X-ray, Radio, and Optical Observations of Cassiopeia A

We have performed a multi-wavelength comparison of Cassiopeia A using Very Large Array, Hubble Space Telescope, and Chandra X-ray Observatory images. By separating components spectrally, we find clear associations between the emission at the three wavebands. We separate the emitting material into two components -- shocked circumstellar medium (CSM) and shocked ejecta, which show the same respective morphologies and proper motions in the different bands. In the shocked CSM, we find matched low-energy enhanced X-ray emission and optical quasi-stationary flocculi, and X-ray continuum-dominated emission matched with filamentary radio structures. In the shocked ejecta, we find matched silicon and iron dominated X-ray emission and optical fast-moving knots.