Vela X is a pulsar wind nebula ( PWN ) associated with the active pulsar B0833-45 and contained within the Vela supernova remnant ( SNR ) .
A collimated X-ray filament ( “ cocoon ” ) extends south-southwest from the pulsar to the center of Vela X. VLA observations uncovered radio emission coincident with the eastern edge of the cocoon and H.E.S.S .
has detected TeV \gamma -ray emission from this region as well .
Using XMM- Newton archival data , covering the southern portion of this feature , we analyze the X-ray properties of the cocoon .
The X-ray data are best fit by an absorbed nonequilibrium plasma model with a powerlaw component .
Our analysis of the thermal emission shows enhanced abundances of O , Ne , and Mg within the cocoon , indicating the presence of ejecta-rich material from the propagation of the SNR reverse shock , consistent with Vela X being a disrupted PWN .
We investigate the physical processes that excite the electrons in the PWN to emit in the radio , X-ray and \gamma -ray bands .
The radio and non-thermal X-ray emission can be explained by synchrotron emission .
We model the \gamma -ray emission by Inverse Compton scattering of electrons off of cosmic microwave background ( CMB ) photons .
We use a 3-component broken power law to model the synchrotron emission , finding an intrinsic break in the electron spectrum at \sim 5 \times 10 ^ { 6 } keV and a cooling break at \sim 5.5 \times 10 ^ { 10 } keV .
This cooling break along with a magnetic field strength of 5 \times 10 ^ { -6 } G indicate that the synchrotron break occurs at \sim 1 keV .