Shocked Interstellar clouds and dust grain destruction in the LMC Supernova Remnant N132D

TL;DR

This study analyzes shocked interstellar clouds in the supernova remnant N132D in the LMC, revealing dust destruction processes, shock properties, and ISM composition through integral field spectroscopy and shock modeling.

Contribution

It provides the first detailed shock analysis of multiple clouds in N132D, determining shock parameters, dust destruction extent, and ISM chemical composition in the LMC.

Findings

Dust is effectively destroyed in faster shocks near cloud peripheries.

Refractory grain destruction varies with shock speed and location.

Cloud shocks suggest clouds were Bonnor-Ebert spheres before shock interaction.

Abstract

From integral field data we extract the optical spectra of 20 shocked clouds in the supernova remnant N132D in the Large Magellanic Cloud (LMC). Using self-consistent shock modelling, we derive the shock velocity, pre-shock cloud density and shock ram pressure in these clouds. We show that the [Fe X] and [Fe XIV] emission arises in faster, partially radiative shocks moving through the lower density gas near the periphery of the clouds. In these shocks dust has been effectively destroyed, while in the slower cloud shocks the dust destruction is incomplete until the recombination zone of the shock has been reached. These dense interstellar clouds provide a sampling of the general interstellar medium (ISM) of the LMC. Our shock analysis allows us to make a new determination of the ISM chemical composition in N, O, Ne, S, Cl and Ar, and to obtain accurate estimates of the fraction of refractory grains destroyed. From the derived cloud shock parameters, we estimate cloud masses and show that the clouds previously existed as typical self-gravitating Bonnor-Ebert spheres into which converging cloud shocks are now being driven.