Chandra X-ray Observatory image of the supernova remnant Cassiopeia A (Cas
A). The red, green, and blue regions in this X-ray image of Cas A show where the intensity of low, medium, and high-energy X-rays, respectively, is greatest. While this photo shows the remains of the exploded star, light echoes show us reflected light from the explosion itself.
Credit: NASA/CXC/MIT/UMass Amherst/M.D.Stage et al. Low Resolution Image (jpg)
Three light echoes from the Cas A supernova are shown here in three rows. For each row, the left panel is a reference image while the middle panel shows the same field of view at a later time. Right panels show the difference between the two previous shots, highlighting the (changing) light echo. The position and size of the spectroscopy slit is indicated by the rectangular overlay. For all images, north is up and east is to the left. Credit: CfA/KPNO High Resolution Image (jpg) Low Resolution Image (jpg)