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Cosmic Messengers: Binary Black Holes and Gravitational Waves

Joan Centrella
Chief, Gravitational Astrophysics Laboratory
NASA Goddard Space Flight Center


The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, 
we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns.

For more than 30 years, scientists have tried to compute these wave patterns.  However, their computer codes have been plagued by problems that caused them to crash.
This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs.  This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing
these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by the space based gravitational wave detector LISA.

Short Biographical Sketch
Joan Centrella received her PhD from Cambridge University, where she was a student at the Institute of Astronomy. Following postdoctoral appointments at the University of Texas and the University of Illinois, she joined the faculty of Drexel University in the Physics Department. In 2001, she moved to NASA's Goddard Space Flight Center to join their newly-formed gravitational wave astrophysics group, where she leads their source modeling and numerical relativity effort in support of LISA. In 2004 she became head of the Gravitational Astrophysics Laboratory, which encompasses the gravitational wave and theoretical astrophysics groups at Goddard. Her research interests include black hole mergers, gravitational waves, numerical relativity, structure formation and cosmology.
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