{
  "id": "2107.03565",
  "version": "v1",
  "published": "2021-07-08T02:08:05.000Z",
  "updated": "2021-07-08T02:08:05.000Z",
  "title": "Population Synthesis of Black Hole Binaries with Compact Star Companions",
  "authors": [
    "Yong Shao",
    "Xiang-Dong Li"
  ],
  "comment": "21 pages, 12 figures, 1 table, submitted to ApJ after incorporating referee's comments",
  "categories": [
    "astro-ph.HE",
    "astro-ph.SR",
    "gr-qc"
  ],
  "abstract": "We perform a systematic study of merging black hole (BH) binaries with compact star (CS) companions, including black hole--white dwarf (BH--WD), black hole--neutron star (BH--NS) and black hole--black hole (BH--BH) systems. Previous studies have shown that mass transfer stability and common envelope evolution can significantly affect the formation of merging BH--CS binaries through isolated binary evolution. With detailed binary evolution simulations, we obtain easy-to-use criteria for the occurrence of the common envelope phase in mass-transferring BH binaries with a nondegenerate donor, and incorporate into population synthesis calculations. To explore the impact of possible mass gap between NSs and BHs on the properties of merging BH--CS binary population, we adopt different supernova mechanisms involving the \\textit{rapid}, \\textit{delayed} and \\textit{stochastic} prescriptions to deal with the compact remnant masses and the natal kicks. Our calculations show that there are $ \\sim 10^{5} -10^{6}$ BH--CS binaries in the Milky Way, among which dozens are observable by future space-based gravitational wave detectors. We estimate that the local merger rate density of all BH--CS systems is $ \\sim 60-200 \\,\\rm Gpc^{-3}yr^{-1}$. While there are no low-mass BHs formed via \\textit{rapid} supernovae, both \\textit{delayed} and \\textit{stochastic} prescriptions predict that $ \\sim 100\\% $/$ \\sim 70\\% $/$ \\sim 30\\% $ of merging BH--WD/BH--NS/BH--BH binaries are likely to have BH components within the mass gap.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-07-08T02:08:05.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "black hole binaries",
      "compact star companions",
      "population synthesis",
      "merging bh-cs binary",
      "mass gap"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 21,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}