Non-thermal emission from massive YSOs. Exploring the spectrum at high energies

TL;DR

This paper discusses the detection and modeling of non-thermal high-energy emissions from massive young stellar objects, highlighting their potential as gamma-ray sources due to relativistic particle acceleration in outflows.

Contribution

It introduces a comprehensive model for high-energy radiation from massive YSOs, considering both leptonic and hadronic processes at outflow termination shocks.

Findings

Detection of non-thermal radio emission in star forming regions

Proposed model predicts gamma-ray emission from YSOs

Relativistic particles accelerated at outflow shocks

Abstract

Thermal radio and X-ray emission has been traditionally associated with the formation of stars. However, in recent years, non-thermal radiation from massive star forming regions has been detected. Synchrotron radio emission and non-thermal X-rays from the outflows of massive young stellar objects (YSOs) provide evidence of the presence of relativistic particles in these sources. In YSOs, the acceleration of particles is likely produced where the thermal jet impacts on the surrounding medium and a shock wave is formed. Thus, particles might be accelerated up to relativistic energies through a Fermi-I type mechanism. Relativistic electrons and protons can interact with thermal particles and photons, producing then gamma-rays. These energetic photons could be detected by the new generation of instruments, making massive YSOs a new population of gamma-ray surces. In the present contribution we briefly describe some massive star forming regions from which non-thermal radio emission has been detected. In addition, we present a general model for high-energy radiation from the massive YSOs embedded in these regions. We take into account both leptonic and hadronic interactions of particles accelerated at the termination points of the collimated outflows ejected from the protostar.