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Past Events
Dynamics of Fast Spinning Neutron Stars around a Massive Black Hole
| Speaker: | Prof. Kinwah Wu |
| Affiliation: | Mullard Space Science Laboratory, University College London |
| Date: | July 14, 2014 (Mon) |
| Time: | 4:00 p.m. |
| Venue: | Room 522, 5/F, Chong Yuet Ming Physics Building, HKU |
Abstract
The dynamics of strongly bound gravitational systems often show interesting complex phenomena. Fast spinning objects orbiting around a black hole would exhibit complex spin precession and orbital behaviour due to relativistic coupling. I shall show my recent work on the dynamics of two types of black hole (BH) - neutron star (NS) systems:
(1) a fast spinning NS orbiting around a BH, and
(2) a double neutron star system (DNS) orbiting around a BH (which is a hierarchical 3-body system).
In (1) spin-curvature coupling leads to non-planar NS orbits in addition to de-Sitter and Lense-Thirring precessions of the NS spin. In (2) orbit-orbit coupling induces gravito-magnetism, which manifests in complex orbital and spin dynamics of the DNS. I shall discuss applying the findings of (1), together with ms-pulsar timing, to determine masses of BHs and hence to establish a precise method for mass measurement of BHs at the lower end of M-sigma relation for spheroids in galaxies. Is shall also discuss how gravito-magnetism in DNS could be detected in pulsar timing and gravitational wave observations and possible applications of the technique developed in studying these systems in other scientific and non-scientific disciplines.
Coffee and tea will be served 20 minutes prior to the seminar.