IAU00707
Presentation type requested: EITHER
THE CHILEAN OLD GALAXY SURVEY
Patrick Hall
Princeton University Observatory
Since galaxy formation and evolution began at very early epochs, understanding them requires observing to high redshift with multiwavelength techniques sensitive to different stellar populations. Hundreds of z>2.5 galaxies have been identified via the Lyman-break signature of inter-galactic hydrogen absorption in the spectra of star-forming galaxies with high rest-frame UV fluxes. However, a Lambda=0.7 universe is 3 Gyr old at z=2.5, and so galaxies which formed most of their stars at z>2.5, or are significantly dusty, could be sufficiently red or UV-faint to be missed by this technique. Such passively evolving z>1 galaxies are difficult to select in observed-frame optical surveys -- biasing our census of the high redshift galaxy population. To reduce this bias, we are using the CTIO 4m + 10'x10' ISPI near-IR camera to conduct a deep (K<21), 1 deg^2 rest-frame optical survey for galaxies at 1<z<4, where the Balmer and 4000 Angstrom break features of moderately old stellar populations produce a strong signal in the observed I-J and/or J-K colors. By selecting galaxies more by stellar mass than by current star formation, we probe the oldest high-z galaxies, their space densities, spatial clustering, and star formation history, for the strongest constraints on structure formation models.
Willis Jon , Gawiser Eric , Triester Ezekiel , Castander Francisco , Van dokkum Pieter , Urry Meg , Maza Jose , Barrientos Felipe , Minniti Dante
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