VLA OBSERVATIONS OF THE SUPERNOVA REMNANT 3C400.2 AT 327 MHZ AND 1465MHZ

We have observed the supernova remnant 3C400.2 with the VLA at 327.5 a nd 1465 MHz. The images, obtained with an angular resolution better th an 1' and a sensitivity of 1 mJy/beam, show significant new features t hat suggest that the radio remnant may be formed by two highly symmetr ical circular shells that overlap in the northwest. The x-ray emitting region fills the interior of the radio shells, peaking in the region where the radio continuum synchrotron rings overlap. A detailed spatia l correlation of optical filaments with the newly discovered radio fea tures is found. Two different scenarios consistent with the observed m orphologies are proposed: (a) 3C400.2 is the result of an explosion oc curring inside the wind-driven bubble excavated by a massive progenito r star, or (b) the distribution of the emission observed in the differ ent spectral ranges is the signature of two different SN explosions.