Impact of Massive Binary Star and Cosmic Evolution on Gravitational Wave Observations I: Black Hole – Neutron Star Mergers. (arXiv:2103.02608v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Broekgaarden_F/0/1/0/all/0/1">Floor S. Broekgaarden</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berger_E/0/1/0/all/0/1">Edo Berger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Neijssel_C/0/1/0/all/0/1">Coenraad J. Neijssel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vigna_Gomez_A/0/1/0/all/0/1">Alejandro Vigna-Gómez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chattopadhyay_D/0/1/0/all/0/1">Debatri Chattopadhyay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stevenson_S/0/1/0/all/0/1">Simon Stevenson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chruslinska_M/0/1/0/all/0/1">Martyna Chruslinska</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Justham_S/0/1/0/all/0/1">Stephen Justham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mink_S/0/1/0/all/0/1">Selma E. de Mink</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mandel_I/0/1/0/all/0/1">Ilya Mandel</a>
Mergers of black hole-neutron star (BHNS) binaries are expected to be
observed by gravitational wave (GW) detectors in the coming years. Such
observations will not only provide confirmation that these systems exist, but
will also give unique insights into the death and lives of massive (binary)
stars and their possible association with gamma-ray bursts, r-process
enrichment, and kilonovae. Here we present binary population synthesis of
isolated BHNS systems in order to predict their merger rate and characteristics
for ground-based GW observatories. We present the results for 420 different
model permutations that explore key uncertainties in our assumptions about
massive binary star evolution (e.g., mass transfer, common-envelope evolution,
supernovae), and in our assumptions for the metallicity-specific star formation
rate density, and characterize their relative impacts on our predictions. We
predict intrinsic local BHNS merger rates in the range $mathcal{R}_{rm{m}}^0
approx 4$-$830,rm{Gpc}^{-3},rm{yr}^{-1}$ and detected rates in the range
$mathcal{R}_{rm{det}} approx 1$-$180, rm{yr}^{-1}$ for a GW network
consisting of LIGO, Virgo and KAGRA at design sensitivity. We find that the
binary evolution and metallicity-specific star formation rate density each
impact the predicted merger rates by order $mathcal{O}(10)$. We also present
predictions for the GW detected BHNS merger properties and find that all 420
model variations predict that $lesssim 5%$ of the BHNS mergers have BH masses
$gtrsim 18,M_{odot}$, total masses $gtrsim 20,M_{odot}$, chirp masses
$gtrsim 5.5,M_{odot}$, mass ratios $gtrsim 12$ or $lesssim 2$. Moreover,
we find that massive NSs $ > 2,M_{odot}$ are expected to be commonly detected
in BHNS mergers in almost all our model variations. Finally, a wide range of
$sim$ 0%-70% of the BHNS mergers are predicted to eject mass during the
merger.
Mergers of black hole-neutron star (BHNS) binaries are expected to be
observed by gravitational wave (GW) detectors in the coming years. Such
observations will not only provide confirmation that these systems exist, but
will also give unique insights into the death and lives of massive (binary)
stars and their possible association with gamma-ray bursts, r-process
enrichment, and kilonovae. Here we present binary population synthesis of
isolated BHNS systems in order to predict their merger rate and characteristics
for ground-based GW observatories. We present the results for 420 different
model permutations that explore key uncertainties in our assumptions about
massive binary star evolution (e.g., mass transfer, common-envelope evolution,
supernovae), and in our assumptions for the metallicity-specific star formation
rate density, and characterize their relative impacts on our predictions. We
predict intrinsic local BHNS merger rates in the range $mathcal{R}_{rm{m}}^0
approx 4$-$830,rm{Gpc}^{-3},rm{yr}^{-1}$ and detected rates in the range
$mathcal{R}_{rm{det}} approx 1$-$180, rm{yr}^{-1}$ for a GW network
consisting of LIGO, Virgo and KAGRA at design sensitivity. We find that the
binary evolution and metallicity-specific star formation rate density each
impact the predicted merger rates by order $mathcal{O}(10)$. We also present
predictions for the GW detected BHNS merger properties and find that all 420
model variations predict that $lesssim 5%$ of the BHNS mergers have BH masses
$gtrsim 18,M_{odot}$, total masses $gtrsim 20,M_{odot}$, chirp masses
$gtrsim 5.5,M_{odot}$, mass ratios $gtrsim 12$ or $lesssim 2$. Moreover,
we find that massive NSs $ > 2,M_{odot}$ are expected to be commonly detected
in BHNS mergers in almost all our model variations. Finally, a wide range of
$sim$ 0%-70% of the BHNS mergers are predicted to eject mass during the
merger.
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