Palestrante: Dr. Bruno Arsioli (UNICAMP)

Resumo: Jetted Active Galactic Nuclei (AGN) are the most powerful astrophysical sources continuously emitting radiation along the entire electromagnetic spectrum, as probed from Radio up to TeV gamma-rays. An overview about AGNs will be shown, with focus to its particular family of Blazars.

Blazars are dominant in the extragalactic gamma-ray sky especially at very high energies (VHE, E > 100 GeV), which is starting to be probed with increasing sensitivity and resolution power. The upcoming generation of VHE observatories are driven by the many open questions still to address. Among them: The acceleration mechanism in jetted AGNS and its jet composition; The possibility of probing regions close to super massive black holes for tests of general relativity; The existence of a putative gammaray background and its unknown origin; The possible correlation of extreme gamma-ray sources with astroparticles like PeV neutrinos and ultra high energy cosmic rays; The transparence of the universe to VHE photons as a probe for axion-like particles; The use of VHE sources as a probe for the spectral energy distribution of the extragalactic background light (EBL) specially in infra-red;

In this vast context, observations made with the Fermi-LAT satellite along its ~ 9 years of operation had made available to the scientific community an unique all-sky database covering many decades in energy, from tens of MeV up to hundreds of GeVs.

Given the importance of jetted AGNs for VHE astrophysics, the search for new gamma-ray blazars is key to build a better description of the gamma-ray sky. In my current work, the Fermi-LAT database is used for an all-sky survey looking for signatures of new gamma-ray sources based on a multifrequency approach. Motivations and current status of this work will be discussed, showing results and the main insights they bring us.