Fermi Gamma-ray Space Telescope

Particle Acceleration by a Star Forming Region in the Cygnus Constellation with HAWC and Fermi-LAT

Binita Hona
(Dr. Henrike Fleischhack, Dr. Petra Huentemeyer)


Massive Star clusters have been postulated as possible sources of cosmic rays in our galaxy. One possible evidence of a gamma-ray source associated with stellar association is the Fermi-LAT cocoon, an extended region of gamma-ray emission detected by Fermi-LAT in the star forming region (SFR) of Cygnus X and attributed to a cocoon of freshly accelerated cosmic rays (CRs). One theory behind the origin of CRs in the cocoon is that they originate in the OB2 association and are accelerated at the interaction sites of stellar winds of massive O type stars. Hence, in that case, the Fermi-LAT cocoon is a superbubble. The HAWC observatory has detected a TeV gamma-ray source, 2HWC J2031+415, co-located with the cocoon. Spectral and Morphological studies of the region with HAWC and Fermi-LAT data reveal the HAWC source as a likely counterpart of the cocoon. The cocoon spectrum extends from the GeV to the TeV range. Using the combined spectral information, we are able to stu dy the particle acceleration in this SFR.