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Title: Evolution of accretion disks in tidal disruption events

Abstract

During a stellar tidal disruption event (TDE), an accretion disk forms as stellar debris returns to the disruption site and circularizes. Rather than being confined within the circularizing radius, the disk can spread to larger radii to conserve angular momentum. A spreading disk is a source of matter for re-accretion at rates that may exceed the later stellar fallback rate, although a disk wind can suppress its contribution to the central black hole accretion rate. A spreading disk is detectible through a break in the central accretion rate history or, at longer wavelengths, by its own emission. We model the evolution of TDE disk size and accretion rate by accounting for the time-dependent fallback rate, for the influence of wind losses in the early advective stage, and for the possibility of thermal instability for accretion rates intermediate between the advection-dominated and gas-pressure-dominated states. The model provides a dynamic basis for modeling TDE light curves. All or part of a young TDE disk will precess as a solid body because of the Lense-Thirring effect, and precession may manifest itself as a quasi-periodic modulation of the light curve. The precession period increases with time. Applying our results to the jetted TDE candidatemore » Swift J1644+57, whose X-ray light curve shows numerous quasi-periodic dips, we argue that the data best fit a scenario in which a main-sequence star was fully disrupted by an intermediate mass black hole on an orbit significantly inclined from the black hole equator, with the apparent jet shutoff at t = 500 days corresponding to a disk transition from the advective state to the gas-pressure-dominated state.« less

Authors:
 [1]
  1. Current address: Racah Institute of Physics, Hebrew University of Jerusalem, Israel. (Israel)
Publication Date:
OSTI Identifier:
22357296
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 784; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCOUNTING; ACCRETION DISKS; ADVECTION; ANGULAR MOMENTUM; BLACK HOLES; EMISSION; EVOLUTION; GALAXY NUCLEI; GRAVITATION; INSTABILITY; MAIN SEQUENCE STARS; ORBITS; PERIODICITY; PRECESSION; SIMULATION; TIME DEPENDENCE; VISIBLE RADIATION; WAVELENGTHS; X RADIATION

Citation Formats

Shen, Rong-Feng, and Matzner, Christopher D., E-mail: rf.shen@mail.huji.ac.il, E-mail: matzner@astro.utoronto.ca. Evolution of accretion disks in tidal disruption events. United States: N. p., 2014. Web. doi:10.1088/0004-637X/784/2/87.
Shen, Rong-Feng, & Matzner, Christopher D., E-mail: rf.shen@mail.huji.ac.il, E-mail: matzner@astro.utoronto.ca. Evolution of accretion disks in tidal disruption events. United States. https://doi.org/10.1088/0004-637X/784/2/87
Shen, Rong-Feng, and Matzner, Christopher D., E-mail: rf.shen@mail.huji.ac.il, E-mail: matzner@astro.utoronto.ca. 2014. "Evolution of accretion disks in tidal disruption events". United States. https://doi.org/10.1088/0004-637X/784/2/87.
@article{osti_22357296,
title = {Evolution of accretion disks in tidal disruption events},
author = {Shen, Rong-Feng and Matzner, Christopher D., E-mail: rf.shen@mail.huji.ac.il, E-mail: matzner@astro.utoronto.ca},
abstractNote = {During a stellar tidal disruption event (TDE), an accretion disk forms as stellar debris returns to the disruption site and circularizes. Rather than being confined within the circularizing radius, the disk can spread to larger radii to conserve angular momentum. A spreading disk is a source of matter for re-accretion at rates that may exceed the later stellar fallback rate, although a disk wind can suppress its contribution to the central black hole accretion rate. A spreading disk is detectible through a break in the central accretion rate history or, at longer wavelengths, by its own emission. We model the evolution of TDE disk size and accretion rate by accounting for the time-dependent fallback rate, for the influence of wind losses in the early advective stage, and for the possibility of thermal instability for accretion rates intermediate between the advection-dominated and gas-pressure-dominated states. The model provides a dynamic basis for modeling TDE light curves. All or part of a young TDE disk will precess as a solid body because of the Lense-Thirring effect, and precession may manifest itself as a quasi-periodic modulation of the light curve. The precession period increases with time. Applying our results to the jetted TDE candidate Swift J1644+57, whose X-ray light curve shows numerous quasi-periodic dips, we argue that the data best fit a scenario in which a main-sequence star was fully disrupted by an intermediate mass black hole on an orbit significantly inclined from the black hole equator, with the apparent jet shutoff at t = 500 days corresponding to a disk transition from the advective state to the gas-pressure-dominated state.},
doi = {10.1088/0004-637X/784/2/87},
url = {https://www.osti.gov/biblio/22357296}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 784,
place = {United States},
year = {Tue Apr 01 00:00:00 EDT 2014},
month = {Tue Apr 01 00:00:00 EDT 2014}
}