Theneighboring Andromeda galaxyhasa black hole that sometimes emits more luminosity than would be expected for its mass. Why? An international team of scientists is in charge of solving this astronomical mystery, including researchers from the Institute of Space Sciences of the CSIC.
As published by scientists in the magazineNature, exist fmathematical formulas that establish what the maximum luminosity of a cosmic object should be based on its mass– known as the “Eddington luminosity” -. Above this limit, for example, a normal star would decay. For a black hole with a mass ten times that of the Sun, this figure is 1×1032 watts, a million times greater than the luminosity of the Sun. However, the Andromeda black hole sometimes exceeds this limit.
This has led to identify it as aultra-luminous X-ray source (ULXfor its acronym in English). These are usually intense X-ray emissions frombinary systems consisting of a star and a black holethat mutually orbit each other at high speed, and are a consequence of the high temperatures reached by the gas from the star when it falls towards the black hole. Before being swallowed, this matter creates an accretion disk around the black hole and emits intense X-rays. The luminosity of this phenomenondepends on the mass of the black holeSince the more massive it is, the more powerful its gravitational field will be and the more matter it will be able to absorb, which will give it greater luminosity. In other words,the ultraluminosity of the hole in Andromeda is due to the huge banquet of starsthat devours.
The results obtained by this research open a new window of understanding of black holes and their evolution in the universe.
