20 April 2006

Speaker: Charles Keeton (Rutgers University)

Title:Testing Theories of Gravity with Lensing by Compact Objects

Abstract: The gravitational deflection of light provided one of the first observational confirmations of general relativity. Now I am considering how gravitational lensing can provide a stronger and more fundamental test of Einstein's theory, and of intriguing new alternatives. I will introduce a rigorous and comprehensive analytical framework for black hole lensing, and use it to make concrete predictions that are testable with current or near-future technology. Here are two examples: (1) In post-post-Newtonian theories of gravity, there are universal relations among lensing observables. Observed violations of these relations would falsify all PPN models in one fell swoop. (2) In braneworld gravity, there could be many primordial black holes in our Solar System that would be detectable via "attolensing" of gamma ray bursts.

Video of the Presentation (Talks can be viewed with RealPlayer. Free download is available from www.real.com )