Population study of Galactic supernova remnants at very high γ-ray energies with H.E.S.S.
Language
en
Article de revue
This item was published in
Astronomy and Astrophysics - A&A. 2018, vol. 612, p. A3
EDP Sciences
English Abstract
Shell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to the knee of the CR spectrum at E ≈ 3 × 1015 eV. Our Milky Way galaxy hosts more than 350 SNRs ...Read more >
Shell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to the knee of the CR spectrum at E ≈ 3 × 1015 eV. Our Milky Way galaxy hosts more than 350 SNRs discovered at radio wavelengths and at high energies, of which 220 fall into the H.E.S.S. Galactic Plane Survey (HGPS) region. Of those, only 50 SNRs are coincident with a H.E.S.S source and in 8 cases the very high-energy (VHE) emission is firmly identified as an SNR. The H.E.S.S. GPS provides us with a legacy for SNR population study in VHE γ-rays and we use this rich data set to extract VHE flux upper limits from all undetected SNRs. Overall, the derived flux upper limits are not in contradiction with the canonical CR paradigm. Assuming this paradigm holds true, we can constrain typical ambient density values around shell-type SNRs to n ≤ 7 cm−3 and electron-to-proton energy fractions above 10 TeV to ϵep ≤ 5 × 10−3. Furthermore, comparisons of VHE with radio luminosities in non-interacting SNRs reveal a behaviour that is in agreement with the theory of magnetic field amplification at shell-type SNRs.Key words: gamma rays: general / ISM: supernova remnantsRead less <
English Keywords
gamma rays: general
ISM: supernova remnants
flux: upper limit
cosmic radiation: galaxy
energy: high
gamma ray: VHE
HESS
supernova
magnetic field
cosmic radiation: acceleration
cosmic radiation: spectrum
density
shell model
radio wave
electron
p
luminosity
Origin
Hal imported