Sample records for faint object infrared

  1. Faint Infrared-Excess Field Galaxies FROGs

    E-print Network

    Moustakas, L A; Zepf, S E; Bunker, A J

    1997-01-01

    Deep near-infrared and optical imaging surveys in the field reveal a curious population of galaxies that are infrared-bright (I-K>4), yet with relatively blue optical colors (V-I20, is high enough that if placed at z>1 as our models suggest, their space densities are about one-tenth of phi-*. The colors of these ``faint red outlier galaxies'' (fROGs) may derive from exceedingly old underlying stellar populations, a dust-embedded starburst or AGN, or a combination thereof. Determining the nature of these fROGs, and their relation with the I-K>6 ``extremely red objects,'' has implications for our understanding of the processes that give rise to infrared-excess galaxies in general. We report on an ongoing study of several targets with HST & Keck imaging and Keck/LRIS multislit spectroscopy.

  2. Faint Infrared-Excess Field Galaxies: FROGs

    E-print Network

    L. A. Moustakas; M. Davis; S. E. Zepf; A. J. Bunker

    1997-12-10

    Deep near-infrared and optical imaging surveys in the field reveal a curious population of galaxies that are infrared-bright (I-K>4), yet with relatively blue optical colors (V-I20, is high enough that if placed at z>1 as our models suggest, their space densities are about one-tenth of phi-*. The colors of these ``faint red outlier galaxies'' (fROGs) may derive from exceedingly old underlying stellar populations, a dust-embedded starburst or AGN, or a combination thereof. Determining the nature of these fROGs, and their relation with the I-K>6 ``extremely red objects,'' has implications for our understanding of the processes that give rise to infrared-excess galaxies in general. We report on an ongoing study of several targets with HST & Keck imaging and Keck/LRIS multislit spectroscopy.

  3. Infrared-Faint Radio Sources are at high redshifts

    E-print Network

    Herzog, Andreas; Norris, Ray P; Sharp, Rob; Spitler, Lee R

    2013-01-01

    Context. Infrared-Faint Radio Sources (IFRS) are characterised by relatively high radio flux densities and associated faint or even absent infrared and optical counterparts. The resulting extremely high radio-to-infrared flux density ratios up to several thousands were previously known only for High-redshift Radio Galaxies (HzRGs), suggesting a link between these classes of object. However, the optical and infrared faintness of IFRS makes their study diffcult. So far, no redshift is known for an original IFRS which would help to put IFRS in the context of other classes of object, especially of HzRGs. Aims. This work tests the hypothesis that IFRS follow the relation between 3.6 um flux density and redshift found for HzRGs. Furthermore, redshifts will enable us to reveal the intrinsic radio and infrared properties of IFRS and we will test the current suggestions that IFRS are high-redshift radio-loud active galactic nuclei. Methods. A sample of IFRS was spectroscopically observed using the Focal Reducer and lo...

  4. Are the infrared-faint radio sources pulsars?

    NASA Astrophysics Data System (ADS)

    Cameron, A. D.; Keith, M.; Hobbs, G.; Norris, R. P.; Mao, M. Y.; Middelberg, E.

    2011-07-01

    Infrared-faint radio sources (IFRS) are objects which are strong at radio wavelengths but undetected in sensitive Spitzer observations at infrared wavelengths. Their nature is uncertain and most have not yet been associated with any known astrophysical object. One possibility is that they are radio pulsars. To test this hypothesis we undertook observations of 16 of these sources with the Parkes Radio Telescope. Our results limit the radio emission to a pulsed flux density of less than 0.21 mJy (assuming a 50 per cent duty cycle). This is well below the flux density of the IFRS. We therefore conclude that these IFRS are not radio pulsars.

  5. Are the infrared-faint radio sources pulsars?

    E-print Network

    Keith, A D Cameron M J; Norris, R P; Mao, M Y; Middelberg, E

    2011-01-01

    Infrared-Faint Radio Sources (IFRS) are objects which are strong at radio wavelengths but undetected in sensitive Spitzer observations at infrared wavelengths. Their nature is uncertain and most have not yet been associated with any known astrophysical object. One possibility is that they are radio pulsars. To test this hypothesis we undertook observations of 16 of these sources with the Parkes Radio Telescope. Our results limit the radio emission to a pulsed flux density of less than 0.21 mJy (assuming a 50% duty cycle). This is well below the flux density of the IFRS. We therefore conclude that these IFRS are not radio pulsars.

  6. Hubble Space Telescope, Faint Object Camera

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This drawing illustrates Hubble Space Telescope's (HST's), Faint Object Camera (FOC). The FOC reflects light down one of two optical pathways. The light enters a detector after passing through filters or through devices that can block out light from bright objects. Light from bright objects is blocked out to enable the FOC to see background images. The detector intensifies the image, then records it much like a television camera. For faint objects, images can be built up over long exposure times. The total image is translated into digital data, transmitted to Earth, and then reconstructed. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  7. Morphology and astrometry of Infrared-Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Middelberg, Enno; Norris, Ray; Randall, Kate; Mao, Minnie; Hales, Christopher

    2008-10-01

    Infrared-Faint Radio Sources, or IFRS, are an unexpected class of object discovered in the Australia Telescope Large Area Survey, ATLAS. They are compact 1.4GHz radio sources with no visible counterparts in co-located (relatively shallow) Spitzer infrared and optical images. We have detected two of these objects with VLBI, indicating the presence of an AGN. These observations and our ATLAS data indicate that IFRS are extended on scales of arcseconds, and we wish to image their morphologies to obtain clues about their nature. These observations will also help us to select optical counterparts from very deep, and hence crowded, optical images which we have proposed. With these data in hand, we will be able to compare IFRS to known object types and to apply for spectroscopy to obtain their redshifts.

  8. Hubble Space Telescope, Faint Object Spectrograph

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This drawing illustrates the Hubble Space Telescope's (HST's), Faint Object Spectrograph (FOS). The HST's two spectrographs, the Goddard High-Resolution Spectrograph and the FOS, can detect a broader range of wavelengths than is possible from the Earth because there is no atmosphere to absorb certain wavelengths. Scientists can determine the chemical composition, temperature, pressure, and turbulence of the stellar atmosphere producing the light, all from spectral data. The FOC can detect detail in very faint objects, such as those at great distances, and light ranging from ultraviolet to red spectral bands. Both spectrographs operate in essentially the same way. The incoming light passes through a small entrance aperture, then passes through filters and diffraction gratings, that work like prisms. The filter or grating used determines what range of wavelength will be examined and in what detail. Then the spectrograph detectors record the strength of each wavelength band and sends it back to Earth. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  9. VLBI observations of Infrared-Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Middelberg, Enno; Phillips, Chris; Norris, Ray; Tingay, Steven

    2006-10-01

    We propose to observe a small sample of radio sources from the ATLAS project (ATLAS = Australia Telescope Large Area Survey) with the LBA, to determine their compactness and map their structures. The sample consists of three radio sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubbed Infrared-Faint Radio Sources, or IFRS, is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations: we will map their structure to test whether they resemble core-jet or double-lobed morphologies, and we will measure the flux densities on long baselines, to determine their compactness. Previous snapshot-style LBA observations of two other IFRS yielded no detections, hence we propose to use disk-based recording with 512 Mbps where possible, for highest sensitivity. With the observations proposed here, we will increase the number of VLBI-observed IFRS from two to five, soon allowing us to draw general conclusions about this intriguing new class of objects.

  10. X-ray Counterparts of Infrared Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Schartel, Norbert

    2011-10-01

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

  11. The radio properties of infrared-faint radio sources

    E-print Network

    Middelberg, Enno; Hales, Christopher A; Seymour, Nick; Johnston-Hollitt, Melanie; Huynh, Minh T; Lenc, Emil; Mao, Minnie Y

    2010-01-01

    Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4GHz, but that are invisible at 3.6um when using sensitive Spitzer observations with uJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. We imaged a sample of 17 IFRS at 4.8GHz and 8.6GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spec...

  12. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

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

  13. The radio properties of infrared-faint radio sources

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Norris, R. P.; Hales, C. A.; Seymour, N.; Johnston-Hollitt, M.; Huynh, M. T.; Lenc, E.; Mao, M. Y.

    2011-02-01

    Context. Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4 GHz, but that are invisible at 3.6 ?m when using sensitive Spitzer observations with ?Jy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. Aims: High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. Methods: We imaged a sample of 17 IFRS at 4.8 GHz and 8.6 GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. Results: We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spectral indices larger than -0.7. We also find that, given the IR non-detections, the ratio of 1.4 GHz flux density to 3.6 ?m flux density is very high, and this puts them into the same regime as high-redshift radio galaxies. Conclusions: The evidence that IFRS are predominantly high-redshift sources driven by active galactic nuclei (AGN) is strong, even though not all IFRS may be caused by the same phenomenon. Compared to the rare and painstakingly collected high-redshift radio galaxies, IFRS appear to be much more abundant, but less luminous, AGN-driven galaxies at similar cosmological distances.

  14. Observations of faint objects with laser beacon adaptive optics

    Microsoft Academic Search

    Robert Q. Fugate

    1994-01-01

    This paper reports progress in the use of laser beacons for compensating the images of faint objects using adaptive optics. The system describe is located at the USAF Phillips Laboratory's Starfire Optical Range near Albuquerque, New Mexico on a 1.5 m telescope. The adaptive optics system uses a 241 actuator continuous facesheet deformable mirror. A copper vapor laser beacon focused

  15. Infrared Faint Radio Sources in the Extended Chandra Deep Field South

    NASA Astrophysics Data System (ADS)

    Huynh, Minh T.

    2009-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE). The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift AGN (z > 2).

  16. Fainting

    MedlinePLUS

    ... movement (especially if you are straining) Have been standing in one place for too long Urinate Fainting ... such as from bleeding or being severely dehydrated ) Standing up very suddenly from a lying position Less ...

  17. Fainting

    MedlinePLUS

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

  18. The faint object camera (phase a). Volume 2: Detector design

    Microsoft Academic Search

    A. Boksenberg; P. J. Bowen; C. I. Coleman; R. Nettleship; D. Weighton

    1976-01-01

    Detector options were considered for the faint object camera of the NASA 2.4 m space telescope. Performance figures were recalculated for the most promising systems identified during previous studies. The systems are the following: I4-P four-stage magnetic focus intensifier, lens coupled to PbO vidicon; I2-EBS two stage magnetic focus intensifier, lens coupled to 25 mm or (40 mm EBS tube;

  19. Do the enigmatic ``Infrared-Faint Radio Sources'' include pulsars?

    NASA Astrophysics Data System (ADS)

    Hobbs, George; Middelberg, Enno; Norris, Ray; Keith, Michael; Mao, Minnie; Champion, David

    2009-04-01

    The Australia Telescope Large Area Survey (ATLAS) team have surveyed seven square degrees of sky at 1.4GHz. During processing some unexpected infrared-faint radio sources (IFRS sources) were discovered. The nature of these sources is not understood, but it is possible that some of these sources may be pulsars within our own galaxy. We propose to observe the IFRS sources with steep spectral indices using standard search techniques to determine whether or not they are pulsars. A pulsar detection would 1) remove a subset of the IFRS sources from the ATLAS sample so they would not need to be observed with large optical/IR telescopes to find their hosts and 2) be intrinsically interesting as the pulsar would be a millisecond pulsar and/or have an extreme spatial velocity.

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

    SciTech Connect

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

    2010-02-10

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

  1. Stellar Ultraviolet Rocket Research Program. [faint object spectrograph

    NASA Technical Reports Server (NTRS)

    1984-01-01

    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.

  2. The first VLBI image of an infrared-faint radio source

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Norris, R. P.; Tingay, S.; Mao, M. Y.; Phillips, C. J.; Hotan, A. W.

    2008-11-01

    Context: We investigate the joint evolution of active galactic nuclei and star formation in the Universe. Aims: In the 1.4 GHz survey with the Australia Telescope Compact Array of the Chandra Deep Field South and the European Large Area ISO Survey - S1 we have identified a class of objects which are strong in the radio but have no detectable infrared and optical counterparts. This class has been called Infrared-Faint Radio Sources, or IFRS. 53 sources out of 2002 have been classified as IFRS. It is not known what these objects are. Methods: To address the many possible explanations as to what the nature of these objects is we have observed four sources with the Australian Long Baseline Array. Results: We have detected and imaged one of the four sources observed. Assuming that the source is at a high redshift, we find its properties in agreement with properties of Compact Steep Spectrum sources. However, due to the lack of optical and infrared data the constraints are not particularly strong.

  3. A search for AGN activity in Infrared-Faint Radio Sources (IFRS)

    NASA Astrophysics Data System (ADS)

    Lenc, Emil; Middelberg, Enno; Norris, Ray; Mao, Minnie

    2010-04-01

    We propose to observe a large sample of radio sources from the ATLAS (Australia Telescope Large Area Survey) source catalogue with the LBA, to determine their compactness. The sample consists of 36 sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubber Infrared-Faint Radio Sources (IFRS), is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations. We will measure the flux densities on long baselines to determine their compactness. Only five IFRS have been previously targeted with VLBI observations (resulting in two detections). We propose using single baseline (Parkes-ATCA) eVLBI observations with the LBA at 1 Gbps to maximise sensitivity. With the observations proposed here we will increase the number of VLBI-observed IFRS from 5 to 36, allowing us to draw statistical conclusions about this intriguing new class of objects.

  4. A search for AGN activity in Infrared-Faint Radio Sources (IFRS)

    NASA Astrophysics Data System (ADS)

    Lenc, Emil; Middelberg, Enno; Norris, Ray; Mao, Minnie

    2009-04-01

    We propose to observe a large sample of radio sources from the ATLAS (Australia Telescope Large Area Survey) source catalogue with the LBA, to determine their compactness. The sample consists of 36 sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubber Infrared-Faint Radio Sources (IFRS), is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations. We will measure the flux densities on long baselines to determine their compactness. Only five IFRS have been previously targeted with VLBI observations (resulting in two detections). We propose using single baseline (Parkes-ATCA) eVLBI observations with the LBA at 1 Gbps to maximise sensitivity. With the observations proposed here we will increase the number of VLBI-observed IFRS from 5 to 36, allowing us to draw statistical conclusions about this intriguing new class of objects.

  5. Strategies for Imaging Faint Extended Sources in the Near-Infrared

    Microsoft Academic Search

    Ovidiu Vaduvescu; Marshall L. McCall

    2004-01-01

    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 that occupy a significant fraction of the field of view of a detector or that are located in areas crowded with foreground or background sources.

  6. Mon. Not. R. Astron. Soc. 000, 000000 (0000) Printed 25 February 2011 (MN LATEX style file v2.2) Are the infrared-faint radio sources pulsars?

    E-print Network

    Norris, Ray

    , Universit¨atsstr. 150, 44801 Bochum, Germany ABSTRACT Infrared-Faint Radio Sources (IFRS) are objects which of less than 0.21 mJy (assum- ing a 50% duty cycle). This is well below the flux density of the IFRS. We therefore conclude that these IFRS are not radio pulsars. Key words: surveys, pulsars: general 1

  7. Counts, Sizes and Colours of Faint Infrared-Selected Galaxies

    NASA Astrophysics Data System (ADS)

    Saracco, Paolo; D'Odorico, Sandro; Moorwood, Alan; Cuby, Jean G.

    2001-03-01

    Deep J- and K_s-band images covering a 5 × 5 arcmin area centred on the NTT Deep Field have been obtained during the Science Verification of SOFI at the NTT. These images were made available via the Web in early June, 1998. The preliminary results we have obtained by the analysis of these data are the following: (i) the counts continue to rise with no evidence of a turnover or of a flattening down to the limits of the survey (K_s = 22.5 and J = 24 mag); (ii) we find a slope d log(N)/dm ~ 0.37, in agreement with most of the faintest surveys but much steeper than the Hawaii survey; (iii) fainter than K_s ~ 19 and J ~ 20 mag, the median J-K colour of galaxies shows a break in its reddening trend turning toward bluer colours; (iv) faint bluer galaxies also display a larger compactness index, and a smaller apparent size.

  8. Four Faint T Dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Southern Stripe

    E-print Network

    Kuenley Chiu; Michael C. Liu; Linhua Jiang; Katelyn N. Allers; Daniel P. Stark; Andrew Bunker; Xiaohui Fan; Karl Glazebrook; Trent J. Dupuy

    2007-12-08

    We present the optical and near-infrared photometry and spectroscopy of four faint T dwarfs newly discovered from the UKIDSS first data release. The sample, drawn from an imaged area of ~136 square degrees to a depth of Y=19.9 (5-sigma, Vega), is located in the SDSS Southern Equatorial Stripe, a region of significant future deep imaging potential. We detail the selection and followup of these objects, three of which are spectroscopically confirmed brown dwarfs ranging from type T2.5 to T7.5, and one is photometrically identified as early T. Their magnitudes range from Y=19.01 to 19.88 with derived distances from 34 to 98 pc, making these among the coldest and faintest brown dwarfs known. The sample brings the total number of T dwarfs found or confirmed by UKIDSS data in this region to nine, and we discuss the projected numbers of dwarfs in the future survey data. We estimate that ~240 early- and late-T dwarfs are discoverable in the UKIDSS LAS data, falling significantly short of published model projections and suggesting that IMFs and/or birthrates may be at the low end of possible models. Thus, deeper optical data has good potential to exploit the UKIDSS survey depth more fully, but may still find the potential Y dwarf sample to be extremely rare.

  9. Four Faint T Dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Southern Stripe

    E-print Network

    Chiu, Kuenley; Jiang, Linhua; Allers, Katelyn N; Stark, Daniel P; Bunker, Andrew; Fan, Xiaohui; Glazebrook, Karl; Dupuy, Trent J

    2007-01-01

    We present the optical and near-infrared photometry and spectroscopy of four faint T dwarfs newly discovered from the UKIDSS first data release. The sample, drawn from an imaged area of ~136 square degrees to a depth of Y=19.9 (5-sigma, Vega), is located in the SDSS Southern Equatorial Stripe, a region of significant future deep imaging potential. We detail the selection and followup of these objects, three of which are spectroscopically confirmed brown dwarfs ranging from type T2.5 to T7.5, and one is photometrically identified as early T. Their magnitudes range from Y=19.01 to 19.88 with derived distances from 34 to 98 pc, making these among the coldest and faintest brown dwarfs known. The sample brings the total number of T dwarfs found or confirmed by UKIDSS data in this region to nine, and we discuss the projected numbers of dwarfs in the future survey data. We estimate that ~240 early- and late-T dwarfs are discoverable in the UKIDSS LAS data, falling significantly short of published model projections a...

  10. Pencil-Beam Surveys for Faint Trans-Neptunian Objects

    E-print Network

    Brett Gladman; JJ Kavelaars; Philip D. Nicholson; Thomas J. Loredo; Joseph A. Burns

    1998-06-25

    We have conducted pencil-beam searches for outer solar system objects to a limiting magnitude of R ~ 26. Five new trans-neptunian objects were detected in these searches. Our combined data set provides an estimate of ~90 trans-neptunian objects per square degree brighter than ~ 25.9. This estimate is a factor of 3 above the expected number of objects based on an extrapolation of previous surveys with brighter limits, and appears consistent with the hypothesis of a single power-law luminosity function for the entire trans-neptunian region. Maximum likelihood fits to all self-consistent published surveys with published efficiency functions predicts a cumulative sky density Sigma(objects per square degree brighter than a given magnitude R.

  11. Infrared-faint radio sources remain undetected at far-infrared wavelengths. Deep photometric observations using the Herschel Space Observatory

    E-print Network

    Herzog, Andreas; Middelberg, Enno; Spitler, Lee R; Leipski, Christian; Parker, Quentin A

    2015-01-01

    Showing 1.4 GHz flux densities in the range of a few to a few tens of mJy, infrared-faint radio sources (IFRS) are a type of galaxy characterised by faint or absent near-infrared counterparts and consequently extreme radio-to-infrared flux density ratios up to several thousand. Recent studies showed that IFRS are radio-loud active galactic nuclei (AGNs) at redshifts >=2. This work explores the far-infrared emission of IFRS, providing crucial information on the star forming and AGN activity of IFRS and on the potential link between IFRS and high-redshift radio galaxies (HzRGs). A sample of six IFRS was observed with the Herschel Space Observatory between 100 um and 500 um. Using these results, we constrained the nature of IFRS by modelling their broad-band spectral energy distribution (SED). Furthermore, we set an upper limit on their infrared SED and decomposed their emission into contributions from an AGN and from star forming activity. All six observed IFRS were undetected in all five Herschel far-infrared ...

  12. Discovery of Faint Kuiper Belt Objects with the MOSIAC Cameras

    NASA Astrophysics Data System (ADS)

    Millis, Robert L.; Buie, Marc W.; Wagner, R. Mark; Elliot, James L.

    2000-02-01

    Astronomers today are poised at the edge of a new frontier. With the discovery of the Kuiper Belt has come the realization that the Solar System beyond Neptune is not effectively empty, but rather contains tens of thousands of intriguing orbiting bodies. Only about 200 or these Kuiper Belt Objects (KBOs) have been discovered at this writing. Yet they promise fundamental insights into the physical and dynamical processes which sculpted the outer regions of the solar system. To understand the Kuiper Belt, we must probe its radial extent, discover the distribution of objects with ecliptic longitude and latitude, learn the size distribution of the KBOs, and establish the orbits of these bodies - both to reveal the relevant dynamical processes and to facilitate physical studies with large-aperture telescopes on the ground and in space. These scientific objectives can be accomplished only through a carefully planned, wide ranging reconnaissance. Here we propose to continue our highly successful program at KPNO and to extend it into the Southern Hemisphere using the newly commissioned Mosaic Camera on the Blanco Telescope.

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

    Microsoft Academic Search

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

    1998-01-01

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

  14. Faint Blue Objects in the Hubble Deep Field South Revealed: White Dwarfs, Subdwarfs, and Quasars

    E-print Network

    Mukremin Kilic; R. A. Mendez; Ted von Hippel; D. E. Winget

    2005-07-22

    We explore the nature of the faint blue objects in the Hubble Deep Field South. We have derived proper motions for the point sources in the Hubble Deep Field South using a 3 year baseline. Combining our proper motion measurements with spectral energy distribution fitting enabled us to identify 4 quasars and 42 stars, including 3 white dwarf candidates. Two of these white dwarf candidates, HDFS 1444 and 895, are found to display significant proper motion, 21.1 $\\pm$ 7.9 mas/yr and 34.9 $\\pm$ 8.0 mas/yr, and are consistent with being thick disk or halo white dwarfs located at ~2 kpc. The other faint blue objects analyzed by Mendez & Minniti do not show any significant proper motion and are inconsistent with being halo white dwarfs; they do not contribute to the Galactic dark matter. The observed population of stars and white dwarfs is consistent with standard Galactic models.

  15. Strategies for Imaging Faint Extended Sources in the Near-Infrared

    NASA Astrophysics Data System (ADS)

    Vaduvescu, Ovidiu; McCall, Marshall L.

    2004-07-01

    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 that occupy a significant fraction of the field of view of a detector or that are located in areas crowded with foreground or background sources. Findings are based primarily on data acquired over three photometric nights with the 3.6m×3.6m CFHT-IR array on the Canada-France-Hawaii Telescope (CFHT) 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. During the run, the mean brightness of the background (more than 70% of which was from the sky) varied significantly on a very short timescale: by 0.7% per minute in J and 0.5% per minute in K', on average. Changes in the optical depth of the sky were partly responsible, because stars faded as the background level increased. A changing pattern in the background was evident from differences of consecutive pairs of frames (0.3% per minute in J and 0.2% per minute in K'), but this originated primarily in the instrumentation. Any pattern over 3.6m associated with the atmosphere changed at a rate less than about 0.06% per minute in K' relative to the signal from the sky alone. To measure the background to a precision of 1% per frame, exposures of extended targets should be alternated with identical exposures of the background. In J and K', target and sky exposures ought to be separated by no more than 90 and 130 s, respectively. To observe a target larger than about 40% of the field of view, background samples ought to be taken with the target shifted completely out of the field. For smaller targets, gains in efficiency can be made by shifting the target to a different place on the array. The signal-to-noise ratio of the reduced image of a target is maximized by evaluating the background for each individual image using only the samples taken immediately before and after. Provided background images are dithered, it is possible to recognize and remove celestial contaminants through differencing.

  16. A microshutter-based field selector for JWST's multi-object near infrared spectrograph

    Microsoft Academic Search

    Robert F. Silverberg; Richard Arendt; David E. Franz; Gunther Kletetschka; Alexander Kutyrev; Mary J. Li; S. Harvey Moseley; David A. Rapchun; Stephen Snodgrass; David W. Sohl; Leroy Sparr

    2007-01-01

    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

  17. Ground-based Mid-Infrared Spectroscopy of Faint Standard Stars in the North Ecliptic Polar Region for the ASTRO-F Infrared Camera

    NASA Astrophysics Data System (ADS)

    Ishihara, Daisuke; Onaka, Takashi; Kataza, Hirokazu; Miyata, Takashi; Okamoto, Yoshiko K.; Yamashita, Takuya; Sako, Sigeyuki; Honda, Mitsuhiko; Okada, Yoko; Fujiyoshi, Takuya; Cohen, Martin

    2006-02-01

    Faint standard stars in the mid-infrared region (less than a few hundred millijanskys at 9 ?m) are required for the on-orbit calibration of the Infrared Camera (IRC) on board ASTRO-F because of its high sensitivity, as well as the small dynamic range. Mid-infrared low-resolution (?/??~250) spectra of six faint K and M giant stars (70-180 mJy at 9 ?m, K1.5-M0 III), which are located in the north ecliptic polar region and are thus suitable for calibrators for the IRC, are obtained by using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru telescope to test the faint-infrared standard-star network recently constructed for space-borne instruments. The spectra are directly calibrated relative to Vega (A0 V). The present results indicate that the spectra of the faint standard K-M0 giant stars show good agreement with those predicted in the standard network within 10% accuracy on average. The overall spectral shapes are also in agreement with the predictions. In particular, the observed SiO absorption feature in the 8 ?m region matches well with the prediction for an M0 III star. The present observations directly connect a primary standard calibrator (Vega) to faint K giant calibrators of the network in the 10 ?m region and validate several faint (~0.1 Jy) members of the standard-star network for the first time. Absolute calibrations are provided for five of the medium-band filters of the COMICS instrument in the 10 ?m window. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  18. Faint quasi-stellar-object candidates in selected areas 28 and 68 identified from multicolor photometry

    SciTech Connect

    Shields, J.C.; Koo, D.C.; Kron, R.C. (Space Telescope Science Institute, Baltimore, MD (USA); California Univ., Berkeley (USA); Lick Observatory, Santa Cruz, CA (USA); Yerkes Observatory, Williams Bay, WI (USA))

    1989-04-01

    Forty-five QSO candidates over a total area of 0.53 square degree in two fields at high Galactic latitudes have been identified. These candidates reached B of about 21.5 for field Lynx.3 in SA 28 and B of about 22 for field SA68.2, and were selected from a subset of objects in catalogs generated from multicolor photometry (UBV) of deep Kitt Peak 4-m plates with limits of B of about 24. This subset consists of all objects which appeared stellar-like in size but which did not have the UBV colors of common Galactic stars. Besides several probable high-redshift QSOs, this study yields faint QSO counts consistent with those from other surveys, and thus provides further support to models that include mainly the luminosity evolution of QSOs. 29 refs.

  19. Infrared Properties of Edge-on Young Stellar Object Disks

    NASA Astrophysics Data System (ADS)

    Stapelfeldt, Karl; McCabe, Caer-Eve; Menard, Francois; Padgett, Deborah; Pontoppidan, Klaus

    2006-05-01

    Young, edge-on circumstellar disks are uniquely valuable laboratories for the study of planet formation. In these objects, the central star is occulted from direct view, significant stellar PSF artifacts are absent, and the disk is clearly seen as a central dust lane flanked by faint bands of reflected light. The detailed morphology of these nebulae and its variation with wavelength provides crucial information not availble for other young star disks. The disk inclination, density structure, and dust grain properties can be quantitatively constrained by fitting Monte Carlo scattered light models to high resolution images. While edge-on disks are among the best-understood disks in 2-D images, their spectral energy distributions are still poorly characterized and modeled. Very high extinctions and small projected emission regions render the typical edge-on disk extremely faint in the mid- and far- infrared. Infrared measurements are crucial for understanding the inner disk properties, for defining the wavelength where the SED transitions from scattered light to thermal emission, and for diagnosing the presence of large dust grains. We are currently carrying out a multiwavelength Hubble Space Telescope Cycle 14 imaging program studying 15 edge-on disks. A review of the Spitzer ROC shows that adequate MIPS and IRAC measurements already exist for the majority of the targets, but most of them have yet to be observed with IRS. We propose 11.5 hours of Spitzer observations to complete the infrared dataset for the known edge-on disks, primariliy IRS low-resolution spectroscopy, but also cleaning up the MIPS and IRAC results in a few cases. In combination with existing data, the results will provide a complete database of infrared SEDs and high spatial resolution optical/near-IR images for known edge-on disks. The resulting dataset will be a unique resource for modeling work on disk structure and dust grain evolution.

  20. Infrared color vision: separating objects from backgrounds

    NASA Astrophysics Data System (ADS)

    Scribner, Dean A.; Schuler, Jonathan; Warren, Penny; Satyshur, Michael; Kruer, Melvin R.

    1998-07-01

    The concept of multi-band infrared color vision is discussed in terms of combining two or more bands of infrared imagery into a single composite color image. This work is motivated by emerging new technologies in which two or more infrared bands are simultaneously imaged for improved discrimination of objects from backgrounds. One of the current objectives of this work is to quantify the improvement obtained over single band infrared imagery to detect dim targets in clutter. Methods are discussed for mapping raw image data into an appropriate color space and then processing it to achieve an intuitively meaningful color display for a human viewer. In this regard, the final imagery should provide good color contrast between objects and backgrounds and consistent colors regardless of environmental conditions such as solar illumination and variations in surface temperature. Initial performance measures show that infrared color can improve discrimination significantly over single band imaging.

  1. Faint extragalactic objects and the unidentified high latitude X-ray sources

    NASA Technical Reports Server (NTRS)

    Shulman, S.

    1979-01-01

    Classes of extragalactic objects that have been identified with faint high-galactic-latitude X-ray sources in the Fourth Uhuru and Ariel 5 Catalogs are examined. Sources with declinations of at least -30 deg, galactic latitudes of at least 20 deg (absolute value), and error boxes of 1.0 sq deg are considered. It is shown that clusters of galaxies constitute the most numerous class of extragalactic sources and that Seyfert galaxies are the next largest class. Unidentified high-latitude X-ray sources are discussed. Preliminary results obtained with the A-1 instrument aboard HEAO 1 are reported which indicate that a substantial fraction of unidentified sources are highly variable and may be identified with active galaxies.

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

    NASA Technical Reports Server (NTRS)

    Paresce, Francesco (editor)

    1990-01-01

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

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

    PubMed

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

    2010-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1982-06-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  8. Infrared-Faint Radio Sources: A Cosmological View - AGN Number Counts, the Cosmic X-Ray Background and SMBH Formation

    E-print Network

    Zinn, Peter-Christian; Ibar, Edo

    2011-01-01

    Context. Infrared Faint Radio Sources (IFRS) are extragalactic emitters clearly detected at radio wavelengths but barely detected or undetected at optical and infrared wavelengths, with 5 sigma sensitivities as low as 1 uJy. Aims. Recent SED-modelling and analysis of their radio properties shows that IFRS are consistent with a population of (potentially extremely obscured) high-redshift AGN at 3IFRS from four deep extragalactic surveys and extrapolated the IFRS number density to a survey-independent value of (30.8 +- 15.0) per square degree. We computed the IFRS contribution to the total number of AGN in the Universe to account for the Cosmic X-ray Background. By estimating the black hole mass contained in IFRS, we present conclusions for the SMBH mass density in the early universe and compare it to relevant simula...

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  10. Active galactic nuclei cores in infrared-faint radio sources. Very long baseline interferometry observations using the Very Long Baseline Array

    NASA Astrophysics Data System (ADS)

    Herzog, A.; Middelberg, E.; Norris, R. P.; Spitler, L. R.; Deller, A. T.; Collier, J. D.; Parker, Q. A.

    2015-06-01

    Context. Infrared-faint radio sources (IFRS) form a new class of galaxies characterised by radio flux densities between tenths and tens of mJy and faint or absent infrared counterparts. It has been suggested that these objects are radio-loud active galactic nuclei (AGNs) at significant redshifts (z ? 2). Aims: Whereas the high redshifts of IFRS have been recently confirmed based on spectroscopic data, the evidence for the presence of AGNs in IFRS is mainly indirect. So far, only two AGNs have been unquestionably confirmed in IFRS based on very long baseline interferometry (VLBI) observations. In this work, we test the hypothesis that IFRS contain AGNs in a large sample of sources using VLBI. Methods: We observed 57 IFRS with the Very Long Baseline Array (VLBA) down to a detection sensitivity in the sub-mJy regime and detected compact cores in 35 sources. Results: Our VLBA detections increase the number of VLBI-detected IFRS from 2 to 37 and provide strong evidence that most - if not all - IFRS contain AGNs. We find that IFRS have a marginally higher VLBI detection fraction than randomly selected sources with mJy flux densities at arcsec-scales. Moreover, our data provide a positive correlation between compactness - defined as the ratio of milliarcsec- to arcsec-scale flux density - and redshift for IFRS, but suggest a decreasing mean compactness with increasing arcsec-scale radio flux density. Based on these findings, we suggest that IFRS tend to contain young AGNs whose jets have not formed yet or have not expanded, equivalent to very compact objects. We found two IFRS that are resolved into two components. The two components are spatially separated by a few hundred milliarcseconds in both cases. They might be components of one AGN, a binary black hole, or the result of gravitational lensing.

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

    E-print Network

    Timothy Garn; Paul Alexander

    2008-09-24

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

  12. Morphological and Photometric Evolution of Ultraluminous Infrared Galaxies: The Nature of Faint SCUBA Sources

    Microsoft Academic Search

    Kenji Bekki; Yasuhiro Shioya; Ichi Tanaka

    1999-01-01

    We investigate when and how a dusty starburst galaxy merger can be heavily obscured by dust and consequently becomes an ultraluminous infrared galaxy (ULIRG), based on numerical simulations of chemodynamical and photometric evolution of dusty gas-rich major galaxy mergers. We found that a major galaxy merger is more likely to become a ULIRG preferentially in the merger late phase, when

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

    NASA Astrophysics Data System (ADS)

    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

    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).

  14. Morphological and photometric evolution of ultra-luminous infrared galaxies: Nature of faint SCUBA sources

    Microsoft Academic Search

    Kenji Bekki; Yasuhiro Shioya; Ichi Tanaka

    1999-01-01

    We investigate when and how a dusty starburst galaxy merger can be heavily\\u000aobscured by dust and consequently becomes an ultra-luminous infrared galaxy\\u000a(ULIRG), based on numerical simulations of chemodynamical and photometric\\u000aevolution of dusty gas-rich major galaxy mergers.\\u000a We found that a major galaxy merger is more likely to become an ULIRG\\u000apreferentially in the merger late phase, when

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

  16. Infrared-faint radio sources: a cosmological view. AGN number counts, the cosmic X-ray background and SMBH formation

    NASA Astrophysics Data System (ADS)

    Zinn, P.-C.; Middelberg, E.; Ibar, E.

    2011-07-01

    Context. Infrared-faint radio sources (IFRS) are extragalactic emitters clearly detected at radio wavelengths but barely detected or undetected at optical and infrared wavelengths, with 5? sensitivities as low as 1 ?Jy. Aims: Spectral energy distribution (hereafter SED) modelling and analyses of their radio properties indicate that IFRS are consistent with a population of (potentially extremely obscured) high-redshift AGN at 3 ? z ? 6. We demonstrate some astrophysical implications of this population and compare them to predictions from models of galaxy evolution and structure formation. Methods: We compiled a list of IFRS from four deep extragalactic surveys and extrapolated the IFRS number density to a survey-independent value of (30.8 ± 15.0) deg-2. We computed the IFRS contribution to the total number of AGN in the Universe to account for the cosmic X-ray background. By estimating the black hole mass contained in IFRS, we present conclusions for the SMBH mass density in the early universe and compare it to relevant simulations of structure formation after the Big Bang. Results: The number density of AGN derived from the IFRS density was found to be ~310 deg-2, which is equivalent to a SMBH mass density of the order of 103 M? Mpc-3 in the redshift range 3 ? z ? 6. This produces an X-ray flux of 9 × 10-16 W m-2 deg-2 in the 0.5-2.0 keV band and 3 × 10-15 W m-2 deg-2 in the 2.0-10 keV band, in agreement with the missing unresolved components of the Cosmic X-ray Background. To address SMBH formation after the Big Bang we invoke a scenario involving both halo gas accretion and major mergers.

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

    NASA Astrophysics Data System (ADS)

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

    1996-09-01

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

  18. Objects shape determination from a single infrared thermal image

    SciTech Connect

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

    1994-12-31

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

  19. Infrared Detection and Characterization of Near Earth Objects

    NASA Astrophysics Data System (ADS)

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

    1998-09-01

    Infrared detection from space offers an invaluable adjunct to ground based visible searches for the discovery and characterization of Near Earth Objects (NEOs). The known Near Earth Objects are predominately highly reflective, presumably due to a discovery bias against dark objects inherent in visual surveys. For a given diameter, dark objects are at least a factor of four fainter in the visual than those with high albedo. Various analyses argue that the population of dark objects among the NEOs should be at least as great as the highly reflective objects. In the mid-infrared (defined to be between 5 and 35 mu m) the flux difference between high and low albedo objects is relatively small, with slightly more flux coming from the dark object. Passive emission from objects located in the inner solar system peaks in the mid-infrared as the natural consequence of the object being in thermal equilibrium with the incident sunlight An infrared NEO survey compensates for the bias of visible searches to preferentially discover high albedo objects. Additionally, visual to infrared colors of NEOs are markedly different from those of most stars. This provides a basis for a bulk filter that significantly reduces the onboard signal processing requirements for a space-based system. Infrared observations also reduce the uncertainty in estimating the size, and subsequently the mass, of an NEO. A geometric albedo must be assumed in order to calculate a diameter from the single band visual photometry obtained during discovery or follow-up astrometry. The estimated size is thus quite uncertain owing to the order of magnitude range in NEO geometric albedos. The modeling assumptions needed to convert an infrared observation into a diameter are more tightly constrained. An infrared observation combined with visual photometry provides the requisite information to accurately determine both the albedo and size. Since the estimate of the NEO mass depends on volume, the determinations of NEO mass from infrared derived diameters are about an order of magnitude more certain than that estimated from visible photometry.

  20. Infrared Nebulae Around Young Stellar Objects

    E-print Network

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

    2006-11-20

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

  1. Cygnids and Taurids - Two classes of infrared objects.

    NASA Technical Reports Server (NTRS)

    Strecker, D. W.; Ney, E. P.; Murdock, T. L.

    1973-01-01

    In a study of the anonymous objects from the IRC Survey, we have found that about 10 percent have large long wave excesses. These infrared stars seem to belong to two classes, one group like NML Cygni (Cygnids) and the other like NML Tauri (Taurids).

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

    SciTech Connect

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

    2009-12-20

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

  3. Filling the infrared gap: ISO observations of 1 Jy BL Lacertae objects

    NASA Astrophysics Data System (ADS)

    Padovani, P.; Giommi, P.; Ábrahám, P.; Csizmadia, S.; Moór, A.

    2006-09-01

    Aims.The large majority of BL Lacertae objects belonging to the 1 Jy sample, the class prototype for radio-selected sources, are thought to emit most of their synchrotron power in the far infrared band. Ironically, this spectral region is very sparsely sampled, with only a minority of the objects having IRAS data (most of them being upper limits or low-quality detections). We aim at filling this infrared gap by presenting new, simultaneous ISOCAM and ISOPHOT observations over the 7-200~?m range (observer's frame) for half the sample. A precise measurement of the position of the synchrotron peak frequency, ?_peak, can provide direct information about particle acceleration mechanisms and constrain the inverse Compton radiation that will be detected by up-coming new ?-ray missions. Methods: .We have observed seventeen 1 Jy BL Lacertae objects with the camera and the photometer on board the Infrared Space Observatory (ISO) satellite. Given the intrinsic variability of these sources, the data were taken by concatenating the pointings to ensure simultaneity. The ISOPHOT data reduction was done employing a novel correction, which mitigates the effect of chopping for faint sources. Results: .Using our new ISO data, complemented by nearly-simultaneous radio and optical observations for ten and four objects respectively, and other multi-frequency data, we have built the spectral energy distributions of our sources (plus a previously published one) and derived the rest-frame ?_peak. Its distribution is centred at ˜ 1013 Hz (˜ 30~?m) and is very narrow, with ˜ 60% of the BL Lacs in the 1 - 3 × 1013 Hz range. Given our set of simultaneous infrared data, these represent the best determinations available of the synchrotron peak frequencies for low-energy peaked BL Lacs. A comparison with previous such estimates, based on non-simultaneous optical and near infrared data, may indicate strong ?_peak variations in a number of sources, possibly associated with large flares as observed in the high-energy peaked BL Lac MKN 501.

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

    E-print Network

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

    2002-03-22

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

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

    SciTech Connect

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

    2011-05-01

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

  6. Pyroelectric infrared sensor-based thermometer for monitoring indoor objects

    NASA Astrophysics Data System (ADS)

    Tsai, C. F.; Young, M. S.

    2003-12-01

    This article describes a system for measuring temperature by monitoring an object's radiation in the infrared spectrum. Using a measuring device by passing through a data acquisition interface, a long-term observation of the temperature variance of objects on a personal computer by the LabVIEW software is conducted. A special mechanism joined with a pyroelectric infrared (PIR) sensor, optical chopper, and Fresnel lens is presented in this system. This separable architecture makes the lens easily replaceable and portable. In this study, the PIR sensor into a quantitative measurement for long-term and long-distance applications with calibration equipment based on a blackbody and some electrometers was successfully applied. Experimental results show that the measuring device only has an average error rate of 1.21% in the overall range from 40 to 200 °C, and field of view is 4.58°. The results confirm that noncontacted temperature measurement using a PIR sensor is feasible.

  7. Mid-Infrared Imaging of Young Stellar Objects

    E-print Network

    Michael C. Liu; James R. Graham; A. M. Ghez; M. Meixner; C. J. Skinner; Eric Keto; Roger Ball; J. F. Arens; J. G. Jernigan

    1995-10-18

    We present arcsecond resolution mid-infrared (8--13 $\\mu$m) images and photometry of four young stellar objects (YSOs)~--- L1551-IRS5, HL~Tau, AS~205, and AS~209 (V1121~Oph)~--- taken with the Berkeley Mid-Infrared Camera. For AS~205, a known T Tauri binary, we also present near-infrared JHK images and HKL$^{\\prime}$ speckle imaging data. All three single stars are unresolved in our mid-IR images. Our data is the first to resolve in the mid-IR both components of the close binary AS~205 (projected separation $\\sim$1.3$^{\\prime \\prime}$ (210~A.U.)). AS~205~North is the IR brighter star in our data while published observations find it to be the optically fainter star. Pre-main sequence evolutionary models suggest the AS~205 system is non-coeval; we discuss possible explanations for this result and comment on the circumstellar material and evolutionary status of this young binary. Nearly all of our objects exhibit changes in their mid-IR flux in measurements separated by intervals of days up to many years; the variations range from 30--300\\%. We speculate that the cause of the variability lies in the accretion disks of these objects; the data suggest disk accretion rate fluctuations of nearly an order of magnitude. The existence of large mid-IR variability argues that simultaneous multiwavelength observations are needed for a proper analysis of YSO spectral energy distributions.

  8. 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)

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

    1994-01-01

    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.

  9. Mid-infrared imaging of young stellar objects

    E-print Network

    Liu, M C; Ghez, A M; Meixner, M; Skinner, C J; Keto, E; Ball, R; Arens, J; Jernigan, J G; Liu, Michael C; Graham, James R; Keto, Eric; Ball, Roger

    1995-01-01

    We present arcsecond resolution mid-infrared (8--13 \\mum) images and photometry of four young stellar objects (YSOs)~--- L1551-IRS5, HL~Tau, AS~205, and AS~209 (V1121~Oph)~--- taken with the Berkeley Mid-Infrared Camera. For AS~205, a known T Tauri binary, we also present near-infrared JHK images and HKL^{\\prime} speckle imaging data. All three single stars are unresolved in our mid-IR images. Our data is the first to resolve in the mid-IR both components of the close binary AS~205 (projected separation \\sim1.3^{\\prime \\prime} (210~A.U.)). AS~205~North is the IR brighter star in our data while published observations find it to be the optically fainter star. Pre-main sequence evolutionary models suggest the AS~205 system is non-coeval; we discuss possible explanations for this result and comment on the circumstellar material and evolutionary status of this young binary. Nearly all of our objects exhibit changes in their mid-IR flux in measurements separated by intervals of days up to many years; the variations...

  10. Visible and Near Infrared colors of Trans-neptunian Objects

    NASA Astrophysics Data System (ADS)

    Doressoundiram, Alain; Peixinho, N.

    2007-10-01

    We present the latest results of the Meudon Multicolor survey (2MS). This survey aimed at characterizing the colors properties and trends of Centaurs and Trans-Neptunian Objects. We report IJHK photometry of objects obtained with CFHT-IR at the Canada-France-Hawaii 3.6-m Telescope (CFHT, Hawaii), JHK photometry with INGRID at the William Hershel 4.2-m Telescope (WHT, La Palma), and BVRI photometry with OIG at the Telescopio Nazionale Galileo 3.6-m Telescope (TNG, La Palma). Combined with our previous visible colors, we have obtained quasi simultaneous visible-near-infrared colors for 38 objects. This large sample allows an extended characterization of the colors properties of these primitive objects from the B (0.4 µm) to the K (2.2 µm) regime. Together with all the other infrared color published, we performed a detailed statistical analysis in order to search for significant trends. The most relevant conclusion about visible and near-IR color-color correlations is that, basically, JHK bands alone do not evidence correlations, neither between them nor with BVRIJ bands. Only Centaurs show an anti-correlation between visible colors and H-K. Colors within each dynamical family compare very similarly. All the results will be presented and discussed. NP acknowledges funding from the European Social Fund and the Portuguese Foundation for Science and Technology (ref: BPD/18724/2004).

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

    SciTech Connect

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

    1990-07-01

    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.

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

    E-print Network

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

    2002-01-01

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

  13. Mid-infrared imaging of young stellar objects

    SciTech Connect

    Liu, M.C.; Graham, J.R. [Department of Astronomy, University of California, Berkeley, California 94720 (United States)] [Department of Astronomy, University of California, Berkeley, California 94720 (United States); Ghez, A.M. [Department of Astronomy, University of California, Los Angeles, California 90024 (United States)] [Department of Astronomy, University of California, Los Angeles, California 90024 (United States); Meixner, M. [Department of Astronomy, University of Illinois, Urbana-Champaign, Illinois 61801 (United States)] [Department of Astronomy, University of Illinois, Urbana-Champaign, Illinois 61801 (United States); Skinner, C.J.; Keto, E.; Ball, R. [Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Arens, J.F.; Jernigan, J.G. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)] [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)

    1996-04-01

    We present arcsecond resolution mid-infrared (8{endash}13 {mu}m) images and photometry of four young stellar objects (YSOs){emdash}L1551-IRS 5, HL Tau, AS 205, and AS 209 (V1121 Oph){emdash}taken with the Berkeley Mid-Infrared Camera. For AS 205, a known T Tauri binary, we also present near-infrared {ital JHK} images and {ital HKL}{prime} speckle imaging data. All three single stars are unresolved in our mid-IR images, consistent with current models of the circumstellar material associated with these objects. Our data are the first to resolve in the mid-IR both components of the close binary AS 205 (projected separation {approximately}1{center_dot}{double_prime}3 [210 AU]). Both stars are classical T Tauri stars and possess the 9.7 {mu}m silicate feature in emission. AS 205 North is the IR brighter star in our data, while published observations find it to be the optically fainter star. Assuming that the IR excesses of both components arise from circumstellar disks, we find the emitting regions (the inner few AU) of the disks to be optically thick in the mid-IR. Pre-main-sequence evolutionary models suggest that the AS 205 system is non-coeval; we discuss possible explanations for this result and comment on the evolutionary status of this young binary. All our objects, except perhaps AS 205 South, exhibit changes in their mid-IR flux in measurements separated by intervals of days up to many years; the variations range from 30{percent}{endash}300{percent}. For the classical T Tauri stars AS 205 North and AS 209, the magnitude of the changes seems to discount the possibility that the mid-IR variations have the same origin as the optical and near-IR variability of T Tauri stars, namely, accretion-related features on or near the stellar photosphere. We speculate that the cause of the variability lies in the accretion disks of these objects; the data suggest disk accretion rate fluctuations of nearly an order of magnitude. (Abstract Truncated)

  14. Object Tracking using Joint Visible and Thermal Infrared

    E-print Network

    Boyer, Edmond

    the color and the infrared modal- ities. As the infrared and the visible image sequences are acquired of the modality. Our cooperative tracking method is successfully applied on several experimental datasets of the infrared modality, or tracking in the infrared with the help of the visible modality. Comments and future

  15. Dizziness and Fainting Spells

    MedlinePLUS

    Healthy Children > Health Issues > Conditions > Head Neck & Nervous System > Dizziness and Fainting Spells Health Issues Listen Español Text Size Email Print Share Dizziness and Fainting Spells Article Body ...

  16. A MID-INFRARED IMAGING SURVEY OF EMBEDDED YOUNG STELLAR OBJECTS IN THE OPHIUCHI CLOUD CORE

    E-print Network

    Barsony, Mary

    A MID-INFRARED IMAGING SURVEY OF EMBEDDED YOUNG STELLAR OBJECTS IN THE OPHIUCHI CLOUD CORE Mary 2005 April 18 ABSTRACT Results of a comprehensive, new, ground-based mid-infrared imaging survey infall envelopes. Mid-infrared variability is found among a significant fraction of the surveyed objects

  17. Rapid response near-infrared spectrophotometric characterization of Near Earth Objects

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  18. OPTICAL-FAINT, FAR-INFRARED-BRIGHT HERSCHEL SOURCES IN THE CANDELS FIELDS: ULTRA-LUMINOUS INFRARED GALAXIES AT z > 1 AND THE EFFECT OF SOURCE BLENDING

    SciTech Connect

    Yan, Haojing; Stefanon, Mauro; Ma, Zhiyuan [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); Willner, S. P.; Ashby, Matthew L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Somerville, Rachel [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Davé, Romeel [University of the Western Cape, 7535 Bellville, Cape Town (South Africa); Pérez-González, Pablo G. [Departamento de Astrofísica, Facultad de CC. Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Cava, Antonio [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Versoix (Switzerland); Wiklind, Tommy [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Kocevski, Dale [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Rafelski, Marc [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Kartaltepe, Jeyhan [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Koekemoer, Anton M.; Grogin, Norman A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-07-01

    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 {sub 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 {sub 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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  20. Object tracking in a stereo and infrared vision system

    NASA Astrophysics Data System (ADS)

    Colantonio, S.; Benvenuti, M.; Di Bono, M. G.; Pieri, G.; Salvetti, O.

    2007-01-01

    In this paper, we deal with the problem of real-time detection, recognition and tracking of moving objects in open and unknown environments using an infrared (IR) and visible vision system. A thermo-camera and two stereo visible-cameras synchronized are used to acquire multi-source information: three-dimensional data about target geometry and its thermal information are combined to improve the robustness of the tracking procedure. Firstly, target detection is performed by extracting its characteristic features from the images and then by storing the computed parameters on a specific database; secondly, the tracking task is carried on using two different computational approaches. A Hierarchical Artificial Neural Network (HANN) is used during active tracking for the recognition of the actual target, while, when partial occlusions or masking occur, a database retrieval method is used to support the search of the correct target followed. A prototype has been tested on case studies regarding the identification and tracking of animals moving at night in an open environment, and the surveillance of known scenes for unauthorized access control.

  1. Alignment and performance of the Infrared Multi-Object Spectrometer

    NASA Astrophysics Data System (ADS)

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

    2003-10-01

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

  2. The Sandage Two-color (U,B) Survey of the Galactic Plane: Status Report on the Continuing Search for Faint UV-Bright Objects

    NASA Astrophysics Data System (ADS)

    Lanning, H. H.; Meakes, M.

    1998-05-01

    The examination of the Sandage two-color photographic survey of the galactic plane taken in support of the Uhuru X-ray satellite project (1969-1972) has continued and has produced more than 300 new faint UV-bright sources within the past two years. Two new DA white dwarfs were confirmed in March by Deutsch and Margon from the latest published list. White dwarfs, CVs and suspected novae are just a few of the types of interesting objects being found in this deep (B = 20+ limiting magnitude) and extensive survey. The initial intent of the survey was to identify and study the optical counterparts of newly detected x-ray sources. More than 100 6.6deg x 6.6deg plates were taken with the Palomar 48-in. Oschin Schmidt telescope. No optical identifications were successfully made, due in large part to the poor positional accuracy of the x-ray sources determined by Uhuru. Visual examination of a selected sample of the double-exposed U and B plates did, however, result in the identification of a number of interesting objects including a new cataclysmic variable, a new DO white dwarf and several peculiar objects. The potential for the identification of low-luminosity stars, binary systems and old novae was clear thus supporting the continuation of the analysis. In recent years, three additional catalog listings have been published and a fifth is nearing completion. Several new white dwarfs, potential old novae and variable stars, as well as another CV, have been subsequently identified. We present in this poster paper a review of the survey project and analysis and provide an update on the current status of the overall project.

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

    SciTech Connect

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

    2011-04-01

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

  4. Kinematics of faint white dwarfs.

    PubMed

    Luyten, W J

    1978-10-01

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

  5. 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)

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

    1996-01-01

    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.

  6. Detecting buried objects by fusing dual-band infrared images

    Microsoft Academic Search

    Gregory A. Clark; Sailes K. Sengupta; Michael R. Buhl; Robert J. Sherwood; Paul C. Schaich; Nathan Bull; Ronald J. Kane; Marvin J. Barth; David J. Fields; Michael R. Carter

    1993-01-01

    The authors 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, the paper focuses on the

  7. Herbig-haro objects and mid-infrared outflows in the VELA C molecular cloud

    SciTech Connect

    Zhang, Miaomiao; Wang, Hongchi [Purple Mountain Observatory, and Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008 (China); Henning, Thomas, E-mail: miaomiao@pmo.ac.cn [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-08-01

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

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

    E-print Network

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

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

    PubMed

    Sadjadi, Firooz A; Chun, Cornell S L

    2003-04-01

    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

  10. Design of polarized infrared athermal telephoto objective for penetrating the fog

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  11. The optical spectra of Spitzer 24 micron galaxies in the COSMOS field: II. Faint infrared sources in the zCOSMOS-bright 10k catalogue

    E-print Network

    Caputi, K I; Aussel, H; Le Floc'h, E; Sanders, D; Maier, C; Frayer, D; Carollo, C M; Contini, T; Kneib, J -P; Le Fèvre, O; Mainieri, V; Renzini, A; Scodeggio, M; Scoville, N; Zamorani, G; Bardelli, S; Bolzonella, M; Bongiorno, A; Coppa, G; Cucciati, O; De la Torre, S; de Ravel, L; Franzetti, P; Garilli, B; Ilbert, O; Iovino, A; Kampczyk, P; Kartaltepe, J; Knobel, C; Kovac, K; Lamareille, F; Le Borgne, J F; Le Brun, V; Mignoli, M; Peng, Y; Pérez-Montero, E; Ricciardelli, E; Salvato, M; Silverman, Joseph; Surace, J; Tanaka, M; Tasca, L; Tresse, L; Vergani, D; Zucca, E; Abbas, U; Bottini, D; Capak, P; Cappi, A; Cassata, P; Cimatti, A; Elvis, M; Hasinger, G; Koekemoer, A M; Leauthaud, A; MacCagni, D; Marinoni, C; McCracken, H; Memeo, P; Meneux, B; Oesch, P; Pellò, R; Porciani, C; Pozzetti, L; Scaramella, R; Scarlata, C; Schiminovich, D; Taniguchi, Y; Zamojski, M

    2009-01-01

    We have used the zCOSMOS-bright 10k sample to identify 3244 Spitzer/MIPS 24-micron-selected galaxies with 0.06< S(24um)< 0.50 mJy and I(AB)<22.5, over 1.5 deg^2 of the COSMOS field, and studied different spectral properties, depending on redshift. At 0.2infrared (IR) sources, within the error bars. For up to 16% of objects, instead, the Halpha/Hbeta ratios are too high for their IR/UV attenuations, which is probably a consequence of inhomogenous dust distributions. In only a few of our galaxies at 0.2

  12. Herbig-Haro objects and mid-infrared outflows in the Vela C molecular cloud

    E-print Network

    Zhang, Miaomiao; Henning, Thomas

    2014-01-01

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

  13. The HST quasar absorption line key project. 4: HST faint-object spectrograph and ground-based observations of the unusual low-redshift broad absorption-line quasi-stellar object PG 0043+039

    NASA Technical Reports Server (NTRS)

    Turnshek, David A.; Espey, Brian R.; Kopko, Michael, Jr.; Rauch, Michael; Weymann, Ray J.; Jannuzi, Buell T.; Boksenberg, Alec; Bergeron, Jacqueline; Hartig, George F.; Sargent, W. L. W.

    1994-01-01

    Hubble Space Telescope Faint Object Spectrograph (HST FOS) observations have shown that the spectrum of the low-redshift (z(sub em) approximately equal to 0.384) QSO PG 0043+039 exhibits weak broad absorption lines (BALs). The BALs were discovered during the course of UV spectrophotometry made for the HST Quasar Absorption Line Key Project. The HST data are analyzed along with ground-based optical and IUE spectrophotometry. The object is found to have a number of atypical properties relative to normal non-BAL QSOs. The observed continuum is atypical in the sense that it is much weaker than that of a normal optically selected QSO at rest wavelengths approximately less than 2200 A. Intrinsic reddening of E(B-V) approximately equal to 0.11 mag by dust similar to that found in the SMC at the redshift of PG 0043+039 conservatively accounts for the observed continuum shape moderately well. These observed characteristics are typical of low-ionization BAL QSOs, but convincing evidence for BALs due to low-ionization transitions of Mg II, Al III, Al II, or C II does not exist. Therefore, this object may be a misaligned BAL QSO having many of the characteristics of low-ionization BAL QSOs with the sight line passing through a putative dusty region, but evidently missing clouds of high enough column density to produce observable low-ionization BALs. If the intrinsic dust-extinction model is correct, the observations suggest that the dust is not confined to the presumably higher density, low-ionization BAL clouds, but that it has drifted to nearby high-ionization BAL regions. We also consider other possible mechanisms for producing the shape of the continuous energy distribution which cannot be ruled out. We compare the Fe II emission in PG 0043+039 with that in another Key Project QSO, NGC 2841-UB 3, which has optical Fe II emission comparable in strength to that in PG 0043+039, but has anomalously weak UV Fe II emission. In addition, from an analysis of UV and optical spectrophotometric data at 5 epochs over approximately 11 yr, there is tentative evidence that PG 0043+039 has varied in brightness by as much as 1.1 mag during this time interval. Two different interpretations of PG 0043+039 and the low-ionization BAL QSOs are considered. Various model scenarios for explaining the weak narrow-line (O III) emission are considered, but there is no definitive explanation.

  14. Spatiotemporal saliency model for small moving object detection in infrared videos

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Ning, Chen; Xu, Lizhong

    2015-03-01

    In this paper, a novel spatiotemporal saliency model based on three-dimensional Difference-of-Gaussians filters is proposed for small moving object detection in infrared videos. First, instead of utilizing the spatial Difference-of-Gaussians (DoG) filter which has been used to build saliency model for static images, we propose to extend the spatial DoG filter to construct three-dimensional (3D) Difference-of-Gaussians filters for measuring the center-surround difference in the spatiotemporal receptive field. Second, an effective spatiotemporal saliency model is generated based on these filters. This model provides a good basis for accurate and robust infrared small moving object detection. Experimental results show that the proposed saliency model consistently outperforms state-of-the-art saliency models for infrared moving object detection under various complex backgrounds.

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

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1995-01-01

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

  16. Research and development of infrared object detection system based on FPGA

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    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.

  17. Moving Object Detection and Tracking in Forward Looking InfraRed Aerial Imagery

    Microsoft Academic Search

    Subhabrata Bhattacharya; Imran Saleemi; Mubarak Shah

    2011-01-01

    This chapter discusses the challenges of automating surveillance and reconnaissance tasks for infra-red visual data obtained from aerial platforms. These problems have gained significant importance over the years, especially with the advent of light weight and reliable imaging devices. Detection and tracking of objects of interest has traditionally been an area of interest in the computer vision literature. These tasks

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

    Microsoft Academic Search

    Bahram Mobasher; David Crampton; Luc Simard

    2010-01-01

    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,

  19. Performance modeling of JWST near-infrared multi-object spectrograph

    Microsoft Academic Search

    Frédéric Zamkotsian; Kjetil Dohlen

    2004-01-01

    The James Webb Space Telescope (JWST) will be equipped with a Near Infrared Multi-Object Spectrograph (NIRSpec), in order to record simultaneously several hundred spectra in a single observation run. The selection of the objects in the field of view will be done by a micro-elecro-mechanical system (MEMS): a micro-shutter array. This array is easily reconfigurable and can generate any slit

  20. Star formation in Taurus. I - The IRAS Faint Source Survey

    NASA Technical Reports Server (NTRS)

    Beichman, C. A.; Boulanger, F.; Moshir, M.

    1992-01-01

    A deep infrared survey of a 187 sq deg region in Taurus using the IRAS Faint Source Survey reveals 63 multiband objects selected on the basis of their infrared properties. Two-thirds of the sample are previously uncataloged and are most likely either deeply embedded objects or unidentified T Tauri stars. Complete IRAS data are presented for these objects. The sample is estimated to be more than 90 percent complete for objects emitting L equal to or greater than 0.1 solar luminosity between 12 and 60 microns. The luminosity function shows a decline at luminosities below 0.3 solar luminosity. The formation of a massive, 0.1 solar mass, disk of circumstellar material serving as a reservoir for infalling cloud material represents a possible resolution of the problem. A population of unresolved sources emitting only at 60 microns is also identified. If any of these objects are self-luminous, they may represent the youngest protostellar objects yet observed.

  1. OH-selected AGB and post-AGB objects I.Infrared and maser properties

    Microsoft Academic Search

    Maartje N. Sevenster

    2002-01-01

    Using 766 compact objects from a survey of the galactic Plane in the 1612-MHz\\u000aOH line, new light is cast on the infrared properties of evolved stars on the\\u000aTP-AGB and beyond. The usual mid-infrared selection criteria, based on IRAS\\u000acolours, largely fail to distinguish early post-AGB stages. A two-colour\\u000adiagram from narrower-band MSX flux densities, with bimodal distributions,\\u000aprovides

  2. Building Facade Object Detection from Terrestrial Thermal Infrared Image Sequences Combining Different Views

    NASA Astrophysics Data System (ADS)

    Hoegner, L.; Stilla, U.

    2015-03-01

    This paper discusses the automatic texturing of building facades from thermal infrared image sequences. A fully automatic method is presented to refine GPS based positions estimating relative orientations of the image sequences including a given building model in a bundle adjustment process. The resulting refined orientation parameters are used to extract partial facade textures from all images and all sequences. The resulting partial textures of every sequence are combined to get complete facade textures in the thermal infrared domain. Textures from different image sequences are combined for object detection and extraction. These sequences are acquired either at different times for different radiometric thermal behavior of facade objects or with different viewing directions for objects located before or behind the facade plane.

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

    E-print Network

    Alberto Noriega-Crespo

    2001-01-04

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

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  5. Near-infrared (JHK) spectroscopy of young stellar and substellar objects in orion

    SciTech Connect

    Ingraham, P.; Albert, L.; Doyon, R.; Artigau, E. [Département de Physique, Université de Montréal, Montréal PQ H3T1J4 (Canada)

    2014-02-10

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

  6. Object recognition in infrared image sequences using scale invariant feature transform

    Microsoft Academic Search

    Kyung-hoon Bae; Jik-Han Jung

    2008-01-01

    In this paper, we propose an automated target recognition by using scale-invariant feature transform (SIFT) in PowerPC-based infrared (IR) imaging system. An IR image can be acquired more feature values at night than in the daytime, but visual image can be acquired more feature values in the daytime. IR-based object recognition puts application into digital surveillance system because it exist

  7. High-resolution algorithms for locating closely spaced objects via infrared focal-plane arrays

    Microsoft Academic Search

    Yasemin C. Yardimci; James A. Cadzow

    1994-01-01

    The location of a single point source in infrared imaging is typically achieved through conventional methods such as centroiding. More challenging problems with multiple point sources require alternative location-finding methods with the potential of resolving closely spaced objects. The authors introduce an algorithm predicated on least-squared-error (LSE) modeling with a Gram-Schmidt orthogonalization step. Its noise performance is compared with two

  8. Object Outline and Surface-Trace Detection Using Infrared Proximity Array

    Microsoft Academic Search

    Ákos Tar; György Cserey

    2011-01-01

    In this paper, a method of detecting object outlines and creating surface traces using a low-cost distance measurement array of infrared light-emitting diode (LED)-photodiode pairs is demonstrated. For each active LED, the light level on the corre- sponding photodiode may be measured, generating an image of distance values whose pixel resolution is limited to the spacing be- tween LED-photodiode pairs.

  9. Infrared-Excess Stellar Objects in the Supernova Remnant G54.1+0.3

    NASA Astrophysics Data System (ADS)

    Koo, Bon-Chul

    2012-01-01

    We propose COMICS N- and Q-band imaging observations of infrared-excess stellar objects in G54.1+0.3. G54.1+0.3 is a young supernova remnant (SNR) which has recently attracted considerable interest by its associated infrared (IR) loop and embedded stellar sources discovered by AKARI and Spitzer infrared space telescopes. Two scenarios have been proposed for the relation between the stellar sources with IR excess and the SNR: (i) the stellar sources are young massive stellar objects whose formation was triggered by the progenitor of the SNR, and the IR-excess emission is from their circumstellar material, (ii) the stellar sources are massive stars in a cluster to which the progenitor of the SNR belonged, and the IR-excess emission is from the supernova ejecta dusts. The COMICS silicate filter sets provide sufficient sensitivity and spectral resolution to derive the exact shape of spectra, which together with the Q-band photometry will reveal the nature of dusts in this intriguing object. We also propose [Ne II] and Q-band imaging observations of the brightest compact source in the IR loop to investigate the spatial correlation between the SN ejecta and dusts, which is essential to understand the nature of this compact source.

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

    E-print Network

    Joana M. Oliveira; Jacco Th. van Loon

    2004-02-03

    We present new mid-infrared observations of objects in the vicinity of the O-star sigma Orionis, obtained with TIMMI-2 at ESO. By constraining their near- and mid-infrared spectral energy distributions, we established the nature of previously known IRAS sources and identified new mid-infrared sources as young stellar objects with circumstellar disks, likely massive members of the sigma Ori cluster. For two of these objects we have obtained spectroscopy in the 8-13 micron range in order to investigate the chemistry of the dust grains. TX Ori exhibits a typical silicate emission feature at 10 micron, with a feature at about 11.2 micron that we identify as due to crystalline olivine. The IRAS 05358-0238 spectrum is very unusual, with a weak silicate feature and structure in the range 10-12 micron that may be explained as due to self-absorbed forsterite. We also provide the first evidence for the presence of circumstellar disks in the jet sources Haro 5-39/HH 447, V510 Ori/HH 444 and V603 Ori/HH 445.

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

    E-print Network

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

    2000-04-20

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

  12. Faint Photometric Standard Fields for HST

    Microsoft Academic Search

    Brad Whitmore; Abi Saha; Peter Stetson; Stefano Casertano; Ralph Bohlin

    2000-01-01

    Some of the most important projects with the most expensive telescope ever built - HST - are hostage to the uncertainty in the absolute calibration of its photometric system. The standard practice in the past has been to calibrate faint objects observed with long exposures against bright stars observed with very short exposures. There is now good evidence that this

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

    E-print Network

    V. Straizys; V. Laugalys

    2008-03-17

    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.

  14. Faint dwarfs in nearby groups

    SciTech Connect

    Speller, Ryan; Taylor, James E., E-mail: rspeller@uwaterloo.ca, E-mail: taylor@uwaterloo.ca [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada)

    2014-06-20

    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 ?m{sub r} ? (m{sub r,} {sub sat} – m{sub r,} {sub 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 ?m{sub r} = 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.

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

    SciTech Connect

    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

    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.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  17. Near-Infrared Spectroscopy and Hubble Space Telescope Imaging of a Dusty Starburst Extremely Red Object

    NASA Astrophysics Data System (ADS)

    Smith, Graham P.; Treu, Tommaso; Ellis, Richard; Smail, Ian; Kneib, J.-P.; Frye, B. L.

    2001-12-01

    We present near-infrared spectroscopy and Hubble Space Telescope (HST) imaging of ERO J164023+4644, an Extremely Red Object (ERO) with (R-K)=5.9 at z=1.05 that has been detected by Infrared Space Observatory (ISO) at 15 ?m. ERO J164023 resembles a disk galaxy, with an optical/infrared spectral energy distribution that is strongly reddened by dust (LFIR/LB<~200 AV~5). The combination of the narrow width of the emission lines in our spectra (~300 km s-1) and the relatively high [N II]/H? line ratio indicate that this is a ``composite'' starburst-Seyfert galaxy. Assuming that star formation dominates the energy output, we constrain the star formation rate to lie in the broad range ~10-700 Msolar yr-1 from a variety of star formation indicators. We compare ERO J164023 with the only other spectroscopically identified dusty EROs: HR10 (z=1.44) and ISO J1324-2016 (z=1.50). ERO J164023 and HR10 have similar disklike morphologies in the rest-frame UV, and both exhibit a variation in the apparent dust obscuration depending upon the diagnostic used, which suggests that there is a complex spatial mix of stellar populations and dust in these galaxies. In contrast, the compact morphology and spectral properties of ISO J1324-2016 indicate that it is a dusty quasar. Overall, our results demonstrate that the population of dusty galaxies identified using photometric ERO criteria includes systems ranging from pure starbursts through transition systems, such as ERO J164023, to dusty quasars. We suggest that the classification of EROs into these subclasses, necessary for the detailed modeling of the population, cannot be reliably achieved from optical/near-infrared photometry and instead requires mid/far-infrared or submillimeter photometry and near-infrared spectroscopy. The advent of efficient multiobject spectrographs working in the near-infrared, as well as the imminent launch of SIRTF, therefore promises the opportunity of rapid progress in our understanding of the elusive ERO population. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

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

    E-print Network

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

    1999-09-07

    We describe an object in the Hubble Deep Field North with very unusual near-infrared properties. It is readily visible in Hubble Space Telescope NICMOS images at 1.6um and from the ground at 2.2um, but is undetected (with signal-to-noise ~ 8.3 (97.7% confidence) from 1.6 to 1.1um. The object is compact but may be slightly resolved in the NICMOS 1.6um image. In a low-resolution, near-infrared spectrogram, we find a possible emission line at 1.643um, but a reobservation at higher spectral resolution failed to confirm the line, leaving its reality in doubt. We consider various hypotheses for the nature of this object. Its colors are unlike those of known galactic stars, except perhaps the most extreme carbon stars or Mira variables with thick circumstellar dust shells. It does not appear to be possible to explain its spectral energy distribution as that of a normal galaxy at any redshift without additional opacity from either dust or intergalactic neutral hydrogen. The colors can be matched by those of a dusty galaxy at z >~ 2, by a maximally old elliptical galaxy at z >~ 3 (perhaps with some additional reddening), or by an object at z >~ 10 whose optical and 1.1um light have been suppressed by the intergalactic medium. Under the latter hypothesis, if the luminosity results from stars and not an AGN, the object would resemble a classical, unobscured protogalaxy, with a star formation rate >~ 100 M_sun/yr. Such UV-bright objects are evidently rare at 2 < z < 12.5, however, with a space density several hundred times lower than that of present-day L* galaxies.

  19. Characterization of high proper motion objects from the wide-field infrared survey explorer

    SciTech Connect

    Luhman, K. L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Sheppard, Scott S., E-mail: kluhman@astro.psu.edu [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States)

    2014-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  1. MOIRCS: Multi-Object Infrared Camera and Spectrograph for the Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Tokoku, Chihiro; Suzuki, Ryuji; Ichikawa, Takashi; Asai, Ken'ichiro; Katsuno, Yuka; Omata, Koji; Yamada, Toru; Sasaki, Atsuo; Nishimura, Tetsuo

    2003-03-01

    MOIRCS (Multi-Object InfraRed Camera and Spectrograph) is one of the second generation instruments for the Subaru Telescope. This instrument is under construction by the National Astronomical Observatory of Japan and Tohoku University. It has imaging and multi-object spectroscopy (MOS) capabilities in the wavelength range from 0.85 ?m to 2.5 ?m with 4' x 7' F.O.V. The focal plane is imaged onto two 2048 x 2048 pixel HAWAII-2 HgCdTe arrays with a pixel scale of 0."12 pixel-1 through two independent optical trains. The optical design is optimized to maximize K band performance. Unique design of MOIRCS allows multi-object spectroscopy out to K band with cooled multi-slit masks. Twenty-four masks are stored in a mask dewar and are exchanged in the cryogenic environment. The mask dewar has its own vacuum pump and cryogenic cooler, and the masks can be assessed without breaking the vacuum of the main dewar. The two-channel optics and arrays are mounted back-to-back of a single optical bench plate. A PC-Linux based infrared array control system has been prepared to operate HAWAII-2. The first light of MOIRCS is planned in the spring of 2003.

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

    NASA Astrophysics Data System (ADS)

    Rockley, Graham J.

    2001-03-01

    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.

  3. The Hubble Space Telescope Wide Field Camera 3 Early Release Science data: Panchromatic Faint Object Counts from 0.2-2 microns wavelength

    E-print Network

    Windhorst, Rogier A; Hathi, Nimish P; McCarthy, Patrick J; Ryan, Russell E; Jr.,; Yan, Haojing; Baldry, Ivan K; Driver, Simon P; Frogel, Jay A; Hill, David T; Kelvin, Lee S; Koekemoer, Anton M; Mechtley, Matt; O'Connell, Robert W; Robotham, Aaron S G; Rutkowski, Michael J; Seibert, Mark; Tuffs, Richard J; Balick, Bruce; Bond, Howard E; Bushouse, Howard; Calzetti, Daniela; Crockett, Mark; Disney, Michael J; Dopita, Michael A; Hall, Donald N B; Holtzman, Jon A; Kaviraj, Sugata; Kimble, Randy A; MacKenty, John W; Mutchler, Max; Paresce, Francesco; Saha, Abihit; Silk, Joseph I; Trauger, John; Walker, Alistair R; Whitmore, Bradley C; Young, Erick

    2010-01-01

    We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Release Science (ERS) observations in the Great Observatories Origins Deep Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, drizzled mosaics in the mid-UV filters F225W, F275W, and F336W, as well as in the near-IR filters F098W (\\Ys), F125W (J), and F160W (H) in 1-2 HST orbits per filter. Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South mosaics in the BVi'z' filters, these panchromatic 10-band ERS data cover 40-50 square arcmin from from 0.2-1.7 \\mum\\ in wavelength at 0\\arcspt 07-0\\arcspt 15 FWHM resolution and 0\\arcspt 090 multidrizzled pixels to depths of AB\\cle 26.0-27.0 mag (5-sigma) for point sources, and AB\\cle 25.5-26.5 mag for compact galaxies. In this paper, we describe: a) the scientific rationale, and the data taking plus reduction procedures of the panchromatic 10-band ERS mosaics; b) the procedure of generating object catalogs across the 10 different ERS filters, and the ...

  4. The Remarkable Mid-Infrared Jet of Massive Young Stellar Object G35.20-0.74

    E-print Network

    James M. De Buizer

    2006-03-16

    The young massive stellar object G35.20-0.74 was observed in the mid-infrared using T-ReCS on Gemini South. Previous observations have shown that the near infrared emission has a fan-like morphology that is consistent with emission from the northern lobe of a bipolar radio jet known to be associated with this source. Mid-infrared observations presented in this paper show a monopolar jet-like morphology as well, and it is argued that the mid-infrared emission observed is dominated by thermal continuum emission from dust. The mid-infrared emission nearest the central stellar source is believed to be directly heated dust on the walls of the outflow cavity. The hydroxyl, water, and methanol masers associated with G35.20-0.74 are spatially located along these mid-infrared cavity walls. Narrow jet or outflow cavities such as this may also be the locations of the linear distribution of methanol masers that are found associated with massive young stellar objects. The fact that G35.20-0.74 has mid-infrared emission that is dominated by the outflow, rather than disk emission, is a caution to those that consider mid-infrared emission from young stellar objects as only coming from circumstellar disks.

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

    SciTech Connect

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

    2010-10-20

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

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

    SciTech Connect

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

    2012-05-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

  8. Object recognition in infrared image sequences using scale invariant feature transform

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

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

  9. Fainting attacks in children.

    PubMed

    Naranje, Kirti M; Bansal, Arun; Singhi, Sunit C

    2012-03-01

    Fainting attack or syncope in children is a common occurrence, with vasovagal syncope being the commonest cause for majority of pediatric syncope. The aim of emergency room evaluation is not to miss the rare serious underlying disorder causing syncope. A complete detailed history of the event followed by physical examination helps in categorising syncope into the three major categories-neurally mediated, cardiovascular and non cardiovascular syncope. Investigations will remain normal in majority of the cases. A 12-lead ECG and standing test should be done in all the cases which helps in establishing the cause for syncope. Management varies depending upon the cause and majority of them do not require hospital admission. PMID:21695380

  10. Infrared image object recognition based on invariant contourlet sub-band features

    NASA Astrophysics Data System (ADS)

    Mei, Xue; Xia, Liangzheng; Lin, Jinguo

    2007-11-01

    A novel feature descriptor-contourlet Fourier invariant feature, which combine contourlet decomposition and Fourier transforms and is translation-, rotation-, and scale-invariant, is put forward in this paper. Firstly, the translation and rotation invariant are achieved by Fourier transform along the circles that around the mass center of the scale-normalized target. Then statistic parameters of General Gaussian density (GGD) model of each contourlet sub-bands are evaluated. GGD parameters and contourlet decomposition coefficients are both as the features, which not only with rotation, shift and scaling invariant, but also with the contourlet inherent property of multi-resolution, local and multi-direction. We present experimental results using this descriptor in infrared image recognition, and it shows this descriptor is a good choice for object recognition.

  11. NEOWISE: Proposed Discovery of Near-Earth Objects in the Infrared by the WISE Mission.

    NASA Astrophysics Data System (ADS)

    McMillan, Robert S.; Mainzer, A. K.; Walker, R. G.; Wright, E. L.; Eisenhardt, P. R.; Cutri, R. M.; Grav, T.; WISE Science Team

    2009-01-01

    The Wide-field Infrared Survey Explorer will make hundreds of thousands of incidental detections of asteroids. Main belt asteroids as small as 3 km in diameter and hundreds of Near-Earth Objects (NEOs) as small as a few hundred meters in diameter will be above WISE's detection thresholds at 12 and 23 microns wavelength. Standard data products will include accurate positions and photometry for previously known solar system objects. NEOWISE is a proposal to identify previously unknown moving object candidates and report them promptly enough to the Minor Planet Center that they can be recovered with ground-based telescopes during their discovery apparitions. The resulting consolidation of orbital elements and measurement of visual-band apparent magnitudes will enhance knowledge of asteroid diameters and enable albedos to be determined. The sampling of the NEO population by WISE will be relatively insensitive to albedo, and therefore can be used to describe the distribution of sizes of NEOs without albedo bias. WISE's discovery tracklets of asteroids will contain 8-12 positions spanning 36 hours near the ecliptic, with better coverage at higher ecliptic latitudes. The 12 samples over 36 hours will be good for determining approximate rotation periods and IR lightcurve amplitudes. WISE will survey on great circles at 90 deg from the sun vector, coincidentally including the "sweet spots" for discovering Potentially Hazardous Asteroids. The apparent magnitudes of NEOs when detected by WISE will run to V=21 for albedos typical of NEOs. Recovery of NEOs within 10-14 days of WISE's discoveries should not require searching more than 3 square degrees. Another NEOWISE enhancement will enable access to the images and lists of extracted sources from the single-epoch WISE exposures. This will provide pre-discovery astrometry and physical data for solar system objects that are discovered after WISE's standard data processing is complete.

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

    SciTech Connect

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

    2011-05-20

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

  13. Search for faint galactic features

    SciTech Connect

    Matuska, W.; Burkhead, M.S.

    1980-01-01

    Trying to determine the size of galaxies and looking for tails and connections between galaxies can be intriguing. These very faint features are often buried in the film grain noise. Our study is of the NGC 3623, NGC 3627 and NGC 3628 region. The search for these faint features is complicated by film variation, sky background, microdensitometer drift and stars in the neighborhood of the galaxies. These questions are addressed and faint features are found with the use of judicious data stretching and averaging along suspected features.

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

    SciTech Connect

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

    2011-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Mobasher, Bahram; Crampton, David; Simard, Luc

    2010-07-01

    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.

  16. Young stellar object variability (YSOVAR): Long timescale variations in the mid-infrared

    SciTech Connect

    Rebull, L. M.; Cody, A. M.; Stauffer, J. R.; Morales-Calderón, M.; Carey, S. J. [Spitzer Science Center (SSC), Infrared Processing and Analysis Center (IPAC), 1200 East California Boulevard, California Institute of Technology, Pasadena, CA 91125 (United States); Covey, K. R. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Günther, H. M.; Poppenhaeger, K.; Wolk, S. J.; Hora, J. L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hillenbrand, L. A. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Plavchan, P. [NASA Exoplanet Science Institute (NExScI), Infrared Processing and Analysis Center (IPAC), 1200 East California Boulevard, California Institute of Technology, Pasadena, CA 91125 (United States); Gutermuth, R. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Song, I. [Physics and Astronomy Department, University of Georgia, Athens, GA 30602-2451 (United States); Barrado, D. [Departamento de Astrofísica, Centro de Astrobiología (INTA-CSIC), ESAC campus, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Bayo, A. [Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); James, D. [Cerro Tololo InterAmerican Observatory (CTIO), Casilla 603, La Serena (Chile); Vrba, F. J. [US Naval Observatory, Flagstaff Station 10391 West Naval Observatory Road, Flagstaff, AZ 86005 (United States); Alves de Oliveira, C. [European Space Agency (ESA/ESAC), P.O. Box 78, E-28691 Villanueva de la Caãda, Madrid (Spain); Bouvier, J., E-mail: rebull@ipac.caltech.edu [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble (France); and others

    2014-11-01

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

  17. High-Resolution Near-Infrared Spectroscopy of FU Orionis Objects

    NASA Astrophysics Data System (ADS)

    Hartmann, Lee; Hinkle, Kenneth; Calvet, Nuria

    2004-07-01

    We present an analysis of recent near-infrared, high-resolution spectra of the variable FU Ori objects. During a phase of rapid fading in optical brightness during 1997, V1057 Cyg exhibited shell absorption in first-overtone (v''-v'=2-0) CO lines, blueshifted by about 50 km s-1 from the system velocity. This shell component had not been seen previously, nor was it present in 1999, although some blueshifted absorption asymmetry is seen at the latter epoch. The appearance of this CO absorption shell is connected with the roughly contemporaneous appearance of blueshifted, low-excitation optical absorption lines with comparable low velocities; we suggest that this shell was also responsible for some of the peculiar emission features seen in red-optical spectra of V1057 Cyg. FU Ori continues to exhibit broad CO lines, with some evidence for the double-peaked profiles characteristic of an accretion disk; the line profiles are consistent with previous observations. Both FU Ori and V1057 Cyg continue to exhibit lower rotational broadening at 2.3 ?m than at optical wavelengths, in agreement with the prediction of differentially rotating disk models; we have a marginal detection of the same effect in V1515 Cyg. The relative population of the first-overtone CO rotational levels in the FU Ori objects suggests low excitation temperatures. We compare disk models to the observations and find agreement with overall line strengths and rotational broadening, but the observed line profiles are generally less double-peaked than predicted. We suggest that the discrepancy in line profiles is due to turbulent motions in FU Ori disks, an effect qualitatively predicted by recent simulations of the magnetorotational instability in vertically stratified accretion disks. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the NSF, on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICRT (Argentina). Based on observations obtained with the Phoenix infrared spectrograph, developed and operated by the National Optical Astronomy Observatory. The National Optical Astronomy Observatory is operated by the AURA, Inc. under cooperative agreement with the National Science Foundation.

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

    PubMed Central

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

    2011-01-01

    Background: Endometrial cancer is the most common gynaecological malignancy in the United Kingdom. Diagnosis currently involves subjective expert interpretation of highly processed tissue, primarily using microscopy. Previous work has shown that infrared (IR) spectroscopy can be used to distinguish between benign and malignant cells in a variety of tissue types. Methods: Tissue was obtained from 76 patients undergoing hysterectomy, 36 had endometrial cancer. Slivers of endometrial tissue (tumour and tumour-adjacent tissue if present) were dissected and placed in fixative solution. Before analysis, tissues were thinly sliced, washed, mounted on low-E slides and desiccated; 10 IR spectra were obtained per slice by attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy. Derived data was subjected to principal component analysis followed by linear discriminant analysis. Post-spectroscopy analyses, tissue sections were haematoxylin and eosin-stained to provide histological verification. Results: Using this approach, it is possible to distinguish benign from malignant endometrial tissue, and various subtypes of both. Cluster vector plots of benign (verified post-spectroscopy to be free of identifiable pathology) vs malignant tissue indicate the importance of the lipid and secondary protein structure (Amide I and Amide II) regions of the spectrum. Conclusion: These findings point towards the possibility of a simple objective test for endometrial cancer using ATR-FTIR spectroscopy. This would facilitate earlier diagnosis and so reduce the morbidity and mortality associated with this disease. PMID:21326237

  19. CROMOS: A cryogenic near-infrared, multi-object spectrometer for the VLT

    E-print Network

    R. Genzel; R. Hofmann; D. Tomono; N. Thatte; F. Eisenhauer; M. Lehnert; M. Tecza; R. Bender

    2001-08-20

    We discuss a cryogenic, multi-object near-infrared spectrometer as a second generation instrument for the VLT. The spectrometer combines 20 to 40 independent integral eld units (IFUs), which can be positioned by a cryogenic robot over the entire unvignetted eld of the VLT (~7'). Each IFU consists of a contiguous cluster of 20 to 30 pixels (0.15 to 0.25" per pixel). The individual IFUs have cold fore-optics and couple into the spectrograph with integrated bers-microlenses. The spectrometer has lambda/d-lambda~4000 and simultaneously covers the J-, H-, and K-bands with three HAWAII 2 detectors. The system is designed for operation both in seeing limited and MCAO modes. Its speed is approximately 3500 times greater than that of ISAAC and 60 times greater than NIRMOS (in H-band). The proposed instrument aims at a wide range of science, ranging from studies of galaxies/clusters in the high-z Universe (dynamics and star formation in z>1 galaxies, evolution of ellipticals, properties of distant, obscured far-IR and X-ray sources), to investigations of nearby starbursts, star clusters and properties of young low mass stars and brown dwarfs.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  1. Imaging performance and modeling of the Infrared Multi-Object Spectrometer focal reducer

    NASA Astrophysics Data System (ADS)

    Connelly, Joseph A.; Ohl, Raymond G., IV; Saha, Timo T.; Hadjimichael, Theo; Mentzell, John E.; Mink, Ronald G.; Hylan, Jason E.; Sparr, Leroy M.; Chambers, John; Hagopian, John J.; Greenhouse, Matthew A.; Winsor, Robert S.; MacKenty, John W.

    2003-03-01

    The Infrared Multi-Object Spectrometer (IRMOS) is a facility instrument for the Kitt Peak National Observatory 4 and 2.1 meter telescopes. IRMOS is a near-IR (0.8 2.5 ?m) spectrometer with low- to mid-resolving power (R = 300 3000). The IRMOS spectrometer produces simultaneous spectra of ~100 objects in its 2.8 x 2.0 arcmin field of view using a commercial MEMS multi-mirror array device (MMA) from Texas Instruments. The IRMOS optical design consists of two imaging subsystems. The focal reducer images the focal plane of the telescope onto the MMA field stop, and the spectrograph images the MMA onto the detector. We describe the breadboard subsystem alignment method and imaging performance of the focal reducer. This testing provides verification of the optomechanical alignment method and a measurement of near-angle scattered light due to mirror small-scale surface error. Interferometric measurements of subsystem wavefront error serve to verify alignment and are accomplished using a commercial, modified Twyman-Green laser unequal path interferometer. Image testing is then performed for the central field point. A mercury-argon pencil lamp provides the spectral line at 546.1 nm, and a CCD camera is the detector. We use the Optical Surface Analysis Code to predict the point-spread function and its effect on instrument slit transmission, and our breadboard test results validate this prediction. Our results show that scattered light from the subsystem and encircled energy is slightly worse than expected. Finally, we perform component level image testing of the MMA, and our results show that scattered light from the MMA is of the same magnitude as that of the focal reducer.

  2. a Faint and Lonely Brown Dwarf in the Solar Vicinity

    NASA Astrophysics Data System (ADS)

    1997-04-01

    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

  3. The faint galaxy contribution to the diffuse extragalactic background light

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  4. NIRSpec - Near-IR Multi-Object Spectrograph for JWST

    Microsoft Academic Search

    P. Jakobsen; S. Arribas; T. Boeker; A. Bunker; S. Charlot; D. Crampton; P. Ferruit; M. Franx; R. Maiolino; G. de Marchi; H. Moseley; B. Rauscher; M. Regan; H.-W. Rix; J. Valenti

    2005-01-01

    NIRSpec will be the first slit-based astronomical multi-object spectrograph to fly in space, and is designed to provide spectra of faint objects over the near-infrared 1.0 - 5.0 micron wavelength range at spectral resolutions of R=100, R=1000 and R=2700. The instrument's all-reflective wide-field optics, together with its novel MEMS-based programmable micro-shutter array slit selection device and its large format low-noise

  5. Near-infrared integral field spectroscopy of massive young stellar objects

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  6. YOUNG STELLAR OBJECT SEARCH TOWARD THE BOUNDARY OF THE CENTRAL MOLECULAR ZONE WITH NEAR-INFRARED POLARIMETRY

    SciTech Connect

    Yoshikawa, Tatsuhito; Nagata, Tetsuya [Department of Astronomy, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Nishiyama, Shogo; Kwon, Jungmi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Tamura, Motohide, E-mail: yosikawa@kusastro.kyoto-u.ac.jp, E-mail: nagata@kusastro.kyoto-u.ac.jp, E-mail: shogo.nishiyama@nao.ac.jp [Department of Astronomy, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan)

    2014-08-01

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

  7. High-resolution infrared molecular hydrogen images and optical images of Herbig-Haro object 43

    Microsoft Academic Search

    Richard D. Schwartz; Donald G. Jennings; Peredur M. Williams; Martin Cohen

    1988-01-01

    An infrared image of HH 43 in the 1-0 S(1) emission line of molecular hydrogen has been obtained at high spatial resolution (0arcsec.6 pixel-1). Comparison of this image with optical CCD images obtained at comparable resolution in the emission lines of Halpha and [S II] reveals a very strong spatial correlation between the infrared and optical emission. It is suggested

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    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.

  9. Wide-field infrared survey explorer observations of young stellar objects in the Lynds 1509 dark cloud in Auriga

    SciTech Connect

    Liu, Wilson M.; McCollum, Bruce; Fajardo-Acosta, Sergio [Infrared Processing and Analysis Center, California Institute of Technology, MC 100-22, Pasadena, CA 91125 (United States); Padgett, Deborah L. [National Aeronautics and Space Administration, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Terebey, Susan; Angione, John [Department of Physics and Astronomy, California State University, Los Angeles, CA 90032 (United States); Rebull, Luisa M. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Leisawitz, David, E-mail: wliu@ipac.caltech.edu [National Aeronautics and Space Administration, Goddard Space Flight Center, Code 605, Greenbelt, MD 20771 (United States)

    2014-06-01

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

  10. Near-Infrared Spectropolarimetry of Three Prototype Low-Mass Young Stellar Objects in the Taurus Dark Cloud

    Microsoft Academic Search

    Naoto Kobayashi; Tetsuya Nagata; Motohide Tamura; Taku Takeuchi; Hideki Takami; Yukiyasu Kobayashi; Shuji Sato

    1999-01-01

    We present near-infrared spectropolarimetric data between 0.9 and 4.2 mum for three prototypes of low-mass young stellar objects (YSOs), L1551 IRS 5, HL Tau, and T Tau in the Taurus dark cloud. These sources are in different classes in the standard spectral classification scheme of low-mass YSOs by Lada. The polarization curves of the observed sources show distinct differences. The

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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

  12. Detection of buried objects by fusing dual-band infrared images

    SciTech Connect

    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

    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.

  13. Objects recognition in visible and infrared images from the road scene

    Microsoft Academic Search

    A. Apatean; A. Rogozan; A. Bensrhair

    2008-01-01

    The detection of an obstacle in a traffic scene situation (obstacle which most often means a pedestrian or a vehicle) is a real challenge due to the outdoor environment and the variety of appearance of the obstacle. In this paper some details about our recognition module applied on visible and infrared image databases are presented. Given an image, or a

  14. Infrared thermography applied to the quantitative determination of spatial and thermophysical parameters of hidden included objects

    Microsoft Academic Search

    Fábio Santana Magnani; Renata Nunes Tavares da Silva

    2007-01-01

    In this paper we present a study of case of determination of material properties using information from the surface temperature distribution obtained by infrared thermography. Two samples are used for the study: one in gypsum plaster and another with a hidden included steel cylinder. Both samples are heated to 120°C and their surface temperature distributions are recorded while they are

  15. Detection of buried objects by fusing dual-band infrared images

    Microsoft Academic Search

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

    1993-01-01

    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

  16. Diffraction-limited CCD imaging with faint reference stars

    E-print Network

    R. N. Tubbs; J. E. Baldwin; C. D. Mackay; G. C. Cox

    2002-03-26

    By selecting short exposure images taken using a CCD with negligible readout noise we obtained essentially diffraction-limited 810 nm images of faint objects using nearby reference stars brighter than I=16 at a 2.56 m telescope. The FWHM of the isoplanatic patch for the technique is found to be 50 arcseconds, providing ~20% sky coverage around suitable reference stars.

  17. Simultaneous X-ray, radio, near-infrared, and optical monitoring of Young Stellar Objects in the Coronet cluster

    E-print Network

    Forbrich, J; Menten, K M; Neuhäuser, R; Walter, F M; Tamura, M; Matsunaga, N; Kusakabe, N; Nakajima, Y; Brandeker, A; Fornasier, S; Posselt, B; Tachihara, K; Broeg, C; Preibisch, T

    2007-01-01

    Multi-wavelength (X-ray to radio) monitoring of Young Stellar Objects (YSOs) can provide important information about physical processes at the stellar surface, in the stellar corona, and/or in the inner circumstellar disk regions. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. Several multi-wavelength studies have been successfully performed for field stars and approx. 1-10 Myr old T Tauri stars, but so far no such study succeeded in detecting simultaneous X-ray to radio variability in extremely young objects like class I and class 0 protostars. Here we present the first simultaneous X-ray, radio, near-infrared, and optical monitoring of YSOs, targeting the Coronet cluster in the Corona Australis star-forming region, which harbors at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. [...] Seven objects are detec...

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

    Microsoft Academic Search

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

    2002-01-01

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

  19. A Search for Optically Faint GEO Debris

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  20. 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.

  1. The faint young Sun problem

    NASA Astrophysics Data System (ADS)

    Feulner, Georg

    2012-05-01

    For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the “faint young Sun problem.” For the early Earth, models of stellar evolution predict a solar energy input to the climate system that is about 25% lower than today. This would result in a completely frozen world over the first 2 billion years in the history of our planet if all other parameters controlling Earth's climate had been the same. Yet there is ample evidence for the presence of liquid surface water and even life in the Archean (3.8 to 2.5 billion years before present), so some effect (or effects) must have been compensating for the faint young Sun. A wide range of possible solutions have been suggested and explored during the last four decades, with most studies focusing on higher concentrations of atmospheric greenhouse gases like carbon dioxide, methane, or ammonia. All of these solutions present considerable difficulties, however, so the faint young Sun problem cannot be regarded as solved. Here I review research on the subject, including the latest suggestions for solutions of the faint young Sun problem and recent geochemical constraints on the composition of Earth's early atmosphere. Furthermore, I will outline the most promising directions for future research. In particular I would argue that both improved geochemical constraints on the state of the Archean climate system and numerical experiments with state-of-the-art climate models are required to finally assess what kept the oceans on the Archean Earth from freezing over completely.

  2. Searching for Optically Faint GEO Debris

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

  3. Nirspec, The Near-ir Multi-object Spectrograph For Jwst

    Microsoft Academic Search

    Peter Jakobsen; S. Arribas; T. Beck; S. Birkmann; T. Boeker; A. Bunker; S. Charlot; G. De Marchi; P. Ferruit; M. Franx; R. Maiolino; H. Moseley; J. Muzerolle; B. Rauscher; M. Regan; H. Rix; M. Sirianni; D. Soderblom; J. Tumlinson; J. Valenti; C. Willott

    2011-01-01

    NIRSpec will be the first slit-based astronomical multi-object spectrograph to fly in space, and is designed to provide spectra of faint objects over the near-infrared 1.0 - 5.0 micron wavelength range at spectral resolutions of R=100, R=1000 and R=2700. The instrument's all-reflective wide-field optics, together with its novel MEMS-based programmable micro-shutter array slit selection device and its large format low-noise

  4. NIRSpec, the Near-IR Multi-object Spectrograph for JWST

    Microsoft Academic Search

    Peter Jakobsen; S. Arribas; T. Beck; T. Boeker; A. Bunker; S. Carpano; S. Charlot; G. De Marchi; P. Ferruit; M. Franx; R. Maiolino; H. Moseley; B. Rauscher; M. Regan; H. W. Rix; J. Valenti; C. Willott

    2009-01-01

    NIRSpec will be the first slit-based astronomical multi-object spectrograph to fly in space, and is designed to provide spectra of faint objects over the near-infrared 1.0 - 5.0 micron wavelength range at spectral resolutions of R=100, R=1000 and R=2700. The instrument's all-reflective wide-field optics, together with its novel MEMS-based programmable micro-shutter array slit selection device and its large format low-noise

  5. NIRSpec, the Near-IR Multi-object Spectrograph for JWST

    Microsoft Academic Search

    Peter Jakobsen; S. Arribas; T. Beck; S. Birkmann; T. Boeker; A. Bunker; S. Charlot; G. De Marchi; P. Ferruit; M. Franx; R. Maiolino; H. Moseley; J. Muzerolle; B. Rauscher; M. Regan; H. W. Rix; M. Sirianni; J. Tumlinson; J. Valenti; C. Willott

    2010-01-01

    NIRSpec will be the first slit-based astronomical multi-object spectrograph to fly in space, and is designed to provide spectra of faint objects over the near-infrared 1.0 - 5.0 micron wavelength range at spectral resolutions of R=100, R=1000 and R=2700. The instrument's all-reflective wide-field optics, together with its novel MEMS-based programmable micro-shutter array slit selection device and its large format low-noise

  6. Faintness

    MedlinePLUS

    ... should not be used as a substitute for evaluation and treatment by a physician. Please review our terms of use . Home Symptom Checkup Injury Checkup Disease Checkup Women's Checkup Pregnancy Checkup Baby Checkup Mens Checkup Stephen J. Schueler, M.D. About Stephen ...

  7. 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 ...

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  9. Near-infrared emission-line images of three Herbig-Haro objects

    SciTech Connect

    Stapelfeldt, K.R.; Scoville, N.Z.; Beichman, C.A.; Hester, J. J.; Gautier, T.N., III (Palomar Observatory, Pasadena, CA (USA))

    1991-04-01

    Flux-calibrated imagery in five emission-line and four narrow-band continuum filters are presented for three classical Herbig-Haro (HH) objects, HH 7-11, HH 12, and HH 34. 1.64 micron forbidden Fe II emission is detected in all three objects whose intensity is typically 20 percent. This line should be an excellent tracer of shocked ionized gas in highly obscured regions. Extinction appears to be unimportant in determining the morphology of these HH object systems. No near-IR continuum emission was detected from any of the HH objects, implying that these regions do not contain embedded stars. At positions where the flow terminates against a large obstacle, there are significant offsets between the shocked flow material and the shocked ambient medium. 39 refs.

  10. Near-infrared emission-line images of three Herbig-Haro objects

    NASA Technical Reports Server (NTRS)

    Stapelfeldt, Karl R.; Scoville, Nicholas Z.; Beichman, Charles A.; Hester, J. Jeff; Gautier, Thomas N., III

    1991-01-01

    Flux-calibrated imagery in five emission-line and four narrow-band continuum filters are presented for three classical Herbig-Haro (HH) objects, HH 7-11, HH 12, and HH 34. 1.64 micron forbidden Fe II emission is detected in all three objects whose intensity is typically 20 percent. This line should be an excellent tracer of shocked ionized gas in highly obscured regions. Extinction appears to be unimportant in determining the morphology of these HH object systems. No near-IR continuum emission was detected from any of the HH objects, implying that these regions do not contain embedded stars. At positions where the flow terminates against a large obstacle, there are significant offsets between the shocked flow material and the shocked ambient medium.

  11. The IRAS faint source survey

    NASA Technical Reports Server (NTRS)

    Moshir, Mehrdad

    1991-01-01

    The principal features of the IRAS Faint Source Survey (FSS), a new product resulting from the extended IRAS mission, are reviewed. The FSS has achieved an increase in sensitivity of about a factor of 2.5 relative to the IRAS Point Source Catalog by coadding the data before extracting sources. The FSS was produced by point-source filtering the individual detector data streams and then coadding the data streams using a trimmed-average algorithm. The discussion covers FSS production methods; reliability, completeness, and positional accuracy of the FSS; and FSS view of the IR sky.

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

    NASA Technical Reports Server (NTRS)

    Tholen, David J.

    1991-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2009-01-01

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

  14. Spectral Indices of Faint Radio Sources

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  15. Infrared and Radio Observations of a Small Group of Protostellar Objects in the Molecular Core, L1251-C

    NASA Astrophysics Data System (ADS)

    Kim, Jungha; Lee, Jeong-Eun; Choi, Minho; Bourke, Tyler L.; Evans, Neal J., II; Di Francesco, James; Cieza, Lucas A.; Dunham, Michael M.; Kang, Miju

    2015-05-01

    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 in the east–west direction with its intensity peak at the center of L1251A has been detected at 350 and 850 ?m with the Caltech Submillimeter Observatory and James Clerk Maxwell telescopes, tracing dense envelope material around L1251A. The single-dish data from the Korean VLBI Network and TRAO telescopes show inconsistencies between the intensity peaks of several molecular emission lines and that of the continuum emission, suggesting complex distributions of molecular abundances around L1251A. The Submillimeter Array 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 the Infrared Array Camera image and the weakest source in the 1.3 mm dust-continuum map. IRS 1 is the strongest candidate for the driving source of the newly detected compact CO 2–1 outflow. Over the entire region (14? × 14?) of L125l-C, 3 Class I and 16 Class II sources have been detected, including three young stellar objects (YSOs) in L1251A. A comparison between the average projected distance among the 19 YSOs in L1251-C and that among the 3 YSOs in L1251A suggests that L1251-C is an example of low-mass cluster formation where protostellar objects form in a small group.

  16. Near Infrared Observations Of TNOs With SINFONI

    NASA Astrophysics Data System (ADS)

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

    2007-10-01

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

  17. The ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Smith, Harding E.

    1999-01-01

    As part of the ISO-IRAS Faint Galaxy Survey ISO Satellite observations of over 600 IRAS sources have been obtained with the ISOCAM instrument. Because our survey strategy involved relatively short integrations, great care was required in developing analysis software including cosmic-ray and transient removal and calibration. These observations have now been through final pipeline processing at IPAC and ground-based follow-up is ongoing. The observations are for sources from two samples: a " Filler' sample selected to be at z greater than 0.1 and a fainter sample which selected for the highest redshift galaxies in the IRAS survey, with redshifts 0.2 less than z less than 1.0. I now have obtained ground-based follow-up spectrophotometry at Lick and Palomar observatories for 100 LFIRGs with 0.1 less than z less than 0.7. Our observations have confirmed that these systems are comparable to nearby LFIRGs such as Arp 220, with L (sub -)(fir) greater than 10(exp 11) L(sub -) sun and typically HII/Liner optical excitation. About 10% of the galaxies show true AGN (Sy2) excitation. Based on our work on a nearby complete sample of LFIRGS, we believe that the majority of these systems are luminous Starbursts, thus this project is tracing the luminous end of the galaxy star-forming luminosity function - the (infrared) star-formation history of the Universe to z approx. 1, a topic of some considerable recent interest. A by-product of these ISOCAM observations is approximately 1 square degree of deep 2 microns pointings outside the IRAS error boxes, allowing us an independent estimate of the mid-infrared log N - log S relation. Ground-based observations of this sample are continuing.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

  19. Investigation of small solar system objects with the space telescope

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1979-01-01

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

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

    E-print Network

    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

    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...

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

    NASA Astrophysics Data System (ADS)

    Qi, Baojun; Wu, Tao; He, Hangen

    2012-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

  3. The faint end of the galaxy luminosity function

    NASA Technical Reports Server (NTRS)

    Treyer, Marie A.; Silk, Joseph

    1994-01-01

    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.

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

    Microsoft Academic Search

    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

    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

  5. LUCIFER-MOS: a cryogenic multi-object infrared spectrograph for the LBT

    NASA Astrophysics Data System (ADS)

    Hofmann, Reiner; Thatte, Niranjan A.; Tecza, Matthias; Eisenhauer, Frank; Lehnert, Matthew

    2000-08-01

    LUCIFER-MOS is a liquid nitrogen cooled near IR multi object spectrograph imaging 20 freely selectable sub-fields of about 2.2 inch by 1.8 inch and 6 by 4 image elements each on the entrance slit of the LUCIFER spectrograph. The image elements are re-arranged by 480 fused silica fibers of 50 micrometers core diameter and 100 micrometers total diameter with integrated, hexagonal lenslets of 0.6 mm width corresponding to a 0.3 inch field. The pre-optics magnifies the telescope image by a factor 3.3, thus adapting the telescope plate scale to the lenslet scale, and additionally providing a cold stop. The post-optics converts the f/3 fiber output beam to the f/15 beam accepted by the spectrograph. Each of the 20 6 by 4 fiber arrays together with its pre-optics is mounted in a spider arm which can be freely positioned within the 200 mm diameter field of view by a cryogenic robot. The robot performs three rotational movements to position the spider arms and is driven by cold stepper motors. The spider arms are locked in their positions by two permanent magnets each. Their magnetic field can be compensated by coils to unlock the arms and move them across the field of view.

  6. OH-selected AGB and Post-AGB Objects. I. Infrared and Maser Properties

    NASA Astrophysics Data System (ADS)

    Sevenster, Maartje N.

    2002-05-01

    Using 766 compact objects found in a systematic survey of the Galactic plane in the 1612 MHz masing OH line, new light is cast on the IR properties of evolved stars on the thermally pulsing asymptotic giant branch (AGB) and beyond. The usual mid-IR selection criteria for post-AGB, based on IRAS colors, largely fail to distinguish early post-AGB stages. A two-color diagram from much narrower band MSX flux densities, with bimodal distributions, provides a better tool for doing this. Four mutually consistent selection criteria for OH-masing red proto-planetary nebulae are given, as well as two for early post-AGB masers and one for all post-AGB masers including the earliest ones. All these criteria miss a group of blue, high-outflow post-AGB sources with 60 ?m excess; these will be discussed in detail in Paper II. The majority of post-AGB sources show regular double-peaked spectra in the OH 1612 MHz line, with fairly low outflow velocities, although the fractions of single peaks and irregular spectra may vary with age and mass. The OH flux density shows a fairly regular relation with the stellar flux and the envelope optical depth, with the maser efficiency increasing with IRAS color R21. The OH flux density is linearly correlated with the 60 ?m flux density.

  7. Hubble Deep Fever: A faint galaxy diagnosis

    E-print Network

    S. P. Driver

    1998-02-26

    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 !

  8. Hubble Deep Fever A faint galaxy diagnosis

    E-print Network

    Driver, S P

    1998-01-01

    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 !

  9. Adaptive Optics Imaging of Faint Companions: Current & Future Prospects

    NASA Astrophysics Data System (ADS)

    Close, Laird M.

    I briefly describe how diffraction-limited imaging with adaptive optics (AO) can detect low mass companions (young massive brown dwarfs for example). I review how current curvature AO systems can already detect point sources 1 million times fainter at separations of 3 arcsec in median seeing (0.65 arcsec). I show real examples of very faint companion detections made with the University of Hawaii AO system located at CFHT on Mauna Kea around the young (2 Myr) nearby (132 pc) Herbig Ae/Be star MWC480. Moreover, I show that the four faint (H=18--19 mag) companions within 6 arcsec of MWC480 (H=7.0 mag) are unlikely to be physical since they are non-common proper motion objects. I point out that the current 8--10m class AO systems will detect even fainter companions at closer separations with 0.03--0.06 arcsec NIR imaging.

  10. Configurable slit-mask unit of the multi-object spectrometer for infra-red exploration for the Keck telescope: integration and tests

    Microsoft Academic Search

    Peter Spanoudakis; Laurent Giriens; Simon Henein; Leszek Lisowski; Aidan O'Hare; Emmanuel Onillon; Philippe Schwab; Patrick Theurillat

    2008-01-01

    A Configurable Slit Unit (CSU) has been developed for the Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) instrument to be installed on the Keck 1 Telescope on Mauna Kea, Hawaii. MOSFIRE will provide NIR multi-object spectroscopy over a field of view of 6.1' x 6.1'. The reconfigurable mask allows the formation of 46 optical slits in a 267 x 267 mm2

  11. The LUCIFER MOS: a full cryogenic mask handling unit for a near-infrared multi-object spectrograph

    NASA Astrophysics Data System (ADS)

    Buschkamp, Peter; Hofmann, Reiner; Gemperlein, Hans; Polsterer, Kai; Ageorges, Nancy; Eisenhauer, Frank; Lederer, Reinhard; Honsberg, Mathias; Haug, Marcus; Eibl, Johann; Seifert, Walter; Genzel, Reinhard

    2010-07-01

    The LUCIFER-MOS unit is the full cryogenic mask-exchange unit for the near-infrared multi-object spectrograph LUCIFER at the Large Binocular Telescope. We present the design and functionality of this unique device. In LUCIFER the masks are stored, handled, and placed in the focal plane under cryogenic conditions at all times, resulting in very low thermal background emission from the masks during observations. All mask manipulations are done by a novel cryogenic mask handling robot that can individually address up to 33 fixed and user-provided masks and place them in the focal plane with high accuracy. A complete mask exchange cycle is done in less than five minutes and can be run in every instrument position and state reducing instrument setup time during science observations to a minimum. Exchange of old and new MOS masks is likewise done under cryogenic conditions using a unique exchange drive mechanism and two auxiliary cryostats that attach to the main instrument cryostat.

  12. Hubble Space Telescope/Near-Infrared Camera and Multi-Object Spectrometer Observations of the GLIMPSE9 Stellar Cluster

    NASA Astrophysics Data System (ADS)

    Messineo, Maria; Figer, Donald F.; Davies, Ben; Kudritzki, R. P.; Rich, R. Michael; MacKenty, John; Trombley, Christine

    2010-01-01

    We present Hubble Space Telescope/Near-Infrared Camera and Multi-Object Spectrometer photometry, and low-resolution K-band spectra of the GLIMPSE9 stellar cluster. The newly obtained color-magnitude diagram shows a cluster sequence with H - KS = ~1 mag, indicating an interstellar extinction A _K_s = 1.6 ± 0.2 mag. The spectra of the three brightest stars show deep CO band heads, which indicate red supergiants with spectral type M1-M2. Two 09-B2 supergiants are also identified, which yield a spectrophotometric distance of 4.2 ± 0.4 kpc. Presuming that the population is coeval, we derive an age between 15 and 27 Myr, and a total cluster mass of 1600 ± 400 M sun, integrated down to 1 M sun. In the vicinity of GLIMPSE9 are several H II regions and supernova remnants, all of which (including GLIMPSE9) are probably associated with a giant molecular cloud (GMC) in the inner galaxy. GLIMPSE9 probably represents one episode of massive star formation in this GMC. We have identified several other candidate stellar clusters of the same complex.

  13. Food for the photometrists - Faint galaxies revealed

    NASA Astrophysics Data System (ADS)

    Malin, D. F.

    The advantages of photographic plates over CCD detectors for some types of astronomical photometry (uniformity over large areas and information-storage capacity) are discussed, and illustrated using images of faint galaxies and faint galactic structures. It is pointed out that the photographic amplification technique (Malin, 1978), although at present only qualitative, is much more time-efficient than digital scanning. Consideration is also given to the production of full-color images by superimposition of B, V, and R plates.

  14. Massive Galaxies and Extremely Red Objects at z = 1-3 in Cosmological Hydrodynamic Simulations: Near-Infrared Properties

    NASA Astrophysics Data System (ADS)

    Nagamine, Kentaro; Cen, Renyue; Hernquist, Lars; Ostriker, Jeremiah P.; Springel, Volker

    2005-07-01

    Recent observations have revealed a population of red massive galaxies at high redshift that are challenging to explain in terms of hierarchical galaxy formation models. We analyze this ``massive galaxy problem'' with two different types of hydrodynamic simulations-Eulerian total variation diminishing (TVD) and smoothed particle hydrodynamics (SPH)-of a concordance ? cold dark matter (?CDM) universe. We consider two separate but connected aspects of the problem posed by these extremely red objects (EROs): (1) the mass scale of these galaxies and (2) their red colors. We perform spectrophotometric analyses of simulated galaxies in B,z,R,I,Js,Ks,andK filters and compare their near-infrared (near-IR) properties with observations at redshift z=1-3. We find that the simulated galaxies brighter than the magnitude limit of KVega=20 mag have stellar masses M*>~1011h-1Msolar and a number density of a few times 10-4h3Mpc-3 at z~2, in good agreement with the observed number density in the K20 survey. Therefore, our hydrodynamic simulations do not exhibit the mass-scale problem. The answer to the ``redness problem'' is less clear because of our poor knowledge of the amount of dust extinction in EROs and the uncertain fraction of star-forming EROs. However, our simulations can account for the observed comoving number density of ~1×10-4 Mpc-3 at z=1-2 if we assume a uniform extinction of E(B-V)=0.4 for the entire population of simulated galaxies. Upcoming observations of the thermal emission of dust in 24 ?m by the Spitzer Space Telescope will help to better estimate the dust content of EROs at z=1-3 and thus to further constrain the star formation history of the universe and theoretical models of galaxy formation.

  15. Particle-based ablation model for faint meteors

    NASA Astrophysics Data System (ADS)

    Stokan, E.; Campbell-Brown, M.

    2014-07-01

    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.

  16. An X-ray and infrared survey of the Lynds 1228 cloud core

    SciTech Connect

    Skinner, Stephen L. [CASA, University of Colorado, Boulder, CO 80309-0389 (United States); Rebull, Luisa [Spitzer Science Center/Caltech, M/S 220-6, 1200 East California Blvd., Pasadena, CA 91125 (United States); Güdel, Manuel, E-mail: stephen.skinner@colorado.edu, E-mail: rebull@ipac.caltech.edu, E-mail: manuel.guedel@univie.ac.at [Department of Astrophysics, University of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria)

    2014-04-01

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

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

    SciTech Connect

    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

    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.

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

    E-print Network

    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

    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.

  19. Dust properties of the faint GRB 080603A .

    NASA Astrophysics Data System (ADS)

    Guidorzi, C.

    GRB 080603A was an optically faint burst occurred at z=1.687, whose optical afterglow peaked with R˜18 mag at 26 minutes from the burst onset. The dust extinction toward GRB 080603A within the host galaxy is high, AV,z=0.8 mag, and the well-sampled X-ray-to-near-infrared spectral energy distribution is interesting in requiring an LMC2 extinction profile, in contrast to the majority of GRBs, with possible evidence for the presence of the 2175 Å bump. From the late-time multi-filter photometry obtained with the Keck/LRIS, the host galaxy is typical of long GRBs. Its SED is best fit with that of a starburst galaxy with an age of 130 Myr, M_B=-20.7, and a similar dust extinction to that along the GRB sightline. GRB 080603A bridges the gap between the optically missed (either because heavily dust-obscured or because intrinsically faint) and optically bright GRBs. As such, it highlights the importance of prompt and deep (Rgtrsim 20 mag) follow-up observations.

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

    NASA Technical Reports Server (NTRS)

    Morris, Elena; Flint, Graham

    1991-01-01

    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.

  1. Color distribution of faint galaxies and quasi-stellar objects

    Microsoft Academic Search

    R. G. Kron

    1983-01-01

    The results of recent automated multicolor surveys of the flux emitted by galaxies are reviewed. A 4-m survey of 12 fields in the J+ and F bands has revealed a trend to the blue at B = 21; the blue shift may be enhanced at B-values from 22-24. Complete samples taken by Koo (1981) in the U, J, F, and

  2. LBT/LUCIFER near-infrared spectroscopy of PV Cephei. An outbursting young stellar object with an asymmetric jet

    NASA Astrophysics Data System (ADS)

    Caratti o Garatti, A.; Garcia Lopez, R.; Weigelt, G.; Tambovtseva, L. V.; Grinin, V. P.; Wheelwright, H.; Ilee, J. D.

    2013-06-01

    Context. Young stellar objects (YSOs) occasionally experience enhanced accretion events, the nature of which is still poorly understood. The discovery of various embedded outbursting YSOs has recently questioned the classical definition of EXors and FUors. Aims: We present a detailed spectroscopic investigation of the young eruptive star PV Cep, to improve our understanding of its nature and characterise its circumstellar environment after its last outburst in 2004. Methods: The analysis of our medium-resolution spectroscopy in the near-infrared (NIR, 0.9-2.35 ?m), collected in 2012 at the Large Binocular Telescope with the IR spectrograph LUCIFER, allows us to infer the main stellar parameters (visual extinction, accretion luminosity, mass accretion and ejection rates), and model the inner disc, jet, and wind. Results: The NIR spectrum displays several strong emission lines associated with accretion/ejection activity and circumstellar environment. Our analysis shows that the brightness of PV Cep is fading, as well as the mass accretion rate (2 × 10-7 M? yr-1 in 2012 vs. ~5 × 10-6 M? yr-1 in 2004), which is more than one order of magnitude lower than in the outburst phase. Among the several emission lines, only the [Fe ii] intensity increased after the outburst. The observed [Fe ii] emission delineates blue- and red-shifted lobes, both with high- and low-velocity components, which trace an asymmetric jet and wind, respectively. The observed emission in the jet has a dynamical age of 7-8 years, indicating that it was produced during the last outburst. The visual extinction decreases moving from the red-shifted (AV(red) = 10.1 ± 0.7 mag) to the blue-shifted lobe (AV(blue) = 6.5 ± 0.4 mag). We measure an average electron temperature of 17 500 K and electron densities of 30 000 cm-3 and 15 000 cm-3 for the blue and the red lobe, respectively. The mass ejection rate in both lobes is ~1.5 × 10-7 M? yr-1, approximately matching the high accretion rate observed during and immediately after the outburst (?out/?acc ~ 0.05-0.1). The observed jet/outflow asymmetries are consistent with an inhomogeneous medium. Our modelling of the CO emission hints at a small-scale gaseous disc ring, extending from ~0.2-0.4 AU to ~3 AU from the source, with an inner temperature of ~3000 K. Our H i lines modelling indicates that most of the observed emission comes from an expanding disc wind at Te = 10 000 K. The line profiles are strongly affected by scattering, disc screening, and outflow self-absorption. Conclusions: According to the classical definition, PV Cep is not an EXor object, because it is more massive and younger than typical EXors. Nevertheless, its spectrum shows the signature of an "EXor-like" outburst, suggesting a common origin. Based on observations collected at LBT. The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota and University of Virginia.Appendix A is available in electronic form at http://www.aanda.org

  3. On the extendedness of faint ultraviolet excess quasar candidates

    NASA Astrophysics Data System (ADS)

    Edwards, G.; Borra, E. F.; Hardy, E.

    1985-02-01

    A search for UV excess quasars based on deep U, J, and F plates taken with the Canada-France-Hawaii telescope has been conducted. The plates were fully digitized and analyzed with automated software. After applying a technique for separating stars from galaxies, the surprising result was obtained that a significant fraction of the quasar candidates are not starlike. The extendedness of most (but not all) of these objects is not detectable by ordinary eye inspection. The possible nature of these objects is briefly discussed, concluding that a simple explanation is that they are compact blue galaxies. In this case, quasar counts based uniquely on the ultraviolet excess criterion have overestimated the surface density of faint quasars (B greater than 21) by more than a factor of 2. The possibility that these objects may be quasar remnants is also raised

  4. Infrared Gallery

    NSDL National Science Digital Library

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

  5. Faint detection of exoplanets in microlensing surveys

    SciTech Connect

    Brown, Robert A., E-mail: rbrown@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-06-20

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

  6. The Faint End of the HI Mass Function

    E-print Network

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

    2005-08-02

    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.

  7. The Evolution in the Faint-End Slope of the Quasar Luminosity Function

    E-print Network

    Philip F. Hopkins; Lars Hernquist; Thomas J. Cox; Tiziana Di Matteo; Brant Robertson; Volker Springel

    2005-08-30

    (Abridged) Based on numerical simulations of galaxy mergers that incorporate black hole (BH) growth, we predict the faint end slope of the quasar luminosity function (QLF) and its evolution with redshift. Our simulations have yielded a new model for quasar lifetimes where the lifetime depends on both the instantaneous and peak quasar luminosities. This motivates a new interpretation of the QLF in which the bright end consists of quasars radiating at nearly their peak luminosities, but the faint end is mostly made up of quasars in less luminous phases of evolution. The faint-end QLF slope is then determined by the faint-end slope of the quasar lifetime for quasars with peak luminosities near the observed break. We determine this slope from the quasar lifetime as a function of peak luminosity, based on a large set of simulations spanning a wide variety of host galaxy, merger, BH, and ISM gas properties. Brighter peak luminosity (higher BH mass) systems undergo more violent evolution, and expel and heat gas more rapidly in the final stages of quasar evolution, resulting in a flatter faint-end slope (as these objects fall below the observed break in the QLF more rapidly). Therefore, as the QLF break luminosity moves to higher luminosities with increasing redshift, implying a larger typical quasar peak luminosity, the faint-end QLF slope flattens. From the quasar lifetime as a function of peak luminosity and this interpretation of the QLF, we predict the faint-end QLF slope and its evolution with redshift in good agreement with observations. Although BHs grow anti-hierarchically (with lower-mass BHs formed primarily at lower redshifts), the observed change in slope and differential or luminosity dependent density evolution in the QLF is completely determined by the luminosity-dependent quasar lifetime and physics of quasar feedback.

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

    NASA Astrophysics Data System (ADS)

    Gomez Gonzalez, Laura

    2012-01-01

    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.

  9. The population of tiny near-Earth objects observed by NEOWISE

    SciTech Connect

    Mainzer, A.; Bauer, J.; Masiero, J.; Nugent, C. R.; Stevenson, R.; Clyne, E.; Cukrov, G. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ 85719 (United States); Cutri, R. M.; Masci, F. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Wright, E., E-mail: amainzer@jpl.nasa.gov [Department of Physics and Astronomy, UCLA, P.O. Box 91547, Los Angeles, CA 90095-1547 (United States)

    2014-04-01

    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 105 close approaching near-Earth objects (NEOs) by the Wide-field Infrared Survey Explorer (WISE) 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.

  10. The FIRST Sample of Ultraluminous Infrared Galaxies at High Redshift. I. Sample and Near-Infrared Morphologies

    NASA Astrophysics Data System (ADS)

    Stanford, S. A.; Stern, Daniel; van Breugel, Wil; De Breuck, Carlos

    2000-11-01

    We present a new sample of distant ultraluminous infrared galaxies. The sample was selected from a positional cross-correlation of the IRAS Faint Source Catalog with the FIRST database. Objects from this set were selected for spectroscopy by virtue of following the well-known star-forming galaxy correlation between 1.4 GHz and 60 ?m flux, and by being optically faint on the POSS. Optical identification and spectroscopy were obtained for 108 targets at the Lick Observatory 3 m telescope. Most objects show spectra typical of starburst galaxies and do not show the high-ionization lines of active galactic nuclei. The redshift distribution covers 0.1objects at z>0.5 and an average redshift of z=0.31. K-band images were obtained at the IRTF, Lick, and Keck observatories in sub-arcsec seeing of all optically identified targets. About two-thirds of the objects appear to be interacting galaxies, while the other one-third appear to be normal. Nearly all the identified objects have far-IR luminosities greater than 1011 Lsolar, and ~25% have LFIR>1012 Lsolar.

  11. Complex Organic Matter in Space: About the Chemical Composition of Carriers of the Unidentified Infrared Bands (UIBs) and Protoplanetary Emission Spectra Recorded from Certain Astrophysical Objects

    NASA Astrophysics Data System (ADS)

    Cataldo, Franco; Keheyan, Yeghis; Heymann, Dieter

    2004-02-01

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

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

    PubMed

    Cataldo, Franco; Keheyan, Yeghis; Heymann, Dieter

    2004-02-01

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

  13. Constraining the luminosity function of faint undetected i-dropout galaxies

    NASA Astrophysics Data System (ADS)

    Calvi, V.; Pizzella, A.; Stiavelli, M.; Morelli, L.; Corsini, E. M.; Dalla Bontà, E.; Bradley, L.; Koekemoer, A. M.

    2013-07-01

    We present a new technique to quantify the light contribution coming from the faint high-redshift (z ˜ 6) galaxies below the detection threshold of imaging data, set conventionally at S/N = 4.5. We illustrate the technique with an application to Hubble Space Telescope Advanced Camera for Surveys images in the F775W and F850LP filters of the Ultra Deep Field parallel field NICP12. The aim of this analysis is to extend by a few magnitudes the faint end of the luminosity function at z ˜ 6. After masking all the detected sources in the field, we apply a fast Fourier transform to obtain the spatial power spectrum of the background signal. The power spectrum permits us to separate the background noise signal, the residuals due to the data reduction of the wide field and the overall signal produced by faint galaxies. The ratio of the signal in the i775 and z850 bands is used to estimate the contribution of the faint i-dropout objects. We rely on extensive Monte Carlo simulations to characterize various sources of uncertainty and quantify the number of faint i-dropout galaxies in the field. The analysis allows us to put constraints on the luminosity function at z ˜ 6 down to z850 = 30 mag, 2.5 mag fainter than with standard techniques on the same data. The data are consistent with a faint-end slope of the luminosity function of ? = -1.9. Assuming a specific set of values for the clumping factor, escape fraction and spectral energy distribution, we find that the z ˜ 6 undetected galaxies down to z850 = 30 mag could have driven cosmic reionization.

  14. Star Formation Rates in Faint Radio Galaxies

    E-print Network

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

    1998-05-27

    The decimetric radio continuum luminosity of a star-forming galaxy appears to be directly proportional to the rate of formation of supernovae in the galaxy. Since decimetric radiation does not suffer significant extinction and is not directive, radio luminosities may thus provide a particularly straightforward way to determine the current rate of star formation. Using a sample of over 700 local galaxies we confirm the utility of the radio luminosity as a measure of star formation rate by showing concordance with the rates predicted by U-band, H-alpha, and far-infrared luminosites. We also show that there are systematic discrepancies between these various indicators, suggesting that the H-alpha luminosity may underestimate the star formation rate by approximately an order of magnitude when the star formation rate is more than 20 solar mass per year. We use this calibration and the measured radio luminosities of sub-mJy radio sources to infer the star formation rate in approximately 60 star-forming galaxies at moderate (z = 0.1) redshifts, both as the actual rate and as the fraction of the existing mass of stars in the galaxy. For some of these objects the inferred current rate of star formation could increase the stellar mass in the galaxy by approximately 10% over an interval of about 30 Myr.

  15. A Survey of Faint Galaxy Pairs

    E-print Network

    Carlberg; Pritchet; Infante

    1994-01-31

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

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  17. High-Resolution Mid-Infrared Spectroscopy of NGC 7538 IRS 1: Probing Chemistry in a Massive Young Stellar Object

    NASA Astrophysics Data System (ADS)

    Knez, Claudia; Lacy, John H.; Evans, Neal J., II; van Dishoeck, Ewine F.; Richter, Matthew J.

    2009-05-01

    We present high-resolution (R = 75,000-100,000) mid-infrared spectra of the high-mass embedded young star IRS 1 in the NGC 7538 star-forming region. Absorption lines from many rotational states of C2H2, 13C12CH2, CH3, CH4, NH3, HCN, HNCO, and CS are seen. The gas temperature, column density, covering factor, line width, and Doppler shift for each molecule are derived. All molecules were fit with two velocity components between -54 and -63 km s-1. We find high column densities (~1016 cm-2) for all the observed molecules compared to values previously reported and present new results for CH3 and HNCO. Several physical and chemical models are considered. The favored model involves a nearly edge-on disk around a massive star. Radiation from dust in the inner disk passes through the disk atmosphere, where large molecular column densities can produce the observed absorption line spectrum.

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

    SciTech Connect

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

    2009-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  20. Exploring the faint source population at 15.7 GHz

    NASA Astrophysics Data System (ADS)

    Whittam, Imogen

    2014-10-01

    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

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

    NASA Technical Reports Server (NTRS)

    Sanders, David B.

    1997-01-01

    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.

  2. Optical Color Selection of Faint AGN in the COSMOS Field

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  3. Observing Faint Companions Close to Bright Stars

    NASA Astrophysics Data System (ADS)

    Serabyn, Eugene

    2012-04-01

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

  4. First Results from the ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Wolstencroft, R. D.; Wehrle, A. E.; Levine, D. A.

    1997-01-01

    We present the first result 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 12um ISOCAM AND 90um ISOPHOT observation.

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

    E-print Network

    Henning, Thomas

    arXiv:1204.3473v1[astro-ph.SR]16Apr2012 Mid-Infrared Spectral Variability Atlas of Young Stellar that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying 1 Leiden a mid-infrared spectral atlas containing observations of 68 low- and intermediate mass young stellar

  6. Star formation in infrared bright and infrared faint starburst interacting galaxies

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

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

    SciTech Connect

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

    2012-09-20

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

  9. Hot Young Solution to Faint Sun Paradox

    NASA Astrophysics Data System (ADS)

    Riofrio, L.

    2006-12-01

    The "Faint Young Sun" has been a paradox of astrophysics. The standard solar model predicts that 4 billion years ago Earth was too cold to support life. Geology and the fossil record contradict this prediction. The paradox and possible solution are a fascinating combination of astrophysics, relativity and the Earth sciences. Models predict that 4 billion years ago the Sun shone with only 70 % of its present luminosity. Since power P is related to temperature T by the Stefan-Boltzmann Law P ? T4, Earth temperature would have been only 91 % of its present value. That temperature is approximately 283K, so temperature in the past would have been only 258K. Earth's surface would have frozen solid, making evolution of life very unlikely. Geology shows evidence of extensive sedimentation 4 billion years ago. Other geological markers corroborate the presence of liquid water on Earth during this period. Paleontology dates the earliest organisms at least 3.4 to 4 billion years old. Clearly liquid water and life both existed when the model predicts Earth was frozen solid. This conflict with observations is the Faint Young Sun paradox. Fortunately, Relativity and Space/Time can help save the standard solar model. The Sun converts its fuel to energy according to E=mc2. Unified Space/Time predicts that c is given by: GM=tc3. Where t is age of the Universe, GM combines its mass and gravitational constant. Solving, we have c(t)=(GM)^{1/3} t^{-1/3}. Billions of years ago, solar output and temperature were therefore higher than originally calculated. Earth is estimated to be 4.6 billion years and the Universe 13.7 billion years old, 1.5 times its age at the time of Earth's formation. Energy e=mc2 is adjusted by (1.5)^{2/3} = 1.31 times the initial estimate. Multiplying by that estimate of 70 %, the Sun's actual output was 0.917 of the present value. Temperature was then (0.917)^{1/4} = 98 % of today's value. If we start with an estimate of 76 %, the Sun's true output was exactly the present value. The "paradox" leads to an extraordinary confirmation of Theory. The solar constant may indeed be constant, allowing life to have evolved on Earth for billions of years. Prediction of a changing c can be more precisely corroborated using observations of Type Ia supernovae. Earth's temperature provides additional data points to supplement supernova data from a more distant past. This corroborating data distinguishes Theory from "accelerating universe" ideas. Theory also may help determine whether CO2 warmed Earth's temperature in the past. In conclusion, the "Faint Young Sun" is not a problem but a window from the Earth sciences to astrophysics and cosmology. Geology and the fossil record can help verify "fossil" values of fundamental measurements, determining whether those values are indeed constant.

  10. Is the faint young Sun paradox solved?

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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)

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

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas Alexander

    1998-09-01

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

  12. Accurate shear measurement with faint sources

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Luo, Wentao; Foucaud, Sebastien

    2015-01-01

    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.

  13. Observations of faint comets with the IUE

    NASA Astrophysics Data System (ADS)

    Festou, M.

    1982-06-01

    Spectral observations of eight comets, including seven periodic comets, made in the range 1150-3400 A with the IUE satellite are presented. Comet Bradfield, the sole nonperiodic comet observed, is found to exhibit strong OH and atomic hydrogen emissions from the decomposition of water, along with oxygen, carbon, sulfur, carbon disulfide, C2 and CO2(plus) emissions and a faint continuum due to dust at longer wavelengths. Comets Encke, Tuttle and Stefan-Oterma appear to have identical spectra in the UV, showing evidence of much gas, little dust and few ions (only CO2(plus) detected), and differing from comet Bradfield only in the lack of C2 emission. All eight comets observed by IUE, including Seargent, Meier, Borrelly and Panther, had the same chemical composition, consisting mainly of water with a few per mil or per cent CN, C2, C3 and CS. The water production rates of the periodic comets range from levels 6 times less to 11 times more than that of Comet Bradfield, which may be related to nuclear size or cometary age.

  14. Exploring three faint source detections methods for aperture synthesis radio images

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  16. SMA observations on faint submillimeter galaxies with S {sub 850} < 2 mJy: Ultra dusty low-luminosity galaxies at high redshift

    SciTech Connect

    Chen, Chian-Chou; Cowie, Lennox L.; Barger, Amy J.; Williams, Jonathan P. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Wang, Wei-Hao [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2014-07-01

    We obtained Submillimeter Array (SMA) observations of eight faint (intrinsic 850 ?m fluxes < 2 mJy) submillimeter galaxies (SMGs) discovered in SCUBA images of the massive lensing cluster fields A370, A2390, and A1689 and detected five. In total, we obtain five SMA detections, all of which have de-lensed fluxes <1 mJy with estimated total infrared luminosities 10{sup 10}-10{sup 12} L {sub ?}, comparable to luminous infrared galaxies and normal star-forming galaxies. Based on the latest number counts, these galaxies contribute ?70% of the 850 ?m extragalactic background light and represent the dominant star-forming galaxy population in the dusty universe. However, only 40{sub ?16}{sup +30}% of our faint SMGs would be detected in deep optical or near-infrared surveys, which suggests many of these sources are at high redshifts (z ? 3) or extremely dusty, and they are not included in current star formation history estimates.

  17. Looking Deep with Infrared Eyes

    NASA Astrophysics Data System (ADS)

    2006-07-01

    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

  18. ISOCAM 15um Search for Distant Infrared Galaxies Lensed by Clusters

    E-print Network

    Barvainis, R; Helou, G; Barvainis, Richard; Antonucci, Robert

    1999-01-01

    In a search for lensed infrared galaxies, ISOCAM images have been obtained toward the rich clusters Abell 2218 and Abell 2219 at 15um. Nine galaxies (four in Abell 2218 and five in Abell 2219) were detected with flux levels in the range 530-1100 microJy. Three of the galaxies detected in Abell 2218 have previously known redshifts; of these one is a foreground galaxy and the other two are lensed background galaxies at z=0.474 and z=1.032. One of the objects detected in the field of Abell 2219 is a faint, optically red, extreme infrared-dominated galaxy with a probable redshift of 1.048.

  19. ISOCAM 15um Search for Distant Infrared Galaxies Lensed by Clusters

    E-print Network

    Richard Barvainis; Robert Antonucci; George Helou

    1999-05-12

    In a search for lensed infrared galaxies, ISOCAM images have been obtained toward the rich clusters Abell 2218 and Abell 2219 at 15um. Nine galaxies (four in Abell 2218 and five in Abell 2219) were detected with flux levels in the range 530-1100 microJy. Three of the galaxies detected in Abell 2218 have previously known redshifts; of these one is a foreground galaxy and the other two are lensed background galaxies at z=0.474 and z=1.032. One of the objects detected in the field of Abell 2219 is a faint, optically red, extreme infrared-dominated galaxy with a probable redshift of 1.048.

  20. ISOCAM 15 Micron Search for Distant Infrared Galaxies Lensed by Clusters

    NASA Astrophysics Data System (ADS)

    Barvainis, Richard; Antonucci, Robert; Helou, George

    1999-08-01

    In a search for lensed infrared galaxies, ISOCAM images have been obtained toward the rich clusters Abell 2218 and Abell 2219 at 15 mum. Nine galaxies (four in Abell 2218 and five in Abell 2219) were detected with flux levels in the range 530-1100 muJy. Three of the galaxies detected in Abell 2218 have previously known redshifts; of these one is a foreground galaxy, and the other two are lensed background galaxies at z=0.474 and z=1.032. One of the objects detected in the field of Abell 2219 is a faint, optically red, extreme infrared-dominated galaxy with a probable redshift of 1.048.

  1. Near infrared observations of TNOs with SINFONI

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

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

  2. An Extreme-AO Search for Giant Planets around a White Dwarf --VLT/SPHERE performance on a faint target GD 50

    E-print Network

    Xu, S; Wahhaj, Z; Milli, J; Scicluna, P; Bertrang, G H -M

    2015-01-01

    CONTEXT. Little is known about the planetary systems around single white dwarfs although there is strong evidence that they do exist. AIMS. We performed a pilot study with the extreme-AO system on the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the Very Large Telescopes (VLT) to look for giant planets around a young white dwarf, GD 50. METHODS. We were awarded science verification time on the new ESO instrument SPHERE. Observations were made with the InfraRed Dual-band Imager and Spectrograph in classical imaging mode in H band. RESULTS. Despite the faintness of the target (14.2 mag in R band), the AO loop was closed and a strehl of 37\\% was reached in H band. No objects were detected around GD 50. We achieved a 5-sigma contrast of 6.2, 8.0 and 8.25 mags at 0{\\farcs}2, 0{\\farcs}4 and 0{\\farcs}6 and beyond, respectively. We exclude any substellar objects more massive than 4.0 M$_\\textrm{J}$ at 6.2 AU, 2.9 M$_\\textrm{J}$ at 12.4 AU and 2.8 M$_\\textrm{J}$ at 18.6 AU and beyond. This is the ...

  3. Spectroscopy of Kuiper Belt Objects and Centaurs

    NASA Astrophysics Data System (ADS)

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

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

  4. SN 2009E: a faint clone of SN 1987A

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

  5. Merged infrared catalogue

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  6. The Infrared Hunter

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [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.

  7. On the angular correlation function of faint galaxies

    NASA Astrophysics Data System (ADS)

    Yoshii, Yuzuru; Peterson, Bruce A.; Takahara, Fumio

    1993-09-01

    Predictions of the angular two-point correlation function of faint galaxies, that are consistent with N-body simulations of clustering evolution and with the redshift distribution of faint galaxies obtained when selection effects are taken into account, are presented for various model universes. We find that the clustering amplitude is not a monotonic function of the cosmological parameters, exhibiting a complicated dependence on the model universe. It is found that recent measurements of the small-scale angular correlation of faint galaxies are consistent with both a flat CDM-dominated universe and a flat vacuum-dominated universe. Increasing the bias and/or lowering Omega0 with a vanishing cosmological constant gives high clustering amplitudes in excess of the observed level, and these models are incompatible with the observations. The conclusion drawn by Efstathiou et al. (1991) that the gravitational clustering in a flat CDM universe conflicts with their data is not justified.

  8. Flickering Faint Galaxies: Few and Far Between

    NASA Astrophysics Data System (ADS)

    Kochanski, Greg P.; Tyson, J. Anthony; Fischer, Philippe

    1996-04-01

    Optical variability in galaxies at high redshift is a tracer of evolution in AGN activity, and should provide a useful constraint on models of galaxy evolution, AGN structure, and cosmology. We studied optical variability in multiple deep GCD and photographic surveys of blank fields for galaxies with B_j_ = 20-25 mag. Weakly variable objects are far more common than strongly variable ones. For objects near B_j_ = 22, 0.74% +/- 0.2% vary by 0.026 mag rms or more, over a decade. This is small compared with previous claims based on photographic surveys, and also small compared with the fraction of bright quasars (5% at B_j_= 20 mag) or Seyferts (~1% -2% for B_j_ < 18). The fraction of objects that vary increases slowly with magnitude. Detection probabilities and error rates were checked by simulations and statistical analysis of fluctuations of sample sky spots.

  9. Deep optical imaging of the field of PC 1643+4631A&B - I. Spatial distributions and the counts of faint galaxies

    NASA Astrophysics Data System (ADS)

    Haynes, Toby; Cotter, Garret; Baker, Joanne C.; Eales, Steve; Jones, Michael E.; Rawlings, Steve; Saunders, Richard

    2002-08-01

    We present deep optical images of the PC 1643+4631 field, obtained at the William Herschel Telescope (WHT). This field contains two quasars at redshifts z=3.79 and 3.83 and a cosmic microwave background (CMB) decrement detected with the Ryle Telescope. The images are in U, G, V, R and I filters, and in two custom-built narrow-band filters. Using the object-finding algorithms FOCAS and SEXTRACTOR, we have constructed galaxy catalogues in each band. The catalogues created with the two detection algorithms are compared to determine the faint magnitude limits to which they are consistent. Using Monte Carlo simulations, we investigate the completeness of the catalogues at faint magnitudes. In particular, we compare the flux lost using isophotal apertures on a real image with that on a noise-only image: recovery of artificial galaxies from the noise-only image significantly overestimates the flux lost from the galaxies, and we find that the corrections made using this technique suffer a systematic error of some 0.4mag. We determine that the catalogues are complete to RAB, GAB=25.0 and to UAB=25.5, and we investigate the number counts and spatial distributions of the galaxies in the field. The galaxy counts in each band are consistent with the results of other recent deep imaging surveys. We investigate the properties of several populations of objects in the field. Our narrow-band imaging does not reveal the presence of any bright emission-line galaxies, nor do we detect any obvious candidate for a further, possibly lensed, quasar image. The galaxies whose colours indicate that they lie at redshifts 1<~z<~2 are found to have similar properties as in other fields. However, we find that the number of high-redshift Lyman-break candidate galaxies in the field is significantly higher than would be expected from the mean surface density found in the surveys of Steidel et al. The Lyman-break candidates are strongly clustered, but they are not concentrated towards the CMB decrement; rather, they tend to lie towards the edges of the field. Finally, using the present data in combination with existing near-infrared imaging of the field, we investigate extremely red objects (EROs) in the field. We find a large surface density of EROs, and we find that their colours are consistent with those of slightly-reddened early-type galaxies at redshift z~2.

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

    NASA Astrophysics Data System (ADS)

    Hirschauer, Alec S.; Salzer, John J.

    2015-01-01

    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.

  11. 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

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

    2013-01-01

    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

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

    Microsoft Academic Search

    John B. Adams

    1974-01-01

    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

  13. Faint 6.7um Galaxies and their Contributions to the Stellar Mass Density in the Universe

    E-print Network

    Yasunori Sato; Lennox L. Cowie; Kimiaki Kawara; Hideo Matsuhara; Haruyuki Okuda; David B. Sanders; Yoshiaki Sofue; Yoshiaki Taniguchi; Ken-ichi Wakamatsu

    2003-12-04

    We discuss the nature of faint 6.7um galaxies detected with the mid-infrared camera ISOCAM on board the Infrared Space Observatory (ISO). The 23 hour integration on the Hawaii Deep Field SSA13 has provided a sample of 65 sources down to 6uJy at 6.7um. For 57 sources, optical or near-infrared counterparts were found with a statistical method. All four Chandra sources, three SCUBA sources, and one VLA/FIRST source in this field were detected at 6.7um with high significance. Using their optical to mid-infrared colors, we divided the 6.7um sample into three categories: low redshift galaxies with past histories of rapid star formation, high redshift ancestors of these, and other star forming galaxies. Rapidly star forming systems at high redshifts dominate the faintest end. Spectroscopically calibrated photometric redshifts were derived from fits to a limited set of template SEDs. They show a high redshift tail in their distribution with faint (1. The 6.7um galaxies tend to have brighter K magnitudes and redder I-K colors than the blue dwarf population at intermediate redshifts. Stellar masses of the 6.7um galaxies were estimated from their rest-frame near-infrared luminosities. Massive galaxies (M_star~10e11M_sun) were found in the redshift range of z=0.2-3. Epoch dependent stellar mass functions indicate a decline of massive galaxies' comoving space densities with redshift. Even with such a decrease, the contributions of the 6.7um galaxies to the stellar mass density in the universe are found to be comparable to those expected from UV bright galaxies detected in deep optical surveys.

  14. NATURE AND EVOLUTION OF FAINT RADIO SOURCE POPULATIONS

    E-print Network

    Waddington, Ian

    concentrated on the numerous faint blue galaxies (``FBG's'') seen in deep ground­based CCD images (e.g., [44 radio galaxies. E/S0 and Sabc galaxies have evolved little since z'1, while the FBG counts are dominated

  15. CONFIRMATION OF FAINT DWARF GALAXIES IN THE M81 GROUP

    SciTech Connect

    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

    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.

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

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

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

  17. Infrared fiber optics

    Microsoft Academic Search

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

    1979-01-01

    This interim technical report summarizes the first year's research efforts to fabricate optical communications fibers that are transmissive between 1 and 12 micrometers. The ultimate objective of this program is to prepare infrared transmitting fibers with losses less than 5 dB\\/km. In preparing infrared transparent fibers with these losses, we are emphasizing the extrusion into fiber of very pure KCl

  18. LOITA: Lunar Optical/Infrared Telescope Array

    NASA Technical Reports Server (NTRS)

    1993-01-01

    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.

  19. An extreme-AO search for giant planets around a white dwarf. VLT/SPHERE performance on a faint target GD 50

    NASA Astrophysics Data System (ADS)

    Xu, S.; Ertel, S.; Wahhaj, Z.; Milli, J.; Scicluna, P.; Bertrang, G. H.-M.

    2015-07-01

    Context. Little is known about the planetary systems around single white dwarfs, although there is strong evidence that they do exist. Aims: We performed a pilot study with the extreme-AO system on the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the Very Large Telescopes (VLT) to look for giant planets around a young white dwarf, GD 50. Methods: We were awarded science verification time on the new ESO instrument SPHERE. Observations were made with the InfraRed Dual-band Imager and Spectrograph in classical imaging mode in H band. Results: Despite the faintness of the target (14.2 mag in R band), the AO loop was closed and a strehl of 37% was reached in H band. No objects were detected around GD 50. We achieved a 5-sigma contrast of 6.2, 8.0, and 8.25 mag at 0.?2, 0.?4, and 0.?6 and beyond, respectively. We exclude any substellar objects more massive than 4.0 MJ at 6.2 au, 2.9 MJ at 12.4 au, and 2.8 MJ at 18.6 au and beyond. This rivals the previous upper limit set by Spitzer. We further show that SPHERE is the most promising instrument available to search for close-in substellar objects around nearby white dwarfs. Based on observations made with European Southern Observatory (ESO) telescopes at the La Silla Paranal Observatory under program 60.A-9373(A).Figure 4 is available in electronic form at http://www.aanda.org

  20. Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

  1. Mid-Infrared Diagnostics of LINERs

    E-print Network

    E. Sturm; D. Rupke; A. Contursi; D. -C. Kim; D. Lutz; H. Netzer; S. Veilleux; R. Genzel; M. Lehnert; L. J. Tacconi; D. Maoz; J. Mazzarella; S. Lord; D. Sanders; A. Sternberg

    2006-10-26

    We report results from the first mid-infrared spectroscopic study of a comprehensive sample of 33 LINERs, observed with the Spitzer Space Telescope. We compare the properties of two different LINER populations: infrared-faint LINERs, with LINER emission arising mostly in compact nuclear regions, and infrared-luminous LINERs, which often show spatially extended (non-AGN) LINER emission. We show that these two populations can be easily distinguished by their mid-infrared spectra in three different ways: (i) their mid-IR spectral energy distributions (SEDs), (ii) the emission features of polycyclic aromatic hydrocarbons (PAHs), and (iii) various combinations of IR fine-structure line ratios. IR-luminous LINERs show mid-IR SEDs typical of starburst galaxies, while the mid-IR SEDs of IR-faint LINERs are much bluer. PAH flux ratios are significantly different in the two groups. Fine structure emission lines from highly excited gas, such as [O IV], are detected in both populations, suggesting the presence of an additional AGN also in a large fraction of IR-bright LINERs, which contributes little to the combined mid-IR light. The two LINER groups occupy different regions of mid-infrared emission-line excitation diagrams. The positions of the various LINER types in our diagnostic diagrams provide important clues regarding the power source of each LINER type. Most of these mid-infrared diagnostics can be applied at low spectral resolution, making AGN- and starburst-excited LINERs distinguishable also at high redshifts.

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

    E-print Network

    Lu, Tiao

    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

  3. Two Magellanic Cloud Star-Forming Clusters from Optical to Infrared

    NASA Astrophysics Data System (ADS)

    Romita, Krista; Carlson, L. R.; Sewilo, M.; Meixner, M.; Sabbi, E.; Gordon, K.; Nota, A.; Sirianni, M.; Smith, L. J.; Leither, C.; Hora, J. L.; Robitaille, T.; Whitney, B.; Block, M.; Engelbracht, C.; Misselt, K.; Indebetouw, R.; Kato, D.; Gallagher, J. S.; Babler, B.; Meade, M.; Oey, M. S.; Cignoni, M.; Tosi, M.; Vijh, U.; Walterbos, R.

    2010-01-01

    We present analysis of the young stellar and proto-stellar populations in star-forming clusters NGC 602 in the SMC and N206 (Henize 206) in the LMC. Deep, photometric data over the wavelength range 0.36 to 24 ?m allow us to probe stellar populations and recent star formation using a combination of Color-Magnitude Diagram analysis, model Spectral Energy Distribution fitting, and image inspection. We combine both ground- and space-based observations to develop a more complete picture of star formation and its progression in these regions, from embedded, infrared bright YSOs (Young Stellar Objects) to faint optical Pre-Main Sequence sources to optically bright O and B type stars. Infrared data are drawn from the Spitzer Legacy Projects Surveying the Agents of a Galaxy's Evolution (SAGE-LMC and SAGE-SMC). Near infrared data are from InfraRed Survey Facility (IRSF) Magellanic Clouds Point Source Catalog of Kato, et al. (2007). N206 optical data are taken from the Magellanic Cloud Photometric Survey (MCPS), and NGC 602 optical data are from Hubble/ACS (Advanced Camera for Surveys) and ground-based SMARTS (Small and Moderate Aperture Research Telescope System) observations. The SAGE Project is supported by NASA/Spitzer grant 1275598 and NASA NAG5-12595.

  4. Radio loud far-infrared galaxies

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  5. Spitzer Mid-Infrared Spectroscopy of 70um-Selected Distant Luminous Infrared Galaxies

    E-print Network

    Kate Brand; Dan W. Weedman; Vandana Desai; Emeric Le Floc'h; Lee Armus; Arjun Dey; Jim R. Houck; Buell T. Jannuzi; Howard A. Smith; B. T. Soifer

    2007-09-20

    We present mid-infrared spectroscopy obtained with the Spitzer Space Telescope of a sample of 11 optically faint, infrared luminous galaxies selected from a Spitzer MIPS 70um imaging survey of the NDWFS Bootes field. These are the first Spitzer IRS spectra presented of distant 70um-selected sources. All the galaxies lie at redshifts 0.3infrared luminosities of L_IR~ 0.1-17 x 10^12 solar luminosities. Seven of the galaxies exhibit strong emission features attributed to polycyclic aromatic hydrocarbons (PAHs). The average IRS spectrum of these sources is characteristic of classical starburst galaxies, but with much larger infrared luminosities. The PAH luminosities of L(7.7) ~ 0.4 - 7 x 10^11 solar luminosities imply star formation rates of ~ 40 - 720 solar masses per year. Four of the galaxies show deep 9.7um silicate absorption features and no significant PAH emission features (6.2um equivalent widths infrared luminosities and low f70/f24 flux density ratios suggests that these sources have AGN as the dominant origin of their large mid-infrared luminosities, although deeply embedded but luminous starbursts cannot be ruled out. If the absorbed sources are AGN-dominated, a significant fraction of all far-infrared bright, optically faint sources may be dominated by AGN.

  6. Diffraction-limited CCD imaging with faint reference stars

    Microsoft Academic Search

    R. N. Tubbs; J. E. Baldwin; C. D. Mackay; G. C. Cox

    2002-01-01

    By selecting short exposure images taken using a CCD with negligible readout\\u000anoise we obtained essentially diffraction-limited 810 nm images of faint\\u000aobjects using nearby reference stars brighter than I=16 at a 2.56 m telescope.\\u000aThe FWHM of the isoplanatic patch for the technique is found to be 50\\u000aarcseconds, providing ~20% sky coverage around suitable reference stars.

  7. The morphological identification of the rapidly evolving population of faint galaxies

    E-print Network

    Karl Glazebrook; Richard Ellis; Basilio Santiago; Richard Griffiths

    1995-03-28

    The excess numbers of blue galaxies at faint magnitudes are a long-standing cosmological puzzle. We present new number-magnitude counts as a function of galactic morphology from the first deep fields of the Cycle 4 Hubble Space Telescope {\\it Medium Deep Survey} project. From a sample of 301 galaxies we define counts for elliptical, spiral and irregular/peculiar galaxies to $I=22$. We find two principal results. Firstly the elliptical and spiral galaxy counts both follow the predictions of high-normalisation no-evolution models at all magnitudes, indicating that regular Hubble types evolve only slowly to $z\\sim 0.5$. Secondly we find that irregular/peculiar galaxies, including multiple-peaked, possibly merging, objects, have a very steep number-magnitude relation and greatly exceed predictions based on proportions in local surveys. These systems make up half the total counts by $I=22$ and imply the rapidly-evolving component of the faint galaxy population has been identified.

  8. Star/galaxy separation at faint magnitudes: application to a simulated Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Soumagnac, M. T.; Abdalla, F. B.; Lahav, O.; Kirk, D.; Sevilla, I.; Bertin, E.; Rowe, B. T. P.; Annis, J.; Busha, M. T.; Da Costa, L. N.; Frieman, J. A.; Gaztanaga, E.; Jarvis, M.; Lin, H.; Percival, W. J.; Santiago, B. X.; Sabiu, C. G.; Wechsler, R. H.; Wolz, L.; Yanny, B.

    2015-06-01

    We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the gravitational weak lensing and large-scale structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by point spread function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper. We first use principal component analysis to outline the correlations between the objects parameters and extract from it the most relevant information. We then use the reduced set of parameters as input to an Artificial Neural Network. This multiparameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SEXTRACTOR), especially at faint magnitudes: it increases the purity by up to 20 per cent for stars and by up to 12 per cent for galaxies, at i-magnitude fainter than 23.

  9. The First Science Flight of the Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL)

    NASA Astrophysics Data System (ADS)

    Martin, Christopher; Milliard, Bruno; Schiminovich, David; Tuttle, Sarah; Matuszewski, Matt; Rahman, Shahin; Evrard, Jean; Frank, Stephan; Deharveng, Jean-Michel; Peroux, Celine

    We have completed the second flight of the path-finding experiment, the Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL), designed to discover and map faint emis-sion from the Intergalactic Medium (IGM). The second flight was fully successful, proving a fully functional fine pointing gondola with arcsec level capability, a 1 meter diameter (fixed) parabola primary telescope with planar sidereostat for pointing, a complete closed loop guide camera and control software, and a fiber fed UV integral field spectrograph feeding a spare GALEX Near UV detector. Three scientific targets were observed, and analysis of the data shows that the instrument performed as expected. The flux measurements obtained will be compared to models for IGM emission. We discuss future modifications to the payload that will achieve a 10-to 30-fold increase in sensitivity over science flight 1. We also discuss other instrument configurations that can utilize the 1-meter UV telescope and arcsecond pointing platform, and their corresponding science objectives. FIREBALL is a collaboration of NASA, Caltech, Columbia University, CNES, and Laboratorie Astrophysique Marseille, and is sup-ported by NASA, CNES, and CNRS.

  10. Faint blue counts from formation of dwarf galaxies at z approximately equals 1

    NASA Technical Reports Server (NTRS)

    Babul, Arif; Rees, Martin J.

    1993-01-01

    The nature of faint blue objects (FBO's) has been a source of much speculation since their detection in deep CCD images of the sky. Their high surface density argues against them being progenitors of present-day bright galaxies and since they are only weakly clustered on small scales, they cannot be entities that merged together to form present-day galaxies. Babul & Rees (1992) have suggested that the observed faint blue counts may be due to dwarf elliptical galaxies undergoing their initial starburst at z is approximately equal to 1. In generic hierarchical clustering scenarios, however, dwarf galaxy halos (M is approximately 10(exp 9) solar mass) are expected to form at an earlier epoch; for example, typical 10(exp 9) solar mass halos will virialize at z is approximately equal to 2.3 if the power-spectrum for the density fluctuations is that of the standard b = 2 cold dark matter (CDM) model. Under 'ordinary conditions' the gas would rapidly cool, collect in the cores, and undergo star-formation. Conditions at high redshifts are far from 'ordinary'. The intense UV background will prevent the gas in the dwarf halos from cooling, the halos being released from their suspended state only when the UV flux has diminished sufficiently.

  11. Optical Selection of Faint AGN in the COSMOS Field

    E-print Network

    C. M. Casey; C. D. Impey; J. R. Trump; J. Gabor; R. G. Abraham; P. Capak; N. Z. Scoville; M. Brusa; E. Schinnerer

    2008-02-20

    We outline a strategy to select faint (iCOSMOS field, picking candidates by their nonstellar colors in broadband ground-based photometry and morphological properties extracted from HST-ACS. AGN optical color selection has not been applied to such faint magnitudes in such a large continuous part of the sky. Hot stars are known to be the dominant contaminant for bright AGN candidate selection at zCOSMOS field infer stellar contamination. We use 292 spectroscopically confirmed type 1 AGN and quasar templates to predict AGN colors with redshift, and contrast those predictions with the colors of known contaminating populations. The motivation of this study and subsequent spectroscopic follow-up is to populate and refine the faint end of the QLF where the population of type 1 AGN is presently not well known. The anticipated AGN observations will add to the ~300 already known AGN in the COSMOS field, making COSMOS a densely packed field of quasars to be used to understand supermassive black holes and probe the structure of the intergalactic medium in the intervening volume.

  12. Can waterbelt climates resolve the faint young Sun paradox?

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  13. HST ultraviolet spectral energy distributions for three ultraluminous infrared galaxies

    E-print Network

    Neil Trentham; John Kormendy; David Sanders

    1999-01-28

    We present HST Faint Object Camera ultraviolet (230 nm and 140 nm) images of three ultraluminous infrared galaxies (ULIG: L_ir > 10^12 L_sun) selected from the IRAS Revised Bright Galaxy Sample. The purpose is to estimate spectral energy distributions (SEDs) to facilitate the identification of similar objects at high redshift in deep optical, infrared, and submm surveys. All three galaxies (VII Zw031 = IRAS F12112+0305, and IRAS F22491-1808) were well detected at 230 nm. Two of the three were marginally detected at 140 nm. The fluxes, together with ground-based optical and infrared photometry, are used to compute SEDs over a wide wavelength range. The measured SEDs drop from the optical to the ultraviolet, but the magnitude of the drop ranges from a factor of ~3 in IRAS F22491-1808 to a factor of ~100 in VIIZw031. This is most likely due to different internal extinctions. Such an interpretation is also suggested by extrapolating to ultraviolet wavelengths the optical internal extinction measured in VIIZw031. K-corrections are calculated to determine the colors of the sample galaxies as seen at high redshifts. Galaxies like VIIZw031 have very low observed rest-frame UV fluxes which means that such galaxies at high redshift will be extremely red or even missing in optical surveys. On the other hand, galaxies like IRAS F12112+0305 and IRAS F22491-1808, if seen at high redshift, would be sufficiently blue that they would not easily be distinguished from normal field galaxies, and therefore, identified as ULIGs. The implication is then that submillimeter surveys may be the only means of properly identifying the majority of ULIGs at high redshift.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  15. Infrared Investigations.

    ERIC Educational Resources Information Center

    Lascours, Jean; Albe, Virginie

    2001-01-01

    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)

  16. Infrared Investigations

    NSDL National Science Digital Library

    2013-08-30

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

  17. The 12 ?m ISO-ESO-Sculptor and 24 ?m Spitzer faint counts reveal a population of ULIRGs as dusty massive ellipticals. Evolution by types and cosmic star formation

    NASA Astrophysics Data System (ADS)

    Rocca-Volmerange, B.; de Lapparent, V.; Seymour, N.; Fioc, M.

    2007-12-01

    Context: Multi-wavelength galaxy number counts provide clues to the nature of galaxy evolution. The interpretation per galaxy type of the mid-IR faint counts obtained with ISO and Spitzer, consistent with the analysis of deep UV-optical-near IR galaxy counts, provide new constraints on the dust and stellar emission. Discovering the nature of new populations, such as high redshift ultra-luminous (?1012~L?) infrared galaxies (ULIRGs), is also crucial for understanding galaxy evolution at high redshifts. Aims: We first present the faint galaxy counts at 12 ?m from the catalogue of the ISO-ESO-Sculptor Survey (ISO-ESS) published in a companion article (Seymour et al. 2007a, A&A, 475, 791). They go down to 0.31 mJy after corrections for incompleteness. We verify the consistency with the existing ISO number counts at 15 ?m. Then we analyse the 12 ?m (ISO-ESS) and the 24 ?m (Spitzer) faint counts, to constrain the nature of ULIRGs, the cosmic star formation history and time scales for mass buildup. Methods: We show that the “normal” scenarios in our evolutionary code PÉGASE, which had previously fitted the deep UV-optical-near IR counts, are unsuccessful at 12 ?m and 24 ?m. We thus propose a new ULIRG scenario adjusted to the observed cumulative and differential 12 ?m and 24 ?m counts and based on observed 12 ?m and 25 ?m IRAS luminosity functions and evolutionary optical/mid-IR colours from PÉGASE. Results: We succeed in simultaneously modelling the typical excess observed at 12 ?m, 15 ?m (ISO), and 24 ?m (Spitzer) in the cumulative and differential counts by only changing 9% of normal galaxies (1/3 of the ellipticals) into ultra-bright dusty galaxies evolving as ellipticals, and interpreted as distant ULIRGs. These objects present similarities with the population of radio-galaxy hosts at high redshift. No number density evolution is included in our models even if minor starbursts due to galaxy interactions remain compatible with our results. Conclusions: Higher spectral and spatial resolution in the mid-IR, together with submillimeter observations using the future Herschel observatory, will be useful to confirm these results. Based on observations with ISO, an ESA project with instruments funded by ESA member states (specially the PI countries France, Germany, The Netherlands, and the United Kingdom) with the participation of ISAS and NASA. The ESO-Sculptor Survey is based on observations collected at the European Southern Observatory (ESO), La Silla, Chile.

  18. A Classification Scheme for Young Stellar Objects Using the WIDE-FIELD INFRARED SURVEY EXPLORER ALLWISE Catalog: Revealing Low-Density Star Formation in the Outer Galaxy

    NASA Technical Reports Server (NTRS)

    Koening, X. P.; Leisawitz, D. T.

    2014-01-01

    We present an assessment of the performance of WISE and the AllWISE data release in a section of the Galactic Plane. We lay out an approach to increasing the reliability of point source photometry extracted from the AllWISE catalog in Galactic Plane regions using parameters provided in the catalog. We use the resulting catalog to construct a new, revised young star detection and classification scheme combining WISE and 2MASS near and mid-infrared colors and magnitudes and test it in a section of the Outer Milky Way. The clustering properties of the candidate Class I and II stars using a nearest neighbor density calculation and the two-point correlation function suggest that the majority of stars do form in massive star forming regions, and any isolated mode of star formation is at most a small fraction of the total star forming output of the Galaxy. We also show that the isolated component may be very small and could represent the tail end of a single mechanism of star formation in line with models of molecular cloud collapse with supersonic turbulence and not a separate mode all to itself.

  19. Adaptive Optics Imaging of Faint Companions: Test Case of MWC480

    NASA Astrophysics Data System (ADS)

    Close, Laird; Potter, Dan; Tokunaga, Alan

    We briefly describe how diffraction-limited imaging with adaptive optics (AO) can detect young massive brown dwarfs by direct imaging. We will review how current curvature AO systems can already detect point sources 1 million times fainter at separations of 3 arcsec in median seeing (0.65 arcsec). We will show real examples of such detections made with the University of Hawaii AO system located at CFHT on Mauna Kea around the young (2 Myr) nearby (132 pc) Herbig Ae/Be star MWC480. Moreover, we show that the 4 faint (H=18-19) companions within 6 arcsec of MWC480 are unlikely to be physical since they are non-common proper motion objects, and so are likely just background stars.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  1. Discovery of a Faint Old Stellar System at 150 kpc

    Microsoft Academic Search

    T. Sakamoto; T. Hasegawa

    2006-01-01

    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

  2. On the Poisson Approximation to Photon Distribution for Faint Lasers

    E-print Network

    Yucheng Hu; Xiang Peng; Tiejun Li; Hong Guo

    2006-09-23

    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.

  3. Near-infrared counterparts to the Galactic Bulge Survey X-ray source population

    NASA Astrophysics Data System (ADS)

    Greiss, S.; Steeghs, D.; Jonker, P. G.; Torres, M. A. P.; Maccarone, T. J.; Hynes, R. I.; Britt, C. T.; Nelemans, G.; Gänsicke, B. T.

    2014-03-01

    We report on the near-infrared matches, drawn from three surveys, to the 1640 unique X-ray sources detected by Chandra in the Galactic Bulge Survey (GBS). This survey targets faint X-ray sources in the bulge, with a particular focus on accreting compact objects. We present all viable counterpart candidates and associate a false alarm probability (FAP) to each near-infrared match in order to identify the most likely counterparts. The FAP takes into account a statistical study involving a chance alignment test, as well as considering the positional accuracy of the individual X-ray sources. We find that although the star density in the bulge is very high, ˜90 per cent of our sources have an FAP <10 per cent, indicating that for most X-ray sources, viable near-infrared counterparts candidates can be identified. In addition to the FAP, we provide positional and photometric information for candidate counterparts to ˜95 per cent of the GBS X-ray sources. This information in combination with optical photometry, spectroscopy and variability constraints will be crucial to characterize and classify secure counterparts.

  4. Infrared spectrum of an extremely cool white-dwarf star

    PubMed

    Hodgkin; Oppenheimer; Hambly; Jameson; Smartt; Steele

    2000-01-01

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

  5. Adaptive Optics Imaging Survey of Luminous Infrared Galaxies

    SciTech Connect

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

    2006-03-13

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  7. Orientations of very faint galaxies in the Coma cluster

    E-print Network

    C. Adami; R. Gavazzi; J. C. Cuillandre; F. Durret; O. Ilbert; A. Mazure; R. Pello; M. P. Ulmer

    2008-10-02

    We have then searched for preferential orientations of faint galaxies in the Coma cluster (down I_Vega~-11.5). By applying a deconvolution method to deep u* and I band images of the Coma cluster, we were able to recover orientations down to faint magnitudes. No preferential orientations are found in more than 95% of the cluster, and the brighter the galaxies, the fewer preferential orientations. The minor axes of late type galaxies are radially oriented along a northeast -southwest direction and are oriented north-south in the western X-ray sub- structures. For early type galaxies, in the western regions showing significant preferential orientations, galaxy major axes are oriented perpendicularly to the north-south direction. In the eastern significant region and close to NGC 4889, galaxy major axes also point toward the 2 cluster dominant galaxies. In the southern significant regions, galaxy planes are tangential with respect to the clustercentric direction, except close to (alpha=194.8, delta=27.65) where the orientation is close to -15deg. Part of the orientations of the minor axes of late type galaxies and of the major axes of early type galaxies can be explained by a tidal torque model applied to cosmological filaments and local merging directions. Another part (close to NGC4889) can be accounted for by collimated infalls. For early type galaxies, the (alpha=194.8, delta=27.65) region shows orientations that probably result from processes involving induced star formation.

  8. EMISSION LINE PROPERTIES ACTIVE GALACTIC NUCLEI FROM PRECOSTAR FAINT OBJECT SPECTROGRAPH HUBBLE SPACE TELESCOPE SPECTRAL ATLAS

    E-print Network

    Green, Paul

    /optical emission some most detailed information obtainable about intrinsic properties quasars. Studies of density, ionization metal abundance gas accreting black hole probed through an intriguing poorly understood complex of correlations between emission lines and overall quasar spectral energy distributions that su#ered from

  9. Spectral Analysis of Faint Astronomical Objects: Bayesian Modeling, Computation, and Inference

    E-print Network

    van Dyk, David

    Image Credits" NASA/CXC/NCSU/S.Reynolds et al. 8 #12;Outline of Presentation This talk has two 16 18 20 22 0400800 wavelength (A) photoncount Images may exhibit Spectral, Temporal, and Spatial;Scientific Context The Chandra X-Ray Observatory · Chandra produces images at least thirty times sharper

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

    NASA Technical Reports Server (NTRS)

    Harms, Richard

    1994-01-01

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

  11. An ISOCAM survey through gravitationally lensing galaxy clusters. III. New results from mid-infrared observations of th e cluster Abell 2219

    E-print Network

    D. Coia; L. Metcalfe; B. McBreen; A. Biviano; I. Smail; B. Altieri; J. -P. Kneib; S. McBreen; C. Sanchez-Fernandez; B. O'Halloran

    2006-10-20

    The massive cluster of galaxies Abell 2219 (z = 0.228) was observed at 14.3 $\\mu$m with the Infrared Space Observatory and results were published by Barvainis et al. (1999). These observations have been reanalyzed using a method specifically designed for the detection of faint sources that had been applied to other clusters. Five new sources were detected and the resulting cumulative total of ten sources all have optical counterparts. The mid-infrared sources are identified with three cluster members, three foreground galaxies, an Extremely Red Object, a star and two galaxies of unknown redshift. The spectral energy distributions (SEDs) of the galaxies are fit with models from a selection, using the program GRASIL. Best-fits are obtained, in general, with models of galaxies with ongoing star formation. For three cluster members the infrared luminosities derived from the model SEDs are between ~5.7x10^10 Lsun and 1.4x10^11 Lsun, corresponding to infrared star formation rates between 10 and 24 Msun yr^-1. The two cluster galaxies that have optical classifications are in the Butcher-Oemler region of the color-magnitude diagramme. The three foreground galaxies have infrared luminosities between 1.5x10^10 Lsun and 9.4x10^10 Lsun yielding infrared star formation rates between 3 and 16 Msun yr^-1. Two of the foreground galaxies are located in two foreground galaxy enhancements (Boschin et al. 2004). Including Abell 2219, six distant clusters of galaxies have been mapped with ISOCAM and luminous infrared galaxies (LIRGs) have been found in three of them. The presence of LIRGs in Abell 2219 strengthens the association between luminous infrared galaxies in clusters and recent or ongoing cluster merger activity.

  12. Object extraction Object extraction

    E-print Network

    Giger, Christine

    (is a grass-roof a vegetation area?) · object ontologies are hierarchical (tree / forrest / vegetation · buildings · vegetation · roads #12;Interactive object extraction #12;Interactive object extraction angles in man-made structures · measurement accuracy of human operator is lower than that of automatic

  13. 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)

    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

    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.

  14. 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)

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

    2014-12-01

    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.

  15. SPITZER/INFRARED ARRAY CAMERA LIMITS TO PLANETARY COMPANIONS OF FOMALHAUT AND {epsilon} ERIDANI

    SciTech Connect

    Marengo, Massimo; Hora, Joseph L.; Fazio, Giovanni G.; Schuster, Michael T. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stapelfeldt, Karl; Werner, Michael W. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Carson, Joseph C. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Megeath, S. Thomas [University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States)], E-mail: mmarengo@cfa.harvard.edu

    2009-08-01

    Fomalhaut and {epsilon} Eridani are two young, nearby stars that possess extended debris disks whose structures suggest the presence of perturbing planetary objects. With its high sensitivity and stable point-spread function, Spitzer/Infrared Array Camera (IRAC) is uniquely capable of detecting cool, Jupiter-like planetary companions whose peak emission is predicted to occur near 4.5 {mu}m. We report on deep IRAC imaging of these two stars, taken at 3.6 and 4.5 {mu}m using subarray mode and in all four channels in wider-field full array mode. Observations acquired at two different telescope roll angles allowed faint surrounding objects to be separated from the stellar diffraction pattern. No companion candidates were detected at the reported position of Fomalhaut b with 3{sigma} model-dependent mass upper limits of 3M {sub J} (for an age of 200 Myr). Around {epsilon} Eridani, we instead set a limit of 4 and {approx}<1M {sub J} (1 Gyr model age) at the inner and outer edge of the submillimeter debris ring, respectively. These results are consistent with non-detections in recent near-infrared imaging searches, and set the strongest limits to date on the presence of planets outside {epsilon} Eridani submillimeter ring.

  16. Keck spectroscopy of faint 3 < z < 7 Lyman break galaxies - I. New constraints on cosmic reionization from the luminosity and redshift-dependent fraction of Lyman ? emission

    NASA Astrophysics Data System (ADS)

    Stark, Daniel P.; Ellis, Richard S.; Chiu, Kuenley; Ouchi, Masami; Bunker, Andrew

    2010-11-01

    We present the first results of a new Keck spectroscopic survey of UV faint Lyman break galaxies in the redshift range 3 < z < 7. Combined with earlier Keck and published European Southern Observatory (ESO) VLT data, our spectroscopic sample contains more than 600 dropouts offering new insight into the nature of sub-L* sources typical of those likely to dominate the cosmic reionization process. In this first paper, in a series discussing these observations, we characterize the fraction of strong Ly? emitters within the continuum-selected dropout population. By quantifying how the `Ly? fraction', xLy?, varies with redshift, we seek to constrain changes in Ly? transmission associated with reionization. In order to distinguish the effects of reionization from other factors which affect the Ly? fraction [e.g. dust, interstellar medium (ISM) kinematics], we study the luminosity and redshift-dependence of the Ly? fraction over 3 <~ z <~ 6, when the intergalactic medium (IGM) is known to be ionized. These results reveal that low-luminosity galaxies show strong Ly? emission much more frequently (xLy? = 0.47 +/- 0.16 at MUV = -19) than luminous systems (xLy? = 0.08 +/- 0.02 at MUV = -21), and that at fixed luminosity, the prevalence of strong Lyman ? emission increases moderately with redshift over 3 < z < 6 (d xLy?/d z = 0.05 +/- 0.03). Based on the bluer mean UV slopes of the strong Ly? emitting galaxies in our data set (Ly? - noLy? = -0.33 +/- 0.09 at MUV = -20.5) we argue that the Ly? fraction trends are governed by redshift and luminosity-dependent variations in the dust obscuration, with likely additional contributions from trends in the kinematics and covering fraction of neutral hydrogen. Using the limited infrared spectroscopy of candidate z ~= 7 galaxies, we find a tentative decrease in the Ly? fraction by a factor of >1.9 with respect to the predicted z ~= 7 value, a result which, if confirmed with future surveys, would suggest an increase in the neutral fraction by this epoch. Given the abundant supply of z and Y drops now available from deep Hubble WFC3/IR surveys, we show it will soon be possible to significantly improve estimates of the Ly? fraction using optical and near-infrared multi-object spectrographs, thereby extending the study conducted in this paper to 7 <~ z <~ 8.

  17. A POSSIBLE LOCAL COUNTERPART TO THE EXCESS POPULATION OF FAINT BLUE GALAXIES

    E-print Network

    McGaugh, Stacy

    A POSSIBLE LOCAL COUNTERPART TO THE EXCESS POPULATION OF FAINT BLUE GALAXIES STACY S. MCGAUGH of galaxies to very faint magnitudes have revealed a popu- lation of blue galaxies at intermediate redshift1 5 brightness galaxies have properties very similar to those of the excess blue population10;11, and re- cent

  18. Big Fish, Little Fish: Two New Ultra-faint Satellites of the Milky Way

    Microsoft Academic Search

    V. Belokurov; M. G. Walker; N. W. Evans; G. Gilmore; D. Just; S. Koposov; M. Mateo; E. Olszewski; L. Watkins; L. Wyrzykowski

    2010-01-01

    We report the discovery of two new Milky Way satellites in the neighboring constellations of Pisces and Pegasus identified in data from the Sloan Digital Sky Survey. Pisces II, an ultra-faint dwarf galaxy lies at the distance of ~180 kpc, some 15° away from the recently detected Pisces I. Segue 3, an ultra-faint star cluster lies at the distance of

  19. Infrared and Optical Observations of GRB 030115 and its Extremely Red Host Galaxy: Implications for Dark Bursts

    E-print Network

    Andrew Levan; Andrew Fruchter; James Rhoads; Bahram Mobasher; Nial Tanvir; Javier Gorosabel; Evert Rol; Chryssa Kouveliotou; Ian Dell'Antonio; Michael Merrill; Eddie Bergeron; José María Castro Cerón; Nicola Masetti; Paul Vreeswijk; Angelo Antonelli; David Bersier; Alberto Castro-Tirado; Johan Fynbo; Peter Garnavich; Stephen Holland; Jens Hjorth; Peter Nugent; Elena Pian; Alain Smette; Bjarne Thomsen; Stephen Thorsett; Ralph Wijers

    2006-08-08

    We present near-infrared (nIR) and optical observations of the afterglow of GRB 030115. Discovered in an infrared search at Kitt Peak 5 hours after the burst trigger, this afterglow is amongst the faintest observed in the R-band at an early epoch, and exhibits very red colors, with $R-K\\approx 6$. The magnitude of the optical afterglow of GRB 030115 is fainter than many upper limits for other bursts, suggesting that without early nIR observations it would have been classified as a ``dark'' burst. Both the color and optical magnitude of the afterglow are likely due to dust extinction and indicate that at least some optical afterglows are very faint due to dust along the line of sight. Multicolor {\\it Hubble Space Telescope} observations were also taken of the host galaxy and the surrounding field. Photometric redshifts imply that the host, and a substantial number of faint galaxies in the field are at $z \\sim 2.5$. The overdensity of galaxies is sufficiently great that GRB 030115 may have occurred in a rich high-redshift cluster. The host galaxy shows extremely red colors (R-K=5) and is the first GRB host to be classified as an Extremely Red Object (ERO). Some of the galaxies surrounding the host also show very red colors, while the majority of the cluster are much bluer, indicating ongoing unobscured star formation. As it is thought that much of high redshift star formation occurs in highly obscured environments it may be that GRB 030115 represent a transition object, between the relatively unobscured afterglows seen to date and a population which are very heavily extinguished, even in the nIR.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  1. Spectral Observations of Faint Markarian Galaxies of the Second Byurakan Survey. II

    E-print Network

    L. Carrasco; H. M. Tovmassian; J. A. Stepanian; V. H. Chavushyan; L. K. Erastova; J. R. Valdes

    1997-11-11

    We continue the program of spectroscopic observations of objects from the Second Byurakan Survey (SBS). This survey contains more than 1300 galaxies and 1700 star-like objects with m(pg)<19.5. Our work is aimed towards the construction of a complete sample of faint Markarian galaxies. Here, we present spectroscopic data for 43 galaxies. Amongst them six new Seyfert galaxies are found, namely two Sy 1 type (SBS 1343+544 and SBS 1433+500), one Sy 2 type (SBS 1620+545) and three likely Sy 2 type galaxies (SBS 1205+556, SBS 1344+527, SBS 1436+597). SBS 1343+544 falls into the luminosity gap between low-redshift QSOs and high luminosity Sefert galaxies. In the sample studied here, another 36 emission-line galaxies were spectroscopically confirmed. Thus far, 102 SBS galaxies brighter than m(pg)=17.5 have been observed with the Cananea 2.1m GHO telescope. The apparent magnitude and redshift distributions, the spectral classification, the relative intensities of emission lines, and other parameters, as well as slit spectra for all 43 observed galaxies are presented.

  2. Visual and Near-Infrared Photometry of Nearby Dwarf Spheroidals

    NASA Astrophysics Data System (ADS)

    Kerschbaum, F.; Nowotny, W.; Horn, J.; Schultheis, M.

    1999-01-01

    This paper is based on photometry from two different observational approaches. Both are of an explorative character and act as feasibility studies. First, results on broad-band photometry in Bessel V and I as well as narrow-band measurements in the Wing 778 nm and 812 nm filters of nearby dwarf spheroidals and galactic globular clusters using the new Austrian OEFOSC (OEsterreich Faint Object Spectrograph and Camera), a copy of the ESO Instrument EFOSC mounted on our 1.5-m telescope are presented. Whereas V and I are used as temperature indicators, Wing 778 nm and 812 nm measure TiO or CN band strengths in the case of O-rich or C-rich AGB stars, respectively. By such means these objects can be identified quite easily. By now we only have a few observations of some selected objects but for the future we plan long-term monitoring and follow up low-resolution spectroscopy of selected AGB stars. The second part of the contribution deals with the possibilities of using Gunn-I, J and KS measurements originating from the DENIS (DEep Near Infrared Survey of the southern sky) project on similar objects. A few southern dwarf spheroidals already observed within DENIS (covering now some 35% of the southern hemisphere) are selected. It turns out that with DENIS limiting magnitudes of about 18.5, 16.5, and 14.0 in I, J, and K, respectively, AGB stars situated in the most nearby galaxies like Sculptor, Sextans and Carina, with distance moduli between 19 and 20 are just within the limits of this survey. At such small distances, confusion because of the low resolution of DENIS plays a minor role, too.

  3. Infrared instrumentation for large telescopes: an alternative approach

    E-print Network

    E. Oliva

    1999-09-06

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

  4. An ISOCAM survey through gravitationally lensing galaxy clusters. IV. New results from mid-infrared observations of th e cluster Abell 2219

    E-print Network

    Coia, D; McBreen, B; Biviano, A; Smail, I; Altieri, B; Kneib, J P; McBreen, S; Sánchez-Fernández, C; O'Halloran, B

    2004-01-01

    The massive cluster of galaxies Abell 2219 (z = 0.228) was observed at 14.3 $\\mu$m with the Infrared Space Observatory and results were published by Barvainis et al. (1999). These observations have been reanalyzed using a method specifically designed for the detection of faint sources that had been applied to other clusters. Five new sources were detected and the resulting cumulative total of ten sources all have optical counterparts. The mid-infrared sources are identified with three cluster members, three foreground galaxies, an Extremely Red Object, a star and two galaxies of unknown redshift. The spectral energy distributions (SEDs) of the galaxies are fit with models from a selection, using the program GRASIL. Best-fits are obtained, in general, with models of galaxies with ongoing star formation. For three cluster members the infrared luminosities derived from the model SEDs are between ~5.7x10^10 Lsun and 1.4x10^11 Lsun, corresponding to infrared star formation rates between 10 and 24 Msun yr^-1. The t...

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

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanuka; Karmakar, Pradip

    2013-08-01

    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.

  6. Spitzer Detection of PAH and Silicate Dust Features in the Mid-Infrared Spectra of z~2 Ultraluminous Infrared Galaxies

    E-print Network

    Lin Yan; R. Chary; L. Armus; H. Teplitz; G. Helou; D. Frayer; D. Fadda; J. Surace; P. Choi

    2005-04-14

    We report the initial results from a Spitzer GO-1 program to obtain low resolution, mid-infrared spectra of infrared luminous galaxies at z~1-2. This paper presents the spectra of eight sources observed with the Spitzer InfraRed Spectrograph (IRS). Of the eight spectra, six have mid-IR spectral features, either emission from Polycyclic Aromatic Hydrocarbon (PAH) or silicate absorption. Based on these mid-IR features, the inferred six redshifts are in the range of 1.8-2.6. The remaining two spectra detect only strong continua, thus do not yield redshift information. Strong, multiple PAH emission features are detected in two sources, and weak PAH emission in another two. These data provide direct evidence that PAH molecules are present and directly observable in ULIRGs at z~2. The six sources with measured redshifts are dusty, infrared luminous galaxies at z~2 with estimated $L_{bol} \\sim 10^{13}L_\\odot$. Of the eight sources, two appear starburst dominated; two with only power law continua are probably type I QSOs; and the remaining four are likely composite systems containing a buried AGN and a starburst component. Since half of our sample are optically faint sources with R>25.5mag (Vega), our results demonstrate the potential of using mid-infrared spectroscopy, especially the Aromatic and silicate features produced by dust grains to directly probe optically faint and infrared luminous populations at high redshift.

  7. Infrared Thermometers

    NSDL National Science Digital Library

    John Schaefers

    2006-01-01

    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.

  8. Angular sizes and luminosity evolution of faint galaxies

    NASA Astrophysics Data System (ADS)

    Roche, N.; Ratnatunga, K.; Griffiths, R. E.; Im, M.; Neuschaefer, L.

    1996-10-01

    We investigate the number counts and the V-I colour, angular size and axis ratio distributions of 5384 faint galaxies detected with the refurbished Hubble Space Telescope (HST) Wide Field Planetary Camera, to limits of I~=25 on a 27-field strip and I~=26 on a single deeper field. These results are compared with non-evolving and pure luminosity evolution (PLE) models, with a steep (alpha=-1.65) luminosity function for late-type galaxies. In these models, we have aimed to incorporate surface brightness selection effects, which can produce a significant bias against detection of higher redshift galaxies with larger angular sizes. We find no deficit of large-angular-size galaxies relative to our non-evolving model. At I<~22 there is a significant (approximately factor of 2) excess of moderately large (0.4<=r_hl<=1.5 arcsec at 22<=I<=24) galaxies with blue (V-I<=1.2) colours over our non-evolving model. The observed angular size and colour distributions are reasonably well-fitted by our PLE model, when detection thresholds appropriate to the data are included. These results appear to provide positive evidence that L~L* galaxies do brighten significantly (by ~1 mag) to z~1-2, increasing the numbers of blue, large-angular-size, high-redshift galaxies seen at I<~22, and that L* evolution, in addition to a steep luminosity function, is needed to explain the steep galaxy number counts. We also investigate faint galaxy axis ratios. At 20<=I<=24 the smaller galaxies tended to be more rounded than galaxies of large angular size, suggesting that a greater proportion are ellipticals. On going faintward, however, the axis ratio distribution of the smaller galaxies appears to shift towards that of a spiral-dominated population, as expected if later-type galaxies have a much steeper luminosity function than ellipticals. The axis ratio distribution of larger-angular-size galaxies remains consistent with a spiral-dominated population over the whole 20<=I<=25 range, suggesting that most of the evolving high-redshift galaxies on these fields are spirals and that the high-redshift ellipticals are significantly dimmed by dust extinction.

  9. Beasts of the Southern Wild : Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds.

    NASA Astrophysics Data System (ADS)

    Koposov, Sergey E.; Belokurov, Vasily; Torrealba, Gabriel; Evans, N. Wyn

    2015-06-01

    We have used the publicly released Dark Energy Survey (DES) data to hunt for new satellites of the Milky Way (MW) in the southern hemisphere. Our search yielded a large number of promising candidates. In this paper, we announce the discovery of nine new unambiguous ultra-faint objects, whose authenticity can be established with the DES data alone. Based on the morphological properties, three of the new satellites are dwarf galaxies, one of which is located at the very outskirts of the MW, at a distance of 380 kpc. The remaining six objects have sizes and luminosities comparable to the Segue 1 satellite and cannot be classified straightforwardly without follow-up spectroscopic observations. The satellites we have discovered cluster around the LMC and the SMC. We show that such spatial distribution is unlikely under the assumption of isotropy, and, therefore, conclude that at least some of the new satellites must have been associated with the Magellanic Clouds in the past.

  10. The First Hyper-luminous Infrared Galaxy Discovered by WISE

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  11. The First Hyper-Luminous Infrared Galaxy Discovered by WISE

    NASA Technical Reports Server (NTRS)

    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

    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.

  12. Assessing the AGN Component in the Faint Radio Population

    NASA Astrophysics Data System (ADS)

    Prandoni, Isabella; Ricci, Roberto; Parma, Paola; de Ruiter, Hans

    2011-04-01

    The radio/optical analysis of a sample of 26 faint radio sources extracted from the ATESP survey has revealed a class of compact flat/inverted radio sources associated with early-type galaxies up to redshift 2. Possible explanations invoke a) low radiative efficiency accretion (ADAF) models, possibly co-existing with outflows or jets; b) young radio sources (GPS-like); c) obscured radio-quiet quasars. A multi-frequency (6, 3 and 1.2 cm) ATCA campaign in 2007-2008 helped us to shed light on the accretion mechanism. Most source spectra appear to be consistent with those of either jet-dominated or ADAF+jet systems. Among the flat/inverted sources we could also have a component of unresolved radio-quiet quasars. Here we ask to extend the previous observations to higher frequency bands (7 and 3 mm) in order to better characterize the mm behaviour of the radio spectrum and improve our understanding of the relative contribution of radio jets and ADAF mechanism in presence of a steepening radio spectrum. Separate high resolution observations at 40 GHz are asked to discriminate between jet-dominated radio galaxies and truly compact quasar-like sources.

  13. Luminosity Function of Faint Globular Clusters in M87

    E-print Network

    Christopher Z. Waters; Stephen E. Zepf; Tod R. Lauer; Edward A. Baltz; Joseph Silk

    2006-07-11

    We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit \\textit{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.

  14. Helium shells and faint emission lines from slitless flash spectra.

    PubMed

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    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

  15. Carbon Dioxide Cycling, Climate, Impacts, and the Faint Young Sun

    NASA Technical Reports Server (NTRS)

    Zahnle, K. J.; Sleep, H. H.

    1999-01-01

    Evidence for relatively mild climates on ancient Earth and Mars has been a puzzle in light of the faint early sun. The geologic evidence, although far from conclusive, would appear to indicate that the surfaces of both planets were, if anything, warmer ca. 3-4 Ga than they are now. The astrophysical argument that the sun ought to have brightened approx. 30% since it reached the main sequence is hard to refute. There results a paradox between the icehouse we expect and the greenhouse we think we see. The usual fix has been to posit massive CO2 atmospheres, although reduced gases (e.g., NH3 or CH4 ) have had their partisans. Evidence against siderite in paleosols dated 2.2-2.75 Ga sets a rough upper limit of 30 PAL (present atmospheric levels) on pCO2 at that time. This is an order of magnitude short of what is needed to defeat the fainter sun. We present here an independent argument against high pCO2 on early Earth that applies not only to the Archean but yet more forcefully to the Hadean era. Additional information is contained in the original extended abstract.

  16. Radio faint AGN: a tale of two populations

    E-print Network

    Padovani, P; Kellermann, K I; Miller, N; Mainieri, V; Tozzi, P

    2015-01-01

    We study the Extended Chandra Deep Field South (E-CDFS) Very Large Array sample, which reaches a flux density limit at 1.4 GHz of 32.5 microJy at the field centre and redshift ~ 4, and covers ~ 0.3 deg^2. Number counts are presented for the whole sample while the evolutionary properties and luminosity functions are derived for active galactic nuclei (AGN). The faint radio sky contains two totally distinct AGN populations, characterised by very different evolutions, luminosity functions, and Eddington ratios: radio-quiet (RQ)/radiative-mode, and radio-loud/jet-mode AGN. The radio power of RQ AGN evolves ~ (1+z)^2.5, similarly to star-forming galaxies, while the number density of radio-loud ones has a peak at ~ 0.5 and then declines at higher redshifts. The number density of radio-selected RQ AGN is consistent with that of X-ray selected AGN, which shows that we are sampling the same population. The unbiased fraction of radiative-mode RL AGN, derived from our own and previously published data, is a strong funct...

  17. Luminosity Function of Faint Globular Clusters in M87

    NASA Astrophysics Data System (ADS)

    Waters, Christopher Z.; Zepf, Stephen E.; Lauer, Tod R.; Baltz, Edward A.; Silk, Joseph

    2006-10-01

    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.

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

    E-print Network

    To, Chun-Hao; Owen, Frazer N

    2014-01-01

    We present a statistical detection of 1.5 GHz radio continuum emission from a sample of faint z~4 Lyman-break galaxies (LBGs). LBGs are key tracers of the high-redshift star formation history and important sources of UV photons that ionized the intergalactic medium in the early universe. In order to better constrain the extinction and intrinsic star formation rate (SFR) of high-redshift LBGs, we combine the latest ultradeep Karl G. Jansky Very Large Array 1.5 GHz radio image and the Hubble Space Telescope Advance Camera for Surveys (ACS) optical images in the Great Observatories Origins Deep Survey-North. We select a large sample of 1771 z~4 LBGs from the ACS catalogue using $\\bband$-dropout color criteria. Our LBG samples have $\\iband$~25-28 (AB), ~0-3 magnitudes fainter than M*_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 ...

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  20. The near-infrared counterpart of a variable galactic plane radio source

    NASA Technical Reports Server (NTRS)

    Margon, Bruce; Phillips, Andrew C.; Ciardullo, Robin; Jacoby, George H.

    1992-01-01

    A near-infrared counterpart to the highly variable, unresolved galactic plane radio source GT 0116 + 622 is identified. This source is of particular interest, as it has been previously suggested to be the counterpart of the gamma-ray source Cas gamma-l. The present NIR and red images detect a faint, spatially extended (3 arcsec FWHM), very red object coincident with the radio position. There is complex spatial structure which may be due in part to an unrelated superposed foreground object. Observations on multiple nights show no evidence for flux variability, despite the high amplitude variability on a time-scale of days reported for the radio source. The data are consistent with an interpretation of GT 0116 + 622 as an unusually variable, obscured active galaxy at a distance of several hundred megaparsecs, although more exotic, and in particular galactic, interpretations cannot yet be ruled out. If the object is extragalactic, the previously suggested identification with the gamma-ray source would seem unlikely.

  1. NASA Researches the 'FaINT' Side of Sonic Booms - Duration: 2 minutes, 24 seconds.

    NASA Video Gallery

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

  2. Infrared and Optical Observations of GRB 030115 and its ExtremelyRed Host Galaxy: Implications for Dark Bursts

    SciTech Connect

    Levan, Andrew; Fruchter, Andrew; Rhoads, James; Mobasher, Bahram; Tanvir, Nial; Gorosabel, Javier; Rol, Evert; Kouveliotou, Chryssa; Dell'Antonio, Ian; Merrill, Michael; Bergeron, Eddie; Castro Ceron, JosMar a; Masetti, Nicola; Vreeswijk, Paul; Antonelli, Angelo; Bersier,David; Castro-Tirado, Alberto; Fynbo, Johan; Garnavich, Peter; Holland,Stephen; Hjorth, Jens; Nugent, Peter; Pian, Elena; Smette, Alain; Thomsen, Bjarne; Thorsett, Stephen E.; Wijers, Ralph

    2006-05-01

    We present near-infrared (NIR) and optical observations ofthe afterglow of GRB 030115. Discovered in aninfrared search at Kitt Peak5 hr after the burst trigger, this afterglow is the faintest everobserved in the R band at such an early epoch and exhibits very redcolors, with R-K~;6. The optical magnitude of the afterglow of GRB 030115is fainter than many upper limits for other bursts, suggesting thatwithout early NIR observations it would have been classified as a "dark"burst. Both the color and optical magnitude of the afterglow are likelydue to dust extinction atmoderate redshift z>2 and indicate that atleast some optical afterglows are very faint due to dust along the lineof sight.Multicolor Hubble Space Telescope observations were also takenof the host galaxy and the surrounding field. Photometric redshifts implythat the host and a substantial number of faint galaxies in the field areat z 2:5. The overdensity of galaxies is sufficiently great that GRB030115 may have occurred in a rich high-redshift cluster. The host galaxyshows extremely red colors (R-K = 5) and is the first GRB host to beclassified as an extremely red object (ERO). Some of the galaxiessurrounding the host also show very red colors, while the majority of theclusterare much bluer, indicating ongoing unobscured star formation. Asit is thought that much of high-redshift starformation occurs in highlyobscured environments, it may well be that GRB 030115 represents atransition object, between the relatively unobscured afterglows seen todate and a population of objects that are very heavily extinguished, evenin the NIR.

  3. High energy gamma-emission of faint solar flares

    NASA Astrophysics Data System (ADS)

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

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

  4. Signs of a faint disc population at polluted white dwarfs

    E-print Network

    Bergfors, Carolina; Dufour, Patrick; Rocchetto, Marco

    2014-01-01

    Observations of atmospheric metals and dust discs around white dwarfs provide important clues to the fate of terrestrial planetary systems around intermediate mass stars. We present Spitzer IRAC observations of 15 metal polluted white dwarfs to investigate the occurrence and physical properties of circumstellar dust created by the disruption of planetary bodies. We find subtle infrared excess emission consistent with warm dust around KUV 15519+1730 and HS 2132+0941, and weaker excess around the DZ white dwarf G245-58, which, if real, makes it the coolest white dwarf known to exhibit a 3.6 micron excess and the first DZ star with a bright disc. All together our data corroborate a picture where 1) discs at metal-enriched white dwarfs are commonplace and most escape detection in the infrared (possibly as narrow rings), 2) the discs are long lived, having lifetimes on the order of 10^6 yr or longer, and 3) the frequency of bright, infrared detectable discs decreases with age, on a timescale of roughly 500 Myr, su...

  5. EROs found behind lensing clusters. I. Stellar populations and dust properties of optical dropout EROs and comparison with related objects

    Microsoft Academic Search

    D. Schaerer; A. Hempel; E. Egami; R. Pelló; J. Richard; J.-F. Le Borgne; J.-P. Kneib; M. Wise; F. Boone

    2007-01-01

    Context: On the nature, redshift, stellar populations and dust properties of optically faint or non-detected extremely red objects. Aims: Determining the nature, redshift, stellar populations and dust properties of optically faint or non-detected, extremely red objects (ERO) found from our survey of the lensing clusters A1835 and AC114 (Richard et al. 2006, A&A, 456, 861). Comparison with properties of related

  6. Discovery of Jets and HH-like Objects near the S255 IR Complex

    NASA Astrophysics Data System (ADS)

    Miralles, Mari Paz; Salas, Luis; Cruz-González, Irene; Kurtz, Stan

    1997-10-01

    We report the discovery of two jets and eight HH-like objects in molecular hydrogen near the Sharpless H II region S255 and present near-infrared observations of these objects. The field has been imaged in [Fe II] (1.644 ?m), cK (2.26 ?m), H2 v = 1 --> 0 S(1), and H2 v = 2 --> 1 S(1), as well as in broadband JHK' filters, as part of an ongoing near-infrared survey of massive star-forming regions. These observations reveal in detail the morphology of low and intermediate-velocity shocks in the region. The HH-like objects are seen only in H2. The brightest H2 clump is found to the southwest of the S255 IR complex. We see evidence of one possible counterjet: a faint H2 tail to the northeast of S255 IR, seen as a series of clumps. Their arc-shaped geometry is indicative of bow shocks. Diffuse emission is also seen in S255 IR, toward the north and south. K-band long-slit spectroscopy suggests a collisional nature for the brightest H2 object rather than fluorescence. These observations also indicate that the Br? excess present in S255 IR may be produced by the stellar wind of the very red star NIRS 1, while the H2 diffuse emission may come from collisionally shocked gas present in the extended nebulosity of the region. We also present the results of 12CO (J = 1 --> 0) observations of the region. We find two foci of accelerated molecular gas, which suggests the presence of two molecular outflows, one associated with the ultracompact H II region G192.58-0.04 and the other with the S255 IR region and one of the jets.

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

    NASA Technical Reports Server (NTRS)

    Treyer, Marie-Agnes; Silk, Joseph

    1993-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

  9. Far-infrared polarimetry

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger H.; Dotson, Jesse L.; Dowell, C. Darren; Platt, S. R.; Schleuning, David; Davidson, J. A.; Novak, Giles

    1995-01-01

    Airborne observations with the The University of Chicago polarimeter, Stokes (Platt et al. 1991), have produced maps of far infrared polarization over large areas in molecular clouds. Subsequent papers will discuss the implications of the results concerning the magnetic fields of individual objects. Our purpose here is to show a broad sample of the results and to point out certain general characteristics of the polarized emission.

  10. THE AROMATIC FEATURES IN VERY FAINT DWARF GALAXIES

    SciTech Connect

    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

    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.

  11. Time series photometry of faint cataclysmic variables with a CCD

    NASA Astrophysics Data System (ADS)

    Abbott, Timothy Mark Cameron

    1992-08-01

    I describe a new hardware and software environment for the practice of time-series stellar photometry with the CCD systems available at McDonald Observatory. This instrument runs suitable CCD's in frame transfer mode and permits windowing on the CCD image to maximize the duty cycle of the photometer. Light curves may be extracted and analyzed in real time at the telescope and image data are stored for later, more thorough analysis. I describe a star tracking algorithm, which is optimized for a timeseries of images of the same stellar field. I explore the extraction of stellar brightness measures from these images using circular software apertures and develop a complete description of the noise properties of this technique. I show that scintillation and pixelization noise have a significant effect on high quality observations. I demonstrate that optimal sampling and profile fitting techniques are unnecessarily complex or detrimental methods of obtaining stellar brightness measures under conditions commonly encountered in timeseries CCD photometry. I compare CCD's and photomultiplier tubes as detectors for timeseries photometry using light curves of a variety of stars obtained simultaneously with both detectors and under equivalent conditions. A CCD can produce useful data under conditions when a photomultiplier tube cannot, and a CCD will often produce more reliable results even under photometric conditions. I prevent studies of the cataclysmic variables (CV's) AL Com, CP Eri, V Per, and DO Leo made using the time series CCD photometer. AL Com is a very faint CV at high Galactic latitude and a bona fide Population II CV. Some of the properties of AL Com are similar to the dwarf nova WZ Sge and others are similar to the intermediate polar EX Hya, but overall AL Com is unlike any other well-studied cataclysmic variable. CP Eri is shown to be the fifth known interacting binary white dwarf. V Per was the first CV found to have an orbital period near the middle of the gap in the orbital period distribution of CV's. DO Leo is an eclipsing CV which can reasonably be included in a sample of Population II CV candidates.

  12. Infrared Thermometer

    NASA Technical Reports Server (NTRS)

    1991-01-01

    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.

  13. Lines and continuum sky emission in the near infrared: observational constraints from deep high spectral resolution spectra with GIANO-TNG

    E-print Network

    Oliva, E; Scuderi, S; Benatti, S; Carleo, I; Lapenna, E; Mucciarelli, A; Baffa, C; Biliotti, V; Carbonaro, L; Falcini, G; Giani, E; Iuzzolino, M; Massi, F; Sanna, N; Sozzi, M; Tozzi, A; Ghedina, A; Ghinassi, F; Lodi, M; Harutyunyan, A; Pedani, M

    2015-01-01

    Aims Determining the intensity of lines and continuum airglow emission in the H-band is important for the design of faint-object infrared spectrographs. Existing spectra at low/medium resolution cannot disentangle the true sky-continuum from instrumental effects (e.g. diffuse light in the wings of strong lines). We aim to obtain, for the first time, a high resolution infrared spectrum deep enough to set significant constraints on the continuum emission between the lines in the H-band. Methods During the second commissioning run of the GIANO high-resolution infrared spectrograph at La Palma Observatory, we pointed the instrument directly to the sky and obtained a deep spectrum that extends from 0.97 to 2.4 micron. Results The spectrum shows about 1500 emission lines, a factor of two more than in previous works. Of these, 80% are identified as OH transitions; half of these are from highly excited molecules (hot-OH component) that are not included in the OH airglow emission models normally used for astronomical ...

  14. THE WFC3 INFRARED SPECTROSCOPIC PARALLEL (WISP) SURVEY

    SciTech Connect

    Atek, H.; Scarlata, C.; Colbert, J. W.; Shim, H. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Malkan, M.; Ross, N. R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90024 (United States); McCarthy, P.; Dressler, A. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Teplitz, H. I. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Siana, B.; Bridge, C. [Department of Astronomy, Caltech, Pasadena, CA 91125 (United States); Henry, A.; Martin, C. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Bunker, A. J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, OX13RH (United Kingdom); Fosbury, R. A. E. [Space Telescope-European Coordinating Facility, Garching (Germany)

    2010-11-01

    We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of {approx}90 independent, high-latitude fields by observing in the pure-parallel mode with the Wide Field Camera Three on the Hubble Space Telescope for a total of {approx}250 orbits. Spectra are obtained with the G{sub 102} ({lambda} = 0.8-1.17 {mu}m, R {approx}210) and G{sub 141} grisms ({lambda} = 1.11-1.67 {mu}m, R {approx}130), together with direct imaging in the J and H bands (F110W and F140W, respectively). In the present paper, we present the first results from 19 WISP fields, covering approximately 63 arcmin{sup 2}. For typical exposure times ({approx}6400 s in G{sub 102} and {approx}2700 s in G{sub 141}), we reach 5{sigma} detection limits for emission lines of f {approx} 5 x 10{sup -17} erg s{sup -1} cm{sup -2} for compact objects. Typical direct imaging 5{sigma} limits are 26.3 and 26.1 mag. (AB) in F110W and F140W, respectively. Restricting ourselves to the lines measured with the highest confidence, we present a list of 328 emission lines, in 229 objects, in a redshift range 0.3 < z < 3. The single-line emitters are likely to be a mix of H{alpha} and [O III]5007,4959 A, with H{alpha} predominating. The overall surface density of high-confidence emission-line objects in our sample is approximately 4 per arcmin{sup 2}. These first fields show high equivalent width sources, active galactic nucleus, and post-starburst galaxies. The median observed star formation rate (SFR) of our H{alpha}-selected sample is 4 M{sub sun} yr{sup -1}. At intermediate redshifts, we detect emission lines in galaxies as faint as H{sub 140} {approx} 25, or M{sub R} < -19, and are sensitive to SFRs down to less than 1 M{sub sun} yr{sup -1}. The slitless grisms on WFC3 provide a unique opportunity to study the spectral properties of galaxies much fainter than L* at the peak of the galaxy assembly epoch.

  15. On the nature of faint low surface brightness galaxies in the Coma cluster

    NASA Astrophysics Data System (ADS)

    Adami, C.; Pelló, R.; Ulmer, M. P.; Cuillandre, J. C.; Durret, F.; Mazure, A.; Picat, J. P.; Scheidegger, R.

    2009-02-01

    Context: This project is the continuation of our study of faint Low Surface Brightness Galaxies (fLSBs) in one of the densest nearby (z = 0.023) galaxy regions known, the Coma cluster. Aims: Our goal is to improve our understanding of the nature of these objects by comparing the broad band spectral energy distribution with population synthesis models, in order to infer ages, dust extinction and spectral characteristics. Methods: The data were obtained with the MEGACAM and CFH12K cameras at the CFHT. We used the resulting photometry in 5 broad band filters (u*, B, V, R, and I) that included new u*-band data to fit spectral models. With these spectral fits we inferred a cluster membership criterium, as well as the ages, dust extinctions, and photometric types of these fLSBs. Results: We show that about half of the Coma cluster fLSBs have a spectral energy distribution well represented in our template library (best fit fLSBs, BF) while the other half present a flux deficit at ultraviolet wavelengths (moderately good fit fLSBs, MGF). Among the BF fLSBs, ~80% are probably part of the Coma cluster based on their spectral energy distribution. BF fLSBs are relatively young (younger than 2.3 Gyr for 90% of the sample) non-starburst objects. The later their type, the younger the fLSBs are. A significant part of the BF fLSBs are quite dusty objects (1/3 have AV greater than 1.5). BF fLSBs are low stellar mass objects (the later their type the less massive they are), with stellar masses comparable to globular clusters for the faintest ones. Their characteristics are partly correlated with infall directions, confirming the disruptive origin for at least part of them. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (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.

  16. COOL WHITE DWARFS FOUND IN THE UKIRT INFRARED DEEP SKY SURVEY

    SciTech Connect

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

    2011-07-01

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

  17. Infrared Thermometers

    ERIC Educational Resources Information Center

    Schaefers, John

    2006-01-01

    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…

  18. Infrared Spectroscopy

    NSDL National Science Digital Library

    C. P. Sherman Hsu

    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.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  20. Hubble Provides Infrared View of Jupiter's Moon, Ring, and Clouds

    NASA Technical Reports Server (NTRS)

    1997-01-01

    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/

  1. Improving the Visible and Infrared Contrast Ratio of Microshutter Arrays

    NASA Technical Reports Server (NTRS)

    Jhabvala, Murzy; Li, Mary; Moseley, Harvey; Franz, Dave; Yun, Zheng; Kutyrev, Alexander

    2009-01-01

    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.

  2. Detection of a Faint Fast-moving Near-Earth Asteroid Using the Synthetic Tracking Technique

    NASA Astrophysics Data System (ADS)

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit; Hallinan, Gregg; Harding, Leon K.

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day-1 and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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 ?.

  4. FAINT POPULATION III SUPERNOVAE AS THE ORIGIN OF THE MOST IRON-POOR STARS

    SciTech Connect

    Ishigaki, Miho N.; Tominaga, Nozomu; Kobayashi, Chiaki; Nomoto, Ken'ichi, E-mail: miho.ishigaki@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2014-09-10

    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 {sub 51} = E/10{sup 51} erg =1) and hypernovae (E {sub 51} ? 10) of Population III 25 M {sub ?} or 40 M {sub ?} 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 {sup 56}Ni less than 10{sup –3} M {sub ?}.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  6. Infrared floodlight

    DOEpatents

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

    1986-08-05

    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.

  7. Method for imaging a concealed object

    DOEpatents

    Davidson, James R [Idaho Falls, ID; Partin, Judy K [Idaho Falls, ID; Sawyers, Robert J [Idaho Falls, ID

    2007-07-03

    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.

  8. An ISOCAM survey through gravitationally lensing galaxy clusters. III. New results from mid-infrared observations of the cluster Abell 2219

    NASA Astrophysics Data System (ADS)

    Coia, D.; Metcalfe, L.; McBreen, B.; Biviano, A.; Smail, I.; Altieri, B.; Kneib, J.-P.; McBreen, S.; Sanchez-Fernandez, C.; O'Halloran, B.

    2005-01-01

    The massive cluster of galaxies Abell 2219 (z = 0.228) with two spectacular gravitational lensing arcs was observed at 14.3 ?m (hereafter 15 ?m) with the Infrared Space Observatory and results were published by Barvainis et al. (\\cite{1999AJ....118..645B}). These observations have been reanalyzed using a method specifically designed for the detection of faint sources that had been applied to other clusters. Five new sources were detected and the resulting cumulative total of ten sources all have optical counterparts. The mid-infrared sources are identified with three cluster members, three foreground galaxies, an Extremely Red Object, a star and two galaxies of unknown redshift. The spectral energy distributions (SEDs) of the galaxies are fit with models from a selection, using the program GRASIL. Best-fits are obtained, in general, with models of galaxies with ongoing star formation. Infrared luminosities and star formation rates are obtained for six sources: the cluster members and the foreground galaxies. For the three cluster members the infrared luminosities derived from the model SEDs are between ˜5.7 × 1010 L? and 1.4 × 1011 L?, corresponding to infrared star formation rates between 10 and 24 M? yr-1. The two cluster galaxies that have optical classifications are in the Butcher-Oemler region of the color-magnitude diagramme. The three foreground galaxies have infrared luminosities between 1.5 × 1010 L? and 9.4 × 1010 L? yielding infrared star formation rates between 3 and 16 M? yr-1. Two of the foreground galaxies are located in two foreground galaxy enhancements (Boschin et al. \\cite{2004A&A...416..839B}). Including Abell 2219, six distant clusters of galaxies have been mapped with ISOCAM and luminous infrared galaxies (LIRGs) have been found in three of them. The presence of LIRGs in Abell 2219 strengthens the association between luminous infrared galaxies in clusters and recent or ongoing cluster merger activity. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the UK) and with the participation of ISAS and NASA.

  9. Big Fish, Little Fish: Two New Ultra-faint Satellites of the Milky Way

    NASA Astrophysics Data System (ADS)

    Belokurov, V.; Walker, M. G.; Evans, N. W.; Gilmore, G.; Irwin, M. J.; Just, D.; Koposov, S.; Mateo, M.; Olszewski, E.; Watkins, L.; Wyrzykowski, L.

    2010-03-01

    We report the discovery of two new Milky Way satellites in the neighboring constellations of Pisces and Pegasus identified in data from the Sloan Digital Sky Survey. Pisces II, an ultra-faint dwarf galaxy lies at the distance of ~180 kpc, some 15° away from the recently detected Pisces I. Segue 3, an ultra-faint star cluster lies at the distance of 16 kpc. We use deep follow-up imaging obtained with the 4-m Mayall Telescope at Kitt Peak National Observatory to derive their structural parameters. Pisces II has a half-light radius of ~60 pc, while Segue 3 is 20 times smaller at only 3 pc.

  10. The SCUBA HAlf Degree Extragalactic Survey (SHADES) - V. Submillimetre properties of near-infrared-selected galaxies in the Subaru/XMM -Newton deep field

    NASA Astrophysics Data System (ADS)

    Takagi, T.; Mortier, A. M. J.; Shimasaku, K.; Coppin, K.; Pope, A.; Ivison, R. J.; Hanami, H.; Serjeant, S.; Clements, D. L.; Priddey, R. S.; Dunlop, J. S.; Takata, T.; Aretxaga, I.; Chapman, S. C.; Eales, S. A.; Farrah, D.; Granato, G. L.; Halpern, M.; Hughes, D. H.; van Kampen, E.; Scott, D.; Sekiguchi, K.; Smail, I.; Vaccari, M.

    2007-11-01

    We have studied the submillimetre (submm) properties of the following classes of near-infrared-selected (NIR-selected) massive galaxies at high redshifts: BzK-selected star-forming galaxies (BzKs); distant red galaxies (DRGs); and extremely red objects (EROs). We used the SCUBA HAlf Degree Extragalactic Survey (SHADES), the largest uniform submm survey to date. Partial overlap of SIRIUS/NIR images and SHADES in Subaru/XMM-Newton deep field has allowed us to identify four submm-bright NIR-selected galaxies, which are detected in the mid-IR, 24? m, and the radio, 1.4GHz. We find that all of our submm-bright NIR-selected galaxies satisfy the BzK selection criteria, i.e. BzK ? (z - K)AB - (B - z)AB >= -0.2, except for one galaxy whose B - z and z - K colours are however close to the BzK colour boundary. Two of the submm-bright NIR-selected galaxies satisfy all of the selection criteria we considered, i.e. they belong to the BzK-DRG-ERO overlapping population, or `extremely red' BzKs. Although these extremely red BzKs are rare (0.25 arcmin-2), up to 20 per cent of this population could be submm galaxies. This fraction is significantly higher than that found for other galaxy populations studied here. Via a stacking analysis, we have detected the 850-? m flux of submm-faint BzKs and EROs in our SCUBA maps. While the contribution of z ~ 2 BzKs to the submm background is about 10-15 per cent and similar to that from EROs typically at z ~ 1, BzKs have a higher fraction (~30 per cent) of submm flux in resolved sources compared with EROs and submm sources as a whole. From the spectral energy distribution (SED) fitting analysis for both submm-bright and submm-faint BzKs, we found no clear signature that submm-bright BzKs are experiencing a specifically luminous evolutionary phase, compared with submm-faint BzKs. An alternative explanation might be that submm-bright BzKs are more massive than submm-faint ones.

  11. Cool Cosmos: Infrared Astronomy Tutorial

    NSDL National Science Digital Library

    NASA IPAC/CALTECH

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

  12. THE CALIBRATION OF MONOCHROMATIC FAR-INFRARED STAR FORMATION RATE INDICATORS

    SciTech Connect

    Calzetti, D.; Wu, S.-Y.; Hong, S. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Kennicutt, R. C.; Hao, C.-N.; Begum, A.; Johnson, B. [Institute of Astronomy, Cambridge University, Cambridge (United Kingdom); Lee, J. C. [Carnegie Observatories of Washington, Pasadena, CA (United States); Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, WY (United States); Engelbracht, C. W.; Block, M. [Steward Observatory, University of Arizona, AZ (United States); Van Zee, L. [Department of Astronomy, University of Indiana, IN (United States); Draine, B. T. [Princeton University Observatory, Peyton Hall, Princeton, NJ (United States); Gordon, K. D.; Regan, M. [Space Telescope Science Institute, Baltimore, MD (United States); Moustakas, J. [Center for Astrophysics and Space Sciences, University of California, San Diego, CA (United States); Murphy, E. J. [Spitzer Science Center, Caltech, CA (United States); Dalcanton, J. [Department of Astronomy, University of Washington, WA (United States); Funes, J. [Vatican Observatory, University of Arizona, AZ (United States); Gil de Paz, A., E-mail: calzetti@astro.umass.ed [Departamento de Astrofisica, Universidad Computense de Madrid (Spain)

    2010-05-10

    Spitzer data at 24, 70, and 160 {mu}m and ground-based H{alpha} images are analyzed for a sample of 189 nearby star-forming and starburst galaxies to investigate whether reliable star formation rate (SFR) indicators can be defined using the monochromatic infrared dust emission centered at 70 and 160 {mu}m. We compare recently published recipes for SFR measures using combinations of the 24 {mu}m and observed H{alpha} luminosities with those using 24 {mu}m luminosity alone. From these comparisons, we derive a reference SFR indicator for use in our analysis. Linear correlations between SFR and the 70 {mu}m and 160 {mu}m luminosity are found for L(70) {approx_gt} 1.4 x 10{sup 42} erg s{sup -1} and L(160) {approx_gt} 2 x 10{sup 42} erg s{sup -1}, corresponding to SFR {approx_gt} 0.1-0.3 M{sub sun} yr{sup -1}, and calibrations of SFRs based on L(70) and L(160) are proposed. Below those two luminosity limits, the relation between SFR and 70 {mu}m (160 {mu}m) luminosity is nonlinear and SFR calibrations become problematic. A more important limitation is the dispersion of the data around the mean trend, which increases for increasing wavelength. The scatter of the 70 {mu}m (160 {mu}m) data around the mean is about 25% (factor {approx}2) larger than the scatter of the 24 {mu}m data. We interpret this increasing dispersion as an effect of the increasing contribution to the infrared emission of dust heated by stellar populations not associated with the current star formation. Thus, the 70 (160) {mu}m luminosity can be reliably used to trace SFRs in large galaxy samples, but will be of limited utility for individual objects, with the exception of infrared-dominated galaxies. The nonlinear relation between SFR and the 70 and 160 {mu}m emission at faint galaxy luminosities suggests a variety of mechanisms affecting the infrared emission for decreasing luminosity, such as increasing transparency of the interstellar medium, decreasing effective dust temperature, and decreasing filling factor of star-forming regions across the galaxy. In all cases, the calibrations hold for galaxies with oxygen abundance higher than roughly 12 +log(O/H) {approx} 8.1. At lower metallicity, the infrared luminosity no longer reliably traces the SFR because galaxies are less dusty and more transparent.

  13. Infrared upconversion hyperspectral imaging.

    PubMed

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

    2015-03-15

    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

  14. Study on the faint star extraction technology with MEMS gyro aided APS star tracker

    NASA Astrophysics Data System (ADS)

    Xing, Fei; Zhao, Borui; Sun, Ting; Xu, Wei; You, Zheng

    2013-08-01

    Star tracker is the most accurate attitude sensor for satellite. Generally speaking, the higher the accuracy, the fainter the star can be sensed by the star tracker. How to extract the faint star from a star image is becoming a critical technology in dynamic condition for star tracker, especially using the APS (Active Pixels Sensor) detector. A novel APS star tracker with MEMS Gyroscope aided system was proposed in this paper that could extremely improve the detection effect and capability for the faint stars. During the exposure time of star tracker, the trajectory of star projection on the detector maybe occupy more than ten pixels due to the satellite rotation. In this situation, the signal-to-noise ratio will decline sharply, and the traditional star extraction method for faint star will take no effect. As a result, the accuracy of star tracker would decline sharply, even more, couldn't work. Using the MEMS Gyroscope, the track of star projection can be predicated and measured, on the basis of which the deconvolution algorithm could be taken to recover the faint star signal. The accuracy of the star projection centroid could be improved obviously, and the dynamic performance of the star tracker would be improved by a magnitude. Meanwhile, the MEMS gyroscope has not less volume, mass and power consumption, which make it more suitable for the application of APS star tracker.

  15. An infrared companion to Z Canis Majoris

    NASA Technical Reports Server (NTRS)

    Koresko, Chris D.; Beckwith, Steven V. W.; Ghez, Andrea M.; Matthews, Keith; Neugebauer, Gerry

    1991-01-01

    New near-infrared speckle observations of Z CMa reveal it to be a double star with a separation 0.1 arcsec at P.A. 120 deg. The northwest component is an infrared object whose broadband spectrum is reminiscent of the infrared companions to several T Tauri stars. The southeast component has the spectral energy distribution expected for a circumstellar disk whose luminosity is dominated by gravitational accretion. The far-infrared and millimeter-wave photometric fluxes suggest the presence of a massive second disk large enough to surround both components; this may be the reservoir from which the material accreted by the first disk is drawn.

  16. Feedback & Objectives

    ERIC Educational Resources Information Center

    Butterworth, James R.

    1975-01-01

    Industrial objectives, if they are employee oriented, produce feedback, and the motivation derived from the feedback helps reduce turnover. Feedback is the power to clarify objectives, to stimulate communication, and to motivate people. (Author/MW)

  17. Real Time Pedestrian Tracking using Thermal Infrared Imagery

    E-print Network

    Del Moral , Pierre

    model. In infrared images, the surrounding's non-pedestrian target objects' (such as cars, animals imagery. It makes use of the characteristics of pedestrian body regions in infrared images, which is based automatically. The experimental results are gained by using different infrared image sequences, which show

  18. Calibration of Aerial Thermal Infrared Imagery for Walrus Population Assessment

    Microsoft Academic Search

    DAVID G. BARBER; PIERRE R. RICHARD; KLAUS P. HOCHHEIM; JACK ORR

    1991-01-01

    Concurrent aerial photography and emitted thermal infrared (10.6 imagery were acquired over walrus hauled out on sea ice in Foxe Basin, Northwest Territories, Canada. Digital thermal infrared data from a Forward Looking Infrared (FLIR) imager provides a method for estimating walrus numbers, since the objects (walrus groups) are considerably warmer than the background (ocean and sea ice). Coincident photographic counts

  19. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  20. Infrared Imaging Surveyor (IRIS) project

    NASA Astrophysics Data System (ADS)

    Shibai, Hiroshi; Murakami, Hiroshi

    1996-06-01

    In this paper we describe the concept and the design of the InfraRed Imaging Surveyor (IRIS), the first Japanese satellite solely dedicated to infrared astronomy. It will follow a successful precursor, the Infrared Telescope in Space (IRTS) onboard the Space Flyer Et (SFU) in 1995. The IRIS has a 70 cm telescope cooled down to 7 K by using superfluid helium assisted by two-state Stirling cycle coolers. The expected hold time of the super-fluid helium is one year. After consumption of the helium, near-infrared observation can be continued by using the mechanical coolers. Two focal plane instruments are planned; the infrared camera (IRC) and the far-infrared surveyor (FIS). The total spectral coverage is 2 to 200 microns. The major scientific objectives are to investigate birth and evolution of galaxies in the early universe by survey of young normal galaxies and starburst galaxies. The orbit is a sun- synchronous orbit, in which the cooled telescope can avoid huge emissions from the Sun and the Earth by pointing the telescope on the great circle perpendicular to the Sun. The IRIS project is expected to start in 1997 and it will be launched by a M-V rocket in 2002.

  1. Imaging single living cells with a scanning near-eld infrared microscope based on a free electron laser

    E-print Network

    Dokholyan, Nikolay V.

    . Infrared microspec- trometers coupled to infrared focal plane array detectors allow for parallel to refractive objectives, but have the advantage that the focal length is the same throughout the infrared

  2. Far infrared and submillimetre surveys: from IRAS to Akari, Herschel and Planck

    E-print Network

    Rowan-Robinson, Michael

    2015-01-01

    We discuss a new IRAS Faint Source Catalog galaxy redshift catalogue (RIFSCz) which incorporates data from Galex, SDSS, 2MASS, WISE, Akari and Planck. Akari fluxes are consistent with photometry from other far infrared and submillimetre missions provided an aperture correction is applied. Results from the Hermes-SWIRE survey in Lockman are also discussed briefly, and the strong contrast between the galaxy populations selected at 60 and 500 mu is summarized.

  3. Spectroscopic Infrared Ellipsometry

    E-print Network

    Eindhoven, Technische Universiteit

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

  4. Optical Selection of Faint Active Galactic Nuclei in the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Casey, C. M.; Impey, C. D.; Trump, J. R.; Gabor, J.; Abraham, R. G.; Capak, P.; Scoville, N. Z.; Brusa, M.; Schinnerer, E.

    2008-07-01

    We outline a strategy to select faint (iAB<24.5) type 1 active galactic nucleus (AGN) candidates down to the Seyfert/QSO boundary for spectroscopic targeting in the COSMOS field. Our selection process picks candidates by their nonstellar colors in uBVRizK broadband photometry from the Subaru and CFH Telescopes and morphological properties extracted from Hubble Space Telescope (HST) ACS i-band data. Although the COSMOS field has been used extensively to survey the faint galaxy population out to z~6, AGN optical color selection has not been applied to so faint a level in such a large continuous part of the sky. Hot stars are known to be the dominant contaminant for bright AGN candidate selection at z<2, but we anticipate the highest color contamination rate at all redshifts to be from faint starburst and compact galaxies. Morphological selection via the Gini Coefficient separates most potential AGNs from these faint blue galaxies. Recent models of the quasar luminosity function (QLF) from Hopkins et al. are used to estimate quasar surface densities, and a recent study of stellar populations in the COSMOS field is applied to infer stellar surface densities and contamination. We use 292 spectroscopically confirmed type 1 broad-line AGN and quasar templates to predict AGN colors as a function of redshift, and then contrast those predictions with the colors of known contaminating populations. Since the number of galaxy contaminants cannot be reliably identified with respect to stellar and predicted QLF numbers, the completeness and efficiency of the selection cannot be calculated before gathering confirming spectroscopic observations. Instead we offer an upper limit estimate to selection efficiency (about 50% for low-z and 20%-40% for intermediate-z and high-z) as well as the completeness and efficiency with respect to an X-ray point source population (from the COSMOS AGN Survey), in the range 20%-50%. The motivation of this study and subsequent spectroscopic follow-up is to populate and refine the faint end of the QLF, at both low and high redshifts, where the population of type 1 AGNs is presently not well known. The anticipated AGN observations will add to the ~300 already known AGNs in the COSMOS field, making COSMOS a densely packed field of quasars to be used to understand supermassive black holes and probe the structure of the intergalactic medium in the intervening volume.

  5. An infrared imaging search for low-mass companions to members of the young nearby beta Pic and Tucana/Horologium associations

    E-print Network

    Neuhäuser, R; Alves, J; Huélamo, N; Ott, T; Eckart, A; Neuh"auser, Ralph; Ott, Th.

    2003-01-01

    We present deep high dynamic range infrared images of young nearby stars in the Tucana/Horologium and beta Pic associations, all ~ 10 to 35 Myrs young and at ~10 to 60 pc distance. Such young nearby stars are well-suited for direct imaging searches for brown dwarf and even planetary companions, because young sub-stellar objects are still self-luminous due to contraction and accretion. We performed our observations at the ESO 3.5m NTT with the normal infrared imaging detector SofI and the MPE speckle camera Sharp-I. Three arc sec north of GSC 8047-0232 in Horologium a promising brown dwarf companion candidate is detected, which needs to be confirmed by proper motion and/or spectroscopy. Several other faint companion candidates are already rejected by second epoch imaging. Among 21 stars observed in Tucana/Horologium, there are not more than one to five brown dwarf companions outside of 75 AU (1.5" at 50 pc); most certainly only < 5 % of the Tuc/HorA stars have brown dwarf companions (13 to 78 Jupiter masses...

  6. EMISSION LINE PROPERTIES OF ACTIVE GALACTIC NUCLEI FROM A PRE-COSTAR FAINT OBJECT SPECTROGRAPH HUBBLE SPACE TELESCOPE SPECTRAL ATLAS

    E-print Network

    Green, Paul

    detailed information obtainable about the intrinsic properties of quasars. Studies of the density, ionization and metal abundance of gas near the accreting black hole are probed through an intriguing but poorly understood complex of correlations between emission lines and overall quasar spectral energy

  7. EMISSION LINE PROPERTIES OF ACTIVE GALACTIC NUCLEI FROM A POST-COSTAR HUBBLE SPACE TELESCOPE FAINT OBJECT SPECTROGRAPH SPECTRAL ATLAS

    E-print Network

    Green, Paul

    that the quasar central engine (presumably a massive black hole with an accretion disk) photoionizes gas lying farther out. This gas emits broad permitted emission lines that are distinctive of quasar spectra of properties (gas density, ionization flux, and column density), the bulk of emission line flux is most likely

  8. New `Moons' of Saturn May Be Transient Objects

    NASA Astrophysics Data System (ADS)

    1996-01-01

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

  9. Objective lens

    NASA Technical Reports Server (NTRS)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    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.

  10. Object identity

    Microsoft Academic Search

    Setrag N. Khoshafian; George P. Copeland

    1986-01-01

    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

  11. CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution Observations

    NASA Astrophysics Data System (ADS)

    Lebouteiller, V.; Barry, D. J.; Goes, C.; Sloan, G. C.; Spoon, H. W. W.; Weedman, D. W.; Bernard-Salas, J.; Houck, J. R.

    2015-06-01

    The Infrared Spectrograph (IRS) on board the Spitzer Space Telescope observed about 15,000 objects during the cryogenic mission lifetime. Observations provided low-resolution (R=? /{? }? ? 60-127) spectra over ? 5-38 ?m and high-resolution (R? 600) spectra over 10–37 ?m. The Cornell Atlas of Spitzer/IRS Sources (CASSIS) was created to provide publishable quality spectra to the community. Low-resolution spectra have been available in CASSIS since 2011, and here we present the addition of the high-resolution spectra. The high-resolution observations represent approximately one-third of all staring observations performed with the IRS instrument. While low-resolution observations are adapted to faint objects and/or broad spectral features (e.g., dust continuum, molecular bands), high-resolution observations allow more accurate measurements of narrow features (e.g., ionic emission lines) as well as a better sampling of the spectral profile of various features. Given the narrow aperture of the two high-resolution modules, cosmic ray hits and spurious features usually plague the spectra. Our pipeline is designed to minimize these effects through various improvements. A super-sampled point-spread function was created in order to enable the optimal extraction in addition to the full aperture extraction. The pipeline selects the best extraction method based on the spatial extent of the object. For unresolved sources, the optimal extraction provides a significant improvement in signal-to-noise ratio over a full aperture extraction. We have developed several techniques for optimal extraction, including a differential method that eliminates low-level rogue pixels (even when no dedicated background observation was performed). The updated CASSIS repository now includes all the spectra ever taken by the IRS, with the exception of mapping observations.

  12. Deep optical imaging of the field of PC1643+4631A&B, I: Spatial distributions and the counts of faint galaxies

    E-print Network

    Toby Haynes; Garret Cotter; Joanne C. Baker; Steve Eales; Michael E. Jones; Steve Rawlings; Richard Saunders

    1998-11-18

    We present deep optical images of the PC1643+4631 field obtained at the WHT. This field contains two quasars at redshifts z=3.79 & 3.83 and a cosmic microwave background (CMB) decrement detected with the Ryle Telescope. The images are in U,G,V,R and I filters, and are complete to 25th magnitude in R and G and to 25.5 in U. The isophotal galaxy counts are consistent with the results of Metcalde et al. (1996), Hogg et al. (1997), and others. We find an excess of robust high-redshift Ly-break galaxy candidates with 25.0object-finding algorithms of FOCAS and SExtractor: we find FOCAS the more efficient at detecting faint objects and the better at dealing with composite objects, whereas SExtractor's morphological classification is more reliable, especially for faint objects near the resolution limit. More generally, we have also compared the flux lost using isophotal apertures on a real image with that on a noise-only image: recovery of artificial galaxies from the noise-only image significantly overestimates the flux lost from the galaxies, and we find that the corrections made using this technique suffer a systematic error of some 0.4 magnitudes.

  13. Reference-less detection, astrometry, and photometry of faint companions with adaptive optics

    E-print Network

    Szymon Gladysz; Julian C. Christou

    2009-07-14

    We propose a complete framework for the detection, astrometry, and photometry of faint companions from a sequence of adaptive optics corrected short exposures. The algorithms exploit the difference in statistics between the on-axis and off-axis intensity. Using moderate-Strehl ratio data obtained with the natural guide star adaptive optics system on the Lick Observatory's 3-m Shane Telescope, we compare these methods to the standard approach of PSF fitting. We give detection limits for the Lick system, as well as a first guide to expected accuracy of differential photometry and astrometry with the new techniques. The proposed approach to detection offers a new way of determining dynamic range, while the new algorithms for differential photometry and astrometry yield accurate results for very faint and close-in companions where PSF fitting fails. All three proposed algorithms are self-calibrating, i.e. they do not require observation of a calibration star thus improving the observing efficiency.

  14. BIG FISH, LITTLE FISH: TWO NEW ULTRA-FAINT SATELLITES OF THE MILKY WAY

    SciTech Connect

    Belokurov, V.; Walker, M. G.; Evans, N. W.; Gilmore, G.; Irwin, M. J.; Koposov, S.; Watkins, L.; Wyrzykowski, L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Just, D.; Olszewski, E. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Mateo, M. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)], E-mail: vasily@ast.cam.ac.uk, E-mail: walker@ast.cam.ac.uk, E-mail: nwe@ast.cam.ac.uk

    2010-03-20

    We report the discovery of two new Milky Way satellites in the neighboring constellations of Pisces and Pegasus identified in data from the Sloan Digital Sky Survey. Pisces II, an ultra-faint dwarf galaxy lies at the distance of {approx}180 kpc, some 15 deg. away from the recently detected Pisces I. Segue 3, an ultra-faint star cluster lies at the distance of 16 kpc. We use deep follow-up imaging obtained with the 4-m Mayall Telescope at Kitt Peak National Observatory to derive their structural parameters. Pisces II has a half-light radius of {approx}60 pc, while Segue 3 is 20 times smaller at only 3 pc.

  15. Ultra-faint high-redshift galaxies in the Frontier Fields

    NASA Astrophysics Data System (ADS)

    Yue, B.; Ferrara, A.; Vanzella, E.; Salvaterra, R.

    2014-09-01

    By combining cosmological simulations with Frontier Field (FF) project lens models, we find that, in the most optimistic case, galaxies as faint as m ? 33-34 (AB magnitude at 1.6 ?m) can be detected in the Frontier Fields. Such faint galaxies are hosted by dark matter haloes of mass ˜109 M? and dominate the ionizing photon budget over currently observed bright galaxies, thus allowing for the first time the investigation of the dominant reionization sources. In addition, the observed number of these galaxies can be used to constrain the role of feedback in suppressing star formation in small haloes: for example, if galaxy formation is suppressed in haloes with circular velocity vc < 50 km s-1, galaxies fainter than m = 31 should not be detected in the FFs.

  16. Astrometric observations of the faint satellites of Jupiter and minor planets, 1974-1977

    NASA Technical Reports Server (NTRS)

    Benedict, G. R.; Shelus, P. J.; Mulholland, J. D.

    1978-01-01

    Precise positions of the faint satellites VI-XII of Jupiter during the 1974 opposition, and for Jupiter XIII during the 1976-1977 and 1977-1978 oppositions, have been obtained from plates taken with the 2.1-m Otto Struve reflector of the McDonald Observatory by the use of a new quasi-automatic plate measurement and reduction procedure on a PDS microdensitometer. Observations of selected asteroids, including two of 1977 UB (Chiron) are given also.

  17. MAXI/GSC detection of a faint X-ray transient MAXI J1957+032

    NASA Astrophysics Data System (ADS)

    Negoro, H.; Serino, M.; Mihara, T.; Nakahira, S.; Ueno, S.; Tomida, H.; Kimura, M.; Ishikawa, M.; Nakagawa, Y. E.; Sugizaki, M.; Shidatsu, M.; Sugimoto, J.; Takagi, T.; Matsuoka, M.; Kawai, N.; Yoshii, T.; Tachibana, Y.; Yoshida, A.; Sakamoto, T.; Kawakubo, Y.; Ohtsuki, H.; Tsunemi, H.; Imatani, R.; Nakajima, M.; Masumitsu, T.; Tanaka, K.; Ueda, Y.; Kawamuro, T.; Hori, T.; Tsuboi, Y.; Kanetou, S.; Yamauchi, M.; Itoh, D.; Yamaoka, K.; Morii, M.

    2015-05-01

    On 2015 May 11 (MJD 57153), MAXI/GSC detected a faint X-ray transient at the position (l, b) = (43.6, -13.1). From the data obtained from 13:59 on May 11 to 17:45 on May 12, we obtain the source position at (R.A., Dec) = (299.356 deg, 3.293 deg) = (19 57 25, +03 17 34) (J2000) with a statistical 90% C.L.

  18. The M\\/L Ratio of Distant Galaxies from Faint Counts and the K - z Diagram

    Microsoft Academic Search

    Brigitte Rocca-Volmerange

    2003-01-01

    Evolution scenarii of galaxies predict luminosity distributions and apparent ratios M\\/L as a function of z and type for various cosmogony and mass evolution schemes. Stellar emissions of elliptical to irregular galaxy populations,\\u000a after k- and e- corrections, are then compared to observations. The best constraints on evolution scenarii are, at the present\\u000a time, the deepest multispectral faint galaxy counts

  19. Increased phase synchronization and decreased cerebral autoregulation during fainting in the young.

    PubMed

    Ocon, Anthony J; Kulesa, John; Clarke, Debbie; Taneja, Indu; Medow, Marvin S; Stewart, Julian M

    2009-12-01

    Vasovagal syncope may be due to a transient cerebral hypoperfusion that accompanies frequency entrainment between arterial pressure (AP) and cerebral blood flow velocity (CBFV). We hypothesized that cerebral autoregulation fails during fainting; a phase synchronization index (PhSI) between AP and CBFV was used as a nonlinear, nonstationary, time-dependent measurement of cerebral autoregulation. Twelve healthy control subjects and twelve subjects with a history of vasovagal syncope underwent 10-min tilt table testing with the continuous measurement of AP, CBFV, heart rate (HR), end-tidal CO2 (ETCO2), and respiratory frequency. Time intervals were defined to compare physiologically equivalent periods in fainters and control subjects. A PhSI value of 0 corresponds to an absence of phase synchronization and efficient cerebral autoregulation, whereas a PhSI value of 1 corresponds to complete phase synchronization and inefficient cerebral autoregulation. During supine baseline conditions, both control and syncope groups demonstrated similar oscillatory changes in phase, with mean PhSI values of 0.58+/-0.04 and 0.54+/-0.02, respectively. Throughout tilt, control subjects demonstrated similar PhSI values compared with supine conditions. Approximately 2 min before fainting, syncopal subjects demonstrated a sharp decrease in PhSI (0.23+/-0.06), representing efficient cerebral autoregulation. Immediately after this period, PhSI increased sharply, suggesting inefficient cerebral autoregulation, and remained elevated at the time of faint (0.92+/-0.02) and during the early recovery period (0.79+/-0.04) immediately after the return to the supine position. Our data demonstrate rapid, biphasic changes in cerebral autoregulation, which are temporally related to vasovagal syncope. Thus, a sudden period of highly efficient cerebral autoregulation precedes the virtual loss of autoregulation, which continued during and after the faint. PMID:19820196

  20. Faint Radio Sources in the NOAO Bootes Field. VLBA Imaging And Optical Identifications

    SciTech Connect

    Wrobel, J.M.; /NRAO, Socorro; Taylor, Greg B.; /NRAO, Socorro /KIPAC, Menlo Park; Rector, T.A.; /NRAO, Socorro /Alaska U.; Myers, S.T.; /NRAO, Socorro; Fassnacht, C.D.; /UC,

    2005-06-13

    As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Booetes field. These 76 sources were selected from the FIRST catalog to have peak flux densities above 10 mJy at 5'' resolution and deconvolved major diameters of less than 3'' at 1.4 GHz. Fifty-five of these faint radio sources were identified with accretion-powered radio galaxies and quasars brighter than 25.5 mag in the optical I band. On VLA scales at 1.4 GHz, a measure of the compactness of the faint sources (the ratio of the peak flux density from FIRST to the integrated flux density from the NVSS catalog) spans the full range of possibilities arising from source-resolution effects. Thirty of the faint radio sources, or 39{sub -7}{sup +9}%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 {sigma} {approx} 2 mJy at 2 mas resolution. The VLBA detections occur through the full range of compactness ratios. The stronger VLBA detections can themselves serve as phase-reference calibrators, boding well for opening up much of the radio sky to VLBA imaging. For the adopted cosmology, the VLBA resolution corresponds to 17 pc or finer. Most VLBA detections are unresolved or slightly resolved but one is diffuse and five show either double or core-jet structures; the properties of these latter six are discussed in detail. Eight VLBA detections are unidentified and fainter than 25.5 mag in the optical I band; their properties are highlighted because they likely mark optically-obscured active nuclei at high redshift.

  1. A deep ROSAT survey - XI. Enhanced X-ray emission from faint galaxies

    Microsoft Academic Search

    N. Roche; R. E. Griffiths; R. della Ceca; T. Shanks; B. J. Boyle; I. Georgantopoulos; G. C. Stewart

    1996-01-01

    To investigate the contribution of faint galaxies to the ~1-keV X-ray background (XRB), we cross-correlate the positions of 2750 galaxies with 18<=R<=23 mag, detected on optical CCD images, with the unresolved fluctuations on a deep (74 ks) ROSAT PSPC image. We detect a positive and significant (5sigma) signal in the cross-correlation function, in good agreement with our previous results from

  2. Infrared and Optical Observations of GRB 030115 and its Extremely Red Host Galaxy: Implications for Dark Bursts

    NASA Technical Reports Server (NTRS)

    Levan, Andrew; Fruchter, Andrew; Rhoads, James; Mobasher, Bahram; Tanvir, Nial; Gorosabel, Javier; Rol, Evert; Kouveliotou, Chryssa; DellAntonio, Ian; Merrill, Javier

    2004-01-01

    We present near-infrared (a) and optical observations of the afterglow of GRB 030115. Discovered in an infrared search at Kitt Peak 5 hours after the burst trigger, this afterglow is the faintest ever observed in the R-band at such an early epoch, and exhibits very red colors, with R-K approximately equal to 6. The magnitude of the optical afterglow of GRB 030115 is fainter than many upper limits for other bursts, suggesting that without early nIR observations it would have been classified as a "dark" burst. Both the color and optical magnitude of the afterglow are likely due to dust extinction and indicate that at least some optical afterglows are observations were also taken of the host galaxy and the surrounding field. Photometric redshifts imply that the host, and a substantial number of faint galaxies in the field are at z approximately 2.5. The overdensity of galaxies is sufficiently great that GRB 030115 may have occurred in a rich high-redshift cluster. The host galaxy shows extremely red colors (R-K=5) and is the first GRB host to be classified as an Extreme Red Object (ERO). Some of the galaxies surrounding the host also show very red colors, while the majority of the cluster are much bluer, indicating ongoing unobscured star formation. As it is thought that much of high redshift star formation occurs in highly obscured environments it may well be that GRB 030115 represents a transition object, between the relatively unobscured afterglows seen to date and a population which are very heavily extinguished, even in the nIR.

  3. Faint-state transitions in the SW Sextantis nova-like variable, HS 0455+8315

    E-print Network

    Shears, Jeremy; Rodriguez-Gil, Pablo; Boyd, David; Darlington, Graham; Miller, Ian

    2015-01-01

    We present the fourteen year-long light curve of the SW Sextantis nova-like variable, HS 0455+8315, from 2000 November to 2015 February which reveals two deep faint states at magnitude 19 - 20, each of which lasted about 500 and 540 days. Outside these faint states, the star spent most of the time in a normal state at a magnitude of about 15.3. The second faint state was the better observed of the two and was found to have a linear decline of 0.009 mag/day, which was soon followed by a more rapid brightening at -0.020 mag/day. Time series photometry during both the normal state and near minimum light at about magnitude 18 showed that the eclipses had very similar profiles and that outside the eclipse there were irregular modulations typical of the flickering inherent to accreting CVs. Our photometry leading up to the minimum shows that accretion was still ongoing during this time.

  4. Double Pendulum: a Second Ultra-faint Milky Way Satellite in the Horologium Constellation

    E-print Network

    Kim, Dongwon

    2015-01-01

    We report the discovery of a new ultra-faint Milky Way satellite candidate, Horologium II, detected in the Dark Energy Survey Y1A1 public data. Horologium II features a half light radius of $r_{h}=47\\pm10$ pc and a total luminosity of $M_{V}=-2.6^{+0.2}_{-0.3}$ that place it in the realm of ultra-faint dwarf galaxies on the size-luminosity plane. The stellar population of the new satellite is consistent with an old ($\\sim13.5$ Gyr) and metal-poor ([Fe/H]$\\sim-2.1$) isochrone at a distance modulus of $(m-M)=19.46$, or a heliocentric distance of 78 kpc, in the color-magnitude diagram. Horologium II has a distance similar to the Sculptor dwarf spheroidal galaxy (79 kpc) and the recently reported ultra-faint satellites Eridanus III (87 kpc) and Horologium I (79 kpc). All four satellites are well aligned on the sky, which suggests a possible common origin. As Sculptor is moving on a retrograde orbit within the Vast Polar Structure when compared to the other classical MW satellite galaxies including the Magellanic ...

  5. The Faint End Slopes Of Galaxy Luminosity Functions In The COSMOS 2-Square Degree Field

    E-print Network

    Charles T. Liu; Peter Capak; Bahram Mobasher; Timothy A. D. Paglione; R. Michael Rich; Nicholas Z. Scoville; Shana M. Tribiano; Neil D. Tyson

    2007-08-11

    We examine the faint-end slope of the rest-frame V-band luminosity function (LF), with respect to galaxy spectral type, of field galaxies with redshift z<0.5, using a sample of 80,820 galaxies with photometric redshifts in the Cosmic Evolution Survey (COSMOS) field. For all galaxy spectral types combined, the LF slope, alpha, ranges from -1.24 to -1.12, from the lowest redshift bin to the highest. In the lowest redshift bin (0.02faint-end slopes grow shallower with increasing redshift; in the highest redshift bin (0.4faint dwarf galaxies, perhaps of low surface brightness, which are not detected at higher redshifts.

  6. Infrared observations of contaminants from shuttle flight 51-F

    Microsoft Academic Search

    D. G. Koch; G. G. Fazio; W. Hoffmann; G. Melnick; G. Rieke; J. Simpson; F. Witteborn; E. Young

    1987-01-01

    A small helium cooled infrared telescope, IRT, was flown on the Shuttle in July\\/August 1985. The principle astrophysical objectives were to measure the large scale structure of sources and the background radiation. A cold shutter was incorporated to permit absolute flux measurements. Additionally, the engineering objectives included setting upper limits on the infrared radiation from the local environment. Even though

  7. Motion detection using phase-based filtering in infrared imagery

    Microsoft Academic Search

    Wen-Shuai Yu; Xu-Chu Yu; Yi-Ming Zhang; Jing-Zheng Liu

    2009-01-01

    Detecting moving object is vital for dynamic imagery applications, for instance target tracking and target recognition. In thermal infrared image, the difficulties of the motion detection come from appearance changes of the objects, moving background or other causes. In this paper, we present a phase-based filtering method for motion detection in infrared images. Phase-based filtering is a frequency domain related

  8. Infrared astronomy - an assessment

    Microsoft Academic Search

    D. A. Allen

    1977-01-01

    An outline history of infrared astronomy is provided, taking into account the discovery of infrared radiation by Herschel in 1800 and the development of PbS and Ge:Ga detectors. Suitable locations and telescopes for infrared observatories are considered and the conduction of sky surveys is discussed. A description is presented of the results obtained with the aid of infrared astronomy in

  9. Portable infrared pupillometry: a review.

    PubMed

    Larson, Merlin D; Behrends, Matthias

    2015-06-01

    Portable infrared pupillometers provide an objective measure of pupil size and pupillary reflexes, which for most clinicians was previously only a visual impression. But despite the fact that pupillometry can uncover aspects of how the human pupil reacts to drugs and noxious stimulation, the use of pupillometry has not gained widespread use among anesthesiologists and critical care physicians. The present review is an introduction to the physiology of pupillary reflexes and the currently established clinical applications of infrared pupillometry, which will hopefully encourage physicians to use this diagnostic tool in their clinical practice. Portable infrared pupillometry was introduced in 1989. The technology involves flooding the eye with infrared light and then measuring the reflected image on an infrared sensor. Pupil size, along with variables of the pupillary light reflex and pupillary reflex dilation, is calculated by the instrument and displayed on a screen immediately after each time-stamped measurement. Use of these instruments has uncovered aspects of how the human pupil reacts to drugs and noxious stimulation. The primary clinical applications for portable pupillometry have been in the assessment of brainstem function. Portable pupillometry is useful in the management of pain because it allows for assessments of the effect of opioids and in the titration of combined regional-general anesthetics. PMID:25988634

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

    NASA Astrophysics Data System (ADS)

    Boselli, Alessandro; Gavazzi, Giuseppe

    2014-11-01

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

  11. Trusted Objects

    SciTech Connect

    CAMPBELL,PHILIP L.; PIERSON,LYNDON G.; WITZKE,EDWARD L.

    1999-10-27

    In the world of computers a trusted object is a collection of possibly-sensitive data and programs that can be allowed to reside and execute on a computer, even on an adversary's machine. Beyond the scope of one computer we believe that network-based agents in high-consequence and highly reliable applications will depend on this approach, and that the basis for such objects is what we call ''faithful execution.''

  12. The Coma cluster luminosity function from ultraviolet to near-infrared

    E-print Network

    S. Andreon; J. -C. Cuillandre; R. Pello

    2000-09-27

    [Abridged] The Coma cluster luminosity function (LF) from ultraviolet (2000 AA) to the near-infrared (H band) is summarized. In the UV the LF is very steep, much steeper than in the optical. The steep Coma UV LF implies that faint and bright galaxies give similar contributions to the total UV flux and to the total metal production rate. The Coma UV LF is dominated by star forming galaxies, not by massive and large galaxies. The optical Coma LF is relatively steep (alpha=-1.4) over the 11 magnitudes sampled. We found a clear steeping of the FL going from B to R bands, indicative of the presence of a large number of red dwarfs, as faint as three bright globular clusters. Furthermore, using Hubble Space Telescope images, we discover that blends of globular clusters, not resolved in individual components due to seeing, look like dwarf galaxies when observed from the ground and are numerous and bright. The existence of these fake extended sources increases the steepness of the LF at faint magnitudes, if not deal on. The near-infrared LF was computed on a near-infrared selected sample of galaxies which photometry is complete down to the typical dwarf (M^*+5) luminosity. The Coma LF can be described by a Schechter function with intermediate slope (alpha~-1.3), plus a dip at M_H~-22 mag. The shape of the Coma LF in H band is quite similar to the one found in the B band. The similarity of the LF in the optical and H bands implies that in the central region of Coma there is no new population of galaxies which is too faint to be observed in the optical band (because dust enshrouded, for instance), down to the magnitudes of dwarfs.

  13. Determining the nature of faint X-ray sources from the ASCA Galactic center survey

    NASA Astrophysics Data System (ADS)

    Lutovinov, A. A.; Revnivtsev, M. G.; Karasev, D. I.; Shimansky, V. V.; Burenin, R. A.; Bikmaev, I. F.; Vorob'ev, V. S.; Tsygankov, S. S.; Pavlinsky, M. N.

    2015-05-01

    We present the results of the the identification of six objects from the ASCA Galactic center and Galactic plane surveys: AX J173548-3207, AX J173628-3141, AX J1739.5-2910, AX J1740.4-2856, AX J1740.5-2937, and AX J1743.9-2846. Chandra, XMM-Newton, and XRT/Swift X-ray data have been used to improve the positions of the optical counterparts to these sources. Thereafter, we have carried out a series of spectroscopic observations of the established optical counterparts at the RTT-150 telescope. Analysis of X-ray and optical spectra as well as photometric measurements in a wide wavelength range based on optical and infrared catalogs has allowed the nature of the program sources to be determined. Two X-ray objects have been detected in the error circle of AX J173628-3141: one is a coronally active G star and the other may be a symbiotic star, a red giant with an accreting white dwarf. Three sources (AX J1739.5-2910, AX J1740.5-2937, AX J1743.9-2846) have turned out to be active G-K stars, presumably RS CVn objects, one (AX J1740.4-2856) is an M dwarf, and another one (AX J173548-3207) most likely a low-mass X-ray binary in its low state. The distances and corresponding luminosities of the sources in the soft X-ray band (0.5-10 keV) have been estimated; analysis of deep INTEGRAL Galactic center observations has not revealed a statistically significant flux at energies >20 keV from any of them.

  14. The faint end of the galaxy luminosity function in Abell 1689: a steep red faint end upturn at $z=0.18$

    E-print Network

    Banados, Eduardo; De Propris, Roberto; West, Michael

    2010-01-01

    We present a deep and wide $I$ luminosity function for galaxies in Abell 1689 ($z=0.183$) from a mosaic of HST WFPC2 images covering $10'$ on the side. The main result of this work is the detection of a steep upturn in the dwarf galaxy LF, with $\\alpha \\sim -2$. The dwarf to giant ratio appears to increase outwards, but this is because giant galaxies are missing in the cluster outskirts, indicating luminosity segregation. The red sequence LF has the same parameters, within errors, as the total LF, showing that the faint end upturn consists of red quiescent galaxies. We speculate that the upturn is connected to the `filling-in' of the red sequence at $z < 0.4$ and may represent the latest installment of `downsizing' as the least massive galaxies are being quenched at the present epoch.

  15. Unidentified Infrared Emission Features

    NASA Astrophysics Data System (ADS)

    Joblin, Christine

    2015-03-01

    When referring to unidentified infrared emission features, one has in mind the series of aromatic IR bands (AIBs) between 3.3 and 15 ?m that are observed in emission in many environments where UV photons irradiate interstellar matter. These bands are now used by astronomers to classify objects and characterize local physical conditions. However, a deep analysis cannot proceed without understanding the properties of the band carriers. Large polycyclic aromatic hydrocarbon molecules are attractive candidates but interstellar species are still poorly characterized. Various studies emphasize the need for tackling the link between molecular aromatic species, aliphatic material and very small carbonaceous grains. Other unidentified emission features such as the 6.9, 21 and 30 ?m bands could be involved in the evolutionary scenario.

  16. Infrared polarization and infrared variability of blazar

    NASA Astrophysics Data System (ADS)

    Mao, L. S.; Xie, G. Z.; Zhang, X.; Zhang, B. B.

    2006-04-01

    The correlation of the polarization in near-infrared and optical bands is studied by using the simultaneous observational data. It is found that the polarization degree, polarization angle and flux intensity of the near-infrared band are strongly correlated with those of the optical band. Therefore it is concluded that the near-infrared emission and polarization of blazars are mainly from synchrotron radiation. Finally, the correlations between J-H, H-K and J-K and the correlation between the near-infrared color indices and the magnitudes arw also studied.

  17. Objectively Speaking

    NSDL National Science Digital Library

    Brent, Rebecca, 1956-

    This resources is a column on how to write learning objectives for a course and why they make everything you do thereafter (e.g. planning syllabi and class sessions, making up assignments and exams, and reviewing departmental curricula) easier and more effective. Target Audience: 2-4 Year College Faculty/Administrators

  18. Comparison Between Four Detection Algorithms for GEO Objects

    NASA Astrophysics Data System (ADS)

    Yanagisawa, T.; Uetsuhara, M.; Banno, H.; Kurosaki, H.; Kinoshita, D.; Kitazawa, Y.; Hanada, T.

    2012-09-01

    Four detection algorithms for GEO objects are being developed under the collaboration between Kyushu University, IHI corporation and JAXA. Each algorithm is designed to process CCD images to detect GEO objects. First one is PC based stacking method which has been developed in JAXA since 2000. Numerous CCD images are used to detect faint GEO objects below the limiting magnitude of a single CCD image. Sub-images are cropped from many CCD image to fit the movement of the objects. A median image of all the sub-images is then created. Although this method has an ability to detect faint objects, it takes time to analyze. Second one is the line-identifying technique which also uses many CCD frames and finds any series of objects that are arrayed on a straight line from the first frame to the last frame. This can analyze data faster than the stacking method, but cannot detect faint objects as the stacking method. Third one is the robust stacking method developed by IHI corporation which uses average instead of median to reduce analysis time. This has same analysis speed as the line-identifying technique and better detection capabilities in terms of the darkness. Forth one is the FPGA based stacking method which uses binalized images and a new algorithm installed in a FPGA board which reduce analysis time about one thousandth. All four algorithms analyzed the same sets of data to evaluate their advantages and disadvantages. By comparing their analysis times and results, an optimal usage of these algorithms are considered.

  19. A near-infrared survey of the entire R Coronae Australis cloud

    NASA Astrophysics Data System (ADS)

    Haas, M.; Heymann, F.; Domke, I.; Drass, H.; Chini, R.; Hoffmeister, V.

    2008-09-01

    Aims: To understand low- to intermediate-mass star-formation in the nearby R Cr A molecular cloud, we try to identify the stellar content that is accessible with near-infrared observations. Methods: We obtained a JHKs band mosaic of ~10 arcmin × 60 arcmin covering the entire R CrA molecular cloud with unprecedented sensitivity. We present a catalogue of about 3500 near-infrared sources fainter than the saturation limit Ks ˜ 10 mag, reaching Ks ˜ 18 mag. We analysed the extended sources by inspecting their morphology and point sources by means of colour-colour and colour-magnitude diagrams. Additionally, we compared the extinction inferred from the NIR data with the line-of-sight dust emission at 1.2 mm. Sources towards high dust emission but relatively low H-Ks show a projected mm-excess; these sources are either immediately surrounded by cold circumstellar material or, if too red to be a true foreground object, they are embedded in the front layer of the 1.2 mm emitting dust cloud. In both cases they are most likely associated with the cloud. Results: By means of the projected mm-excess technique we find 33 new faint near-infrared sources deeply embedded in the Coronet cluster around R CrA, for which so far about 20 bright infrared stars have been known. In contrast to the Coronet region, both the northwestern dust ridge and the southeastern cloud condensation “C” appear to be devoid of associated stars detectable with our near-infrared data. Furthermore, about a dozen sources, which are spread over the entire molecular cloud region, exhibit a possible K-band excess, but only with marginal statistical significance (<3?), so that we do not consider the indicated K-band excess as real. Finally, while the Herbig-Haro-like objects seen on our maps are concentrated around the Coronet, we find four new nebulae also located farther down to the southeast. At the position of IRAS 18595-3712, an X-shaped bipolar nebula is resolved; its exciting star is hidden behind an edge-on disc. Conclusions: The deep near-infrared survey of the entire R CrA molecular cloud strengthens the evidence for the Coronet being the region where most of the young stars are found. Our results are consistent with earlier predictions that the R CrA cloud has fragmented into sub-condensations at different star-forming stages. Table A1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/488/987

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  1. The Faint Sub-mm Galaxy Population: HST Morphologies and Colors

    E-print Network

    Ian Smail; R. J. Ivison; A. W. Blain; J. -P. Kneib

    1998-06-04

    We present optical morphologies obtained from deep HST and ground-based images for galaxies selected from the first sub-millimeter survey of the distant Universe. Our sample comprises galaxies detected in deep 850-micron continuum maps of seven massive clusters, obtained using SCUBA, the new bolometer camera on the JCMT. The survey covers a total area of 0.01 square degrees to 1-sigma noise levels of about 2 mJy/beam. We detect a total of 25 sources at 850 microns, of which 17 and 10 are brighter than the respective 50% and 80% completeness limits. Optical counterparts are identified for 14 of the 16 sources in the f(50%) sample and for 9 of the 10 sources in the f(80%) sample that lie within our optical fields. The morphologies of those galaxies for which we have HST imaging fall into three broad categories: faint disturbed galaxies and interactions; faint galaxies too compact to classify reliably; and dusty, star-forming galaxies at intermediate redshifts. The disturbed and interacting galaxies constitute the largest class, which suggests that interactions remain an important mechanism for triggering star formation and the formation of ultraluminous galaxies in the distant Universe. The faint, compact galaxies may represent a later evolutionary stage in these mergers, or more centrally-concentrated starbursts. It is likely that some of these will host AGN. Analysis of the colors of our sample allow us to estimate a crude redshift distribution: >75% have z50% lie at zUV/optical surveys of the distant Universe. This imposes important constraints on models of galaxy formation and evolution.

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

    SciTech Connect

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

    2012-12-20

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

  3. Pre-reionization Fossils, Ultra-faint Dwarfs and the Missing Galactic Satellite Problem

    E-print Network

    Mia S. Bovill; Massimo Ricotti

    2009-03-09

    We argue that, at least a fraction of the newly discovered population of ultra-faint dwarf spheroidal galaxies in the Local Group constitute the fossil relic of a once ubiquitous population of dwarf galaxies formed before reionization with circular velocities smaller than $v_{c}^{cr} \\sim 20$ km/s. We present several arguments in support of this model. The number of luminous Milky Way satellites inferred from observations is larger than the estimated number of dark halos in the Galaxy that have, or had in the past, circular velocity $>v_{c}^{cr}$, as predicted by the "Via Lactea" simulation. This implies that some ultra-faint dwarfs are fossils. However, this argument is weakened by recent results from the "Aquarius" simulations showing that the number of Galactic dark matter satellites is 2.5 larger than previously believed. Secondly, the existence of a population of ultra-faint dwarfs was predicted by cosmological simulations in which star formation in the first minihalos is reduced -- but not suppressed -- by radiative feedback. Here, we show the statistical properties of the fossil galaxies in those simulations are consistent with observations of the new dwarf population and with the number and radial distribution of Milky Way satellites as a function of their luminosity. Finally, the observed Galactocentric distribution of dwarfs is consistent with a fraction of dSphs being fossils. To make our case more compelling, future work should determine whether stellar chemical abundances of simulated "fossils" can reproduce observations and whether the tidal scenarios for the formation of Local Group dwarf spheroidals are equally consistent with all available observations.

  4. Faint-meteor survey with a large-format CMOS sensor

    NASA Astrophysics Data System (ADS)

    Watanabe, J.; Enomoto, T.; Terai, T.; Kasuga, T.; Miyazaki, S.; Oota, K.; Muraoka, F.; Onishi, T.; Yamasaki, T.; Mito, H.; Aoki, T.; Soyano, T.; Tarusawa, K.; Matsunaga, N.; Sako, S.; Kobayashi, N.; Doi, M.

    2014-07-01

    For observing faint meteors, we need a large telescope or similar optics, which always give a restriction of the field of view. It is a kind of trade-off between the high sensitivity by using larger telescope and narrower field of view. Reconciling this contradiction, we need a large-format imaging detector together with fast readout for meteor observations. A high-sensitivity CMOS sensor of the large format was developed by Canon Inc. in 2010[1]. Its size is 202 mm×205 mm which makes it the largest one-chip CMOS sensor in the world, and approximately 40 times the size of Canon's largest commercial CMOS sensor as shown in the figure. The number of pixel is 1280×1248. Because the increased size of the new CMOS sensor allows more light to be gathered, it enables shooting in low-light environments. The sensor makes image capture possible in one-hundredth the amount of light required by a 35 mm full-frame CMOS sensor, facilitating the shooting of 60 frame-per-second video with a mere 0.3 lux of illumination. We tried to use this large-format CMOS sensor attached to the prime focus of the 1.05-m (F3.1) Schmidt telescope at the Kiso Observatory, University of Tokyo, for surveying faint meteors. The field of view is 3.3 by 3.3 degrees. Test observations including operation check of the system were carried out in January 2011, September 2011,and December 2012. Images were obtained at a time resolution of 60 frames per second. In this system, the limiting magnitude is estimated to be about 11-12. Because of the limitation of the data storage, full-power observations (14-bit data per 1/60 second) were performed for about one or two hours each night. During the first period, we can count a sporadic meteor every 5 seconds. This is about one order higher detection rate of the faint meteors compared with the previous work[2]. Assuming the height of faint meteors at 100 km, the derived flux of the sporadic meteors is about 5 × 10^{-4} km^{-2} sec^{-1}. The last run was performed during the active period of the Geminid meteor shower. We could take valuable data on December 12 and 13. The result will be given in this presentation, together with the future potential of the large format CMOS sensor.

  5. MASTER OT025704+494743 discovery near the faint unknown galaxy

    NASA Astrophysics Data System (ADS)

    Tyurina, N.; Lipunov, V.; Gorbovskoy, E.; Balanutsa, P.; Kornilov, V.; Belinski, A.; Shatskiy, N.; Kuvshinov, D.; Chazov, V.; Kuznetsov, A.; Zimnukhov, D.; Yurkov, V.; Kudelina, I.; Sergienko, Yu.; Varda, D.; Sinyakov, E.; Krushinski, V.; Zalozhnih, I.; Popov, A.; Ivanov, K.; Yazev, S.; Budnev, N.; Konstantinov, E.; Chuvalaev, O.; Poleschuk, V.; Gres, O.; Parhomenko, A. V.; Tlatov, A.; Dormidontov, D.; Shumkov, V.; Shurpakov, S.

    2011-10-01

    MASTER auto-detection system at Blagoveshchensk (MASTER-Amur) has discovered new optical transient source at the position of (R.A., Dec) = 02h 57m 04.61s +49d 47m 43.3s (J2000) at 2011-10-26.65 UT . The OT is seen at 2 images. We have reference images with no optical source. There is no minor planet at this place. The OT magnitude is V=16.9 , V_lim=18.5 . There is a faint galaxy at DSS image close to OT position.

  6. Digital image profilers for detecting faint sources which have bright companions

    NASA Technical Reports Server (NTRS)

    Morris, Elena; Flint, Graham; Slavey, Robert

    1992-01-01

    For this program, an image profiling system was developed which offers the potential for detecting extremely faint optical sources that are located in close proximity to bright companions. The approach employed is novel in three respects. First, it does not require an optical system wherein extraordinary measures must be taken to minimize diffraction and scatter. Second, it does not require detectors possessing either extreme uniformity in sensitivity or extreme temporal stability. Finally, the system can readily be calibrated, or nulled, in space by testing against an unresolved singular stellar source.

  7. The early faint sun paradox: Organic shielding of ultraviolet-labile greenhouse gases

    SciTech Connect

    Sagan, C. [Cornell Univ., Ithaca, NY (United States)] [Cornell Univ., Ithaca, NY (United States); Chyba, C. [Univ. of Arizona, Tucson, AZ (United States)] [Univ. of Arizona, Tucson, AZ (United States)

    1997-05-23

    Atmospheric mixing ratios of {approximately}10{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 amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing. 78 refs., 2 figs., 1 tab.

  8. Differential CCD photometry of faint asteroids in crowded star fields and nonphotometric sky conditions

    NASA Technical Reports Server (NTRS)

    Wisniewski, W. Z.; Mcmillan, R. S.

    1987-01-01

    It is demonstrated that the use of an imaging CCD detector array allows photometric observations of comparatively faint asteroids moving rapidly through a complex background of star images. The shortage of observing time is alleviated by taking advantage of the presence of comparison stars that are observed simultaneously on the CCD imaging area and at small angular separations from the asteroid. These reference stars allow the effects of thin cirrus clouds or haze to be compensated to a degree adequate for the acquisition of scientifically original data.

  9. Infrared Surveys for AGN

    E-print Network

    Harding E. Smith

    2002-03-06

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

  10. Wide-field Infrared Survey Explorer

    NASA Technical Reports Server (NTRS)

    Padgett, Deborah

    2012-01-01

    We present WISE (Wide-field Infrared Survey Explorer) mid-infrared photometry of young stellar object candidates in the Canis Majoris clouds at a distance of 1 kpc. WISE has identified 682 objects with apparent 12 and 22 micron excess emission in a 7 deg x 10 deg field around the CMa Rl cloud . While a substantial fraction of these candidates are likely galaxies, AGB stars, and artifacts from confusion along the galactic plane, others are part of a spectacular cluster of YSOs imaged by WISE along a dark filament in the R1 cloud. Palomar Double Spectrograph observations of several sources in this cluster confirm their identity as young A and B stars with strong emission lines. In this contribution, we plot the optical -mid-infrared spectral energy distribution for the WISE YSO candidates and discuss potential contaminants to the sample . The data demonstrate the utility of WISE in performing wide-area surveys for young stellar objects.

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

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

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

  12. Wireless infrared communications

    Microsoft Academic Search

    JOSEPH M. KAHN; JOHN R. BARRY

    1997-01-01

    The use of infrared radiation as a medium for high-speed short-range wireless digital communication is discussed. Available infrared links and local-area networks are described. Advantages and drawbacks of the infrared medium are compared to those of radio and microwave media. The physical characteristics of infrared channels using intensity modulation with direct detection (IM\\/DD) are presented including path losses and multipath

  13. Infrared Inspection Techniques 

    E-print Network

    Hill, A. B.; Bevers, D. V.

    1979-01-01

    Infrared scanning equipment has been used at Amoco's Texas City refinery since 1971 as an inspection tool. A camera scans the field of view and focuses the infrared radiation on a detector which converts the infrared signal to an electrical signal...

  14. Cosmic Infrared Background from Early Epochs - Searching for Signatures of the First Stars

    E-print Network

    A. Kashlinsky

    2007-09-04

    Cosmic infrared background (CIB) contains emission from epochs inaccessible to current telescopic studies, such as the era of the first stars. We discuss theoretical expectations for the CIB contributions from the early population of massive stars. We then present the latest results from the ongoing project by our team (Kashlinsky, Arendt, Mather & Moseley 2005,2007a,b,c,) to measure CIB fluctuations from early epochs using deep Spitzer data. The results show the existence of significant CIB fluctuations at the IRAC wavelengths (3.6 to 8 mic) which remain after removing galaxies down to very faint levels. These fluctuations must arise from populations that have a significant clustering component, but only low levels of the shot noise. Furthermore, there are no correlations between the source-subtracted IRAC maps and the corresponding fields observed with the HST ACS at optical wavelengths. Taken together, these data imply that 1) the sources producing the CIB fluctuations are individually faint with flux JWST.

  15. An XMM-Newton hard X-ray survey of ultraluminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Franceschini, A.; Braito, V.; Persic, M.; Della Ceca, R.; Bassani, L.; Cappi, M.; Malaguti, P.; Palumbo, G. G. C.; Risaliti, G.; Salvati, M.; Severgnini, P.

    2003-08-01

    XMM-Newton observations of 10 ultraluminous infrared galaxies (ULIRGs) from a 200-ks mini-survey programme are reported. The aim is to investigate in hard X-rays a complete ULIRG sample selected from the bright IRAS 60-?m catalogue. All sources are detected in X-rays, five of which for the first time. These observations confirm that ULIRGs are intrinsically faint X-ray sources, their observed X-ray luminosities being typically L2-10keV<= 1042-1043 erg s-1, whereas their bolometric (mostly infrared) luminosities are Lbol > 1045 erg s-1. In all sources we find evidence for thermal emission from hot plasma with a rather constant temperature kT~= 0.7 keV, dominating the X-ray spectra below 1 keV, and probably associated with a nuclear or circumnuclear starburst. This thermal emission appears uncorrelated with the far-infrared luminosity, suggesting that, in addition to the ongoing rate of star formation, other parameters may also affect it. The soft X-ray emission appears to be extended on a scale of ~30 kpc for Mrk 231 and IRAS 19254-7245, possible evidence of galactic superwinds. In these two sources, IRAS 20551-4250 and 23128-5919, we find evidence for the presence of hidden active galactic nuclei (AGNs), while a minor AGN contribution may be suspected also in IRAS 20100-4156. In particular, we have detected a strong (EW ~ 2 keV) Fe K line at 6.4 keV in the spectrum of IRAS 19254-7245 and a weaker one in Mrk 231, suggestive of deeply buried AGNs. For the other sources, the X-ray luminosities and spectral shapes are consistent with hot thermal plasma and X-ray binary emissions of mainly starburst origin. We find that the 2-10 keV luminosities in these sources, most probably due to high-mass X-ray binaries, are correlated with LFIR: both luminosities are good indicators of the current global star formation rate in the Galaxy. The composite nature of ULIRGs is then confirmed, with hints for a predominance of the starburst over the AGN phenomenon in these objects even when observed in hard X-rays.

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

    E-print Network

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

    2013-01-01

    We present initial results from a wide-field (30,000 deg^2) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and WISE surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because these objects are faint in optical bands and have near-infrared colors that are difficult to distinguish from background stars. To overcome these obstacles, we have cross-matched the Pan-STARRS1 (optical) and WISE (mid-IR) catalogs to produce a unique multi-wavelength database for finding ultracool dwarfs. As part of our initial discoveries, we have identified seven brown dwarfs in the L/T transition within 9-15 pc of the Sun. The L9.5 dwarf PSO J140.2308+45.6487 and the T1.5 dwarf PSO J307.6784+07.8263 (both independently discovered by Mace et al. 2013) show possible spectroscopic variability at the Y- and J-bands. Two more objects in our sample show evidence of photometric J-band variability, and two others are candidate unresolved binaries based on their spectra. We expect ...

  17. A new infrared sensor model based on imaging system parameters

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Mao, Hongxia; Dai, Yinghong; Wu, Jingli

    2014-11-01

    When infrared detection scene simulation, Target signature quantitative measurement, a high confidence sensor model should be developed. Generally, sensor model is developed by dividing an infrared sensor into three parts: optics, detector and electronic circuits. Then several Mathematics models describing those parts effect are developed, and a sensor model is integrated. In this way, the sensor model is based on strict mathematic theory. But this model needs a lot of parameters, some of which are very difficult to achieve. So this model have an advantage to analyze sensor model effect, and when to simulating Infrared detection scene or to analyzing quantitative measurement precision of faint target by actual infrared sensor, a sensor model which is based on parameters that can be achieved should be developed. This article presents a new sensor model. The input parameters includes: SiTF, MTF, Noise and so on, all of which can be achieved in laboratory or outfield. The sensor model is validated by point target experiment and four-bar target experiment, and the error is within 5%. The SiTF parameter can be achieved through the relation of blackbody radiation and sensor signal. The noise parameter can be achieved by nonuniform background sensor signal and SiTF. The MTF parameter is very important, but it is difficult to be measured directly, especially outfield. This article presents a method to inverse the MTF by point target observation experiment. This method can be used to inverse an actual sensor MTF outfield by star observation experiment.

  18. First Ultraviolet Spectropolarimetry of Radio-selected BL Lacertae Objects

    NASA Astrophysics Data System (ADS)

    Smith, Paul S.; Allen, Richard G.; Angel, J. R. P.

    1993-10-01

    We present ultraviolet spectropolarimetry of the BL Lac objects OJ 287 and 0754+100 (OI 090.4) acquired with the Faint Object Spectrograph of the Hubble Space Telescope. These are the first such observations of radio-selected BL Lac objects and the polarimetry spans the wavelength range 1580-3300 A in the observer's frame. Neither object exhibited emission-line features in their UV spectra. OJ 287 was very faint during the UV observations (V ~ 16). The UV linear polarization of this object was ~20%. There is no indication that the degree of polarization or the polarization position angle varies with wavelength. Nearly simultaneous optical ground-based measurements show that the polarization does not significantly change with wavelength out to ~8000 A. The UV and optical polarization of 0754+100 was ~8% and also wavelength-independent during the epoch of observation. These observations confirm that the synchrotron emission that dominates the optical continuum also dominates in the ultraviolet in these two BL Lac objects. There is no evidence for significant contributions to the UV/optical flux by other emission components, and we set limits on the brightness of nonsynchrotron continuum components.

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

    NASA Astrophysics Data System (ADS)

    Morganson, Eric; Blandford, Roger

    2009-09-01

    We present a stable procedure for defining and measuring the two point angular autocorrelation function, w(?) = [?/?0(V)]-?, 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 first time, that, on subarcsec scales, the correlation function exceeds unity. This correlation function is well fit by a power law with index ? ~ 2.5 and a ?0 = 10-0.1(V-25.8) arcsec. This is very different from the values of ? ~ 0.7 and ?0(r) = 10-0.4(r-21.5) arcsec associated with the gravitational clustering of brighter galaxies. This observed clustering probably reflects the presence of giant star-forming regions within galactic-scale potential wells. Its measurement enables a new approach to measuring the redshift distribution of the faintest sources in the sky.

  20. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson; Lewin, Walter H.; Kouveliotou, Chryssa; vanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    1998-01-01

    We have recently completed a search of 6 years of archival Burst and Transient Source Experiment (BATSE) data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running onboard the spacecraft. These "non-triggered" bursts can be combined with the "triggered" bursts detected onboard to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately 2 lower than could be studied previously. The value of the (V/V(max)) statistic (in Euclidean space) for the bursts we detect is 0.177 +/- 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s time scales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s time scale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the Universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. These results lend support to the conclusions of previous studies predicting that relatively few faint bursts are waiting to be found below the BATSE onboard detection threshold.

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

    SciTech Connect

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

    2011-07-10

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

  2. Cataclysmic Variables and a New Class of Faint UV Stars in the Globular Cluster NGC 6397

    E-print Network

    Adrienne M. Cool; Jonathan E. Grindlay; Haldan N. Cohn; Phyllis N. Lugger; Charles D. Bailyn

    1998-09-26

    We present evidence that the globular cluster NGC 6397 contains two distinct classes of centrally-concentrated UV-bright stars. Color-magnitude diagrams constructed from U, B, V, and I data obtained with the HST/WFPC2 reveal seven UV-bright stars fainter than the main-sequence turnoff, three of which had previously been identified as cataclysmic variables (CVs). Lightcurves of these stars show the characteristic ``flicker'' of CVs, as well as longer-term variability. A fourth star is identified as a CV candidate on the basis of its variability and UV excess. Three additional UV-bright stars show no photometric variability and have broad-band colors characteristic of B stars. These non-flickering UV stars are too faint to be extended horizontal branch stars. We suggest that they could be low-mass helium white dwarfs, formed when the evolution of a red giant is interrupted, due either to Roche-lobe overflow onto a binary companion, or to envelope ejection following a common-envelope phase in a tidal-capture binary. Alternatively, they could be very-low-mass core-He-burning stars. Both the CVs and the new class of faint UV stars are strongly concentrated toward the cluster center, to the extent that mass segregation from 2-body relaxation alone may be unable to explain their distribution.

  3. STELLAR ARCHEOLOGY IN THE GALACTIC HALO WITH ULTRA-FAINT DWARFS. VII. HERCULES

    SciTech Connect

    Musella, Ilaria; Ripepi, Vincenzo; Marconi, Marcella, E-mail: ilaria@na.astro.it, E-mail: ripepi@na.astro.it, E-mail: marcella@na.astro.it [INAF, Osservatorio Astronomico di Capodimonte, I-8013 Napoli (Italy); and others

    2012-09-10

    We present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes six fundamental-mode (ab-type) and three first-overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, (P{sub ab}) = 0.68 days ({sigma} = 0.03 days), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening, and distance to Hercules, for which we find [Fe/H] = -2.30 {+-} 0.15 dex, E(B - V) = 0.09 {+-} 0.02 mag, and (m - M){sub 0} = 20.6 {+-} 0.1 mag, in good agreement with the literature values. We have obtained a V, B - V color-magnitude diagram (CMD) of Hercules that reaches V {approx} 25 mag and extends beyond the galaxy's half-light radius over a total area of 40' Multiplication-Sign 36'. The CMD and the RR Lyrae stars indicate the presence of a population as old and metal-poor as (at least) the Galactic globular cluster M68.

  4. Biomediated Precipitation of Calcium Carbonate and Sulfur in a Faintly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.; Peng, X.; Qiao, H.

    2014-12-01

    A faintly acidic hot spring named "female Tower" (T=73.5 ?, pH=6.64 ) is located in the Jifei Geothermal Field?Yunnan province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite and sulfur, as reveals by XRD analysis. Scanning electron microscopy (SEM) analysis show the microbial mats are formed of various coccoid, rod and filamentous microbes. Transmission electron microscopy (TEM) analysis show that intracellular sulfur granules are commonly associated with these microbes. Energy dispersive X-ray spectrometer (EDS) analysis shows that the surface of microbes are mainly composed of Ca, C, O and S. A culture-independent molecular phylogenetic analysis demonstrates the majority of bacteria in the spring are sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We suggest that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the formation of sulfur granules intracellularly and extracellularly. In the meantime, this reaction increases the pH in ambient environments, which fosters the precipitation of calcium carbonate precipitation in the microbial mats. This study suggests that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in faintly acidic hot spring environments.

  5. The syndrome of absent or faint second heart sound, rapid systole and forward collapsing pulse.

    PubMed

    Nassim, M A

    1992-09-01

    A syndrome consisting of an absent or faint second heart sound, prominent cardiac impulse and non-regurgitant or forward collapse of the pulse is described. There was, moreover, no second sound or flow murmur audible in either the aortic or the pulmonary area even though the impulse and collapsing pulse suggested a hyperdynamic circulation; the upstroke was sharp but without the full waterhammer knock. It is argued that the dominant cause of the collapsing pulse will usually be vasodilation, that absence or faintness of the second sound is due to a narrow angle of divergence between the ventricular and arterial pressure decay curves, and that in marked contrast to aortic regurgitation the quality of the impulse derives from rapid systole of lightly loaded ventricles. Although they described its separate elements, pre-homeostatic era clinicians may have overlooked the syndrome in the belief that the heart regulated a largely passive circulation, regarding only primary intracardiac events and the first heart sound as important. Sir William Stokes nevertheless foresaw that alterations in the second sound might be due to changes in vascular tone as well as in elasticity. Wider recognition, deeper understanding and appropriate correction of this syndrome may prove both useful and enlightening. PMID:1428272

  6. Modal Filters for Infrared Interferometry

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  7. Infrared Universe Poster

    NSDL National Science Digital Library

    2000-01-01

    This educational poster contains images and information about what the universe looks like in the infrared. The back contains nine 8.5 in. x 11 in. panels that explain what infrared light is and why infrared astronomy is important. It also talks about light and the different colors and wavelengths of the electromagnetic spectrum. It explains atmospheric transmission and how infrared observations help in the search for planets. The back panels also contain details on the Herschel experiment. In a very simple way it teaches the students how Herschel discovered infrared light.

  8. Unidentified infrared features in proto-planetary nebulae

    NASA Technical Reports Server (NTRS)

    Kwok, S.; Hrivnak, B. J.

    1989-01-01

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

  9. The Spitzer Space Telescope Survey of the Orion A and B Molecular Clouds. I. A Census of Dusty Young Stellar Objects and a Study of Their Mid-infrared Variability

    NASA Astrophysics Data System (ADS)

    Megeath, S. T.; Gutermuth, R.; Muzerolle, J.; Kryukova, E.; Flaherty, K.; Hora, J. L.; Allen, L. E.; Hartmann, L.; Myers, P. C.; Pipher, J. L.; Stauffer, J.; Young, E. T.; Fazio, G. G.

    2012-12-01

    We present a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9 deg2 in five mid-IR bands spanning 3-24 ?m. The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. We identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; we search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 ?m bands. We find that 50% of the dusty YSOs show variability. The variations are typically small (~0.2 mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8 ?m variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots.

  10. LoCuSS: Exploring the selection of faint blue background galaxies for cluster weak-lensing

    E-print Network

    Ziparo, Felicia; Okabe, Nobuhiro; Haines, Chris P; Pereira, Maria J; Egami, Eiichi

    2015-01-01

    Cosmological constraints from galaxy clusters rely on accurate measurements of the mass and internal structure of clusters. An important source of systematic uncertainty in cluster mass and structure measurements is the secure selection of background galaxies that are gravitationally lensed by clusters. This issue has been shown to be particular severe for faint blue galaxies. We therefore explore the selection of faint blue background galaxies, by reference to photometric redshift catalogs derived from the COSMOS survey and our own observations of massive galaxy clusters at z~0.2. We show that methods relying on photometric redshifts of galaxies in/behind clusters based on observations through five filters, and on deep 30-band COSMOS photometric redshifts are both inadequate to identify safely faint blue background galaxies. This is due to the small number of filters used by the former, and absence of massive galaxy clusters at redshifts of interest in the latter. We therefore develop a pragmatic method to c...

  11. Kinematic Properties and Stellar Populations of Faint Early-Type Galaxies. I. Velocity Dispersion Measurements of Central Coma Galaxies

    E-print Network

    Ana Matkovic; Rafael Guzman

    2005-06-22

    We present velocity dispersion measurements for 69 faint early-type galaxies in the core of the Coma cluster, spanning -22.0Coma galaxies. Using the scatter in this relation, we constrain the range of galaxy ages as a function of their formation epoch for different formation scenarios. Assuming a strong coordination in the formation epoch of faint early-type systems in Coma, we find that most had to be formed at least 6 Gyrs ago and over a short 1 Gyr period.

  12. Dual-frequency microwave-enhanced infrared thermography

    Microsoft Academic Search

    Tianchen Shi; Gerhard O. Sauermann; Carey M. Rappaport; Charles A. DiMarzio

    2001-01-01

    Humanitarian landmine detection and clearance is one of the most challenging, difficult and time-consuming tasks to be completed with existing technologies. Infrared (IR) Imagery has been used to find differences in heat transfer on the surface of the soil due to a buried object. In this paper, we will describe a method, Dual Frequency Microwave Enhanced Infrared Thermography (MEIT). Heating

  13. Moisture Diffusivity Characteristics of Rough Rice Under Infrared Radiation Heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To design an efficient infrared (IR) dryer for rough rice, it is important to understand the drying behavior of rice grains under infrared heating. The objective of this study was to determine the moisture diffusivity and moisture diffusivity coefficient of rough rice under IR heating and cooling. ...

  14. HUBBLE'S INFRARED GALAXY GALLERY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronomers have used the NASA Hubble Space Telescope to produce an infrared 'photo essay' of spiral galaxies. By penetrating the dust clouds swirling around the centers of these galaxies, the telescope's infrared vision is offering fresh views of star birth. These six images, taken with the Near Infrared Camera and Multi-Object Spectrometer, showcase different views of spiral galaxies, from a face-on image of an entire galaxy to a close-up of a core. The top row shows spirals at diverse angles, from face-on, (left); to slightly tilted, (center); to edge-on, (right). The bottom row shows close-ups of the hubs of three galaxies. In these images, red corresponds to glowing hydrogen, the raw material for star birth. The red knots outlining the curving spiral arms in NGC 5653 and NGC 3593, for example, pinpoint rich star-forming regions where the surrounding hydrogen gas is heated by intense ultraviolet radiation from young, massive stars. In visible light, many of these regions can be hidden from view by the clouds of gas and dust in which they were born. The glowing hydrogen found inside the cores of these galaxies, as in NGC 6946, may be due to star birth; radiation from active galactic nuclei (AGN), which are powered by massive black holes; or a combination of both. White is light from middle-age stars. Clusters of stars appear as white dots, as in NGC 2903. The galaxy cores are mostly white because of their dense concentration of stars. The dark material seen in these images is dust. These galaxies are part of a Hubble census of about 100 spiral galaxies. Astronomers at Space Telescope Science Institute took these images to fill gaps in the scheduling of a campaign using the NICMOS-3 camera. The data were non-proprietary, and were made available to the entire astronomical community. Filters: Three filters were used: red, blue, and green. Red represents emission at the Paschen Alpha line (light from glowing hydrogen) at a wavelength of 1.87 microns. Blue shows the galaxies in near-infrared light, measured between 1.4 and 1.8 microns (H-band emission). Green is a mixture of the two. Distance of galaxies from Earth: NGC 5653 - 161 million light-years; NGC 3593 - 28 million light-years; NGC 891 - 24 million light-years; NGC 4826 - 19 million light-years; NGC 2903 - 25 million light-years; and NGC 6946 - 20 million light-years. Credits: Torsten Boeker, Space Telescope Science Institute, and NASA NOTE TO EDITORS: Image files and photo caption are available on the Internet at: http://oposite.stsci.edu/pubinfo/pr/1999/10 or via links in http://oposite.stsci.edu/pubinfo/latest.html and http://oposite.stsci.edu/pubinfo/pictures.html Higher resolution digital versions of (300 dpi JPEG and TIFF) of the release photo are available at: http://oposite.stsci.edu/pubinfo/pr/1999/10/extra-photos.html STScI press releases and other information are available automatically by sending an Internet electronic mail message to pio-request@stsci.edu. In the body of the message (not the subject line) users should type the word 'subscribe' (don't use quotes). The system will respond with a confirmation of the subscription, and users will receive new press releases as they are issued. To unsubscribe, send mail to pio-request@stsci.edu. Leave the subject line blank, and type 'unsubscribe' (don't use quotes) in the body of the message.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  16. Follow-up near-infrared spectroscopy of ultraluminous infrared galaxies observed by ISO

    NASA Astrophysics Data System (ADS)

    Dannerbauer, H.; Rigopoulou, D.; Lutz, D.; Genzel, R.; Sturm, E.; Moorwood, A. F. M.

    2005-10-01

    We present low resolution near-infrared spectroscopy of an unbiased sample of 24 ultraluminous infrared galaxies (ULIRGs), selected from samples previously observed spectroscopically in the mid-infrared with the Infrared Space Observatory (ISO). Qualitatively, the near-infrared spectra resemble those of starbursts. Only in one ULIRG, IRAS 04114-5117E, do we find spectroscopic evidence for AGN activity. The spectroscopic classification in the near-infrared is in very good agreement with the mid-infrared one. For a subset of our sample for which extinction corrections can be derived from Pa?and Br?, we find rather high Pa?luminosities, in accordance with the powering source of these galaxies being star formation. [FeII] emission is strong in ULIRGs and may be linked to starburst and superwind activity. Additionally, our sample includes two unusual objects. The first, IRAS F00183-7111, exhibits extreme [FeII] emission and the second, IRAS F23578-5307, is according to our knowledge one of the most luminous infrared galaxies in H2 rotation-vibration emission.

  17. Mid-Infrared and Near Infrared Calibrations for Nutritional Parameters of Triticale (Triticosecale) and Pea (Pisum sativum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Data is lacking about the relative effectiveness of diffuse reflectance Fourier transformed mid-infrared (MidIR) versus near infrared (NIR) spectroscopy for calibration development of forage constituents. The objective of this study was to develop MidIR and NIR calibrations for acid detergent fiber ...

  18. Multicolor Photometric Observations of Optical Candidates to Faint ROSAT X-ray Sources in a 1 deg$^2$ field of the BATC Survey

    E-print Network

    Haotong Zhang; Suijian Xue; David Burstein; Xu Zhou; Zhaoji Jiang; Hong Wu; Jun Ma; Jiansheng Chen; Zhenlong Zou

    2004-03-03

    We present optical candidates for 75 X-ray sources in a $\\sim 1$ deg$^2$ overlapping region with the medium deep ROSAT survey. These candidates are selected using the multi-color CCD imaging observations made for the T329 field of the Beijing-Arizona-Taipei-Connecticut (BATC) Sky Survey. These X-ray sources are relatively faint (CR $<< 0.2 s^{-1}$) and thus mostly are not included in the RBS catalog, they also remain as X-ray sources without optical candidates in a previous identification program carried out by the Hamburg Quasar Survey. Within their position-error circles, almost all the X-ray sources are observed to have one or more spatially associated optical candidates within them down to the magnitude $m_V \\sim 23.1$. We have classified 149 of 156 detected optical candidates with 73 of the 75 X-ray sources with a SED-based Object Classification Approach (SOCA). These optical candidates include: 31 QSOs, 39 stars, 37 starburst galaxies, 42 galaxies, and 7 "just" visible objects. We have also cross-correlated the positions of these optical objects with NED, the FIRST radio source catalog and the 2MASS catalog. Separately, we have also SED-classified the remaining 6011 objects in our field of view. Optical objects are found at the $6.5\\sigma$ level above what one would expect from a random distribution, only QSOs are over-represented in these error circles at greater than 4$\\sigma$ frequency. We estimate redshifts for all extragalactic objects, and find a good correspondence of our predicted redshift with the measured redshift (a mean error of 0.04 in $\\Delta z$. There appears to be a supercluster at z $\\sim$ 0.3-0.35 in this direction, including many of the galaxies in the X-ray error circles are found in this redshift range.

  19. The Faint Young Sun Paradox in the Context of Modern Cosmology

    E-print Network

    Dumin, Yurii V

    2015-01-01

    The Faint Young Sun Paradox comes from the fact that solar luminosity (2-4)x10^9 years ago was insufficient to support the Earth's temperature necessary for the efficient development of geological and biological evolution (particularly, for the existence of considerable volumes of liquid water). It remains unclear by now if the so-called greenhouse effect on the Earth can resolve this problem. An interesting alternative explanation was put forward recently by M.Krizek (New Ast. 2012, 17, 1), who suggested that planetary orbits expand with time due to the local Hubble effect, caused by the uniformly-distributed Dark Energy. Then, under a reasonable value of the local Hubble constant, it is easy to explain why the Earth was receiving an approximately constant amount of solar irradiation for a long period in the past and will continue to do so for a quite long time in future.

  20. Diagnoses made in a secondary care “fits, faints, and funny turns” clinic

    PubMed Central

    Hindley, D; Ali, A; Robson, C

    2006-01-01

    Aims To investigate the diagnoses made for children referred to a “fits, faints, and funny turns” clinic. Methods Prospective study of 380 children referred to a dedicated secondary care clinic over an eight year period. Results Twenty three per cent of children were given a final diagnosis of one of the childhood epilepsies, with 48% of these having a specific epilepsy syndrome. Syncope was the commonest cause of a non?epileptic event (syncope and reflex anoxic seizures comprised 100/238, 42%) but there were a wide variety of other causes. Fifty three events (14%) were unclassified and managed without a diagnostic label or treatment. Conclusions In children with funny turns referred to secondary care, the diagnostic possibilities are numerous; among non?epileptic events, syncopes predominate. The majority do not have epilepsy. Unclassifiable events with no clear epileptic or non?epileptic cause are common and can be safely managed expectantly. PMID:16492885

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

    NASA Astrophysics Data System (ADS)

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

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

  2. A Modified Adaptive Stochastic Resonance for Detecting Faint Signal in Sensors

    PubMed Central

    Huang, Qi; Liu, Jun; Li, Hengwei

    2007-01-01

    In this paper, an approach is presented to detect faint signals with strong noises in sensors by stochastic resonance (SR). We adopt the power spectrum as the evaluation tool of SR, which can be obtained by the fast Fourier transform (FFT). Furthermore, we introduce the adaptive filtering scheme to realize signal processing automatically. The key of the scheme is how to adjust the barrier height to satisfy the optimal condition of SR in the presence of any input. For the given input signal, we present an operable procedure to execute the adjustment scheme. An example utilizing one audio sensor to detect the fault information from the power supply is given. Simulation results show that the modified stochastic resonance scheme can effectively detect fault signal with strong noise.

  3. Infrared Yellowstone Gallery

    NSDL National Science Digital Library

    Linda Hermans-Killam, at NASA's Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology's, created this Web site featuring remarkable visible and infrared images of the geothermal features in Yellowstone National Park. Visitors can view Hot Springs, Geyser Runoff, Orange Spring Mound, and even a thermal infrared image of an elk. With short educational descriptions and links included under many of the images, students can learn how geysers, hot springs, and mudpots work.

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

    SciTech Connect

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

    2010-01-01

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

  5. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; VanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of 6 years of archival BATSE data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running on board the spacecraft. These "nontriggered" bursts can be combined with the "triggered" bursts detected on board to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately 2 lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 plus or minus 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s timescales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s timescale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. We use the peak flux distribution to derive a limit of 10% (99% confidence) on the fraction of the total burst rate that could be contributed by a spatially homogeneous (in Euclidean space) subpopulation of burst sources, such as type lb/c supernovae. These results lend support to the conclusions of previous studies predicting that relatively few faint "classical" GRBs will be found below the BATSE onboard detection threshold.

  6. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; vanParadus, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of six years of archival Burst and Transient Source Experiment (BATSE) data for gamma-ray bursts (GRBs) that were too faint to activate the real-time burst detection system running on board the spacecraft. These 'nontriggered' bursts can be combined with the 'triggered' bursts detected on board to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately two lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 +/- 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s timescales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s timescale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. We use the peak flux distribution to derive a limit of 10% (99% confidence) on the fraction of the total burst rate that could be contributed by a spatially homogeneous (in Euclidean space) subpopulation of burst sources, such as type Ib/c supernovae. These results lend support to the conclusions of previous studies predicting that relatively few faint 'classical' GRBs will be found below the BATSE onboard detection threshold.

  7. Stellar Archeology in the Galactic Halo with Ultra-faint Dwarfs. VII. Hercules

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    We present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes six fundamental-mode (ab-type) and three first-overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, langP abrang = 0.68 days (? = 0.03 days), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening, and distance to Hercules, for which we find [Fe/H] = -2.30 ± 0.15 dex, E(B - V) = 0.09 ± 0.02 mag, and (m - M)0 = 20.6 ± 0.1 mag, in good agreement with the literature values. We have obtained a V, B - V color-magnitude diagram (CMD) of Hercules that reaches V ~ 25 mag and extends beyond the galaxy's half-light radius over a total area of 40' × 36'. The CMD and the RR Lyrae stars indicate the presence of a population as old and metal-poor as (at least) the Galactic globular cluster M68. Based on data collected at the 2.5 m Isaac Newton Telescope, La Palma, Canary Islands, Spain, at the 4.2 m William Herschel Telescope, Roche de los Muchachos, Canary Islands, Spain, at the 2.2 m ESO/MPI telescope, La Silla, Chile, Proposal 079.D-0587, at the 2 m Liverpool Telescope, Roche de los Muchachos, Canary Islands, Spain, and at the 2 m Faulkes Telescope North, Haleakala Observatory, Hawaii, USA.

  8. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Space Infrared

    E-print Network

    Rebull, Luisa M.

    . As the universe expands, starlight from distant galaxies is shifted from blue to red and ultimately the thick dust that permeates the universe, unveiling new information about galaxies, stars and dusty discs into the infrared. Most radiation emitted by stars, galaxies and other objects in the early universe now lies

  9. Infrared observations of anonymous IRC sources

    NASA Technical Reports Server (NTRS)

    Strecker, D. W.; Ney, E. P.

    1974-01-01

    Infrared (0.9 to 18 microns) observations of 232 anonymous 2-micron Sky survey (IRC) sources are reported. Most of the objects appear to be late-type stars with little or no long-wave excess. About ten percent exhibit large excesses. Thirty-one of the brightest 11-micron sources have been remeasured to determine variability. These brighter objects appear to fall into two groups; one group resembles NML Tauri, while the other is like NML Cygni.

  10. High resolution infrared measurements

    NASA Technical Reports Server (NTRS)

    Kessler, B.; Cawley, Robert

    1990-01-01

    Sample ground based cloud radiance data from a high resolution infrared sensor are shown and the sensor characteristics are presented in detail. The purpose of the Infrared Analysis Measurement and Modeling Program (IRAMMP) is to establish a deterministic radiometric data base of cloud, sea, and littoral terrain clutter to be used to advance the design and development of Infrared Search and Track (IRST) systems as well as other infrared devices. The sensor is a dual band radiometric sensor and its description, together with that of the Data Acquisition System (DAS), are given. A schematic diagram of the sensor optics is shown.

  11. Estimating Star Formation Rates from Infrared and Radio Luminosities: The Origin of the Radio-Infrared Correlation

    E-print Network

    Eric F. Bell

    2002-12-05

    I have assembled a diverse sample of galaxies from the literature with far-ultraviolet (FUV), optical, infrared (IR) and radio luminosities to explore the calibration of radio-derived and IR-derived star formation (SF) rates, and the origin of the radio-IR correlation. By comparing the 8-1000 micron IR, which samples dust-reprocessed starlight, with direct stellar FUV emission, I show that the IR traces most of the SF in luminous L* galaxies but traces only a small fraction of the SF in faint ~0.01 L* galaxies. If radio emission were a perfect SF rate indicator, this effect would cause easily detectable curvature in the radio-IR correlation. Yet, the radio-IR correlation is nearly linear. This implies that the radio flux from low-luminosity galaxies is substantially suppressed, compared to brighter galaxies. This is naturally interpreted in terms of a decreasing efficiency of non-thermal radio emission in faint galaxies. Thus, the linearity of the radio-IR correlation is a conspiracy: both indicators underestimate the SF rate at low luminosities. SF rate calibrations which take into account this effect are presented, along with estimates of the random and systematic error associated with their use.

  12. Flux Tensor Constrained Geodesic Active Contours with Sensor Fusion for Persistent Object Tracking

    Microsoft Academic Search

    Filiz Bunyak; Kannappan Palaniappan; Sumit Kumar Nath; Gunasekaran Seetharaman

    2007-01-01

    This paper makes new contributions in motion detection, object segmentation and trajectory estimation to create a successful object tracking system. A new efficient motion detection algorithm referred to as the flux tensor is used to detect moving objects in infrared video without requiring background modeling or contour extraction. The flux tensor-based motion detector when applied to infrared video is more

  13. The Clementine longwave infrared camera

    SciTech Connect

    Priest, R.E.; Lewis, I.T.; Sewall, N.R.; Park, H.S.; Shannon, M.J.; Ledebuhr, A.G.; Pleasance, L.D. [Lawrence Livermore National Lab., CA (United States); Massie, M.A. [Pacific Advanced Technology, Solvang, CA (United States); Metschuleit, K. [Amber/A Raytheon Co., Goleta, CA (United States)

    1995-04-01

    The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. The longwave-infrared (LWIR) camera supplemented the UV/Visible and near-infrared mapping cameras providing limited strip coverage of the moon, giving insight to the thermal properties of the soils. This camera provided {approximately}100 m spatial resolution at 400 km periselene, and a 7 km across-track swath. This 2.1 kg camera using a 128 x 128 Mercury-Cadmium-Telluride (MCT) FPA viewed thermal emission of the lunar surface and lunar horizon in the 8.0 to 9.5 {micro}m wavelength region. A description of this light-weight, low power LWIR camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights.

  14. A Search for Exozodiacal Dust and Faint Companions Near Sirius, Procyon, and Altair with the NICMOS Coronagraph 1

    E-print Network

    Brown, Michael E.

    A Search for Exozodiacal Dust and Faint Companions Near Sirius, Procyon, and Altair with the NICMOS, Pasadena, CA 91125 ABSTRACT We observed Sirius, Altair, and Procyon with the NICMOS Coronagraph | interplanetary medium | stars: individual (Altair, Procyon, Sirius) | stars: low mass, brown dwarfs 1

  15. Exploration of faint absorption bands in the reflectance spectra of the asteroids by method of optimal smoothing: Vestoids

    Microsoft Academic Search

    D. I. Shestopalov; L. A. McFadden; L. F. Golubeva

    2007-01-01

    An optimization method of smoothing noisy spectra was developed to investigate faint absorption bands in the visual spectral region of reflectance spectra of asteroids and the compositional information derived from their analysis. The smoothing algorithm is called ``optimal'' because the algorithm determines the best running box size to separate weak absorption bands from the noise. The method is tested for

  16. Exploration of faint absorption bands in the reflectance spectra of the asteroids by method of optimal smoothing: Vestoids

    Microsoft Academic Search

    D. I. Shestopalov; L. A. McFadden; L. F. Golubeva

    2007-01-01

    An optimization method of smoothing noisy spectra was developed to investigate faint absorption bands in the visual spectral region of reflectance spectra of asteroids and the compositional information derived from their analysis. The smoothing algorithm is called “optimal” because the algorithm determines the best running box size to separate weak absorption bands from the noise. The method is tested for

  17. Space-based infrared near-Earth asteroid survey simulation

    Microsoft Academic Search

    Edward F. Tedesco; Karri Muinonen; Stephan D. Price

    2000-01-01

    We demonstrate the efficiency and effectiveness of using a satellite-based sensor with visual and infrared focal plane arrays to search for that subclass of Near-Earth Objects (NEOs) with orbits largely interior to the Earth’s orbit. A space-based visual-infrared system could detect approximately 97% of the Atens and 64% of the IEOs (the, as yet hypothetical, objects with orbits entirely Interior

  18. FEASIBILITY OF USING INFRARED HEATING FOR BLANCHING AND DEHYDRATION OF FRUITS AND VEGETABLES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate the feasibility of using medium and far infrared heating for blanching and dehydration of various fruits and vegetables. The infrared blanching was referred as infrared dry-blanching (IDB) in this study since no water or steam was used. A catalytic infra...

  19. Adaptive Optics Imaging of Solar System Objects

    NASA Technical Reports Server (NTRS)

    Roddier, Francois; Owen, Toby

    1997-01-01

    Most solar system objects have never been observed at wavelengths longer than the R band with an angular resolution better than 1 sec. The Hubble Space Telescope itself has only recently been equipped to observe in the infrared. However, because of its small diameter, the angular resolution is lower than that one can now achieved from the ground with adaptive optics, and time allocated to planetary science is limited. We have been using adaptive optics (AO) on a 4-m class telescope to obtain 0.1 sec resolution images solar system objects at far red and near infrared wavelengths (0.7-2.5 micron) which best discriminate their spectral signatures. Our efforts has been put into areas of research for which high angular resolution is essential, such as the mapping of Titan and of large asteroids, the dynamics and composition of Neptune stratospheric clouds, the infrared photometry of Pluto, Charon, and close satellites previously undetected from the ground.

  20. An ISOCAM survey through gravitationally lensing galaxy clusters. III. New results from mid-infrared observations of the cluster Abell 2219

    Microsoft Academic Search

    D. Coia; L. Metcalfe; B. McBreen; A. Biviano; I. Smail; B. Altieri; J.-P. Kneib; S. McBreen; C. Sanchez-Fernandez; B. O'Halloran

    2005-01-01

    The massive cluster of galaxies Abell 2219 (z = 0.228) with two spectacular gravitational lensing arcs was observed at 14.3 mum (hereafter 15 mum) with the Infrared Space Observatory and results were published by Barvainis et al. (\\\\cite{1999AJ....118..645B}). These observations have been reanalyzed using a method specifically designed for the detection of faint sources that had been applied to other

  1. An ISOCAM survey through gravitationally lensing galaxy clusters. III. New results from mid-infrared observations of th e cluster Abell 2219

    Microsoft Academic Search

    D. Coia; L. Metcalfe; B. McBreen; A. Biviano; I. Smail; B. Altieri; J.-P. Kneib; S. McBreen; C. Sanchez-Fernandez; B. O'Halloran

    2004-01-01

    The massive cluster of galaxies Abell 2219 (z = 0.228) was observed at 14.3\\u000a$\\\\mu$m with the Infrared Space Observatory and results were published by\\u000aBarvainis et al. (1999). These observations have been reanalyzed using a method\\u000aspecifically designed for the detection of faint sources that had been applied\\u000ato other clusters. Five new sources were detected and the resulting

  2. Propane gas leak detection by infrared absorption using carbon infrared emitter and infrared camera

    Microsoft Academic Search

    Naoya Kasai; Chihiro Tsuchiya; Takabumi Fukuda; Kazuyoshi Sekine; Takeru Sano; Tatsumi Takehana

    2011-01-01

    The present study investigated the ability of a system using a carbon infrared emitter (CIE) and an infrared (IR) camera to detect a combustible gas, propane. The CIE transmitted infrared at wavelengths ranging from 1 to 5?m, and the infrared absorption band of propane gas (3.37?m) was obtained using a bandpass filter to remove other infrared wavelengths. The intensity of

  3. Improved Electromechanical Infrared Sensor

    NASA Technical Reports Server (NTRS)

    Kenny, Thomas W.; Kaiser, William J.

    1994-01-01

    Proposed electromechanical infrared detector improved version of device described in "Micromachined Electron-Tunneling Infrared Detectors" (NPO-18413). Fabrication easier, and undesired sensitivity to acceleration reduced. In devices, diaphragms and other components made of micromachined silicon, and displacements of diaphragms measured by electron tunneling displacement transducer {see "Micromachined Tunneling Accelerometer" (NPO-18513)}. Improved version offers enhanced frequency response and less spurious response to acceleration.

  4. Multispectral infrared imaging interferometer

    NASA Technical Reports Server (NTRS)

    Potter, A. E., Jr.

    1971-01-01

    Device permitting simultaneous viewing of infrared images at different wavelengths consists of imaging lens, Michelson interferometer, array of infrared detectors, data processing equipment for Fourier transformation of detector signal, and image display unit. Invention is useful in earth resources applications, nondestructive testing, and medical diagnoses.

  5. Uncooled infrared sensor performance

    Microsoft Academic Search

    Peter L. Marasco; Eustace L. Dereniak

    1993-01-01

    The technology behind infrared focal plane arrays capable of operating at room temperature is discussed, emphasizing bolometric and pyroelectric devices. Theoretical limitations of thermal imagers operating at room temperature are explored and presented. The results of a survey cataloging the capabilities of currently available room temperature infrared focal plane arrays are presented. An example of how this technology could perform

  6. Faint Coronal Hard X-rays From Accelerated Electrons in Solar Flares

    NASA Astrophysics Data System (ADS)

    Glesener, Lindsay Erin

    Solar flares are huge explosions on the Sun that release a tremendous amount of energy from the coronal magnetic field, up to 1033 ergs, in a short time (100--1000 seconds), with much of the energy going into accelerated electrons and ions. An efficient acceleration mechanism is needed, but the details of this mechanism remain relatively unknown. A fraction of this explosive energy reaches the Earth in the form of energetic particles, producing geomagnetic storms and posing dangers to spaceborne instruments, astronauts, and Earthbound power grids. There are thus practical reasons, as well as intellectual ones, for wishing to understand this extraordinary form of energy release. Through imaging spectroscopy of the hard X-ray (HXR) emission from solar flares, the behavior of flare-accelerated electrons can be studied. The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI ) spacecraft launched in 2002 with the goal of better understanding flare particle acceleration. Using rotation modulation collimators, RHESSI is able to cover a wide energy range (3 keV--17 MeV) with fine angular and energy resolutions. RHESSI's success in the last 10 years in investigating the relationship between energetic electrons and ions, the nature of faint sources in the corona, the energy distribution of flares, and several other topics have significantly advanced the understanding of flares. But along with the wealth of information revealed by RHESSI come some clear observational challenges. Very few, if any, RHESSI observations have come close to imaging the electron acceleration region itself. This is undoubtedly due to a lack of both sensitivity (HXRs from electron beams in the tenuous corona are faint) and dynamic range (HXR sources at chromospheric flare footpoints are much brighter and tend to obscure faint coronal sources). Greater sensitivity is also required to investigate the role that small flares in the quiet Sun could play in heating the corona. The Focusing Optics X-ray Solar Imager (FOXSI ) is a developing project to address these observational difficulties. FOXSI is a sounding rocket payload developed under NASA's Low Cost Access to Space program. The project spearheads a shift to using direct imaging via focusing grazing-incidence HXR optics rather than the indirect Fourier techniques used by RHESSI and its predecessors. Such optics can attain higher sensitivity since photons are focused onto a small detector volume and have significantly better dynamic range than Fourier methods do. On November 2, 2012 the FOXSI rocket payload was flown for a 6-minute observation and successfully imaged a solar flare, providing the first focused HXR spectroscopic images of the Sun above 5 keV. The motivation, construction, testing, and flight of FOXSI will be described in this text, along with case studies on the use of RHESSI to analyze unique coronal HXR sources from two solar flares.

  7. First Science Results from SOFIA/FORCAST: The Mid-infrared View of the Compact H II Region W3A

    NASA Astrophysics Data System (ADS)

    Salgado, F.; Berné, O.; Adams, J. D.; Herter, T. L.; Gull, G.; Schoenwald, J.; Keller, L. D.; De Buizer, J. M.; Vacca, W. D.; Becklin, E. E.; Shuping, R. Y.; Tielens, A. G. G. M.; Zinnecker, H.

    2012-04-01

    The massive star-forming region W3 was observed with the faint object infrared camera for the SOFIA telescope as part of the Short Science program. The 6.4, 6.6, 7.7, 19.7, 24.2, 31.5, and 37.1 ?m bandpasses were used to observe the emission of polycyclic aromatic hydrocarbon (PAH) molecules, very small grains, and big grains. Optical depth and color temperature maps of W3A show that IRS2 has blown a bubble devoid of gas and dust of ~0.05 pc radius. It is embedded in a dusty shell of ionized gas that contributes 40% of the total 24 ?m emission of W3A. This dust component is mostly heated by far-ultraviolet, rather than trapped Ly? photons. This shell is itself surrounded by a thin (~0.01 pc) photodissociation region where PAHs show intense emission. The infrared spectral energy distribution (SED) of three different zones located at 8'', 20'', and 25'' from IRS2 shows that the peak of the SED shifts toward longer wavelengths, when moving away from the star. Adopting the stellar radiation field for these three positions, DUSTEM model fits to these SEDs yield a dust-to-gas mass ratio in the ionized gas similar to that in the diffuse interstellar medium (ISM). However, the ratio of the IR-to-UV opacity of the dust in the ionized shell is increased by a factor of sime3 compared to the diffuse ISM.

  8. COS Target Acquisition Guidelines and Bright Object Protection Rules

    NASA Astrophysics Data System (ADS)

    Shaw, Brittany L.; Friedman, S.; Keyes, T.; Soderblom, D.

    2007-12-01

    The Cosmic Origins Spectrograph will provide unparalleled high sensitivity spectroscopy of faint ultraviolet sources. To effectively utilize the unique capabilities of COS, target selection and acquisitions should be carefully planned. Acquisitions of faint objects with COS will typically use the NUV imaging mode. For brighter sources, spiral search and peakup acquisition modes are available for both FUV and NUV. We highlight guidelines and strategies for observers to craft target acquisitions with all modes and how to choose between them. Based upon COS Exposure Time Calculator (ETC) modeling, we illustrate the time requirements for different target acquisition scenarios. To preserve the health and safety of COS detectors, separate bright object protection rules have been created for each detector. We explain these rules and their implications for potential COS targets and users. Most science observations will be performed in TIME-TAG mode in which individual photon arrival times and locations are recorded. This mode is preferred because it allows for optimized data reduction. Brighter objects that produce high count rates must be handled by using ACCUM mode that collects photons only by location on the detector. We discuss the count rate limits and specific data quality considerations of each mode.

  9. COS Target Acquisition Guidelines and Bright Object Protection Rules

    NASA Astrophysics Data System (ADS)

    Ghavamian, Parviz; Keyes, T.; Shaw, B.; Soderblom, D.; Friedman, S.; COS/STIS STScI Team; COS IDT Team

    2008-05-01

    The Cosmic Origins Spectrograph will provide spectroscopy of faint ultraviolet sources with unparalleled sensitivity. However, careful planning is required to effectively utilize the unique capabilities of COS. Faint object acquisition with COS will typically utilize the Near-UV (NUV) imaging mode. For brighter sources, spiral search and peakup acquisition modes are available for both the NUV and Far-UV (FUV). Here we highlight guidelines and strategies for observers to craft target acquisitions in all modes and describe how to choose between them. Based upon COS Exposure Time Calculator (ETC) modeling, we illustrate the time requirements for different target acquisition scenarios. To preserve the health and safety of COS detectors, separate bright object protection rules have been created for each detector. We explain these rules and their implications for potential COS targets and users. Most science observations will be performed in time-tag (TTAG) mode in which individual photon arrival times and locations are recorded. This mode is preferred because it allows for optimized data reduction. Brighter objects that produce high count rates must be handled by using accumulation (ACCUM) mode that collects photons according to their location on the detector. For each observation mode we discuss the count rate limits and specific data quality considerations.

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

    NASA Astrophysics Data System (ADS)

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

    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. In order to prepare students and teachers at this level with a high level of rigor and scientific understanding, the WISE and the Spitzer Space Tele-scope Education programs provided an immersive teacher professional development workshop in infrared astronomy.The lessons learned from the Spitzer and WISE teacher and student pro-grams can be applied to other programs engaging them in authentic research experiences using data from space-borne observatories such as Herschel and Planck. Recently, WISE Educator Ambassadors and NASA Explorer School teachers developed and led an infrared astronomy workshop at Arecibo Observatory in PuertoRico. As many common misconceptions involve scale and distance, teachers worked with Moon/Earth scale, solar system scale, and distance and age of objects in the Universe. Teachers built and used basic telescopes, learned about the history of telescopes, explored ground and satellite based telescopes, and explored and worked on models of WISE Telescope. An in-depth explanation of WISE and the Spitzer telescopes gave participants background knowledge for infrared astronomy observations. We taught the electromagnetic spectrum through interactive stations. We will outline specific steps for sec-ondary astronomy professional development, detail student involvement in infrared telescope data analysis, provide data demonstrating the impact of the above professional development on educator understanding and classroom use, and detail future plans for additional secondary professional development and student involvement in infrared astronomy. Funding was provided by NASA, WISE Telescope, the Spitzer Space Telescope, the American Institute of Aeronautics and Astronautics, the National Optical Astronomy Observatory, Starbucks, and Washington Space Grant Consortium.

  11. Development of the first infrared satellite observatory

    NASA Technical Reports Server (NTRS)

    Smith, G. M.; Squibb, G. F.

    1984-01-01

    A development history is given for the Infrared Astronomical Satelite (IRAS), whose primary mission objective is an unbiased, all-sky survey in the 8-120 micron wavelength range. A point source catalog of more than 200,000 IR sources, to be published later this year, represents the accomplishment of this objective. IRAS has also conducted 10,000 pointed observations of specific objects. Attention is given to the cost increases and schedule slips which resulted from the substantial technical challenges of IRAS hardware and software development, and to the management techniques which had to be employed in this major international project.

  12. Infrared point sensors for homeland defense applications

    NASA Astrophysics Data System (ADS)

    Thomas, Ross C.; Carter, Michael T.; Homrighausen, Craig L.

    2004-03-01

    We report recent progress toward the development of infrared point sensors for the detection of chemical warfare agents and explosive related chemicals, which pose a significant threat to both health and environment. Technical objectives have focused on the development of polymer sorbents to enhance the infrared response of these hazardous organic compounds. For example, infrared point sensors which part-per-billion detection limits have been developed that rapidlypartition chemical warfare agents and explosive related chemicals into polymer thin films with desirable chemical and physical properties. These chemical sensors demonstrate novel routes to reversible sensing of hazardous organic compounds. The development of small, low-power, sensitive, and selective instruments employing these chemical sensors would enhance the capabilities of federal, state, and local emergency response to incidents involving chemical terrorism. Specific applications include chemical defense systems for military personnel and homeland defense, environmental monitors for remediation and demilitarization, and point source detectors for emergency and maintenance response teams.

  13. The faint young Sun paradox: an observational test of an alternative solar model.

    PubMed

    Gaidos, E J; Gudel, M; Blake, G A

    2000-02-15

    We report the results of deep observations at radio (3.6 cm) wavelengths of the nearby solar-type star pi 01 Ursa Majoris with the Very Large Array (VLA) intended to test an alternative theory of solar luminosity evolution. The standard model predicts a solar luminosity only 75% of the present value and surface temperatures below freezing on Earth and Mars at 4 Ga, seemingly in conflict with geologic evidence for liquid water on these planets. An alternative model invokes a compensatory mass loss through a declining solar wind that results in a more consistent early luminosity. The free-free emission from an enhanced wind around nearby young Sun-like stars should be detectable at microwave frequencies. Our observations of pi 01 UMa, a 300 million year-old solar-mass star, place an upper limit on the mass loss rate of 4-5 x 10(-11) M(solar) yr-1. Total mass loss from such a star over 4 Gyr would be less than 6%. If this star is indeed an analog of the early Sun, it casts doubt on the alternative model as a solution to the faint young Sun paradox, particularly for Mars. PMID:11543273

  14. HAT-P-9b: A Low-Density Planet Transiting a Moderately Faint F Star

    NASA Astrophysics Data System (ADS)

    Shporer, Avi; Bakos, GÁspÁr Á.; Bouchy, Francois; Pont, Frederic; Kovács, Géza; Latham, Dave W.; Sipöcz, Brigitta; Torres, Guillermo; Mazeh, Tsevi; Esquerdo, Gilbert A.; Pál, András; Noyes, Robert W.; Sasselov, Dimitar D.; Lázár, József; Papp, István; Sári, Pál; Kovács, Gábor

    2009-01-01

    We report the discovery of a planet transiting a moderately faint (V = 12.3 mag) late F star, with an orbital period of 3.92289 ± 0.00004 days. From the transit light curve and radial velocity measurements, we determine that the radius of the planet is Rp = 1.40 ± 0.06 R Jup and that the mass is Mp = 0.78 ± 0.09 M Jup. The density of the new planet, ? p = 0.35 ± 0.06 g cm-3, fits to the low-density tail of the currently known transiting planets. We find that the center of transit is at T c = 2454417.9077 ± 0.0003 (HJD), and the total transit duration is 0.143 ± 0.004 days. The host star has M sstarf = 1.28 ± 0.13 M sun and R sstarf = 1.32 ± 0.07 R sun. Based in part on radial velocities obtained with the SOPHIE spectrograph mounted on the 1.93 m telescope at the Observatoire de Haute Provence, France (runs 07A.PNP.MAZE, 07B.PNP.MAZE, 08A.PNP.MAZE).

  15. X- and ?-Ray Pulsations of the Nearby Radio-faint PSR J1741-2054

    NASA Astrophysics Data System (ADS)

    Marelli, M.; Belfiore, A.; Saz Parkinson, P.; Caraveo, P.; De Luca, A.; Sarazin, C.; Salvetti, D.; Sivakoff, G. R.; Camilo, F.

    2014-07-01

    We report the results of a deep XMM-Newton observation of the radio-faint ?-ray pulsar J1741-2054 and its nebula together with the analysis of five years of Fermi Large Area Telescope (LAT) data. The X-ray spectrum of the pulsar is consistent with an absorbed power law plus a blackbody, originating at least partly from the neutron star cooling. The nebular emission is consistent with that of a synchrotron pulsar wind nebula, with hints of spatial spectral variation. We extended the available Fermi LAT ephemeris and folded the ?-ray and X-ray data. We detected X-ray pulsations from the neutron star: both the thermal and non-thermal components are ~35%-40% pulsed, with phase-aligned maxima. A sinusoid fits the thermal-folded profile well. A 10 bin phase-resolved analysis of the X-ray emission shows softening of the non-thermal spectrum during the on-pulse phases. The radio, X-ray, and ?-ray light curves are single-peaked, not phase-aligned, with the X-ray peak trailing the ?-ray peak by more than half a rotation. Spectral considerations suggest that the most probable pulsar distance is in the 0.3-1.0 kpc range, in agreement with the radio dispersion measure.

  16. Stellar Kinematics and Metallicities in the Ultra-Faint Dwarf Galaxy Reticulum II

    E-print Network

    Simon, J D; Li, T S; Nord, B; Geha, M; Bechtol, K; Balbinot, E; Buckley-Geer, E; Lin, H; Marshall, J; Santiago, B; Strigari, L; Wang, M; Wechsler, R H; Yanny, B; Abbott, T; Bauer, A H; Bernstein, G M; Bertin, E; Brooks, D; Burke, D L; Capozzi, D; Rosell, A Carnero; Kind, M Carrasco; D'Andrea, C B; da Costa, L N; DePoy, D L; Desai, S; Diehl, H T; Dodelson, S; Cunha, C E; Estrada, J; Evrard, A E; Neto, A Fausti; Fernandez, E; Finley, D A; Flaugher, B; Frieman, J; Gaztanaga, E; Gerdes, D; Gruen, D; Gruendl, R A; Honscheid, K; James, D; Kuehn, K; Kuropatkin, N; Lahav, O; Maia, M A G; March, M; Martini, P; Miller, C J; Miquel, R; Ogando, R; Romer, A K; Roodman, A; Rykoff, E S; Sako, M; Sanchez, E; Schubnell, M; Sevilla, I; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thaler, J; Tucker, D; Vikram, V; Walker, A R; Wester, W

    2015-01-01

    We present Magellan/M2FS, VLT/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8 +/- 0.5 km/s and a velocity dispersion of 3.3 +/- 0.7 km/s. The mass-to-light ratio of Ret II within its half-light radius is 470 +/- 210 Msun/Lsun, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 km/s, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 +/- 0.09 dex, and we identify several extremely metal-poor stars with [Fe/H] < -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a me...

  17. Radio observations of Circinus X-1 over a complete orbit at an historically faint epoch

    E-print Network

    Calvelo, D E; Tzioumis, A K; Kawai, N; Broderick, J W; Bell, M E

    2011-01-01

    We present results from the first radio observations of a complete orbit (~ 17 days) of the neutron star X-ray binary Circinus X-1 using the Australia Telescope Compact Array Broadband Backend, taken while the system was in an historically faint state. We have captured the rapid rise and decline of a periastron passage flare, with flux densities for 9 days prior to the event stable at ~ 1 mJy at 5.5 GHz and ~ 0.5 mJy at 9 GHz. The highest flux densities of 43.0 +/- 0.5 mJy at 5.5 GHz and 29.9 +/- 0.6 mJy at 9 GHz were measured during the flare's decline (MJD 55206.69) which continues towards pre-flare flux densities over the following 6 days. Imaging of pre-flare data reveals steady structure including two stable components within 15 arc-seconds of the core which we believe may be persistent emission regions within the system's outflows, one of which is likely associated with the system's counter-jet. Unlike past observations carried out in the system's brighter epochs, we observe no significant structural va...

  18. The faint young Sun paradox: an observational test of an alternative solar model

    NASA Technical Reports Server (NTRS)

    Gaidos, E. J.; Gudel, M.; Blake, G. A.

    2000-01-01

    We report the results of deep observations at radio (3.6 cm) wavelengths of the nearby solar-type star pi 01 Ursa Majoris with the Very Large Array (VLA) intended to test an alternative theory of solar luminosity evolution. The standard model predicts a solar luminosity only 75% of the present value and surface temperatures below freezing on Earth and Mars at 4 Ga, seemingly in conflict with geologic evidence for liquid water on these planets. An alternative model invokes a compensatory mass loss through a declining solar wind that results in a more consistent early luminosity. The free-free emission from an enhanced wind around nearby young Sun-like stars should be detectable at microwave frequencies. Our observations of pi 01 UMa, a 300 million year-old solar-mass star, place an upper limit on the mass loss rate of 4-5 x 10(-11) M(solar) yr-1. Total mass loss from such a star over 4 Gyr would be less than 6%. If this star is indeed an analog of the early Sun, it casts doubt on the alternative model as a solution to the faint young Sun paradox, particularly for Mars.

  19. New Horizons Mission Planning Support: A Deep Search for Faint Rings of Pluto

    NASA Astrophysics Data System (ADS)

    Showalter, Mark

    2010-09-01

    With the discoveries of Hydra and Nix, dwarf planet Pluto centers a more extensive satellite system than any terrestrial planet. Small moons are usually accompanied by rings of faint dust, which arise from impacts into their surfaces. Such rings show interesting dynamics including the influence of non-gravitational forces such as radiation pressure and Poynting-Robertson drag. A previous search for rings of Pluto in HST images was negative, but was limited by the scattered light from Pluto and Charon. Our more optimized plan will enable us to model and subtract out the scattered light pattern, yielding a detection threshold 10-30 times fainter than the prior limit. If Pluto sports a ring comparable to the major dust rings of the giant planets, our observing plan should detect it. This work supports the New Horizons mission by potentially revealing a dust hazard that might endanger the spacecraft during its 2015 flyby. It could also enhance the science return by allowing planners to target a known feature rather than conducting a more resource-intensive general search for rings. We request Director's Discretionary time because the Pluto observing sequence will be finalized in 2011; thus the observing window in June represents our last chance to obtain results that could influence the mission.

  20. GHOSTS I: A new faint very isolated dwarf galaxy at D = 12 ± 2 Mpc

    SciTech Connect

    Monachesi, Antonela; Bell, Eric F. [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Radburn-Smith, David J.; Dalcanton, Julianne J. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); De Jong, Roelof S.; Streich, David; Vlaji?, Marija [Leibniz-Institut für Astrophysik Potsdam, D-14482 Potsdam (Germany); Bailin, Jeremy [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Holwerda, Benne W. [European Space Agency Research Fellow (ESTEC), Keplerlaan 1, 2200-AG Noordwijk (Netherlands); Alyson Ford, H. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Zucker, Daniel B., E-mail: antonela@umich.edu [Department of Physics and Astronomy, E7A 317, Macquarie University, Sydney, NSW 2109 (Australia)

    2014-01-10

    We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color-magnitude diagrams (CMDs) to compare with the galaxy's CMD, we find that the colors and magnitudes of GHOSTS I's individual stars are most consistent with being young helium-burning and asymptotic giant branch stars at a distance of ?12 ± 2 Mpc. Morphologically, GHOSTS I appears to be actively forming stars, so we tentatively classify it as a dwarf irregular (dIrr) galaxy, although future Hubble Space Telescope (HST) observations deep enough to resolve a larger magnitude range in its LF are required to make a more secure classification. GHOSTS I's absolute magnitude is M{sub V}??9.85{sub ?0.33}{sup +0.40}, making it one of the least luminous dIrr galaxies known, and its metallicity is lower than [Fe/H] = –1.5 dex. The half-light radius of GHOSTS I is 226 ± 38 pc and its ellipticity is 0.47 ± 0.07, similar to Milky Way and M31 dwarf satellites at comparable luminosity. There are no luminous massive galaxies or galaxy clusters within ?4 Mpc from GHOSTS I that could be considered as its host, making it a very isolated dwarf galaxy in the local universe.

  1. Geological sulfur isotopes indicate elevated OCS in the Archean atmosphere, solving faint young sun paradox

    PubMed Central

    Ueno, Yuichiro; Johnson, Matthew S.; Danielache, Sebastian O.; Eskebjerg, Carsten; Pandey, Antra; Yoshida, Naohiro

    2009-01-01

    Distributions of sulfur isotopes in geological samples would provide a record of atmospheric composition if the mechanism producing the isotope effects could be described quantitatively. We determined the UV absorption spectra of 32SO2, 33SO2, and 34SO2 and use them to interpret the geological record. The calculated isotopic fractionation factors for SO2 photolysis give mass independent distributions that are highly sensitive to the atmospheric concentrations of O2, O3, CO2, H2O, CS2, NH3, N2O, H2S, OCS, and SO2 itself. Various UV-shielding scenarios are considered and we conclude that the negative ?33S observed in the Archean sulfate deposits can only be explained by OCS shielding. Of relevant Archean gases, OCS has the unique ability to prevent SO2 photolysis by sunlight at ? >202 nm. Scenarios run using a photochemical box model show that ppm levels of OCS will accumulate in a CO-rich, reducing Archean atmosphere. The radiative forcing, due to this level of OCS, is able to resolve the faint young sun paradox. Further, the decline of atmospheric OCS may have caused the late Archean glaciation. PMID:19706450

  2. THE OLD ENVIRONMENT OF THE FAINT CALCIUM-RICH SUPERNOVA SN 2005cz

    SciTech Connect

    Perets, Hagai B. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02338 (United States); Gal-yam, Avishay [Weizmann Institute of Science, POB 26, Rehovot (Israel); Crockett, R. Mark; Sullivan, Mark [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Anderson, Joseph P. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); James, Phil A. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Neill, James D. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Leonard, Douglas C. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States)

    2011-02-20

    The supernova SN 2005cz has recently attracted some attention due to the fact that it was spectroscopically similar to type Ib supernovae (SNe Ib), a class that is presumed to result from the core collapse of massive stars, yet it occurred in an elliptical galaxy, where one expects very few massive stars to exist. Two explanations for this remarkable event were put forward. Perets et al. associate SN 2005cz with the class of Ca-rich, faint SNe Ib, which likely result from old double-white-dwarf systems with an He-rich secondary. On the other hand, Kawabata et al. suggest that SN 2005cz is indeed a core-collapse event (in a binary system), albeit of a star at the lower end of the mass range, 10-12 M{sub sun}. The existence of this star in its elliptical host is explained as resulting from low-level star formation (SF) activity in that galaxy. Here we present extensive observations of the location of SN 2005cz, sensitive to a variety of SF tracers, including optical spectroscopy, H{alpha} emission, UV emission, and Hubble Space Telescope photometry. We show that NGC 4589, the host galaxy of SN 2005cz, does not show any signatures of a young stellar population or recent SF activity either close to or far from the location of SN 2005cz.

  3. FAINT TIDAL FEATURES IN GALAXIES WITHIN THE CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY WIDE FIELDS

    SciTech Connect

    Atkinson, Adam M.; Abraham, Roberto G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)] [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Ferguson, Annette M. N. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

    2013-03-01

    We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M{sub r{sup '}}<-19.3 mag) galaxies in the magnitude range 15.5 mag < r' < 17 mag and in the redshift range 0.04 < z < 0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >10{sup 10.5} M {sub Sun }, and red galaxies are twice as likely to show tidal features than are blue galaxies.

  4. First faint dual-field off-axis observations in optical long baseline interferometry

    SciTech Connect

    Woillez, J.; Wizinowich, P.; Ragland, S. [W. M. Keck Observatory, Kamuela, HI 96743 (United States); Akeson, R.; Millan-Gabet, R. [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Colavita, M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Eisner, J. [University of Arizona, Tucson, AZ 85721-0065 (United States); Monnier, J. D. [University of Michigan, Ann Arbor, MI 48109-1090 (United States); Pott, J.-U. [Max-Planck-Institut für Astronomie, Heidelberg, D-69117 (Germany)

    2014-03-10

    Ground-based long baseline interferometers have long been limited in sensitivity in part by the short integration periods imposed by atmospheric turbulence. The first observation fainter than this limit was performed on 2011 January 22 when the Keck Interferometer observed a K = 11.5 target, about 1 mag fainter than its K = 10.3 atmospherically imposed limit; the currently demonstrated limit is K = 12.5. These observations were made possible by the Dual-Field Phase-Referencing (DFPR) instrument, part of the NSF-funded ASTrometry and phase-Referenced Astronomy project; integration times longer than the turbulence time scale are made possible by its ability to simultaneously measure the real-time effects of the atmosphere on a nearby bright guide star and correct for it on the faint target. We present the implementation of DFPR on the Keck Interferometer. Then, we detail its on-sky performance focusing on the accuracy of the turbulence correction and the resulting fringe contrast stability.

  5. A catalog of 7000 optically faint periodic variable stars from the LINEAR survey

    NASA Astrophysics Data System (ADS)

    Ivezic, Zeljko; Palaversa, L.; Sesar, B.; Stuart, J.

    2014-01-01

    We present a catalog of about 7000 optically faint periodic variable stars with light curves obtained by the asteroid survey LINEAR across 10,000 sq.deg. of the northern sky. The majority of these variables have not been cataloged yet. The sample flux limit is several magnitudes fainter than most other wide-angle surveys; the photometric errors range from 0.03 mag at r = 15 to 0.20 mag at r = 18. Light curves include on average 250 data points, collected over about a decade. The sample is dominated by 3900 RR Lyrae stars and 2700 eclipsing binary stars of all subtypes and includes small fractions of relatively rare populations such as asymptotic giant branch stars and SX Phoenicis stars. These publicly available (from https://astroweb.lanl.gov/lineardb/) large samples of robustly classified variable stars will enable detailed statistical studies of the Galactic structure and physics of binary and other stars, and can be used for training automated light curve classification methods. Details about this catalog are available in Palaversa et al. (2013, AJ 146, 101).

  6. McDonald Observatory Solar System Object Astrometry from Wide Field CCD Imaging

    Microsoft Academic Search

    A. L. Whipple; P. J. Shelus; R. W. Whited; A. L. Cochran; P. J. MacQueen; G. F. Benedict

    1995-01-01

    In March 1994 our long standing program of astrometric observations of faint solar system objects at McDonald Observatory moved from a Cassegrain focus photographic plate camera on the 2.1 m telescope to an f\\/3 Prime Focus Corrector (PFC) and CCD system on the 0.76 m telescope. The PFC has an unvignetted 1.1 degree field of view, a flat focal surface

  7. The Infrared Sky

    E-print Network

    E. L. Wright

    2004-09-03

    The infrared sky from space is the sum of a cosmic signal from galaxies, quasars, and perhaps more exotic sources; and foregrounds from the Milky Way and from the Solar System. At a distance of 1 AU from the Sun, the foreground from interplanetary dust is very bright between 5 and 100 microns, but ``very bright'' is still several million times fainter than the background produced by ground-based telescopes. In the near infrared 1-2.2 micron range the space infrared sky is a thousand times fainter than the OH nightglow from the Earth's atmosphere. As a result of these advantages, wide-field imaging from space in the infrared can be an incredibly sensitive method to study the Universe.

  8. Experiment requirements document for reflight of the small helium-cooled infrared telescope experiment

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The four astronomical objectives addressed include: the measurement and mapping of extended low surface brightness infrared emission from the galaxy; the measurement of diffuse emission from intergalactic material and/or galaxies and quasi-stellar objects; the measurement of the zodiacal dust emission; and the measurement of a large number of discrete infrared sources.

  9. Noise analysis of infrared detectors

    Microsoft Academic Search

    Milos Chvatal; V. Sedlakova; J. Majzner

    2009-01-01

    Pyroelectric infrared detectors convert the changes in incoming infrared light to electric signals. Pyroelectric materials are characterized by having spontaneous electric polarization, which is altered by temperature changes as infrared light illuminates the elements. Since our sensor series uses this effect they can be used at ambient temperature even in the presence of thermal noise. By choosing appropriate infrared receiving

  10. Starting Page for Infrared Spectroscopy

    NSDL National Science Digital Library

    Kok ChemWare

    This site is an extensive collection of useful links related to infrared spectroscopy. It features links to resources dealing with the basics of infrared, interpretation of infrared spectra, correlation charts and window material data. From this page, many of the websites available on the internet concerning infrared can be found.

  11. Fourier transform infrared spectroscopy in cancer detection.

    PubMed

    Sahu, R K; Mordechai, S

    2005-10-01

    The rapid developments in the field of infrared spectroscopy in the past decade have demonstrated a potential for disease diagnosis using noninvasive technologies. Several earlier studies have highlighted the advantage of using infrared spectroscopy both in the near- and mid-infrared regions for diagnostic purposes at clinical levels. The areas of focus have been the distinction of premalignant and malignant cells and tissues from their normal state using specific parameters obtained from Fourier transform infrared spectra, making it a rapid and reagent-free method. While it still requires pilot studies and designed clinical trials to ensure the applicability of such systems for cancer diagnosis, substantial progress has been made in incorporating advances in computational methods into the system to increase the sensitivity of the entire setup, making it an objective and sensitive technique suitable for automation to suit the demands of the medical community. The development of fiber-optics systems for infrared spectroscopy have further opened up new and modern avenues in medical diagnosis at various levels of cells, tissues and organs under laboratory and clinical conditions. PMID:16556041

  12. Infrared studies of Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Verdugo Olivares, M. A.; Krisciunas, K.; Suntzeff, N. B.; Phillips, M. M.; Candia, P.

    2002-12-01

    In this project we created an atlas of near-infrared and optical light curves taken from the literature and from our unpublished JHK data of nearby SNe observed at CTIO and LCO. Our objective was to determine whether or not Type Ia supernovae are standardizable candles in the near-infrared. The preliminary conclusions are: a) The morphology of the infrared light curves does not form a simple monotonically changing sequence when organized as a function of evolutionary speed (? m15(B)). Apparently a few SNe which are otherwise normal in the optical seem to have anomalous near-infrared light curves, especially in the J-band. This makes it difficult to construct a single-parameter family of templates that characterize the infrared light curves. However, in general there is a pattern to the these light curves in the sense that the secondary maximum occurs later and more strongly for slower-declining SNe. But, as shown in Krisciunas et al. (2001) for the I-band, there are exceptions to this trend. b) H-band absolute magnitudes 10 days after the time of B-band maximum are essentially constant at -17.91 and not a function of ? m15(B). c) We obtain a Hubble constant of 71.4 +/- 2.5 km s-1 Mpc-1 and a dispersion of +/-0.24 mag in the H-band Hubble diagram. 1CTIO REU/PIA student 2002.

  13. A Search for Exozodiacal Dust and Faint Companions Near Sirius, Procyon, and Altair with the NICMOS Coronagraph

    E-print Network

    Marc J. Kuchner; Michael E. Brown

    2000-02-02

    We observed Sirius, Altair, and Procyon with the NICMOS Coronagraph on the Hubble Space Telescope to look for scattered light from exozodiacal dust and faint companions within 10 AU from these stars. We did not achieve enough dynamic range to surpass the upper limits set by IRAS on the amount of exo-zodiacal dust in these systems, but we did set strong upper limits on the presence of nearby late-type and sub-stellar companions.

  14. CCD uvbybeta photometry of faint stars. III. Metallicities and ages of F-stars in the Galactic disk

    Microsoft Academic Search

    H. Jonch-Sorensen

    1995-01-01

    Stars as faint as V=~22^m^ have been observed in six selected directions of the Galaxy, the limiting magnitude of the sample of stars having the full uvbybeta information is approximately 18.5mag . Intrinsic colours and distances have been derived for 435 F-stars by Jonch-Sorensen (1994b) (Paper II) and in this paper metallicities and effective temperatures are estimated for these stars.

  15. Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy

    Microsoft Academic Search

    N. F. Martin; R. A. Ibata; M. J. Irwin; S. Chapman; G. F. Lewis; A. M. N. Ferguson; N. Tanvir; A. W. McConnachie

    2006-01-01

    We present the discovery of three faint dwarf galaxies and a globular cluster\\u000ain the halo of the Andromeda galaxy (M31), found in our MegaCam survey that\\u000aspans the southern quadrant of M31, from a projected distance of ~50 kpc to\\u000a\\\\~150 kpc. Though the survey covers 57 sq. degrees, the four satellites lie\\u000awithin 2\\\\deg of one another. We

  16. Infrared Fiber Optic Sensors

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Successive years of Small Business Innovation Research (SBIR) contracts from Langley Research Center to Sensiv Inc., a joint venture between Foster-Miller Inc. and Isorad, Ltd., assisted in the creation of remote fiber optic sensing systems. NASA's SBIR interest in infrared, fiber optic sensor technology was geared to monitoring the curing cycles of advanced composite materials. These funds helped in the fabrication of an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. Foster-Miller ingenuity allowed infrared transmitting optical fibers to combine with Fourier Transform Infrared spectroscopy to enable remote sensing. Sensiv probes operate in the mid-infrared range of the spectrum, although modifications to the instrument also permits its use in the near-infrared region. The Sensiv needle-probe is built to be placed in a liquid or powder and analyze the chemicals in the mixture. Other applications of the probe system include food processing control; combustion control in furnaces; and maintenance problem solving.

  17. Infrared Protein Crystallography

    SciTech Connect

    J Sage; Y Zhang; J McGeehan; R Ravelli; M Weik; J van Thor

    2011-12-31

    We consider the application of infrared spectroscopy to protein crystals, with particular emphasis on exploiting molecular orientation through polarization measurements on oriented single crystals. Infrared microscopes enable transmission measurements on individual crystals using either thermal or nonthermal sources, and can accommodate flow cells, used to measure spectral changes induced by exposure to soluble ligands, and cryostreams, used for measurements of flash-cooled crystals. Comparison of unpolarized infrared measurements on crystals and solutions probes the effects of crystallization and can enhance the value of the structural models refined from X-ray diffraction data by establishing solution conditions under which they are most relevant. Results on several proteins are consistent with similar equilibrium conformational distributions in crystal and solutions. However, the rates of conformational change are often perturbed. Infrared measurements also detect products generated by X-ray exposure, including CO{sub 2}. Crystals with favorable symmetry exhibit infrared dichroism that enhances the synergy with X-ray crystallography. Polarized infrared measurements on crystals can distinguish spectral contributions from chemically similar sites, identify hydrogen bonding partners, and, in opportune situations, determine three-dimensional orientations of molecular groups. This article is part of a Special Issue entitled: Protein Structure and Function in the Crystalline State.

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

    NASA Technical Reports Server (NTRS)

    Smith, Howard A.; Allen, L.; Megeath, T.; Barmby, P.; Calvet, N.; Fazio, G.; Hartmann, L.; Myers, P.; Marengo, M.; Gutermuth, R.

    2004-01-01

    The Infrared Array Camera (IRAC) onboard Spitzer has imaged regions of star formation (SF) in its four IR bands with spatial resolutions of approximately 2"/pixel. IRAC is sensitive enough to detect very faint, embedded young stars at levels of tens of Jy, and IRAC photometry can categorize their stages of development: from young protostars with infalling envelopes (Class 0/1) to stars whose infrared excesses derive from accreting circumstellar disks (Class 11) to evolved stars dominated by photospheric emission. The IRAC images also clearly reveal and help diagnose associated regions of shocked and/or PDR emission in the clouds; we find existing models provide a good start at explaining the continuum of the SF regions IRAC observes.

  19. Experimental evaluation of achromatic phase shifters for mid-infrared starlight suppression

    NASA Astrophysics Data System (ADS)

    Gappinger, Robert O.; Diaz, Rosemary T.; Ksendzov, Alexander; Lawson, Peter R.; Lay, Oliver P.; Liewer, Kurt M.; Loya, Frank M.; Martin, Stefan R.; Serabyn, Eugene; Wallace, James K.

    2009-02-01

    Phase shifters are a key component of nulling interferometry, one of the potential routes to enabling the measurement of faint exoplanet spectra. Here, three different achromatic phase shifters are evaluated experimentally in the mid-infrared, where such nulling interferometers may someday operate. The methods evaluated include the use of dispersive glasses, a through-focus field inversion, and field reversals on reflection from antisymmetric flat-mirror periscopes. All three approaches yielded deep, broadband, mid-infrared nulls, but the deepest broadband nulls were obtained with the periscope architecture. In the periscope system, average null depths of 4×10-5 were obtained with a 25% bandwidth, and 2×10-5>/SUP> with a 20% bandwidth, at a central wavelength of 9.5 ?m. The best short term nulls at 20% bandwidth were approximately 9×10-6, in line with error budget predictions and the limits of the current generation of hardware.

  20. Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites

    E-print Network

    Wheeler, Coral; Bullock, James S; Boylan-Kolchin, Michael; Elbert, Oliver; Garrison-Kimmel, Shea; Hopkins, Philip F; Keres, Dusan

    2015-01-01

    We present FIRE/Gizmo hydrodynamic zoom-in simulations of isolated dark matter halos, two each at the mass of classical dwarf galaxies ($M_{\\rm vir} \\simeq 10^{10} M_{\\odot}$) and ultra-faint galaxies ($M_{\\rm vir} \\simeq 10^9 M_{\\odot}$), and with two feedback implementations. The resultant central galaxies lie on an extrapolated abundance matching relation from $M_{\\star} \\simeq 10^6$ to $10^4 M_{\\odot}$ without a break. Every host is filled with subhalos, many of which form stars. Our dwarfs with $M_{\\star} \\simeq 10^6 M_{\\odot}$ each have 1-2 well-resolved satellites with $M_{\\star} = 3-200 \\times 10^3 M_{\\odot}$. Even our isolated ultra-faint galaxies have star-forming subhalos. If this is representative, dwarf galaxies throughout the universe should commonly host tiny satellite galaxies of their own. We combine our results with the ELVIS simulations to show that targeting $\\sim 50~ \\rm kpc$ regions around nearby isolated dwarfs could increase the chances of discovering ultra-faint galaxies by $\\sim 35\\%...