Stefan Gillessen
Max-Planck-Inst. Extraterrestrische Physik (MPE) (Garching, Allemagne)
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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| « A gas cloud on its way towards the supermassive black hole at the Galactic Centre » |
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Stefan Gillessen |
| Measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a black hole four million times the mass of the Sun. With the exception of modest X-ray and infrared flares Sgr A* is surprisingly faint, suggesting that the accretion rate currently is very low. In 2011 we discovered a dense gas cloud approximately three times the mass of Earth that is falling into the accretion zone of Sgr A*. Our observations fully constrain the cloud's orbit. It is highly eccentric with a pericenter distance of only 3100 times the Schwarzschild radius. The pericenter passage will happen in summer 2013 and already now we can see that the cloud has begun to tidally disrupt due to the black hole's gravitational force. The cloud also is a probe for the properties of the accretion flow, and ultimately we might have a chance to see how a massive black hole is being fed. |
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vendredi 3 février 2012 - 11:00 Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |