Black holes love to eat, but they have different table manners

This is evidenced by research conducted by astronomers from Groningen, Manchester and Pretoria using hypersensitive radio telescopes in a well-studied part of the universe. They will soon publish their findings in two articles in the Journal of International Trade Astronomy and Astrophysics.

Astronomers have been studying so-called active galaxies since the 1950s. These are galaxies with a supermassive black hole at their center that devours matter. This, among other things, leads to the release of intense radio radiation, UV rays and X-rays.

In two upcoming publications, an international team of astronomers took a closer look at all of the galaxies active in the well-studied GOODS-North region of the constellation Ursa Major. So far, the area has mainly been studied with space telescopes that have captured visible, infrared and ultraviolet light. The new observations add data from radio telescope networks, including the e-MERLIN network in England and the European VLBI network and its hub at Dwingeloo.

Photo: ESA / C. Carrow

hunger

Thanks to systematic study, three things became clear. First, it appears that in many different types of galaxies, the nucleus can be active and that black holes sometimes consume an abundance of matter, but sometimes they almost starve.

Second, the active core is sometimes associated with star formation, and sometimes it is not. If there is a star formation, it is difficult to measure the activity in the core.
And third, the active nuclei of galaxies sometimes generate radio waves and sometimes they do not. Colossal and astonishing radio structures can arise regardless of how quickly a black hole consumes its food.

According to research lead Jack Radcliffe (formerly University of Groningen, University of Manchester and Astron; now University of Pretoria, South Africa), the observations also show that radio telescopes are very suitable for mapping the black hole-eating habits of the distant universe.