Dust scattering X-ray expanding rings around gamma-ray bursts

Abstract

Scattering by dust grains in our Galaxy can produce X-ray halos, visible as expanding rings, around GRBs. This has been observed in three GRBs to date, allowing to derive accurate distances for the dust clouds as well as some constraints on the prompt GRB X-ray emission that was not directly observed. We developed a new analysis method to study dust scattering expanding rings and have applied it to all the XMM-Newton and Swift/XRT follow-up observations of GRBs.

Proceedings of the international conference Swift and GRBs: Unveiling the Relativistic Universe - Venice, 5-9 June 2006 - To appear in "Il Nuovo Cimento"