FMOS near-IR spectroscopy of Herschel-selected galaxies: star formation rates, metallicity and dust attenuation at z similar to 1

Journal article

We investigate the properties (e.g. star formation rate, dust attenuation, stellar mass and metallicity) of a sample of infrared (IR) luminous galaxies at z ~ 1 via near-IR spectroscopy with Subaru-FMOS. Our sample consists of Herschel SPIRE and Spitzer MIPS selected sources in the COSMOS field with photometric redshifts in the range of 0.7 < z phot < 1.8, which have been targeted in two pointings (0.5 deg 2) with FMOS. We find a modest success rate for emission-line detections, with candidate Hα emission lines detected for 57 of 168 SPIRE sources (34 per cent). By stacking the near-IR spectra we directly measure the mean Balmer decrement for the Hα and Hβ lines, finding a value of 〈E(B - V)〉 = 0.51 ± 0.27 for 〈LIR〉 = 1012 L ⊙ sources at 〈z〉 = 1.36. By comparing star formation rates estimated from the IR and from the dust-uncorrected Ha line we find a strong relationship between dust attenuation and star formation rate. This relation is broadly consistent with that previously seen in star-forming galaxies at z ~ 0.1. Finally, we investigate the metallicity via the N2 ratio, finding that z ~ 1 IR-selected sources are indistinguishable from the local mass-metallicity relation. We also find a strong correlation between dust attenuation and metallicity, with the most metal-rich IR sources experiencing the largest levels of dust attenuation. © 2012 The Authors, Monthly Notices of the Royal Astronomical Society.

Authors: Roseboom, I; Bunker, A; Sumiyoshi, M; Wang, L; Dalton, G

• Publication status: Published
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 426
• Issue: 3
• Pages: 1782-1792
• Publication date: 2012-11-01
• DOI: 10.1111/j.1365-2966.2012.21777.x
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: submillimetre: galaxies; galaxies: evolution