Non thermal emission from microquasar/ISM interaction

TL;DR

This paper presents an analytical and simulation-based model of non-thermal radiation produced by microquasar jets interacting with the interstellar medium, predicting detectable radio and gamma-ray emissions.

Contribution

It introduces a self-similar analytical model combined with hydrodynamical simulations to study non-thermal emission from microquasar jet interactions.

Findings

Radio emissions from jet termination regions are detectable with current instruments.

X-ray luminosities are moderate and the emission region is compact.

Gamma-ray emissions could be detectable by next-generation instruments.

Abstract

The interaction of microquasar jets with their environment can produce non-thermal radiation as is the case for extragalactic outflows impacting on their surroundings. We have developed an analytical model based on those successfully applied to extragalactic sources. The jet is taken to be a supersonic and mildly relativistic hydrodynamical outflow. We focus on the jet/shocked medium structure when being in its adiabatic phase, and assume that it grows in a self-similar way. We calculate the fluxes and spectra of the radiation produced via synchrotron, Inverse Compton and relativistic Bremsstrahlung processes by electrons accelerated in strong shocks. A hydrodynamical simulation is also performed to further investigate the jet interaction with the environment and check the physical parameters used in the analytical model. We conclude that microquasar jet termination regions could be detectable at radio wavelengths for current instruments sensitive to arcminute scales while at X-rays the expected luminosities are moderate, although the emitter is more compact than the radio one. The radiation at gamma-ray energies may be within the detection limits of the next generation of satellite and ground-based instruments.