Astrophysique à Haute Energie

Les premiers résultats de la mission spatiale ASIM pour étudier les Terrestrial Gamma Ray Flashes, et les faisceaux d'électrons associés

Les orages sont des sources de phénomènes transitoires intenses, dans le domaine visible, mais également dans le domaine des rayons X et gamma. Une petite fraction des décharges se produisant dans les orages est en effet capable de générer des flashes de photons X et gamma appelés "Terrestrial Gamma Ray Flashes" (TGF). Ils sont produits typique autour de 15 kilomètres d'altitude, avec une durée de 200 microsecondes, et des énergies allant jusqu'à 30-40 MeV.

Magnetar birth as engine of extreme stellar explosions

The birth of a neutron star with an extremely strong magnetic field, called a magnetar, has emerged as a promising scenario to power a variety of outstanding explosive events. This includes gamma-ray bursts, supernovae with extreme kinetic energies called hypernovae and super-luminous supernovae. The origin of these extreme magnetic fields (of the order of 10^15 Gauss) remains, however, obscure and requires an amplification over several orders of magnitude during the formation of the neutron star.

The many faces of pulsars 

Pulsars are rapidly rotating, strongly magnetised neutron stars, 
emitting flashes of non-thermal radiation covering up to eighteen decades of 
energy in the electromagnetic spectrum.
They are powerful tools used in physics, astronomy and even cosmology.
I’ll review their observational status and prospects for the future.
I’ll then present current models of high-energy processes as well as new
theoretical developments in modeling pulsars and their wind zones.

The supernova remnant pevatron population in the TeV sky

The supernova remnant hypothesis for the origin of Galactic cosmic rays has
passed several tests, but the firm identification of a supernova remnant
pevatron, considered to be a decisive step to prove the hypothesis, is still
missing.
While a lot of hope has been placed in next-generation instruments
operating in the multi-TeV range, it is possible that current gamma-ray
instruments, operating in the TeV range, could pinpoint these objects or, most
likely, identify a number of promising targets for instruments of next

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