IIHE Invited seminar: Results and prospects in atmospheric electricity studies at the Pierre Auger Observatory

The Pierre Auger Observatory, beyond its primary focus on cosmic rays, also yields valuable results in cosmogeophysics. Over the past decade, its fluorescence detector (FD) has captured ELVES, light emissions from the upper mesosphere caused by lightning. Exploiting high time resolution, we validated model predictions on double and triple ELVES. Moreover, the FD traces hinted at observing other transient luminous events (TLEs), such as halos, promoting the installation of a dedicated camera in December 2023 to detect their optical counterparts. It has registered several SPRITES and the first ELVES. The surface detector captures Cherenkov signals from TGFs, complementing FD with near-field cosmogeophysics data. The time resolution of the order of tens of ns and the possibility to sample the whole TGF footprint unlike in the other experiments designed for TGF detection allows us to constrain production mechanisms.

Roberta Colalillo is a researcher at the University of Napoli “Federico II”. Her research activity is focused on the study of ultra-high-energy cosmic rays, gamma rays and atmospheric electricity phenomena. In particular, she has been working on several analyses at the Pierre Auger Observatory, such as photon search and mass composition. Now, she is task leader of the CosmoGeoPhysics task of the Auger Collaboration, whose main topics are the study of TGF (Terrestrial Gamma-ray Flashes), TLE (Transient Luminous Events), and the modulation of low- energy cosmic rays due to solar activity. She is also member of the SWGO Collaboration. The Southern Wide-field Gamma-ray Observatory will be a water-Cherenkov detector array to study gamma rays in the energy range from 100s of GeV up to the PeV scale, covering the galactic center and the southern hemisphere. Moreover, she is contributing to the development of CrystalEye, an innovative detector to study gamma rays from space in the energy range from 10 KeV to 10 MeV. Finally, she deals with outreach activities for students and common people interested in science.