High-Resolution Spectra of Supernova Remnants in M83

TL;DR

This study provides high-resolution spectra of 119 supernova remnants in M83, confirming their nature through emission line ratios and velocities, and explores correlations among spectral features and physical properties.

Contribution

It offers the first high-resolution spectral analysis of a large SNR sample in M83, confirming SNRs via velocity broadening and line ratios, and examines their physical correlations.

Findings

Over half of the SNRs show velocity broadening >100 km/s.

Strong correlations found between velocity widths and certain emission line ratios.

SNR diameter correlates with the [S II] line ratio, but not with velocity width.

Abstract

In order to better characterize the rich supernova remnant (SNR) population of M83 (NGC 5236), we have obtained high-resolution (about 85 km/s) spectra of 119 of the SNRs and SNR candidates in M83 with Gemini/GMOS, as well as new spectra of the young SNRs B12-174a and SN1957D. Most of the SNRs and SNR candidates have [S II]:H{\alpha} ratios that exceed 0.4. Combining these results with earlier studies we have carried out with MUSE and at lower spectroscopic resolution with GMOS, we have confirmed a total of 238 emission nebulae to be SNRs on the basis of their [S II]:H{\alpha} ratios, about half of which have emission lines that show velocity broadening greater than 100 km/s, providing a kinematic confirmation that they are SNRs and not H II regions. Looking at the entire sample, we find a strong correlation between velocity widths and the line ratios of [O I]{\lambda}6300:H{\alpha}, [N II]{\lambda}6584:H{\alpha} and [S II]{\lambda}{\lambda}6716,6731:H{\alpha}. The density-sensitive [S II]{\lambda}6716:{\lambda}6731 line ratio is strongly correlated with SNR diameter, but not with the velocity width. We discuss these results in the context of previously published shock models.