Micro-tidal disruption events by stellar compact objects and the production of ultra-long GRBs
Persistent URL
Author(s)
Perets, Hagai B.
Li, Zhuo
Lombardi, James C., Jr. (Jamie)
Milcarek, Stephen R. Jr
Date Issued
May 27, 2016
Abstract
We explore full/partial tidal disruption events (TDEs) of stars/planets by stellar compact objects (black holes (BHs) or neutron stars (NSs)), which we term micro-TDEs. Disruption of a star/planet with mass M sstarf may lead to the formation of a debris disk around the BH/NS. Efficient accretion of a fraction $({f}_{\mathrm{acc}}=0.1$ of the debris may then give rise to bright, energetic, long ({10}^{3} –{10}^{4} s), X-ray/gamma-ray flares, with total energies of up to $({f}_{\mathrm{acc}}/0.1)\times {10}^{52}\;({M}_{\star }/0.6\;{M}_{\odot })$ erg, possibly resembling ultra-long gamma-ray bursts (GRBs)/X-ray flashes (XRFs). The energy of such flares depends on the poorly constrained accretion processes. Significantly fainter flares might be produced if most of the disk mass is blown away through strong outflows. We suggest three dynamical origins for such disruptions. In the first, a star/planet is tidally disrupted following a close random encounter with a BH/NS in a dense cluster. We estimate the BH (NS) micro-TDE rates from this scenario to be a few $\times {10}^{-6}$ (a few $\times {10}^{-7}$) ${{\rm{yr}}}^{-1}$ per Milky Way galaxy. Another scenario involves the interaction of wide companions due to perturbations by stars in the field, likely producing comparable but lower rates. Finally, a third scenario involves a BH/NS that gains a natal velocity kick at birth, leading to a close encounter with a binary companion and the tidal disruption of that companion. Such events could be associated with a supernova, or even with a preceding GRB/XRF event, and would likely occur hours to days after the prompt explosion; the rates of such events could be larger than those obtained from the other scenarios, depending on the preceding complex binary stellar evolution.
Journal
The Astrophysical Journal
Department
Physics
Citation
Perets, H.B., Li, Z., Lombardi, J.C. Jr., and Milcarek, S.R. Jr. (2016). Micro-tidal disruption events by stellar compact objects and the production of ultra-long GRBs. The Astrophysical Journal 823: 1-9. doi: 10.3847/0004-637X/823/2/113
Publisher
Institute of Physics
Version of Article
Published article
DOI
10.3847/0004-637X/823/2/113
ISSN
0004-637X
e1538-4357
Rights
This article has been accepted for publication in The Astrophysical Journal ©: 2016 Hagai, Li, Lombardi, and Milcarek. Published by the Institute of Physics. All rights reserved.
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