Potentially the most massive black hole ever discovered. At the least, it is one of the largest we know about, and is the largest in our region of space.
This black hole is sitting in the Holmberg 15A supergiant elliptical galaxy at the center of the Abell 85 galaxy cluster roughly 700 million light-years from us. That may sound like a vast distance, but relatively speaking to the overall size of the universe compared to the surface of the earth, it would be roughly the distance from New York City to Rochester New York.
It is potentially more than 15,000 (and up to 60,000) times larger than the Milkyway's supermassive black hole Sagittarius A, or double the size of the most massive object ever discovered in the universe (a quasar, TON 618, which is 66 billion masses of the sun). Scientists calculate the mass at 40 billion masses of the sun minimum, with a maximum size of 150 billion (https://en.wikipedia.org/wiki/Holmberg_15A) masses of the sun. The previous record-holder for the most massive black hole in our region is M87 (the one recently photographed) which has a mass of only 6.3 billion masses of the sun. Tat makes Holmberg 15A about 6.4 to 24 times more massive than M87. Sagittarius A, the ultramassive black hole in our own galaxy is 2.6 million solar masses, which makes Holmberg 15a's black hole about 15,000 to 58,000 times the size of our supermassive black hole
https://www.sciencealert.com/an-absolut ... llion-suns
