Spatially Resolved X-Ray Spectroscopy of Vela Shrapnel A

We present detailed X-ray spectroscopy of Vela shrapnel A with the XMM-Newton satellite. Vela shrapnel A is one of several protrusions identified as bullets from the Vela supernova explosion. The XMM-Newton image shows that shrapnel A consists of a bright knot and a faint trailing wake. We extracted spectra from various regions, finding a prominent Si Lyα emission line in all the spectra. All the spectra are well represented by the nonequilibrium ionization (NEI) model. The abundances are estimated to be O~0.3, Ne~0.9, Mg~0.8, Si~3, and Fe~0.8 times their solar values. The nonsolar abundance ratio between O and Si indicates that shrapnel A originates from a deep layer of a progenitor star. We found that the relative abundances between heavy elements are almost uniform in shrapnel A, which suggests that the ejecta from the supernova explosion are well mixed with swept-up interstellar medium.