The VLA-COSMOS 3 GHz Large Project: Evolution of Specific Star Formation Rates out to z ∼ 5
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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.
Originalsprog | Engelsk |
---|---|
Artikelnummer | 58 |
Tidsskrift | Astrophysical Journal |
Vol/bind | 899 |
Udgave nummer | 1 |
Antal sider | 37 |
ISSN | 0004-637X |
DOI | |
Status | Udgivet - 1 aug. 2020 |
Links
- http://adsabs.harvard.edu/abs/2020ApJ...899...58L
Forlagets udgivne version
ID: 248148640