Now, turn to the problem of the biggest, most luminous galaxies in the local Universe: the brightest cluster galaxies that sit at the center of galaxy clusters. These objects likely grew huge through mergers and absorption of smaller galaxies, until they eventually became the gravitational focus of their clusters. As befits their heft, they also contain the biggest supermassive black holes we’ve identified.
However, the new study shows there is a mismatch between the mass estimates from the MBH-σrelation and those generated by FP analysis. Prior estimates were based on the MBH-σ relation alone, in the absence of kinematic modeling. The authors of the new paper used X-ray and radio emissions for 18 bright cluster galaxies, and placed their black holes on the fundamental plane. This revealed that their masses could be as much as 10 times greater than estimates based on the MBH-σ relation, meaning the largest black holes have masses tens of billions of times greater than the Sun.