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تسجيل مستخدم جديدMetal Abundances of KISS Galaxies. I. Coarse Metal Abundances and the Metallicity-Luminosity Relation
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We derive metal abundance estimates for a large sample of starbursting emission-line galaxies (ELGs). Our sample is drawn from the KPNO International Spectroscopic Survey (KISS) which has discovered over 2000 ELG candidates to date. Follow-up optical spectra have been obtained for ~900 of these objects. A three step process is used to obtain metal abundances for these galaxies. We first calculate accurate nebular abundances for 12 galaxies whose spectra cover the full optical region from [OII]3726,29 to beyond [SII]6717,31 and include detection of [OIII]4363. Using secondary metallicity indicators R_23 and p_3, we calculate metallicities for an additional 59 galaxies with spectra that cover a similar wavelength range but lack [OIII]4363. The results are used to calibrate relations between metallicity and two readily observed emission-line ratios, which allow us to estimate coarse metallicities for 519 galaxies in total. The uncertainty in these latter abundance estimates is 0.16 dex. From the large, homogeneously observed sample of star-forming galaxies we identify low metallicity candidates for future study and investigate the metallicity-luminosity relation. We find a linear metallicity-luminosity relation of the following form: 12 + log(O/H) = 4.059 - 0.240 M_B, with an RMS scatter of 0.252. This result implies that the slope of the metallicity- luminosity relation is steeper than when dwarf galaxies are considered alone, and may be evidence that the relationship is not linear over the full luminosity range of the sample.
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We present high S/N spectroscopy of 15 emission-line galaxies (ELGs) cataloged in the KPNO International Spectroscopic Survey (KISS), selected for their possession of high equivalent width [O III] lines. The primary goal of this study was to attempt
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We present follow-up spectra of 39 emission-line galaxies (ELGs) from the KPNO International Spectroscopic Survey (KISS). Many targets were selected as potentially low metallicity systems based on their absolute B magnitudes and the metallicity-lumin
osity relation. The spectra, obtained with the Lick 3-m telescope, cover the full optical region from [O II]3726,29 to beyond [S IIl6717,31 and include measurement of [O IIIl4363 in twelve objects. The spectra are presented and tables of the strong line ratios are given. For twelve high signal-to-noise ratio spectra, we determine abundance ratios of oxygen, nitrogen, neon, sulfur and argon. We find these galaxies to be metal deficient with three systems approaching O/H of 1/25th solar. We compare the abundance results from the temperature-based T_e method to the results from the strong-line p_3 method of Pilyguin (2000).
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