The origin of cosmic-rays remains one of the most important open questions in astrophysics. A powerful tool to study their acceleration sites are multi-messenger (photons and neutrinos) observations: wherever a cosmic-ray (a proton or an atomic nucleus) is accelerated, it interacts with its environment producing pions that then decay into photons, neutrinos and electrons.  γ and ν can escape the region and travel on geodesics to Earth, pinpointing their source in the Universe. 

This multi-messenger path to study natural particle accelerators has been opened at last with the discovery of a diffuse flux of high-energy (E ~ 100 TeV) neutrinos by the IceCube telescope in 2013. In 2022 the IceCube collaboration has reported a neutrino excess at the 4.2 sigma significance level, coincident in space with the Seyfert galaxy NGC 1068. A Seyfert galaxy is a class of Active Galactic Nuclei (AGN), the observational effect of accretion of matter onto a super-massive black hole. NGC 1068 is known to emit gamma-rays in the GeV band, but not in the TeV band.  Various models have been proposed to explain this multi-messenger emission, and all share the need for a neutrino-emitting region in the source that is opaque to gamma-rays, and located close to the central super-massive black-hole. 

The Cherenkov Telescope Array Observatory (CTAO) is the next-generation observatory for the TeV sky, currently under construction. It is expected to improve over current instruments by about a factor of 10 in sensitivity. The goal of the internship is to simulate future CTAO observations on NGC 1068 and Seyfert galaxies, testing the current models developed for NGC 1068 to determine if and with how much observing time CTAO will be able to discriminate between them and thus to put constraints on the physics of particle acceleration in AGNs.

During the internship the candidate will get familiar with TeV astronomy and CTAO, and with multi-messenger models that aim at explaining the photon and neutrino emission from AGNs. He/She will then perform simulations of future CTAO observations using the open-source Gammapy software (gammapy.org). 
The candidate will join the ANR funded COCOA-NuGETs project (https://anr.fr/fr/rechercher-sur-anrfr/?q=COCOA+NuGETs&id=1817&L=0): a funded PhD thesis project (2025-2028) is also available and represents the natural evolution of this internship (see PhD thesis offers on the APC website)