NASA has discovered 26 black holes in the Andromeda Galaxy, the nearest galaxy to our own Milky Way.
The discovery, which is the largest to date, was made using 150 observations over a 13-year period from the Chandra X-ray observatory, with additional support from the European Space Agency’s XMM-Newton X-ray observatory.
The black holes, which are technically “candidates” until further confirmation, belong to the stellar mass category, which means they formed from the deaths of huge stars up to 10 times the size of the Sun. They were detected because they are sucking in material from nearby stars.
“While we are excited to find so many black holes in Andromeda, we think it’s just the tip of the iceberg,” said Robin Barnard of Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts and lead author of the report. “Most black holes won’t have close companions and will be invisible to us.”
The Andromeda Galaxy is widely believed to be a sister galaxy to the Milky way. NASA said it expects the two galaxies to collide several billion years in the future.
The findings will be published in the 20 June issue of The Astrophysical Journal.