Measuring Black Hole Spin

Prof. Ramesh Narayan

Abstract

An astrophysical black hole is completely described with just two parameters: its mass and its dimensionless spin. A few dozen black holes have mass estimates, but until recently none had a reliable spin estimate. The first spins have now been measured for black holes in X-ray binaries. The talk will describe the method used to make these measurements and will discuss implications of the results obtained so far.

About the talk

Measuring Black Hole Spin
Prof. Ramesh Narayan
Harvard-Smithsonian Center for Astrophysics, USA
Thursday May 19, 2011
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About the speaker

Ramesh Narayan, is the Thomas Dudley Cabot professor for Natural Sciences at the Harvard-Smithsonian Center for Astrophysics. In 2006 he was elected Fellow of the Royal Society and in 2010 was elected Fellow of the American Association for the Advancement of Science.

Prof. Ramesh grew up in Chennai has emulating his celebrated father, Prof. G. N. Ramachandran F.R.S (1922-2001), who was elected Fellow of the Royal Society way back in 1977. This is the first instance where a father-son duo from India has been accorded this rare honour.

Prof. Ramesh is internationally recognised for his contribution in understanding Black Holes and has led research at the Harvard University in this area for the past 30 years. His work suggests a fundamental difference to earlier Black Hole studies. It strongly confirms the existence of the "event horizon", the one-way membrane around a black hole, which "vacuums up" energy from its surroundings. Prof. Ramesh says, "Watching matter flowing into a black hole is like sitting upstream of a waterfall and looking at the water seemingly vanish over the
edge."

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