## GRB 130427A afterglow: A test for GRB models

12th Multifrequency Behaviour of High Energy Cosmic Sources Workshop, MULTIF 2017, Palermo, Italy, 12 - 17 June 2017, vol.306, pp.1-8

• Publication Type: Conference Paper / Full Text
• Volume: 306
• Doi Number: 10.22323/1.306.0071
• City: Palermo
• Country: Italy
• Page Numbers: pp.1-8

#### Abstract

Gamma-ray Burst 130427A had the largest fluence for almost 30 years. With an isotropic energy output of and redshift of 0.34, it combined a very high energy release with a relative proximity to Earth in an unprecedented fashion.

Sensitive X-ray facilities such as {\it XMM-Newton} and {\it Chandra} detected the afterglow of this event for a record-breaking baseline of 90 Ms. We show the X-ray light curve of GRB 130427A of this event over such an interval. The light curve shows an unbroken power law decay with a slope of  over more than three decades in time.

In this presentation, we investigate the consequences of this result for the scenarios proposed to interpret GRB 130427A and the implications in the context of the forward shock model (jet opening angle, energetics, surrounding medium). We also remark the chance of extending GRB afterglow observations for several hundreds of Ms with {\it Athena}.