DIRECT OXYGEN ABUNDANCES FOR LOW-LUMINOSITY LVL GALAXIES

By D. Berg, E. Skillman, A. Marble, L. van Zee, C. Engelbracht, Janice C. Lee, Robert C. Kennicutt Jr., D. Calzetti, D. Dale, Benjamin D. Johnson. 2012

197 citations recorded by the source corpus.

We present MMT spectroscopic observations of H ii regions in 42 low luminosity galaxies in the Spitzer Local Volume Legacy survey. For 31 of the 42 galaxies in our sample, we were able to measure the temperature sensitive [O iii] λ4363 line at a strength of 4σ or greater, and thus determine oxygen abundances using the “direct” method. Our results provide the first “direct” estimates of oxygen abundance for 19 of these galaxies. “Direct” oxygen abundances were compared to B-band luminosities, 4.5 μm luminosities, and stellar masses in order to characterize the luminosity–metallicity and mass–metallicity relationships at low luminosity. We present and analyze a “Combined Select” sample composed of 38 objects (drawn from a sub-set of our parent sample and the literature) with “direct” oxygen abundances and reliable distance determinations (based on the tip of the red giant branch or Cepheid variables). Consistent with previous studies, the B band and 4.5 μm luminosity–metallicity relationships for the 38 objects were found to be 12 + log(O/H) = (6.27 ± 0.21) + (− 0.11 ± 0.01)MB and 12 + log(O/H) = (6.10 ± 0.21) + (− 0.10 ± 0.01)M[4.5] with dispersions of σ = 0.15 and 0.14, respectively. The slopes of the optical and near-IR L–Z relationships have been reported to be different for galaxies with luminosities greater than that of the LMC. However, the similarity of the slopes of the optical and near-IR L–Z relationships for our sample probably reflects little influence by dust extinction in the low luminosity galaxies. For this sample, we derive a mass–metallicity relationship of 12 + log(O/H) = (5.61 ± 0.24) + (0.29 ± 0.03)log (M⋆), which agrees with previous studies; however, the dispersion (σ = 0.15) is not significantly lower than that of the L–Z relationships. Because of the low dispersions in these relationships, if an accurate distance is available, the luminosity of a low luminosity galaxy is often a better indicator of metallicity than that derived using certain “strong-line” methods, so significant departures from the L–Z relationships may indicate that caution is prudent in such cases. With these new “direct” metallicities we also revisit the 70/160 μm color metallicity relationship. Additionally, we examine N/O abundance trends with respect to oxygen abundance and B − V color. We find a positive correlation between N/O ratio and B − V color for 0.05 ≲ B − V ≲ 0.75: log (N/O) = (1.18 ± 0.9) × (B − V) + (− 1.92 ± 0.08), with a dispersion of σ = 0.14, which is in agreement with previous studies.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/66024d1dae1057a332822c54311242cdc1629187

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Citations in the corpus

Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries (2016, background): “The gas-phase oxygen abundance is known to correlate with stellar mass in starforming galaxies, a mass-metallicity (MZ) relation that extends down to M∗ ∼ 10 6 M⊙ (Berg et al. 2012) and out to z ∼ 3.5 (e.g., Maiolino et al. 2008).”
THE UNIVERSAL STELLAR MASS–STELLAR METALLICITY RELATION FOR DWARF GALAXIES (2013, methodology): “On the other hand, Berg et al. (2011, 2012) showed that the dispersion in the MZR is just 0.15 dex when the “direct” method is used to measure gas-phase abundances from auroral lines.”
THE MASS–METALLICITY RELATION WITH THE DIRECT METHOD ON STACKED SPECTRA OF SDSS GALAXIES (2012, background): “Observational studies (Vila Costas & Edmunds 1993; van Zee & Haynes 2006; Berg et al. 2012) have found clear evidence for primary and secondary nitrogen at low and high metallicity.”
PHYSICAL PROPERTIES OF EMISSION-LINE GALAXIES AT z ∼ 2 FROM NEAR-INFRARED SPECTROSCOPY WITH MAGELLAN FIRE (2014, background): “…to the measured log(N/O) values as a function of 12+log(O/H) in the literature (van Zee et al. 1998; Liang et al. 2006; van Zee & Haynes 2006; Berg et al. 2012; Andrews & Martini 2013), we find that the log(N/O) of the FIRE composite is higher by approximately 0.4 dex than the average value…”
Evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates for LIGO/Virgo binary black holes (2017, background): “…oxygen abundance is known to correlate strongly with the total stellar mass of starforming galaxies: this “mass-metallicity relation” (MZR) has been shown to extend down to low-luminosity galaxies with stellar masses ∼106 M (Berg et al. 2012) and out to a redshift of 3.5 (Maiolino et al. 2008).”
New calibrations for abundance determinations in H ii regions (2016, unknown): “O/H diagram (Edmunds & Pagel 1978; MNRAS 000, 000–000 (0000) Izotov & Thuan 1999; Henry et al 2000; Pilyugin et al. 2003, 2004; Berg et al. 2012; Annibali et al. 2015, among many others).”
THE UNIVERSAL RELATION OF GALACTIC CHEMICAL EVOLUTION: THE ORIGIN OF THE MASS–METALLICITY RELATION (2014, background): “In nearby galaxies, the MZ relation extends down to stellar masses of ∼ 106M⊙ (Lee et al. 2006; Zahid et al. 2012a; Berg et al. 2012; Andrews & Martini 2013).”