The VLA-COSMOS 3 GHz Large Project: Cosmic star formation history since z 5
Journal
Date Issued
2017
Author(s)
Novak, M.
•
Smolčić, V.
•
Delhaize, J.
•
•
Zamorani, G.
•
Baran, N.
•
•
Capak, P.
•
Carilli, C. L.
•
•
Civano, F.
•
Ilbert, O.
•
Karim, A.
•
Laigle, C.
•
Le Fèvre, O.
•
•
McCracken, H.
•
Miettinen, O.
•
Salvato, M.
•
Sargent, M.
•
Schinnerer, E.
•
Tasca, L.
Abstract
We make use of the deep Karl G. Jansky Very Large Array (VLA) COSMOS radio observations at 3 GHz to infer radio luminosity functions of star-forming galaxies up to redshifts of z 5 based on approximately 6000 detections with reliable optical counterparts. This is currently the largest radio-selected sample available out to z 5 across an area of 2 square degrees with a sensitivity of rms ≈ 2.3 μJy beam-1. By fixing the faint and bright end shape of the radio luminosity function to the local values, we find a strong redshift trend that can be fitted with a pure luminosity evolution L1.4 GHz ∝ (1 + z)(3.16 ± 0.2)-(0.32 ± 0.07)z. We estimate star formation rates (SFRs) from our radio luminosities using an infrared (IR)-radio correlation that is redshift dependent. By integrating the parametric fits of the evolved luminosity function we calculate the cosmic SFR density (SFRD) history since z 5. Our data suggest that the SFRD history peaks between 2 < z < 3 and that the ultraluminous infrared galaxies (100 M☉ yr-1 < SFR < 1000 M☉ yr-1) contribute up to 25% to the total SFRD in the same redshift range. Hyperluminous infrared galaxies (SFR > 1000 M☉ yr-1) contribute an additional ≲2% in the entire observed redshift range. We find evidence of a potential underestimation of SFRD based on ultraviolet (UV) rest-frame observations of Lyman break galaxies at high redshifts (z ≳ 4) on the order of 15-20%, owing to appreciable star formation in highly dust-obscured galaxies, which might remain undetected in such UV observations.
Volume
602
Start page
A5
Issn Identifier
0004-6361
Ads BibCode
2017A&A...602A...5N
Rights
open.access
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