The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type. (arXiv:2310.11496v1 [astro-ph.HE])

The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type. (arXiv:2310.11496v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bandopadhyay_A/0/1/0/all/0/1">Ananya Bandopadhyay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fancher_J/0/1/0/all/0/1">Julia Fancher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Athian_A/0/1/0/all/0/1">Aluel Athian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Indelicato_V/0/1/0/all/0/1">Valentino Indelicato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kapalanga_S/0/1/0/all/0/1">Sarah Kapalanga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kumah_A/0/1/0/all/0/1">Angela Kumah</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paradiso_D/0/1/0/all/0/1">Daniel A. Paradiso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Todd_M/0/1/0/all/0/1">Matthew Todd</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coughlin_E/0/1/0/all/0/1">Eric R. Coughlin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nixon_C/0/1/0/all/0/1">C. J. Nixon</a>

A star completely destroyed in a tidal disruption event (TDE) ignites a
luminous flare that is powered by the fallback of tidally stripped debris to a
supermassive black hole (SMBH) of mass $M_{bullet}$. We analyze two estimates
for the peak fallback rate in a TDE, one being the “frozen-in” model, which
predicts a strong dependence of the time to peak fallback rate, $t_{rm peak}$,
on both stellar mass and age, with $15textrm{ days} lesssim t_{rm peak}
lesssim 10$ yr for main sequence stars with masses $0.2le M_{star}/M_{odot}
le 5$ and $M_{bullet} = 10^6M_{odot}$. The second estimate, which postulates
that the star is completely destroyed when tides dominate the maximum stellar
self-gravity, predicts that $t_{rm peak}$ is very weakly dependent on stellar
type, with $t_{rm peak} = left(23.2pm4.0textrm{
days}right)left(M_{bullet}/10^6M_{odot}right)^{1/2}$ for $0.2le
M_{star}/M_{odot} le 5$, while $t_{rm peak} = left(29.8pm3.6textrm{
days}right)left(M_{bullet}/10^6M_{odot}right)^{1/2}$ for a Kroupa initial
mass function truncated at $1.5 M_{odot}$. This second estimate also agrees
closely with hydrodynamical simulations, while the frozen-in model is
discrepant by orders of magnitude. We conclude that (1) the time to peak
luminosity in complete TDEs is almost exclusively determined by SMBH mass, and
(2) massive-star TDEs power the largest accretion luminosities. Consequently,
(a) decades-long extra-galactic outbursts cannot be powered by complete TDEs,
including massive-star disruptions, and (b) the most highly super-Eddington
TDEs are powered by the complete disruption of massive stars, which — if
responsible for producing jetted TDEs — would explain the rarity of jetted
TDEs and their preference for young and star-forming host galaxies.

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