Abstract

Contributed Talk - Splinter SNR

Tuesday, 10 September 2024, 14:00   (S14)

Simulations of SNRs in a magnetized multi-phase medium

Mattia Pacicco, Michael Schulreich, Dieter Breitschwerdt
Technische Universität Berlin

Supernova remnants (SNR) are the result of the interaction between stellar material ejected by supernova explosions and the surrounding interstellar medium (ISM). The shock waves produced by the explosions are responsible for heating large volumes of ISM and ultimately regulate star formation in galaxies, thus playing a crucial role in galactic evolution. The structure of the ISM and the strength of the regular magnetic field embedded in it heavily influence the evolution of these objects. Understanding and modelling how magnetic fields influence the evolution of SNRs is essential to explain the properties of these emitting shells in the sky. We run 3D high resolution magneto-hydrodynamical (MHD) simulations of SNRs expanding in both a weakly and a strongly magnetized non-homogeneus ISM. The non-homogeneity in the gas is shaped by thermal instabilities, which are ubiquitous in the ISM. Thermal instabilities, driven by plasma cooling and heating processes, bring the initially uniform ISM to a new equilibrium characterised by a multi-phase gas distribution. In this way, we add a layer of complexity to the initial conditions of the problem, while retaining a somewhat ideal and well-defined gas distribution. The dense cold spots generated by thermal instabilities can destabilise the expanding shell and favour the mixing of the cold phase with the warm interior of the remnant, leading to an overall decrease in temperature. With our simulations we explore the effects of a strong regular magnetic field (up to 50-100 micro Gauss) showing how the structure of SNRs can be heavily influenced: the magnetic field lines compressed in the shell have a stabilising effect that seems to suppress the instabilities generated by inhomogeneities. Our simulations show, however, the non-spherical symmetry of this stabilising effect. Finally, we study the X-ray emission of magnetised SNRs with a simple emission model.