Abstract
We report rest-frame optical Keck/NIRSPEC spectroscopy of the bright lensed
galaxy RCSGA 032727-132609 at z=1.7037. From precise measurements of the
nebular lines, we infer a number of physical properties: redshift, extinction,
star formation rate, ionization parameter, electron density, electron
temperature, oxygen abundance, and N/O, Ne/O, and Ar/O abundance ratios. The
limit on O III~4363 A tightly constrains the oxygen abundance via the
"direct" or electron temperature method, for the first time in an
average-metallicity galaxy at z~2. We compare this result to several standard
"bright-line" O abundance diagnostics, thereby testing these
empirically-calibrated diagnostics in situ. Finally, we explore the positions
of lensed and unlensed galaxies in standard diagnostic diagrams, and explore
the diversity of ionization conditions and mass--metallicity ratios at z=2.
Description
[1102.2441] The Physical Conditions of a Lensed Star-forming Galaxy at z=1.7
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