AAS 205th Meeting, 9-13 January 2005
Session 31 Evolution of Ellipticals and Dark Matter Halos
Oral, Monday, January 10, 2005, 10:00-11:30am, California

Previous   |   Session 31   |   Next

[31.02] Ultra-Deep KECK spectroscopy of early-type galaxies in GOODS-N

T. Treu (UCLA), R. Ellis, T. Liao (Caltech), P. van Dokkum (Yale), DEEP2 Collaboration

We present the first result of a spectroscopic follow-up of 250 early-type galaxies in the GOODS-N field. Ultra deep Keck spectra (6-12 hrs) are used to derive stellar velocity dispersion and, together with GOODS photometry, to measure the evolution of the Fundamental Plane out to z=1.2. The implied evolution of the mass to light ratio is found to depend strongly on galaxy mass. The most massive E/S0 are old and dead, while evidence for continuing star formation is found in less massive galaxies. The implication of this ``downsizing" phenomenon in terms of cosmological models of galaxy formation is briefly discussed.

Funding from Hubble Fellowship HF-01167.01 and STScI grant AR-09920.01 is gratefully acknowledged.

Previous   |   Session 31   |   Next

Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.