Fermi Cygnus cocoon

Gamma-ray observations of Cygnus~X have revealed the presence of an excess of hard-spectrum gamma-ray emission, possibly related to a cocoon of freshly-accelerated particles. We seek an improved description of the gamma-ray emission from the cocoon using ~13 years of observations with the Fermi-LAT and use it to further constrain the processes and objects responsible for the young cosmic-ray population.

We develop an emission model for a large region of interest, including a description of interstellar emission from the background population of cosmic rays and recent models for other gamma-ray sources in the field. Thus, we perform an improved spectro-morphological characterisation of the residual emission including the cocoon.