The ALMA Spectroscopic Survey Large Program: The Infrared Excess of z=1.5-10 UV-selected Galaxies and the Implied High-Redshift Star Formation History
| Autor: | Bouwens, Rychard, Gonzalez-Lopez, Jorge, Aravena, Manuel, Decarli, Roberto, Novak, Mladen, Stefanon, Mauro, Walter, Fabian, Boogaard, Leindert, Carilli, Chris, Dudzeviciute, Ugne, Smail, Ian, Daddi, Emanuele, da Cunha, Elisabete, Ivison, Rob, Nanayakkara, Themiya, Cortes, Paulo, Cox, Pierre, Inami, Hanae, Oesch, Pascal, Popping, Gergo, Riechers, Dominik, van der Werf, Paul, Weiss, Axel, Fudamoto, Yoshi, Wagg, Jeff |
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| Rok vydání: | 2020 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/abb830 |
| Popis: | We make use of sensitive (9.3 microJy/beam RMS) 1.2mm-continuum observations from the ASPECS ALMA large program of the Hubble Ultra Deep Field (HUDF) to probe dust-enshrouded star formation from 1362 Lyman-break galaxies spanning the redshift range z=1.5-10 (to ~7-28 Msolar/yr at 4 sigma over the entire range). We find that the fraction of ALMA-detected galaxies in our z=1.5-10 samples increases steeply with stellar mass, with the detection fraction rising from 0% at 10^9 Msolar to 85(-18)(+9)% at >10^{10} Msolar. Moreover, stacking all 1253 low-mass (<10^{9.25} Msolar) galaxies over the ASPECS footprint, we find a mean continuum flux of -0.1+/-0.4 microJy/beam, implying a hard upper limit on the obscured SFR of <0.6 Msolar/yr (4 sigma) in a typical low-mass galaxy. The correlation between the infrared excess IRX of UV-selected galaxies (L(IR)/L(UV)) and the UV-continuum slope is also seen in our ASPECS data and shows consistency with a Calzetti-like relation at >10^{9.5} M_{solar} and a SMC-like relation at lower masses. Using stellar-mass and beta measurements for z~2 galaxies over CANDELS, we derive a new empirical relation between beta and stellar mass and then use this correlation to show that our IRX-beta and IRX-stellar mass relations are consistent with each other. We then use these constraints to express the infrared excess as a bivariate function of beta and stellar mass. Finally, we present updated estimates of star-formation rate density determinations at z>3, leveraging current improvements in the measured infrared excess and recent probes of ultra-luminous far-IR galaxies at z>2. Comment: 32 pages, 22 figures, 11 pages, accepted for publication in the Astrophysical Journal, key results shown in Figures 7, 8, 11, and 20, updated to match version in press |
| Databáze: | arXiv |
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