James, Bethan L.Pettini, MaxChristensen, LiseAuger, Matthew W.Becker, George D.King, Lindsay J.Quider, Anna M.Shapley, Alice E.Steidel, Charles C.2014-10-062014-10-062014-03-272014-03-270035-8711http://hdl.handle.net/10735.1/4081We present X-shooter observations of CASSOWARY 20 (CSWA 20), a star-forming (SFR ~ 6 M⊙ yr⁻¹) galaxy at z = 1.433, magnified by a factor of 11.5 by the gravitational lensing produced by a massive foreground galaxy at z = 0.741. We analysed the integrated physical properties of the H II regions of CSWA 20 using temperature- and density-sensitive emission lines. We find the abundance of oxygen to be ~1/7 of solar, while carbon is ~50 times less abundant than in the Sun. The unusually low C/O ratio may be an indication of a particularly rapid time-scale of chemical enrichment. The wide wavelength coverage of X-shooter gives us access to five different methods for determining the metallicity of CSWA 20, three based on emission lines from H II regions and two on absorption features formed in the atmospheres of massive stars. All five estimates are in agreement, within the factor of ~2 uncertainty of each method. The interstellar medium (ISM) of CSWA 20 only partially covers the star-forming region as viewed from our direction; in particular, absorption lines from neutrals and first ions are exceptionally weak. We find evidence for large-scale outflows of the ISM with speeds of up 750 km s⁻¹, similar to the values measured in other high-z galaxies sustaining much higher rates of star formation.©2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical SocietyCassowariesMetallicityEmission-line galaxiesCassowary 20Gravitational lensesArticleJames, Bethan L., Max Pettini, Lise Christensen, Matthew W. Auger, et al. 2014. "Testing metallicity indicators at z ~ 1.4 with the gravitationally lensed galaxy CASSOWARY 20*." Monthly Notices of the Royal Astronomical Society 440(2): 10.1093/mnras/stu28744021794