The composite form of the supernova remnant 3C 400.2: Two interacting supernova remnants or a single supernova remnant with a blow-out?

Abstract

3C 400.2 is a galactic supernova remnant with a complex morphology consisting of two overlapping shells of different diameters: a large shell to the southeastern side and a small shell to the northwestern side. In order to decide whether this morphology is due to two supernova explosions or to the blow-out of one supernova explosion in a medium with a density gradient, we study the kinematics of both shells. Hα Fabry-Perot data are more in agreement with the scenario of only one supernova explosion undergoing a blow-out due to a density gradient in clumpy media.