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Deep GMOS Spectroscopy of Extremely Red Galaxies in GOODS-South: Ellipticals, Mergers and Red Spirals at 1<z<2

Nathan Roche·James Dunlop·Karina Caputi·Ross McLure·Chris Willott·David Crampton
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Abstract

We have performed a deep spectroscopic survey of extremely red galaxies on the GOODS-South field, using GMOS on Gemini South. We present here spectra and redshifts for 16 ERGs at 0.87<z<2.02, to a limit K=20.2. The ERHs are a mixture of spheroidals, mergers and spirals, with one AGN. For at least 10 of these galaxies we observe [OII] emission lines. We perform an age-dating analysis by fitting the spectra and 9-band photometry of the ERGs with models of passively evolving stellar populations combined with a younger star-forming component. The best-fitting ages for the old stellar components range from 0.6 to 4.5 Gyr, with a mean 2.1 Gyr. Masses range from 3 to 20 times 10^10 solar masses. The star-forming component typically forms a few per cent of the total mass, with dust reddening averaging E(B-V)=0.35. Its timescale tends to be short for mergers (<50 Myr) and longer (200-800 Myr) for spiral ERGs.

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Nathan Roche, James Dunlop, Karina Caputi, Ross McLure, Chris Willott, David Crampton. 2006-04-18. Deep GMOS Spectroscopy of Extremely Red Galaxies in GOODS-South: Ellipticals, Mergers and Red Spirals at 1<z<2. https://doi.org/10.1111/j.1365-2966.2006.10439.x

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