The VLA-COSMOS 3 GHz Large Project: Cosmic star formation history since z 5

Scientific paper - Original scientific paper

• Author: Mladen Novak; MBZ: 344074
• Author: Vernesa Smolčić; MBZ: 336180
• Author: J. Delhaize
• Author: I. Delvecchio
• Author: G. Zamorani
• Author: N. Baran
• Author: M. Bondi
• Author: P. Capak
• Author: C. L. Carilli
• Author: P. Ciliegi
• Author: F. Civano
• Author: O. Ilbert
• Author: A. Karim
• Author: C. Laigle
• Author: O. Le Fèvre
• Author: S. Marchesi
• Author: H. McCracken
• Author: O. Miettinen
• Author: M. Salvato
• Author: M. Sargent
• Author: E. Schinnerer
• Author: L. Tasca
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics; Astronomy and Astrophysics

Abstract (english)

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 L_(1.4 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.

• Keywords (english): galaxies; evolution – galaxies; star formation – cosmology; observations – radio continuum; galaxies
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Astronomy and Astrophysics
• Numbering: vol. 602, A5
• p-ISSN: 0004-6361
• e-ISSN: 1432-0746
• DOI: https://doi.org/10.1051/0004-6361/201629436
• URN:NBN: urn:nbn:hr:217:788057
• Publication: 2017
• Document URL: https://www.aanda.org/articles/aa/abs/2017/06/aa29436-16/aa29436-16.html
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2017 ESO. Article published by EDP Sciences. Received 29 July 2016; Accepted 15 January 2017; Published online 13 June 2017. This research was funded by the European Unions Seventh Frame-work program under grant agreement 337595 (ERC Starting Grant, “CoSMass”). E.S. warmly acknowledges support from the National Radio Astronomy Observatory for visits to the Array Operations Center in Socorro, NM, in conjunction with this project. A.K. acknowledges support by the Collaborative Research Council 956, sub-project A1, funded by the Deutsche Forschungsgemeinschaft (DFG). M.B. and P.C. acknowledge support from the PRIN-INAF 2014.
• Created on: 2020-02-27 21:10:54