2024ApJ...961L...2B -
Astrophys. J., 961, L2 (2024/January-3)
The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type.
BANDOPADHYAY A., FANCHER J., ATHIAN A., INDELICATO V., KAPALANGA S., KUMAH A., PARADISO D.A., TODD M., COUGHLIN E.R. and NIXON C.J.
Abstract (from CDS):
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•. 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, tpeak, on both stellar mass and age, with 15 days ≲ tpeak ≲ 10 yr for main sequence stars with masses 0.2 ≤ M⋆/M⊙ ≤ 5 and M• = 106M⊙. The second estimate, which postulates that the star is completely destroyed when tides dominate the maximum stellar self-gravity, predicts that tpeak is very weakly dependent on stellar type, with ${t}_{\mathrm{peak}}=\left(23.2\pm 4.0\,{\rm{days}}\right){\left({M}_{\bullet }/{10}^{6}{M}_{\odot }\right)}^{1/2}$ for 0.2 ≤ M⋆/M⊙ ≤ 5, while ${t}_{\mathrm{peak}}\,=\left(29.8\pm 3.6\,{\rm{days}}\right){\left({M}_{\bullet }/{10}^{6}{M}_{\odot }\right)}^{1/2}$ for a Kroupa initial mass function truncated at 1.5M⊙. 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.
Abstract Copyright:
© 2024. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Astrophysical black holes - Supermassive black holes - Black hole physics - Hydrodynamics - Tidal disruption
Simbad objects:
6
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