2003/05/01 by Chip Kobulnicky, Andrew Phillips, Kobulnicky, Chip +2
Biochemistry, Genetics and Molecular Biology · Chemistry · Physics and Astronomy · #Analytical Chemistry and Chromatography #Astrophysics (astro-ph) #FOS: Physical sciences #Mass Spectrometry Techniques and Applications #Metabolomics and Mass Spectrometry Studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0305023
7 figures, 10 pages, uses AASTeX submitted to ApJ, comments welcome
arxiv created 2003/05/01 · openalex publication_date 2003/05/01 · arxiv updated 2009/12/01 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/28
We develop a prescription for estimating the interstellar medium oxygen\nabundances of distant star-forming galaxies using the ratio EWR23 formed\nfrom the equivalent widths of the [O II] 3727, [O III] 4959,5007 and Hbeta\nnebular emission lines. This EWR23 approach essentially identical to the\nwidely-used R23 method of Pagel et. al (1979). Using data from three\nspectroscopic surveys of nearby galaxies, we conclude that the emission line\nequivalent width ratios are a good substitute for emission line flux ratios in\ngalaxies with active star formation. The RMS dispersion between EWR23 and\nthe reddening-corrected R23 values is sigma(log(R23)) < 0.08 dex. This\ndispersion is comparable to the emission-line measurement uncertainties for\ndistant galaxies in many spectroscopic galaxy surveys, and is smaller than the\nuncertainties of sigma(O/H) ~ 0.15 dex inherent in strong-line metallicity\ncalibrations. Because equivalent width ratios are, to first order, insentitive\nto interstellar reddening, emission line equivalent width ratios may actually\nbe superior to flux ratios when reddening corrections are not available. The\nEWR23 method presented here is likely to be most useful for statistically\nestimating the mean metallicities for large samples of galaxies to trace their\nchemical properties as a function of redshift or environment. The approach\ndeveloped here is used in a companion paper (Kobulnicky et. al 2003) to measure\nthe metallicities of star-forming galaxies at z=0.2-0.8 in the Deep\nExtragalactic Evolutionary Probe spectroscopic survey of the Groth Strip.\n