Ten years of Swift: A universal scaling for short and long gamma-ray bursts (EX,iso - Eγ,iso - Epk)

Abstract

From the comprehensive statistical analysis of Swift X-ray light-curves collected from the launch of the Swift satellite until the end of 2010, we found a three-parameter correlation between the isotropic energy emitted in the rest frame 1-10<SUP>4</SUP> keV energy band during the prompt emission (E<SUB>γ,iso</SUB>), the rest frame peak of the prompt emission energy spectrum (E<SUB>pk</SUB>), and the X-ray energy emitted in the rest frame 0.3-30 keV observed energy band (E<SUB>X,iso</SUB>), computed excluding the contribution of the flares. The importance of this scaling law is that it is followed by both long and short GRBs, and, at the same time, involves prompt and afterglow emission quantities. Therefore there are some properties which are shared by long and short GRBs as a whole. We updated this correlation considering all GRBs observed until June 2014, confirming the existence of this scaling law, and examining some particular GRBs, as 090426 and 100816A. We also discuss the physics that is driving this correlation.