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Proposal Information for 2010A-0062

PI: Arjun Dey, NOAO, dey@noao.edu
Address: 950 N. Cherry Ave., Tucson, AZ 85719, USA

CoI: Naveen Reddy, NOAO
CoI: Moire Prescott, UC Santa Barbara
CoI: Lei Xu, Steward Observatory
CoI: Mark Brodwin, CfA

Title: Probing the Low-Mass End of the Galaxy Mass Function at z~2: A Survey for Low-z Ly(alpha) Emitters

Abstract: The steep low-luminosity end of the galaxy luminosity function at high-redshift implies that low luminosity galaxies may contribute significantly to the mass and star-formation density of the universe at early epochs. Lyman alpha emitting galaxies (LAEs) are powerful probes of the low-luminosity end of the luminosity function, and are used to place constraints on the reionization epoch. Thus far, LAE studies have focused primarily on high redshifts (z~3-7) where the physical nature and large-scale context of LAEs remain largely unconstrained. In 2007A we undertook a pilot imaging search (in ~0.9 deg^2) for LAEs at 1.8<z<2.0, the lowest redshift survey of its kind, and detected a sample of ~500 high equivalent width LAEs. In 2008A we spectroscopically confirmed 20 candidates, thus verifying the selection method. We are now surveying for z\ltsim 2 LAEs in 4 fields with existing deep Spitzer and multiwavelength data. We are assigned time in Nov '09 for 2 fields, and propose to complete our survey by targeting the 2 remaining fields in 2010A. The deep near-/mid-IR data in these fields will provide robust \it measurements of the LAE stellar masses and thereby quantify the importance of the LAE phase at different galaxy mass and luminosity scales. This is a key step in understanding how such galaxies evolve with time. Measurement of the low-z LAE auto- and cross-correlation functions (with other populations at similar redshifts) will provide constraints on the halo masses of the LAEs.

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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