The X-ray emission of the supernova remnant W49B observed with XMM-Newton

Abstract

We report on an XMM-Newton EPIC observation of the galactic supernova remnant W49B Its morphology exhibits an X-ray bright barrel-shaped nebula terminated on its eastern end by an elongated structure perpendicular to the barrel axis and aligned with the radio shell The X-ray spectrum of W49B is characterized by strong K emission lines from Si S Ar Ca and Fe While we found an East West anisotropy in the abundances there is no clear evidence for radial stratification of the elements A high overabundance of Ni is required in the bright central barrel and we clearly confirm the detection of Cr and Mn line emission Our results support a scenario where X-ray emission comes from the ejecta interacting with a dense belt of ambient material but it is also possible that it is the result of an asymmetric bipolar explosion where the eastern jet is hotter and Fe-richer than the western one The observed abundances are compared with the yields produced in hypernovae and supernovae nucleosynthesis models Although possible the claim for an association of W49B with a gamma-ray burst is not directly supported by the abundance pattern