On the origin of the jet-like radio/X-ray morphology of G290.1-0.8

Abstract

Context. The origin and evolution of supernova remnants of the mixed-morphology class is not well understood. Several remnants present distorted radio or X-ray shells with jet-like structures. G290.1-0.8 (MSH 11-61A) belongs to this particular class. Aims. We aim to investigate the nature of this supernova remnant in order to unveil the origin of its particular morphology. We based our work on the study of the X-ray emitting plasma properties and the conditions imposed by the cold interstellar medium where the remnant expanded. Methods. We use archival radio, HI line data and X-ray observations from XMM-Newton and Chandra observatories, to study G290.1-0.8 and its surrounding medium in detail. Spatially resolved spectral analysis and mean photon energy maps are used to obtain physical and geometrical parameters of the source. Radio continuum and HI line maps give crucial information to understand the radio/X-ray morphology. Results. The X-ray images show that the supernova remnant presents two opposite symmetric bright spots on a symmetry axis running towards the north west-south east direction. Spectral analysis and mean photon energy maps confirm that the physical conditions of the emitting plasma are not homogeneous throughout the remnant. In fact, both bright spots have higher temperatures than the rest of the plasma and its constituents have not reached ionization equilibrium yet. HI line data reveal low density tube-like structures aligned along the same direction. This evidence supports the idea that the particular X-ray morphology observed is a direct consequence of the structure of the interstellar medium where the remnant evolved. However, the possibility that an undetected point-like object, as a neutron star, exists within the remnant and contributes to the X-ray emission cannot be discarded. Finally, we suggest that a supernova explosion due to the collapse of a high-mass star with a strong bipolar wind can explain the supernova remnant morphology.