Hyperaccretion during tidal disruption events: Weakly bound debris envelopes and jets

Eric R. Coughlin, Mitchell C. Begelman

Research output: Contribution to journalArticlepeer-review

79 Scopus citations

Abstract

After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such "zero-Bernoulli accretion" flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.

Original languageEnglish (US)
Article number82
JournalAstrophysical Journal
Volume781
Issue number2
DOIs
StatePublished - Feb 1 2014
Externally publishedYes

Keywords

  • accretion, accretion disks
  • black hole physics
  • galaxies: jets
  • galaxies: nuclei
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'Hyperaccretion during tidal disruption events: Weakly bound debris envelopes and jets'. Together they form a unique fingerprint.

Cite this