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

Bouwens, R.J.; Aravena, M.; Decarli, R.; Walter, F.; da Cunha, E.; Labbé, I.; Bauer, F.E.; Bertoldi, F.; Carilli, C.; Chapman, S.; Daddi, E.; Hodge, J.; Ivison, R.J.; Karim, A.; Le Fevre, O.; Magnelli, B.; Ota, K.; Riechers, D.; Smail, I.R.; van der Werf, P.; Weiss, A.; Cox, P.; Elbaz, D.; Gonzalez-Lopez, J.; Infante, L.; Oesch, P.; Wagg, J.; Wilkins, S.

doi:10.3847/1538-4357/833/1/72

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

Bouwens, R.J.; Aravena, M.; Decarli, R.; Walter, F.; da Cunha, E.; Labbé, I.; Bauer, F.E.; Bertoldi, F.; Carilli, C.; Chapman, S.; Daddi, E.; Hodge, J.; Ivison, R.J.; Karim, A.; Le Fevre, O.; Magnelli, B.; Ota, K.; Riechers, D.; Smail, I.R.; van der Werf, P.; Weiss, A.; Cox, P.; Elbaz, D.; Gonzalez-Lopez, J.; Infante, L.; Oesch, P.; Wagg, J.; Wilkins, S.

Authors

R.J. Bouwens

M. Aravena

R. Decarli

F. Walter

E. da Cunha

I. Labbé

F.E. Bauer

F. Bertoldi

C. Carilli

S. Chapman

E. Daddi

J. Hodge

R.J. Ivison

A. Karim

O. Le Fevre

B. Magnelli

K. Ota

D. Riechers

Professor Ian Smail ian.smail@durham.ac.uk
Emeritus Professor

P. van der Werf

A. Weiss

P. Cox

D. Elbaz

J. Gonzalez-Lopez

L. Infante

P. Oesch

J. Wagg

S. Wilkins

Abstract

We make use of deep 1.2 mm continuum observations (12.7 μJy beam-1 rms) of a 1 arcmin2 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 ⊙ yr-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 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 (>109.75 M ⊙) subsample, with an infrared excess (IRX = L IR/L UV) consistent with previous z ˜ 2 results. However, the infrared excess we measure from our large selection of sub-L ∗ (<109.75 M ⊙) galaxies is {0.11}-0.42+0.32 ± 0.34 (bootstrap and formal uncertainties) and {0.14}-0.14+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 (\propto {(1+z)}0.32) such that T 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.

Citation

Bouwens, R., Aravena, M., Decarli, R., Walter, F., da Cunha, E., Labbé, I., …Wilkins, S. (2016). 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. Astrophysical Journal, 833(1), Article 72. https://doi.org/10.3847/1538-4357/833/1/72

Journal Article Type	Article
Acceptance Date	Aug 3, 2016
Online Publication Date	Dec 8, 2016
Publication Date	Dec 8, 2016
Deposit Date	Feb 22, 2017
Publicly Available Date	Mar 9, 2017
Journal	Astrophysical Journal
Print ISSN	0004-637X
Electronic ISSN	1538-4357
Publisher	American Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	833
Issue	1
Article Number	72
DOI	https://doi.org/10.3847/1538-4357/833/1/72
Related Public URLs	http://sro.sussex.ac.uk/id/eprint/66951/