Enhancement of the tidal disruption event rate in galaxies with a nuclear star cluster: from dwarfs to ellipticals
Résumé
We compute the tidal disruption event (TDE) rate around local massive black holes (MBHs) with masses as low as |$2.5\times 10^4\, \mathrm{M}_{\odot }$|, thus probing the dwarf regime for the first time. We select a sample of 37 galaxies for which we have the surface stellar density profile, a dynamical estimate of the mass of the MBH, and 6 of which, including our Milky Way, have a resolved nuclear star cluster (NSC). For the Milky Way, we find a total TDE rate of |${\sim}10^{-4}\, \mathrm{yr}^{-1}$| when taking the NSC in account, and |${\sim}10^{-7} \, \mathrm{yr}^{-1}$| otherwise. TDEs are mainly sourced from the NSC for light (|${\lt}3\times 10^{10}\, \mathrm{M}_{\odot }$|) galaxies, with a rate of few |$10^{-5}\, \mathrm{yr}^{-1}$|, and an enhancement of up to two orders of magnitude compared to non-nucleated galaxies. We create a mock population of galaxies using different sets of scaling relations to explore trends with galaxy mass, taking into account the nucleated fraction of galaxies. Overall, we find a rate of few |$10^{-5}\, \mathrm{yr}^{-1}$| which drops when galaxies are more massive than |$10^{11}\, \mathrm{M}_{\odot }$| and contain MBHs swallowing stars whole and resulting in no observable TDE.
Domaines
Astrophysique [astro-ph]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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