ESO 444-46
ESO 444-46 is a class E4 supergiant elliptical galaxy; the dominant and brightest member of the Abell 3558 galaxy cluster around away in the constellation Centaurus. It lies within the core of the massive Shapley Supercluster, one of the closest neighboring superclusters. It is one of the largest galaxies in the local universe, and possibly contains one of the most massive black holes known. The black hole's mass is very uncertain, with estimates ranging from as low as, to as high as.
Physical characteristics
Globular clusters
ESO 444-46 has an estimated population of about 27,000 globular clusters which may be one of the largest populations ever studied. This is in contrast to 15,000 globular clusters in Messier 87, and 200 in the Milky Way. However, this large number may be due to the addition of Intracluster globular clusters since the galaxy lies about 1 arcmin of the center of Abell 3558.Supermassive black hole
A calculation using the spheroidal luminosity method by estimating the stellar density of the central region using its brightness, yielded a mass of 77.6 billion solar masses. This would make it one of the most massive black holes known – nearly twelve times the mass of the black hole in Messier 87, and 18,000 times more massive than Sagittarius A*, the Milky Way's central black hole. A black hole of this mass has a Schwarzschild radius of 1,530 AU.Alternative calculations using the M-sigma relation and the newer core break radius method yielded estimates of and, respectively.