Particle Acceleration in the Cygnus Star Forming Region

  • Dec. 16, 2019, 2:00 pm
  • Curia II
  • Binita Hona, Michigan Technological University

Massive stars were postulated as sources of cosmic rays (CRs) in our Galaxy since more than three decades ago. GeV photons have been observed by Fermi-LAT from the star-forming region of Cygnus X, showing that young CRs up to TeV are produced and are interacting with the ambient gas and radiation fields. However, the role of these objects in accelerating very high Galactic CRs remains unknown. Using 1038 days of HAWC data, we detect the Cygnus superbubble at a significance level of ~12 sigma with maximum photon energies above 100 TeV. Based on the spectrum and morphology of gamma-rays, and the non-detection of radio and X-ray photons from this region, we conclude that the gamma-rays are consistent with a hadronic origin. We find a spectral softening above 1 TeV, which can either be due to the leakage of CRs from the superbubble or an upper limit to the energy of particle acceleration by the stellar winds.