Dr. Ajello’s research focuses on current topics of high-energy astrophysics, cosmology and astro-particle physics. There is a lot to be discovered about our Universe and even more about the most extreme environments in the Universe, where nature harnesses energies far beyond anything possible on Earth. Cosmology, particle physics, high-energy astrophysics and gravitational physics have tremendously progressed in the last decade. The intense research activities taking place at the cross road of these disciplines are enhanced by the opportunities that new facilities have opened up. Our group uses the Fermi gamma-ray space telescope, NuSTAR (the nuclear spectroscopic telescope array), and the Swift satellite (and many others) to unveil the mystery behind some of nature’s most powerful phenomena.