2012/03/31 by R. Margutti, E. Zaninoni, M. G. Bernardini +24 · 166 citations
Physics and Astronomy · #Afterglow #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Light curve #Optics #Physics #Pulsars and Gravitational Waves Research #Rest frame #Swift #X-ray #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1093/mnras/sts066
published in Monthly Notices of the Royal Astronomical Society 428(1), 729-742 (Oxford University Press) · MNRAS Accepted. 15 pages. On-line tables available
arxiv created 2012/10/11 · openalex publication_date 2012/10/25 · arxiv updated 2015/06/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present a comprehensive statistical analysis of Swift X-ray light curves of gamma-ray bursts (GRBs) collecting data from more than 650 GRBs discovered by Swift and other facilities. The unprecedented sample size allows us to constrain the rest-frame X-ray properties of GRBs from a statistical perspective, with particular reference to intrinsic time-scales and the energetics of the different light-curve phases in a common rest-frame 0.3-30 keV energy band. Temporal variability episodes are also studied and their properties constrained. Two fundamental questions drive this effort: (i) Does the X-ray emission retain any kind of `memory' of the prompt γ-ray phase? (ii) Where is the dividing line between long and short GRB X-ray properties? We show that short GRBs decay faster, are less luminous and less energetic than long GRBs in the X-rays, but are interestingly characterized by similar intrinsic absorption. We furthermore reveal the existence of a number of statistically significant relations that link the X-ray to prompt γ-ray parameters in long GRBs; short GRBs are outliers of the majority of these two-parameter relations. However and more importantly, we report on the existence of a universal three-parameter scaling that links the X-ray and the γ-ray energy to the prompt spectral peak energy of both long and short GRBs: EX,iso propto Egamma,iso1.00 ± 0.06 / Epk0.60 ± 0.10.