NOAO >   Observing Info >   Approved Programs >   2010A-0481

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Proposal Information for 2010A-0481


PI: Mark Richardson, Arizona State University, Mark. L.Richardson@asu.edu
Address: School of Earth and Space Exploration, PO Box 871404, Tempe, AZ 85287-1404, USA

CoI: Emily McLinden, Arizona State University
CoI: Sangeeta Malhotra, Arizona State University
CoI: James Rhoads, Arizona State University

Title: Metallicities and kinematics of Lyman-alpha Galaxies at z=3.1

Abstract: We propose to measure the metallicities of z=3.1 \lya emitting galaxies. \lya emitters are the youngest class of high redshift galaxies, with typical ages of only 10^7 years and stellar masses of 10^7 - 10^9 \msun, even though their spatial clustering indicates halo masses of 10^11 \msun. By measuring the [OII], [OIII], and H(beta) line fluxes with NIRI, we will estimate metallicities for these galaxies for the first time ever. By doing so, we will \bf(a) supply one of the missing pieces in understanding \lya galaxies, whose stellar populations, masses of halos and ages have been constrained \bf (b) pin down the low-mass end of the mass-metallicity relation at z=3, and \bf (c) differentiate the kinematics of the resonantly scattered \lya\ line from other nebular lines; e.g. [OII] and [OIII]. This will allow us to \bf (d) distinguish scenarios where the \lya escape is due to special kinematics from those where the galaxies are relatively dust- free. \bf (e) We will cross-calibrate the star-formation rates derived from various emission lines. Finally, \bf (f) we will determine the velocity offset between the resonantly scattered \lya\ line and other lines. This is a critical parameter in determining how much of the blue wing of the \lya line is absorbed by intergalactic gas. By establishing this quantity directly, we will lay a firm foundation for tests of reionization based on \lya galaxy statistics at z > 6.


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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