Impact of the CMB on the evolution of AGNs and their relativisitc jets at the highest redshifts

Radio-Loud (RL/jetted) AGNs are among the brightest sources at all wavelengths and are usually associated with the densest regions of the Universe. Their relativistic jets can affect both the SMBH growth and the surrounding IGM and have been observed extending up to Mega-parsec scale. After 20 years from the detection of the first extended kilo-parsec extragalactic jet in the X-rays, the mechanism responsible for their high-energy emission at these scales is still under debate. At the same time, it was recently found that the cosmological evolution of the jetted AGN population significantly differs when observed in the X-ray or the radio band. Their X-ray space density peaks at much earlier times (z~4) when compared to their radio one (z~2), which would imply a different redshift evolution of the typical X-ray luminosities with respect to the radio ones. In this talk I will show how the Inverse Compton interaction between the CMB photons and the electrons within relativistic jets (IC/CMB) can nicely solve both these problems. Our results are based on statistical studies performed on the largest well-defined samples available to date (up to z~5) and the detailed study of the most distant X-ray jet resolved to date (z=6.1). Finally, I will also present our efforts to expand current samples at even higher redshift, where the effect of the CMB is stronger. By exploiting the most recent radio surveys, in less than one year we were able to discover three new RL AGNs at z>6, where only four were known before.