We present a deep observation with the Chandra X-ray Observatory of the neutron star bow shock G189.22+2.90 in the supernova remnant ( SNR ) IC 443 .
Our data confirm the cometary morphology and central point source seen previously , but also reveal considerable new structure .
Specifically , we find that the X-ray nebula consists of two distinct components : a “ tongue ” of bright emission close to the neutron star , enveloped by a larger , fainter “ tail ” .
We interpret the tongue and tail as delineating the termination shock and the post-shock flow , respectively , as previously identified also in the pulsar bow shock G359.23–0.82 ( “ the Mouse ” ) .
However , for G189.22+2.90 the tongue is much less elongated than for the Mouse , while the tail is much broader .
These differences are consistent with the low Mach number , \mathcal { M } \lesssim 2 , expected for a neutron star moving through the hot gas in a SNR ’ s interior , supporting the case for a physical association between G189.22+2.90 and IC 443 .
We resolve the stand-off distance between the star and the head of the bow shock , which allows us to estimate a space velocity for the neutron star of \sim 230 km s ^ { -1 } , independent of distance .
We detect thermal emission from the neutron star surface at a temperature of 102 \pm 22 eV , which is consistent with the age of SNR IC 443 for standard neutron star cooling models .
We also identify two compact knots of hard emission located 1 ^ { \prime \prime } -2 ^ { \prime \prime } north and south of the neutron star .