Abstract
It is now established that a thermal emission component plays a major role in shaping the prompt spectra of a non-negligible fraction of gamma-ray bursts (GRBs). By studying the properties of this component in a sample of 47 GRBs, we deduce that the Lorentz factor is 102 Γ 103, with mean value Γ 370. The acceleration radius r0 span a wide range, 106.5 r0 109.5 cm, with mean value r0 108 cm. This is higher than the gravitational radius of 10 M black hole by a factor of ≈ 30. We argue that this result provides an indirect evidence for jet propagation inside a massive star, and suggests the existence of recollimation shocks that take place at this radius. We further show that sub-photospheric dissipation of the jet kinetic energy provides a self-consistent, fully physically motivated model that can fit a wide range of GRB spectra. The leading radiative process is Comptonization of the thermal component, and synchrotron emission is sub-dominant. We create a DREAM (Dissipation with Radiative Emission as a Table Model) table model for XSPEC, and show how this model can describe different types of GRB spectra.
Original language | English |
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Title of host publication | 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, Proceedings |
Editors | Massimo Bianchi, Robert T Jantzen, Remo Ruffini, Remo Ruffini |
Publisher | World Scientific Publishing Co. Pte Ltd |
Pages | 2943-2949 |
Number of pages | 7 |
ISBN (Electronic) | 9789813226593 |
DOIs | |
State | Published - 2018 |
Externally published | Yes |
Event | 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Rome, Italy Duration: 12 Jul 2015 → 18 Jul 2015 |
Publication series
Name | 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, Proceedings |
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Conference
Conference | 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories |
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Country/Territory | Italy |
City | Rome |
Period | 12/07/15 → 18/07/15 |
Bibliographical note
Publisher Copyright:Copyright © 2018 by the Editors.All rights reserved.
Keywords
- Gamma-rays: bursts
- Hydrodynamics
- Radiation mechanism: non-thermal
- Radiation mechanism: thermal