Numerical simulations of radiative magnetized Herbig-Haro jets: the influence of pre-ionization from X-rays on emission lines

TL;DR

This paper uses numerical MHD simulations to study how pre-ionization from X-ray flux affects emission lines in Herbig-Haro jets, improving the match with observational data.

Contribution

It demonstrates that including X-ray induced pre-ionization in models enhances the accuracy of emission line predictions for Herbig-Haro jets.

Findings

Pre-ionization improves the match between models and observations.

X-ray flux from the central object likely causes pre-ionization.

Simulations reproduce observed emission line ratios more accurately.

Abstract

We investigate supersonic, axisymmetric magnetohydrodynamic (MHD) jets with a time-dependent injection velocity by numerical simulations with the PLUTO code. Using a comprehensive set of parameters, we explore different jet configurations in the attempt to construct models that can be directly compared to observational data of microjets. In particular, we focus our attention on the emitting properties of traveling knots and construct, at the same time, accurate line intensity ratios and surface brightness maps. Direct comparison of the resulting brightness and line intensity ratios distributions with observational data of microjets shows that a closer match can be obtained only when the jet material is pre-ionized to some degree. A very likely source for a pre-ionized medium is photoionization by X-ray flux coming from the central object.