The last decade has seen tremendous developments in gamma-ray astronomy
with the extragalactic sky becoming highly populated by AGN.
I will highlight some of the progress in AGN research achieved over the
years, and then discuss exemplary advances in the theory of gamma-ray
loud AGN, including black-hole magnetospheric processes, the physics of
pc-scales jets, as well as particle...
Active Galactic Nuclei (AGN) are quite unique astronomical sources emitting over about 20 orders of magnitude in frequency, with different electromagnetic bands providing windows on different sub-structures and their physics. They come in a large number of flavours only partially related to intrinsic differences. I will highlight the types of sources selected by different bands, the relevant...
Ultrahigh energy cosmic rays (UHECRs), i.e., cosmic rays with energies above 10^18 eV (=1 EeV), are the most energetic particles ever observed. Their sources are still a mystery. Giant ground-based observatories, such as the Pierre Auger Observatory and the Telescope Array, have shown that the sources of UHECRs are extragalactic. The observed UHECR spectrum has subtle features that can be...
The existence of dark matter - the dominant, non-baryonic, neutral and cold matter component of our Universe - is inferred from its gravitational effects at galactic and cosmological scales, as well as from the power spectrum of the temperature anisotropies of the cosmic microwave background. Several theoretically plausible dark matter candidates, such as WIMPs, axions or primordial black...
Significant advances have been made in cosmic-ray measurements in recent years, particularly with successful space missions and long-duration balloon flights over Antarctica. The high precision data from these missions over a wide energy range led to surprising discoveries, such as an excess of positrons at high energies and hardening of the elemental spectra. These unexpected spectral...
In this review talk I will present the state-of-the-art of pulsar observations in different observing bands, from radio to very high energy gamma-rays, with a particular focus on the different emission mechanisms in place. Furthermore, I will focus on the low-B millisecond pulsars and the high-B magnetars, comparing their multi-band spectra and showing new interesting results of the past few years.
I will discuss some selected instruments, which are key for current multi-messenger results. Then I will focus on diffuse fluxes, namely the cosmogenic fluxes and galaxy fluxes, which can be better estimated through multiple messengers. I will look into more detail to some galactic sources probable cosmic-ray-gamma-ray-neutrino messengers. On extragalactic sources, I will review recent IceCube...
