AAS 199th meeting, Washington, DC, January 2002
Session 7. Galaxies - Surveys I
Display, Monday, January 7, 2002, 9:20am-6:30pm, Exhibit Hall

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[7.11] Line Strength Gradients in Spiral Bulges

B. K. Moorthy, J. A. Holtzman (New Mexico State University)

We present metallicity gradients in roughly a dozen spiral bulges obtained with the Double Imaging Spectrograph at the 3.5m Apache Point Observatory telescope. The goal of the project is to gain insight into the formation of central bulges in spiral galaxies. Models for bulge formation include dissipative collapse at the beginning of galaxy formation, merger events over the lifetime of the galaxy, and secular evolution with disk stars being inserted into the bulge through bar instabilities. The collapse model predicts strong metallicity gradients whereas secular evolution predicts that bulges will look like disks with minimal gradients. Mergers might cause any gradients to be washed out. We comment on the implications of our results for the different bulge formation models.

The author(s) of this abstract have provided an email address for comments about the abstract: bmoorthy@nmsu.edu

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