Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black Hole Leftovers: The Remnant Population from Binary Black Hole
  Mergers   The inspiral and merger of two black holes produces a remnant black hole with
mass and spin determined by the properties of its parent black holes. Using the
inferred population properties of component black holes from the first two and
a half observing runs of Advanced LIGO and Virgo, we calculate the population
properties of the leftover remnant black holes. By integrating their rate of
formation over the age of the universe, we estimate the number density of
remnant black holes today. Using simple prescriptions for the cosmic star
formation rate and black hole inspiral delay times, we determine the number
density of this leftover black hole population to be $660_{-240}^{+440}
\mathrm{Mpc}^{-3}$, corresponding to $\sim 60,000$ black hole remnants per
Milky-Way-equivalent galaxy. The mass spectrum of these remnants starts at
$\sim 10 M_\odot$ and can be approximated by a decreasing exponential with
characteristic length $\sim 15 M_\odot$, the final spin distribution is sharply
peaked at $\chi_f\sim0.7$, and the kick velocities range from tens to thousands
of km/s. These kick velocities suggest that globular clusters and nuclear star
clusters may retain up to $3_{-2}^{+3}\%$ and $46_{-15}^{+17}\%$ of their
remnant black holes, respectively, while young star clusters would only retain
a few tenths of a percent. The estimates in this work assume that none of the
remnants participate in subsequent hierarchical mergers. If hierarchical
mergers occur, the overall number density would drop accordingly and the
remnant mass distribution shape would evolve over time. This population of
leftover black holes is an inescapable result from gravitational-wave
observations of binary black-hole mergers.

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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol