What affects the process of feeding black holes?

What affects the process of feeding black holes?

A group of researchers was able to determine that the rate of variability of light emitted by a material upon absorption by supermassive black holes in galactic centers is determined by the accretion rate. That is, the main factor is the amount of “eaten” material.

Over time, the light emitted into the hole material changes greatly, but without a stable pattern, which indicates variability. Scientists know that there is a change, but there is no exact reason why this happens. For example, when reviewing other objects, like stars and galaxies without active nuclei, it is clear that their brightness is constant for a certain time. However, active-core galaxies exhibit an unpredictable rise and fall in brightness.

The researchers tried to study how the amplitude of change of the emitted light is related to the average brightness of the active galactic nucleus, the mass of the supermassive black hole and the accretion rate (the amount of material consumed per hole per year). The analysis showed that among the indicators the most significant should be considered the latter.

Scientists have found that only the accretion rate is able to predict the variability of such objects. That is, you need to take into account the amount of material entering the supermassive black hole. If she is on a diet or overeating, then light variability will determine the situation. The less it eats, the more seriously it changes. It is important to understand whether this physical mechanism is an integral characteristic of all galaxies with active galactic nuclei. The new findings challenge the old paradigm, indicating that the amplitude of light variability depends on the brightness of the active core. The situation has changed due to the SDSS data, which measured the parameters in 2000 similar objects. In addition, it turned out to produce high-quality light curves for a large sample of objects, so you could independently investigate the variability of each object.

The data used in the work were obtained from the QUEST survey (La Silla) from 2010-2015, where 5 extragalactic fields were observed. As well as spectral information from SDSS (Sloan Digital Celestial Survey). Scientists hope to further explore the time scale of the variability of active galactic nuclei, and for this you need to have light curves with a coverage of more than 10 years.

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