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Abstract Here we describe a new study of the supernova remnants (SNRs) and SNR candidates in nearby face-on spiral galaxy M83, based primarily on MUSE integral field spectroscopy. Our revised catalog of SNR candidates in M83 has 366 objects, 81 of which are reported here for the first time. Of these, 229 lie within the MUSE observation region, 160 of which have spectra with [Sii]:Hαratios exceeding 0.4, the value generally accepted as confirmation that an emission nebula is shock-heated. Combined with 51 SNR candidates outside the MUSE region with high [Sii]:Hαratios, there are 211 spectroscopically confirmed SNRs in M83, the largest number of confirmed SNRs in any external galaxy. MUSE’s combination of relatively high spectral resolution and broad wavelength coverage has allowed us to explore two other properties of SNRs that could serve as the basis of future SNR searches. Specifically, most of the objects identified as SNRs on the basis of [Sii]:Hαratios exhibit more velocity broadening and lower ratios of [Siii]:[Sii] emission than Hiiregions. A search for nebulae with the very broad emission lines expected from young, rapidly expanding remnants revealed none, except for the previously identified B12-174a. The SNRs identified in M83 are, with few exceptions, middle-aged interstellar medium (ISM) dominated ones. Smaller-diameter candidates show a larger range of velocity broadening and a larger range of gas densities than the larger-diameter objects, as expected if the SNRs expanding into denser gas brighten and then fade from view at smaller diameters than those expanding into a more tenuous ISM.
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High-resolution Spectra of Supernova Remnants in M83
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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- Award ID(s):
- 1714281
- PAR ID:
- 10392211
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 943
- Issue:
- 1
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 15
- Size(s):
- Article No. 15
- Sponsoring Org:
- National Science Foundation
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