PSZ2 cluster candidates. III.

We complement these LP15 spectroscopic results with Sloan Digital Sky Survey archival data and other observations from a previous program (ITP13-08), and present a catalogue of 388 clusters and groups of galaxies including estimates of their velocity dispersion. The majority of them (356) are optical counterparts of PSZ2 sources. A subset of 297 of those clusters are used to construct the M_SZ_ - M_dyn_ scaling relation based on the estimated SZ mass from Planck measurements and our dynamical mass estimates.

We discuss and correct for different statistical and physical biases in the estimation of the masses, such as the Eddington bias when estimating M_SZ_ and the aperture and the number of galaxies used to calculate M_dyn_. The SZ-to-dynamical mass ratio for those 297 PSZ2 clusters is (1-B)=0.80+/-0.04(stat)+/-0.05(sys), with only marginal evidence for a possible mass dependence for this factor. Our value is consistent with previous results in the literature, but is associated with a significantly smaller uncertainty due to the use of the largest sample size for this type of study.