Masses of high-z galaxy hosting haloes from angular clustering and their evolution in the cold dark matter model

We examine masses of hosting haloes of two photometrically selected high-z galaxy samples: the old passively evolving galaxies (OPEGs) at z ~ 1 and Lyman break galaxies (LBGs) at z ~ 4 both taken from the Subaru/XMM-Newton Deep Survey (SXDS). The large survey area of the SXDS (1 deg²) allows us to measure the angular two-point correlation functions to a wide separation of >10 arcmin with a good statistical quality. We utilize the halo model prescription for estimating characteristic masses of hosting haloes from the measured large-scale clustering amplitudes. It is found that the hosting halo mass positively correlates with the luminosity of galaxies. Then, adopting the extended Press-Schechter (EPS) model, we compute the predictions for the mass evolution of the hosting haloes in the framework of the cold dark matter (CDM) cosmology in order to make an evolutionary link between the two galaxy samples at different redshifts and to identify their present-day descendants by letting their haloes evolve forward in time. It is found that, in the view of the mass evolution of hosting haloes in the CDM model, bright (i' <~ i'_* + 1) LBGs are consistent with being the progenitor of the OPEGs, whereas it is less likely that the LBG population, as a whole, has evolved into the OPEG population. It is also found that the present-day descendants of both the bright LBGs and OPEGs are likely to be located in massive systems such as groups of galaxies or clusters of galaxies. Finally, we estimate the hosting halo mass of local early-type galaxy samples from the 2dF and Sloan Digital Sky Survey (SDSS) based on the halo model, and it turns out that their expected characteristic mass of hosting haloes is in good agreement with the EPS predictions for the descendant's mass of both the bright LBGs and OPEGs.

Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

E-mail: hamanatk@cc.nao.ac.jp ‡

Hubble fellow.