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B. Buckalew, R. Dufour (Rice U.), H. Casteneda (UNAM--OAN)
We report selected results of an extensive optical imaging and spectroscopic study of Wolf-Rayet Galaxies using observations obtained from Kitt Peak National Observatory and San Pedro Martir Observatorio Astronomico Nacional. To date, imagery and/or spectroscopic data on thirty-seven Wolf-Rayet galaxies have been obtained. Twenty-six of the galaxies have CCD imagery taken with UBVRI filters and/or filters focussing on H\alpha, H\beta, [O~{\sc iii}], [O~{\sc ii}], or He~{\sc ii} emission lines. Twenty-six galaxies have longslit CCD spectra at low (5~Å) or moderate (3-1~Å) resolution covering the \lambda\lambda3,400--7,500 wavelength range. We report in detail the results of imagery and spectroscopic analysis of Mrk 1236, NGC 1569, NGC 6764, and NGC 7714. These galaxies were chosen because they have extensive imagery in both narrow and broad band filters, as well as spectra at both low and moderate resolution. From the broad band imagery data, we have produced color-index and color-color maps of these galaxies. From the narrow band data, we have produced reddening (H\alpha/H\beta) and ionization ([O~{\sc iii}]/H\beta) maps. From the spatially resolved spectra, we have derived electron temperatures and densities, and chemical and ionic abundances of various H~{\sc ii} regions in the galaxies with and without a population of Wolf-Rayet stars. In addition, we compare the colors, intrinsic reddening, and ionization of OB associations with known Wolf-Rayet stars compared to similar associations without Wolf-Rayet stars. The intent of this study is to see whether the large number of Wolf-Rayet stars contained in starburst regions has affected the ionization structure, abundances, or dust content of the surrounding H~{\sc ii} regions. The colors of the various OB associations with and without Wolf-Rayet stars will be used to constrain observationally the age range during which such associations contain Wolf-Rayet stars.
This research is supported by a NASA-GSRP fellowship to B.B.(NGT 2-52252).
The author(s) of this abstract have provided an email address for comments about the abstract: brent@regultra.rice.edu