Variability in tidal disruption events: Gravitationally unstable streams

Eric R. Coughlin, Chris Nixon

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


We present simulations of the tidal disruption of a solar mass star by a 106 M· black hole. These, for the first time, cover the full time evolution of the tidal disruption event, starting well before the initial encounter and continuing until more than 90% of the bound material has returned to the vicinity of the hole. Our results are compared to the analytical prediction for the rate at which tidally stripped gas falls back. We find that, for our chosen parameters, the overall scaling of the fallback rate, M fb, closely follows the canonical - t 5 3 power-law. However, our simulations also show that the self-gravity of the tidal stream, which dominates the tidal gravity of the hole at large distances, causes some of the debris to recollapse into bound fragments before returning to the hole. This causes M fb to vary significantly around the - t 5 3 average. We discuss the implications of our findings in the context of the event Swift J1644+57.

Original languageEnglish (US)
Article numberL11
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Jul 20 2015
Externally publishedYes


  • Black hole physics
  • X-rays: individual (Swift J1644+57)
  • galaxies: nuclei
  • hydrodynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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