  Deep Chandra ACIS observations of the region around the putative pulsar, CXOU
J061705.3+222127, in the supernova remnant IC443 reveal an
~5$^{\prime\prime}$-radius ring-like structure surrounding the pulsar and a
jet-like feature oriented roughly north-south across the ring and through the
pulsar's location at 06$^{\rm h}$17$^{\rm m}$5.200$^{\rm s}$
+22$^{\circ}$21$^{\prime}$27.52$^{\prime\prime}$ (J2000.0 coordinates). The
observations further confirm that (1) the spectrum and flux of the central
object are consistent with a rotation-powered pulsar, (2) the non-thermal
spectrum and morphology of the surrounding nebula are consistent with a pulsar
wind and, (3) the spectrum at greater distances is consistent with thermal
emission from the supernova remnant. The cometary shape of the nebula,
suggesting motion towards the southwest, appears to be subsonic: There is no
evidence either spectrally or morphologically for a bow shock or contact
discontinuity; the nearly circular ring is not distorted by motion through the
ambient medium; and the shape near the apex of the nebula is narrow. Comparing
this observation with previous observations of the same target, we set a 99%
confidence upper limit to the proper motion of CXOU J061705.3+222127 to be less
than 44 mas/yr (310 km/s for a distance of 1.5 kpc), with the best-fit (but not
statistically significant) projected direction toward the west.

High Energy Astrophysical Phenomena