An article published in the journal “Nature Astronomy” reports a study of a so-called tidal disruption event, the destruction of a star by a black hole, in this case, an intermediate-mass black hole candidate. A team of researchers cataloged the event as AT 2020neh and studied it using the Hubble Space Telescope after its discovery, which happened thanks to the Young Supernova Experiment (YSE), a survey conducted using the Pan-STARRS telescopes. Intermediate-mass black holes are rare, at least as far as we know today, so each candidate discovered can offer new information, including on the possibility that they are precursors of supermassive black holes.
About 850 million light-years from Earth, the dwarf galaxy SDSS J152120.07+140410.5 isn’t particularly interesting but the YSE survey, which began almost exactly three years ago to look for supernovae and other transient astrophysical events, discovered something exceptional inside it. These are the emissions, in the center of the image, generated by a star that got too close to a black hole and started getting slowly destroyed.
The one classified as AT 2020neh is not the first known case of what is technically called a tidal disruption event. However, in this case, the culprit seems to be an intermediate-mass black hole, which makes this event very interesting.
Few intermediate-mass black hole candidates have been discovered, so it’s difficult to say whether they are truly rare or simply the ones surrounded by accretion disks that betray their presence are rare. Discovering a candidate thanks to a tidal disruption event is a stroke of luck because in theory, the time it takes to increase its emissions’ brightness is related to its mass. In short, by studying the AT 2020neh event it should be possible to obtain more information on a type of black hole of which we still know very little.
Generally, galaxies have a supermassive black hole at their center but there’s still no certainty about the formation mechanisms of this extreme object. Intermediate-mass black holes could be precursors and may be easier to find in dwarf galaxies. The merger of dwarf galaxies and consequently the merger of their intermediate-mass black holes could lead to the birth of a supermassive black hole.
This study also provides some useful hints for future searches for intermediate-mass black holes. Searching for tidal disruption events, using data from the YSE survey or other observations, may be one way to find them and study their characteristics to test theories about their relationship to their host galaxies and supermassive black holes.
