PI: Bahram Mobasher, Space Telescope Science Institute, firstname.lastname@example.org
Address: 3700 San Martin Drive, Baltimore, MD 21218, U.S.A
CoI: N. Scoville/D. Thompson, Caltech
CoI: J. Mould, NOAO
CoI: P. Capak/L. Yan, Caltech/SSC
Title: Near-IR Survey of the HST-ACS COSMOS 2-Degree Field
Abstract: Our HST treasury proposal (COSMOS, PI: Nick Scoville) was recently awarded 640 orbits to perform a 2 square degree imaging survey in \it i (F814W) band. This is the first HST survey cabable of understaning the interplay between large scale structure and the formation and evolution of galaxies. Major efforts by other colabortors have obtained complementary data from the UV to the radio. This panchromatic, high resolution data set allows galaxy morphology, luminosity functions, and clustering properties to measured as a function of environment and redshift simultainously. We propose to use the wide field near-IR instruments at KPNO (FLAMINGOS) and CTIO (ISPI) 4m telescopes to survey the 2 sq. degree COSMOS field to J_AB ~ 21.7. This complements the COSMOS photometric datasets (X-ray, UV, optical, K-band and radio). The near- IR (J-band) data will significantly improve the accuracy of photometric redshifts (rms~ 0.070) for the total of ~ 2\times 10^6 galaxies in COSMOS. In particular, photometric redshifts in the range 1 < z < 2 will be improved, by removing the confusion between the Lyman break and the 4000Abreak features. This provides the necessary redshift range to study the formation and evolution of structures to the epoch of peak galaxy formation (z~ 2). Combined with available K-band data, we can select a population of very red galaxies with J-K > 2.3, expected to be very dusty, star-forming objects at 2 < z < 3 which can be compaired to Lyman Break Galaxies z~3. Like the NOAO K-band and Subaru optical data (which will be made public during the Winter AAS meeting in January), the proposed observations here will be made public as soon as they are reduced and catalogued.
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