The search for gravitational waves with resonant detectors

An overview of experiments in the search for gravitational waves by means of resonant detectors is given. Since 1990 cryogenic resonant antennas have been in operation and data have been recorded by EXPLORER, ALLEGRO, NIOBE, NAUTILUS and AURIGA. The sensitivity for pulse detection with SNR = 1 is now h similar to 4.10(-19) (corresponding to a total energy of less than 0.001 solar masses for a source in the Galactic Center). The sensitivity for monochromatic waves is h similar to 2.10(-25) for one year of integration and (h) over tilde similar to 4.10(-19) corressponding to a total stochastic background detection. Comparison of data from Explorer and Nautilus has given 19 coincidences with an expectation of 1 1 accidental coincidences during 29.2 days of non-continuous operation. Cross-correlation analysis between Explorer and Nautilus has given an upper limit of Ohm = 60 for the ratio of gravitational wave stochastic background energy density to the energy density needed for a closed Universe, at a frequency of 900 Hz. Plans for the construction of large spherical detectors that should reach, at 1 1;Hz, a spectral sensitivity on the order of (h) over tilde similar to 7.10(-24) 1/root Hz are reported.