Astronomers uncovered that a well-known X-ray binary, whose exact nature has been a mystery to scientists until now, is actually a hidden ultraluminous X-ray source.
Several international research groups have already confirmed the theory that there are two black holes at the centre of the distant galaxy OJ 287, first suggested by astronomers at the University of Turku, Finland. A new study shows that satellite observations conducted in 2021 revealed the smaller black hole of the pair for the first time.
Quasars are extremely luminous galaxies and their light is produced by a supermassive black hole at their center, which is actively feeding on the cosmic gas and dust around it. Previous theories have suggested that quasars and their supermassive black holes are formed when galaxies collide, but a recent doctoral thesis at the University of Turku shows that quasars can form even in the absence of galaxy interactions.
An international team of astronomers observed the second one of the two supermassive black holes circling each other in an active galaxy OJ 287.
A new study sheds light on the bright outbursts of radiation that are created when a star is destroyed by a supermassive black hole. The outbursts do not necessarily form in the close vicinity of the black hole, but are created by tidal shocks that occur when gas from the destroyed star hits itself while circling the black hole.
The European Research Council (ERC) has awarded a Synergy Grant, named “BlackHolistic”, of 14 million Euro to a team of Dutch, British, Finnish, and Namibian astronomers to make colour movies of black holes. Researchers from the University of Turku are involved in international collaboration.
Some of the brightest objects in the sky are called blazars. They consist of a supermassive black hole feeding off material swirling around it in a disk, which can create two powerful jets perpendicular to the disk on each side. A blazar is especially bright because one of its jets of high-speed particles points straight at Earth. For decades, scientists have wondered: How do particles in these jets get accelerated to such high energies?
The researchers observed the X-ray radiation from the matter around a black hole. According to the researchers the shape and orientation of the X-ray glow support the theory, that the X-rays come from the disc-shaped material flowing into the black hole which is perpendicular to previously imaged relativistic outflows of matter called jets. These findings give a better understanding about the inner workings of black holes and how they consume mass.
Researchers from Aalto University, the University of Turku and the Finnish Centre for Astronomy with ESO were part of the international research group in taking a revolutionary picture.
Radio observations made by Metsähovi, Finland’s only astronomical radio observatory, and Caltech's Owens Valley Radio Observatory (OVRO) in California have revealed that radiation from the remote PKS 2131-021 quasar is subject to periodic variation. Researchers at the University of Turku participated in the analysis of the observational data.