The impact of mass-transfer physics on the observable properties of field binary black hole populations. (arXiv:2010.16333v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Bavera_S/0/1/0/all/0/1">Simone S. Bavera</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fragos_T/0/1/0/all/0/1">Tassos Fragos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zevin_M/0/1/0/all/0/1">Michael Zevin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berry_C/0/1/0/all/0/1">Christopher P. L. Berry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marchant_P/0/1/0/all/0/1">Pablo Marchant</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Andrews_J/0/1/0/all/0/1">Jeff J. Andrews</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coughlin_S/0/1/0/all/0/1">Scott Coughlin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dotter_A/0/1/0/all/0/1">Aaron Dotter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kovlakas_K/0/1/0/all/0/1">Konstantinos Kovlakas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Misra_D/0/1/0/all/0/1">Devina Misra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Serra_Perez_J/0/1/0/all/0/1">Juan G. Serra-Perez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qin_Y/0/1/0/all/0/1">Ying Qin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rocha_K/0/1/0/all/0/1">Kyle A. Rocha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roman_Garza_J/0/1/0/all/0/1">Jaime Román-Garza</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tran_N/0/1/0/all/0/1">Nam H. Tran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zapartas_E/0/1/0/all/0/1">Emmanouil Zapartas</a>
We study the impact of mass-transfer physics on the observable properties of
binary black hole populations formed through isolated binary evolution. We
investigate the impact of mass-accretion efficiency onto compact objects and
common-envelope efficiency on the observed distributions of $chi_{eff}$,
$M_{chirp}$ and $q$. We find that low common envelope efficiency translates to
tighter orbits post common envelope and therefore more tidally spun up
second-born black holes. However, these systems have short merger timescales
and are only marginally detectable by current gravitational-waves detectors as
they form and merge at high redshifts ($zsim 2$), outside current detector
horizons. Assuming Eddington-limited accretion efficiency and that the
first-born black hole is formed with a negligible spin, we find that all
non-zero $chi_{eff}$ systems in the detectable population can come only from
the common envelope channel as the stable mass-transfer channel cannot shrink
the orbits enough for efficient tidal spin-up to take place. We find the local
rate density ($zsimeq 0.01$) for the common envelope channel is in the range
$sim 17-113~Gpc^{-3}yr^{-1}$ considering a range of $alpha_{CE} in
[0.2,5.0]$ while for the stable mass transfer channel the rate density is $sim
25~Gpc^{-3}yr^{-1}$. The latter drops by two orders of magnitude if the mass
accretion onto the black hole is not Eddington limited because conservative
mass transfer does not shrink the orbit as efficiently as non-conservative mass
transfer does. Finally, using GWTC-2 events, we constrain the lower bound of
branching fraction from other formation channels in the detected population to
be $sim 0.2$. Assuming all remaining events to be formed through either stable
mass transfer or common envelope channels, we find moderate to strong evidence
in favour of models with inefficient common envelopes.
We study the impact of mass-transfer physics on the observable properties of
binary black hole populations formed through isolated binary evolution. We
investigate the impact of mass-accretion efficiency onto compact objects and
common-envelope efficiency on the observed distributions of $chi_{eff}$,
$M_{chirp}$ and $q$. We find that low common envelope efficiency translates to
tighter orbits post common envelope and therefore more tidally spun up
second-born black holes. However, these systems have short merger timescales
and are only marginally detectable by current gravitational-waves detectors as
they form and merge at high redshifts ($zsim 2$), outside current detector
horizons. Assuming Eddington-limited accretion efficiency and that the
first-born black hole is formed with a negligible spin, we find that all
non-zero $chi_{eff}$ systems in the detectable population can come only from
the common envelope channel as the stable mass-transfer channel cannot shrink
the orbits enough for efficient tidal spin-up to take place. We find the local
rate density ($zsimeq 0.01$) for the common envelope channel is in the range
$sim 17-113~Gpc^{-3}yr^{-1}$ considering a range of $alpha_{CE} in
[0.2,5.0]$ while for the stable mass transfer channel the rate density is $sim
25~Gpc^{-3}yr^{-1}$. The latter drops by two orders of magnitude if the mass
accretion onto the black hole is not Eddington limited because conservative
mass transfer does not shrink the orbit as efficiently as non-conservative mass
transfer does. Finally, using GWTC-2 events, we constrain the lower bound of
branching fraction from other formation channels in the detected population to
be $sim 0.2$. Assuming all remaining events to be formed through either stable
mass transfer or common envelope channels, we find moderate to strong evidence
in favour of models with inefficient common envelopes.
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