NOAO >   Observing Info >   Approved Programs >   2014A-0440

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Proposal Information for 2014A-0440


PI: Mark Dickinson, NOAO, med@noao.edu
Address: 950 N. Cherry Ave., Tucson, AZ 85719, USA

CoI: Jeyhan Kartaltepe, NOAO
CoI: Ben Weiner, University of Arizona
CoI: Susan Kassin, STScI
CoI: Frederic Bournaud, CEA/Saclay
CoI: Peter Eisenhardt, JPL
CoI: Hanae Inami, NOAO
CoI: Janine Pforr, NOAO

Title: Are starbursts really mergers at high redshift? A kinematic investigation

Abstract: Star-forming galaxies obey a remarkable ``main sequence'' correlation between their star formation rates (SFR) and stellar masses (M^\ast), whose normalization (the specific star formation rate, SSFR) evolves with redshift. A minority of starbursts, with much higher SSFR, are found at all redshifts, and may be an important evolutionary stage, fueling AGN activity and building bulges and spheroids. Locally, starbursting ultraluminous infrared galaxies are the product of galaxy mergers, but this is not so clear at z > 1, where ULIRGs are hundreds of times more common, but where HST images reveal only loose correlations between irregular/disturbed morphology and starburst activity. We propose to use MOSFIRE spectroscopy to measure kinematics for ~80 \em Herschel far-IR-selected galaxies at z ~ 1.5, distributed over the SFR-M^\ast plane. We will look for kinematic differences (larger \sigma_V or \sigma/V_rot at fixed M^\ast; increased line asymmetry, and a new kinematic irregularity index optimized from numerical simulations) between main sequence and starburst galaxies that would indicate a prevalence of merger activity at higher SSFR. This program was allocated 1 night in 2013B, but was scheduled so that it will be impossible to observe our fields in 3 position angles as required. We request additional time in 2014A to complete the observations as planned.


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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