Long-slit optical spectroscopy of Large Magellanic Cloud radio supernova remnants

• Published in: Monthly notices of the Royal Astronomical Society 2008-01, Vol.383 (3), p.1175-1194
• Main Authors: Payne, J. L., White, G. L., Filipović, M. D.
• Format: Article
• Language: English
• Subjects: Astronomy; Chemistry; Earth, ocean, space; Exact sciences and technology; Magellanic Clouds; Radio astronomy; Spectrum analysis; supernova remnants; Supernovae
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2007.12620.x

We use long-slit spectra from shocked regions of radio supernova remnants (SNRs) in the Large Magellanic Cloud to estimate electron density and derive an average ‘metal’ abundance of 10−3.9 based on diagnostic line ratio plots. These simple diagnostics may be especially useful to determine abundances in more distant galaxies. Abundance values listed in this paper, in units of log(x/H) + 12, for nitrogen (7.3) and oxygen (8.2) agree with those reported in the literature. These estimates – which we assume to be dominated by the interstellar medium with little evolutionary interference – were obtained from spectral analysis of ∼50 per cent of known radio SNRs using the double beam spectrograph on the 2.3-m Advanced Technology Telescope at Siding Spring Observatory in Australia and the Cassegrain spectrograph on the 1.9-m Radcliffe telescope at the South African Astronomical Observatory. We also found optical evidence of shocked regions near 2 of 20 radio SNR candidates (J053620−693136 and J053731−662740), strengthening their identification as true remnants.