TY - JOUR
T1 - A Tale of Two Clusters
T2 - An Analysis of Gas-phase Metallicity and Nebular Gas Conditions in Proto-cluster Galaxies at z ∼ 2
AU - Alcorn, Leo Y.
AU - Gupta, Anshu
AU - Tran, Kim Vy
AU - Kacprzak, Glenn G.
AU - Yuan, Tiantian
AU - Cohn, Jonathan
AU - Forrest, Ben
AU - Glazebrook, Karl
AU - Harshan, Anishya
AU - Kewley, Lisa J.
AU - Labbé, Ivo
AU - Nanayakkara, Themiya
AU - Papovich, Casey
AU - Spitler, Lee R.
AU - Straatman, Caroline M.S.
N1 - Publisher Copyright:
© 2019 The American Astronomical Society. All rights reserved.
PY - 2019
Y1 - 2019
N2 - The ZFIRE survey has spectroscopically confirmed two proto-clusters using the MOSFIRE instrument on Keck I: One at z = 2.095 in COSMOS and another at z = 1.62 in UKIRT Infrared Deep Sky Survey (UDS). Here, we use an updated ZFIRE data set to derive the properties of ionized gas regions of proto-cluster galaxies by extracting fluxes from emission lines Hβ 4861 Å, [O iii] 5007 Å, Hα 6563 Å, [N ii] 6585 Å, and [S ii] 6716,6731 Å. We measure gas-phase metallicity of members in both proto-clusters using two indicators, including a strong-line indicator relatively independent of the ionization parameter and electron density. Proto-cluster and field galaxies in both UDS and COSMOS lie on the same Mass-Metallicity Relation with both metallicity indicators. We compare our results to recent IllustrisTNG results, which report no significant gas-phase metallicity offset between proto-cluster and field galaxies until z = 1.5. This is in agreement with our observed metallicities, where no offset is measured between proto-cluster and field populations. We measure tentative evidence from stacked spectra that indicate UDS high-mass proto-cluster and field galaxies have differing [O iii]/Hβ ratios; however, these results are dependent on the sample size of the high-mass stacks.
AB - The ZFIRE survey has spectroscopically confirmed two proto-clusters using the MOSFIRE instrument on Keck I: One at z = 2.095 in COSMOS and another at z = 1.62 in UKIRT Infrared Deep Sky Survey (UDS). Here, we use an updated ZFIRE data set to derive the properties of ionized gas regions of proto-cluster galaxies by extracting fluxes from emission lines Hβ 4861 Å, [O iii] 5007 Å, Hα 6563 Å, [N ii] 6585 Å, and [S ii] 6716,6731 Å. We measure gas-phase metallicity of members in both proto-clusters using two indicators, including a strong-line indicator relatively independent of the ionization parameter and electron density. Proto-cluster and field galaxies in both UDS and COSMOS lie on the same Mass-Metallicity Relation with both metallicity indicators. We compare our results to recent IllustrisTNG results, which report no significant gas-phase metallicity offset between proto-cluster and field galaxies until z = 1.5. This is in agreement with our observed metallicities, where no offset is measured between proto-cluster and field populations. We measure tentative evidence from stacked spectra that indicate UDS high-mass proto-cluster and field galaxies have differing [O iii]/Hβ ratios; however, these results are dependent on the sample size of the high-mass stacks.
KW - galaxies: Clusters: General
KW - galaxies: Evolution
KW - galaxies: High-redshift
UR - http://www.scopus.com/inward/record.url?scp=85073694989&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/ab3b0c
DO - 10.3847/1538-4357/ab3b0c
M3 - Article
SN - 0004-637X
VL - 883
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 153
ER -