{
  "id": "2004.13033",
  "version": "v1",
  "published": "2020-04-27T18:00:01.000Z",
  "updated": "2020-04-27T18:00:01.000Z",
  "title": "Connecting the metallicity dependence and redshift evolution of high-mass X-ray binaries",
  "authors": [
    "Francesca M. Fornasini",
    "Francesca Civano",
    "Hyewon Suh"
  ],
  "comment": "13 pages, 7 figures, 2 tables",
  "categories": [
    "astro-ph.HE",
    "astro-ph.GA"
  ],
  "abstract": "The integrated X-ray luminosity ($L_{\\mathrm{X}}$) of high-mass X-ray binaries (HMXBs) in a galaxy is correlated with its star formation rate (SFR), and the normalization of this correlation increases with redshift. Population synthesis models suggest that the redshift evolution of $L_{\\mathrm{X}}$/SFR is driven by the metallicity ($Z$) dependence of HMXBs, and the first direct evidence of this connection was recently presented using galaxies at $z\\sim2$. To confirm this result with more robust measurements and better constrain the $L_{\\mathrm{X}}$-SFR-$Z$ relation, we have studied the $Z$ dependence of $L_{\\mathrm{X}}$/SFR at lower redshifts. Using samples of star-forming galaxies at $z=0.1-0.9$ with optical spectra from the hCOSMOS and zCOSMOS surveys, we stacked \\textit{Chandra} data from the COSMOS Legacy survey to measure the average $L_{\\mathrm{X}}$/SFR as a function of $Z$ in three redshift ranges: $z=0.1-0.25$, $0.25-0.4$, and $0.5-0.9$. We find no significant variation of the $L_{\\mathrm{X}}$-SFR-$Z$ relation with redshift. Our results provide further evidence that the $Z$ dependence of HMXBs is responsible for the redshift evolution of $L_{\\mathrm{X}}$/SFR. Combining all available $z>0$ measurements together, we derive a best-fitting $L_{\\mathrm{X}}$-SFR-$Z$ relation and assess how different population synthesis models describe the data. These results provide the strongest constraints to date on the $L_{\\mathrm{X}}$-SFR-$Z$ relation in the range of $8.0<$12+log(O/H)$<9.0$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-04-27T18:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high-mass x-ray binaries",
      "redshift evolution",
      "metallicity dependence",
      "population synthesis models",
      "star formation rate"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}