Cosmic Background of Gravitational Waves from Rotating Neutron Stars

The extragalactic background of gravitational waves produced by tri-axial rotating neutron stars was calculated, under the assumption that the properties of the underlying pulsar population are the same of those of the galactic population, recently derived by Regimbau & de Freitas Pacheco (2000). For an equatorial ellipticity of $\epsilon$ = 10$^{-6}$, the equivalent density parameter due to gravitational waves has a maximum amplitude in the range 2$\times10^{-11}-3\times10^{-9}$, around 0.9-1.5 kHz. The main reasons affecting the theoretical predictions are discussed. This background is comparable to that produced by the ''ring-down'' emission from distorted black holes. The detection possibility of this background by a future generation of gravitational antennas is also examined.