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H. Lee (University of Minnesota), D. B. Zucker (Max-Planck-Institut fuer Astronomie), E. K. Grebel (Astronomisches Institut, Universitaet Basel)
New optical spectra of eight dwarf irregular galaxies in the Centaurus A (Cen~A) group were obtained with the EFOSC2 instrument on the 3.6-m telescope at La Silla. The resulting derived nebular abundances are compared with measurements of other star-forming dwarfs in the Local Group, the Sculptor Group, and the field. Comparisons among galaxy samples were constructed with the following diagnostics: optical luminosity versus metallicity, metallicity versus gas fraction, and metallicity versus Karachentsev's tidal index. Although most of the dwarfs in our Cen~A sample have significant positive tidal indices, there appears in all diagnostic plots little difference between tidally affected galaxies (positive tidal indices) and relatively unaffected galaxies (negative tidal indices).
H.~L. acknowledges partial support from a NASA LTSARP grant NAG~5--9221 and from the University of Minnesota.
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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.