An international team led by scientists at UC Santa Cruz, the Niels Bohr Institute at the University of Copenhagen and Washington State University has identified an intermediate-mass black hole hiding in a dwarf galaxy. The black hole was spotted when it swallowed an unlucky star that drifted too close. Astronomers captured the flare using the Young Supernova Experiment (YSE), a survey designed to detect cosmic explosions and transient astrophysical events. Tidal disruption events, the bright flashes produced when a star escapes near a black hole and shreds, are a direct way of detecting massive black holes. The rise times of these flares are theoretically correlated with the mass of the black hole. In this study, the astronomers presented AT 2020neh, a candidate rapid accretion tidal disturbance event hosted by a dwarf galaxy. Co-author Ryan Foley, assistant professor of astronomy and astrophysics at UC Santa Cruz, said: “This discovery has generated widespread excitement because we can use tidal disruption events not only to find more intermediate-mass black holes in quiescent dwarf galaxies but also to measure their masses.” First author Charlotte Angus at the Niels Bohr Institute said the team’s findings provide a basis for future studies of medium-sized black holes. “The fact that we could capture this medium-sized black hole while it was devouring a star offered us a remarkable opportunity to detect what would otherwise have been hidden from us. In addition, we can use the properties of the flare itself to better understand this elusive group of intermediate-mass black holes, which could account for the majority of black holes at the centers of galaxies.” Co-author Enrico Ramirez-Ruiz, professor of astronomy and astrophysics at UCSC, and Niels Bohr, professor at the University of Copenhagen, said: “If we can understand the population of intermediate-mass black holes out there—how many there are and where they are— we can help determine whether our theories about the formation of supermassive black holes are correct.” “This is difficult to confirm because detecting intermediate-mass black holes is extremely difficult.” Journal Reference:
