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

Autori
Novak, Mladen ; Smolčić, Vernesa ; Delhaize, J. ; Delvecchio, I. ; Zamorani, G. ; Baran, N. ; Bondi, M. ; Capak, P. ; Carilli, C. L. ; Ciliegi, P. ; Civano, F. ; Ilbert, O. ; Karim, A. ; Laigle, C. ; Le Fèvre, O. ; Marchesi, S. ; McCracken, H. ; Miettinen, O. ; Salvato, M. ; Sargent, M. ; Schinnerer, E. ; Tasca, L.

Izvornik
Astronomy & astrophysics (Berlin) (0004-6361) 602 (2017); A5, 17

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
galaxies, evolution – galaxies, star formation – cosmology, observations – radio continuum, galaxies

Sažetak
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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA