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Title: A LABOCA SURVEY OF THE EXTENDED CHANDRA DEEP FIELD SOUTH-SUBMILLIMETER PROPERTIES OF NEAR-INFRARED SELECTED GALAXIES

Journal Article · · Astrophysical Journal
; ; ; ; ;  [1]; ;  [2]; ; ;  [3];  [4]; ;  [5];  [6];  [7];  [8];  [9];  [10]
  1. Max-Planck-Institut fuer Astronomie, 69117 Heidelberg (Germany)
  2. Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany)
  3. Institute for Computational Cosmology, Durham University, Durham DH1 6BH (United Kingdom)
  4. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
  5. Argelander Institute for Astronomy, University of Bonn, 53121 Bonn (Germany)
  6. European Southern Observatory, Garching (Germany)
  7. National Optical Astronomical Observatory, Tucson, AZ 85719 (United States)
  8. Department of Astronomy, Yale University, New Haven, CT (United States)
  9. Max-Planck-Institut fuer extraterrestrische Physik, 85741 Garching (Germany)
  10. Pennsylvania State University, Astronomy and Astrophysics 525 Davey Lab, University Park, PA 16802 (United States)

Using the 330 hr ESO-MPG 870 {mu}m survey of the Extended Chandra Deep Field South (ECDF-S) obtained with the Large Apex BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX), we have carried out a stacking analysis at submillimeter (submm) wavelengths of a sample of 8266 near-infra-red (near-IR) selected (K {sub vega} {<=} 20) galaxies, including 893 BzK galaxies, 1253 extremely red objects (EROs), and 737 distant red galaxies (DRGs), selected from the Multi-wavelength Survey by Yale-Chile (MUSYC). We measure average 870 {mu}m fluxes of 0.22 {+-} 0.01 mJy (22.0{sigma}), 0.48 {+-} 0.04 mJy (12.0{sigma}), 0.39 {+-} 0.03 mJy (13.0{sigma}), and 0.43 {+-} 0.04 mJy (10.8{sigma}) for the K {sub vega} {<=} 20, BzK, ERO, and DRG samples, respectively. For the BzK, ERO, and DRG sub-samples, which overlap to some degree and are likely to be at z {approx_equal} 1-2, this implies an average far-IR luminosity of {approx}(1-5) x 10{sup 11} L{sub sun} and star formation rate (SFR) of {approx}20-90 M{sub sun} . Splitting the BzK galaxies into star-forming (sBzK) and passive (pBzK) galaxies, the former is significantly detected (0.50 {+-} 0.04 mJy, 12.5{sigma}) while the latter is only marginally detected (0.34 {+-} 0.10 mJy, 3.4{sigma}), thus confirming that the sBzK and pBzK criteria to some extent select obscured, star-forming, and truly passive galaxies, respectively. The K {sub vega} {<=} 20 galaxies are found to contribute 7.27 {+-} 0.34 Jy deg{sup -2} (16.5% {+-} 5.7%) to the 870 {mu}m extragalactic background light (EBL). sBzK and pBzK galaxies contribute 1.49 {+-} 0.22 Jy deg{sup -2} (3.4% {+-} 1.3%) and 0.20 {+-} 0.14 Jy deg{sup -2} (0.5% {+-} 0.3%) to the EBL. We present the first delineation of the average submm signal from the K {sub vega} {<=} 20 selected galaxies and their contribution to the submm EBL as a function of (photometric) redshift, and find a decline in the average submm signal (and therefore IR luminosity and SFR) by a factor {approx}2-3 from z {approx} 2 to z {approx} 0. This is in line with a cosmic star formation history in which the star formation activity in galaxies increases significantly at z {approx}> 1. A linear correlation between the average 24 {mu}m and 870 {mu}m flux densities is found for the K {sub vega} {<=} 20 galaxies with 24 {mu}m fluxes {approx}<350 {mu}Jy (corresponding to L {sub IR} {approx_equal} 1.5 x 10{sup 12} L{sub sun} at z {approx_equal} 2), while at higher 24 {mu}m fluxes there is no correlation. This behavior suggests that star formation, and not active galactic nuclei (AGNs), is in general responsible for the bulk of the mid-IR emission of L {sub IR} {approx}< 1.5 x 10{sup 12} L{sub sun} systems, while in more luminous systems the AGN makes a significant contribution to the 24 {mu}m emission. By mapping the stacked 870 {mu}m signal across the B - z versus z - K diagram we have confirmed the ability of the sBzK selection criterion to select star-forming galaxies at z > 1, although our analysis suggests that the subset of sBzK galaxies which are also EROs are responsible for >80% of the submm emission from the entire sBzK population.

OSTI ID:
21454994
Journal Information:
Astrophysical Journal, Vol. 719, Issue 1; Other Information: DOI: 10.1088/0004-637X/719/1/483; ISSN 0004-637X
Country of Publication:
United States
Language:
English