Data analysis for the search of a stochastic gravitational background

The stochastic background of gravitational waves is noise, produced by a high number of uncorrelated events.
It may be of cosmological origin or of astrophysical origin.

The sensitivity of the detectors to this background is a function of
their noise spectral amplitude (1/sqrt(Hz)) and of the square root of observation time and frequency bandwidth .
At least two detectors, properly located and aligned, are needed to do a measure.

Read this note on the stochastic g.w. search !

We have done a crosscorrelation analysis of the data recorded by the gravitational wave (g.w.) resonant detectors Explorer and Nautilus, to obtain information on the g.w. stochastic background. We have found that the quantity

Omega_gw(f), that measures the closure of the Universe, is less than 60, at 907.20 +- 0.05 Hz, where a factor 10 is obtained by the crosscorrelation analysis and a factor 6 takes into account the distance (of the order of 600 km) between Explorer and Nautilus. This is the first experiment where the data of two g.w. cryogenic resonant detectors are crosscorrelated.

The procedure and the results have been published (Astronomy Astroph. 351,811-814 (1999)) and
this is the PDF file and this is Fig.1 this is Fig. 2

Another paper on results obtained using the data of Explorer and Nautilus is: "Upper limit for g.w. stochastic background with the Explorer and Nautilus resonant detectors" (Physics Letters B 385 (1996))
click here !

Papers describing the analysis procedures and the limit we may reach are in:

Stochastic background of g.w. (2000, Proc. GWDAW Rome)

Resonant antennas for stochastic background measurements (CQG,1997)

Spectral tecqniques for stochastic background measurements (1997, Proc. GWDAW, Orsay)

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