Daily Image
11-11-2010
Today's colloquium: Supermassive black holes in galaxies: singles, binaries, and escapees
| Submitter: | Colloquium |
| Description: | There is now growing evidence that supermassive black holes reside in most galaxies, and that they play a major role in the formation and evolution of galaxies. While long-lived accretion events are the power source of active galaxies, even in the absence of a continuous gas supply, black holes reveal their presence by the occasional disruption of whole stars, producing high-energy flares of giant amplitude. Throughout the history of the universe, galaxies will merge frequently with each other, forming binary black holes at their centres, and an active search for these binaries is currently ongoing. During the final coalescence of the two black holes, linear momentum imparted by gravitational waves produces a kick, and the newly formed single black hole will recoil from the centre of its host galaxy. The presence of supermassive binary black holes and recoiling black holes has a wealth of astrophysical implications which are currently being explored including consequences for structure formation in the early universe and black hole growth, for unified models and the evolution of active galaxies, and for black hole - galaxy scaling relations. I will first review recent observations of single black holes in non-active galaxies via tidal disruption flares. I will then give an overview of the observations and high-energy signatures of massive black hole binaries and recoiling black holes, including future schemes to search for electromagnetic counterparts to their gravitational wave signals, and I will discuss astrophysical implications. |
| Copyright: | NASA/CXC |
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