  We investigate the variations of broadband luminosities of low and
intermediate redshift galaxies due to the stochastic nature of the neutral
hydrogen present in form of Ly-alpha absorbers in the intergalactic medium.
This effect is caused by variations in the distribution and properties
(redshift, column density, Doppler parameter) of the absorbers along different
lines-of-sight out to a given redshift. Using a set of observationally
constrained redshift-, column density- and Doppler parameter distributions we
perform Monte Carlo simulations for a large number of lines-of-sight towards
galaxies at a given redshift z and calculate attenuated FUV/NUV magnitudes and
corresponding 1-, 2- and 3-sigma variations. We predict significant variations
in luminosity ranging from -0.22 to +0.48 magnitudes at the 1-sigma level for
galaxies at z=1.5 in GALEX data.
