The mass-metallicity relation at z similar to 1.4 revealed with Subaru/FMOS

Journal article

We present a stellar mass-metallicity relation at z ~ 1.4 with an unprecedentedly large sample of ~340 star-forming galaxies obtained with FibreMulti-Object Spectrograph (FMOS) on the Subaru Telescope. We observed K-band selected galaxies at 1.2 ≤ zph ≤ 1.6 in the Subaru XMM-Newton Deep Survey/Ultra Deep Survey fields with M*> 109.5M⊙, and expected F(Hα) > 5 × 10-17 erg s-1 cm-2. Among the observed ~1200 targets, 343 objects show significant Ha emission lines. The gas-phase metallicity is obtained from [N II] λ6584/Hα line ratio, after excluding possible active galactic nuclei. Due to the faintness of the [N II] λ6584 lines, we apply the stacking analysis and derive the mass-metallicity relation at z ~ 1.4. Our results are compared to past results at different redshifts in the literature. The mass-metallicity relation at z ~ 1.4 is located between those at z ~ 0.8 and z ~ 2.2; it is found that the metallicity increases with decreasing redshift from z ~ 3 to z ~ 0 at fixed stellar mass. Thanks to the large size of the sample, we can study the dependence of the mass-metallicity relation on various galaxy physical properties. The average metallicity from the stacked spectra is close to the local Fundamental Metallicity Relation (FMR) in the higher metallicity part but >0.1 dex higher in metallicity than the FMR in the lower metallicity part.We find that galaxies with larger E(B -V), B -R and R -H colours tend to show higher metallicity by ~0.05 dex at fixed stellar mass. We also find relatively clearer size dependence that objects with smaller half-light radius tend to show higher metallicity by ~0.1 dex at fixed stellar mass, especially in the low-mass part. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Authors: Yabe, K; Ohta, K; Iwamuro, F; Akiyama, M; Tamura, N

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 437
• Issue: 4
• Pages: 3647-3663
• Publication date: 2014-02-01
• DOI: 10.1093/mnras/stt2185
• EISSN: 1365-2966
• ISSN: 0035-8711
• Keywords: galaxies: abundances; galaxies: high-redshift; galaxies: evolution