The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type
| Autor: | Ananya Bandopadhyay, Julia Fancher, Aluel Athian, Valentino Indelicato, Sarah Kapalanga, Angela Kumah, Daniel A. Paradiso, Matthew Todd, Eric R. Coughlin, C. J. Nixon |
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| Jazyk: | angličtina |
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | The Astrophysical Journal Letters, Vol 961, Iss 1, p L2 (2024) |
| Druh dokumentu: | article |
| ISSN: | 2041-8213 2041-8205 |
| DOI: | 10.3847/2041-8213/ad0388 |
| Popis: | 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, t _peak , on both stellar mass and age, with 15 days ≲ t _peak ≲ 10 yr for main sequence stars with masses 0.2 ≤ M _⋆ / M _⊙ ≤ 5 and M _• = 10 ^6 M _⊙ . The second estimate, which postulates that the star is completely destroyed when tides dominate the maximum stellar self-gravity, predicts that t _peak 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 1.5 M _⊙ . 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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