Gamma rays from massive protostars

Abstract

Massive protostars have associated bipolar outflows with velocities of hundreds of km/s. Such outflows produce strong shocks when interact with the ambient medium leading to regions of non-thermal radio emission. Under certain conditions, the population of relativistic particles accelerated at the terminal shocks of the protostellar jets can produce significant gamma-ray emission. We estimate the conditions necessary for high-energy emission in the non-thermal hot spots of jets associated with massive protostars embedded in dense molecular clouds. Our results show that particle-matter interactions can lead to the detection of molecular clouds hosting massive young stellar objects by the Fermi satellite at MeV-GeV energies and even by Cherenkov telescope arrays in the GeV-TeV range. Astronomy at gamma-rays can be used to probe the physical conditions in star forming regions and particle acceleration processes in the complex environment of massive molecular clouds.