Numerical simulations of supernova remnants in turbulent molecular clouds

Abstract

Core-collapse supernova (SN) explosions may occur in the highly inhomogeneous molecular clouds (MCs) in which their progenitors were born. We perform a series of 3dimensional hydrodynamic simulations to model the interaction between an individual supernova remnant (SNR) and a turbulent MC medium, in order to investigate possible observational evidence for the turbulent structure of MCs. We find that the properties of SNRs are mainly controlled by the mean density of the surrounding medium, while a SNR in a more turbulent medium with higher supersonic turbulent Mach number shows lower interior temperature, lower radial momentum, and dimmer X-ray emission compared to one in a less turbulent medium with the same mean density. We compare our simulations to observed SNRs, in particular, to W44, W28 and IC 443. We estimate that the mean density of the ambient medium is ∼ 10 cm −3 for W44 and W28. The MC in front of IC 443 has a density of ∼ 100 cm −3 . We also predict that the ambient MC of W44 is more turbulent than that of W28 and IC 443. The ambient medium of W44 and W28 has significantly lower average density than that of the host giant MC. This result may be related to the stellar feedback from the SNRs' progenitors. Alternatively, SNe may occur close to the interface between molecular gas and lower density atomic gas. The region of shocked MC is then relatively small and the breakout into the low density atomic gas comprises most of the SNR volume.

Supernovae feedback propagation: the role of turbulence

“…This is likely due to their turbulence resulting 10 2 10 1 10 0 10 1 10 2 10 3 10 4 10 5 n [cm 3 ] from the decay of a one-off generated random velocity field, as opposed to our media originating from a series of forcings over several turnover times (recall Section 2). We also note that the scales considered in Zhang & Chevalier (2019) are smaller than that of this study. While the initial velocity dispersions in our simulations are in line with Larson (1981) scalings, the higher values they use cause their SNRs to encounter more energetic structures as they expand.…”

“…Conversely, Zhang & Chevalier (2019) reported universal, close to spherical shapes of their SNRs, in all the turbulent media they modelled. This discrepancy with our conclusions and those of Martizzi et al (2015) probably originates from the differences between their turbulent structures and ours.…”

“…These generally found that the injected energy and momentum are largely independent of the turbulent structure. However, the SNR expands faster into low density regions, making them larger than in homogeneous media (but see Zhang & Chevalier 2019). The volume, energy and momentum of a SNR from these studies in inhomogeneous media have been implemented into spherically symmetric models, and used in simulations at larger scales.…”

“…Therefore, a set of global statistical properties may arise from different structures, depending on how the inhomogenities are generated (cf. Martizzi et al 2015;Zhang & Chevalier 2019).…”

Evolving supernova remnants in multiphase interstellar media

“…More recently, some groups have published their results of simulations that evolve SNRs on in-homogeneous media. For example: Martizzi et al (2015) or Zhang & Chevalier (2019), who focused their study on media more akin to dense molecular clouds. In the diluted media side of the spectrum, the work done by Inoue et al (2009) presents two-dimensional simulations of the evolution of SNR in a two-phase gas.…”