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Title: SHORT GAMMA-RAY BURSTS FROM THE MERGER OF TWO BLACK HOLES

Short gamma-ray bursts (GRBs) are explosions of cosmic origins believed to be associated with the merger of two compact objects, either two neutron stars or a neutron star and a black hole (BH). The presence of at least one neutron star has long been thought to be an essential element of the model: its tidal disruption provides the needed baryonic material whose rapid accretion onto the post-merger BH powers the burst. The recent tentative detection by the Fermi satellite of a short GRB in association with the gravitational wave signal GW150914 produced by the merger of two BHs has challenged this standard paradigm. Here, we show that the evolution of two high-mass, low-metallicity stars with main-sequence rotational speeds a few tens of percent of the critical speed eventually undergoing a weak supernova explosion can produce a short GRB. The outer layers of the envelope of the last exploding star remain bound and circularize at large radii. With time, the disk cools and becomes neutral, suppressing the magnetorotational instability, and hence the viscosity. The disk remains “long-lived dead” until tidal torques and shocks during the pre-merger phase heat it up and re-ignite accretion, rapidly consuming the disk and powering the shortmore » GRB.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794 (United States)
  2. Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, OR 97331 (United States)
  3. Physics Department, University of Trento, via Sommarive 14, I-38123 Trento (Italy)
Publication Date:
OSTI Identifier:
22518489
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 821; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BARYONS; BLACK HOLES; COSMIC GAMMA BURSTS; DETECTION; GRAVITATIONAL WAVES; LAYERS; MASS; METALLICITY; NEUTRON STARS; SATELLITES; TORQUE; VISCOSITY