Massive protostars as gamma-ray sources

TL;DR

This paper investigates how massive protostars can accelerate particles to produce gamma-ray emission, suggesting that their jets and shocks could be detectable sources for gamma-ray telescopes, thus providing insights into star formation regions.

Contribution

It explores the conditions under which relativistic particles are accelerated at protostellar jet shocks, predicting gamma-ray emission detectable by current observatories.

Findings

Relativistic Bremsstrahlung and proton-proton collisions can produce detectable gamma-ray emission.

Massive protostars in dense clouds could be observed by Fermi and Cherenkov telescopes.

Gamma-ray astronomy can probe physical conditions in star-forming regions.

Abstract

Massive protostars have associated bipolar outflows with velocities of hundreds of km s$^{-1}$. Such outflows can produce strong shocks when interact with the ambient medium leading to regions of non-thermal radio emission. We aim at exploring under which conditions relativistic particles are accelerated at the terminal shocks of the protostellar jets and can produce significant gamma-ray emission. We estimate the conditions necessary for particle acceleration up to very high energies and gamma-ray production in the non-thermal hot spots of jets associated with massive protostars embedded in dense molecular clouds. We show that relativistic Bremsstrahlung and proton-proton collisions can make molecular clouds with massive young stellar objects detectable by the {\it Fermi}{} satellite at MeV-GeV energies and by Cherenkov telescope arrays in the GeV-TeV range. Gamma-ray astronomy can be used to probe the physical conditions in star forming regions and particle acceleration processes in the complex environment of massive molecular clouds.