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The Evolution of Normal Galaxy X-Ray Emission Through Cosmic History: Constraints from the 6 MS Chandra Deep Field-SouthWe present measurements of the evolution of normal-galaxy X-ray emission from z (is) approx. 0-7 using local galaxies and galaxy samples in the approx. 6 Ms Chandra Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are observed at rest-frame energies above 2 keV, where the emission is expected to be dominated by X-ray binary (XRB) populations; however, hot gas is expected to provide small contributions to the observed-frame (is) less than 1 keV emission at z (is) less than 1. We show that a single scaling relation between X-ray luminosity (L(sub x)) and star-formation rate (SFR) literature, is insufficient for characterizing the average X-ray emission at all redshifts. We establish that scaling relations involving not only SFR, but also stellar mass and redshift, provide significantly improved characterizations of the average X-ray emission from normal galaxy populations at z (is) approx. 0-7. We further provide the first empirical constraints on the redshift evolution of X-ray emission from both low-mass XRB (LMXB) and high-mass XRB (HMXB) populations and their scalings with stellar mass and SFR, respectively. We find L2 -10 keV(LMXB)/stellar mass alpha (1+z)(sub 2-3) and L2 -10 keV(HMXB)/SFR alpha (1+z), and show that these relations are consistent with XRB population-synthesis model predictions, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. We discuss how emission from XRBs could provide an important source of heating to the intergalactic medium in the early universe, exceeding that of active galactic nuclei.
Document ID
Document Type
Reprint (Version printed in journal)
Lehmer, B. D. (Arkansas Univ. Fayetteville, AR, United States)
Basu-Zych, A. R. (Maryland Univ. Baltimore County Baltimore, MD, United States)
Mineo, S. (Max-Planck-Inst. fuer Astrophysik Garching, Germany)
Brandt, W. N. (Pennsylvania State Univ. University Park, PA, United States)
Eurfrasio, R. T. (Johns Hopkins Univ. Baltimore, MD, United States)
Fragos, T. (Geneva Univ. Geneva, Switzerland)
Hornschemeier, A. E. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Lou, B. (Pennsylvania State Univ. University Park, PA, United States)
Xue, Y. Q. (China Scientific and Technical Univ. Anhui, China)
Bauer, F. E. (Pontificia Univ. Catolica de Chile Santiago, Chile)
Gilfanov, M. (Max-Planck-Inst. fuer Astrophysik Garching, Germany)
Date Acquired
April 14, 2017
Publication Date
June 24, 2016
Publication Information
Publication: The Astrophysical Journal
Volume: 825
Issue: 1
ISSN: 0004-637X
Subject Category
Report/Patent Number
Funding Number(s)
Distribution Limits
X-rays: binaries
galaxies: evolution