Tidal Disruption Events by Compact Supermassive Black Hole Binaries. (arXiv:2202.07668v3 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Ryu_T/0/1/0/all/0/1">Taeho Ryu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Trani_A/0/1/0/all/0/1">Alessandro A. Trani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leigh_N/0/1/0/all/0/1">Nathan W. C. Leigh</a>
Stars can be tidally destroyed or swallowed by supermassive black hole
binaries. Using a large number of accurate few-body simulations, we investigate
the enhancement and suppression of full and partial disruption and direct
capture events by hard supermassive black hole binaries with a wide ranges of
key parameters, i.e., the primary black hole mass ($10^{5}-10^{8}M_{odot}$),
the binary mass ratio ($10^{-3}-1$), the ratio of the binary semimajor axis to
the hardening radius ($10^{-4}-1$), the binary eccentricity ($0.0-0.9$) and the
stellar mass ($0.3-3M_{odot}$). This is a significant extension of the
parameter space compared to previous work. We show that the encounter
probabilities of all three events are well-described by the encounter cross
section, which is proportional to the pericenter distance. The probability of
full disruptions by supermassive black hole binaries can be enhanced by up to a
factor of $40-50$ or suppressed by up to a factor of $10$, relative to that by
single black holes, depending on the binary parameters. Relativistic effects
are not important for the primary black hole mass $leq 10^{7}M_{odot}$, but
can provide an additional enhancement of the full disruption probability by
less than a factor of $2-3$ for higher primary black hole masses. We provide a
fitting formula for the full disruption probability by the hard supermassive
black hole binaries that works for a wide range of parameters. We also find
that partial disruption events can occur multiple times before full disruptions
or direct captures, and their probabilities can be greater than that of full
disruption events by a factor of three. Because partial disruption events can
induce stellar spins and mass loss and change the orbits, it can significantly
affect the overall full disruption event rate and the shape of the light
curves.
Stars can be tidally destroyed or swallowed by supermassive black hole
binaries. Using a large number of accurate few-body simulations, we investigate
the enhancement and suppression of full and partial disruption and direct
capture events by hard supermassive black hole binaries with a wide ranges of
key parameters, i.e., the primary black hole mass ($10^{5}-10^{8}M_{odot}$),
the binary mass ratio ($10^{-3}-1$), the ratio of the binary semimajor axis to
the hardening radius ($10^{-4}-1$), the binary eccentricity ($0.0-0.9$) and the
stellar mass ($0.3-3M_{odot}$). This is a significant extension of the
parameter space compared to previous work. We show that the encounter
probabilities of all three events are well-described by the encounter cross
section, which is proportional to the pericenter distance. The probability of
full disruptions by supermassive black hole binaries can be enhanced by up to a
factor of $40-50$ or suppressed by up to a factor of $10$, relative to that by
single black holes, depending on the binary parameters. Relativistic effects
are not important for the primary black hole mass $leq 10^{7}M_{odot}$, but
can provide an additional enhancement of the full disruption probability by
less than a factor of $2-3$ for higher primary black hole masses. We provide a
fitting formula for the full disruption probability by the hard supermassive
black hole binaries that works for a wide range of parameters. We also find
that partial disruption events can occur multiple times before full disruptions
or direct captures, and their probabilities can be greater than that of full
disruption events by a factor of three. Because partial disruption events can
induce stellar spins and mass loss and change the orbits, it can significantly
affect the overall full disruption event rate and the shape of the light
curves.
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