Clustering and properties of galaxies around high redshift radio galaxies

BORNANCINI CARLOS G.; GARCÍA LAMBAS DIEGO; DE BREUCK CARLOS

Isla Margarita, Venezuela

Congreso; XII Reunión Regional Latinoamericana de la UAI; 2007

Unión Astronómica Internacional

We present measurements of the clustering properties of galaxies in the field 0.5 < z < 1.5 Ultra Steep Spectrum (USS) radio sources selected from SUMSS and NVSS surveys. We find a comoving correlation length of r_0=14.0+/-2.8 h^{-1} Mpc.  We compare our findings with those obtained in a cosmological N--body simulation populated with GALFORM semi-analytic galaxies.  We find that clusters of galaxies with masses in the range M=10^{13.4-14.2} h^{-1} M_{\sun} have a cluster--galaxy cross--correlationamplitude comparable to those found between USS hosts and galaxies. These results suggest that distant radio galaxies are excellent tracers of galaxy overdensities and pinpoint the progenitors of present day rich clusters of galaxies.