High-resolution calculations of merging neutron stars - III. Gamma-ray bursts
(2003) In Monthly Notices of the Royal Astronomical Society 345. p.1077-1090- Abstract
- Recent three-dimensional, high-resolution simulations of neutron star coalescences are analysed to assess whether short gamma-ray bursts (GRBs) could originate from such encounters. The two most popular modes of energy extraction - namely the annihilation of and magnetohydrodynamic processes - are explored in order to investigate their viability in launching GRBs. We find that annihilation can provide the necessary stresses to drive a highly relativistic expansion. However, unless the outflow is beamed into less than 1 per cent of the solid angle, this mechanism may fail to explain the apparent isotropized energies implied for short GRBs at cosmological distances. We argue that the energetic, neutrino-driven wind that accompanies the... (More)
- Recent three-dimensional, high-resolution simulations of neutron star coalescences are analysed to assess whether short gamma-ray bursts (GRBs) could originate from such encounters. The two most popular modes of energy extraction - namely the annihilation of and magnetohydrodynamic processes - are explored in order to investigate their viability in launching GRBs. We find that annihilation can provide the necessary stresses to drive a highly relativistic expansion. However, unless the outflow is beamed into less than 1 per cent of the solid angle, this mechanism may fail to explain the apparent isotropized energies implied for short GRBs at cosmological distances. We argue that the energetic, neutrino-driven wind that accompanies the merger event will have enough pressure to provide adequate collimation to the -annihilation-driven jet, thereby comfortably satisfying constraints on event rate and apparent luminosity. We also assess magnetic mechanisms to transform the available energy into a GRB. If the central object does not collapse immediately into a black hole, it will be convective and it is expected to act as an effective large scale dynamo, amplifying the seed magnetic fields to a few times 1017 G within a small fraction of a second. The associated spindown time-scale is 0.2 s, coinciding with the typical duration of a short GRB. The efficiencies of the various assessed magnetic processes are high enough to produce isotropized luminosities in excess of 1052 erg s-1 even without beaming. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/768132
- author
- Rosswog, S. ; Ramirez-Ruiz, E. and Davies, Melvyn B LU
- publishing date
- 2003
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- dense matter - hydrodynamics - neutrinos - methods: numerical - stars: neutron - gamma-rays: bursts
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 345
- pages
- 1077 - 1090
- publisher
- Oxford University Press
- external identifiers
-
- scopus:0242425047
- ISSN
- 1365-2966
- DOI
- 10.1046/j.1365-2966.2003.07032.x
- language
- English
- LU publication?
- no
- id
- e3e25e86-e68a-4ee2-921d-8cc85b0fa85c (old id 768132)
- date added to LUP
- 2016-04-04 11:23:30
- date last changed
- 2022-04-24 00:35:30
@article{e3e25e86-e68a-4ee2-921d-8cc85b0fa85c,
abstract = {{Recent three-dimensional, high-resolution simulations of neutron star coalescences are analysed to assess whether short gamma-ray bursts (GRBs) could originate from such encounters. The two most popular modes of energy extraction - namely the annihilation of and magnetohydrodynamic processes - are explored in order to investigate their viability in launching GRBs. We find that annihilation can provide the necessary stresses to drive a highly relativistic expansion. However, unless the outflow is beamed into less than 1 per cent of the solid angle, this mechanism may fail to explain the apparent isotropized energies implied for short GRBs at cosmological distances. We argue that the energetic, neutrino-driven wind that accompanies the merger event will have enough pressure to provide adequate collimation to the -annihilation-driven jet, thereby comfortably satisfying constraints on event rate and apparent luminosity. We also assess magnetic mechanisms to transform the available energy into a GRB. If the central object does not collapse immediately into a black hole, it will be convective and it is expected to act as an effective large scale dynamo, amplifying the seed magnetic fields to a few times 1017 G within a small fraction of a second. The associated spindown time-scale is 0.2 s, coinciding with the typical duration of a short GRB. The efficiencies of the various assessed magnetic processes are high enough to produce isotropized luminosities in excess of 1052 erg s-1 even without beaming.}},
author = {{Rosswog, S. and Ramirez-Ruiz, E. and Davies, Melvyn B}},
issn = {{1365-2966}},
keywords = {{dense matter - hydrodynamics - neutrinos - methods: numerical - stars: neutron - gamma-rays: bursts}},
language = {{eng}},
pages = {{1077--1090}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{High-resolution calculations of merging neutron stars - III. Gamma-ray bursts}},
url = {{http://dx.doi.org/10.1046/j.1365-2966.2003.07032.x}},
doi = {{10.1046/j.1365-2966.2003.07032.x}},
volume = {{345}},
year = {{2003}},
}