PI: Danilo Marchesini, Tufts University, firstname.lastname@example.org
Address: Physics Department, 212 College Avenue, Medford, MA 02155, USA
CoI: Pieter van Dokkum, Yale University
CoI: Ivo Labbe, Observatories of the Carnegie Institution
CoI: Emily Dare, Tufts University
Title: Spectroscopic Confirmation of Monster Galaxies at 3<z<4 with Keck- NIRSPEC
Abstract: One of the most fundamental questions regarding galaxy formation and evolution is when and how the most massive galaxies formed. Recent studies find that the number density of the most massive galaxies evolves little from z=4 to z ~ 1.5, contrary to the predictions from galaxy formation models, with the largest disagreement at 3 < z < 4. The discovery of a large, unexpected population of extremely massive galaxies at 3 < z < 4 is supported by the 0.5 deg.^2 NEWFIRM Medium-Band Survey (NMBS), a NOAO Survey program using medium band-width filters in the NIR to obtain high-accuracy photometric redshifts. Despite the unique depth and wavelength coverage of the NMBS, the existence of these galaxies is still intensely controversial. We propose to use NIRSPEC on Keck to obtain spectroscopic redshifts for the brightest ~50% of a large, unique, and homogeneous sample of 14 very massive galaxies at 3 < z < 4 selected from the NMBS. In 2 nights, NIRSPEC will provide continuum and emission line detections in the K-band allowing us to 1) spectroscopically confirm the existence of galaxies at 3<z<4 with M_\rm star>3\times10^11 M_\odot; 2) determine their AGN fraction; and 3) quantify the emission line contamination to the photometry.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360