NOAO >   Observing Info >   Approved Programs >   2006A-0359

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Proposal Information for 2006A-0359


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

CoI: Mariska Kriek, Leiden / Yale
CoI: Ryan Quadri, Yale
CoI: Marijn Franx, Leiden
CoI: Ivo Labbe, OCIW, Pasadena
CoI: Eric Gawiser, Yale
CoI: Paulina Lira, Universidad de Chile
CoI: Danilo Marchesini, Yale
CoI: Sune Toft, Yale
CoI: Greg Rudnick, NOAO
CoI: Garth Illingworth, UC Santa Cruz

Title: A Public GNIRS Survey of Massive Galaxies at z~ 2.5

Abstract: Using very deep near-infrared imaging we have recently uncovered a substantial population of galaxies at z>2 with red rest-frame optical colors, complementary to the well known UV-bright Lyman break galaxies. These red galaxies make up 73% of the mass at the high mass end (M >10^11 \rm M_\odot) at 2<z<3. However, as they are faint in the UV, these red galaxies are normally missed in spectroscopically confirmed samples of high-redshift galaxies. To obtain a full census of the universe at z~2.5, we have started in 2005A a public near- infrared spectroscopic survey of mass-selected galaxies at 2.1<z<2.7. Our first results are very promising and show that GNIRS is uniquely capable of obtaining an unbiased sample of massive galaxies. The 4 first spectra of our mass-selected sample, obtained in May 2005, look very different from previous samples of UV-selected samples. Emission lines like H(alpha) an [OIII] are very faint or absent, and the spectra are best fitted by evolved stellar population models. To test if the majority of the massive galaxies at z~2.5 are already ``red and dead'', and to elucidate the nature of massive galaxies in the young universe, we propose to extent our sample to 30 massive galaxies. Our public survey was selected as a GNIRS Key Science Program in 2005A, and we now request time to complete the project.


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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