UMD: Dormant Black Hole Eats Star, Becomes X-Ray Flashlight
Posted: Wed Jun 22, 2016 8:14 pm
Dormant Black Hole Eats Star, Becomes X-Ray Flashlight
University of Maryland, College Park | 2016 June 22
X-ray Echoes of a Shredded Star Provide Close-up of 'Killer' Black Hole
NASA Goddard Space Flight Center | 2016 June 22
Relativistic Reverberation in the Accretion Flow of a Tidal Disruption Event - Erin Kara et al
http://asterisk.apod.com/viewtopic.php?t=25067
University of Maryland, College Park | 2016 June 22
UMD astronomers catch X-ray echoes of a tidal disruption event for the first time
[c][attachment=0]Tidal_disruption_art_AS_crop.jpg[/attachment][/c][hr][/hr]Roughly 90 percent of the biggest black holes in the known universe are dormant, meaning that they are not actively devouring matter and, consequently, not giving off any light or other radiation. But sometimes a star wanders too close to a dormant black hole and the ensuing feeding frenzy, known as a tidal disruption event, sets off spectacular fireworks.
Astronomers from the University of Maryland and the University of Michigan are the first to document X-rays bouncing around deep within the walls of a once-dormant black hole’s newly formed accretion disk—the giant, puffy cloud of shredded star stuff circling the black hole, waiting for its turn to be swallowed up—following a tidal disruption event. Using these data, the researchers discerned the shape and activity of the accretion disk near a supermassive black hole named Swift J1644+57.
This marks the first time such detailed observations have been made for a dormant supermassive black hole. In addition, the team’s methodology could open the door to reliable measurements of black hole spin in the near future. ...
The accretion disk has an effect somewhat like the reflective shield behind a flashlight bulb, reflecting, amplifying and focusing the radiation. The fact that X-rays can originate deep within the accretion disk of a tidal disruption event is surprising, according to Kara. Conventional wisdom among astronomers has long held that, during a tidal disruption event, high-energy X-rays are created further from the black hole in the relativistic jets—huge beams of particles ejected by the black hole and accelerated to nearly the speed of light. But seeing X-ray emissions bouncing off the walls of the inner accretion disk has cast a new light on this assumption. ...
X-ray Echoes of a Shredded Star Provide Close-up of 'Killer' Black Hole
NASA Goddard Space Flight Center | 2016 June 22
Relativistic Reverberation in the Accretion Flow of a Tidal Disruption Event - Erin Kara et al
- Nature (online 22 June 2016) DOI: 10.1038/nature18007
http://asterisk.apod.com/viewtopic.php?t=25067