[O iii]/[N ii] as an abundance indicator at high redshift

Abstract

Among 'empirical' methods of estimating oxygen abundances in extragalactic H ii regions, the use of the ratio of nebular lines of [O iii] and [N ii], first introduced by Alloin et al. in 1979, is reappraised with modern calibration data and shown to have certain advantages over R 23 ≡ ([O ii] + [O iii])/Hβ and N 2 ≡ [N ii] λ6583/Hα, particularly when applied to star-forming galaxies at high redshifts.

On the universality of luminosity–metallicity and mass–metallicity relations for compact star-forming galaxies at redshifts 0 < z < 3

“…This method provides a good measure of the metallicity below about 12+logO/H 8.3 (e.g. Pilyugin 2001; Pettini & Pagel 2004;Stasińska 2005). However, at super-solar metallicities the Te-method tends to underestimate significantly the true metallicity (Stasińska 2005).…”

“…The second approach uses the empirical relations between certain combinations of strong-line intensities and metallicity, which is derived by the Te-method (e.g. Alloin et al 1979;Pagel et al 1979;Pilyugin 2001;Pettini & Pagel 2004;Pilyugin & Thuan 2005;Stasińska 2006;Pilyugin et al 2010).…”

Inefficient star formation in extremely metal poor galaxies

“…Here we report spatiallyresolved infrared observations of two galaxies with oxygen abundances below 10 per cent solar, and show that stars form very inefficiently in seven star-forming clumps of these galaxies. The star formation efficiencies are more than ten times lower than found in normal, metal rich galaxies today, suggesting that star formation may have been very inefficient in the early Universe.The two galaxies that are the focus of this study are Sextans A, a dwarf irregular at 1.4 Mpc with oxygen abundance of 7% Solar 11,12 , and ESO 146-G14, a low-surface-brightness galaxy at 22.5 Mpc with 9% solar oxygen abundance 11,13 . Their metallicities may be similar to that of gas out of which Population II stars form in the early Universe around redshift from 7 to 12 14 .…”

“…The two galaxies that are the focus of this study are Sextans A, a dwarf irregular at 1.4 Mpc with oxygen abundance of 7% Solar 11,12 , and ESO 146-G14, a low-surface-brightness galaxy at 22.5 Mpc with 9% solar oxygen abundance 11,13 . Their metallicities may be similar to that of gas out of which Population II stars form in the early Universe around redshift from 7 to 12 14 .…”

Mass and metallicity constraints on supernova progenitors derived from integral field spectroscopy of the environment

“…We performed aperture extraction to the flux-calibrated (x, y, λ) datacubes in the wavelength direction to obtain the spectra of the clusters in the field of view. We then measured the emission lines to determine metallicity using strong line method (Pettini & Pagel 2004). The age of the clusters was determined by comparison of Hα or near-infrared Ca II triplet equivalent widths with simple stellar population (SSP) models from Starburst99 (Leitherer et al 1999) for the respective metallicities.…”