Séminaire, par Fabio Acero
Mercredi 7 mai 2014, 14:30, salle Daniel Chalonge (entresol)
Fate (a.k.a. the laws of physics) has something dramatic in store for the end of the life cycle of massive stars. In the aftermath of this cataclysmic stellar explosion, a vast zoology of source type is observed such as Supernova Remnants (SNRs), pulsar wind nebulae, pulsars and ‘zombie’ pulsars. Due to high velocity shock-waves and high magnetic field, an efficient particle acceleration is noticed in those objects which are believed to be the main sources of Galactic cosmic rays.
The Fermi Gamma-ray Space Telescope is providing, since 2008, a survey of the whole sky in the GeV gamma-ray energy range with unprecedented sensitivity and angular resolution. Those observations, combined with TeV gamma-ray observations from ground Cherenkov telescopes have shed new light on many types of those Galactic particle accelerators rising from the stellar graveyard.
In combination with a wide range of multi-wavelength data, this permits the first systematic study of SNRs including GeV data, allowing us to classify SNRs and to separate effects of evolution and ambient environment. In combination with multi-wavelength data, we can constrain emission models of the underlying particle populations, allowing us to quantify SNRs' aggregate contribution to Galactic cosmic rays.
I will present a selection of GeV and TeV results and progress towards the 1st Fermi-LAT SNR catalog. A particular emphasis will be given to the role of the ambient environment (carved by the massive progenitor) in the time evolution of the particle acceleration and gamma-ray emission.
Particle acceleration in the stellar graveyard and interaction with the interstellar medium
Fate (a.k.a. the laws of physics) has something dramatic in store for the end of the life cycle of massive stars. In the aftermath of this cataclysmic stellar explosion, a vast zoology of source type is observed such as Supernova Remnants (SNRs), pulsar wind nebulae, pulsars and ‘zombie’ pulsars. Due to high velocity shock-waves and high magnetic field, an efficient particle acceleration is noticed in those objects which are believed to be the main sources of Galactic cosmic rays.
The Fermi Gamma-ray Space Telescope is providing, since 2008, a survey of the whole sky in the GeV gamma-ray energy range with unprecedented sensitivity and angular resolution. Those observations, combined with TeV gamma-ray observations from ground Cherenkov telescopes have shed new light on many types of those Galactic particle accelerators rising from the stellar graveyard.
In combination with a wide range of multi-wavelength data, this permits the first systematic study of SNRs including GeV data, allowing us to classify SNRs and to separate effects of evolution and ambient environment. In combination with multi-wavelength data, we can constrain emission models of the underlying particle populations, allowing us to quantify SNRs' aggregate contribution to Galactic cosmic rays.
I will present a selection of GeV and TeV results and progress towards the 1st Fermi-LAT SNR catalog. A particular emphasis will be given to the role of the ambient environment (carved by the massive progenitor) in the time evolution of the particle acceleration and gamma-ray emission.