We compare galaxy scaling relations as a function of environment at z∼2
with our ZFIRE survey where we have measured Hα fluxes for 90
star-forming galaxies selected from a mass-limited
[log(M⋆/M⊙)>9] sample based on ZFOURGE. The cluster galaxies
(37) are part of a confirmed system at z=2.095 and the field galaxies (53) are
at 1.9<z<2.4; all are in the COSMOS legacy field. There is no statistical
difference between Hα-emitting cluster and field populations when
comparing their star formation rate (SFR), stellar mass (M⋆), galaxy
size (reff), SFR surface density [Σ(Hαstar)], and stellar
age distributions. The only difference is that at fixed stellar mass, the
Hα-emitting cluster galaxies are log(reff)∼0.1 larger than in
the field. Approximately 19% of the Hα-emitters in the cluster and 26%
in the field are IR-luminous (LIR>2×1011L⊙). Because the
LIRGs in our combined sample are ∼5 times more massive than the low-IR
galaxies, their radii are ∼70% larger. To track stellar growth, we
separate galaxies into those that lie above, on, and below the Hα
star-forming main sequence (SFMS) using ΔSFR(M⋆)=±0.2 dex.
Galaxies above the SFMS (starbursts) tend to have higher Hα SFR surface
densities and younger light-weighted stellar ages compared to galaxies below
the SFMS. Our results indicate that starbursts (+SFMS) in the cluster and field
at z∼2 are growing their stellar cores. Lastly, we compare to the
(SFR-M⋆) relation from RHAPSODY cluster simulations and find the
predicted slope is nominally consistent with the observations. However, the
predicted cluster SFRs tend to be too low by a factor of ∼2 which seems to
be a common problem for simulations across environment.Comment: ApJ in press; full version of Table 1 available from ApJ and upon
request. Survey websites are http://zfire.swinburne.edu.au and
http://zfourge.tamu.ed