TY - JOUR
T1 - A candels WFC3 grism study of emission-line galaxies at z ∼ 2
T2 - A mix of nuclear activity and low-metallicity star formation
AU - Trump, Jonathan R.
AU - Weiner, Benjamin J.
AU - Scarlata, Claudia
AU - Kocevski, Dale D.
AU - Bell, Eric F.
AU - McGrath, Elizabeth J.
AU - Koo, David C.
AU - Faber, S. M.
AU - Laird, Elise S.
AU - Mozena, Mark
AU - Rangel, Cyprian
AU - Yan, Renbin
AU - Yesuf, Hassen
AU - Atek, Hakim
AU - Dickinson, Mark
AU - Donley, Jennifer L.
AU - Dunlop, James S.
AU - Ferguson, Henry C.
AU - Finkelstein, Steven L.
AU - Grogin, Norman A.
AU - Hathi, Nimish P.
AU - Juneau, Stéphanie
AU - Kartaltepe, Jeyhan S.
AU - Koekemoer, Anton M.
AU - Nandra, Kirpal
AU - Newman, Jeffrey A.
AU - Rodney, Steven A.
AU - Straughn, Amber N.
AU - Teplitz, Harry I.
PY - 2011/12/20
Y1 - 2011/12/20
N2 - We present Hubble Space Telescope Wide Field Camera 3 (WFC3) slitless grism spectroscopy of 28 emission-line galaxies at z 2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The high sensitivity of these grism observations, with >1σ detections of emission lines to f > 2.5 × 10-18ergs-1cm -2, means that the galaxies in the sample are typically 7 times less massive (median M * = 109.5 M than previously studied z 2 emission-line galaxies. Despite their lower mass, the galaxies have [O III]/Hβ ratios which are very similar to previously studied z 2 galaxies and much higher than the typical emission-line ratios of local galaxies. The WFC3 grism allows for unique studies of spatial gradients in emission lines, and we stack the two-dimensional spectra of the galaxies for this purpose. In the stacked data the [O III] emission line is more spatially concentrated than the Hβ emission line with 98.1% confidence. We additionally stack the X-ray data (all sources are individually undetected), and find that the average L [O III]/L 0.5-10 keV ratio is intermediate between typical z 0 obscured active galaxies and star-forming galaxies. Together the compactness of the stacked [O III] spatial profile and the stacked X-ray data suggest that at least some of these low-mass, low-metallicity galaxies harbor weak active galactic nuclei.
AB - We present Hubble Space Telescope Wide Field Camera 3 (WFC3) slitless grism spectroscopy of 28 emission-line galaxies at z 2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The high sensitivity of these grism observations, with >1σ detections of emission lines to f > 2.5 × 10-18ergs-1cm -2, means that the galaxies in the sample are typically 7 times less massive (median M * = 109.5 M than previously studied z 2 emission-line galaxies. Despite their lower mass, the galaxies have [O III]/Hβ ratios which are very similar to previously studied z 2 galaxies and much higher than the typical emission-line ratios of local galaxies. The WFC3 grism allows for unique studies of spatial gradients in emission lines, and we stack the two-dimensional spectra of the galaxies for this purpose. In the stacked data the [O III] emission line is more spatially concentrated than the Hβ emission line with 98.1% confidence. We additionally stack the X-ray data (all sources are individually undetected), and find that the average L [O III]/L 0.5-10 keV ratio is intermediate between typical z 0 obscured active galaxies and star-forming galaxies. Together the compactness of the stacked [O III] spatial profile and the stacked X-ray data suggest that at least some of these low-mass, low-metallicity galaxies harbor weak active galactic nuclei.
KW - galaxies: abundances
KW - galaxies: active
KW - galaxies: evolution
KW - quasars: emission lines
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U2 - 10.1088/0004-637X/743/2/144
DO - 10.1088/0004-637X/743/2/144
M3 - Article
AN - SCOPUS:83455220820
SN - 0004-637X
VL - 743
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 144
ER -