We see these galaxies as they existed billions of years ago. The amount of matter connected with quasars and galaxies at such distances and distant times in the past is probably not be the same as we would measure in the local universe today, so it's very important to find out how much mass we are actually looking at in the supercluster. The first step is to look for signs of extra galaxies in the area, and now we have evidence for a surplus of galaxies. This research was presented Monday during the winter meeting of the American Astronomical Society in San Diego, California. The same research is also being prepared for submission to the Astrophysical Journal.
Quasars are galaxies with bright cores, most likely powered by giant black holes.
Some quasars are as bright as a trillion suns. This particular large quasar group holds a total of 18 quasars in a space roughly a half billion light years across. Usually, only two to three quasars would be expected in a region this size if there were no galaxy cluster present. The quasars are not the only discovery made. They are thought to originate in the haloes surrounding galaxies, which are probably too faint and can't be seen directly.