ESO 444-46 (Shapley 8-1, A3558-M1 or ESO 444-G 046) is a class E4 supergiant elliptical galaxy; the dominant and brightest member of the Abell 3558 galaxy cluster around 200.8 ± 14.1 megaparsecs (654.9 ± 45.99 million light-years) away in the constellation Centaurus. It lies within the core of the massive Shapley Supercluster (Shapley Concentration), 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 of 26.9 billion solar masses (M☉), (with estimates ranging from as low as 501 million M☉, to as high as 77.6 billion M☉) based on the break radius of the host galaxy.

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 (M87), 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 (Lsph) by estimating the stellar density of the central region using its brightness, yielded an initial mass of 77.6 +191.5−55.2 billion M☉ (1010.89 ± 0.54) (with the range being 22.4 billion M☉ to 269.1 billion M☉) (1010.35 to 1011.43). This would make it one of the most massive black holes known – nearly twelve times the mass of the black hole in Messier 87 (M87*), and 18,000 times more massive than Sagittarius A* (Sgr A*), the Milky Way's central black hole. A black hole of this mass has a Schwarzschild radius of 1,531 (with the range being 868.6 to 10,660) AU (about 458 billion km (with the range being 130 billion km to 1.59 trillion km) in diameter) or 102 (with the range being 28.8 to 354.8) times the distance between Neptune and the Sun.
Alternative calculations using the M-sigma relation (Mσ) and the newer core break radius method (Rb) yielded estimates of 501+787−306 million M☉ (108.70 ± 0.41) and 26.9+47.2−17.1 billion M☉ (1010.43 ± 0.44), respectively.

See also
List of galaxies
List of nearest galaxies
List of NGC objects (4001–5000)
List of spiral galaxies
NGC 4889
NGC 4874
IC 1101
ESO 383-76

Notes

References

External links
ESO 444-46 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images