The Unusual Young Supernova Remnant Population in M83
Abstract
The face-on grand design spiral galaxy M83 (d=4.6 Mpc) is a veritable supernova factory, having generated six known SNe in less than 100 years. Hence, one might expect of order 60 or more supernova remnants (SNRs) less than a thousand years old that might shed light on the poorly understood ejecta-dominated phase of early SNR evolution, as well as many more older, ISM-dominated remnants that should still be visible. We are conducting a multi-wavelength Chandra/Hubble/ground-based campaign to find and characterize the SNRs in M83, concentrating especially on the younger population. HST/WFC3 emission-line data for seven fields covering the bulk of the bright optical disk have allowed us to identify ~50 optical SNR candidates with angular sizes below 0.5” (<11 pc), many with corresponding Chandra X-ray counterparts. However, with the singular exception of the remnant of SN1957D, we are not finding the expected population of ejecta-dominated young SNRs. Rather, most of the young SNRs appear to have quickly evolved into the radiative phase. Gemini-S GMOS spectra of selected objects confirm the lack of observed high velocities or obvious ejecta-enhancement of abundances. This unexpected result implies that the CSM/ISM environments for most young remnants in M83 are very dense, perhaps due in part to the super-solar metal abundances in much of this galaxy. We will show representative data from all relevant data sets that lead us to this conclusion. This work is supported in part by STScI grant HST-GO-12513.01-A and Chandra grant SAO-GO1-12115C to Johns Hopkins University.
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22345314B