Coevolution of metallicity and star formation in galaxies toz≃ 3.7 – I. A Fundamental Plane

Abstract

With the aim of understanding the coevolution of star formation rate (SFR), stellar mass (M * ), and oxygen abundance (O/H) in galaxies up to redshift z 3.7, we have compiled the largest available dataset for studying Metallicity Evolution and Galaxy Assembly (MEGA); it comprises ∼1000 galaxies with a common O/H calibration and spans almost two orders of magnitude in metallicity, a factor of ∼ 10 6 in SFR, and a factor of ∼ 10 5 in stellar mass. From a Principal Component Analysis, we find that the 3-dimensional parameter space reduces to a Fundamental Plane of Metallicity (FPZ) given by 12 + log(O/H) = −0.14 log (SFR) + 0.37 log(M * ) + 4.82. The mean O/H FPZ residuals are small (0.16 dex) and consistent with trends found in smaller galaxy samples with more limited ranges in M * , SFR, and O/H. Importantly, the FPZ is found to be approximately redshift-invariant within the uncertainties. In a companion paper, these results are interpreted with an updated version of the model presented by Dayal et al. (2013).

Galaxy metallicity scaling relations in the EAGLE simulations

“…At z ≈ 2, the simulation predicts an MZR in good agreement with Zahid et al (2014b) but other observations suggest a higher level of evolution, with the larger discrepancies towards higher M * (e.g. Hunt et al 2016). At z ≈ 3, simulations tend to produce more metal-rich galaxies than inferred by Maiolino et al (2008) and Onodera et al (2016).…”

“…1, we compare results from simulations with observational data reported by different authors: Zahid et al (2012) (median metallicities in bins of M * and standard errors on the mean), Sánchez et al (2013) (metallicities for individual galaxies), Salim et al (2014) (median metallicities and standard deviations in M * bins) and Hunt et al (2016) (medians of metallicities with the 75 per cent and 25 per cent quantile levels). For the sake of clarity, only the maximum and median errors reported by Sánchez et al (2013) are represented at the bottom right corner.…”

“…In the case of Salim et al (2014), they calculated metallicities from SDSS data by applying the strong-line technique of Mannucci et al (2010). Data from Hunt et al (2016) correspond to a compilation of different samples of galaxies at z = 0, with metallicities calculated using the PP04 N2 strong-line method. As the normalization of the observed MZRs obtained by these authors is affected by the different metallicity calibrators used, we renormalized these observational results in order to match the median Recal-L025N0752 relation at M * ≈ 10 10.5 M .…”

“…As the normalization of the observed MZRs obtained by these authors is affected by the different metallicity calibrators used, we renormalized these observational results in order to match the median Recal-L025N0752 relation at M * ≈ 10 10.5 M . We added −0.10, 0.36, −0.02 and 0.27 dex to the data reported by Zahid et al (2012), Sánchez et al (2013), Salim et al (2014) and Hunt et al (2016), respectively. In this way, we avoid normalization issues and can focus on the comparison of the shapes of the relations.…”

“…In the following, we summarize briefly the different observational data used here (for more details, the reader is referred to the corresponding papers): de los Reyes et al (2015) (medians and scatter at z ≈ 0.8), Hunt et al (2016) (medians with 75 per cent and 25 per cent quantile levels at 0.4 < z ≤ 0.7, 0.9 < z ≤ 1.8, 1.8 < z ≤ 2.8 and 2.8 < z ≤ 3.8), Ly et al (2016) (medians with the 16th and 84th percentiles at z = 0.5-1.0), Stott et al (2013) (median values and standard errors at z ≈ 0.84-1.47), Yabe et al (2014) (medians and bootstrap errors at z ≈ 1.4), Zahid et al (2014b) (fitted metallicities and observational uncertainties at z ≈ 1.6), Wuyts et al (2016) (mean values and standard errors at z ≈ 0.9 and z ≈ 2.3), Sanders et al (2015) (mean values and uncertainties at z ≈ 2.3), Cullen et al (2014) (fitted metallicities with uncertainties at z 2), Troncoso et al (2014) (individual measurements and their uncertainties at z ≈ 3.4) and Onodera et al (2016) (results from stacking analysis at z ≈ 3.3). Dotted lines in the large four panels indicate the fits to observations at different z given by Maiolino et al (2008).…”