The distant red galaxy neighbour population of 1< z < 2 QSOs and optically obscured sources

BORNANCINI CARLOS G.; GARCÍA LAMBAS DIEGO

Malargue, Mendoza

Congreso; 50 Reunión Anual de la Asociación Argentina de Astronomía; 2007

Asociación Argentina de Astronomía

We study the Distant Red Galaxy (DRG, J-K_s>2.3) neighbour population of Quasi Stellar Objects (QSOs) selected from the Sloan Digital Sky Survey (SDSS) in the redshift range  1< z <2. We perform a similar analysis for optically obscured AGNs (i.e. with a limiting magnitude I > 24) detected in the mid-infrared (24 microns) with the Spitzer Space Telescope and a mean redshift z ~ 2.2in the Flamingos Extragalactic Survey (FLAMEX).We present results on the cross--correlation function of DRGs around QSOs and optically faint mid-infrared sources.The corresponding correlation length obtained for the QSO sample targets is r_0=5.4+/-1.6 Mpc. For the optically obscured galaxy sample we find r_0=8.9+/-1.4 Mpc.These results indicate that optically faint obscured sources are located in denser environment of evolved red galaxies compare to QSOs.