Identifying groups of high-z galaxies from incomplete spectroscopic surveys

Identifying galaxy groups from spectroscopic surveys of galaxies is crucial for studies of the galaxy-halo connection. Previous surveys at low redshifts (e.g. 2dFGRS, SDSS, GAMA) have produced large catalogs of galaxy groups, which have allowed extensive studies of both galaxy populations and host dark halos. Similar surveys at redshifts higher than unity are coming out in the next years, e.g. the Primary Focus Spectrograph (PFS) surveys, which are usually limited to low sampling rates and large cosmic variance than low-z surveys. It is chalenging to identify galaxy group out of such surveys. In this talk I will present our new works aiming to develop new group finders, optimized for high-z incomplete spectroscopic surveys and tested on a set of mock surveys that mimick the selection effects of the upcoming PFS galaxy evolution survey. We show that, with the help of supplementary photo-z catalogs, our group finder can construct a group catalog with a high completeness and purity, comparable to the group catalogs previously constructed from low-z surveys.