NOAO >   Observing Info >   Approved Programs >   2017A-0341

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Program Information for 2017A-0341


PI: Swara Ravindranath, STScI, swara@stsci.edu
Address: 3700 SAN MARTIN DRIVE, BALTIMORE, MD 21218 USA

CoI: Michael Maseda, Leiden Observatory
CoI: Mark Dickinson, NOAO
CoI: Henry Ferguson, STScI
CoI: Jason Tumlinson, STScI
CoI: Arjen van der Wel, Max Planck Institut fur Astrophysik

Title: Semi-forbidden CIII]1909 Emission in the Rest-frame UV Spectra of Extreme Emission Line Galaxies

Abstract: We propose to use the GMOS instrument on Gemini-South to obtain the rest-frame UV spectra of Extreme Emission Line Galaxies (EELGs) at 1.4<z<2.4, which are actively star-forming and have extreme optical emission line ratios indicative of low metallicities. EELGs have physical conditions similar to the z>6 lensed star-forming galaxies, and are good candidates to calibrate the rest-UV diagnostics that can be applied to sources in the reionization era. We plan to observe 33 EELGs in the CANDELS COSMOS field, with the B600 grating and total integration of 8 hours on a single mask. We will use the GMOS spectra to confirm the ubiquity of the semi-forbidden CIII](190.9nm) emission line in low-mass, low-metallicity galaxies, to establish its utility as an alternative redshift indicator when Lyman-alpha emission becomes inaccessible at z>7 due to IGM absorption. We will use the data to (1) obtain empirical relations between equivalent widths of CIII] and gas phase metallicity, (2) compare the diagnostics using CIII] and optical emission lines to the predictions from photoionization models, (3) construct composite rest-frame UV spectra of EELGs which will serve as a useful template for studies of z>7 galaxies.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2017A):  GEM-SQ/GMOSS -- 8.5hrs band 2 (GS-2017A-Q-36)


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2017A-0341

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