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Paper: Abundances in Spiral Bulges: Comparisons with Ellipticals
Volume: 147, Abundance Profiles: Diagnostic Tools for Galaxy History
Page: 26
Authors: Sansom, Anne E.; Proctor, Robert N.; Reid, Neill
Abstract: We present line-strength measurements for four spiral bulges observed with the Palomar 5m telescope. These data are compared with published indices and their profiles in elliptical galaxies. We detect strong lines in the centres of bulges, as strong as those in the centres of ellipticals. However from plots of Mg_2 versus <Fe> we find that, unlike ellipticals, spiral bulges are consistent with chemical models with solar abundance ratios across the bulges. This suggests that the star formation rate was slower in bulges than in ellipticals. Steep profiles are seen in some cases, for example the metallicity sensitive C4668 index shows a sharp central peak in the bulge of the Sa NGC 3623, reminiscent of the sub-structures seen in some elliptical and S0 galaxies.
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