AAS 199th meeting, Washington, DC, January 2002
Session 78. Surveys and Evolution of Nearby Galaxies
Oral, Tuesday, January 8, 2002, 2:00-3:30pm, Jefferson West

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[78.02] The Mass-Metallicity Relationship of SDSS Galaxies

C. A. Tremonti, T. M. Heckman (Johns Hopkins), G. Kauffmann (Max-Planck Institut f\ddot{u}r Astrophysik), S. Charlot (Institut d'Astrophysique du CNRS & Max-Planck Institut f\ddot{u}r Astrophysik)

Using a sample of over 25,000 SDSS galaxies, we probe the correlation between gas-phase metal abundance and stellar mass. We compute metallicities from the strong optical emission lines of OII, H-beta, OIII, H-alpha, NII, and SII using new prescriptions based on the combined population synthesis and photo-ionization code of Charlot & Longhetti. We use the 4000 Angstrom break and the H-delta equivalent width to constrain mean stellar ages and derive stellar mass-to-light ratios.

In agreement with previous work, we find that metallicity is strongly correlated with galaxy luminosity. The correlation between metallicity and mass is even more pronounced, with the typical scatter being only 0.25 dex. Moreover, the relationship exhibits a distinct flattening near 1010 M\odot, independent of our choice of metallicity indicator. We interpret these results in the context of classic galactic wind models, where the relation between metallicity and mass in galaxies is driven by the selective loss of metals from shallow potential wells, and the turnover indicates the regime where closed-box chemical evolution models may apply.

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