ALMA spectroscopic survey in the Hubble Ultra Deep Field: the infrared excess of UV-selected z = 2–10 galaxies as a function of UV-continuum slope and stellar mass

Journal Article · Sat Dec 10 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/833/1/72· OSTI ID:22868351

J Bouwens, Rychard; Labbé, Ivo; Hodge, Jacqueline ^[1]; Aravena, Manuel ^[2]; Decarli, Roberto; Walter, Fabian ^[3]; Da Cunha, Elisabete ^[4]; E Bauer, Franz ^[5]; Bertoldi, Frank; Karim, Alex; Magnelli, Benjamin ^[6]; Carilli, Chris ^[7]; Chapman, Scott ^[8]; Daddi, Emanuele ^[9]; J Ivison, Rob ^[10]; Le Fevre, Olivier ^[11]; Ota, Kazuaki ^[12]; others, and

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1. Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)
2. Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile)
3. Max-Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany)
4. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia)
5. Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile)
6. Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany)
7. NRAO, Pete V. Domenici Array Science Center, P.O. Box O, Socorro, NM 87801 (United States)
8. Dalhousie University, Halifax, Nova Scotia (Canada)
9. Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette cedex (France)
10. European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura Santiago (Chile)
11. IRAM, 300 rue de la piscine, F-38406 Saint-Martin d’Hères (France)
12. Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

We make use of deep 1.2 mm continuum observations (12.7 μJy beam{sup −1} rms) of a 1 arcmin{sup 2} region in the Hubble Ultra Deep Field to probe dust-enshrouded star formation from 330 Lyman-break galaxies spanning the redshift range z = 2–10 (to ∼2–3 M {sub ⊙} yr{sup −1} at 1σ over the entire range). Given the depth and area of ASPECS, we would expect to tentatively detect 35 galaxies, extrapolating the Meurer z ∼ 0 IRX–β relation to z ≥ 2 (assuming dust temperature T {sub d} ∼ 35 K). However, only six tentative detections are found at z ≳ 2 in ASPECS, with just three at >3σ. Subdividing our z = 2–10 galaxy samples according to stellar mass, UV luminosity, and UV-continuum slope and stacking the results, we find a significant detection only in the most massive (>10{sup 9.75} M {sub ⊙}) subsample, with an infrared excess (IRX = L {sub IR}/L {sub UV}) consistent with previous z ∼ 2 results. However, the infrared excess we measure from our large selection of sub-L {sup ∗} (<10{sup 9.75} M {sub ⊙}) galaxies is 0.11{sub −0.42}{sup +0.32} ± 0.34 (bootstrap and formal uncertainties) and 0.14{sub −0.14}{sup +0.15} ± 0.18 at z = 2–3 and z = 4–10, respectively, lying below even an IRX–β relation for the Small Magellanic Cloud (95% confidence). These results demonstrate the relevance of stellar mass for predicting the IR luminosity of z ≳ 2 galaxies. We find that the evolution of the IRX–stellar mass relationship depends on the evolution of the dust temperature. If the dust temperature increases monotonically with redshift (∝(1+z){sup 0.32}) such that T {sub d} ∼ 44–50 K at z ≥ 4, current results are suggestive of little evolution in this relationship to z ∼ 6. We use these results to revisit recent estimates of the z ≥ 3 star formation rate density.

• OSTI ID: 22868351
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 833; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC DUST
DENSITY
DETECTION
GALACTIC EVOLUTION
INTERFEROMETERS
LUMINOSITY
MAGELLANIC CLOUDS
MASS
RED SHIFT
STARS
STATISTICS