We present a deep observation with the X-ray Multi-Mirror Mission of PSR B1823–13 , a young pulsar with similar properties to the Vela pulsar .
We detect two components to the X-ray emission associated with PSR B1823–13 : an elongated core of extent 30 ^ { \prime \prime } immediately surrounding the pulsar , embedded in a fainter , diffuse component of emission 5 ^ { \prime } in extent , seen only on the southern side of the pulsar .
The pulsar itself is not detected , either as a point source or through its pulsations .
Both components of the X-ray emission are well fit by a power law spectrum , with photon index \Gamma \approx 1.6 and X-ray luminosity ( 0.5–10 keV ) L _ { X } \approx 9 \times 10 ^ { 32 } erg s ^ { -1 } for the core , and \Gamma \approx 2.3 and L _ { X } \approx 3 \times 10 ^ { 33 } erg s ^ { -1 } for the diffuse emission , for a distance of 4 kpc .
We interpret both components of emission as corresponding to a pulsar wind nebula , which we designate G18.0–0.7 .
We argue that the core region represents the wind termination shock of this nebula , while the diffuse component indicates the shocked downstream wind .
We propose that the asymmetric morphology of the diffuse emission with respect to the pulsar is the result of a reverse shock from an associated supernova remnant , which has compressed and distorted the pulsar-powered nebula .
Such an interaction might be typical for pulsars at this stage in their evolution .
The associated supernova remnant is not detected directly , most likely being too faint to be seen in existing X-ray and radio observations .