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Synchrotron Emission in Small-scale Magnetic Fields as a Possible Explanation for Prompt Emission Spectra of Gamma-ray Bursts
| Content Provider | Semantic Scholar |
|---|---|
| Author | Zhang, Bing |
| Copyright Year | 2006 |
| Abstract | Synchrotron emission is believed to be a major radiation mechanism during gamma-ray bursts’ (GRBs) prompt emission phase. A significant drawback of this assumption is that the theoretical predicted spectrum, calculated within the framework of the ‘‘internal shocks’’ scenario using the standard assumption that the magnetic field maintains a steady value throughout the shocked region, leads to a slope F / 1=2 below 100 keV, which is in contradiction to the much harder spectra observed. This is due to the electron cooling time being much shorter than the dynamical time. In order to overcome this problem,we propose here that themagnetic field created by the internal shocks decays on a length scale much shorter than the comoving width of the plasma. We show that under this assumption synchrotron radiation can reproduce the observed prompt emission spectra of themajority of the bursts.We calculate the required decay length of the magnetic field, and find it to be 104Y10 cm (equivalent to 10Y10 skin depths), much shorter than the characteristic comovingwidth of the plasma, 3 ; 10 cm.We implement our model to the case of GRB 050820A, where a break atP4 keVwas observed, and show that this break can be explained by synchrotron self-absorption.We discuss the consequences of the small-scale magnetic field scenario on current models of magnetic field generation in shock waves. Subject headinggs: gamma rays: bursts — gamma rays: theory — magnetic fields — plasmas — radiation mechanisms: nonthermal Online material: color figures |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.physics.unlv.edu/~bzhang/pz06b.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/astro-ph/0605641v2.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Computer cooling Cool - action Egoism Electron GRB10 wt Allele GZMB wt Allele Interferon Type II Kiloelectronvolt Lindane Magnetic Fields Plasma Active RCA Spectra 70 Radiation Shock Significant figures Synchrotrons width |
| Content Type | Text |
| Resource Type | Article |
