The X-ray structure of the pulsar bow shock G189.22+2.90 in the supernova remnant IC 443

B. M. Gaensler, S. Chatterjee, P. O. Slane, E. Van Der Swaluw, F. Camilo, John Hughes

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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 postshock 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, M ≲ 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 standoff distance between the star and the head of the bow shock, which allows us to estimate a space velocity for the neutron star of ∼230 km s-1, independent of distance. We detect thermal emission from the neutron star surface at a temperature of 102 ± 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 1-2 north and south of the neutron star.

Original languageEnglish (US)
Pages (from-to)1037-1042
Number of pages6
JournalAstrophysical Journal
Issue number2 I
StatePublished - Sep 10 2006


All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Stars: neutron
  • Stars: winds, outflows

Cite this

Gaensler, B. M., Chatterjee, S., Slane, P. O., Van Der Swaluw, E., Camilo, F., & Hughes, J. (2006). The X-ray structure of the pulsar bow shock G189.22+2.90 in the supernova remnant IC 443. Astrophysical Journal, 648(2 I), 1037-1042.