxies in the M81 Group  

NASA Astrophysics Data System (ADS)

We have followed up on the results of a 65 deg2 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_{r^{\\prime }} = -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 Re ~ 100 pc and total magnitude estimates M_{r^{\\prime }} = -6.8 and MI ~ -9.1.

Chiboucas, Kristin; Jacobs, Bradley A.; Tully, R. Brent; Karachentsev, Igor D.

2013-11-01

262

5-Polarization Not for the faint of heart.  

E-print Network

5- Polarization Not for the faint of heart. Here there truly be dragons.... #12;Preliminaries #12. . . . #12;Polarization profile (solid line) and extinction profile (dotted line) in the silicate band But 3.4 µm organic band is not polarized - can't be coating silicates? (sphere) #12;HD 204827 HD 99872 P

Sitko, Michael L.

263

Lidar waveform stacking techniques for faint ground return extraction  

NASA Astrophysics Data System (ADS)

Innovative algorithm development for small-footprint full-waveform lidar data processing extends this technology's capabilities to more complicated acquisition scenarios then previously determined, namely success of surveys over obscured areas. Waveform decomposition and the extraction of waveform metrics provide a straightforward approach to identifying vertical structure within each laser measurement. However, there are some limitations in this approach as faint returns within the waveform go undetected within the classical processing chain. These faint returns are the result of reduced energy levels due to obscurant scattering, attenuation and absorption. Lidar surveys over non-homogeneous wooded regions indicate that there are meaningful ground returns within dense tree coverage if extracted correctly from the data. By using a waveform stacking technique with appropriate waveforms in near geospatial proximity to the original, these faint returns can be augmented and detected during data processing. In comparison to the traditional approach, the waveform stacking technique provides up to a 60% increase in perceived ground returns with the faint signal extraction for the particular datasets analyzed over a broadleaf forest in Mississippi. The enhanced capability in the presence of foliage provides a decrease in operational effort associated with data density, dwell or targeting techniques, in addition to required survey expense.

Magruder, Lori A.; Neuenschwander, Amy L.; Marmillion, Scott P.

2010-01-01

264

The faint end of the galaxy luminosity function  

E-print Network

We present and discuss optical measurements of the faint end of the galaxy luminosity function down to M_R = -10 in five different local environments of varying galaxy density and morphological content. The environments we studied, in order of decreasing galaxy density, are the Virgo Cluster, the NGC 1407 Group, the Coma I Group, the Leo Group and the NGC 1023 Group. Our results come from a deep wide-angle survey with the NAOJ Subaru 8 m Telescope on Mauna Kea and are sensitive down to very faint surface-brightness levels. Galaxies were identified as group or cluster members on the basis of their surface brightness and morphology. The faintest galaxies in our sample have R ~ 22.5. There were thousands of fainter galaxies but we cannot distinguish cluster members from background galaxies at these faint limits so do not attempt to determine a luminosity function fainter than M_R = -10. In all cases, there are far fewer dwarfs than the numbers of low mass halos anticipated by cold dark matter theory. The mean logarithmic slope of the luminosity function between M_R = -18 and M_R = -10 is alpha ~ -1.2, far shallower than the cold dark matter mass function slope of alpha ~ -1.8. We would therefore need to be missing about 90 per cent of the dwarfs at the faint end of our sample in all the environments we study to achieve consistency with CDM theory.

Neil Trentham; R. Brent Tully

2002-05-04

265

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

266

DISCOVERIES FROM A NEAR-INFRARED PROPER MOTION SURVEY USING MULTI-EPOCH TWO MICRON ALL-SKY SURVEY DATA  

SciTech Connect

We have conducted a 4030 deg{sup 2} 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.

Kirkpatrick, J. Davy; Cutri, Roc M. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Looper, Dagny L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Burgasser, Adam J. [Center for Astrophysics and Space Science, University of California, San Diego, CA 92093 (United States); Schurr, Steven D. [Planck Science Center, MS 220-6, California Institute of Technology, Pasadena, CA 91125 (United States); Cushing, Michael C. [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Cruz, Kelle L. [Department of Physics and Astronomy, Hunter College, New York, NY 10065 (United States); Sweet, Anne C. [British Consulate, San Francisco, CA 94104 (United States); Knapp, Gillian R. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Barman, Travis S. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Bochanski, John J. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 37, Cambridge, MA 02139 (United States); Roellig, Thomas L. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-1000 (United States); McLean, Ian S. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1562 (United States); McGovern, Mark R. [Antelope Valley College, Lancaster, CA 93536 (United States); Rice, Emily L., E-mail: davy@ipac.caltech.ed [American Museum of Natural History, New York, NY 10024 (United States)

2010-09-15

267

The Enigmatic Young Object: Walker 90/V590 Monocerotis  

E-print Network

We assess the evolutionary status of the intriguing object Walker 90/V590 Mon, which is located about 20 arcminutes northwest of the Cone Nebula near the center of the open cluster NGC 2264. This object, according to its most recent optical spectral type determination (B7), which we confirmed, is at least 3 magnitudes too faint in V for the cluster distance, but it shows the classical signs of a young pre-main sequence object, such as highly variable Halpha emission, Mg II emission, IR excess, UV continuum, and optical variability. We analyzed a collection of archival and original data on Walker 90, covering 45 years including photometry, imaging, and spectroscopic data ranging from ultraviolet to near-infrared wavelengths. According to star formation processes, it is expected that, as this object clears its primordial surroundings, it should become optically brighter, show a weakening of its IR excess and present decreasing line emissions. This behavior is supported by our observations and analysis, but timescales are expected to be longer than the one observed here. Based on photometric data secured in 2007, we find Walker 90 at its brightest recorded optical magnitude. We document an evolution in spectral type over the past five decades (from A2/A3 to currently B7 and as early as B4), along with a decrease in the near-infrared K fluxes. From near-infrared images secured in 2004, Walker 90 appears as a point source placing an upper limit of 0.1 arcsec for its diameter. We conclude that many observational features are explained if W90 is a flared disk system, surrounded by an inclined optically thick accretion disk.

Mario R. Perez; Bruce McCollum; Mario E. van den Ancker; Michael D. Joner

2008-05-27

268

On the Poisson Approximation to Photon Distribution for Faint Lasers Yucheng Hua  

E-print Network

On the Poisson Approximation to Photon Distribution for Faint Lasers Yucheng Hua , Xiang Pengb statistics for attenuated faint laser pulses is quantitatively studied. It confirms that, even for a non-Poissonian laser source, after being attenuated into faint laser with ultra-low mean photon number, the photon

Lu, Tiao

269

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

270

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

271

The Inferred Redshift Distribution of the Faint Blue Galaxy Excess  

Microsoft Academic Search

We infer the redshift distribution of the faint blue galaxy excess (FBE) at mB = 23.5 by subtracting the predicted distribution of giant\\/normal galaxies from the observed N(z) distribution for all types. This is possible because of the recent deep Hubble Space Telescope (HST) WFPC2 morphological number counts that have convincingly demonstrated that little evolution of the giant population is

Simon P. Driver; Warrick J. Couch; Steven Phillipps; Rogier A. Windhorst

1996-01-01

272

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

273

An HST study of three very faint GRB host galaxies  

E-print Network

As part of the HST/STIS GRB host survey program we present the detection of three faint gamma-ray burst (GRB) host galaxies based on an accurate localisation using ground-based data of the optical afterglows (OAs). A common property of these three hosts is their extreme faintness. The location at which GRBs occur with respect to their host galaxies and surrounding environments are robust indicators of the nature of GRB progenitors. The bursts studied here are among the four most extreme outliers, in terms of relative distance from the host center, in the recent comprehensive study of Bloom et al. 2002. We obtain a revised and much higher probability that the galaxies identified as hosts indeed are related to the GRBs (P(n_chance)=0.78, following Bloom et al. 2002), thereby strengthening the conclusion that GRBs are preferentially located in star-forming regions in their hosts. Apart from being faint, the three hosts consist of multiple structures, indicative of merging and active star-formation. For one of the hosts, GRB 980329, we estimate a photometric redshift of z~3.5.

A. O. Jaunsen; M. I. Andersen; J. Hjorth; J. P. U. Fynbo; S. T. Holland; B. Thomsen; J. Gorosabel; B. E. Schaefer; G. Bjornsson; P. Natarajan; N. R. Tanvir

2002-04-18

274

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

275

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

276

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

277

Infrared Heaters  

NASA Technical Reports Server (NTRS)

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

1979-01-01

278

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

279

Object Oriented Learning Objects  

ERIC Educational Resources Information Center

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

Morris, Ed

2005-01-01

280

Optical flares from the faint mid-dM star 2MASS J00453911+4140396  

E-print Network

We present $B$ and $V$ light curves of a large stellar flare obtained with the Wide Field Camera at the Isaac Newton 2.5-m telescope (La Palma). The source object is a faint ($m_V=21.38$) foreground star in the field of the Andromeda galaxy, with its most probable spectral type being dM4. We provide an estimate of the total flare energy in the optical range and find it to be of the order of $10^{35}$ erg. The cooling phase of the large flare shows three additional weak flare-like events, which we interpret as results of a triggering mechanism also observed on the Sun during large coronal mass ejections.

Zs. K?vári; F. Vilardell; I. Ribas; K. Vida; L. van Driel-Gesztelyi; C. Jordi; K. Oláh

2007-11-05

281

The inferred redshift distribution of the faint blue excess  

Microsoft Academic Search

We infer the redshift distribution of the faint blue galaxy excess (FBE) at\\u000aB=23.5 by subtracting the predicted distribution of giant\\/normal galaxies from\\u000athe observed N(z) distribution for all types. This is possible because of the\\u000arecent deep {\\\\it Hubble Space Telescope} (HST) WFPC2 morphological number\\u000acounts which have convincingly demonstrated that little evolution of the giant\\u000apopulation is seen

Simon P. Driver; Warrick J. Couch; Steven Phillipps; Rogier A. Windhorst

1996-01-01

282

Significance of absent or faint kidney sign on bone scan.  

PubMed

Seven men, six suffering from widespread bone metastases of prostatic origin and one with urinary bladder carcinoma, demonstrated minimal or no discernible radioactivity in the kidneys and urinary bladder at the time of bone scanning using 99mTc-stannous polyphosphate. The mechanism behind this scan finding is thought to be rapid and enhanced uptake of the radiopharmaceutical by pathologic bone. The significance of the faint or absent kidney sign in bone scanning, particularly in cases where abnormally homogeneous and symmetric radioactivity exists, is discussed. PMID:1159496

Sy, W M; Patel, D; Faunce, H

1975-06-01

283

Discovery of a Faint Old Stellar System at 150 kpc  

Microsoft Academic Search

We report the detection of a faint old stellar system at (alpha, delta)=(194.29d, 34.32d) (SDSS J1257+3419), based on the spatial distribution of bright red giant branch stars in the Sloan Digital Sky Survey Data Release 4. SDSS J1257+3419 has a half-light radius of 38+\\/-12 pc and an absolute integrated V magnitude of MV=-4.8+1.4-1.0 mag at a heliocentric distance of 150+\\/-15

T. Sakamoto; T. Hasegawa

2006-01-01

284

On the Poisson Approximation to Photon Distribution for Faint Lasers  

E-print Network

It is proved, that for a certain kind of input distribution, the strongly binomially attenuated photon number distribution can well be approximated by a Poisson distribution. This explains why we can adopt poissonian distribution as the photon number statistics for faint lasers. The error of such an approximation is quantitatively estimated. Numerical tests are carried out, which coincide with our theoretical estimations. This work lays a sound mathematical foundation for the well-known intuitive idea which has been widely used in quantum cryptography.

Yucheng Hu; Xiang Peng; Tiejun Li; Hong Guo

2006-09-23

285

Star Formation Rate and Extinction in Faint z ~ 4 Lyman Break Galaxies  

NASA Astrophysics Data System (ADS)

We present a statistical detection of 1.5 GHz radio continuum emission from a sample of faint z ~ 4 Lyman break galaxies (LBGs). To constrain their extinction and intrinsic star formation rate (SFR), we combine the latest ultradeep Very Large Array 1.5 GHz radio image and the Hubble Space Telescope Advanced Camera for Surveys (ACS) optical images in the GOODS-N. We select a large sample of 1771 z ~ 4 LBGs from the ACS catalog using B F435W-dropout color criteria. Our LBG samples have I F775W ~ 25-28 (AB), ~0-3 mag fainter than M^\\star _UV at z ~ 4. In our stacked radio images, we find the LBGs to be point-like under our 2'' angular resolution. We measure their mean 1.5 GHz flux by stacking the measurements on the individual objects. We achieve a statistical detection of S 1.5 GHz = 0.210 ± 0.075 ?Jy at ~3? for the first time on such a faint LBG population at z ~ 4. The measurement takes into account the effects of source size and blending of multiple objects. The detection is visually confirmed by stacking the radio images of the LBGs, and the uncertainty is quantified with Monte Carlo simulations on the radio image. The stacked radio flux corresponds to an obscured SFR of 16.0 ± 5.7 M ? yr-1, and implies a rest-frame UV extinction correction factor of 3.8. This extinction correction is in excellent agreement with that derived from the observed UV continuum spectral slope, using the local calibration of Meurer et al. This result supports the use of the local calibration on high-redshift LBGs to derive the extinction correction and SFR, and also disfavors a steep reddening curve such as that of the Small Magellanic Cloud.

To, Chun-Hao; Wang, Wei-Hao; Owen, Frazer N.

2014-09-01

286

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

287

MULTIPLE BEAM COMBINATION FOR FAINT OBJECTS E. Ribak ,G. Perrin, S. Lacour  

E-print Network

. Wynne, Opt. Comm. 28, 21-5 ,1979, C. Roddier et al., J. Optics 11. 149-52, 1980). Intermittent crown, for aperture masking on big telescopes: many beams are brought non-redundantly onto a two-dimensional detector

Ribak, Erez

288

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

289

FAINT FUZZY STAR CLUSTERS IN NGC 1023 AS REMNANTS OF MERGED STAR CLUSTER COMPLEXES  

SciTech Connect

In the lenticular galaxy NGC 1023 a third population of globular clusters (GCs), called faint fuzzies (FFs), was discovered next to the blue and red GC populations by Larsen and Brodie. While these FFs have colors comparable to the red population, the new population is fainter, larger (R{sub eff}>7 pc) and, most importantly, shows clear signs of corotation with the galactic disk of NGC 1023. We present N-body simulations verifying the hypothesis that these disk-associated FFs are related to the young massive cluster complexes (CCs) observed by Bastian et al. in M51, who discovered a mass-radius relation for these CCs. Our models have an initial configuration based on the observations from M51 and are placed on various orbits in a galactic potential derived for NGC 1023. All computations end up with a stable object containing 10%-60% of the initial CC mass after an integration time of 5 Gyr. A conversion to visual magnitudes demonstrates that the resulting objects cover exactly the observed range for FFs. Moreover, the simulated objects show projected half-mass radii between 3.6 and 13.4 pc, in good agreement with the observed FF sizes. We conclude that objects like the young massive CCs in M51 are likely progenitors of the FFs observed in NGC 1023.

Bruens, R. C.; Kroupa, P. [Argelander Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Fellhauer, M. [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)], E-mail: rcbruens@astro.uni-bonn.de, E-mail: pavel@astro.uni-bonn.de, E-mail: mfellhauer@astro-udec.cl

2009-09-10

290

The inferred redshift distribution of the faint blue excess  

E-print Network

We infer the redshift distribution of the faint blue galaxy excess (FBE) at B=23.5 by subtracting the predicted distribution of giant/normal galaxies from the observed N(z) distribution for all types. This is possible because of the recent deep {\\it Hubble Space Telescope} (HST) WFPC2 morphological number counts which have convincingly demonstrated that little evolution of the giant population is seen to B=26.0. The mean redshift of the FBE at B=23.5 is found to be _{FBE}=0.40 +/- 0.07 with upper and lower quartiles defined by z_{0.75}=0.58 +/- 0.05 and z_{0.25}=0.28 +/- 0.05, respectively. We compare this inferred FBE N(z) distribution to the predictions from three generic faint galaxy models: dwarf dominated (no evolution), pure luminosity evolution, and evolving dwarfs. The inferred FBE N(z) distribution strongly supports a hybrid evolving dwarf--rich model wherein a large population of dwarfs present at z=0.5 has subsequently faded to obscurity. The total integrated number density of dwarfs (down to M_{B}...

Driver, S P; Phillipps, S; Windhorst, R A; Driver, Simon P; Couch, Warrick J; Phillipps, Steven; Windhorst, Rogier A

1996-01-01

291

The inferred redshift distribution of the faint blue excess  

E-print Network

We infer the redshift distribution of the faint blue galaxy excess (FBE) at B=23.5 by subtracting the predicted distribution of giant/normal galaxies from the observed N(z) distribution for all types. This is possible because of the recent deep {\\it Hubble Space Telescope} (HST) WFPC2 morphological number counts which have convincingly demonstrated that little evolution of the giant population is seen to B=26.0. The mean redshift of the FBE at B=23.5 is found to be _{FBE}=0.40 +/- 0.07 with upper and lower quartiles defined by z_{0.75}=0.58 +/- 0.05 and z_{0.25}=0.28 +/- 0.05, respectively. We compare this inferred FBE N(z) distribution to the predictions from three generic faint galaxy models: dwarf dominated (no evolution), pure luminosity evolution, and evolving dwarfs. The inferred FBE N(z) distribution strongly supports a hybrid evolving dwarf--rich model wherein a large population of dwarfs present at z=0.5 has subsequently faded to obscurity. The total integrated number density of dwarfs (down to M_{B}=-11) is estimated to be a factor of 20 times greater than that of E---Sc galaxies and the estimated fading to be 1.0 < \\Delta m < 1.4 mags. Thus, the dwarf population is estimated to be responsible for ~30% of the luminosity density locally, rising to ~57% at z=0.5.

Simon P. Driver; Warrick J. Couch; Steven Phillipps; Rogier A. Windhorst

1996-05-10

292

Disgust, anxiety and fainting symptoms associated with blood-injection-injury fears: a structural model.  

PubMed

The present study examines the structural relations between disgust sensitivity, anxiety symptoms, blood-injection-injury (BII) fears, and fainting symptoms associated with BII fears in 259 nonclinical participants. Results revealed that both disgust and BII fear were independent predictors of fainting symptoms. However, structural equation modeling revealed that the relation between disgust sensitivity and fainting was reduced to negative and non-significance when the path from BII fear to fainting was also introduced. Subsequent analysis indicated that the relation between disgust sensitivity and fainting symptoms was fully mediated by BII fear. It was also found that animal reminder disgust was related to fainting symptoms whereas core disgust was not. However, the relation between animal reminder disgust and fainting was also fully mediated by BII fear. Furthermore, anxiety symptoms did not add directly to the structural model predicting fainting associated with BII fears. Implications of these findings for better understanding the interaction of the emotional mechanisms that mediate fainting responses in BII phobia are discussed. PMID:16325112

Olatunji, Bunmi O; Williams, Nathan L; Sawchuk, Craig N; Lohr, Jeffrey M

2006-01-01

293

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

294

Near-infrared Thermal Emission Detections of a Number of Hot Jupiters and the Systematics of Ground-based Near-infrared Photometry  

NASA Astrophysics Data System (ADS)

We present detections of the near-infrared thermal emission of three hot Jupiters and one brown dwarf using the Wide-field Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT). These include Ks-band secondary eclipse detections of the hot Jupiters WASP-3b and Qatar-1b and the brown dwarf KELT-1b. We also report Y-band, K CONT-band, and two new and one reanalyzed Ks-band detections of the thermal emission of the hot Jupiter WASP-12b. We present a new reduction pipeline for CFHT/WIRCam data, which is optimized for high precision photometry. We also describe novel techniques for constraining systematic errors in ground-based near-infrared photometry, so as to return reliable secondary eclipse depths and uncertainties. We discuss the noise properties of our ground-based photometry for wavelengths spanning the near-infrared (the YJHK bands), for faint and bright stars, and for the same object on several occasions. For the hot Jupiters WASP-3b and WASP-12b we demonstrate the repeatability of our eclipse depth measurements in the Ks band; we therefore place stringent limits on the systematics of ground-based, near-infrared photometry, and also rule out violent weather changes in the deep, high pressure atmospheres of these two hot Jupiters at the epochs of our observations. Based on observations obtained with WIRCam, a joint project of Canada-France-Hawaii Telescope (CFHT), Taiwan, Korea, Canada, France, at the CFHT, which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

Croll, Bryce; Albert, Loic; Jayawardhana, Ray; Cushing, Michael; Moutou, Claire; Lafreniere, David; Johnson, John Asher; Bonomo, Aldo S.; Deleuil, Magali; Fortney, Jonathan

2015-03-01

295

Measuring the orbital history of the ultra-faint dwarf galaxy Hercules with GSAOI  

NASA Astrophysics Data System (ADS)

The Milky Way ultra-faint dwarf galaxies are the most dark matter dominated systems known to date. Their low masses, low luminosities, and extremely low metallicities offer a glimpse into galaxy formation at the earliest epochs, while their high inferred dark matter densities and proximity make them ideal candidates for indirect dark matter detection experiments. However, significant uncertainties remain in key observables such as the mass and infall history of these extreme objects. For example, without knowledge of their orbits, it is difficult to determine whether their masses are overestimated because their radial velocity dispersions have been inflated by past tidal encounters with the Milky Way. We propose to measure the proper motion of the Hercules ultra-faint dwarf galaxy using GSAOI to understand its orbital history. Hercules is a particularly intriguing target because structural and kinematic studies have motivated claims that it is tidally disrupting despite its relatively large present distance from the Milky Way and apparently high mass-to-light ratio. It also has a very old stellar population, making it a prime candidate for a "fossil galaxy" whose star formation was shut off by reionization. With observations in 2014A, 2015A, and 2017A in conjunction with HST data taken in 2011, we will be able to achieve 35 km/s proper motion precision, making it possible to reconstruct the orbit of Hercules. Knowledge of its perigalacticon will allow us to quantify the tidal effects of the Milky Way on its internal stellar dynamics, while its eccentricities and orbital energies will constrain the initial infall time into the Milky Way dark matter halo. This proposal aims to extend the technique developed of HST data to using background galaxies as absolute reference sources to ground based MCAO observations, which will be important for astrometry work after HST and for future extremely large telescopes.

Do, Tuan; Lu, Jessica; Simon, Josh; Peter, Annika; Boylan-Kolchin, Mike

2014-02-01

296

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

297

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

298

Adaptive Optics Imaging Survey of Luminous Infrared Galaxies  

SciTech Connect

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{sub FIR} {ge} 10{sup 12} L{sub {circle_dot}}) and 19 new LIGs (with L{sub FIR} {ge} 10{sup 11} L{sub {circle_dot}}). Twenty of the galaxies in the sample were imaged with either the Lick or Keck adaptive optics systems in H or K{prime}. 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.

Laag, E A; Canalizo, G; van Breugel, W; Gates, E L; de Vries, W; Stanford, S A

2006-03-13

299

Infrared SETI  

Microsoft Academic Search

SETI at infrared wavelengths is discussed, and relative advantages or disadvantages of searches at various wavelengths, including microwave SETI, are analyzed. The mid-infrared appears to be one of the most favorable regions for a SETI.

Charles H. Townes

1993-01-01

300

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

301

The Inferred Redshift Distribution of the Faint Blue Galaxy Excess  

NASA Astrophysics Data System (ADS)

We infer the redshift distribution of the faint blue galaxy excess (FBE) at mB = 23.5 by subtracting the predicted distribution of giant/normal galaxies from the observed N(z) distribution for all types. This is possible because of the recent deep Hubble Space Telescope (HST) WFPC2 morphological number counts that have convincingly demonstrated that little evolution of the giant population is seen to mB = 26.0. The mean redshift of the FBE at mB = 23.5 is found to be FBE = 0.40 +/- 0.07 with upper and lower quartiles defined by z0.75 = 0.58 +/- 0.05 and z0.25 = 0.28 +/- 0.05, respectively. We compare this inferred FBE N(z) distribution to the predictions from three generic faint galaxy models: dwarf dominated (no-evolution), pure luminosity evolution, and evolving dwarfs. The inferred FBE N(z) distribution strongly supports a hybrid evolving dwarf--rich model wherein a large population of dwarfs present at z = 0.5 has subsequently faded to obscurity. The total integrated number density of dwarfs (down to MB = -11) is estimated to be a factor of 20 times greater than that of E--Sc galaxies and the estimated fading to be 1.0 < Delta m < 1.4 mag. Thus, the dwarf population is estimated to be responsible for ~30% of the luminosity density locally, rising to ~57% at z = 0.5.

Driver, Simon P.; Couch, Warrick J.; Phillipps, Steven; Windhorst, Rogier A.

1996-07-01

302

GRB 051028: an intrinsically faint GRB at high redshift?  

E-print Network

We present multiwavelength observations of the gamma-ray burst GRB 051028 detected by HETE-2 in order to derive its afterglow emission parameters and to determine the reason for its optical faintness when compared to other events. Observations were taken in the optical (2.0m Himalayan Chandra Telescope, 1.34m Tautenburg, 4.2m William Herschel Telescope) and in X-rays (Swift/XRT) between 2.7 hours and 10 days after the onset of the event. The data can be interpreted by collimated emission in a jet with a typical value of $p$ = 2.4 which is moving in an homogeneous interstellar medium and with a cooling frequency nu_{c} still above the X-rays at 0.5 days after the burst onset. GRB 051028 can be classified as a ``gray'' or ``potentially dark'' GRB. On the basis of the combined optical and Swift/XRT data, we conclude that the reason for the optical dimness is not extra absorption in the host galaxy, but rather the GRB taking place at high-redshift.We also notice the very striking similarity with the optical lightcurve of GRB 050730, a burst with a spectroscopic redshift of 3.967, although GRB 051028 is about 3 mag fainter. We suggest that the bump could be explained by multiple energy injection episodes and that the burst is intrinsically faint when compared to the average afterglows detected since 1997. The non-detection of the host galaxy down to R = 25.1 is also consistent with the burst arising at high redshift, compatible with the published pseudo-z of 3.7 +/- 1.8.

A. J. Castro-Tirado; M. Jelinek; S. B. Pandey; S. McBreen; J. de Jong; D. K. Sahu; P. Ferrero; J. A. Caballero; J. Gorosabel; D. A. Kann; S. Klose; A. de Ugarte Postigo; G. C. Anupama; C. Gry; S. Guziy; S. Srividya; L. Valdivielso; S. Vanniarajan; A. A. Henden

2006-09-24

303

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

304

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

305

The Faint Young Sun Piet Martens Harvard-Smithsonian Center for  

E-print Network

to the planets therefore goes as S ~ M 6 #12;Estimated mass loss rate vs. stellar age Wood et al. (2002) Sun #12The Faint Young Sun Paradox Piet Martens ­ Harvard-Smithsonian Center for Astrophysics & Montana), John Priscu (MSU) #12;The Faint Young Sun Paradox The Sun was about 30% less luminous when life

Martens, Petrus C.

306

Searching for managerial opportunism in diversifying acquisitions... Searching for faint traces of managerial opportunism in  

E-print Network

Searching for managerial opportunism in diversifying acquisitions... 1 Searching for faint traces of managerial opportunism in french diversifying acquisitions Frédéric Perdreau CREREG-Axe Finance Faculté de in diversifying acquisitions... 2 Searching for faint traces of managerial opportunism in french diversifying

Paris-Sud XI, Université de

307

The role of disgust in faintness elicited by blood and injection stimuli.  

PubMed

To examine the role of disgust in blood-injection fear and faintness, 79 individuals high and low in disgust and distressed either more by blood or injections were exposed to both a blood slide and a needle slide. Self-reported faintness and systolic and diastolic blood pressure were measured. High disgust individuals reported more faintness to both slides, but those who were more distressed by blood reported more faintness to the blood slide and those who were more distressed by needles reported more fear to the needle slide. Both systolic and diastolic blood pressure assessments manifested a diphasic response. The diphasic response pattern was most evident among the high disgust subjects, who were more distressed by blood than injections. Results are discussed in terms of the relevance of disgust in the etiology of fear and faintness in blood-injury phobia. PMID:12464288

Page, Andrew C

2003-01-01

308

Confirmation of two extended objects along the line of sight to PKS1830-211 with ESO-VLT adaptive optics imaging  

E-print Network

We report on new high-resolution near-infrared images of the gravitationally lensed radio source PKS1830-211, a quasar at z=2.507. These adaptive optics observations, taken with the Very Large Telescope (VLT), are further improved through image deconvolution. They confirm the presence of a second object along the line of sight to the quasar, in addition to the previously known spiral galaxy. This additional object is clearly extended in our images. However, its faint luminosity does not allow to infer any photometric redshift. If this galaxy is located in the foreground of PKS1830-211, it complicates the modeling of this system and decreases the interest in using PKS1830-211 as a means to determine H0 via the time delay between the two lensed images of the quasar.

G. Meylan; F. Courbin; C. Lidman; J. -P. Kneib; L. E. Tacconi-Garman

2005-06-27

309

Searching Faint and Extended Sources in the X-ray Universe  

NASA Astrophysics Data System (ADS)

A Bayesian mixture modeling method was applied to Chandra Deep Field South (CDF-S) to find faint extended sources at high redshift. The probabilistic two-component mixture model allows the separation of the diffuse background from celestial sources within a one-step algorithm without data censoring. The background is modeled with a thin-plate spline.The source and background estimation method was extended to allow the flux of celestial objects to be inverse-Gamma distributed. In addition, all the detected sources are automatically parameterized to produce a list of source positions, count rates and morphological parameters. The present analysis is applied to the CDF-S. With its 940 ksec of exposure time, CDF-S is one of the deepest X-ray observations performed. We analyze the 0.5-2 keV energy band to search for clusters or groups of galaxies. Point-like and extended sources are separated incorporating the knowledge of the observatory's point spread function (PSF). Combining the Bayesian mixture modeling technique with the angular resolution (~= 1 arcsec) of the CDF-S data, we can provide information about rare objects, such as clusters of galaxies, in the distant Universe.

Guglielmetti, Fabrizia; Fischer, Rainer; Rosati, Piero; Mainieri, Vincenzo; Dose, Volker

2005-11-01

310

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.

311

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

NASA Astrophysics Data System (ADS)

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

Chattopadhyay, Tanuka; Karmakar, Pradip

2013-08-01

312

Observations of Near-Earth Asteroid 2010 CN141 with the Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

The near-Earth asteroid 2010 CN141 was discovered by NASA's Wide-Field Infrared Survey Explorer (WISE) in February 2010, with follow-up observations from Mauna Kea by M. Micheli, G. T. Elliott, and D. J. Tholen from February to April. 2010 CN141's low visual albedo and its proximity to Earth caught the attention of observers, and it was selected for more detailed analysis. Its orbit brought it back into WISE's field of view in May, though it was near WISE's detection limit, and it was uncertain whether the asteroid would actually be visible. Subsequent analysis of the relevant WISE frames revealed a faint spot inside the error ellipse that was probably but not conclusively 2010 CN141. The spot was about three arcseconds from the asteroid's expected position. An independent observation from Mauna Kea in April also found a faint object, which was likely 2010 CN141, near the expected coordinates. Thermal modeling of the February observations, using both the Standard Thermal Model (which assumes slow rotation) and the Fast-Rotating Model, indicates that the asteroid has a diameter of 287 m ± 18 m (random) ± 29 m (systematic), a visual geometric albedo of 0.0252 ± 0.0040 (random) ± 0.0051 (systematic), and a bolometric Bond albedo of 0.0099 ± 0.0016 (random) ± 0.0020 (systematic). 2010 CN141 will come relatively close to Earth in the fall of 2011, and there will be good opportunities to observe it for several months.

Marshall, Sean; Wright, E. L.

2011-01-01

313

Toward 10-milliarcsecond infrared astrometry  

Microsoft Academic Search

Infrared astrometry at the 10-milliarcsecond (mas) level is applicable to experiments in stellar evolution astronomy, solar system dynamics, relativistic gravitation, and deep space laser tracking. We are pursing astrometry with the U. C. Berkeley Infrared Spatial Interferometer (ISI) on Mt. Wilson to demonstrate a 10-mas capability for tracking stellar and solar system objects. Astrometric data from the ISI, taken and

Robert N. Treuhaft; Stephen T. Lowe; Manfred Bester; William C. Danchi; Charles H. Townes

1994-01-01

314

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

315

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

316

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

317

Helium shells and faint emission lines from slitless flash spectra.  

PubMed

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. PMID:25685435

Bazin, Cyril; Koutchmy, Serge

2013-05-01

318

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. PMID:25685435

Bazin, Cyril; Koutchmy, Serge

2013-01-01

319

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

320

Outflows from Luminous YSOs: An Infrared Polarimetric Study  

E-print Network

e present Near Infrared imaging polarimetry of three regions of massive star formation, G$192.16 - 3.82$, Cepheus A, and W42. In W42 we have discovered a new bipolar nebula located at the far side of the HII region behind the visible cluster of exciting stars. The axis of this new nebula is aligned with the magnetic field threading the entire cluster region. Polarization in the bipolar outflow nebulosity associated with G192.16 is consistent with a single illuminating source, too faint to be detected at $2 \\micron$. Polarization in the reflection nebulosity associated with Ceph A requires more than one illuminating source, although HW2 is clearly dominant. In all three objects, the magnetic field in the outflow at distances greater than $\\sim 0.2$ pc is radial. In G192.16 the magnetic field geometry closer than $\\sim 0.2$ pc to the embedded star appears chaotic. For G192.16 the outflow is not aligned with the surrounding magnetic field, which lies in the galactic plane. In Ceph A, the outflow axis could be interpreted as being aligned with the galactic plane, but the magnetic field threading the region is not. Only in the case of W42 is the magnetic field threading the HII region aligned with the mean field in the surrounding galactic plane.

Terry J. Jones; Charles E. Woodward; Michael S. Kelley

2004-07-21

321

Infrared spectral classification of normal stars  

Microsoft Academic Search

Moderate resolution (~400) 2.38-45.2 mu m infrared spectra of stars without dust features were obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). The observations are part of a larger program with the objective to extend and refine the current infrared classification schemes. In particular, our data provide the basis for a more detailed classification

A. M. Heras; R. F. Shipman; S. D. Price; Th. de Graauw; H. J. Walker; M. Jourdain de Muizon; M. F. Kessler; T. Prusti; L. Decin; B. Vandenbussche; L. B. F. M. Waters

2002-01-01

322

Infrared Thermometers  

NSDL National Science Digital Library

An infrared (IR) thermometer lab offers the opportunity to give science students a chance to measure surface temperatures, utilizing off-the-shelf-technology. Students will enjoy this inquiry-based activity as they use infrared thermometers to examine various materials, metals, color surfaces, and textures on a car.

John Schaefers

2006-01-01

323

The Quenching of the Ultra-faint Dwarf Galaxies in the Reionization Era  

NASA Astrophysics Data System (ADS)

We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our analysis employs a combination of high-precision photometry obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, medium-resolution spectroscopy obtained with the DEep Imaging Multi-Object Spectrograph on the W. M. Keck Observatory, and updated Victoria-Regina isochrones tailored to the abundance patterns appropriate for these galaxies. The data for five of these Milky Way satellites are best fit by a star formation history where at least 75% of the stars formed by z ~ 10 (13.3 Gyr ago). All of the galaxies are consistent with 80% of the stars forming by z ~ 6 (12.8 Gyr ago) and 100% of the stars forming by z ~ 3 (11.6 Gyr ago). The similarly ancient populations of these galaxies support the hypothesis that star formation in the smallest dark-matter sub-halos was suppressed by a global outside influence, such as the reionization of the universe. Based on observations made 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. These observations are associated with program GO-12549.

Brown, Thomas M.; Tumlinson, Jason; Geha, Marla; Simon, Joshua D.; Vargas, Luis C.; VandenBerg, Don A.; Kirby, Evan N.; Kalirai, Jason S.; Avila, Roberto J.; Gennaro, Mario; Ferguson, Henry C.; Muñoz, Ricardo R.; Guhathakurta, Puragra; Renzini, Alvio

2014-12-01

324

A Hero's Dark Horse: Discovery of an Ultra-Faint Milky Way Satellite in Pegasus  

E-print Network

We report the discovery of an ultra-faint Milky Way satellite galaxy in the constellation of Pegasus. The concentration of stars was detected by applying our overdensity detection algorithm to the SDSS-DR 10 and confirmed with deeper photometry from the Dark Energy Camera at the 4-m Blanco telescope. Fitting model isochrones indicates that this object, Pegasus III, features an old and metal-poor stellar population ([Fe/H]$\\sim-2.1$) at a heliocentric distance of $205\\pm20$ kpc. The new stellar system has an estimated half-light radius of $r_h=110\\pm6$ pc and a total luminosity of $M_{V}\\sim-4.1\\pm0.5$ that places it into the domain of dwarf galaxies on the size--luminosity plane. Pegasus III is spatially close to the MW satellite Pisces II. It is possible that the two might be physically associated, similar to the Leo IV and Leo V pair. Pegasus III is also well aligned with the Vast Polar Structure, which suggests a possible physical association.

Kim, Dongwon; Mackey, Dougal; Da Costa, Gary S; Milone, Antonino P

2015-01-01

325

Faint Cataclysmic Variables in Quiescence: Globular Cluster and Field Surveys  

NASA Astrophysics Data System (ADS)

Current evolutionary models imply that most cataclysmic variables (CVs) have Porb<2 hr and are dwarf nova (DN) systems that are quiescent most of the time. Observations of nearby quiescent DNs find that the UV spectrum is dominated by the hot white dwarf (WD), indicating that it provides a significant fraction of the optical light in addition to the quiescent disk and main-sequence companion. Hence, identifying a faint, quiescent CV in either the field or a globular cluster (GC) from broadband colors depends on our ability to predict the WD contribution in quiescence. We are undertaking a theoretical study of the compressional heating of WDs, extending down to very low time-averaged accretion rates, ~10-11 Msolar yr-1, which allows us to self-consistently find the Teff of the WD. We demonstrate here that most of the compressional heating occurs in the freshly accreted envelope and that the WD core temperature reaches a fixed value on a timescale of less than typical evolutionary times. Since nuclear burning is unstable at these 's, we have incorporated the recurrent heating and cooling of the WD core throughout the classical novae limit cycle in order to find the Teff- relations. Comparing with observations of field DNs confirms the -Porb relation of disrupted magnetic braking. We also predict broadband colors of a quiescent CV as a function of and companion mass and show that this leads to the identification of what may be many CVs in deep Hubble Space Telescope images of GCs.

Townsley, Dean M.; Bildsten, Lars

2002-01-01

326

The Measurement and Lensing of the Faint Source Correlation Function  

NASA Astrophysics Data System (ADS)

The faint source correlation function (FSCF) has previously been a barely measured and totally unused quantity. While it had been tentatively observed down to scales of a few arcseconds in the HDF, its amplitude was on the order of 10-1. I show, using a combination of higher quality data (GOODS and UDF), superior pair-finding source extraction and extensive use of custom image simulations to counter systematics, that the FSCF is not only measurable down to scales of 0.3'' (2.6 kpc at most) but that on such short distance scales it also exceeds unity for 25 < V < 28 sources. My measurement of the FSCF as a power law with an index of -2.5 rather than the measured large-scale index of -0.7 shows that the physics of galactic-scale correlation functions is different from that of the cosmological correlation function. I also measured a reduced three point correlation function, confirming that the FSCF is non-Gaussian, and used the measurement of close pairs to set upper limits on the cosmic string density. Applications of lensing on the FSCF are most interesting. I show, theoretically, that gravitational lenses induce a local anisotropy in the FSCF that is proportional to the lensing shear. For lenses of known mass profile, we can invert the lens equation to solve for the distance to the source using the shear and the induced anisotropy. This produces a distance estimate of the faintest sources without using any spectral information. I establish the framework for using this technique with a large population of galaxy scale lenses, a single large cluster lens or a large field with cosmic shear. Large future datasets with a wide range of lens redshifts will allow us to measure this effect precisely to gain a true, non-spectral distance distribution of the faintest sources.

Morganson, Eric P.

2009-01-01

327

History of infrared detectors  

NASA Astrophysics Data System (ADS)

This paper overviews the history of infrared detector materials starting with Herschel's experiment with thermometer on February 11th, 1800. Infrared detectors are in general used to detect, image, and measure patterns of the thermal heat radiation which all objects emit. At the beginning, their development was connected with thermal detectors, such as thermocouples and bolometers, which are still used today and which are generally sensitive to all infrared wavelengths and operate at room temperature. The second kind of detectors, called the photon detectors, was mainly developed during the 20th Century to improve sensitivity and response time. These detectors have been extensively developed since the 1940's. Lead sulphide (PbS) was the first practical IR detector with sensitivity to infrared wavelengths up to ˜3 ?m. After World War II infrared detector technology development was and continues to be primarily driven by military applications. Discovery of variable band gap HgCdTe ternary alloy by Lawson and co-workers in 1959 opened a new area in IR detector technology and has provided an unprecedented degree of freedom in infrared detector design. Many of these advances were transferred to IR astronomy from Departments of Defence research. Later on civilian applications of infrared technology are frequently called "dual-use technology applications." One should point out the growing utilisation of IR technologies in the civilian sphere based on the use of new materials and technologies, as well as the noticeable price decrease in these high cost technologies. In the last four decades different types of detectors are combined with electronic readouts to make detector focal plane arrays (FPAs). Development in FPA technology has revolutionized infrared imaging. Progress in integrated circuit design and fabrication techniques has resulted in continued rapid growth in the size and performance of these solid state arrays.

Rogalski, A.

2012-09-01

328

IRTS observation of the near-infrared extragalactic background light  

E-print Network

We searched for near-infrared extragalactic background light (EBL) in the data from the Near-InfraRed Spectrometer (NIRS) on the Infrared Telescope in Space (IRTS). After subtracting the contribution of faint stars and the zodiacal component based on modeling, a significant isotropic emission is obtained in the wavelength bands from 1.4 micron to 4.0 micron. The in-band flux amounts to ~ 35 nW m-2 sr-1 which is too bright to be explained by the integrated light from faint galaxies. Significant fluctuations in sky brightness were also detected which can not be explained by fluctuations due to faint stars, zodiacal components and normal galaxies. The excess fluctuation amounts to ~ 1/4 of the excess emission over the integrated light of galaxies. A two-point correlation analysis shows that IRTS/NIRS data has an angular scale of fluctuations of a few degrees. Recent WMAP results of CMB polarization indicate that the reionization of the Universe occurred at z ~ 17 or earlier. The observed near infrared background light could be redshifted UV light from the first generation of massive stars (Pop.III stars) which caused the reionization of the Universe. The spectral jump around 1 micron over the optical EBL suggests that massive star formation terminated at z~9. The observed fluctuations, however, are considerably larger than the theoretical predictions and require a new scenario for the Pop.III era.

T. Matsumoto; S. Matsuura; H. Murakami; M. Tanaka; M. Freund; M. Lim; M. Cohen; M. Kawada; M. Noda

2005-03-04

329

A measurement of the faint source correlation function in the GOODS and UDF surveys  

Microsoft Academic Search

We present a stable procedure for defining and measuring the two point angular autocorrelation function, w(theta) = [theta\\/theta0(V)]-Gamma, of faint (25 < V < 29), barely resolved and unresolved sources in the Hubble Space Telescope Great Observatories Origins Deep Survey and Ultra Deep Field data sets. We construct catalogues that include close pairs and faint detections. We show, for the

Eric Morganson; Roger Blandford

2009-01-01

330

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

331

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

332

Cryogenic far-infrared detectors for the Space Infrared Interferometric Telescope (SPIRIT)  

NASA Astrophysics Data System (ADS)

SPIRIT is a spatial and spectral interferometer with an operating wavelength range 25 ?m - 400 ?m. As a double-Fourier interferometer, SPIRIT features sub-arcsecond spatial resolution and R??/??=3000 spectral resolution over a 1 arcmin field of view. Its three primary scientific objectives are to: (1) Learn how planetary systems form from protostellar disks, and how they acquire their chemical organization; (2) Characterize the family of extrasolar planetary systems by imaging the structure in debris disks to understand how and where planets form, and why some planets are ice giants and others are rocky; and (3) Learn how high-redshift galaxies formed and merged to form the present-day population of galaxies. The detector subsystem provides a set of far-infrared detector arrays in the SPIRIT instrument. These arrays are used for science purposes by detecting the faint interferometric signal. The resulting technology requirement is for a set of eight arrays operating at wavelengths of 25 ?m - 400 ?m, divided into two arrays (one for each interferometer output port) per octave of wavelength. At the short wavelength end, the arrays are 14×14 pixels, shrinking to 2×2 at the longest band. The per-pixel sensitivity requirement of 10 -19 W/?Hz, coupled with speed of ? effective ~150 ?s, make these relatively small arrays challenging. The operating temperature necessary to provide this sensitivity is around 50 mK. Over the majority of the SPIRIT wavelength range and sensitivity requirement, there are no commercial vendors of such detector arrays, and thus they will require a separate NASA-supported development.

Benford, Dominic J.; Rinehart, Stephen A.; Leisawitz, David T.; Hyde, T. Tupper

2007-09-01

333

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

334

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

335

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

336

THE AROMATIC FEATURES IN VERY FAINT DWARF GALAXIES  

SciTech Connect

We present optical and mid-infrared photometry of a statistically complete sample of 29 dwarf galaxies (M{sub r} > - 15 mag) selected from the Sloan Digital Sky Survey (SDSS) spectroscopic sample and observed in the mid-infrared with Spitzer IRAC. This sample contains nearby (redshift {approx}<0.005) galaxies 3 mag fainter than previously studied samples. We compare our sample with other star-forming galaxies that have been observed with both IRAC and SDSS. We examine the relationship of the infrared color, [3.6]-[7.8], sensitive to polycyclic aromatic hydrocarbon (PAH) abundance and also hot dust and stellar continuum, with star formation rates (SFRs), oxygen abundances, and radiation hardness, all estimated by optical emission lines. Consistent with studies of more luminous dwarfs, we find that these dwarf galaxies show much redder [3.6]-[7.8] color than luminous galaxies with similar specific SFRs. Unlike luminous galaxies, we find that these dwarf galaxies show no significant dependence at all of the [3.6]-[7.8] color on SFR, oxygen abundance, or radiation hardness, despite the fact that the sample spans a significant range in all of these quantities. When the dwarfs in our sample are compared with more luminous dwarfs, we find that the [3.6]-[7.8] color, potentially tracing the PAH emission, depends on oxygen abundance and radiation hardness. However, these two parameters are correlated with one another as well; we break this degeneracy by looking at the PAH-oxygen abundance relation at a fixed radiation hardness and the PAH-hardness relation at a fixed oxygen abundance. This test shows that the [3.6]-[7.8] color in dwarf galaxies appears to depend more directly on oxygen abundance based on the data currently available.

Wu Ronin; Hogg, David W.; Moustakas, John [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)

2011-04-01

337

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

338

Seeing Infrared.  

ERIC Educational Resources Information Center

Provides directions for building a comparatively inexpensive device that detects and displays images of infrared light sources. Includes typical costs for the components, an artist's sketch of the finished product, and suggestions for adjustments and image recordings. (JJK)

Mooney, Donald

1992-01-01

339

Searching for Faint Exozodiacal Disks: Keck Results and LBTI Status  

NASA Astrophysics Data System (ADS)

The possible presence of dust in the habitable zone around nearby main-sequence stars is considered as a major hurdle toward the direct imaging of Earth-like extrasolar planets with future dedicated space-based telescopes (e.g., Roberge et al. 2012). In this context, NASA has funded two ground-based mid-infrared nulling interferometers to combine the large apertures available at the Keck Observatory and the Large Binocular Telescope (LBT). In this poster, we present the preliminary results of the extended survey carried out with the Keck Interferometer Nuller (KIN) between 2008 and 2011 and describe the forthcoming LBTI survey.

Defrère, D.; Hinz, P.; Mennesson, B.; Millan-Gabet, R.; Skemer, A.; Bailey, V.; Rodigas, T. J.

2014-01-01

340

The Design of a Novel Survey for Small Objects in the Solar System  

Microsoft Academic Search

We evaluated several concepts for a new survey for small objects in the Solar System. We designed a highly novel survey for comets in the outer region of the Solar System, which exploits the occultations of relatively bright stars to infer the presence of otherwise extremely faint objects. The populations and distributions of these objects are not known; the uncertainties

C. Alcock; W. P. Chen; I. de Pater; T. Lee; J. Lissauer; J. Rice; C. Liang; K. Cook; S. Marshall; C. Akerlof

2000-01-01

341

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.

342

Adaptive optics for high-contrast imaging of faint substellar companions  

NASA Astrophysics Data System (ADS)

Direct imaging of faint objects around bright stars is challenging because the primary star's diffracted light can overwhelm low-mass companions. Nevertheless, advances in adaptive optics (AO) and high-contrast imaging have revealed the first pictures of extrasolar planets. In this dissertation I employ today's high-contrast AO techniques to image brown dwarfs around stars in the nearby Hyades cluster. Furthermore, I prepare for the next generation of high-contrast AO instrumentation, by qualifying MEMS deformable mirrors for wavefront control in the Gemini Planet Imager. In Part I, I present discovery of 3 new brown dwarfs and 36 low-mass stellar companions to 85 stars in the Hyades, imaged with AO at Keck and Lick Observatories. The "locally-optimized combination of images" (LOCI) image-diversity technique filters out the primary star to reveal faint companions. This survey is complete to the hydrogen-burning limit at separations beyond 20 AU. In the complete sample, multiplicity increases as primary star mass decreases. Additionally, the brown dwarfs are at wide >150 AU separations. Finding this preference for low binding-energy systems is an unexpected result, as the Hyades is 625 Myr old and dynamically relaxed. Future work will continue to explore this trend to understand the dynamical and star formation history of the Hyades. The brown dwarfs are near interesting transition regimes for low-mass objects; therefore, characterizing their atmospheres with spectrophotometry will serve as an important benchmark for our understanding of these cool objects. In Part II, I demonstrate micro-electro-mechanical systems (MEMS) deformable mirrors for high-order wavefront control in the Gemini Planet Imager (GPI). MEMS micromirrors have thousands of degrees of freedom and represent a significant cost efficiency over conventional glass deformable mirrors, making them ideal for high-contrast AO. In Chapter 7, I present experimental evidence that MEMS actuators function well and are stable and repeatable at the sub-nm level over the course of an hour. In Chapter 8, I prove MEMS ability to correct high-order Kolmogorov turbulence and maintain the high-contrast "dark hole" in the GPI woofer-tweeter architecture. Finally, in Chapter 9, I analyze MEMS performance on sky with Villages, a telescope testbed for MEMS technology, visible-light AO, and open-loop control. The MEMS remains repeatably flat and controllable over ˜4 years and ˜800 hours of operation. Open loop control of the hysteresis-free MEMS produces a diffraction-limited core in I-band, while internal static errors dominate the on-sky error budget. This work establishes MEMS deformable mirrors as excellent wavefront correctors for high-order AO. The MEMS in GPI will produce a deeper, broader dark hole, allowing for detection and characterization of directly-imaged planets in a fainter, wider search space.

Morzinski, Katie M.

343

An infrared study of local galaxy mergers  

E-print Network

We combine a large, homogeneous sample of $\\sim$3000 local mergers with the Imperial IRAS Faint Source Redshift Catalogue (IIFSCz), to perform a blind far-infrared (FIR) study of the local merger population. The IRAS-detected mergers are mostly ($98\\%$) spiral-spiral systems, residing in low density environments, a median FIR luminosity of $10^{11} L_\\odot$ (which translates to a median star formation rate of around 15$M_\\odot yr^{-1}$). The FIR luminosity -- and therefore the star formation rate -- shows little correlation with group richness and scales with the total stellar mass of the system, with little or no dependence on the merger mass ratio. In particular, minor mergers (mass ratios $galaxies ($65\\%$ of our LIRGs are minor mergers), with some minor-merging systems being close to the ultra luminous infrared galaxy (ULIRG) limit. Optical emi...

Carpineti, Alfredo; Hyde, Ashley K; Clements, David L; Schawinski, Kevin; Darg, Daniel; Lintott, Chris J

2015-01-01

344

Ground based infrared astronomy  

NASA Technical Reports Server (NTRS)

Infrared spectroscopic instrumentation has been developed for ground-based measurements of astrophysical objects in the intermediate infrared. A conventional Michelson interferometer is limited for astronomical applications in the intermediate infrared by quantum noise fluctuations in the radiation form the source and/or background incident on the detector, and the multiplex advantage is no longer available. One feasible approach to recovering the multiplex advantage is post-dispersion. The infrared signal after passing through telescope and interferometer, is dispersed by a low resolution grating spectrometer onto an array of detectors. The feasibility of the post-dispersion system has been demonstrated with observations of astrophysical objects in the 5 and 10 micrometer atmospheric windows from ground-based telescopes. During FY87/88 the post-disperser was used at the Kitt Peak 4-meter telescope and McMath telescope with facility Fourier transform spectrometers. Jupiter, Saturn, Mars, and Venus were observed. On Jupiter, the resolution at 12 micrometer was 0.01/cm, considerably higher than had been acheived previously. The spectrum contains Jovian ethane and acetylene emission. Construction was begun on the large cryogenic grating spectrometer.

Jennings, D. E.

1988-01-01

345

1-cm collimated source for use in infrared calibrations  

Microsoft Academic Search

Collimated infrared sources covering the 2 micrometer to 30 micrometer range of wavelengths are necessary to simulate infrared radiation from distant objects. This is important because on-orbit servo and tracking systems make extensive use of infrared radiation for remote sensing. Collimators are used to calibrate infrared detectors in terms of absolute power within a given spectral range. The National Institute

Beverly J. Klemme; Timothy M. Jung; Adriaan C. Carter; Eric L. Shirley; Steven R. Lorentz; Raju V. Datla

2000-01-01

346

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

347

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

348

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

349

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.

350

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

351

Exozodiacal discs with ALADDIN: how faint can we detect them?  

NASA Astrophysics Data System (ADS)

In this paper, we describe the expected performance of ALADDIN, a nulling interferometer project optimised for operation at Dome C. After reviewing the main atmospheric parameters pertaining to infrared interferometry on the high Antarctic plateau, we shortly describe the ALADDIN instrument and compute its estimated performance in terms of the smallest exozodiacal dust disc density that can be detected. Our estimations are based on a thorough end-to-end software simulator previously developed for the GENIE nulling interferometer project at VLTI. We then propose a possible mission scenario, where the southern target stars of future exo-Earth characterisation missions can be surveyed for the presence of bright exozodiacal discs (>50 zodi) within one winter-over at Concordia.

Absil, O.; Coudé du Foresto, V.; Barillot, M.; Daudigeos, X.; Defrère, D.; den Hartog, R.; di Folco, E.; Surdej, J.

352

Lidar full-waveform data analysis for detection of faint returns through obscurants  

NASA Astrophysics Data System (ADS)

Innovative algorithm development for full-waveform lidar data processing extends this remote sensing technology's capabilities to even more complicated acquisition scenarios then previously determined, namely success of surveys over obscured areas. Waveform decomposition and the extraction of waveform metrics provide a straightforward approach to identifying vertical structure within each laser measurement. However, there are some limitations in this approach as faint returns within the waveform go undetected in the processing chain. These faint returns are the result of reduced energy levels due to obscurant scattering, attenuation and absorption. Lidar surveys over non-homogeneous wooded regions indicate that there are meaningful ground returns within dense tree coverage if extracted correctly from the data. One difficulty associated with detecting weaker returns is the presence of a hardware induced ring by the Avalanche Photo Diode (APD) detector in the returned waveform. By using a waveform stacking technique with adjacent waveforms in near geospatial proximity to the original, these faint returns can be augmented and detected during data processing without the inclusion of the false ring. In comparison to the traditional approach, the waveform stacking technique provides a 9% increase in faint signal extraction for the particular dataset. These faint signals are low level last returns that correspond to perceived ground reflections under canopy cover. The enhanced capability in the presence of foliage provides a decrease in operational effort associated with data density, dwell or targeting techniques and survey expense.

Magruder, Lori A.; Neuenschwander, Amy L.

2009-05-01

353

Exploring the spectral properties of faint hard X-ray sources with XMM-Newton  

E-print Network

We present a spectroscopic study of 41 hard X-ray sources detected serendipitously with high significance (> 5 sigma in the 2-10 keV band) in seven EPIC performance/verification phase observations. The large collecting area of EPIC allows us to explore the spectral properties of these faint hard X-ray sources with 2x 10^{-14} erg cm^{-2}s^{-1} even though the length of the exposures are modest (~ 20 ks). Optical identifications are available for 21 sources of our sample. Using a simple power law plus Galactic absorption model we find an average value of the photon index Gamma ~ 1.6-1.7, broadly consistent with recent measurements made at similar fluxes with ASCA and with Chandra stacked spectral analyses. We find that 31 out of 41 sources are well fitted by this simple model and only eight sources require absorption in excess of the Galactic value. Interestingly enough, one third of these absorbed sources are broad line objects, though with moderate column densities. Two sources in the sample are X-ray bright optically quiet galaxies and show flat X-ray spectra. Comparing our observational results with those expected from standard synthesis models of the cosmic X-ray background (CXB) we find a fraction of unabsorbed to absorbed sources larger than predicted by theoretical models at our completeness limit of F_{2-10} ~ 5 x 10^{-14} erg cm^{-2}s^{-1}. The results presented here illustrate well how wide-angle surveys performed with EPIC on board XMM-Newton allow population studies of interesting and unusual sources to be made as well as enabling constraints to be placed on some input parameters for synthesis models of the CXB.

E. Piconcelli; M. Cappi; L. Bassani; F. Fiore; G. DiCocco; J. B. Stephen

2002-08-08

354

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

355

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

356

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

357

Infrared Scanning  

NASA Technical Reports Server (NTRS)

United Scanning Technologies, Inc.'s Infrared thermography is a relatively new noncontact, nondestructive inspection and testing tool which makes temperatures visible to the human eye. Infrared scanning devices produce images that show, by color or black and white shading differences, heat losses through damaged or inadequately insulated walls or roofs. The MISS Aeroscan services are designed to take the guesswork out of industrial roof maintenance and provide companies big savings by identifying the location of moisture damage from roof leaks, effectively targeting maintenance attention.

1987-01-01

358

Infrared Thermometer  

NASA Technical Reports Server (NTRS)

Diatek Corporation, San Diego, CA and the Jet Propulsion Lab developed the Diatek Model 7000 aural thermometer which weighs only eight ounces, and measures temperature in less than two seconds using infrared astronomy technology to measure the amount of infrared energy emitted by the eardrum (the same way temperature of stars and planets is measured). This method avoids contact with mucous membranes, virtually eliminating the possibility of cross infection, and permits temperature measurement of newborn, critically ill, or incapacitated patients. Diatek Corporation was purchased by Welch Allyn Inc. The Diatek Model 7000 is now marketed as SureTemp.

1991-01-01

359

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

360

First results with the boloSource() algorithm: photometry of faint standard stars observed by Herschel/PACS  

NASA Astrophysics Data System (ADS)

The boloSource() algorithm is a tool to separate the signal of compact sources from that of the diffuse background in the timeline of far-infrared measurements performed by the PACS camera of the Herschel Space Observatory. An important characteristic and quality indicator of this method is that how well it can reproduce the flux of faint standard stars which have reliable flux estimates. For this propose we selected a few calibrator targets and constructed light curves by extracting point source flux for each repetition of the measurements independently using standard aperture photometry methods. These were compared with the light curves obtained using the boloSource() method on the same dataset. The results indicate that boloSource() provides a similar level of photometric accuracy and reproducibility as the usual flux extraction and photometry methods. This new technique will be developed further and also tested against other methods in more complex fields with the goal to make it usable for large-scale studies in the future.

Marton, G.; Vavrek, R.; Kiss, C.; Müller, T. G.

2014-07-01

361

Beyond the Hubble Deep Field Limiting Magnitude: Faint Galaxy Number Counts from Surface-Brightness Fluctuations  

E-print Network

The faint end of the differential galaxy number counts, n(m), in the Hubble Deep Field (HDF) North has been determined for the F450W, F606W, and F814W filters by means of surface-brightness fluctuation (SBF) measurements. This technique allows us to explore n(m) beyond the limiting magnitude of the HDF, providing new, stronger constraints on the faint end of n(m). This has allowed us to test the validity of previous number count studies and to produce a new determination of the faint end of n(m) for magnitudes fainter than 28.8 in the AB system and to extend this estimate down to 31. This value represents an extension of more than two magnitudes beyond the limits of previous photometric studies. The obtained n(m) slopes are \\gamma=0.27, 0.21, and 0.26 in B_{450}, V_{606}, and I_{814}, respectively.

A. Marin-Franch; A. Aparicio

2003-05-16

362

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

363

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

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

364

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

365

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.

C. P. Sherman Hsu

366

Infrared telescope  

NASA Technical Reports Server (NTRS)

The development of the Infrared Telescope for Spacelab 2 is discussed. The design, development, and testing required to interface a stationary superfluid helium dewar with a scanning cryostate capable of operating in the zero-g environment in the space shuttle bay is described.

Karr, G. R.; Hendricks, J. B.

1985-01-01

367

Infrared Thermometers  

ERIC Educational Resources Information Center

An infrared (IR) thermometer lab offers the opportunity to give science students a chance to measure surface temperatures, utilizing off-the-shelf technology. Potential areas of study include astronomy (exoplanets), electromagnetic spectrum, chemistry, evaporation rates, anatomy, crystal formation, and water or liquids. This article presents one…

Schaefers, John

2006-01-01

368

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

369

A Keck/DEIMOS spectroscopic survey of faint Galactic satellites: searching for the least massive dwarf galaxies  

NASA Astrophysics Data System (ADS)

We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Boötes, Ursa Major I, Ursa Major II and Willman 1 (Wil1). Using the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, we have obtained samples that contain from ~15 to ~85 probable members of these satellites for which we derive radial velocities precise to a few kms-1 down to i ~ 21-22. About half of these stars are observed with a high enough signal-to-noise ratio to estimate their metallicity to within +/-0.2 dex. The characteristics of all the observed stars are made available, along with those of the Canes Venatici I dwarf galaxy that have been analysed in a companion paper. From this data set, we show that Ursa Major II is the only object that does not show a clear radial velocity peak. However, the measured systemic radial velocity (vr = 115 +/- 5kms-1) is in good agreement with simulations in which this object is the progenitor of the recently discovered Orphan Stream. The three other satellites show velocity dispersions that make them highly dark matter dominated systems (under the usual assumptions of symmetry and virial equilibrium). In particular, we show that despite its small size and faintness, the Wil1 object is not a globular cluster given its metallicity scatter over -2.0 <~ [Fe/H] <~ -1.0 and is therefore almost certainly a dwarf galaxy or dwarf galaxy remnant. We measure a radial velocity dispersion of only 4.3+2.3-1.3kms-1 around a systemic velocity of -12.3 +/- 2.3kms-1 which implies a mass-to-light ratio of ~700 and a total mass of ~5 × 105Msolar for this satellite, making it the least massive satellite galaxy known to date. Such a low mass could mean that the 107Msolar limit that had until now never been crossed for Milky Way and Andromeda satellite galaxies may only be an observational limit and that fainter, less massive systems exist within the Local Group. However, more modelling and an extended search for potential extratidal stars are required to rule out the possibility that these systems have not been significantly heated by tidal interaction. The 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. E-mail: martin@mpia-hd.mpg.de ‡ Canadian Space Agency Fellow.

Martin, N. F.; Ibata, R. A.; Chapman, S. C.; Irwin, M.; Lewis, G. F.

2007-09-01

370

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

371

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

372

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

373

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

374

Emission lines in the Near-infrared Spectra of the IR Quintuplet Stars in the Galactic Center  

NASA Astrophysics Data System (ADS)

The natures of the five infrared stars for which the Galactic center’s “Quintuplet Cluster” were named have long been a mystery, although the pinwheel morphologies of two of them suggest that those two are Wolf-Rayet colliding wind binaries. Not only does each of the five IR stars suffer the same large interstellar extinction that obscures all objects in the Galactic center, but also each is embedded within its own warm and dusty cocoon. Until recently near-infrared spectra of them have revealed only dust continua steeply rising to long wavelengths. In the J and H bands the Quintuplet stars are very faint due to the high extinction, but the continuum emission from their warm cocoons is much less than at longer wavelengths and lines arising within their dust shells should be relatively more prominent. Here we report the detection of a number of emission lines characteristic of hot and massive stars in 1.0-1.8?m spectra of four of the IR Quintuplet stars. The lines that have been detected to date allow initial classifications of most of these stars.

Geballe, Thomas R.; Najarro, F.; de la Fuente, D.; Figer, D. F.

2014-01-01

375

Infrared floodlight  

DOEpatents

An infrared floodlight assembly designed particularly for security purposes and including a heat-conducting housing, a lens secured to the housing to provide a closure therefor, and a floodlight located within (and surrounded by) the housing. The floodlight combines the use of a tungsten halogen light source and dichroic hot and cold mirrors for directing substantially only infrared radiation toward the assembly's forward lens. Visible radiation is absorbed by the housing's interior wall(s) and, optionally, by a filter located between the floodlight and lens. An optional means may be used within the floodlight to reflect all forward radiation back toward the paraboloidal hot mirror or, alternatively, to reflect only visible radiation in this direction. The dichroic hot and cold mirrors preferably each comprise a glass substrate having multiple layers of titanium dioxide and silicon dioxide thereon.

Levin, Robert E. (S. Hamilton, MA); English, George J. (Reading, MA)

1986-08-05

376

Optical Structure and Colors of Faint Compact Narrow Emission-Line Galaxies  

Microsoft Academic Search

We present the results of Hubble Space Telescope Wide Field Planetary Camera imaging in V606 and I814 of five compact narrow emission line galaxies (CNELGs) and four slightly more extended faint blue galaxies (FBGs) with 20.3<=B<=22.4 and redshifts z~0.22 -0.66. Half-light radii are measured to span from 0.\\

Rafael Guzman; Anna Jangren; David C. Koo; Matthew A. Bershady; Luc Simard

1998-01-01

377

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

E-print Network

of ads that splash "blood money" on Mitt Romney's record or whip out Newt Gingrich's ethics "baggageCampaign 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.

378

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.

379

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

380

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

381

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

382

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

383

Strategies for prompt searches for GRB afterglows: the discovery of the GRB 001011 optical/near-infrared counterpart using colour-colour selection  

E-print Network

We report the discovery of the optical and near-infrared counterparts 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. Here 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 ~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+/-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 error boxes determined by future missions.

J. Gorosabel; J. U. Fynbo; J. Hjorth; C. Wolf; M. I. Andersen; H. Pedersen; L. Christensen; B. L. Jensen; P. Moller; J. Afonso; M. A. Treyer; G. Mallen-Ornelas; A. J. Castro-Tirado; A. Fruchter; J. Greiner; E. Pian; P. M. Vreeswijk; F. Frontera; L. Kaper; S. Klose; C. Kouveliotou; N. Masetti; E. Palazzi; E. Rol; I. Salamanca; N. Tanvir; R. A. M. J. Wijers; E. van den Heuvel

2001-11-14

384

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

385

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

386

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.

387

Detecting faint echoes in stellar-flare light curves  

NASA Technical Reports Server (NTRS)

Observational considerations are discussed for detecting echoes from flare-star photospheres and from stellar or planetary companions. Synthetic spectra are used to determine optimal conditions for the recovery of echoes in flare light curves. The most detectable echoes are expected to appear in broadband observations of the UV continuum. Short-lived flares are ideal for resolving echoes from the flare-star photosphere and may provide constraints for stellar-flare models. Strong outbursts may be used to detect stellar or planetary companions of a flare star. However, the possible planetary configurations that may be probed by this method are limited to Jupiter-size objects in tight orbits about the parent star.

Bromley, Benjamin C.

1992-01-01

388

Distributed Objects and object persistence Distributed objects  

E-print Network

getAge() throws Throwable; public String getName() throws Throwable; } · Client uses the object just as if it were local public class PersonClient { public static void main(String[] argsStream.readInt(); } public String getName()throws Throwable{ ... } } 6 From the server side

Lu, Jianguo

389

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

390

Detection of latent fingerprints by near-infrared spectral imaging  

NASA Astrophysics Data System (ADS)

Spectral imaging technology research is becoming more extensive in the field of examination of material evidence. Near-Infrared spectral imaging technology is an important part of the full spectrum of imaging technology. This paper finished the experiment contents of the Near-Infrared spectrum imaging method and image acquisition system Near-Infrared spectral imaging technology. The experiment of Near-Infrared spectral imaging method obtains the image set of the Near-Infrared spectrum, and formats a pseudo-color images to show the potential traces successfully by processing the set of spectral images; Near-Infrared spectral imaging technology explores the technology method of obtaining the image set of Near-Infrared spectrometer and image acquisition system, and extensive access to the Near-Infrared spectrum information of latent blood, stamp and smear fingerprints on common objects, and study the characteristics of the Near-Infrared spectrum. Near-Infrared spectroscopic imaging experiments explores a wide variety of Near-Infrared reflectance spectra of the object material curve and its Near-Infrared spectrum of imaging modalities, can not only gives a reference for choosing Near-Infrared wavelength to show the object surface potential traces of substances, but also gives important data for the Near-Infrared spectrum of imaging technology development.

Huang, Wei; Dai, Yong

2014-05-01

391

CCD time-resolved photometry of faint cataclysmic variables. II  

SciTech Connect

Time-resolved optical broad-band light curves obtained from differential photometry on sequential CCD frames of the known or suspected cataclysmic variable FO And, EH Aqr, WX Cet, XX Cet, AL Com, V503 Cyg, AH Eri, CP Eri, IR Gem, RW UMi, PG0134+070, and US 3215 are presented. The analysis of the light curves with coverage of greater than 2 hrs shows repeatable periodicity in five objects. PG0134+070 exhibits eclipses of 1.3-1.8 mag depth with a period of 313 min. V503 Cyg has a 0.7-1.0 mag peak-to-peak modulation with a period of 109 min. IR Gem shows a large modulation at the orbital period of 99 min, and comparison with previous data indicates that this modulation may have an amplitude dependent on outburst phase. AH Eri reveals a 0.1-0.3 mag modulation, at a period of 42 min. Better time-resolved data on AL Com confirm the 0.4-mag variation reported by Howell and Szkody (1988) at a period of 42 min. These latter two short periods likely indicate magnetic systems. There is also some evidence of periodicity in RW UMi and WX Cet which must be confirmed with further data. 25 refs.

Szkody, P.; Howell, S.B.; Mateo, M.; Kreidl, T.J. (Washington Univ., Seattle (USA) Planetary Science Institute, Tucson, AZ (USA) Mount Wilson and Las Campanas Observatories, Pasadena, CA (USA) Lowell Observatory, Flagstaff, AZ (USA))

1989-10-01

392

Parallel object-oriented data mining system  

DOEpatents

A data mining system uncovers patterns, associations, anomalies and other statistically significant structures in data. Data files are read and displayed. Objects in the data files are identified. Relevant features for the objects are extracted. Patterns among the objects are recognized based upon the features. Data from the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) sky survey was used to search for bent doubles. This test was conducted on data from the Very Large Array in New Mexico which seeks to locate a special type of quasar (radio-emitting stellar object) called bent doubles. The FIRST survey has generated more than 32,000 images of the sky to date. Each image is 7.1 megabytes, yielding more than 100 gigabytes of image data in the entire data set.

Kamath, Chandrika; Cantu-Paz, Erick

2004-01-06

393

Infrared upconversion hyperspectral imaging.  

PubMed

In this Letter, hyperspectral imaging in the mid-IR spectral region is demonstrated based on nonlinear frequency upconversion and subsequent imaging using a standard Si-based CCD camera. A series of upconverted images are acquired with different phase match conditions for the nonlinear frequency conversion process. From this, a sequence of monochromatic images in the 3.2-3.4 ?m range is generated. The imaged object consists of a standard United States Air Force resolution target combined with a polystyrene film, resulting in the presence of both spatial and spectral information in the infrared image. PMID:25768151

Kehlet, Louis Martinus; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin; Pedersen, Christian

2015-03-15

394

Cognitive Objects.  

ERIC Educational Resources Information Center

Reflecting on obsessional play objects of infants, Hodgkin suggests that a proper understanding of these "transitional" or "cognitive" objects could lead to an educational model of a "learner" involving a number of human competencies, all developing synergistically. Contends that such a model may be truer to life than the more unified and…

Hodgkin, Robin A.

1988-01-01

395

Objective lens  

NASA Technical Reports Server (NTRS)

An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

Olczak, Eugene G. (Inventor)

2011-01-01

396

Object identity  

Microsoft Academic Search

Identity is that property of an object which distinguishes each object from all others. Identity has been investigated almost independently in general-purpose programming languages and database languages. Its importance is growing as these two environments evolve and merge.We describe a continuum between weak and strong support of identity, and argue for the incorporation of the strong notion of identity at

Setrag N. Khoshafian; George P. Copeland

1986-01-01

397

A faint galaxy redshift survey behind massive clusters  

SciTech Connect

This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of {approximately}20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

Frye, Brenda

1999-12-01

398

Rapid infrared heating of a surface  

DOEpatents

High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

Sikka, Vinod K.; Blue, Craig A.; Ohriner, Evan Keith

2003-12-23

399

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.

400

Rapid infrared heating of a surface  

DOEpatents

High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

Sikka, Vinod K. (Oak Ridge, TN); Blue, Craig A. (Concord, TN); Ohriner, Evan Keith (Knoxville, TN)

2001-01-01

401

Rapid infrared heating of a surface  

DOEpatents

High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

Sikka, Vinod K. (Oak Ridge, TN); Blue, Craig A. (Concord, TN); Ohriner, Evan Keith (Knoxville, TN)

2002-01-01

402

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

403

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 polycyc