VOIDS IN A NEUTRINO-DOMINATED UNIVERSE

In a neutrino-dominated universe galaxies are expected to form only in large-scale sheets and filaments. Most of space should be filled by low-density regions devoid of galaxies. We use N-body simulations to estimate the size distribution for these regions for quantitative comparison with the observed voids in recent red-shift surveys. The theoretical distribution depends very weakly on the mode or epoch of galaxy formation. With very conservative assumptions we find at best marginal consistency even for cosmological parameters as extreme as OMEGA-nu = 1 and H0 = 100 km s-1 Mpc.-1 Any significant reduction in either H0 or OMEGA-nu leads to predicted void sizes much larger than those observed. This difficulty arises because the observed "voids" are rarely completely empty.