First direct metallicity measurement of a lensed star-forming galaxy at z=1.7
arXiv:0906.0371 · doi:10.1088/0004-637X/699/2/L161
Abstract
We present the rest-frame optical spectrum of a strongly lensed galaxy at redshift z =1.7 behind the cluster Abell 1689. We detect the temperature sensitive auroral line [O III] 4363, which allows the first direct metallicity measurement for galaxies at z > 1. Our high signal-to-noise spectrum indicates that the target is an extremely low metallicity star-forming galaxy.We estimate an intrinsic absolute B band magnitude of M_{B}=-18.3 \pm 0.1\pm1.2\times10^{8}_{\odot}$. This galaxy extends the luminosity-metallicity relation of star-forming galaxies at z > 2 by more than an order of magnitude. Given the double-nuclei like morphology and velocity profile of \ha, we tentatively suggest that it could be a merger or a proto-rotating disk galaxy.
published version in ApJ Letters. 4 pages, 4 figure, 1 table. References updated