1. The VANDELS Survey:new constraints on the high-mass X-ray binary populations in normal star-forming galaxies at 3 < z < 5.5
- Author
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A Saxena, R S Ellis, P U Förster, A Calabrò, L Pentericci, A C Carnall, M Castellano, F Cullen, A Fontana, M Franco, J P U Fynbo, A Gargiulo, B Garilli, N P Hathi, D J McLeod, R Amorín, and G Zamorani
- Subjects
EMITTING GALAXIES ,Astrophysics::High Energy Astrophysical Phenomena ,X-ray binary ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Star (graph theory) ,SCALING RELATIONS ,01 natural sciences ,LY-ALPHA ,ULTRAVIOLET-SPECTRA ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,License ,Astrophysics::Galaxy Astrophysics ,evolution [galaxies] ,Physics ,010308 nuclear & particles physics ,CANDELS ,REIONIZATION ,Astronomy ,Astronomy and Astrophysics ,Creative commons ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Space and Planetary Science ,EMISSION-LINE SPECTRA ,Astrophysics of Galaxies (astro-ph.GA) ,High mass ,LUMINOSITY ,binaries [X-rays] ,STELLAR-MASS ,METALLICITY ,high-redshift [galaxies] - Abstract
We use VANDELS spectroscopic data overlapping with the $\simeq$7 Ms Chandra Deep Field South survey to extend studies of high-mass X-ray binary systems (XRBs) in 301 normal star-forming galaxies in the redshift range $3 < z < 5.5$. Our analysis evaluates correlations between X-ray luminosities ($L_X$), star formation rates (SFR) and stellar metallicities ($Z_\star$) to higher redshifts and over a wider range in galaxy properties than hitherto. Using a stacking analysis performed in bins of both redshift and SFR for sources with robust spectroscopic redshifts without AGN signatures, we find convincing evolutionary trends in the ratio $L_X$/SFR to the highest redshifts probed, with a stronger trend for galaxies with lower SFRs. Combining our data with published samples at lower redshift, the evolution of $L_X$/SFR to $z\simeq5$ proceeds as $(1 + z)^{1.03 \pm 0.02}$. Using stellar metallicities derived from photospheric absorption features in our spectroscopic data, we confirm indications at lower redshifts that $L_X$/SFR is stronger for metal-poor galaxies. We use semi-analytic models to show that metallicity dependence of $L_X$/SFR alone may not be sufficient to fully explain the observed redshift evolution of X-ray emission from high-mass XRBs, particularly for galaxies with SFR $6$ may be $\gtrsim 0.25$ dex higher than previously estimated., 16 pages, 10 figures, Published in MNRAS
- Published
- 2021