A comprehensive radio view of the extremely bright gamma-ray burst 130427A
Artikel i vetenskaplig tidskrift, 2014

GRB130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical of high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves at 1.4 and 4.8 GHz of GRB 130427A with the Westerbork Synthesis Radio Telescope (WSRT); and we obtained its most accurate position with the European Very Long Baseline Interferometry Network (EVN). Our flux density measurements are combined with all the data available at radio, optical and X-ray frequencies to perform broad-band modelling in the framework of a reverse-forward shock model and a two-component jet model, and we discuss the implications and limitations of both models. The low density inferred from the modelling implies that the GRB 130427A progenitor is either a very low metallicity Wolf-Rayet star, or a rapidly rotating, low-metallicity O star. We also find that the fraction of the energy in electrons is evolving over time, and that the fraction of electrons participating in a relativistic power-law energy distribution is less than 15 per cent. We observed intraday variability during the earliest WSRT observations, and the source sizes inferred from our modelling are consistent with this variability being due to interstellar scintillation effects. Finally, we present and discuss our limits on the linear and circular polarization, which are among the deepest limits of GRB radio polarization to date.

GRB 130427A

gamma-ray burst: individual: GRB 130427A


A. J. van der Horst

Universiteit Van Amsterdam

Z. Paragi

Joint Institute for VLBI in Europe

A. G. de Bruyn

University of Groningen, Kapteyn Astronomical Institute

Netherlands Foundation for Research in Astronomy

J. Granot

Open University of Israel

C. Kouveliotou

NASA Marshall Space Flight Center

K. Wiersema

University Of Leicester

R. L. C. Starling

University Of Leicester

P. A. Curran

Curtin University

Ramj Wijers

Universiteit Van Amsterdam

A. Rowlinson

Universiteit Van Amsterdam

G. A. Anderson

University of Southampton

University of Oxford

R. P. Fender

University of Oxford

University of Southampton

Jun Yang

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

R. G. Strom

Netherlands Foundation for Research in Astronomy

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 444 3151-3163


Astronomi, astrofysik och kosmologi