General Relativity Seminar
The cross-correlation search for stochastic and continuous gravitational wave sources
Wednesday June 15, 2016 16:15:00 CEST
Wednesday June 15, 2016 18:00:00 CEST
Prof. Sanjeev Dhurandhar
The cross-correlation search can be used to map the stochastic gravitational wave (GW) background, as well as track continuous wave sources such as spinning neutron stars. An astrophysical GW background will likely arise from an incoherent superposition of unmodelled and/or unresolved sources and cosmological GWbackgrounds (CGWB) are also predicted in certain scenarios. The basic statistic used is the cross-correlation between the data from a pair of detectors. In order to ‘point’ the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the GW to travel to both detectors corresponding to a source direction. Then the raw sky map of the GW background is the signal convolved with a beam response function that varies with location in the sky. The true sky map is obtained by numerically deconvolving the beam function in the integral (convolution) equation by using the maximum likelihood approach. We apply these methods to the Virgo cluster which could be "hot spot" of stochastic GW originating from rotating neutron stars which is a suitable source for this method. We then show how this method can be adapted to observe continuous wave sources such as spinning neutron stars. This method can be used as a trade-off between computational cost and sensitivity. This method can also be employed for LMXB searches such as Sco X-1. Work on how to speed up the searches is in progress.