Astrophysicists hope their method for detecting changing-look quasars (CLQs) will bring us one step closer
A quasar is an area of impressive luminosity incenter of the galaxy, powered by a supermassive black hole. It is the largest type of black hole, with billions of times the mass of our Sun. There is also a supermassive black hole at the center of the Milky Way. Quasars are formed when gaseous matter is attracted by gravitational forces to a supermassive black hole. When gas approaches it, it forms an accretion disk. Energy is released from it in the form of electromagnetic radiation, and it is this that creates the luminosity of the quasar.
Quasars that change appearance quicklyswitch between high and low luminosity states, and scientists have yet to figure out why. When the brightness decreases, the quasar becomes too dim to be seen against the backdrop of its parent galaxy. That is why it is difficult for scientists to find either him or the supermassive black hole with which he is associated.
A new detection method will allow researchersfind quasars that undergo sharp changes in luminosity, and, therefore, conduct a more complete census of supermassive black holes. The next step will be to study the causes of luminosity switching to give scientists a better understanding of the growth of supermassive black holes. In turn, this will help scientists trace the chain of events that lead to the growth of galaxies. It is the release of energy from supermassive black holes that can influence their fate.
Previous attempts to identifyCLQ-type quasars relied on variability over a wide range of wavelengths - the method of photometric variability. The problem is that it misses quasars with lower luminosity. Researchers at the University of Bath used spectroscopic data to assess changes in very small wavelength ranges. This allowed them to detect CLQ-type quasars that the photometry method had not detected. Using this technique, astrophysicists discovered four changing quasars a million light years away from Earth. All of them were too dim to be detected using photometry.
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Accretion disc is a structure that occurs inas a result of the fall of a diffuse material with a rotational moment on a massive central body. Accretion disks appear around stars in close binaries, in rotating galaxies and in protoplanetary formations.