Abell 576 galaxies magnitude and velocities

Because (1) the low-dispersion galaxy population is no more luminous than the global population and (2) the evidence for a cooling flow is weak, we suggest that the core of A576 may contain the remnants of a lower mass subcluster. We examine the cluster mass, baryon fraction, and luminosity function. The cluster virial mass varies significantly depending on the galaxy sample used.

Consistency between the hydrostatic and virial estimators can be achieved if (1) the gas temperature at r~1h^-1^Mpc is T_X_~8keV (the best-fit value) and (2) several velocity outliers are excluded from the virial calculation. Although the best-fit Schechter function parameters and the ratio of galaxy to gas mass in A576 are typical of other clusters, the baryon fraction is relatively low. Using the consistent cluster binding mass, we show that the gas mass fraction is ~3h^-3/2^% and the baryon fraction is ~4%.