English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The H.E.S.S. (High Energy Stereoscopic System) telescopes observed Coma for~8hr in a search for gamma-ray emission at energies >1TeV. The large 3.5degFWHM field of view of H.E.S.S. is ideal for viewing a range of targets atvarious sizes including the Coma cluster core, the radio-relic (1253+275) andmerger/infall (NGC 4839) regions to the southwest, and features greater thandeg away. No evidence for point-like nor extended TeV gamma-ray emission wasfound and upper limits to the TeV flux F(E) for E>1, >5, and >10TeV were setfor the Coma core and other regions. Converting these limits to an energy fluxE^2F(E) the lowest or most constraining is the E>5TeV upper limit for the Comacore (0.2deg radius) at ~8Crab flux units or ~10^{-13}ph cm^{-2} s^{-1}. Theupper limits for the Coma core were compared with a prediction for thegamma-ray emission from proton--proton interactions, the level of whichultimately scales with the mass of the Coma cluster. A direct constraint usingour most stringent limit for E>5 TeV, on the total energy content innon-thermal protons with injection energy spectrum proportional to E^{-2.1} andspatial distribution following the thermal gas in the cluster, is found to be~0.2 times the thermal energy, or ~10^{62}erg. The E>5 TeV gamma-ray thresholdin this case corresponds to cosmic-ray proton energies >50TeV. Our upper limitsrule out the most optimistic theoretical models for gamma ray emission fromclusters and complement radio observations which constrain the cosmic raycontent in clusters at significantly lower proton energies, subject toassumptions on the magnetic field strength.

Constraints on the multi-TeV particle population in the Coma Galaxy Cluster with H.E.S.S. observations