Chandra’s contribution to the image shows the energy intensity of the X-rays. The lowest energy X-rays are colored red, such as those in the cooler inner material which is surrounded by higher energy blue blast wave. Orange shows the highest energy X-rays. Hubble added optical details in red, green and blue including all the stars in the image. The separate contributions can be seen below, Chandra on the left and Hubble on the right.

Cool ...