Data analysis activities of the RMKI Virgo Group

Data analysis activities of the RMKI Virgo Group

Noise and Wiener filter studies

In case when the detector noise is not perfectly white, the optimal matched filtering is not realized by simply taking the cross-correlation of the signal pattern and the measured time series, but by correctly implementing the Wiener filter, depending also on the actual time series. We investigate the gain in signal to noise ratio when implementing the Wiener filter correctly. Our preferred approach is based on performing the Wiener filtering in time domain, using unbiased statistical estimators of the necessary correlation functions, and on the Neumann series expansion for deconvolution (for this, see J.Phys. A39 (2006) 13621).

(Andras Laszlo)

Calculating spinning eccentric GW templates

In the post-Newtonian formalism the spacetime is assumed to be split into two parts, the near and wave zones. The field equations for the perturbed Minkowski metric are solved in both regions. As a result of the calculations, the radiation field in the wave zone is expressed in terms of integrals over the source (the source multipole moments). For the special case of compact binary systems the source integrals are evaluated and the relative acceleration of the orbiting bodies is given e.g. in Kidder up to the leading order radiation reaction terms. We integrate these equations of motion and spin precession numerically with the 4th order Runge-Kutta method, and express the gravitational waveforms for spinning eccentric binaries from the general form of the radiation field.

(Matyas Vasuth, Peter Csizmadia)

Implementing new templates, efficiency test

The calculated new waveforms are transformed into ninja format and are injected into the detector signal. We use the already existing template banks to see with what efficiency the new injections are discovered with the old non-spinning, circular waveforms.

(Gergely Debreczeni)