An Efficient Matched Filtering Algorithm for the Detection of Continuous Gravitational Wave Signals

Neutron stars are perhaps the most promising class of gravitational wave (GW) sources, and searches for such GW signals is particularly suited to the characteristics of the GEO600 detector (see Schutz “Getting Ready for GEO600 Data” gr–qc9910033). However, the instantaneous GW frequency of such a source will evolve due to both intrinsic spindown effects and Doppler modulations induced by the motion of the Earth. Thus because of the large parameter space of likely signals, directly implemented optimal matched filtering is not computationally feasible. In response to this problem, Schutz and Papa have developed an alternative strategy: the Hough–Hierarchical search algorithm (see Schutz and Papa “End–to–End Algorithm for Hierarchical Area Searches for Long–Duration GW Sources for GEO600” gr–qc9905018). In order to carry out a blind search over a range of intrinsic GW frequencies, the following three stages must be calculated for each point in the parameter space of sky positions and intrinsic spindown parameters: