Astrophysique à Haute Energie

Superbubbles and the origin of cosmic rays

The origin of PeV cosmic rays is a crucial issue in cosmic ray physics. The chemical composition of cosmic rays is dominated by protons below a particle energy of ~1 PeV, while heavier nuclei become important above it. This, together with the evidence that the transition between galactic and extragalactic cosmic rays takes place at particle energies largely exceeding the PeV, implies that the sources of galactic cosmic rays must be proton PeVatrons  

Galactic cosmic ray propagation and the antiparticle spectrum

Cosmic rays are high energy particles reaching our planet, whose spectrum  ranges from sub GeV up to 10^10 GeV energies. The bulk of the observed cosmic rays, probably up to PeV energies, is likely of galactic origin and is thought to be accelerated at supernova remnant shocks and to propagate diffusively through the Galaxy. The acceleration mechanism, the escape of accelerated particles from the sources and their subsequent propagation toward us and out of the Galaxy, are all pieces of the same complex puzzle, namely the origin of cosmic rays. A fascinating and yet not understood aspect of

La Galaxie au-delà du TeV avec H.E.S.S.-2 et CTA

L'expérience H.E.S.S.-2 (High Energy Stereoscopic System) [1] est un réseau de télescopes Tcherenkov  mesurant des rayons gamma dans le domaine des très hautes énergies (au-delà de ~30GeV). Cet observatoire est un des instruments au sol les plus performants au monde : grâce à son grand champ de vue, sa bonne résolution angulaire et sa grande sensibilité il permet de détecter et d'étudier l'émission gamma de sources galactiques aux plus hautes énergies.

The GeV-TeV connection at the Galactic Center: searching for high latitude emission at the origin of the Fermi Bubbles

The center of our Galaxy hosts a Super-Massive Black Hole (SMBH). Since it has been argued that the SMBH can accelerate particles up to very high energies, its current and past activity must contribute to the population of Galactic cosmic-rays (CRs), the energetic particles that pervade the Galaxy.

Unveiling the origin of the high energy emission at the center of our Galaxy and its possible connection with the past activity of SgrA*

The center of our Galaxy hosts a Super-Massive Black Hole (SMBH). Since it has been argued that the SMBH can accelerate particles up to very high energies, its current and past activity must contribute to the population of Galactic cosmic-rays (CRs), the energetic particles that pervade the Galaxy. Ten years ago the HESS experiment has reported a bright TeV point-like source at a position compatible with that of the SMBH. After subtraction of this point source, a diffuse emission stretching over few degrees along the Galactic longitude was revealed.

Synthèse de population de nébuleuses de pulsars

L'effondrement gravitationnel qui marque la mort d'une étoile massive engendre la plupart du temps une étoile à neutron fortement magnétisée en rotation rapide: un pulsar. Comme ces événements sont rares on connaît très mal la distribution des périodes de rotation à la naissance qui peuvent aller de quelques ms à quelques centaines de ms. Les pulsars ralentissent très rapidement et leur énergie rotationnelle est convertie en un vent de particules chargées relativistes qui, une fois confinées par le milieu ambiant, créent une nébuleuse de pulsar.

Characterization of the Laser Beacon for KM3NeT/ORCA

ORCA (Oscillation Research with Cosmics in the Abyss) is the low-energy branch of KM3NeT, the next-generation neutrino Cherenkov detector currently being built in the Mediterranean Sea with the aim of measuring the neutrino mass ordering and searching for high-energy cosmic neutrino sources [1]. The ORCA detector will consist of a dense configuration of 115 vertical strings with an horizontal spacing of 20m, supporting 18 digital optical modules and anchored on the seabed off the shore of Toulon, France.

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