X-Ray Afterglows of Short Gamma-Ray Bursts: Magnetar or Fireball?
X-Ray Afterglows of Short Gamma-Ray Bursts: Magnetar or Fireball?
The origin of the X-ray afterglows of gamma-ray bursts has regularly been debated. We fit both the fireball-shock and millisecond-magnetar models of gamma-ray bursts to the X-ray data of GRB 130603B and 140903A. We use Bayesian model selection to answer the question of which model best explains the data. This is dependent on the maximum allowed non-rotating neutron star mass M TOV , which depends solely on the unknown nuclear equation of state. We show that the data for GRB 140903A favors the millisecond-magnetar model for all possible equations of state, while the data for GRB 130603B favors the millisecond-magnetar model if M TOV 2.3 M o . If M TOV ≲ 2.3 M o , the data for GRB 130603B supports the fireball-shock model. We discuss implications of this result in regards to the nuclear equation of state and the prospect of gravitational-wave emission from newly born millisecond magnetars.
gamma-ray burst: individual (GRB 140903A, GRB 130603B), stars: magnetars
Sarin, Nikhil
bfde4e6e-0c6d-4f0f-898e-7ec34b4602ef
Lasky, Paul D.
21c4d51d-89db-4dc1-b5f9-cd9835d54fad
Ashton, Greg
a8cec4b1-3c98-4b28-af2a-1e37cb3b9f2a
10 February 2019
Sarin, Nikhil
bfde4e6e-0c6d-4f0f-898e-7ec34b4602ef
Lasky, Paul D.
21c4d51d-89db-4dc1-b5f9-cd9835d54fad
Ashton, Greg
a8cec4b1-3c98-4b28-af2a-1e37cb3b9f2a
Sarin, Nikhil, Lasky, Paul D. and Ashton, Greg
(2019)
X-Ray Afterglows of Short Gamma-Ray Bursts: Magnetar or Fireball?
Astrophysical Journal, 872 (1).
(doi:10.3847/1538-4357/aaf9a0).
Abstract
The origin of the X-ray afterglows of gamma-ray bursts has regularly been debated. We fit both the fireball-shock and millisecond-magnetar models of gamma-ray bursts to the X-ray data of GRB 130603B and 140903A. We use Bayesian model selection to answer the question of which model best explains the data. This is dependent on the maximum allowed non-rotating neutron star mass M TOV , which depends solely on the unknown nuclear equation of state. We show that the data for GRB 140903A favors the millisecond-magnetar model for all possible equations of state, while the data for GRB 130603B favors the millisecond-magnetar model if M TOV 2.3 M o . If M TOV ≲ 2.3 M o , the data for GRB 130603B supports the fireball-shock model. We discuss implications of this result in regards to the nuclear equation of state and the prospect of gravitational-wave emission from newly born millisecond magnetars.
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Published date: 10 February 2019
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Funding Information: We are grateful to Antonia Rowlinson, Eric Howell, Eric Thrane, Kendall Ackley, and the anonymous reviewer for comments on the manuscript. N.S. is supported through an Australian Postgraduate Award. P.D.L. is supported through Australian Research Council Future Fellowship FT160100112 and ARC Discovery Project DP180103155. Publisher Copyright: © 2019. The American Astronomical Society. All rights reserved.
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Keywords:
gamma-ray burst: individual (GRB 140903A, GRB 130603B), stars: magnetars
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Local EPrints ID: 508013
URI: http://eprints.soton.ac.uk/id/eprint/508013
ISSN: 0004-637X
PURE UUID: bab4ef16-9587-4954-a187-afa341afef6d
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Date deposited: 09 Jan 2026 17:45
Last modified: 10 Jan 2026 05:27
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Author:
Nikhil Sarin
Author:
Paul D. Lasky
Author:
Greg Ashton
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