UT’s telescope finds massive black hole, challenges former theories


Image of lenticular galaxy NGC 1277 taken with Hubble Space Telescope. This small, flattened galaxy contains one of the most massive central black holes ever found. At 17 billion solar masses, the black hole weighs an extraordinary 14% of the total galaxy mass. (Credit: NASA/ESA/Andrew C. Fabian)

Bobby Blanchard

Theories about how black holes are grown inside a galaxy may have to be modified because of a recent discovery astronomers made using UT’s Hobby-Eberly Telescope.

While working on a study to better understand how galaxies grow and form together, astronomers discovered a massive black hole with a size relative to its galaxy bigger than any before. Discovered in galaxy NGC 1277, the black hole makes up 14 percent of the galaxy’s mass. Usually, black holes make up .1 percent of  a galaxy’s mass. This black hole has the mass of 17 billion suns.

This diagram shows how the diameter of the 17-billion-solar-mass black hole in the heart of galaxy NGC 1277 compares with the orbit of Neptune around the Sun. The black hole is eleven times wider than Neptune's orbit. Shown here in two dimensions, the "edge" of the black hole is actually a sphere. This boundary is called the "event horizon," the point from beyond which, once crossed, neither matter nor light can return. (Credit: D. Benningfield/K. Gebhardt/StarDate)

Karl Gebhardt, UT professor and member of the study, said the black hole “stuck out like a sore thumb.”

“It just has such an extreme black hole mass compared to its galaxy, that it is really going to strain the theories as to how you grow a black hole inside a galaxy,” Gebhardt said.

The study is ongoing, but Gebhardt said if they find other galaxies in similar situations then this could contradict current black hole theories.

“If this is an extreme oddball galaxy, then, you know, odd things happen, this is a big universe, you’re going to get some weird ones now and then,” Gebhardt said. “But if we find these to be a pattern, which is my suspicion now, then we are going to have to modify the theories for how you grow a black hole.” 

NGC 1277 (center) is embedded in the nearby Perseus galaxy cluster. All the elliptical and round yellow galaxies in the picture are located in this cluster. NGC 1277 is a relatively compact galaxy compared to the galaxies around it. The Perseus cluster is 250 million light years from us. (Credit: David W. Hogg, Michael Blanton, and the SDSS Collaboration)