HST/ACS imaging of a Balmer-dominated shock in Kepler's supernova remnant

Optical images of Kepler's supernova remnant obtained at two epochs, in 1987 at Las Campanas Observatory and in 2003 with the HST Advanced Camera for Surveys, show the motion of the Balmer-dominated forward shock. The measured proper motion, combined with estimates of the shock velocity, is used to derive a distance of 3.9-0.9+1.4 kpc to the remnant. The optical shock is clearly identified in the 0.2-0.65 keV band Chandra X-ray image of the remnant. However, there is no correlation between the optical filaments and features seen in 4-6 keV continuum dominated X-ray emission.