Astronomers may have just witnessed the first few moments of a black hole’s existence.
A weirdly bright and brief blast dubbed “The Cow,” which researchers first spotted last June, was likely generated by a newborn black hole or superdense stellar corpse called a neutron star, a new study reports.
“Based on its X-ray and UV [ultraviolet] emission, ‘The Cow’ may appear to have been caused by a black hole devouring a white dwarf,” study lead author Raffaella Margutti, an assistant professor of physics and astronomy at Northwestern University in Illinois, said in a statement. (White dwarfs are the compact cores left over when relatively small stars like our sun die. The most-massive stars die in violent supernova explosions, with their remnants collapsing into denser-still neutron stars or black holes.) [Watch: Did Munching Black Hole Trigger ‘Cow’ Explosion in Space?]
“But further observations of other wavelengths across the spectrum led to our interpretation that ‘The Cow’ is actually the formation of an accreting black hole or neutron star,” Margutti added. “We know from theory that black holes and neutron stars form when a star dies, but we’ve never seen them right after they are born. Never.”
The Cow was a relatively nearby event: It flared up about 200 million light-years from Earth, in the Hercules constellation. Astronomers discovered the outburst using the Asteroid Terrestrial-impact Last Alert System (ATLAS), a pair of survey telescopes in Hawaii. (The event’s nickname stems from its formal designation, AT2018cow, the last three letters of which were produced using a randomized formula.)
The Cow intrigued researchers from the start. It was incredibly bright — 10 to 100 times brighter than typical supernovae — and surprisingly brief, fading away after a mere two weeks or so.