Friday, May 20, 2005

GravStat 2005: Romano

Search for stochastic GWs by cross-correlating 2 GW detectors
Y = Int df s_1(f) Q(f) s_2(f)
where Q(f) is the filter. Look for Omega ~ f^alpha. Q normalized to give = Omega_0.

Split data into short segments and calculate Y. Downsample 16384 -> 1024 Hz. High-pass filter and window to reduce leakage. Calibrate in f domain. Sliding PSD estimation to eliminate bias. Remove coherent lines (nx60Hz, nx16Hz). Optimal filter for different spectral indices. H1-H2 shows broadband coherence due to acoustic coupling. B analysis with prior 1/Omega_max where
Omega_max is from previous analysis.

Marginalise over theoretical variances - estimating for observed Y. S3 H1-L1 fits theoretical variance very well. Doing search in S4 for anisotropic stochastic GW - eg center of Galaxy, Virgo cluster.

Are there more general relationships for more detectors ?

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