Narrow band UV imaging and soft x-ray spectral studies of Vela-D with Astrosat.

We present NUV, FUV and soft x-ray (0.3-10 keV) imaging and x-ray spectroscopic studies of two, 30' diameter, adjacent, segments of the x-ray, uv- and optically bright, Vela-D "bullet" of the Vela supernova remnant (SNR), using the Astrosat/UVIT (with F169M, F172M filters) and Astrosat/SXT instruments. The x-ray bright protuberances from the shell-like, 11000 yr old, nebula show unusual morphology, and have been interpreted as either fast moving ejecta from an asymmetric supernova explosion, or the outcome of a supernova shock moving in to a less dense medium. Combined with archival data from earlier FUV and soft x-ray missions, our observations trace the nebular emission (mainly) from CIV (1550 A) and HeII (1640 A), thus bridging gap between the x-ray bright ($10^{6-7}$ K) and the cool, optical regions. By mapping the locally evolving physical conditions, we study the shock-CSM/ISM interaction, and better constrain the origins and physical nature of this segment of the Vela Supernova Remnant.