Spatially Resolved X‐Ray Spectroscopy of Vela Shrapnel A

We present the detailed X-ray spectroscopy of Vela shrapnel A with theXMM-Newton satellite. Vela shrapnel A is one of several protrusions identifiedas bullets from Vela supernova explosion. The XMM-Newton image shows thatshrapnel A consists of a bright knot and a faint trailing wake. We extractedspectra from various regions, finding a prominent Si Ly$_\alpha$ emission linein all the spectra. All the spectra are well represented by the non-equilibriumionization (NEI) model. The abundances are estimated to be O$\sim$0.3,Ne$\sim$0.9, Mg$\sim$0.8, Si$\sim$3, Fe$\sim$0.8 times their solar values. Thenon-solar abundance ratio between O and Si indicates that shrapnel A originatesfrom a deep layer of a progenitor star. We found that the relative abundancesbetween heavy elements are almost uniform in shrapnel A, which suggests thatthe ejecta from supernova explosion are well mixed with swept-up interstellarmedium.Comment: 11 pages, 10 figures, ApJ 10 May 2006, v642 2 issu