Thursday, February 03, 2005

Seminar: John Baker on MBH mergers

John gave a lunchtime PSU simulation and sources talk remotely from Goddard. He summarized the interest in observing massive black hole mergers using LISA. Vecchio has recently argued that at least six months of observations are required to constrain important binary MBH parameters. This constraint requires that planned LISA sensitivity be improved at the low frequency (<>1e6 Msun) black holes at high (z>5) redshifts. If we can also get physical constraints from the merger/ringdown then this requirement is eased.

John also summarized recent numerical GR work. The Lazarus collaboration is working on fourth-order differencing - an approach that should provide much improved accuracy for a given amount of computation. Initial work is promising. The Goddard group is working on adaptive mesh methods to calculate the GW signal in the far-field. The most recent calculation is of a head-on BH-BH collision where the outer boundary of the calculation is at 256 M with steps in the resolution at 8, 16, ... M.

Keywords: Black holes, GR, LISA

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