O seminário do Grupo de Astronomia Extragaláctica será apresentado por Ulisses Barres de Almeida (CBPF).
Probing the Extragalactic Universe with Gamma-Rays and the Future CTA
Extragalactic environments such as AGN, relativistic jets, galaxy clusters, as well as GRBs, all offer excellent conditions for efficient particle acceleration in shocks, turbulence and magnetic reconnection events. All these objetcs are potential sources of VHE gamma-rays, with energies above 100 GeV. As of now, over 50 active galaxies and extragalactic jets have been detected in the VHE range by ground-based gamma-ray telescopes such as H.E.S.S., MAGIC and VERITAS, but many more are expeted from the next generation instrumento, the Cherenkov Telescope Array (CTA). CTA is also expected to expand the class of extragalactic objects detected at VHE to include galaxy clusters and GRBs. Apart from studying the astrophysical sources themselves, the observation of gamma-rays of TeV energies can be used as cosmological probes, for measuring the EBL and searching for signatures of cold dark matter particle decay or anihilation, which are expected to radiate above a few hundred GeVs. Ultimately, the observation of VHE gamma-rays from distant sources can also be a valuable tool to probe exotic particle physics, such as testing Lorentz Invariance at the Planck Scale and searching for axions. In this lecture I will introduce all the potentialities which are involved for extragalactic research with gamma-rays and the CTA.