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Abstract In order to better characterize the rich supernova remnant (SNR) population of M83 (NGC 5236), we have obtained high-resolution (∼85 km s−1) 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 SN 1957D. Most of the SNRs and SNR candidates have [Sii]:Hαratios 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 [Sii]:Hαratios, about half of which have emission lines that show velocity broadening greater than 100 km s−1, providing a kinematic confirmation that they are SNRs and not Hiiregions. Looking at the entire sample, we find a strong correlation between velocity widths and the line ratios of [Oi]λ6300:Hα, [Nii]λ6584:Hα, and [Sii]λλ6716, 6731:Hα. The density-sensitive [Sii]λ6716:λ6731 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.
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Properties of supernova remnants in SIGNALS galaxies – I. NGC 6822 and M33
ABSTRACT We present a spatially resolved study of the kinematical properties of known supernova remnants (SNRs) in the nearest galaxies of the SIGNALS survey, namely NGC 6822 (one object) and M33 (163 objects), based on data obtained with the SITELLE imaging Fourier transform spectrometer at the Canada–France–Hawaii Telescope. The purpose of this paper is to provide a better scheme of identification for extragalactic SNRs and, in particular, to distinguish between H ii regions and SNRs. For that we have used diagrams which involve both the [S ii]/H$$\alpha$$ ratio and the velocity dispersion ($$\sigma$$). We also introduce a new parameter, $$\xi = {[\rm S\, {\small II}] \over H\alpha } \times \sigma$$, which enhances still the contrast between SNRs and the rest of the ionized gas. More than 90 per cent of the SNRs in our entire sample show an integrated [S ii]/H$$\alpha$$ ratio larger than the canonical value (0.4). 86 per cent of the SNRs present in our field show a significant velocity dispersion. The spectral resolution of our observations allows us to observe the complex velocity structure of some SNRs.
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- Award ID(s):
- 2109124
- PAR ID:
- 10538150
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 533
- Issue:
- 3
- ISSN:
- 0035-8711
- Format(s):
- Medium: X Size: p. 2677-2704
- Size(s):
- p. 2677-2704
- Sponsoring Org:
- National Science Foundation
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