VALES I: the molecular gas content in star-forming dusty H-ATLAS galaxies up to z = 0.35

Villanueva, V.; Ibar, E.; Hughes, T.M.; Lara-Lopez, M.A.; Dunne, L.; Eales, S.; Ivison, R.J.; Aravena, M.; Baes, M.; Bourne, N.; Cassata, P.; Cooray, A.; Dannerbauer, H.; Davies, L.J.M.; Driver, S.P.; Dye, S.; Furlanetto, C.; Herrera-Camus, R.; Maddox, S.J.; Micha?owski, M.J.; Molina, J.; Riechers, D.; Sansom, A.E.; Smith, M.W.L.; Rodighiero, G.; Valiante, E.; van der Werf, P.

Abstract

We present an extragalactic survey using observations from the Atacama Large Millimeter/submillimeter Array (ALMA) to characterize galaxy populations up to z = 0.35: the Valpara´ıso ALMA Line Emission Survey (VALES). We use ALMA Band-3 CO(1–0) observations to study the molecular gas content in a sample of 67 dusty normal star-forming galaxies selected from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). We have spectrally detected 49 galaxies at >5σ significance and 12 others are seen at low significance in stacked spectra. CO luminosities are in the range of (0.03–1.31) × 1010 K km s−1 pc2, equivalent to log(Mgas/M) = 8.9–10.9 assuming an αCO = 4.6 (K km s−1 pc2) −1, which perfectly complements the parameter space previously explored with local and high-z normal galaxies. We compute the optical to CO size ratio for 21 galaxies resolved by ALMA at ∼3.5 arcsec resolution (6.5 kpc), finding that the molecular gas is on average ∼ 0.6 times more compact than the stellar component. We obtain a global Schmidt–Kennicutt relation, given by log[[ΣSFR/(M yr−1 kpc−2)] = (1.26 ± 0.02) × log[ΣMH2 /(M pc−2)] − (3.6 ± 0.2). We find a significant fraction of galaxies lying at ‘intermediate efficiencies’ between a longstanding mode of star formation activity and a starburst, specially at LIR = 1011–12 L. Combining our observations with data taken from the literature, we propose that star formation efficiencies can be parametrized by log [SFR/MH2 ] = 0.19 × (log LIR − 11.45) − 8.26 − 0.41 × arctan[−4.84 (logLIR − 11.45)]. Within the redshift range we explore (z < 0.35), we identify a rapid increase of the gas content as a function of redshift.

Citation

Villanueva, V., Ibar, E., Hughes, T., Lara-Lopez, M., Dunne, L., Eales, S., …van der Werf, P. (2017). VALES I: the molecular gas content in star-forming dusty H-ATLAS galaxies up to z = 0.35. Monthly Notices of the Royal Astronomical Society, 470(4), 3775-3805. https://doi.org/10.1093/mnras/stx1338

• Journal Article Type: Article
• Acceptance Date: May 26, 2017
• Publication Date: May 31, 2017
• Deposit Date: Aug 25, 2017
• Publicly Available Date: Aug 25, 2017
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 470
• Issue: 4
• Pages: 3775-3805
• DOI: https://doi.org/10.1093/mnras/stx1338
• Keywords: ISM: lines and bands, galaxies: high-redshift, galaxies: ISM, infrared: galaxies, submillimetre: galaxies
• Public URL: https://nottingham-repository.worktribe.com/output/863987
• Publisher URL: https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stx1338
• Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.