XMM-Newton image of X-ray light from the galaxy M100

This is an image of X-ray light from the galaxy M100. No longer do we see the prominent spiral arms of the galaxy, apparent in optical images. Instead, the X-ray image reveals high-energy activity throughout the galaxy. The most active region is the galaxy centre.

The red and orange regions are sources of very hot, diffuse gas
between stars. SN 1979C is the orange hotspot about 7 o'clock from the white galactic centre.

This XMM-Newton image is a composite of three X-ray energy bands: soft, 0.3-1.5 keV (in red); medium, 1.5-4 keV (in green); and hard, 4-10 keV (in blue, which is blended into the white core).