Early Science Result from the Japanese Virtual Observatory : AGN and Galaxy Clustering at z = 0 . 3 to 3 . 0 ∗

We present the result of projected cross correlation analysis of AGNs and galaxies at redshifts from 0.3 to 3.0. We used the Japanese Virtual Observatory (JVO) to obtain the Subaru Suprime-Cam images and UKIDSS catalog data around known AGNs. We investigated ∼1,000 AGNs, which is about ten times larger samples than previous studies covering the redshifts larger than 0.6. We found significant excess of galaxies around the AGNs at redshifts of 0.3 to 1.8. For the lowest redshift sample (z < 0.8), we obtained correlation length of r0 ∼5 Mpc, which indicates that the AGN at these redshifts resides in a similar environment to typical local galaxies. We also obtained redshift dependence of r0 in each luminosity group, which show the AGN produced at higher redshift resides in a denser environment than the lower redshift AGN does. For AGNs at the highest redshift sample (z > 1.8), we could not obtain a significant clustering signature and put an upper limit of r0 < 17 Mpc (90% C.L.). These results are compatible with the major merger scenario which incorporates the downsizing of mass assembly.