Abstract: Over the last three decades, we have seen remarkable progress in gamma-ray astronomy -  two new windows have been opened in the spectrum of cosmic electromagnetic radiation at the very high (VHE; 0.1-100 TeV) and ultrahigh (UHE; > 100 TeV) energies. The observations with the ground-based telescopes based on the imaging atmospheric Cherenkov technique and air shower particle detector arrays led to the discovery of hundreds of gamma-ray emitters of galactic and extragalactic origin. Many findings based on high-quality spectral, morphological, and temporal studies revealed (quite unexpectedly) that the Universe is full of TeVatrons and PeVatrons with unusual properties that challenge our current concepts and paradigms. The field's potential is not yet saturated - we anticipate another revolution in the field in the coming years. I will describe the status of the field, talk about recent achievements, and discuss the prospects of ground-based gamma-ray astronomy in the foreseeable future.

Biography: Professor Felix Aharonian obtained his PhD from the Moscow Institute of Engineering in 1979 and then worked in the Yerevan Physics Institute. In 1992, he transferred to the Max Planck Institute for Nuclear Physics in Germany and served as head of high-energy astrophysics theoretical group at the Institute from 1993 until his retirement in 2017. Since 2006, he has also served as director of the Center for Particle Astrophysics and Astrophysics at the Dublin Institute for Advanced Studies. In 2017, he was elected as an academician of the European Academy of Sciences. His research interests cover various aspects of the field of high-energy astrophysics, including the origin of cosmic rays, particle acceleration mechanisms, radiation mechanisms of high-energy phenomena, the physical processes of dense celestial bodies and multi-scale relativistic jets. Currently, he is actively participating in the LHAASO experiment.