Selection of short gamma-ray bursts for GeV neutrino searches

Since 2013 and the first observation of high-energy astrophysical neutrinos in the IceCube Neutrino Observatory, neutrinos constitute a new messenger to study the extreme Universe, and large neutrino telescopes have been working towards the identification of sources. While recent multi-messenger observations suggest that blazars may be the first identifiable sources of this observed neutrino flux, other source populations emitting neutrinos remain unidentified. Among promising candidates are short gamma-ray bursts (SGRBs) resulting from the merger of two neutron stars.

Study of the effect of the source environment on GeV neutrino emission in hadronic cosmic accelerators

Since 2013 and the first observation of high-energy astrophysical neutrinos in the IceCube Neutrino Observatory, neutrinos constitute a new messenger to study the extreme Universe, and large neutrino telescopes have been working towards the identification of sources. While recent multi-messenger observations suggest that blazars may be the first identifiable sources of this observed neutrino flux, other source populations emitting neutrinos remain unidentified.

Etude de l’origine de l’émission à très haute énergie au centre de notre Galaxie et connexion possible avec SgrA* notre plus proche trou noir super-massif.

Le centre de notre galaxie abrite un trou noir super-massif (SMBH) d'environ 4 106 Msol, associé à une source radio compacte appelée Sgr A*. Avec une luminosité bolométrique huit ordres de grandeur en dessous de sa luminosité d'Eddington, son émission actuelle parait très faible.

Etude du flux et de la variabilité du signal issu du Trou noir central de notre Galaxie au TeV, comparaison avec les données de HESS et perspectives avec CTA.

Le centre de notre galaxie abrite un trou noir super-massif (SMBH) d'environ 4 10⁶ Msol, associé à une source radio compacte appelée Sgr A*. Avec une luminosité bolométrique huit ordres de grandeur en dessous de sa luminosité d'Eddington, son émission actuelle parait très faible. L’émission de Sgr A* présente également des sursauts fréquents (quasi quotidiens) observés du domaine radio aux X-durs. Il apparait maintenant acquis que ces sursauts sont dus à l’accélération rapide d’électrons jusqu’à des énergies dépassant la dizaine de GeV au voisinage du trou noir.

Cosmic ray ionization and star formation in molecular clouds

Stars form due to the gravitational collapse of dense molecular clouds. The process of star formation is still not completely understood, but it is believed that a crucial parameter that regulates star formation is the ionization level in the dense cores of molecular clouds. This is because the ionization level is determining the coupling between the gas and the magneticl field, which is in turn affecting the dynamics of the collapse through magnetic pressure support.

Cosmic ray acceleration at astrophysical shocks

Cosmic rays are relativistic particles that hit continuously the Earth's atmosphere from outer space. Understanding the origin of these cosmic particles, and how they acquire their energy is one of the most important open problems in high energy astrophysics.

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.

LABORATOIRE

ASTROPARTICULE & COSMOLOGIE

Astrophysique à Haute Energie