Revisiting the Rates and Demographics of Tidal Disruption Events: Effects of the Disk Formation Efficiency

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  • Thomas Hong Tsun Wong
  • Hugo Pfister
  • Lixin Dai

Tidal disruption events (TDEs) are valuable probes of the demographics of supermassive black holes as well as the dynamics and population of stars in the centers of galaxies. In this Letter, we focus on studying how debris disk formation and circularization processes can impact the possibility of observing prompt flares in TDEs. First, we investigate how the efficiency of disk formation is determined by the key parameters, namely, the black hole mass MBH, the stellar mass ma, and the orbital penetration parameter ss that quantifies how close the disrupted star would orbit around the black hole. Then we calculate the intrinsic differential TDE rate as a function of these three parameters. Combining these two results, we find that the rates of TDEs with prompt disk formation are significantly suppressed around lighter black holes, which provides a plausible explanation for why the observed TDE host black hole mass distribution peaks between 106 and 107Me. Therefore, the consideration of disk formation efficiency is crucial for recovering the intrinsic black hole demographics from TDEs. Furthermore, we find that the efficiency of the disk formation process also impacts the distributions of both stellar orbital penetration parameter and stellar mass observed in TDEs.

Original languageEnglish
Article number19
JournalAstrophysical Journal Letters
Volume927
Issue number1
Number of pages14
ISSN2041-8205
DOIs
Publication statusPublished - 1 Mar 2022

    Research areas

  • BLACK-HOLE MASSES, STARS, EMISSION, STELLAR

ID: 302554059