The Cen A galaxy group: dynamical mass and missing baryons

The nearby elliptical galaxy Cen A is surrounded by a flattened system of dwarf satellite galaxies with coherent motions. Using a novel Bayesian approach, we measure the mean rotation velocity v_{\rm rot} and velocity dispersion \sigma_{\rm int} of the satellite system. We find v_{\rm rot}/\sigma_{\rm int} \simeq 0.7 indicating that... Show more