The Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) carried out a 250, 350, and 500 Delta *mm 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 deg2, 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 Delta *b = 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 protostellar 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 protostellar cores, and we find that there appear to be a smooth transition from the pre- to the protostellar phase. In particular, for protostellar 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.
We present a study of the cosmic infrared background, which is a measure of the dust-obscured activity in all galaxies in the Universe. We venture to isolate the galaxies responsible for the ...background at 1mm; with spectroscopic and photometric redshifts we constrain the redshift distribution of these galaxies. We create a deep 1.16mm map (σ 0.5mJy) by combining the AzTEC 1.1mm and MAMBO 1.2mm data sets in the Great Observatories Origins Deep Survey North (GOODS-N) region. This combined map contains 41 secure detections, 13 of which are new. By averaging the 1.16mm flux densities of individually undetected galaxies with 24μm flux densities >25μJy, we resolve 31-45 per cent of the 1.16mm background. Repeating our analysis on the SCUBA 850μm map, we resolve a higher percentage (40-64 per cent) of the 850μm background. A majority of the background resolved (attributed to individual galaxies) at both wavelengths comes from galaxies at z > 1.3. If the ratio of the resolved submillimetre to millimetre background is applied to a reasonable scenario for the origins of the unresolved submillimetre background, 60-88 per cent of the total 1.16mm background comes from galaxies at z > 1.3. PUBLICATION ABSTRACT
We have imaged an 11.5 deg{sup 2} region of sky toward the South Ecliptic Pole (R.A. =04{sup h}43{sup m}, decl. =-53{sup 0}40', J2000) at 24 and 70 {mu}m with MIPS, the Multiband Imaging Photometer ...for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and BLAST. We discuss our data reduction and source extraction procedures. The median 1{sigma} depths of the maps are 47 {mu}Jy beam{sup -1} at 24 {mu}m and 4.3 mJy beam{sup -1} at 70 {mu}m. At 24 {mu}m, we identify 93,098 point sources with signal-to-noise ratio (S/N) {>=}5 and an additional 63 resolved galaxies; at 70 {mu}m we identify 891 point sources with S/N {>=}6. From simulations, we determine a false detection rate of 1.8% (1.1%) for the 24 {mu}m (70 {mu}m) catalog. The 24 and 70 {mu}m point-source catalogs are 80% complete at 230 {mu}Jy and 11 mJy, respectively. These mosaic images and source catalogs will be available to the public through the NASA/IPAC Infrared Science Archive.
\We present a joint analysis of the overlapping Balloon-borne Large Aperture Submillimetre Telescope (BLAST) 250, 350, 500μm, and LABOCA 870μm observations from the LABOCA ECDFS Submm Survey (LESS) ...survey of the Extended Chandra Deep Field-South. Out to z 3, the BLAST filters sample near the peak wavelength of thermal far-infrared (FIR) emission from galaxies (rest-frame wavelengths 60-200μm), primarily produced by dust heated through absorption in star-forming clouds. However, identifying counterparts to individual BLAST peaks is very challenging, given the large beams full-width at half-maximum (FWHM) 36-60arcsec. In contrast, the ground-based 870μm observations have a significantly smaller 19arcsec FWHM beam, and are sensitive to higher redshifts (z 1-5, and potentially beyond) due to the more favourable negative K-correction. We use the LESS data, as well as deep Spitzer and VLA imaging, to identify 118 individual sources that produce significant emission in the BLAST bands. We characterize the temperatures and FIR luminosities for a subset of 69 sources which have well-measured submillimetre (submm) spectral energy distributions (SEDs) and redshift measurements out to z 3. For flux-limited sub-samples in each BLAST band, and a dust emissivity index β= 2.0, we find a median temperature T= 30K (all bands) as well as median redshifts: z= 1.1 (interquartile range 0.2-1.9) for S250 > 40mJy; z= 1.3 (interquartile range 0.6-2.1) for S350 > 30mJy; and z= 1.6 (interquartile range 1.3-2.3) for S500 > 20mJy. Taking into account the selection effects for our survey (a bias towards detecting lower-temperature galaxies), we find no evidence for evolution in the local FIR-temperature correlation out to z 2.5. Comparing with star-forming galaxy SED templates, about 8 per cent of our sample appears to exhibit significant excesses in the radio and/or mid-IR, consistent with those sources harbouring active galactic nuclei (AGN). Since our statistical approach differs from most previous studies of submm galaxies, we describe the following techniques in two appendices: our 'matched filter' for identifying sources in the presence of point-source confusion; and our approach for identifying counterparts using likelihood ratios. This study is a direct precursor to future joint FIR/submm surveys, for which we outline a potential identification and SED measurement strategy. PUBLICATION ABSTRACT
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