Seeking the light from the Early Universe: a Cosmic Archaeology Tool

The launch of JWST opened an unprecedented window on the exploration of the population of early galaxies and massive accreting black holes (BHs) already in place in the high-redshift Universe. A solid theoretical framework is therefore needed to interpret current observations and constrain the evolutionary path of these extreme objects. To this aim, we developed the Cosmic Archaeology Tool (CAT), a new semi-analytical model specifically designed to reconstruct the evolution of a large statistical sample of the galaxy population over the first billion years of cosmic history. CAT is able to characterize ab initio the formation of the first stars and BHs, and to follow then the process of co-evolution between nuclear BHs and their host galaxies across cosmic times. This enables us to make predictions on the population of high-redshift galaxies and AGNs that will be observable with ongoing JWST surveys, and to characterize their properties. By combining CAT predictions with the capability of spectral synthesis models, we can also investigate the expected spectral signatures characterizing systems hosting accreting BHs and/or early stellar populations, in order to test the accuracy of standard color selection criteria and spectral diagnostics for these high-redshift sources.