TY - JOUR
T1 - Zfire
T2 - Similar stellar growth in hα-emitting cluster and field galaxies at z ∼ 2
AU - Tran, Kim Vy H.
AU - Alcorn, Leo Y.
AU - Kacprzak, Glenn G.
AU - Nanayakkara, Themiya
AU - Straatman, Caroline
AU - Yuan, Tiantian
AU - Cowley, Michael
AU - Davé, Romeel
AU - Glazebrook, Karl
AU - Kewley, Lisa J.
AU - Labbé, Ivo
AU - Martizzi, Davidé
AU - Papovich, Casey
AU - Quadri, Ryan
AU - Spitler, Lee R.
AU - Tomczak, Adam
N1 - Funding Information:
This work was supported by a NASA Keck PI Data Award administered by the NASA Exoplanet Science Institute. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to NASA through the agency's scientific partnership with the California Institute of Technology and the University of California.
PY - 2017/1/10
Y1 - 2017/1/10
N2 - We compare galaxy scaling relations as a function of environment at z ∼ 2 with our ZFIRE survey12 where we have measured Hα fluxes for 90 star-forming galaxies selected from a mass-limited (log(Mz.astModot) > 9) sample based on ZFOURGE.13 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(H star)), 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>× 1011 L⊙). Because the luminous IR galaxies 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, or 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 than 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-G cluster simulations and find that 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.
AB - We compare galaxy scaling relations as a function of environment at z ∼ 2 with our ZFIRE survey12 where we have measured Hα fluxes for 90 star-forming galaxies selected from a mass-limited (log(Mz.astModot) > 9) sample based on ZFOURGE.13 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(H star)), 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>× 1011 L⊙). Because the luminous IR galaxies 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, or 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 than 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-G cluster simulations and find that 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.
KW - galaxies: evolution
KW - galaxies: star formation
KW - galaxies: starburst
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U2 - 10.3847/1538-4357/834/2/101
DO - 10.3847/1538-4357/834/2/101
M3 - Article
AN - SCOPUS:85010041702
SN - 0004-637X
VL - 834
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 101
ER -