Black hole announces itself to astronomers by ripping apart a star
A hitherto undiscovered black hole announced its presence to astronomers when it ripped apart and devoured a star that wandered too close to it.
The intermediate-mass black hole located in a dwarf galaxy a million light-years from Earth shredded the star in an occurrence that astronomers call a Tidal Disruption Event (TDE). The TDE made itself visible when it blasted out a flare of radiation so powerful that it briefly outshone every star in its dwarf galaxy home combined.
This TDE could help scientists better understand the relationship between galaxies and the black holes within them. It also provides astronomers with another intermediate black hole to study. “This discovery has created widespread excitement because we can use tidal disruption events not only to find more intermediate-mass black holes in quiet dwarf galaxies but also to measure their masses,” research co-author and UC Santa Cruz (UCSC) astronomer Ryan Foley said in a statement (opens in new tab).
Related: Black hole is ‘burping out’ a ‘spaghettified’ star it devoured years ago
The TDE flare — designated AT 2020neh (opens in new tab)— was first observed by astronomers using the Young Supernova Experiment (YSE), an astronomical survey that detects short-lived cosmic events like supernova explosions, as the black hole first began to devour the star.
The observation of this initial moment of destruction was vital in allowing an international team led by UCSC scientists and research first author and Niels Bohr Institute astronomer Charlotte Angus to measure the mass of the black hole finding it to be around between around 100,000 and 1 million times the mass of the sun. (opens in new tab)
TDEs have been successfully used to measure the mass of supermassive black holes in the past, but this is the first time they have been shown to work in documenting the masses of smaller midsized intermediate-mass black holes.
That means that the initial sighting of the incredibly fast AT 2020neh flare could provide a baseline for measuring midsized black hole masses in the future.
“The fact that we were able to capture this midsize black hole whilst it devoured a star offered us a remarkable opportunity to detect what otherwise would have been hidden from us,” Angus said. “What is more, we can use the properties of the flare itself to better understand this elusive group of middle-weight black holes, which could account for the majority of black holes in the centers of galaxies.”
This midsized class of black holes have a mass range of between 100 and 100,000 times that of the sun, making them significantly more massive than stellar-mass black holes but much smaller than the supermassive black holes that sit at the heart of most galaxies,…
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