One of the smallest of the monstrous supermassive black holes observed so far has been discovered: with a mass equal to 200,000 times that of the Sun, it is buried by clouds of gas and dust at the center of the dwarf galaxy Mrk 462, located 110 million light years from we.
Identified thanks to NASA's Chandra X-ray observatory, it could help to better understand the growth of these mysterious cosmic objects, as researchers from Dartmouth College (United States) explained when presenting their study at the meeting of the American Astronomical Society.
The researchers used Chandra to study the X-ray emissions of eight dwarf galaxies in which an active supermassive black hole was suspected. Only for the galaxy Mrk 462 it was possible to ascertain the presence of a growing supermassive black hole, with a mass equal to 200,000 times that of the Sun. Surprisingly, the ratio between high-energy and low-energy X-rays suggested that the hole black was heavily darkened, 'buried' are thick clouds of dust.
"Since buried black holes are harder to spot than exposed ones, finding this specimen could mean there are far more dwarf galaxies out there with similar black holes," says astronomer Ryan Hickox.
"This is important because it could help us answer one of the most important questions in astrophysics: how do black holes get so large even in the earliest stages of the universe?"
The discovery suggests that some supermassive black holes are not born big and then get bigger again, but could grow from stellar masses up to 100 times the mass of the Sun.
