We present the measurement of the projected and redshift space 2-point correlation function ( 2pcf ) of the new catalog of Chandra COSMOS-Legacy AGN at 2.9 \leq z \leq 5.5 ( \langle L _ { bol } \rangle \sim 10 ^ { 46 } erg/s ) using the generalized clustering estimator based on phot-z probability distribution functions ( Pdfs ) in addition to any available spec-z .
We model the projected 2pcf estimated using \pi _ { max } = 200 h ^ { -1 } Mpc with the 2-halo term and we derive a bias at z \sim 3.4 equal to b = 6.6 ^ { +0.60 } _ { -0.55 } , which corresponds to a typical mass of the hosting halos of log M _ { h } = 12.83 ^ { +0.12 } _ { -0.11 } h ^ { -1 } M _ { \odot } .
A similar bias is derived using the redshift-space 2pcf , modelled including the typical phot-z error \sigma _ { z } = 0.052 of our sample at z \geq 2.9 .
Once we integrate the projected 2pcf up to \pi _ { max } = 200 h ^ { -1 } Mpc , the bias of XMM and Chandra COSMOS at z=2.8 used in Allevato et al .
( 2014 ) is consistent with our results at higher redshift .
The results suggest only a slight increase of the bias factor of COSMOS AGN at z \gtrsim 3 with the typical hosting halo mass of moderate luminosity AGN almost constant with redshift and equal to logM _ { h } = 12.92 ^ { +0.13 } _ { -0.18 } at z=2.8 and log M _ { h } = 12.83 ^ { +0.12 } _ { -0.11 } at z \sim 3.4 , respectively .
The observed redshift evolution of the bias of COSMOS AGN implies that moderate luminosity AGN still inhabit group-sized halos at z \gtrsim 3 , but slightly less massive than observed in different independent studies using X-ray AGN at z \leq 2 .