27 September 2007

Speaker: Deepto Chakrabarty ( MIT )

Title: Spin and Magnetic Evolution of Millisecond X-ray Pulsars

Abstract:Accretion-powered and nuclear-powered millisecond pulsars are old neutron stars which have been spun up to rapid rotation by magnetic accretion torques. They are among the most rapidly rotating stars known, with surface velocities of order 0.1c. However, their spin frequency distribution, as observed by the Rossi X-Ray Timing Explorer (RXTE), cuts off sharply above 700 Hz, well below the presumed centrifugal break-up limit for neutron stars. The radio millisecond pulsar population appears to exhibit a similar cutoff. A variety of braking mechanisms might contribute to this cutoff, including magnetic accretion torques, magnetic dipole radiation, and even gravitational radiation from the rapidly rotating neutron star. I will discuss recent progress in exploring and understanding the millisecond pulsar spin distribution.

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