VRO 42.05.01 - A supernova remnant reenergizing an interstellar cavity

Abstract

Radio continuum observations are presented of the supernova remnant (SNR) VRO 42.05.01 (G166.0+4.3). An earlier model of this unusual SNR is elaborated. The model depicts the SNR breaking out from a warm medium of intermediate density, in which the supernova occurred, into a hot, tenuous interstellar cavity, presumably formed by one or more previous supernovae or stellar winds. This model is now shown to be quantitatively consistent with hydrodynamical calculations of an SNR breaking out of a cloud. The SNR has renergized a section of the hot cavity of extent about 120 pc. The interface between the warm medium and the hot cavity has been excited into emission around the breakthrough point. It is argued that the linear features, of width 1 pc and length about 80 pc, which are seen crossing the SNR, are regions of this interface where the line of sight is tangential to the surface.