1. Gravitationally lensed galaxies at 2 < z < 3.5: direct abundance measurements of Ly α emitters.
- Author
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Christensen, Lise, Laursen, Peter, Richard, Johan, Hjorth, Jens, Milvang-Jensen, Bo, Dessauges-Zavadsky, Miroslava, Limousin, Marceau, Grillo, Claudio, and Ebeling, Harald
- Subjects
GRAVITATIONAL lenses ,GALAXIES ,SPECTRUM analysis ,OXYGEN ,ABSORPTION - Abstract
ABSTRACT Strong gravitational lensing magnifies the flux from distant galaxies, allowing us to detect emission lines that would otherwise fall below the detection threshold for medium-resolution spectroscopy. Here we present the detection of temperature-sensitive oxygen emission lines from three galaxies at 2 ≲ z ≲ 3.5, which enables us to directly determine the oxygen abundances and thereby double the number of galaxies at z > 2 for which this has been possible. The three galaxies have ∼10 per cent solar oxygen abundances in agreement with strong emission-line diagnostics. Carbon and nitrogen ratios relative to oxygen are subsolar as expected for young metal-poor galaxies. Two of the galaxies are Lyman α (Lyα) emitters with rest-frame equivalent widths of 20 and 40 Å, respectively, and their high magnification factors allow us for the first time to gain insight into the physical characteristics of high-redshift Lyα emitters. Using constraints from the physical properties of the galaxies, we accurately reproduce their line profiles with radiative transfer models. The models show a relatively small outflow in agreement with the observed small velocity offsets between nebular emission and interstellar absorption lines. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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