Testing the Limits of Particle Acceleration in Cygnus OB2 with HAWC
  Star forming regions (SFRs) have been postulated as possible sources of
cosmic rays (CRs) in our galaxy. One example of a gamma-ray source associated
with an SFR is the Fermi-LAT cocoon, an extended region of gamma-ray emission
in the Cygnus X region and attributed to a possible superbubble with freshly
accelerated CRs. Because the emission region is surrounded by ionization
fronts, it has been named the "Cygnus cocoon". CRs in the cocoon could have
originated in the OB2 association and been accelerated at the interaction sites
of stellar winds of massive O type stars. So far, there is no clear association
at TeV energies. Spectral and morphological studies of TeV gamma-ray emission
detected by the High Altitude Water Cherenkov (HAWC) observatory at the 2HWC
J2031+415 region reveal that the spectral energy distribution of the cocoon
extends from GeV to at least tens of TeV. Using HAWC data, we are able to study
the acceleration of particles to highest energies in the Cygnus OB2 SFR.
