Gravitationally lensed galaxies at 2 < z < 3.5: direct abundance measurements of Ly alpha emitters
2012 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 427, no 3, 1973-1982 p.Article in journal (Refereed) Published
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 similar to 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 a (Lya) emitters with rest-frame equivalent widths of 20 and 40 angstrom, respectively, and their high magnification factors allow us for the first time to gain insight into the physical characteristics of high-redshift Lya 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.
Place, publisher, year, edition, pages
2012. Vol. 427, no 3, 1973-1982 p.
gravitational lensing: strong, galaxies: abundances, galaxies: evolution, galaxies: high-redshift
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:su:diva-84800DOI: 10.1111/j.1365-2966.2012.22007.xISI: 000311414800012OAI: oai:DiVA.org:su-84800DiVA: diva2:581553