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Improved optical spectrophotometry of supernova remnants in M33Optical spectra of SNRs in M33 have been used to investigate abundance gradients and SNR evolution in this galaxy. Abundances of O, N, and S are derived from the spectra using new shock models by Dopita et al. (1984). The results for N and S show abundance gradients similar to those in NGC 300 and the Galaxy. The O abundances may be affected by possible contamination from H II regions and low-velocity shocks. Electron densities derived from the forbidden S II 6717 A/6731 A line ratio are used with a pressure equilibrium argument to estimate the initial explosion energy for each SNR. Evolutionary models for the remnants are investigated, and the distribution of the number of remnants with diameter is found to be consistent with free expansion of the SNRs to diameters of about 26 pc. The results may also be consistent with Sedov evolution if the ranges of initial supernova energies and surrounding interstellar medium densities are large enough.
Document ID
19850044840
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Blair, W. P. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Kirshner, R. P. (Michigan, University Ann Arbor, MI, United States)
Date Acquired
August 12, 2013
Publication Date
February 15, 1985
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 289
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NAG5-87
CONTRACT_GRANT: NSF AST-83-09496
Distribution Limits
Public
Copyright
Other