2013MNRAS.434.1939A

We study the spatial orientations of angular momentum vectors of galaxies in six rotating clusters (A954, A1139, A1399, A2162, A2169 and A2366) that show a single number-density peak around the cluster centre with a spatial segregation of high- and low-velocity galaxies. The positions, position angles and inclination angles are used to covert two-dimensional observed parameters into three-dimensional angular momentum vectors of the galaxy. The expected isotropic distribution curves are determined by running numerical simulations. The chi-square, autocorrelation, Fourier, Kolmogorov-Smirnov and Kuiper V tests are carried out in order to examine non-random effects in the expected isotropic distributions. In general a random orientation of angular momentum vectors of galaxies is found in all six rotating clusters supporting hierarchy model of galaxy formation. It is found that the vanishing angular momenta is preferred by the rotating clusters which are in dynamical equilibrium and have larger value of velocity dispersion. Possible explanations of the results will be discussed.