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 or SSFR) evolves with redshift. A minority population of starbursts with much higher SSFR are found at all redshifts, and may represent an important stage in the transformation and evolution of galaxies, fueling AGN activity and building bulges and spheroids. Locally, starbursting ultraluminous infrared galaxies are clearly the product of galaxy mergers, but this is much less clear at z > 1, where ULIRGs are hundreds of times more common than today, but where HST observations reveal only loose correlations between irregular/disturbed morphology and starburst activity. We propose to use MOSFIRE spectroscopy to measure kinematics for >80 Herschel far-IR-selected galaxies at z 1.5, distributed over the SFR-M^ast plane. We will look for kinematic differences (larger σ_V or σ/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.
- Publication:
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NOAO Proposal
- Pub Date:
- August 2013
- Bibcode:
- 2013noao.prop..529D