Small-scale microwave-background anisotropies in a universe dominated by nonrelativistic particles

Instantaneous hydrogen recombination is the premise of the present predictions of the small scale anisotropies in background cosmic radiation temperature, for the case of an early universe model that is dominated by heavy neutrinos. On the basis of the relationship established between the temperature fluctuation parameters and the correlation radius r(0) of the galaxy distribution, an r(0) value of 4.5/(100 km/sec Mpc)/H(0)/Mpc implies a fluctuation amplitude below 0.00001; the minimum fluctuation amplitude value will depend on the amplitude of the primordial density fluctuations, the current horizon distance, and the Jeans scale at the recombination epoch. 18 references