Bursting dwarf galaxies - Implications for luminosity function, space density, and cosmological mass density

An attempt is made to estimate the true average space density of gas-rich dwarf galaxies by comparing the luminosity and size distributions of visible dwarf irregulars with a set of simulated observations of a bursting population of galaxies on which selection effects corresponding to the real observations have been imposed. The true size distribution is assumed to be a power law f(r) proportional to r exp y. A value of y = - 4.2 + or - 0.2 gives good agreement with the observed frequency distributions of luminosity, optical radius, and angular size. The same model accounts for the observed luminosity function in the Virgo cluster. The implications of this result for the true shape of the Galaxy luminosity function and the contribution to the cosmological density are discussed. 48 references.