Jet and disc luminosities in tidal disruption events

Tsvi Piran, Aleksander Şadowski*, Alexander Tchekhovskoy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Tidal disruption events (TDEs) explore the whole range of accretion rates and configurations. A challenging question is what the corresponding light curves of these events are. We explore numerically the disc luminosity and the conditions within the inner region of the disc using a fully general relativistic slim disc model. Those conditions determine the magnitude of the magnetic field that engulfs the black hole and this, in turn, determines the Blandford-Znajek jet power. We estimate this power in two different ways and show that they are self-consistent. We find, as expected earlier from analytic arguments, that neither the disc luminosity nor the jet power follows the accretion rate throughout the disruption event. The disc luminosity varies only logarithmically with the accretion rate at super-Eddington luminosities. The jet power follows initially the accretion rate but remains constant after the transition from superto sub-Eddington. At lower accretion rates at the end of the magnetically arrested disc (MAD) phase, the disc becomes thin and the jet may stop altogether. These new estimates of the jet power and disc luminosity that do not simply follow the mass fallback rate should be taken into account when searching for TDEs and analysing light curves of TDE candidates. Identification of some of the above-mentioned transitions may enable us to estimate better TDE parameters.

Original languageEnglish (US)
Pages (from-to)157-165
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jul 24 2015


  • Accretion, accretion discs
  • Black hole physics
  • Galaxies: jets
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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