This image depicts the X-ray emission from dwarf galaxy J1329+3234 (center in this image), and from a background AGN (lower right), measured by XMM-Newton in June 2013.
Located over 200 million light-years away, the dwarf galaxy contains a few hundred million stars and is similar in size to the Small Magellanic Cloud, one of our nearest neighboring galaxies.
Astronomers were intrigued to discover infrared signatures of an accreting black hole when they studied this galaxy with NASA's WISE spacecraft in 2013. When they subsequently observed the galaxy with ESA's XMM-Newton X-ray observatory they were surprised to detect X-ray emission over 100 times stronger than expected for this galaxy.
The combined X-ray and infrared properties of this galaxy can only be explained by the presence of a massive black hole residing in J1329+3234, similar to the super-massive black holes found at the centers of much more massive galaxies.
The image is constructed from 2-10 keV X-ray emission and has been smoothed. The color code represents the intensity of X-ray emission with blue being more intense and red less intense. The white bar indicates a width of 10 arcseconds, equivalent to 3.3 kpc at the distance of this galaxy. North is up, east to the left.
Image credit: ESA/XMM-Newton/N. Secrest, et al. (2015)
Note: For more information, see XMM-Newton Spots Monster Black Hole Hidden in Tiny Galaxy.