-
Arabindo Roy,
Peter A. R. Ade,
James J. Bock,
Christopher M. Brunt,
Edward L. Chapin,
Mark J. Devlin,
Simon R. Dicker,
Kevin France,
Andrew G. Gibb,
Matthew Griffin, [......],
Luca Olmi,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
and Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present an implementation of the iterative flux-conserving Lucy-Richardson (L-R) deconvolution method of image restoration for maps produced by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Compared to the direct Fourier transform method of deconvolution, the L-R operation restores images with better-controlled background noise and increases source detectability. Intermediate iterated images are useful for studying extended diffuse structures, while the later iterations truly enhance point sources to near the designed diffraction limit of the telescope. The L-R method of deconvolution is efficient in resolving compact sources in crowded regions while simultaneously conserving their respective flux densities. We have analyzed its performance and convergence extensively through simulations and cross-correlations of the deconvolved images with available high-resolution maps. We present new science results from two BLAST surveys, in the Galactic regions K3-50 and IC 5146, further demonstrating the benefits of performing this deconvolution. We have resolved three clumps within a radius of 45 inside the star-forming molecular cloud containing K3-50. Combining the well-resolved dust emission map with available multi-wavelength data, we have constrained the spectral energy distributions (SEDs) of five clumps to obtain masses (M), bolometric luminosities (L), and dust temperatures (T). The L-M diagram has been used as a diagnostic tool to estimate the evolutionary stages of the clumps. There are close relationships between dust continuum emission and both 21 cm radio continuum and 12CO molecular line emission. The restored extended large-scale structures in the Northern Streamer of IC 5146 have a strong spatial correlation with both SCUBA and high-resolution extinction images. A dust temperature of 12 K has been obtained for the central filament. We report physical properties of ten compact sources, including six associated protostars, by fitting SEDs to multi-wavelength data. All of these compact sources are still quite cold (typical temperature below ~ 16 K) and are above the critical Bonner-Ebert mass. They have associated low-power young stellar objects. Further evidence for starless clumps has also been found in the IC 5146 region.
The Astrophysical Journal 03/2011; 730(2):142. · 6.02 Impact Factor
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Elisabetta Valiante,
Peter A. R. Ade,
James J. Bock,
Filiberto G. Braglia,
Edward L. Chapin,
Mark J. Devlin,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Douglas Scott,
Kimberly Scott,
Christopher Semisch,
Hans Stabenau,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
and Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present results from a survey carried out by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) on a 9 deg2 field near the South Ecliptic Pole at 250, 350, and 500 μm. The median 1σ depths of the maps are 36.0, 26.4, and 18.4 mJy, respectively. We apply a statistical method to estimate submillimeter galaxy number counts and find that they are in agreement with other measurements made with the same instrument and with the more recent results from Herschel/SPIRE. Thanks to the large field observed, the new measurements give additional constraints on the bright end of the counts. We identify 132, 89, and 61 sources with S/N ≥4 at 250, 350, 500 μm, respectively and provide a multi-wavelength combined catalog of 232 sources with a significance ≥4σ in at least one BLAST band. The new BLAST maps and catalogs are available publicly at http://blastexperiment.info.
The Astrophysical Journal Supplement Series 11/2010; 191(2):222. · 13.46 Impact Factor
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Alana Rivera-Ingraham,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon R. Dicker,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Luca Olmi,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
and Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We have carried out the first general submillimeter analysis of the field toward GRSMC 45.46+0.05, a massive star-forming region in Aquila. The deconvolved 6 deg2 (3° × 2°) maps provided by BLAST in 2005 at 250, 350, and 500 μm were used to perform a preliminary characterization of the clump population previously investigated in the infrared, radio, and molecular maps. Interferometric CORNISH data at 4.8 GHz have also been used to characterize the Ultracompact H II regions (UCHIIRs) within the main clumps. By means of the BLAST maps, we have produced an initial census of the submillimeter structures that will be observed by Herschel, several of which are known Infrared Dark Clouds. Our spectral energy distributions of the main clumps in the field, located at ~7 kpc, reveal an active population with temperatures of T~ 35-40 K and masses of ~103 M ☉ for a dust emissivity index β = 1.5. The clump evolutionary stages range from evolved sources, with extended H II regions and prominent IR stellar population, to massive young stellar objects, prior to the formation of an UCHIIR. The CORNISH data have revealed the details of the stellar content and structure of the UCHIIRs. In most cases, the ionizing stars corresponding to the brightest radio detections are capable of accounting for the clump bolometric luminosity, in most cases powered by embedded OB stellar clusters.
The Astrophysical Journal 10/2010; 723(1):915. · 6.02 Impact Factor
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Arabindo Roy,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon R. Dicker,
Kevin France,
Andrew G. Gibb,
Matthew Griffin,
Joshua O. Gundersen, [......],
Luca Olmi,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present Cygnus X in a new multi-wavelength perspective based on an unbiased BLAST survey at 250, 350, and 500 {\mu}m, combined with rich datasets for this well-studied region. To interpret the BLAST emission more fully and place the compact sources in context, we make use of archival data cubes of 13CO line emission from KOSMA, MIPS images from the Spitzer Legacy Survey of this region, and 21-cm radio continuum maps from the Canadian Galactic Plane Survey (CGPS). Our primary goal is to investigate the early stages of high mass star formation. We have detected 184 compact sources in various stages of evolution across all three BLAST bands. From their spectral energy distributions, now well constrained by the broad spectral coverage, we obtain the physical properties mass (M), bolometric luminosity (L), and dust temperature (T). Some of the bright sources with T reaching 40 K contain well-known compact H II regions, like W75N, DR21, and AFGL2591. We relate these to other sources at earlier stages of evolution via the energetics as deduced from their position in the L -M diagram. The submillimeter spectral coverage of the BLAST bands, near the peak of the spectral energy distribution of the dust, reveals fainter sources too cool (down to T ~ 10 K) to be seen by earlier shorter-wavelength surveys like IRAS. We detect thermal emission from infrared dark clouds and investigate the phenomenon of cold "starless cores" more generally. When examined in Spitzer 24 or 8 {\mu}m images, these cold sources often show stellar nurseries. Although they are potential sites for massive star formation, they are "starless" in the sense that to date there is no massive protostar in a vigorous accretion phase. Comment: 38 pages, 27 figures, 5 tables
09/2010;
-
Alana Rivera-Ingraham,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon R. Dicker,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Guillaume Patanchon, Marie Rex,
Arabindo Roy,
Douglas Scott,
Christopher Semisch,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We have carried out the first general submillimeter analysis of the field
towards GRSMC 45.46+0.05, a massive star forming region in Aquila. The
deconvolved 6 deg^2 (3\degree X 2\degree) maps provided by BLAST in 2005 at
250, 350, and 500 micron were used to perform a preliminary characterization of
the clump population previously investigated in the infrared, radio, and
molecular maps. Interferometric CORNISH data at 4.8 GHz have also been used to
characterize the Ultracompact HII regions (UCHIIRs) within the main clumps. By
means of the BLAST maps we have produced an initial census of the submillimeter
structures that will be observed by Herschel, several of which are known
Infrared Dark Clouds (IRDCs). Our spectral energy distributions of the main
clumps in the field, located at ~7 kpc, reveal an active population with
temperatures of T~35-40 K and masses of ~10^3 Msun for a dust emissivity index
beta=1.5. The clump evolutionary stages range from evolved sources, with
extended HII regions and prominent IR stellar population, to massive young
stellar objects, prior to the formation of an UCHIIR.The CORNISH data have
revealed the details of the stellar content and structure of the UCHIIRs. In
most cases, the ionizing stars corresponding to the brightest radio detections
are capable of accounting for the clump bolometric luminosity, in most cases
powered by embedded OB stellar clusters.
09/2010;
-
Marco P. Viero,
Lorenzo Moncelsi,
Erin Mentuch,
Fernando Buitrago,
Amanda E. Bauer,
Edward L. Chapin,
Christopher J. Conselice,
Mark J. Devlin,
Mark Halpern,
Gaelen Marsden,
Calvin B. Netterfield,
Enzo Pascale,
Pablo. G. Pérez-González, Marie Rex,
Douglas Scott,
Matthew W. L. Smith,
Matthew D. P. Truch,
Ignacio Trujillo,
Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present measurements of the mean mid-infrared-to-submillimeter flux
densities of massive (M\ast \approx 2 \times 10^11 Msun) galaxies at redshifts
1.7 < z < 2.9, obtained by stacking positions of known objects taken from the
GOODS NICMOS Survey (GNS) catalog on maps: at 24 {\mu}m (Spitzer/MIPS); 70,
100, and 160{\mu}m (Herschel/PACS); 250, 350, 500{\mu}m (BLAST); and 870{\mu}m
(LABOCA). A modified blackbody spectrum fit to the stacked flux densities
indicates a median [interquartile] star-formation rate of SFR = 63 [48, 81]
Msun yr^-1 . We note that not properly accounting for correlations between
bands when fitting stacked data can significantly bias the result. The galaxies
are divided into two groups, disk-like and spheroid-like, according to their
Sersic indices, n. We find evidence that most of the star formation is
occurring in n \leq 2 (disk-like) galaxies, with median [interquartile] SFR =
122 [100,150] Msun yr^-1, while there are indications that the n > 2
(spheroid-like) population may be forming stars at a median [interquartile] SFR
= 14 [9,20] Msun yr^-1, if at all. Finally, we show that star formation is a
plausible mechanism for size evolution in this population as a whole, but find
only marginal evidence that it is what drives the expansion of the
spheroid-like galaxies.
08/2010;
-
Elisabetta Valiante,
Peter Ade,
James Bock,
Filiberto Braglia,
Edward Chapin,
Mark Joseph Devlin,
Matthew Griffin,
Joshua Gundersen,
Mark Halpern,
Peter Hargrave, [......],
Douglas Scott,
Kimberly Scott,
Christopher Semisch,
Hans Stabenau,
Nicholas Thomas,
Matthew Truch,
Carole Tucker,
Gregory Tucker,
Marco Viero,
Donald Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present results from a survey carried out by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) on a 9 deg^2 field near the South Ecliptic Pole at 250, 350 and 500 {\mu}m. The median 1{\sigma} depths of the maps are 36.0, 26.4 and 18.4 mJy, respectively. We apply a statistical method to estimate submillimeter galaxy number counts and find that they are in agreement with other measurements made with the same instrument and with the more recent results from Herschel/SPIRE. Thanks to the large field observed, the new measurements give additional constraints on the bright end of the counts. We identify 132, 89 and 61 sources with S/N>4 at 250, 350, 500 {\mu}m, respectively and provide a multi-wavelength combined catalog of 232 sources with a significance >4{\sigma} in at least one BLAST band. The new BLAST maps and catalogs are available publicly at http://blastexperiment.info. Comment: 25 pages, 6 figures, 4 tables, Accepted by ApJS. Maps and catalogs available at http://blastexperiment.info/
07/2010;
-
Filiberto G. Braglia,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Alastair Edge,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......], Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Elisabetta Valiante,
Marco P. Viero,
Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present observations at 250, 350, and 500 um of the nearby galaxy cluster Abell 3112 (z=0.075) carried out with BLAST, the Balloon-borne Large Aperture Submillimeter Telescope. Five cluster members are individually detected as bright submillimetre sources. Their far-infrared SEDs and optical colours identify them as normal star-forming galaxies of high mass, with globally evolved stellar populations. They all have B-R colours of 1.38+/-0.08, transitional between the blue, active population and the red, evolved galaxies that dominate the cluster core. We stack to determine the mean submillimetre emission from all cluster members, which is determined to be 16.6+/-2.5, 6.1+/-1.9, and 1.5+/-1.3 mJy at 250, 350, and 500 um, respectively. Stacking analyses of the submillimetre emission of cluster members reveal trends in the mean far-infrared luminosity with respect to cluster-centric radius and Ks-band magnitude. We find that a large fraction of submillimetre emission comes from the boundary of the inner, virialized region of the cluster, at cluster-centric distances around R_500. Stacking also shows that the bulk of the submillimetre emission arises in intermediate-mass galaxies (L<L*), with Ks magnitude ~1 mag fainter than the giant ellipticals. The results and constraints obtained in this work will provide a useful reference for the forthcoming surveys to be conducted on galaxy clusters by Herschel. Comment: 17 pages, 7 figures; submitted to MNRAS. Maps and related data are available at http://blastexperiment.info
03/2010;
-
R. J. Ivison,
David M. Alexander,
Andy D. Biggs,
W. N. Brandt,
Edward L. Chapin,
Kristen E. K. Coppin,
Mark J. Devlin,
Mark Dickinson,
James Dunlop,
Simon Dye, [......],
C. Semisch,
Ian Smail,
A. M. Swinbank,
Matthew D. P. Truch,
Gregory S. Tucker,
Marco P. Viero,
Fabian Walter,
Axel Weiß,
Donald V. Wiebe,
Y. Q. Xue
[show abstract]
[hide abstract]
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 and the Giant Metre-wave Radio Telescope (GMRT) in the Extended Chandra Deep Field South (ECDFS). For a catalogue of BLAST 250-μm-selected galaxies, we remeasure the 70–870-μm flux densities at the positions of their most likely 24-μm counterparts, which have a median [interquartile] redshift of 0.74 [0.25, 1.57]. From these, we determine the monochromatic flux density ratio, q250(= log10[S250 μm/S1400 MHz]), and the bolometric equivalent, qIR. At z≈ 0.6, where our 250-μm filter probes rest-frame 160-μm emission, we find no evolution relative to q160 for local galaxies. We also stack the FIR and submm images at the positions of 24-μm- and radio-selected galaxies. The difference between qIR seen for 250-μm- and radio-selected galaxies suggests that star formation provides most of the IR luminosity in ≲100-μJy radio galaxies, but rather less for those in the mJy regime. For the 24-μm sample, the radio spectral index is constant across 0 < z < 3, but qIR exhibits tentative evidence of a steady decline such that qIR∝ (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.
Monthly Notices of the Royal Astronomical Society 02/2010; 402(1):245 - 258. · 4.90 Impact Factor
-
Marco P. Viero,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave,
David H. Hughes, [......],
Enzo Pascale,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
and Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We detect correlations in the cosmic far-infrared background due to the clustering of star-forming galaxies in observations made with the Balloon-borne Large Aperture Submillimeter Telescope, at 250, 350, and 500 μm. We perform jackknife and other tests to confirm the reality of the signal. The measured correlations are well fitted by a power law over scales of 5'-25', with ΔI/I = 15.1% ± 1.7%. We adopt a specific model for submillimeter sources in which the contribution to clustering comes from sources in the redshift ranges 1.3 ≤ z ≤ 2.2, 1.5 ≤ z ≤ 2.7, and 1.7 ≤ z ≤ 3.2, at 250, 350, and 500 μm, respectively. With these distributions, our measurement of the power spectrum, P(k θ), corresponds to linear bias parameters, b = 3.8 ± 0.6, 3.9 ± 0.6, and 4.4 ± 0.7, respectively. We further interpret the results in terms of the halo model, and find that at the smaller scales, the simplest halo model fails to fit our results. One way to improve the fit is to increase the radius at which dark matter halos are artificially truncated in the model, which is equivalent to having some star-forming galaxies at z ≥ 1 located in the outskirts of groups and clusters. In the context of this model, we find a minimum halo mass required to host a galaxy is log(M min/M ☉) = 11.5+0.4 –0.1, and we derive effective biases b eff = 2.2 ± 0.2, 2.4 ± 0.2, and 2.6 ± 0.2, and effective masses , 12.8 ± 0.2, and 12.7 ± 0.2, at 250, 350 and 500 μm, corresponding to spatial correlation lengths of r 0 = 4.9, 5.0, and , respectively. Finally, we discuss implications for clustering measurement strategies with Herschel and Planck.
The Astrophysical Journal 12/2009; 707(2):1766. · 6.02 Impact Factor
-
Calvin B. Netterfield,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave,
David H. Hughes, [......], Marie Rex,
Arabindo Roy,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
and Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present first results from an unbiased 50 deg2 submillimeter Galactic survey at 250, 350, and 500 μm from the 2006 flight of the Balloon-borne Large Aperture Submillimeter Telescope. The map has resolution ranging from 36'' to 60'' in the three submillimeter bands spanning the thermal emission peak of cold starless cores. We determine the temperature, luminosity, and mass of more than 1000 compact sources in a range of evolutionary stages and an unbiased statistical characterization of the population. From comparison with C18O data, we find the dust opacity per gas mass, κr= 0.16 cm2 g–1 at 250 μm, for cold clumps. We find that 2% of the mass of the molecular gas over this diverse region is in cores colder than 14 K, and that the mass function for these cold cores is consistent with a power law with index α = –3.22 ± 0.14 over the mass range 14 M ☉ < M < 80 M ☉. Additionally, we infer a mass-dependent cold core lifetime of tc (M) = 4 × 106(M/20 M ☉)–0.9 yr—longer than what has been found in previous surveys of either low or high-mass cores, and significantly longer than free fall or likely turbulent decay times. This implies some form of non-thermal support for cold cores during this early stage of star formation.
The Astrophysical Journal 12/2009; 707(2):1824. · 6.02 Impact Factor
-
Matthew D. P. Truch,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon R. Dicker,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Enzo Pascale,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas E. Thomas,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
and Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 250 hr flight over Antarctica in 2006 December (BLAST06). As part of the calibration and pointing procedures, the red hypergiant star VY CMa was observed and used as the primary calibrator. Details of the overall BLAST06 calibration procedure are discussed. The 1σ uncertainty on the absolute calibration is accurate to 9.5%, 8.7%, and 9.2% at the 250, 350, and 500 μm bands, respectively. The errors are highly correlated between bands resulting in much lower errors for the derived shape of the 250-500 μm continuum. The overall pointing error is < 5'' rms for the 36'', 42'', and 60'' beams. The performance of optics and pointing systems is discussed.
The Astrophysical Journal 12/2009; 707(2):1723. · 6.02 Impact Factor
-
Donald V. Wiebe,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon Dicker,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Enzo Pascale,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero
[show abstract]
[hide abstract]
ABSTRACT: Over the course of two flights, the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) made resolved maps of seven nearby (<25 Mpc) galaxies at 250, 350, and 500 μm. During its 2005 June flight from Sweden, BLAST observed a single nearby galaxy, NGC 4565. During the 2006 December flight from Antarctica, BLAST observed the nearby galaxies NGC 1097, NGC 1291, NGC 1365, NGC 1512, NGC 1566, and NGC 1808. We fit physical dust models to a combination of BLAST observations and other available data for the galaxies observed by Spitzer. We fit a modified blackbody to the remaining galaxies to obtain total dust mass and mean dust temperature. For the four galaxies with Spitzer data, we also produce maps and radial profiles of dust column density and temperature. We measure the fraction of BLAST detected flux originating from the central cores of these galaxies and use this to calculate a "core fraction," an upper limit on the "active galactic nucleus fraction" of these galaxies. We also find our resolved observations of these galaxies give a dust mass estimate 5-19 times larger than an unresolved observation would predict. Finally, we are able to use these data to derive a value for the dust mass absorption coefficient of κ = 0.29 ± 0.03 m^2 kg^(–1) at 250 μm. This study is an introduction to future higher-resolution and higher-sensitivity studies to be conducted by Herschel and SCUBA-2.
The Astrophysical Journal 12/2009; · 6.02 Impact Factor
-
Calvin B. Netterfield,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave,
David H. Hughes, [......], Marie Rex,
Arabindo Roy,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: We present first results from an unbiased 50 deg2
submillimeter Galactic survey at 250, 350, and 500 μm from the 2006
flight of the Balloon-borne Large Aperture Submillimeter Telescope. The
map has resolution ranging from 36'' to 60'' in the three submillimeter
bands spanning the thermal emission peak of cold starless cores. We
determine the temperature, luminosity, and mass of more than 1000
compact sources in a range of evolutionary stages and an unbiased
statistical characterization of the population. From comparison with
C18O data, we find the dust opacity per gas mass, κr=
0.16 cm2 g-1 at 250 μm, for cold clumps. We
find that 2% of the mass of the molecular gas over this diverse region
is in cores colder than 14 K, and that the mass function for these cold
cores is consistent with a power law with index α = -3.22 ±
0.14 over the mass range 14 M sun < M < 80 M
sun. Additionally, we infer a mass-dependent cold core
lifetime of tc (M) = 4 × 106(M/20 M
sun)-0.9 yr—longer than what has been found
in previous surveys of either low or high-mass cores, and significantly
longer than free fall or likely turbulent decay times. This implies some
form of non-thermal support for cold cores during this early stage of
star formation.
The Astrophysical Journal 11/2009; 707:1824-1835. · 6.02 Impact Factor
-
Luca Olmi,
Peter A. R. Ade,
Daniel Angles-Alcazar,
James J. Bock,
Edward L. Chapin,
Massimo De Luca,
Mark J. Devlin,
Simon Dicker,
Davide Elia,
Giovanni G. Fazio, [......],
Douglas Scott,
Christopher Semisch,
Howard A. Smith,
Francesco Strafella,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
Donald V. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: The Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) carried out a 250, 350 and 500 micron survey of the galactic plane encompassing the Vela Molecular Ridge, with the primary goal of identifying the coldest dense cores possibly associated with the earliest stages of star formation. Here we present the results from observations of the Vela-D region, covering about 4 square degrees, in which we find 141 BLAST cores. We exploit existing data taken with the Spitzer MIPS, IRAC and SEST-SIMBA instruments to constrain their (single-temperature) spectral energy distributions, assuming a dust emissivity index beta = 2.0. This combination of data allows us to determine the temperature, luminosity and mass of each BLAST core, and also enables us to separate starless from proto-stellar sources. We also analyze the effects that the uncertainties on the derived physical parameters of the individual sources have on the overall physical properties of starless and proto-stellar cores, and we find that there appear to be a smooth transition from the pre- to the proto-stellar phase. In particular, for proto-stellar cores we find a correlation between the MIPS24 flux, associated with the central protostar, and the temperature of the dust envelope. We also find that the core mass function of the Vela-D cores has a slope consistent with other similar (sub)millimeter surveys. Comment: Accepted for publication in the Astrophysical Journal. Data and maps are available at http://blastexperiment.info/
10/2009;
-
Simon Dye,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
James S. Dunlop,
Stephen A. Eales,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern, [......], Marie Rex,
Douglas Scott,
Christopher Semisch,
Tom Targett,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
and Donald V. Wiebe
[show abstract]
[hide abstract]
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.
The Astrophysical Journal 08/2009; 703(1):285. · 6.02 Impact Factor
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Donald V. Wiebe,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon Dicker,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Enzo Pascale,
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero
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ABSTRACT: Over the course of two flights, the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) made resolved maps of seven nearby (<25 Mpc) galaxies at 250, 350, and 500 microns. During its June 2005 flight from Sweden, BLAST observed a single nearby galaxy, NGC 4565. During the December 2006 flight from Antarctica, BLAST observed the nearby galaxies NGC 1097, NGC 1291, NGC 1365, NGC 1512, NGC 1566, and NGC 1808. We fit physical dust models to a combination of BLAST observations and other available data for the galaxies observed by Spitzer. We fit a modified blackbody to the remaining galaxies to obtain total dust mass and mean dust temperature. For the four galaxies with Spitzer data, we also produce maps and radial profiles of dust column density and temperature. We measure the fraction of BLAST detected flux originating from the central cores of these galaxies and use this to calculate a "core fraction," an upper limit on the "AGN fraction" of these galaxies. We also find our resolved observations of these galaxies give a dust mass estimate 5-19 times larger than an unresolved observations would predict. Finally, we are able to use these data to derive a value for the dust mass absorption co-efficient of kappa = 0.29 +/-0.03 m^2 kg^-1 at 250 microns. This study is an introduction to future higher-resolution and higher-sensitivity studies to be conducted by Herschel and SCUBA-II. Comment: Submitted to ApJ. Data and related maps available at http://blastexperiment.info/
07/2009;
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Stephen Eales,
Edward L. Chapin,
Mark J. Devlin,
Simon Dye,
Mark Halpern,
David H. Hughes,
Gaelen Marsden,
Philip Mauskopf,
Lorenzo Moncelsi,
Calvin B. Netterfield,
Enzo Pascale,
Guillaume Patanchon,
Gwenifer Raymond, Marie Rex,
Douglas Scott,
Christopher Semisch,
Brian Siana,
Matthew D. P. Truch,
Marco P. Viero
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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. Comment: Accepted for publication in the Astrophysical Journal. Maps and associated results are available at http://blastexperiment.info/
The Astrophysical Journal 07/2009; · 6.02 Impact Factor
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Guillaume Patanchon,
Peter A. R. Ade,
James J. Bock,
Edward L. Chapin,
Mark J. Devlin,
Simon R. Dicker,
Matthew Griffin,
Joshua O. Gundersen,
Mark Halpern,
Peter C. Hargrave, [......],
Enzo Pascale, Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D. P. Truch,
Carole Tucker,
Gregory S. Tucker,
Marco P. Viero,
Donald V. Wiebe
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ABSTRACT: We describe the application of a statistical method to estimate submillimeter galaxy number counts from confusion limited observations by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Our method is based on a maximum likelihood fit to the pixel histogram, sometimes called 'P(D)', an approach which has been used before to probe faint counts, the difference being that here we advocate its use even for sources with relatively high signal-to-noise ratios. This method has an advantage over standard techniques of source extraction in providing an unbiased estimate of the counts from the bright end down to flux densities well below the confusion limit. We specifically analyse BLAST observations of a roughly 10 sq. deg. map centered on the Great Observatories Origins Deep Survey South (GOODS-S) field. We provide estimates of number counts at the three BLAST wavelengths, 250, 350, and 500 microns; instead of counting sources in flux bins we estimate the counts at several flux density nodes connected with power-laws. We observe a generally very steep slope for the counts of about -3.7 at 250 microns and -4.5 at 350 and 500 microns, over the range ~0.02-0.5 Jy, breaking to a shallower slope below about 0.015 Jy at all three wavelengths. We also describe how to estimate the uncertainties and correlations in this method so that the results can be used for model-fitting. This method should be well-suited for analysis of data from the Herschel satellite. Comment: Accepted for publication in the Astrophysical Journal; see associated data and other papers at http://blastexperiment.info/
06/2009;
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Mark J Devlin,
Peter A R Ade,
Itziar Aretxaga,
James J Bock,
Edward L Chapin,
Matthew Griffin,
Joshua O Gundersen,
Mark Halpern,
Peter C Hargrave,
David H Hughes, [......],
Guillaume Patanchon, Marie Rex,
Douglas Scott,
Christopher Semisch,
Nicholas Thomas,
Matthew D P Truch,
Carole Tucker,
Gregory S Tucker,
Marco P Viero,
Donald V Wiebe
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ABSTRACT: Submillimetre surveys during the past decade have discovered a population of luminous, high-redshift, dusty starburst galaxies. In the redshift range 1 <or= z <or= 4, these massive submillimetre galaxies go through a phase characterized by optically obscured star formation at rates several hundred times that in the local Universe. Half of the starlight from this highly energetic process is absorbed and thermally re-radiated by clouds of dust at temperatures near 30 K with spectral energy distributions peaking at 100 microm in the rest frame. At 1 <or= z <or= 4, the peak is redshifted to wavelengths between 200 and 500 microm. The cumulative effect of these galaxies is to yield extragalactic optical and far-infrared backgrounds with approximately equal energy densities. Since the initial detection of the far-infrared background (FIRB), higher-resolution experiments have sought to decompose this integrated radiation into the contributions from individual galaxies. Here we report the results of an extragalactic survey at 250, 350 and 500 microm. Combining our results at 500 microm with those at 24 microm, we determine that all of the FIRB comes from individual galaxies, with galaxies at z >or= 1.2 accounting for 70% of it. As expected, at the longest wavelengths the signal is dominated by ultraluminous galaxies at z > 1.
Nature 05/2009; 458(7239):737-9. · 36.28 Impact Factor
