Ejecta and Reverse Shock Movies of the Galactic Supernova Remnant Cassiopeia A

Associated with the paper "Cassiopeia A's Reverse Shock and its Effects on the Expanding SN Ejecta' by R.A. Fesen et al. (2025), a series of short animations were made to help to clarify the proper motions of the reverse shock through the appearance of new optical emission knots and filaments as detected in images spanning several years. Most make use of Hubble Space Telescope images taken between January 2000 and June 2008. Video animations for several specific regions around the Cas A remnant were made. The user should reference the Fesen et al. (2025) paper for information as to the region names for the various locations studied around the remnant. The titles of the animation files are meant to be self-explanatory as to what regions are being shown and whether the file shows proper motions in the reference frame of the sky or the outwardly expanding ejecta. In all cases, the observed motions are repeated (looped) either 5 to 7 times to make the motions easier to observe. Each animation begins with a descriptive frame. All movies are in a MPEG-4 container, specifically encoded with the H264 codec. List of animation files: NW-ejecta-reference-frame.mp4 NW-sky-reference-frame.mp4 P1-sky-reference-frame.mp4 P2nP3-ejecta-reference-frame.mp4 P2nP3-sky-reference-frame.mp4 P5nP6-ejecta-reference-frame.mp4 P13-ejecta-reference-frame.mp4 P14-ejecta-reference-frame.mp4 P15-ejecta-reference-frame.mp4