Active galactic nuclei and star birth

Active galactic nuclei and star birth

The UGC 5101 Galaxy contains an active compact core, which releases abundant radiation and is capable of stimulating the birth of stars. In the photo of the Hubble telescope, the tidal tail on the left indicates that we are facing a pair of merging galaxies

Most galaxies in the centers place a supermassive black hole (SMBH). But scientists still do not fully understand the role they play in the formation and evolution of galaxies. Many agree that there should be a strong correlation between the SMBH and its brightness, stellar mass and stellar motions in the galaxy.

These correlations are applied both in local galaxies and in earlier cosmic epochs. However, despite advances in the study of SMBH, it is still unclear how they affect native galaxies. In some scenarios, they suppress the birth of stars by feeding on material. In others, on the contrary, they enhance the appearance of new stars by activating the interstellar medium. To understand the issue, used a variety of computer simulations. The birth of stars is one of the main markers of galactic growth. Scientists tried to measure star formation, comparing the speed of birth with luminosity. But the radiation from the region around a supermassive black hole with accretion (active galactic nucleus - AGN) can be easily confused with a hint of a star birth. X-rays can be used to determine a separate contribution from AGN, but dust and other effects affect the performance.

A team of astronomers investigated 323 galaxies with AGN, powerful X-rays and the active birth of new stars (determined using far-infrared rays). Galaxies are distant, so their light travels to us a distance of 2-11 billion years. Statistical analysis of the sample shows that, on average, the AGN is about 20% of the infrared luminosity, but sometimes it can rise to 90%. It turns out that the supermassive hole does not suppress the stellar birth in the galaxy, but increases with the replenishment of new stars.

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