A CRITICAL LOOK AT THE MASS-METALLICITY-STAR FORMATION RATE RELATION IN THE LOCAL UNIVERSE. I. AN IMPROVED ANALYSIS FRAMEWORK AND CONFOUNDING SYSTEMATICS
- Department of Astronomy, Indiana University, Bloomington, IN 47404 (United States)
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)
- University of the Western Cape, Bellville, Cape Town 7535 (South Africa)
- National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
- Institut d'Astrophysique de Paris, CNRS, F-75014 Paris (France)
It has been proposed that the (stellar) mass-(gas) metallicity relation of galaxies exhibits a secondary dependence on star formation rate (SFR), and that the resulting M {sub *}-Z-SFR relation may be redshift-invariant, i.e., ''fundamental''. However, conflicting results on the character of the SFR dependence, and whether it exists, have been reported. To gain insight into the origins of the conflicting results, we (1) devise a non-parametric, astrophysically motivated analysis framework based on the offset from the star-forming ({sup m}ain{sup )} sequence at a given M {sub *} (relative specific SFR); (2) apply this methodology and perform a comprehensive re-analysis of the local M {sub *}-Z-SFR relation, based on SDSS, GALEX, and WISE data; and (3) study the impact of sample selection and of using different metallicity and SFR indicators. We show that metallicity is anti-correlated with specific SFR regardless of the indicators used. We do not find that the relation is spurious due to correlations arising from biased metallicity measurements or fiber aperture effects. We emphasize that the dependence is weak/absent for massive galaxies (log M {sub *} > 10.5), and that the overall scatter in the M {sub *}-Z-SFR relation does not greatly decrease from the M {sub *}-Z relation. We find that the dependence is stronger for the highest SSFR galaxies above the star-forming sequence. This two-mode behavior can be described with a broken linear fit in 12+log(O/H) versus log (SFR/M {sub *}), at a given M {sub *}. Previous parameterizations used for comparative analysis with higher redshift samples that do not account for the more detailed behavior of the local M {sub *}-Z-SFR relation may incorrectly lead to the conclusion that those samples follow a different relationship.
- OSTI ID:
- 22364803
- Journal Information:
- Astrophysical Journal, Vol. 797, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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