NOAO >   Observing Info >   Approved Programs >   2003B-0362

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Proposal Information for 2003B-0362


PI: Pieter G. van Dokkum, Yale University, dokkum@astro.yale.edu
Address: Astronomy Department, PO Box 208101, New Haven, CT 06520-8101, USA

CoI: Marijn Franx, Leiden University
CoI: Ryan Quadri, Yale University

Title: Multislit Near-IR Spectroscopy of Red Galaxies at z>2

Abstract: Using extremely deep VLT/ISAAC imaging we have discovered a significant population of galaxies at z>2 with rest-frame optical colors similar to normal nearby galaxies. The galaxies have a high surface density on the sky, and can be selected efficiently by their red J_s-K_s colors. They may be the oldest galaxies yet identified at z>2, and could be the progenitors of massive early-type galaxies. Although bright in the NIR most are very faint in optical passbands, which makes spectroscopic follow-up difficult. There are 21 galaxies with J_s-K_s>2.3 and K_s<21 in the 5\farcm 4 \times 5\farcm 4 field centered on the foreground z=0.83 cluster MS 1054-03, but so far redshifts have only been obtained for six galaxies. Building on successful single slit observations of several of these galaxies with Keck/NIRSPEC we propose to obtain deep multislit NIR spectroscopy with Flamingos of the full sample of J_s-K_s selected galaxies to K_s=21 in the MS 1054-03 field, with the following goals: 1) measure redshifts from rest-frame optical emission lines, 2) measure star formation rates from H(alpha) or H(beta), 3) constrain the dust content from comparing H(alpha) to H(beta) and/or the rest-frame UV continuum emission, and 4) correct the observed broad band fluxes for the contribution of line emission, to improve the modelling of their stellar populations. The exquisite VLT imaging in this field and the high surface density of targets fully exploit the unique capabilities of Flamingos.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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