Evolution of cosmic star formation in the SCUBA-2 Cosmology Legacy Survey
Date Issued
2017
Author(s)
Bourne, N.
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Dunlop, J. S.
•
•
Parsa, S.
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Schreiber, C.
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Conselice, C. J.
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Coppin, K. E. K.
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Farrah, D.
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Geach, J. E.
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Halpern, M.
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Knudsen, K. K.
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Michałowski, M. J.
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Mortlock, A.
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•
Scott, D.
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Shu, X. W.
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Simpson, C.
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Simpson, J. M.
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Smith, D. J. B.
•
van der Werf, P. P.
Abstract
We present a new exploration of the cosmic star formation history and dust obscuration in massive galaxies at redshifts 0.5 < z < 6. We utilize the deepest 450- and 850-μm imaging from SCUBA-2 CLS, covering 230 arcmin2 in the AEGIS, COSMOS and UDS fields, together with 100-250 μm imaging from Herschel. We demonstrate the capability of the t-phot deconfusion code to reach below the confusion limit, using multiwavelength prior catalogues from CANDELS/3D-HST. By combining IR and UV data, we measure the relationship between total star formation rate (SFR) and stellar mass up to z ∼ 5, indicating that UV-derived dust corrections underestimate the SFR in massive galaxies. We investigate the relationship between obscuration and the UV slope (the IRX-β relation) in our sample, which is similar to that of low-redshift starburst galaxies, although it deviates at high stellar masses. Our data provide new measurements of the total SFR density (SFRD) in M_{\ast }>10^{10} M_{☉} galaxies at 0.5 < z < 6. This is dominated by obscured star formation by a factor of >10. One third of this is accounted for by 450-μm-detected sources, while one-fifth is attributed to UV-luminous sources (brighter than L_UV^\ast), although even these are largely obscured. By extrapolating our results to include all stellar masses, we estimate a total SFRD that is in good agreement with previous results from IR and UV data at z ≲ 3, and from UV-only data at z ∼ 5. The cosmic star formation history undergoes a transition at z ∼ 3-4, as predominantly unobscured growth in the early Universe is overtaken by obscured star formation, driven by the build-up of the most massive galaxies during the peak of cosmic assembly.
Volume
467
Issue
2
Start page
1360
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.467.1360B
Rights
open.access
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