The heaviest black hole collision ever observed, produced by the gravitational-wave GW190521, might actually be something even more mysterious. An international team of scientists led by the Galician Institute of High Energy Physics (IGFAE) and the University of Aveiro shows that the heaviest black hole collision ever observed might be the merger of two boson stars, that might be made up of elusive candidates for dark matter. According to the scientists, this would be the first evidence of the existence of these hypothetical objects which constitute 27 per cent of the universe.
Heaviest black hole collision
According to the study, gravitational waves are ripples in the fabric of spacetime that travel at the speed of light. These waves originate in the most violent events of the universe that carries information about their sources. With the help of LIGO detectors (Livingston and Hanford, USA) and Virgo (Cascina, Italy) humans can detect and interpret gravitational waves. The detection till now has observed around 50 gravitational wave signals. These waves have originated in the merger of two of the most mysterious entities in the Universe, black holes and neutron stars, according to the study.
Since September 2020, the LIGO and Virgo announced to the world the gravitational-wave signal GW190521. According to their analysis, the signal was consistent with the collision of two heavy black holes, of 85 and 66 times the mass of the sun, which produced a final black hole with 142 solar masses. According to the study, the black hole was detected for the first time and this discovery would help in finding two black hole families, the stellar-mass black holes that form from the collapse of stars. It would also help in finding about supermassive black holes that hide in the centre of almost every galaxy, including the Milky Way.
The team has also compared the GW190521 signal to computer simulations of boson-star mergers. Dr. Calderón Bustillo said that detection made by LIGO and Virgo leads to a larger mass for the final black hole of about 250 solar masses. She added that the formation of an intermediate-mass black hole remains true. Boson stars are objects almost as compact as black holes but they do not have a no-return surface like them. Professor Jose A. Font from the University of Valencia said that analysis favours the merging black-holes hypothesis. He added that a boson star merger is preferred by the data.