TY - JOUR
T1 - The MOSDEF Survey
T2 - The Metallicity Dependence of X-Ray Binary Populations at z ∼ 2
AU - Fornasini, Francesca M.
AU - Kriek, Mariska
AU - Sanders, Ryan L.
AU - Shivaei, Irene
AU - Civano, Francesca
AU - Reddy, Naveen A.
AU - Shapley, Alice E.
AU - Coil, Alison L.
AU - Mobasher, Bahram
AU - Siana, Brian
AU - Aird, James
AU - Azadi, Mojegan
AU - Freeman, William R.
AU - Leung, Gene C.K.
AU - Price, Sedona H.
AU - Fetherolf, Tara
AU - Zick, Tom
AU - Barro, Guillermo
N1 - Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Population synthesis models predict that high-mass X-ray binary (HMXB) populations produced in low-metallicity environments should be more X-ray luminous, a trend supported by studies of nearby galaxies. This trend may be responsible for the observed increase of the X-ray luminosity (L X) per star formation rate (SFR) with redshift due to the decrease of metallicity (Z) at fixed stellar mass as a function of redshift. To test this hypothesis, we use a sample of 79 z ∼ 2 star-forming galaxies with oxygen abundance measurements from the MOSDEF survey, which obtained rest-frame optical spectra for ∼1500 galaxies in the CANDELS fields at 1.37 < z < 3.80. Using Chandra data from the Chandra AEGIS-X Deep, Chandra Deep Field North, and Chandra Deep Field South surveys, we stack the X-ray data at the galaxy locations in bins of redshift and Z because the galaxies are too faint to be individually detected. In agreement with previous studies, the average L X/SFR of our z ∼ 2 galaxy sample is enhanced by ≈0.4-0.8 dex relative to local HMXB L X-SFR scaling relations. Splitting our sample by Z, we find that L X/SFR and Z are anticorrelated with 97% confidence. This observed Z dependence for HMXB-dominated galaxies is consistent with both the local L X-SFR-Z relation and a subset of population synthesis models. Although the statistical significance of the observed trends is weak owing to the low X-ray statistics, these results constitute the first direct evidence connecting the redshift evolution of L X/SFR and the Z dependence of HMXBs.
AB - Population synthesis models predict that high-mass X-ray binary (HMXB) populations produced in low-metallicity environments should be more X-ray luminous, a trend supported by studies of nearby galaxies. This trend may be responsible for the observed increase of the X-ray luminosity (L X) per star formation rate (SFR) with redshift due to the decrease of metallicity (Z) at fixed stellar mass as a function of redshift. To test this hypothesis, we use a sample of 79 z ∼ 2 star-forming galaxies with oxygen abundance measurements from the MOSDEF survey, which obtained rest-frame optical spectra for ∼1500 galaxies in the CANDELS fields at 1.37 < z < 3.80. Using Chandra data from the Chandra AEGIS-X Deep, Chandra Deep Field North, and Chandra Deep Field South surveys, we stack the X-ray data at the galaxy locations in bins of redshift and Z because the galaxies are too faint to be individually detected. In agreement with previous studies, the average L X/SFR of our z ∼ 2 galaxy sample is enhanced by ≈0.4-0.8 dex relative to local HMXB L X-SFR scaling relations. Splitting our sample by Z, we find that L X/SFR and Z are anticorrelated with 97% confidence. This observed Z dependence for HMXB-dominated galaxies is consistent with both the local L X-SFR-Z relation and a subset of population synthesis models. Although the statistical significance of the observed trends is weak owing to the low X-ray statistics, these results constitute the first direct evidence connecting the redshift evolution of L X/SFR and the Z dependence of HMXBs.
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U2 - 10.3847/1538-4357/ab4653
DO - 10.3847/1538-4357/ab4653
M3 - Article
AN - SCOPUS:85075241182
SN - 0004-637X
VL - 885
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 65
ER -