Microphysics and dynamics of the gamma-ray burst 121024A

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21670%2F16%3A00308305" target="_blank" >RIV/68407700:21670/16:00308305 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1051/0004-6361/201526260" target="_blank" >http://dx.doi.org/10.1051/0004-6361/201526260</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201526260" target="_blank" >10.1051/0004-6361/201526260</a>

Result language

angličtina

Original language name

Microphysics and dynamics of the gamma-ray burst 121024A

Original language description

Aims. The aim of the study is to constrain the physics of gamma-ray bursts (GRBs) by analysing the multi-wavelength afterglow data set of GRB 121024A that covers the full range from radio to X-rays. Methods. Using multi-epoch broad-band observations of the GRB 121024A afterglow, we measured the three characteristic break frequencies of the synchrotron spectrum. We used six epochs of combined XRT and GROND data to constrain the temporal slopes, the dust extinction, the X-ray absorption, and the spectral slope with high accuracy. Two more epochs of combined data from XRT, GROND, APEX, CARMA, and EVLA were used to set constraints on the break frequencies and therefore on the micro-physical and dynamical parameters. Results. The XRT and GROND light curves show a simultaneous and achromatic break at around 49 ks. As a result, the crossing of the synchrotron cooling break is no suitable explanation for the break in the light curve. The multi-wavelength data allow us to test two plausible scenarios explaining the break: a jet break, and the end of energy injection. The jet-break scenario requires a hard electron spectrum, a very low cooling break frequency, and a non-spreading jet. The energy injection avoids these problems, but requires is an element of(e) > 1 (k = 2), spherical outflow, and is an element of(B) < 10(-9). Conclusions. In light of the extreme microphysical parameters required by the energy-injection model, we favour a jet-break scenario where nu(m) < nu(sa) to explain the observations. This scenario gives physically meaningful microphysical parameters, and it also naturally explains the reported detection of linear and circular polarisation.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

BN - Astronomy and celestial mechanics, astrophysics

OECD FORD branch

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Project

<a href="/en/project/7AMB14DE001" target="_blank" >7AMB14DE001: Comparing synthetic lightcurves of GRB afterglows with observational data from GROND.</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

1432-0746

e-ISSN

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Volume of the periodical

2016

Issue of the periodical within the volume

589

Country of publishing house

FR - FRANCE

Number of pages

12

Pages from-to

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UT code for WoS article

000375318300049

EID of the result in the Scopus database

2-s2.0-84964577720