Stochastic background from coalescences of neutron star - Neutron star binaries

In this work, numerical simulations were used to investigate the gravitational stochastic background produced by coalescences of double neutron star systems occurring up to z similar to 5. The cosmic coalescence rate was derived from Monte Carlo methods using the probability distributions for massive binaries to form and for a coalescence to occur in a given redshift. A truly continuous background is produced by events located only beyond the critical redshift z(*) = 0.23. Events occurring in the redshift interval 0.027 < z < 0: 23 give rise to a "popcorn'' noise, while those closer than z 0: 027 produce a shot noise. The gravitational density parameter Omega(gw) for the continuous background reaches a maximum around 670 Hz with an amplitude of 1.1 x 10(-9), while the popcorn noise has an amplitude about 1 order of magnitude higher and the maximum occurs around a frequency of 1.2 kHz. The signal is below the sensitivity of the first generation of detectors but could be detectable by the next generation of ground-based interferometers. Correlating two coincident advanced LIGO detectors or two EGO interferometers, the expected S/N are respectively 0.5 and 10.