The 80 Ms follow-up of the X-ray afterglow of GRB 130427A challenges the standard forward shock model

DOI: 
10.1093/mnras/stw1704
Publication date: 
01/10/2016
Main author: 
De Pasquale, M.
IAA authors: 
Oates, S. R.
Authors: 
De Pasquale, M.;Page, M. J.;Kann, D. A.;Oates, S. R.;Schulze, S.;Zhang, B.;Cano, Z.;Gendre, B.;Malesani, D.;Rossi, A.;Troja, E.;Piro, L.;Boër, M.;Stratta, G.;Gehrels, N.
Journal: 
Monthly Notices of the Royal Astronomical Society
Refereed: 
Yes
Publication type: 
Article
Volume: 
462
Pages: 
1111-1122
Abstract: 
GRB 130427A was the brightest gamma-ray burst detected in the last 30 yr. With an equivalent isotropic energy output of 8.5 × 10<SUP>53</SUP> erg and redshift z = 0.34, it uniquely combined very high energetics with a relative proximity to Earth. As a consequence, its X-ray afterglow has been detected by sensitive X-ray observatories such as XMM-Newton and Chandra for a record-breaking baseline longer than 80 million seconds. We present the X-ray light curve of this event over such an interval. The light curve shows a simple power-law decay with a slope α = 1.309 ± 0.007 over more than three decades in time (47 ks-83 Ms). We discuss the consequences of this result for a few models proposed so far to interpret GRB 130427A, and more in general the significance of this outcome in the context of the standard forward shock model. We find that this model has difficulty in explaining our data, in both cases of constant density and stellar-wind circumburst media, and requires far-fetched values for the physical parameters involved.
Database: 
ADS
SCOPUS
WOK
URL: 
https://ui.adsabs.harvard.edu/#abs/2016MNRAS.462.1111D/abstract
ADS Bibcode: 
2016MNRAS.462.1111D
Keywords: 
gamma-ray burst: general;gamma-ray burst: individual: GRB 130427A;Astrophysics - High Energy Astrophysical Phenomena