In a recent study published in The Astrophysical Journal, an international team of researchers led by the Center for Astrophysics | Harvard & Smithsonian (CfA) observe the remains of a star swallowed by a black hole being spewed out of that very same black hole that devoured it. This study holds the potential to help us better understand how black holes function, both before and after they consume something as massive as a star.
"This caught us completely by surprise -- no one has ever seen anything like this before," says Yvette Cendes, a research associate at CfA, and lead author of the study. Dr. Mendes compares this phenomenon to “burping” after a meal.
However, this “burping” occurred several years after the star was consumed, which leaves the research team puzzled. What the team can be sure of is the material being ejected is traveling at half the speed of light.
When radio data obtained from the Very Large Array (VLA) in New Mexico observed data to indicate the black hole had somewhere come back to life after swallowing its meal, Cendes and company rushed to investigate further.
"We applied for Director's Discretionary Time on multiple telescopes, which is when you find something so unexpected, you can't wait for the normal cycle of telescope proposals to observe it," explains Dr. Cendes. "All the applications were immediately accepted."
Stars being consumed by black holes are known as tidal disruption events (TDEs), but the outflow event is known to occur more quickly than a few years.
"It's as if this black hole has started abruptly burping out a bunch of material from the star it ate years ago," explains Dr. Cendes.
"This is the first time that we have witnessed such a long delay between the feeding and the outflow," says Dr. Edo Berger, who is a professor of astronomy at Harvard University and the CfA, and a co-author on the study. "The next step is to explore whether this actually happens more regularly and we have simply not been looking at TDEs late enough in their evolution."
Sources: The Astrophysical Journal
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