Abstract
We use a sample of galaxies from the Sloan Digital Sky Survey (SDSS) to search for correlations between the λ spin parameter and the environment and mass of galaxies. In order to calculate the total value of λ for each observed galaxy, we employ a simple model of the dynamical structure of the galaxies which allows a rough estimate of the value of λ using only readily obtainable observables from the luminous galaxies. Use of a large volume limited sample (upwards of 11,000) allows reliable inferences of mean values and dispersions of λ distributions. We find, in agreement with some N-body cosmological simulations, no significant dependence of λ on the environmental density of the galaxies. For the case of mass, our results show a marked correlation with λ, in the sense that low mass galaxies present both higher mean values of λ and associated dispersions, than high mass galaxies. This last direct empirical result, at odds with expectations from N-body cosmological simulations, provides an interesting constraint on the mechanisms of galaxy formation and acquisition of angular momentum, a valuable test for cosmological models.
