The Collapse of Neutron Stars in High-Mass Binaries as the Energy Source for the Gamma-Ray Bursts

Abstract

The energy source has remained to be the great mystery in understanding of the gamma-ray bursts (GRBs) if the events are placed at cosmological distances as indicated by a number of recent observations. The currently popular models include (1)the merger of two neutron stars or a neutron star and a black hole binary and (2)the hypernova scenario of the collapse of a massive member in a close binary. Since a neutron star will inevitably collapse into a black hole if its mass exceeds the limit $M_{max}\approx 3M_{\odot }$, releasing a total binding gravitational energy of $\sim 10^{54}$ erg, we explore semi-empirically the possibility of attributing the energy source of GRB to the accretion- induced collapse of a neutron star (AICNS) in a massive X-ray binary system consisting of a neutron star and a type O/B companion. This happens because a significant mass flow of $\sim 10^{-3}$--$10^{-4}{M}_{\odot }$ yr${}^{-1}$ may be transferred onto the neutron star through the Roche-lobe overflow and primarily during the spiral-in phase when it plunges into the envelope of the companion, which may eventually lead to the AICNS before the neutron star merges with the core of the companion. In this scenario, a ``dirty'' fireball with a moderate amount of beaming is naturally expected because of the nonuniformity of the stellar matter surrounding the explosion inside the companion, and a small fraction ($\sim 0.1$) of the energy is sufficient to create the observed GRBs. In addition, the bulk of the ejecting matter of the companion star with a relatively slow expansion rate may act as the afterglow. Assuming a non-evolutionary model for galaxies, we estimate that the birthrate of the AICNS events is about 2 per day within a volume to redshift $z=1$ for an ${\Omega }_0=1$ universe, consistent with the reported GRB rate.

4 pages, no figures, emulateapj.sty, to appear in ApJ Letters, several paragraphs added, references added and updated

References in corpus (5)

• Discovery of the X-Ray Afterglow of the Gamma-Ray Burst of February 28 1997
• GRB after-glow: Supporting the cosmological fireball model, constraining parameters, and making predictions
• The optical counterpart to gamma-ray burst GRB970228 observed using the Hubble Space Telescope
• The soft X-ray afterglow of gamma ray bursts, a stringent test for the fireball model
• The afterglow of gamma ray bursts II: the cases of GRB 970228 and GRB 970508

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• Fast ejecta as a potential way to distinguish black holes from neutron stars in high-mass gravitational-wave events
• Progenitor delay-time distribution of short gamma-ray bursts: Constraints from observations
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• Binary neutron star merger offsets from their host galaxies II. Short-duration gamma-ray bursts