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Metallicity History of Galaxies

Metallicity History of Galaxies. 0<z<1. Lisa Kewley (IfA, U.Hawaii). Collaborators: C. Kobulnicky (U.Wyoming), M. Geller (SAO), B. Barton (UC Irvine), R. Jansen (ASU). Summary. Motivation Metallicity diagnostics Local samples:. NFGS Galaxy Pairs.

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Metallicity History of Galaxies

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  1. Metallicity History of Galaxies 0<z<1 Lisa Kewley (IfA, U.Hawaii) Collaborators: C. Kobulnicky (U.Wyoming), M. Geller (SAO), B. Barton (UC Irvine), R. Jansen (ASU)

  2. Summary • Motivation • Metallicity diagnostics • Local samples: NFGS Galaxy Pairs • Intermediate-z: GOODS • Metallicity History 0<z<1 • Future Directions

  3. Motivation 1. Metallicity history of star-forming galaxies still largely theoretical. Nagamine et al. (2001)

  4. Motivation 2. [OII] SF History K98 [OII] SFR filled = [OII] unfilled = Ha data from Teplitz et al. (2003) Our [OII] SFR log(O/H)+12~8.6 AV=1 also: Rosa-Gonzalez, Terlevich, & Terlevich (2002) Our [OII] SFR log(O/H)+12~8.8 AV=1 Kewley, Geller & Jansen (2004)

  5. Metallicity Diagnostics “R23” Kewley & Dopita (2002, ApJS, 142, 35)

  6. Metallicity Diagnostics - [NII]/Ha Kewley & Dopita (2002, ApJS, 142, 35) also: Denicolo, Terlevich & Terlevich (2002, MNRAS, 330, 69) R23 and [NII]/Ha re-parameterized Kobulnicky & Kewley (2004,ApJ, 617, 240)

  7. Local Sample: NFGS • 198 galaxies objectively selected from the CfA galaxy survey • (Davis & Peebles 1983, Huchra et al. 1983) • full range in Hubble type • full range of absolute magnitudes in CfA survey • See Jansen et al. (2000) • http://cfa-www.harvard.edu/~jansen/nfgs/nfgssample.html

  8. Local Sample: Galaxy Pairs • 502 galaxies objectively selected from the CfA • redshift catalog • (v < 2300 km/s, Dv < 1035 km/s, DD < 77 h-1 Mpc) • Nuclear spectra for ~200 galaxies in pairs • (Barton et al. 2000) • EWs + stellar population synthesis • “burst timescale’’ (Barton et al. 2003)

  9. Pairs NFGS NFGS & Galaxy Pairs Nuclear Spectra: Requires Aperture Correction

  10. Aperture Correction Correction ~ 0.13 dex but may vary between 0-0.4 dex Kewley, Geller, & Jansen 2005, PASP, 117, 227

  11. GOODS Survey: 0.3 < z< 1 • 204 galaxies with metallicity-quality spectra • Metallicities calculated using EWs • Upper R23 branch assumed • Av=1 assumed if no Ha See Kobulnicky & Kewley (2004, ApJ, 617, 240)

  12. GOODS Survey: 0.3 < z< 1 Kobulnicky & Kewley (2004, ApJ, 617, 240)

  13. GOODS Survey: 0.3 < z< 1 Kobulnicky & Kewley (2004, ApJ, 617,240)

  14. Conclusions • Galaxy pairs nuclei span larger metallicity range • than NFGS: • less enriched - dynamical mixing? • Preliminary Metallicity History • (for star-forming galaxies) • Metallicity evolution observed.... • but more work to do...

  15. Pairs GOODS assumes upper branch Future Directions: 0<z<3 LBGs: Pettini et al. (2001) Shapley et al. (2004) Kobulnicky & Koo (2000)

  16. Future Directions • Near-IR Spectra (R23 degeneracy, Av) • Modelling of emission-line selection effects • More galaxies!

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