Théorie

Gamma-ray astronomy with axion-like particles and search for intergalactic magnetic fields

The future gamma-ray experiment CTA plans to measure the fluxes of blazars in the energy range from 30 GeV to 100 TeV with sensitivity 10 times superior to present measurements. Intergalactic magnetic fields can be measured through observations of the secondary photons through time delay in blazar flairs, signatures in spectra and extended emission around the point sources.

Neutrinos, neutrino properties and dense astrophysical environments

A major progress has been made in neutrino physics after the discovery of the neutrino oscillations. Crucial questions are being addressed experimentally and should receive an answer soon, including the absolute neutrino mass and mass ordering, the existence of sterile neutrinos and of CP violation in the lepton sector. Intriguing open issues also concern how neutrinos modify their flavor in astrophysical environments.

Sur la possibilité d'étude des champs dans les espaces de Robertson-Walker à partir de R6 et problématiques associées

L'objectif de la thèse est d'étudier les possibilités d'extensions d'un formalisme permettant de considérer des équations de champs en espace-temps courbes à quatre dimensions à partir d'équations de champs dans l'espace plat R6 Plus précisément il s'agirait d'étudier le possibilité de théories de champs dans R6 muni de la métrique (+,+,-,-,-,-) et leurs restrictions, en particulier, aux espaces de Robertson-Walker. L'intérêt d'un tel formalisme étant la possibilité d'utiliser le cadre a priori plus simple d'un espace plat pour l'étude de champs classiques et quantiques. Les différents résultats obtenus dans ce cadre peuvent donner lieu à des problématiques diverses de théorie des champs ou de formalisme.

Cosmology with Gravitational Waves

The direct detection of Gravitational Waves (GWs) by the ground-based LIGO interferometers in 2015 has opened up gravitational wave astronomy in the regime of high-frequencies.  New sources have already been found – namely black-holes with masses larger than those expected from remnants of supernovae explosions and stellar evolution – and it is likely that other unexpected phenomena will be revealed by GW observations in the low redshift universe.

Search for neutrino sources of IceCube data

Recently IceCube collaboration discovered astrophysical neutrinos  of unknown origin.

 Our group  developed methods to study  both galactic and extragalactic contributions to to this signal.

Goal of this stage is to develop  model of astrophysical neutrino sources, which consistent both with neutrino and 

gamma-ray data and make predictions for  contributions of various classes of astrophysical sources

in future data of IceCube and km3 experiments

Multi-messenger sources of cosmic rays, gamma-rays and neutrinos

Astrophysical neutrinos measured by ICECUBE challenge existing models of multi-messenger sources. Goal of thesis is modeling of sources of cosmic rays, gamma rays and neutrinos taking into account all experimental constraints from direct measurements, KASCADE-Grande and Pierre Auger Observatory for cosmic rays, HESS, Fermi and CTA for gamma-rays and ICECUBE/km3 for neutrinos, study propagation of cosmic rays and gamma-rays in the Galaxy and intergalactic space, search for the imprints of such sources in the experimental data.

Champs quantiques en espace-temps courbe

Les mesures détaillées des anisotropies de température du rayonnement cosmique de fond (CMB) montrent que l'Univers primordial a subi une phase d'expansion accélérée : l'inflation. Il devient pressant d'assoir le paradigme de l'inflation sur des bases théoriques solides. De nombreuses questions fondamentales sont ouvertes, parmi lesquelles la compréhension des aspects quantiques de la théorie. 

Modelling astrophysical neutrinos

Modelling astrophysical neutrinos

Recently IceCube collaboration discovered astrophysical neutrinos  of unknown origin. Our group  developed methods to study  both galactic and extragalactic contributions to to this signal.  

In particular we established first evidence of Galaxy signal in IceCube data.

Goal of this stage is to develop our model of astrophysical neutrinos and make predictions for contributions of various classes of astrophysical sourcesin future data of IceCube and km3 experiments.

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