Population Properties of Compact Objects from the Second LIGO–Virgo Gravitational-Wave Transient Catalog
抄録
<jats:title>Abstract</jats:title> <jats:p>We report on the population of 47 compact binary mergers detected with a false-alarm rate of <<jats:inline-formula> <jats:tex-math> <?CDATA $1\,{\mathrm{yr}}^{-1}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> in the second LIGO–Virgo Gravitational-Wave Transient Catalog. We observe several characteristics of the merging binary black hole (BBH) population not discernible until now. First, the primary mass spectrum contains structure beyond a power law with a sharp high-mass cutoff; it is more consistent with a broken power law with a break at <jats:inline-formula> <jats:tex-math> <?CDATA ${39.7}_{-9.1}^{+20.3}\,\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> or a power law with a Gaussian feature peaking at <jats:inline-formula> <jats:tex-math> <?CDATA ${33.1}_{-5.6}^{+4.0}\,\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> (90% credible interval). While the primary mass distribution must extend to <jats:inline-formula> <jats:tex-math> <?CDATA $\sim 65\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> or beyond, only <jats:inline-formula> <jats:tex-math> <?CDATA ${2.9}_{-1.7}^{+3.5} \% $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn5.gif" xlink:type="simple" /> </jats:inline-formula> of systems have primary masses greater than <jats:inline-formula> <jats:tex-math> <?CDATA $45\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn6.gif" xlink:type="simple" /> </jats:inline-formula>. Second, we find that a fraction of BBH systems have component spins misaligned with the orbital angular momentum, giving rise to precession of the orbital plane. Moreover, <jats:inline-formula> <jats:tex-math> <?CDATA $12$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn7.gif" xlink:type="simple" /> </jats:inline-formula>%–<jats:inline-formula> <jats:tex-math> <?CDATA $44$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn8.gif" xlink:type="simple" /> </jats:inline-formula>% of BBH systems have spins tilted by more than 90°, giving rise to a negative effective inspiral spin parameter, <jats:inline-formula> <jats:tex-math> <?CDATA ${\chi }_{\mathrm{eff}}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn9.gif" xlink:type="simple" /> </jats:inline-formula>. Under the assumption that such systems can only be formed by dynamical interactions, we infer that between 25% and 93% of BBHs with nonvanishing <jats:inline-formula> <jats:tex-math> <?CDATA $| {\chi }_{\mathrm{eff}}| \gt 0.01$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn10.gif" xlink:type="simple" /> </jats:inline-formula> are dynamically assembled. Third, we estimate merger rates, finding <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal R }}_{\mathrm{BBH}}={23.9}_{-8.6}^{+14.3}\,\,{\mathrm{Gpc}}^{-3}\,{\mathrm{yr}}^{-1}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn11.gif" xlink:type="simple" /> </jats:inline-formula> for BBHs and <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal R }}_{\mathrm{BNS}}={320}_{-240}^{+490}\,\,{\mathrm{Gpc}}^{-3}\,{\mathrm{yr}}^{-1}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn12.gif" xlink:type="simple" /> </jats:inline-formula> for binary neutron stars. We find that the BBH rate likely increases with redshift (<jats:inline-formula> <jats:tex-math> <?CDATA $85 \% $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn13.gif" xlink:type="simple" /> </jats:inline-formula> credibility) but not faster than the star formation rate (<jats:inline-formula> <jats:tex-math> <?CDATA $86 \% $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjlabe949ieqn14.gif" xlink:type="simple" /> </jats:inline-formula> credibility). Additionally, we examine recent exceptional events in the context of our population models, finding that the asymmetric masses of GW190412 and the high component masses of GW190521 are consistent with our models, but the low secondary mass of GW190814 makes it an outlier.</jats:p>
収録刊行物
-
- The Astrophysical Journal Letters
-
The Astrophysical Journal Letters 913 (1), L7-, 2021-05-01
American Astronomical Society
- Tweet
詳細情報 詳細情報について
-
- CRID
- 1360013168755514496
-
- ISSN
- 20418213
- 20418205
-
- データソース種別
-
- Crossref
- KAKEN