Streaming motions of galaxy clusters within 12 000 km s(-1) - III. A standardized catalogue of Fundamental Plane data

We report the construction of a new, standardized all-sky catalogue of Fund amental Plane (FP) data from early-type galaxies in clusters, for peculiar velocity applications. This catalogue is based on a compilation of spectros copic and photometric data consisting of data reported in previous papers o f this series, plus data from published sources. We compare velocity disper sion and Mg-2 line-strength data from 27 sources, and determine the correct ions that bring, all data sets on to a standardized system. For the velocit y dispersions, the corrections are typically at the level of similar to0.01 5 dex, corresponding to 5 per cent in the FP-estimated distance. The uncert ainties in these corrections, however, are considerably smaller: the new da ta obtained by our group are closely matched on to the standard system, wit h systematic uncertainties at the level of similar to0.005 dex in velocity dispersion (<2 per cent in distance). In this respect our catalogue signifi cantly improves upon previously published FP data sets. For the Mg2 line-st rength index, corrections are typically at the level of 0.01 mag, but the u ncertainties in these corrections are only <similar to>0.002 mag. A similar procedure is employed to compare photometric data from nine diffe rent sources, correcting for the average colours of early-type galaxies. We focus on the combination of parameters appearing in the FP, X-FP = log R-e - 0.32 [mu](e), where R-e and [mu](e) are the effective radius and effecti ve surface brightness, respectively. For the data sets considered here we s how that no further corrections are required to X-FP, given the typical sys tematic zero-point uncertainties per data source (0.003-0.006 dex, or 0.7-1 .4 per cent in distance). Finally, we use redshift data to assign galaxies to clusters in an objective way. We present a master catalogue of FP data for 699 galaxies in 56 clusters, t he largest high-quality data set of its kind. These data will be used in fu ture papers to determine the distances and peculiar velocities of these clu sters, and thus probe the peculiar velocity field within 12 000 km s(-1).