Enhancement of the tidal disruption event rate in galaxies with a nuclear star cluster: from dwarfs to ellipticals. Issue 2 (7th July 2020)

• Record Type: Journal Article
• Authors: Pfister, Hugo; Volonteri, Marta; Dai, Jane Lixin; Colpi, Monica
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 497:Issue 2(2020)
• Page Start: 2276
• Page End: 2285
• Publication Date: 2020-07-07
• Subjects: galaxies: bulges -- galaxies: dwarf -- galaxies: nuclei; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa1962
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: 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.