Supermassive black holes may be the gravitational glue that binds a galaxy, but they're also a colossal puzzle. One mystery that has vexed astronomers: how do you tail black holes end up so roly-poly?
Take Sagittarius A *, the supermassive black hole at the center of the Milky Way.
A stellar core that collapses into a black hole wants to retain its pre-black hole mass in a much smaller, denser space – which means black holes gain mass by gobbling up – or accreting – matter from beyond their event horizon.
But supermassive black holes are so huge, the core collapse model lakes in stellar black holes just might not apply (especially since
They have caught one.
Now they have caught one of the supermassive black holes
Previously, it had been thought that supermassive black holes had two 'feeding' modes. The first is known as a tidal disruption event, which is violently tearing it apart and accrediting some of it.
The second is an active galactic nucleus, which is a near-continuous source of dust and gas from a disc that swirls around the black hole, like water going down a drain.
Both these events produce a specific, recognisable signature across a variety of spectra ̵
What astronomers using the ASAS-SN network has spotted an all-new type of signal, coming from an event called 2017bgt, spotted around a supermassive black hole 14 million times the mass of the Sun.
"The sudden brightening of 2017bgt is what reminiscent of a tidal disruption event," said astrophysicist Benny Trakhtenbrot of ETH Zurich.
"But we quickly realized that this time there What was unusual The first clue was an additional component of light, which had never been seen in tidal disruption events. "
He and his team collected a year's worth of data on the black hole, and finally came to the conclusion that it did not match any black hole feeding events observed before.
What they saw was the optical and ultraviolet emission increased by about 50 percent for a year, and the X-ray emission by several factors, before dying down.
They believe that it may have a lot of gas, more than a lot of it, but it seems to be more or less necessary 19659003] "An [active galactic nucleus] is like getting rained on – a constant trickle that might vary in intensity, but loads for a while it might be more intense than rain, "explained astronomer Andy Howell of Las Cumbres Observatory.
" How the hell did nature produce that? Black holes are even weirder than we thought. "
What is not just a freak occurrence?
"We hope to detect many more such events, and to follow them with several telescopes working in tandem," said astrophysicist Iair Arcavi of Tel Aviv University.
"The team has been researched."
The team's research has been completed published in the journal Nature Astronomy .