# [Fe XIV] and [Fe XI] reveal the forward shock in SNR 1E0102.2-7219

## TL;DR

This study uses optical coronal emission lines from [Fe XIV] and [Fe XI] to identify and analyze the forward shock in the supernova remnant 1E0102, providing an alternative to X-ray observations with detailed spatial and physical insights.

## Contribution

It demonstrates the effectiveness of optical coronal lines in revealing the forward shock in SNR 1E0102, offering new observational methods beyond traditional X-ray techniques.

## Key findings

- Detection of [Fe XIV] and [Fe XI] emission in the remnant
- Identification of the forward shock location via optical emission
- Derived shock velocity between 330 and 350 km/s

## Abstract

Aims. We study the forward shock in the oxygen-rich young supernova remnant (SNR) 1E0102.2-7219 (1E0102 in short) via optical coronal emission from [Fe XIV] and [Fe XI]: emission lines which offer an alternative method to X-rays to do so. Methods. We have used the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph at the Very Large Telescope (VLT) on Cerro Paranal to obtain deep observations of SNR 1E0102 in the Small Magellanic Cloud. Our observations cover the entire extent of the remnant with a seeing limited spatial resolution of 0.7" = 0.2 pc at the distance of 1E 0102. Results. Our MUSE observations unambiguously reveal the presence of [Fe XIV] and [Fe XI] emission in 1E0102. The emission largely arises from a thin, partial ring of filaments surrounding the fast moving O-rich ejecta in the system. The brightest [Fe XIV] and [Fe XI] emission is found along the eastern and north-western sides of 1E0102, where shocks are driven into denser ISM material, while fainter emission along the northern edge reveals the location of the forward shock in lower density gas, possibly the relic stellar wind cavity. Modeling of the eastern shocks and the photoionization precursor surrounding 1E0102, we derive a pre-shock density $n_H$ = (7.4 +-1.5) cm$^{-3}$, and a shock velocity 330 km/s < $v_s$ < 350 km/s.