Multimessenger Astronomy with High-Energy Neutrinos and Gamma Rays

Federica Bradascio (IJCLab)

For more than a decade, multi-messenger astrophysics has opened new windows onto the most energetic phenomena in the Universe. This field combines complementary messengers such as electromagnetic radiation ranging from radio waves to gamma rays, neutrinos, and gravitational waves, in order to probe the physical processes powering cosmic accelerators. In this presentation, I will focus on two key messengers: high-energy neutrinos and gamma rays. I will review recent advances in multi-messenger studies based on IceCube neutrino observations, with particular emphasis on the role of active galactic nuclei (AGN) cores as potential neutrino sources. Finally, I will present results from coordinated multiwavelength target-of-opportunity campaigns performed by H.E.S.S., showing how rapid follow-up observations can shed light on the connection between neutrino and gamma-ray emission.