The VLA-COSMOS 3 GHz Large Project: Evolution of Specific Star Formation Rates out to z ∼ 5

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  • Sarah K. Leslie
  • Eva Schinnerer
  • Daizhong Liu
  • Benjamin Magnelli
  • Hiddo Algera
  • Alexander Karim
  • Iary Davidzon
  • Ghassem Gozaliasl
  • Eric F. Jiménez-Andrade
  • Philipp Lang
  • Mark T. Sargent
  • Mladen Novak
  • Brent Groves
  • Vernesa Smolčić
  • Giovanni Zamorani
  • Mattia Vaccari
  • Andrew Battisti
  • Eleni Vardoulaki
  • Yingjie Peng
  • Jeyhan Kartaltepe
We provide a coherent, uniform measurement of the evolution of the logarithmic star formation rate (SFR)-stellar mass (M*) relation, called the main sequence (MS) of star-forming galaxies , for star-forming and all galaxies out to $z\sim 5$ . We measure the MS using mean stacks of 3 GHz radio-continuum images to derive average SFRs for ∼ 200,000 mass-selected galaxies at z > 0.3 in the COSMOS field. We describe the MS relation by adopting a new model that incorporates a linear relation at low stellar mass (log(M*/M⊙) <10) and a flattening at high stellar mass that becomes more prominent at low redshift (z <1.5). We find that the SFR density peaks at 1.5 <z <2, and at each epoch there is a characteristic stellar mass (M* = 1-4 × 1010M⊙) that contributes the most to the overall SFR density. This characteristic mass increases with redshift, at least to z ∼ 2.5. We find no significant evidence for variations in the MS relation for galaxies in different environments traced by the galaxy number density at 0.3 <z <3, nor for galaxies in X-ray groups at z ∼ 0.75. We confirm that massive bulge-dominated galaxies have lower SFRs than disk-dominated galaxies at a fixed stellar mass at z <1.2. As a consequence, the increase in bulge-dominated galaxies in the local star-forming population leads to a flattening of the MS at high stellar masses. This indicates that "mass quenching" is linked with changes in the morphological composition of galaxies at a fixed stellar mass.
OriginalsprogEngelsk
Artikelnummer58
TidsskriftAstrophysical Journal
Vol/bind899
Udgave nummer1
Antal sider37
ISSN0004-637X
DOI
StatusUdgivet - 1 aug. 2020

ID: 248148640