Source: Chandra CXC
RCW86 supernova remnant.
Image credits: NASA/JPL-Caltech/B. Williams (NCSU)
Chandra, XMM-Newton, Spitzer, and WISE - combined to make a new discovery on a very old supernova remnant, in a location where Chinese astronomers witnessed an event in 185 AD, documenting a mysterious "guest star" that remained for 8 months. The data now revealed shows it was a Type Ia Supernova. (see source)