Showing papers by "Simon Dye published in 2009"
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TL;DR: The Herschel ATLAS project as mentioned in this paper is the largest open-time key project that will be carried out on the Herschel Space Observatory, and it will survey 510 square degrees of the extragalactic sky, four times larger than all the other Herschel surveys combined, in five far-infrared and sub-millimetre bands.
Abstract: The Herschel ATLAS is the largest open-time key project that will be carried out on the Herschel Space Observatory. It will survey 510 square degrees of the extragalactic sky, four times larger than all the other Herschel surveys combined, in five far-infrared and submillimetre bands. We describe the survey, the complementary multi-wavelength datasets that will be combined with the Herschel data, and the six major science programmes we are undertaking. Using new models based on a previous submillimetre survey of galaxies, we present predictions of the properties of the ATLAS sources in other wavebands.
579 citations
TL;DR: In this paper, the authors investigate the correlation between far-infrared (FIR) and radio luminosities in distant galaxies, a lynchpin of modern astronomy, using data from the Balloon-borne Large Aperture Submillimetre Telescope (BLAST), Spitzer, the Large Apex BOlometer CamerA (LABOCA), the Very Large Array (VLA) and the Giant Metre-wave Radio Telescope (GMRT) in the Extended Chandra Deep Field South (ECDFS).
Abstract: We investigate the correlation between far-infrared (FIR) and radio luminosities in distant galaxies, a lynchpin of modern astronomy. We use data from the Balloon-borne Large Aperture Submillimetre Telescope (BLAST), Spitzer, the Large Apex BOlometer CamerA (LABOCA), the Very Large Array (VLA) and the Giant Metre-wave Radio Telescope (GMRT) in the Extended Chandra Deep Field South (ECDFS). For a catalogue of BLAST 250-micron-selected galaxies, we re-measure the 70--870-micron flux densities at the positions of their most likely 24-micron counterparts, which have a median [interquartile] redshift of 0.74 [0.25, 1.57]. From these, we determine the monochromatic flux density ratio, q_250 = log_10 (S_250micron / S_1400MHz), and the bolometric equivalent, q_IR. At z ~= 0.6, where our 250-micron filter probes rest-frame 160-micron emission, we find no evolution relative to q_160 for local galaxies. We also stack the FIR and submm images at the positions of 24-micron- and radio-selected galaxies. The difference between q_IR seen for 250-micron- and radio-selected galaxies suggests star formation provides most of the IR luminosity in ~< 100-uJy radio galaxies, but rather less for those in the mJy regime. For the 24-micron sample, the radio spectral index is constant across 0 < z < 3, but q_IR exhibits tentative evidence of a steady decline such that q_IR is proportional to (1+z)^(-0.15 +/- 0.03) - significant evolution, spanning the epoch of galaxy formation, with major implications for techniques that rely on the FIR/radio correlation. We compare with model predictions and speculate that we may be seeing the increase in radio activity that gives rise to the radio background.
143 citations
TL;DR: In this paper, it was shown that the submm emission from Cas A is polarized at a level significantly higher than that of its synchrotron emission, which is consistent with that of the magnetic field in Cas A, implying that the polarization is associated with the supernova remnant.
Abstract: If Type II supernovae – the evolutionary end points of short-lived, massive stars – produce a significant quantity of dust (>0.1 M⊙) then they can explain the rest-frame far-infrared emission seen in galaxies and quasars in the first Gyr of the Universe. Submillimetre (submm) observations of the Galactic supernova remnant, Cas A, provided the first observational evidence for the formation of significant quantities of dust in Type II supernovae. In this paper, we present new data which show that the submm emission from Cas A is polarized at a level significantly higher than that of its synchrotron emission. The orientation is consistent with that of the magnetic field in Cas A, implying that the polarized submm emission is associated with the remnant. No known mechanism would vary the synchrotron polarization in this way and so we attribute the excess polarized submm flux to cold dust within the remnant, providing fresh evidence that cosmic dust can form rapidly. This is supported by the presence of both polarized and unpolarized dust emission in the north of the remnant where there is no contamination from foreground molecular clouds. The inferred dust polarization fraction is unprecedented (fpol∼ 30 per cent) which, coupled with the brief time-scale available for grain alignment (<300 yr), suggests that supernova dust differs from that seen in other Galactic sources (where fpol= 2−7 per cent) or that a highly efficient grain alignment process must operate in the environment of a supernova remnant.
112 citations
TL;DR: In this paper, optical and near-infrared (NIR) spectra were presented for ULAS J131911.4, a new redshift z = 6.127 ± 0.12, just below the signal-to-noise ratio limit of the SDSS high-redshift quasar survey.
Abstract: Optical and near-infrared (NIR) spectra are presented for ULAS J131911.29+095051.4 (hereafter ULAS J1319+0950), a new redshift z = 6.127 ± 0.004 quasar discovered in the Third Data Release (DR3) of the UKIRT Infrared Deep Sky Survey (UKIDSS). The source has YVega = 19.10 ± 0.03, corresponding to M1450,AB = −27.12, which is comparable to the absolute magnitudes of the z � 6 quasars discovered in the Sloan Digital Sky Survey (SDSS). ULAS J1319+0950 was, in fact, registered by SDSS as a faint source with zAB = 20.13 ± 0.12, just below the signal-to-noise ratio limit of the SDSS high-redshift quasar survey. The faint z-band magnitude is a consequence of the weak Ly α/N v emission line, which has a rest-frame equivalent width of ∼20 A and provides only a small boost to the z-band flux. Nevertheless, there is no evidence of a significant new population of high-redshift quasars with weak emission lines from this UKIDSS-based search. The Ly α optical depth to ULAS J1319+0950 is consistent with that measured towards similarly distant SDSS quasars, implying that results from optical- and NIR-selected quasars may be combined in studies of cosmological reionization. Also presented is a new NIR-spectrum of the previously discovered UKIDSS quasar ULAS J020332.38+001229.2, which reveals the object to be a broad absorption line quasar. The new spectrum shows that the emission line initially identified as Ly α is actually N v, leading to a revised redshift of z = 5.72, rather than z = 5.86 as previously estimated.
96 citations
TL;DR: In this article, the authors directly measured the redshift evolution in the mean physical properties (far-infrared luminosity, temperature, and mass) of the galaxies that produce the cosmic infrared background (CIB), using measurements from the Balloon-borne Large Aperture Submillimeter Telescope (BLAST), and Spitzer which constrain the CIB emission peak.
Abstract: We directly measure redshift evolution in the mean physical properties (far-infrared luminosity, temperature, and mass) of the galaxies that produce the cosmic infrared background (CIB), using measurements from the Balloon-borne Large Aperture Submillimeter Telescope (BLAST), and Spitzer which constrain the CIB emission peak. This sample is known to produce a surface brightness in the BLAST bands consistent with the full CIB, and photometric redshifts are identified for all of the objects. We find that most of the 70 μm background is generated at z lsim 1 and the 500 μm background generated at z gsim 1. A significant growth is observed in the mean luminosity from ~109-1012 L sun, and in the mean temperature by 10 K, from redshifts 0 < z < 3. However, there is only weak positive evolution in the comoving dust mass in these galaxies across the same redshift range. We also measure the evolution of the far-infrared luminosity density, and the star formation rate history for these objects, finding good agreement with other infrared studies up to z ~ 1, exceeding the contribution attributed to optically selected galaxies.
88 citations
TL;DR: In this paper, the authors directly measured the redshift evolution in the mean physical properties (far-infrared luminosity, temperature, and mass) of the galaxies that produce the cosmic infrared background (CIB), using measurements from the Balloon-borne Large Aperture Sub-millimeter Telescope (BLAST), and Spitzer which constrain the CIB emission peak.
Abstract: We directly measure redshift evolution in the mean physical properties (far-infrared luminosity, temperature, and mass) of the galaxies that produce the cosmic infrared background (CIB), using measurements from the Balloon-borne Large Aperture Sub-millimeter Telescope (BLAST), and Spitzer which constrain the CIB emission peak. This sample is known to produce a surface brightness in the BLAST bands consistent with the full CIB, and photometric redshifts are identified for all of the objects. We find that most of the 70 micron background is generated at z ~ 1. A significant growth is observed in the mean luminosity from ~ 10^9 - 10^12 L_sun, and in the mean temperature by 10 K, from redshifts 0< z < 3. However, there is only weak positive evolution in the comoving dust mass in these galaxies across the same redshift range. We also measure the evolution of the far-infrared luminosity density, and the star-formation rate history for these objects, finding good agreement with other infrared studies up to z ~1, exceeding the contribution attributed to optically-selected galaxies.
73 citations
TL;DR: In this article, the authors presented the results of a redshift survey in which they succeeded in measuring redshifts for 82 of these counterparts, showing that they are mostly star-forming galaxies but not extreme ones when compared to those found in the Sloan Digital Sky Survey.
Abstract: The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently surveyed sime87 deg2 centered on Great Observatories Origins Deep Survey-South at 250, 350, and 500 μm In Dye et al, we presented the catalog of sources detected at 5σ in at least one band in this field and the probable counterparts to these sources in other wavebands In this paper, we present the results of a redshift survey in which we succeeded in measuring redshifts for 82 of these counterparts The spectra show that the BLAST counterparts are mostly star-forming galaxies but not extreme ones when compared to those found in the Sloan Digital Sky Survey Roughly one quarter of the BLAST counterparts contain an active nucleus We have used the spectroscopic redshifts to carry out a test of the ability of photometric redshift methods to estimate the redshifts of dusty galaxies, showing that the standard methods work well even when a galaxy contains a large amount of dust We have also investigated the cases where there are two possible counterparts to the BLAST source, finding that in at least half of these there is evidence that the two galaxies are physically associated, either because they are interacting or because they are in the same large-scale structure Finally, we have made the first direct measurements of the luminosity function in the three BLAST bands We find strong evolution out to z = 1, in the sense that there is a large increase in the space density of the most luminous galaxies We have also investigated the evolution of the dust-mass function, finding similar strong evolution in the space density of the galaxies with the largest dust masses, showing that the luminosity evolution seen in many wavebands is associated with an increase in the reservoir of interstellar matter in galaxies
56 citations
Cardiff University1, California Institute of Technology2, University of British Columbia3, University of Pennsylvania4, University of Edinburgh5, University of Miami6, National Institute of Astrophysics, Optics and Electronics7, Paris Diderot University8, University of Toronto9, University of Puerto Rico10, University of Paris11, Brown University12
TL;DR: In this paper, radio and/or mid-infrared counterparts to 198 sources detected at ≥5σ over ~9 deg2 centered on the Chandra Deep Field South by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350, and 500 μm.
Abstract: We have identified radio and/or mid-infrared counterparts to 198 out of 350 sources detected at ≥5σ over ~9 deg2 centered on the Chandra Deep Field South by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350, and 500 μm. We have matched 114 of these counterparts to optical sources with previously derived photometric redshifts and fitted spectral energy distributions to the BLAST fluxes and fluxes at 70 and 160 μm acquired with the Spitzer Space Telescope. In this way, we have constrained dust temperatures, total far-infrared/submillimeter luminosities, and star formation rates for each source. Our findings show that, on average, the BLAST sources lie at significantly lower redshifts and have significantly lower rest-frame dust temperatures compared to submillimeter sources detected in surveys conducted at 850 μm. We demonstrate that an apparent increase in dust temperature with redshift in our sample arises as a result of selection effects. Finally, we provide the full multiwavelength catalog of ≥5σ BLAST sources contained within the complete ~9 deg2 survey area.
48 citations
Max Planck Society1, University of St Andrews2, European Southern Observatory3, University of Edinburgh4, University of Nottingham5, University of Sussex6, École Polytechnique Fédérale de Lausanne7, University of Sydney8, University of Portsmouth9, Cardiff University10, Durham University11, Liverpool John Moores University12, Queen Mary University of London13
TL;DR: In this paper, the authors describe the spectroscopic target selection for the Galaxy And Mass Assembly (GAMA) survey and present some of the global statistical properties of the survey, including K-band galaxy counts, colour-redshift relations and preliminary n(z).
Abstract: We describe the spectroscopic target selection for the Galaxy And Mass Assembly (GAMA) survey. The input catalogue is drawn from the Sloan Digital Sky Survey (SDSS) and UKIRT Infrared Deep Sky Survey (UKIDSS). The aim is to measure redshifts for galaxies in three 4x12 degree regions at 9h, 12h and 14.5h, on the celestial equator, with magnitude selections r 0.2. From two years out of a three-year AAOmega program on the Anglo-Australian Telescope, we have obtained 79599 unique galaxy redshifts. Previously known redshifts in the GAMA region bring the total up to 98497. The median galaxy redshift is 0.2 with 99% at z < 0.5. We present some of the global statistical properties of the survey, including K-band galaxy counts, colour-redshift relations and preliminary n(z).
15 citations
Posted Content•
Kapteyn Astronomical Institute1, University of California, Santa Barbara2, Stanford University3, Index Fund Advisors4, California Institute of Technology5, Cardiff University6, University of California, Santa Cruz7, Princeton University8, University of California, Davis9, Rutgers University10, ASTRON11, Institute for Advanced Study12, University of St Andrews13
TL;DR: In this paper, a staged approach with radio (e.g., EVLA, e-MERLIN, LOFAR, SKA phase-I) and optical (i.e., LSST and JDEM) instruments can provide 10^(2-4) new lenses, and up to 10^ (4-6) new lens systems from SKA/LSST/JDEM all-sky surveys around ~2020.
Abstract: Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still ill-defined. Strong gravitational lensing furnishes a powerful method to probe gravity in the central regions of galaxies. It can (1) provide a unique detection-channel of dark-matter substructure beyond the local galaxy group, (2) constrain dark-matter physics, complementary to direct-detection experiments, as well as metric theories of gravity, (3) probe central super-massive black holes, and (4) provide crucial insight into galaxy formation processes from the dark matter point of view, independently of the nature and state of dark matter. To seriously address the above questions, a considerable increase in the number of strong gravitational-lens systems is required. In the timeframe 2010-2020, a staged approach with radio (e.g. EVLA, e-MERLIN, LOFAR, SKA phase-I) and optical (e.g. LSST and JDEM) instruments can provide 10^(2-4) new lenses, and up to 10^(4-6) new lens systems from SKA/LSST/JDEM all-sky surveys around ~2020. Follow-up imaging of (radio) lenses is necessary with moderate ground/space-based optical-IR telescopes and with 30-50m telescopes for spectroscopy (e.g. TMT, GMT, ELT). To answer these fundamental questions through strong gravitational lensing, a strong investment in large radio and optical-IR facilities is therefore critical in the coming decade. In particular, only large-scale radio lens surveys (e.g. with SKA) provide the large numbers of high-resolution and high-fidelity images of lenses needed for SMBH and flux-ratio anomaly studies.
8 citations
Journal Article•
TL;DR: In this article, the authors presented constraints on the nature of the first galaxies selected at 350 micrometers, including galaxies discovered in the deepest blank-field survey at 1 < z < 3 and also later serendipitous detections in the Lockman Hole.
Abstract: We present constraints on the nature of the first galaxies selected at 350 micrometers. The sample includes galaxies discovered in the deepest blank-field survey at 350 micrometers (in the Bo6tes Deep Field) and also later serendipitous detections in the Lockman Hole. In determining multiwavelength identifications, the 350 lam position and map resolution of the second generation Submillimeter High Angular Resolution Camera are critical, especially in the cases where multiple radio sources exist and the 24 micrometer counterparts are unresolved. Spectral energy distribution templates are fitted to identified counterparts, and the sample is found to comprise IR-luminous galaxies at 1 < z < 3 predominantly powered by star formation. The first spectrum of a 350 micrometer selected galaxy provides an additional confirmation, showing prominent dust grain features typically associated with star-forming galaxies. Compared to submillimeter galaxies selected at 850 and 1100 micrometers, galaxies selected at 350 micrometers have a similar range of far-infrared color temperatures. However, no 350 micrometer selected sources are reliably detected at 850 or 1100 micrometers. Galaxies in our sample with redshifts 1 < z < 2 show a tight correlation between the far- and mid-infrared flux densities, but galaxies at higher redshifts show a large dispersion in their mid- to far-infrared colors. This implies a limit to which the mid-IR emission traces the far-IR emission in star-forming galaxies. The 350 micrometer flux densities (15 < S(sub 350) < 40 mJy) place these objects near the Herschel/SPIRE 350 micrometer confusion threshold, with the lower limit on the star formation rate density suggesting the bulk of the 350 micrometers contribution will come from less luminous infrared sources and normal galaxies. Therefore, the nature of the dominant source of the 350 micrometers background-star-forming galaxies in the epoch of peak star formation in the universe-could be more effectively probed using ground-based instruments with their angular resolution and sensitivity offering significant advantages over space-based imaging. Key words: galaxies: high-redshift galaxies: starburst infrared: galaxies submillimeter
Cardiff University1, California Institute of Technology2, University of British Columbia3, University of Pennsylvania4, University of Edinburgh5, University of Miami6, National Institute of Astrophysics, Optics and Electronics7, Paris Diderot University8, University of Toronto9, University of Puerto Rico10, University of Paris11, Brown University12
TL;DR: In this paper, radio and/or mid-infrared counterparts to 198 sources detected at >=5 sigma over 9 square degrees centered on the Chandra Deep Field South (CDFS) by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350 and 500 um.
Abstract: We have identified radio and/or mid-infrared counterparts to 198 out of 350 sources detected at >=5 sigma over ~ 9 square degrees centered on the Chandra Deep Field South (CDFS) by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350 and 500 um. We have matched 114 of these counterparts to optical sources with previously derived photometric redshifts and fitted SEDs to the BLAST fluxes and fluxes at 70 and 160 um acquired with the Spitzer Space Telescope. In this way, we have constrained dust temperatures, total far-infrared/sub-millimeter luminosities and star formation rates for each source. Our findings show that on average, the BLAST sources lie at significantly lower redshifts and have significantly lower rest-frame dust temperatures compared to submm sources detected in surveys conducted at 850 um. We demonstrate that an apparent increase in dust temperature with redshift in our sample arises as a result of selection effects. Finally, we provide the full multi-wavelength catalog of >= 5 sigma BLAST sources contained within the complete ~ 9 square degree survey area.
University of Colorado Boulder1, University of Massachusetts Amherst2, University of Edinburgh3, University of British Columbia4, National Institute of Astrophysics, Optics and Electronics5, University of Nottingham6, University of Cambridge7, Imperial College London8, Durham University9, Cardiff University10, University of Arizona11, Cornell University12, University of Sussex13, European Southern Observatory14, Sejong University15, Smith College16, Open University17, University of Oxford18, University of Hertfordshire19, National Radio Astronomy Observatory20
TL;DR: The first results from the largest deep extragalactic millimetre-wavelength survey undertaken to date were derived from maps covering over 0.7 deg^2, made at 1.1mm using the AzTEC continuum camera mounted on the James Clerk Maxwell Telescope as discussed by the authors.
Abstract: We present the first results from the largest deep extragalactic millimetre-wavelength survey undertaken to date. These results are derived from maps covering over 0.7 deg^2, made at 1.1mm, using the AzTEC continuum camera mounted on the James Clerk Maxwell Telescope. The maps were made in the two fields originally targeted at 0.85mm with SCUBA in the SHADES project, namely the Lockman Hole East (mapped to a depth of 0.9-1.3 mJy rms) and the Subaru XMM Deep Field (1.0-1.7 mJy rms). The wealth of existing and forthcoming deep multi-frequency data in these two fields will allow the bright mm source population revealed by these images to be explored in detail in subsequent papers. Here we present the maps themselves, a catalogue of 114 high-significance sub-millimetre galaxy detections, and a thorough statistical analysis leading to the most robust determination to date of the 1.1mm source number counts. Through careful comparison, we find that both the COSMOS and GOODS North fields, also imaged with AzTEC, contain an excess of mm sources over the new 1.1mm source-count baseline established here. In particular, our new AzTEC/SHADES results indicate that very luminous high-redshift dust enshrouded starbursts (S_{1.1} > 3 mJy) are 25-50% less common than would have been inferred from these smaller surveys, thus highlighting the potential roles of cosmic variance and clustering in such measurements. We compare number count predictions from recent models of the evolving mm/sub-mm source population to these SMG surveys, which provide important constraints for the ongoing refinement of semi-analytic and hydrodynamical models of galaxy formation, and find that all recent models over-predict the number of bright sub-millimetre galaxies found in this survey.
TL;DR: In this paper, the authors presented constraints on the nature of the first galaxies selected at 350 microns, including galaxies discovered in the Bootes Deep Field and also later serendipitous detections in the Lockman Hole.
Abstract: [abridged] We present constraints on the nature of the first galaxies selected at 350 microns. The sample includes galaxies discovered in the deepest blank-field survey at 350 microns (in the Bootes Deep Field) and also later serendipitous detections in the Lockman Hole. Spectral energy distribution templates are fit to identified counterparts, and the sample is found to comprise IR-luminous galaxies at 1
Imperial College London1, Harvard University2, University of Lethbridge3, Rutherford Appleton Laboratory4, Goddard Space Flight Center5, Cardiff University6, University of Sussex7, Cornell University8, Shanghai Normal University9, University of Hawaii10, University of Padua11, Open University12, University of Maryland, College Park13
TL;DR: In this paper, the authors presented constraints on the nature of the first galaxies selected at 350 μm and found that the majority of the galaxies at the Herschel/SPIRE 350 µm confusion threshold are star-forming galaxies.
Abstract: We present constraints on the nature of the first galaxies selected at 350 μm. The sample includes galaxies discovered in the deepest blank-field survey at 350 μm (in the Bootes Deep Field) and also later serendipitous detections in the Lockman Hole. In determining multiwavelength identifications, the 350 μm position and map resolution of the second generation Submillimeter High Angular Resolution Camera are critical, especially in the cases where multiple radio sources exist and the 24 μm counterparts are unresolved. Spectral energy distribution templates are fitted to identified counterparts, and the sample is found to comprise IR-luminous galaxies at 1 < z < 3 predominantly powered by star formation. The first spectrum of a 350 μm selected galaxy provides an additional confirmation, showing prominent dust grain features typically associated with star-forming galaxies. Compared to submillimeter galaxies selected at 850 and 1100 μm, galaxies selected at 350 μm have a similar range of far-infrared color temperatures. However, no 350 μm selected sources are reliably detected at 850 or 1100 μm. Galaxies in our sample with redshifts 1 < z < 2 show a tight correlation between the far- and mid-infrared flux densities, but galaxies at higher redshifts show a large dispersion in their mid- to far-infrared colors. This implies a limit to which the mid-IR emission traces the far-IR emission in star-forming galaxies. The 350 μm flux densities (15 < S 350 < 40 mJy) place these objects near the Herschel/SPIRE 350 μm confusion threshold, with the lower limit on the star formation rate density suggesting the bulk of the 350 μm contribution will come from less luminous infrared sources and normal galaxies. Therefore, the nature of the dominant source of the 350 μm background—star-forming galaxies in the epoch of peak star formation in the universe—could be more effectively probed using ground-based instruments with their angular resolution and sensitivity offering significant advantages over space-based imaging.
01 Jan 2009
TL;DR: In this article, a staged approach with radio (e-MERLIN, LOFAR, SKA phase-I) and optical (e.g., LSST and JDEM) instruments is proposed.
Abstract: Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, supermassive black holes, and (metric) theories of gravity, is still ill-defined. Strong gravitational lensing furnishes a powerful method to probe gravity in the central regions of galaxies. It can (1) provide a unique detection-channel of dark-matter substructure beyond the local galaxy group, (2) constrain dark-matter physics, complementary to direct-detection experiments, as well as metric theories of gravity, (3) probe central supermassive black holes, and (4) provide crucial insight into galaxy formation processes from the dark matter point of view, independently of the nature and state of dark matter. To seriously address the above questions, a considerable increase in the number of strong gravitational-lens systems is required. In the timeframe 2010-2020, a staged approach with radio (e.g. EVLA, e-MERLIN, LOFAR, SKA phase-I) and optical (e.g. LSST and JDEM) instruments can provide 10
TL;DR: In this paper, the results of a redshift survey of the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) have been presented, in which they succeeded in measuring redshifts for 82 of these counterparts, showing that these are mostly star-forming galaxies but not extreme ones when compared to those found in the Sloan Digital Sky Survey.
Abstract: The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently surveyed ~8.7 deg^2 centered on GOODS-South at 250, 350, and 500 microns. In Dye et al. (2009) we presented the catalogue of sources detected at 5-sigma in at least one band in this field and the probable counterparts to these sources in other wavebands. In this paper, we present the results of a redshift survey in which we succeeded in measuring redshifts for 82 of these counterparts. The spectra show that the BLAST counterparts are mostly star-forming galaxies but not extreme ones when compared to those found in the Sloan Digital Sky Survey. Roughly one quarter of the BLAST counterparts contain an active nucleus. We have used the spectroscopic redshifts to carry out a test of the ability of photometric redshift methods to estimate the redshifts of dusty galaxies, showing that the standard methods work well even when a galaxy contains a large amount of dust. We have also investigated the cases where there are two possible counterparts to the BLAST source, finding that in at least half of these there is evidence that the two galaxies are physically associated, either because they are interacting or because they are in the same large-scale structure. Finally, we have made the first direct measurements of the luminosity function in the three BLAST bands. We find strong evolution out to z=1, in the sense that there is a large increase in the space-density of the most luminous galaxies. We have also investigated the evolution of the dust-mass function, finding similar strong evolution in the space-density of the galaxies with the largest dust masses, showing that the luminosity evolution seen in many wavebands is associated with an increase in the reservoir of interstellar matter in galaxies.
01 Jan 2009
TL;DR: In this article, radio and/or mid-infrared counterparts to 198 sources detected at ≥ 5� over ∼ 9 deg 2 centered on the Chandra Deep Field South (CDFS) by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350 and 500 µm.
Abstract: We have identified radio and/or mid-infrared counterparts to 198 out of 350 sources detected at ≥ 5� over ∼ 9 deg 2 centered on the Chandra Deep Field South (CDFS) by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350 and 500 µm. We have matched 114 of these counterparts to optical sources with previously derived photometric redshifts and fitted SEDs to the BLAST fluxes and fluxes at 70 and 160 µm acquired with the Spitzer Space Telescope. In this way, we have constrained dust temperatures, total far-infrared/sub-millimeter luminosities and star formation rates for each source. Our findings show that on average, the BLAST sources lie at significantly lower redshifts and have significantly lower rest-frame dust temperatures compared to submm sources detected in surveys conducted at 850 µm. We demonstrate that an apparent increase in dust temperature with redshift in our sample arises as a result of selection effects. Finally, we provide the full multi-wavelength catalog of ≥ 5� BLAST sources contained within the complete ∼ 9 deg 2 survey area. Subject headings: Submillimeter - surveys - cosmology: observations - galaxies: high-redshift - infrared: galaxies