Wandering Supermassive Black Hole Detected in Distant Spiral Galaxy

Using the Arecibo and Gemini observatories, astronomers have detected a mobile supermassive black hole in a galaxy called SDSS J043703.67+245606.8 (hereafter J0437+2456). J0437+2456 is a Sb-type spiral galaxy located approximately 230 million light-years away in the constellation of Taurus. First…

Using the Arecibo and Gemini observatories, astronomers have detected a mobile supermassive black hole in a galaxy called SDSS J043703.67+245606.8 (hereafter J0437+2456).

J0437+2456 is a Sb-type spiral galaxy located approximately 230 million light-years away in the constellation of Taurus.

First detected in 2018, the galaxy’s supermassive black hole has a mass of about three million times that of the Sun.

“We don’t expect the majority of supermassive black holes to be moving; they’re usually content to just sit around,” said Dr. Dominic Pesce, an astronomer at the Harvard & Smithsonian Center for Astrophysics.

“They’re just so heavy that it’s tough to get them going. Consider how much more difficult it is to kick a bowling ball into motion than it is to kick a soccer ball — realizing that in this case, the ‘bowling ball’ is several million times the mass of our Sun. That’s going to require a pretty mighty kick.”

Using observations with the Arecibo and Gemini Observatories, Dr. Pesce and colleagues confirmed the initial detection.

They found that J0437+2456’s supermassive black hole is moving with a speed of about 177,000 kmh (110,000 mph). But what’s causing the motion is not known.

“We may be observing the aftermath of two supermassive black holes merging,” said Dr. Jim Condon, a radio astronomer at the National Radio Astronomy Observatory.

“The result of such a merger can cause the newborn black hole to recoil, and we may be watching it in the act of recoiling or as it settles down again.”

But there’s another, perhaps even more exciting possibility: the black hole may be part of a binary system.

“Despite every expectation that they really ought to be out there in some abundance, scientists have had a hard time identifying clear examples of binary supermassive black holes,” Dr. Pesce said.

“What we could be seeing in J0437+2456 is one of the black holes in such a pair, with the other remaining hidden to our radio observations because of its lack of maser emission.”

The team’s paper was published in the Astrophysical Journal.

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Dominic W. Pesce et al. 2021. A Restless Supermassive Black Hole in the Galaxy J0437+2456. ApJ 909, 141; doi: 10.3847/1538-4357/abde3d