Issue |
EAS Publications Series
Volume 61, 2013
Gamma-ray Bursts: 15 Years of GRB Afterglows – Progenitors, Environments and Host Galaxies from the Nearby to the Early Universe
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Page(s) | 95 - 102 | |
Section | Chapter II: Prompt Emission-I Observations | |
DOI | https://doi.org/10.1051/eas/1361015 | |
Published online | 22 July 2013 |
A.J. Castro-Tirado, J.Gorosabel and I.H. Park (eds)
EAS Publications Series, 61 (2013) 95-102
On the Prompt Signals of Gamma Ray Bursts
1 Department of Physics and Leung
Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University,
Taipei, Taiwan 10617 & KIPAC, SLAC, Stanford University,
CA
94035,
USA ;
e-mail: pisinchen@phys.ntu.edu.tw
2 ZEST &
Ludwig-Maximilians-Universitat Munchen, Fakultat f. Physik, am Coulombwall 1,
85748
Garching,
Germany
3 Posthumous, Department of Physics,
University of Alabama, Huntsville, AL
35899,
USA
We introduce a new model of gamma ray burst (GRB) that explains its observed prompt signals, namely, its primary quasi-thermal spectrum and high energy tail. This mechanism can be applied to either assumption of GRB progenitor: coalescence of compact objects or hypernova explosion. The key ingredients of our model are: (1) The initial stage of a GRB is in the form of a relativistic quark-gluon plasma lava; (2) The expansion and cooling of this lava results in a QCD phase transition that induces a sudden gravitational stoppage of the condensed non-relativistic baryons and form a hadrosphere; (3) Acoustic shocks and Alfven waves (magnetoquakes) that erupt in episodes from the epicenter efficiently transport the thermal energy to the hadrospheric surface and induce a rapid detachment of leptons and photons from the hadrons; (4) The detached e + e − and γ form an opaque, relativistically hot leptosphere, which expands and cools to T ~ mc2, or 0.5 MeV, where e + e − → 2γ and its reverse process becomes unbalanced, and the GRB photons are finally released; (5) The mode-conversion of Alfven waves into electromagnetic waves in the leptosphere provides a snowplow acceleration and deceleration that gives rise to both the high energy spectrum of GRB and the erosion of its thermal spectrum down to a quasi-thermal distribution. According to this model, the observed GRB photons should have a redshifted peak frequency at Ep ~ Γ(1 + β/2)mc2/(1 + z), where Γ ~ O(1) is the Lorentz factor of the bulk flow of the lava, which may be determined from the existing GRB data.
© EAS, EDP Sciences 2013