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Title: Models for Gamma-Ray Bursts and Diverse Transients

Abstract

The observational diversity of ''gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic model for the central engine operating in a massive star of variable mass, differential rotation rate, and mass loss rate. Whatever that central engine may be--and here the collapsar is used as a reference point--it must be capable of generating both a narrowly collimated, highly relativistic jet to make the GRB, and a wide angle, sub-relativistic outflow responsible for exploding the star and making the supernova bright. To some extent, the two components may vary independently, so it is possible to produce a variety of jet energies and supernova luminosities. We explore, in particular, the production of low energy bursts and find a lower limit, {approx} 10{sup 48} erg s{sup -1} to the power required for a jet to escape a massive star before that star either explodes or is accreted. Lower energy bursts and ''suffocated'' bursts may be particularly prevalent when the metallicity is high, i.e., in the modern universe at low redshift.

Authors:
; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
897733
Report Number(s):
SLAC-PUB-12305
astro-ph/0701320; TRN: US200705%%313
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Submitted to Phil.Trans.Roy.Soc.Lond.
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION; INCLINATION; PRODUCTION; PROLIFERATION; ROTATION; STARS; TRANSIENTS; UNIVERSE; Astrophysics,ASTRO

Citation Formats

Woosley, S.E., /UC, Santa Cruz, Zhang, Weiqun, and /KIPAC, Menlo Park. Models for Gamma-Ray Bursts and Diverse Transients. United States: N. p., 2007. Web. doi:10.1098/rsta.2006.1997.
Woosley, S.E., /UC, Santa Cruz, Zhang, Weiqun, & /KIPAC, Menlo Park. Models for Gamma-Ray Bursts and Diverse Transients. United States. doi:10.1098/rsta.2006.1997.
Woosley, S.E., /UC, Santa Cruz, Zhang, Weiqun, and /KIPAC, Menlo Park. Wed . "Models for Gamma-Ray Bursts and Diverse Transients". United States. doi:10.1098/rsta.2006.1997. https://www.osti.gov/servlets/purl/897733.
@article{osti_897733,
title = {Models for Gamma-Ray Bursts and Diverse Transients},
author = {Woosley, S.E. and /UC, Santa Cruz and Zhang, Weiqun and /KIPAC, Menlo Park},
abstractNote = {The observational diversity of ''gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic model for the central engine operating in a massive star of variable mass, differential rotation rate, and mass loss rate. Whatever that central engine may be--and here the collapsar is used as a reference point--it must be capable of generating both a narrowly collimated, highly relativistic jet to make the GRB, and a wide angle, sub-relativistic outflow responsible for exploding the star and making the supernova bright. To some extent, the two components may vary independently, so it is possible to produce a variety of jet energies and supernova luminosities. We explore, in particular, the production of low energy bursts and find a lower limit, {approx} 10{sup 48} erg s{sup -1} to the power required for a jet to escape a massive star before that star either explodes or is accreted. Lower energy bursts and ''suffocated'' bursts may be particularly prevalent when the metallicity is high, i.e., in the modern universe at low redshift.},
doi = {10.1098/rsta.2006.1997},
journal = {Submitted to Phil.Trans.Roy.Soc.Lond.},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 17 00:00:00 EST 2007},
month = {Wed Jan 17 00:00:00 EST 2007}
}
  • Two radiation mechanisms, inverse Compton scattering (ICS) and synchrotron radiation (SR), suffice within the Cannonball (CB) model of long gamma-ray bursts (LGRBs) and X-ray flashes (XRFs) to provide a very simple and accurate description of their observed prompt emission and afterglows (AGs). Simple as they are, the two mechanisms and the burst environment generate the rich structure of the light curves at all frequencies and times. This is demonstrated for 33 selected Swift LGRBs and XRFs, which are well sampled from early until late time and faithfully represent the entire diversity of the broadband light curves of Swift LGRBs andmore » XRFs. Their prompt gamma-ray and X-ray emission is dominated by ICS of 'glory' light. During their fast decline phase, ICS is taken over by SR, which dominates their broadband AG. The pulse shape and spectral evolution of the gamma-ray peaks and the early-time X-ray flares, and even the delayed optical 'humps' in XRFs, are correctly predicted. The 'canonical' and noncanonical X-ray light curves and the chromatic behavior of the broadband AGs are well reproduced. In particular, in canonical X-ray light curves, the initial fast decline and rapid softening of the prompt emission, the transition to the plateau phase, the subsequent gradual steepening of the plateau to an asymptotic power-law decay, and the transition from chromatic to achromatic behavior of the light curves agree well with those predicted by the CB model. The Swift early-time data on XRF 060218 are inconsistent with a blackbody emission from a shock breakout through a stellar envelope. Instead, they are well described by ICS of glory light by a jet breaking out from SN2006aj.« less
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  • The component parts of gamma-ray burst models based on neutron starquakes are assessed. The requirements for, and the properties of, neutron starquakes are reviewed. The coupling of seismic waves to Alfven waves is evaluated and the behavior of Alfven waves in the magnetosphere is investigated. An attempt is made to identify the principal sources of free energy in the interiors of old neutron stars. 31 refs.