Explanation:
Violent
galaxy mergers can feed supermassive
black holes.
Theoretically, the result is intense emission from regions
near the supermassive black holes, creating the some of the
most luminous objects in the universe.
Astronomers dub these
Active Galactic Nuclei, or just AGN.
But for decades only about 1 percent of AGN seemed to be associated
with galaxy mergers.
New results from a premier sky survey
by NASA's Swift satellite
at hard (energetic) X-ray energies now
solidly show a strong association of AGN with
merging galaxies, though.
The hard X-rays more readily penetrate dust and gas clouds in
merging galaxies and reveal the presence of emission from
the active black holes.
In fact, these panels show the location (circled) of Swift
X-ray detected
supermassive black holes in a variety of
merging galaxy systems.
The optical images are from the Kitt Peak National Observatory in
Arizona.
At top center is NGC 7319 and the compact galaxy group
known as Stephan's Quintet.
