Clustering and dark matter halos of ultra-massive passively evolving galaxies and passive galaxy groups at z ~ 1.6

Abstract

Using a sample of gzK selected passive galaxies at z ~ 1.6 covering an effective area of 27 deg[superscript 2], we used the clustering measurements of Ultra Massive Passively Evolving Galaxies (UMPEGs, M[subscript stellar] > 10[superscript 11.4]]M[subscript circled dot]) to determine the masses of their host dark matter halos. We measured the angular and spatial correlation function of UMPEGs and found that UMPEGs cluster more strongly than any other known galaxy population at high redshift. Comparison to the Millennium XXL simulation suggested that their halos are of mass ~ 10[superscript 14.1] h[superscript -1]M[subscript circled dot]. We found that the passive galaxy groups also reside in massive halos, perhaps even more massive than those hosting the UMPEGs. Finally extrapolating the growth of halos hosting the UMPEGs and groups to z = 0, we showed that their halos at z ~ 1.6 may evolve into massive clusters such as Virgo and Coma in the local Universe.