Context. Friends-of-friends algorithms are a common tool to detect galaxy groups and clusters in large survey data. In order to be as precise as possible, they have to be carefully calibrated using mock catalogues. Aims. We create an accurate and robust description of the matter distribution in the local Universe using the most up-to-date available data. This will provide the input for a specific cosmological test planned as follow-up to this work, and will be useful for general extragalactic and cosmological research. Methods. We created a set of galaxy group catalogues based on the 2MRS and SDSS DR12 galaxy samples using a friends-of-friends based group finder algorithm. The algorithm was carefully calibrated and optimised on a new set of wide-angle mock catalogues from the Millennium simulation, in order to provide accurate total mass estimates of the galaxy groups taking into account the relevant observational biases in 2MRS and SDSS. Results. We provide four different catalogues ⋆ (i) a 2MRS based group catalogue; (ii) an SDSS DR12 based group catalogue reaching out to a redshift z = 0.11 with stellar mass estimates for 70% of the galaxies; (iii) a catalogue providing additional fundamental plane distances for all groups of the SDSS catalogue that host elliptical galaxies; (iv) a catalogue of the mass distribution in the local Universe based on a combination of our 2MRS and SDSS catalogues. Conclusions. While motivated by a specific cosmological test, three of the four catalogues that we produced are well suited to act as reference databases for a variety of extragalactic and cosmological science cases. Our catalogue of fundamental plane distances for SDSS groups provides further added value to this paper.

We present a calibration of the fundamental plane using SDSS Data Release 8. We analysed about 93 000 elliptical galaxies up to z < 0.2, the largest sample used for the calibration of the fundamental plane so far. We incorporated up-to-date K-corrections and used GalaxyZoo data to classify the galaxies in our sample. We derived independent fundamental plane fits in all five Sloan filters u, g, r, i, and z. A direct fit using a volume-weighted least-squares method was applied to obtain the coefficients of the fundamental plane, which implicitly corrects for the Malmquist bias. We achieved an accuracy of 15% for the fundamental plane as a distance indicator. We provide a detailed discussion on the calibrations and their influence on the resulting fits. These re-calibrated fundamental plane relations form a well-suited anchor for large-scale peculiar-velocity studies in the nearby universe. In addition to the fundamental plane, we discuss the redshift distribution of the elliptical galaxies and their global parameters.

Context. Passive galaxies at high redshift are much smaller than equally massive early types today. If this size evolution is caused by stochastic merging processes, then a small fraction of the compact galaxies should persist until today. Up to now it has not been possible to systematically identify the existence of such objects in Sloan Digital Sky Survey (SDSS). Aims. We aim at finding potential survivors of these compact galaxies in SDSS, as targets for more detailed follow-up observations. Methods. From the virial theorem, it is expected that for a given mass, compact galaxies have stellar velocity dispersion higher than the mean owing to their smaller sizes. Therefore velocity dispersion, coupled with size (or mass), is an appropriate method of selecting relics, independent of the stellar population properties. Based on these considerations, we designed a set of criteria the use the distribution of early-type galaxies from SDSS on the log 10 (R 0 )−log 10 (σ 0 ) plane to find the most extreme objects on it. We thus selected compact massive galaxy candidates by restricting them to high velocity dispersions σ 0 > 323.2 km s −1 and small sizes R 0 < 2.18 kpc. Results. We find 76 galaxies at 0.05 < z < 0.2, which have properties that are similar to the typical quiescent galaxies at high redshift. We discuss how these galaxies relate to average present-day early-type galaxies. We study how well these galaxies fit on well-known local universe relations of early-type galaxies, such as the fundamental plane, the red sequence, or mass-size relations. As expected from the selection criteria, the candidates are located in an extreme corner of the mass-size plane. However, they do not extend as deeply into the so-called zone of exclusion as some of the red nuggets found at high redshift, since they are a factor 2−3 less massive on a given intrinsic scale size. Several of our candidates are close to the size resolution limit of SDSS, but are not so small that they are classified as point sources. We find that our candidates are systematically offset on a scaling relation compared to the average early-type galaxies, but still within the general range of other early-type galaxies. Furthermore, our candidates are similar to the mass-size range expected for passive evolution of the red nuggets from their high redshift to the present. Conclusions. The 76 selected candidates form an appropriate set of objects for further follow-up observations. They do not constitute a separate population of peculiar galaxies, but form the extreme tail of a continuous distribution of early-type galaxies. We argue that selecting a high-velocity dispersion is the best way to find analogues of compact high redshift galaxies in the local universe.