2014/11/30 by P. Bordas, Pol Bordas, R. Yang +4 · 44 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Baryon #Cosmic ray #Fermi Gamma-ray Space Telescope #Flux (metallurgy) #Galaxy #Gamma ray #Gamma-ray bursts and supernovae #Jet (fluid) #Kinetic energy #Nebula #Nuclear physics #Physics #Proton #Stars #Telescope #astro-ph.HE
paper · pdf · doi:10.1088/2041-8205/807/1/l8
published in The Astrophysical Journal Letters 807(1), L8 (IOP Publishing) · Accepted for publication in ApJL
openalex publication_date 2015/06/26 · arxiv created 2015/06/27 · arxiv updated 2015/06/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The microquasar SS433 features the most energetic jets known in our Galaxy. A large fraction of the jet kinetic power is delivered to the surrounding W50 nebula at the jet termination shock, from which high-energy emission and cosmic-ray production have been anticipated. Here, we report on the detection of a persistent gamma-ray signal obtained with the Fermi Large Area Telescope from an unidentified source that we tentatively associate, given its 99.9% confidence level position accuracy and the lack of any other high-energy emitter counterpart in the studied region, with SS433. The obtained spectral energy distribution displays a distinct maximum at ∼250 MeV and only extends up to ∼800 MeV. We discuss the possibility that the observed gamma-ray emission is produced through proton–proton collisions at the SS433/W50 interaction regions. If the same mechanism is operating in other baryon-loaded microquasar jets, their collective contribution could represent a significant fraction of the total galactic cosmic-ray flux at GeV energies.