The latest findings on the star-eating black hole
Phil Evans, an X-ray astronomer in England and frequent guest blogger for Geeked On Goddard, sends us this report on some exciting new findings of the NASA Swift observatory.
Back in March this year the Swift satellite detected a massive explosion in space. That in itself is nothing new. Indeed, it’s what Swift was designed to do. But, as I posted back in April, this one was a bit strange. Whereas Gamma Ray Bursts — Swift’s bread-and-butter (how cool, by the way, to be describing the most powerful explosions known in such an off-hand way) — explode and then fade away, this object flared up again, and again and then a fourth time, and even now is a bright source of X-rays.
So what was it? As I noted in that post, just 3 weeks after the event, a consensus has already formed that this was an extremely rare event: a star being torn apart by a black hole. Two papers have today (August 25) been published in the journal Nature, arguing for this interpretation, one of them led by Prof. David Burrows — the head of the X-ray Telescope (XRT) team on the Swift satellite. Here is a University of Leicester press release on the discovery.
The aftermath of such an event has been seen before (occasionally), but only well after the event, where all that can be seen are the last dregs of material being gobbled up: the black hole licking its lips, if you like. With Swift, for the first time, we’ve now seen the process actually starting, the black hole taking its first bite.
And, in doing so, we found something new: the light we saw can’t be explained by the standard models of a star being torn apart by a black hole. Incidentally, the black hole was a few million times more massive than the Sun!
Instead, the process must have resulted in the light coming out along a narrow ‘jet’ of material. Keen followers of Swift will notice that this is also how Gamma Ray Bursts emit their light.
Setting GRBs aside, jets from black holes at the center of a galaxy are a very common phenomenon, seen in Active Galactic Nucleii for example, but we’ve never seen such a jet actually ‘turn on’, until now. This once again highlights how awesome it is to working on Swift. At any moment I could be interrupted by an SMS from the spacecraft. Maybe it will be ‘only’ a huge explosion from the other side of the universe. Or maybe it will be something completely new.
Follow Phil Evans on twitter: @swift_phil
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OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.
