VALES - IV. Exploring the transition of star formation efficiencies between normal and starburst galaxies using APEX/SEPIA Band-5 and ALMA at low redshift

C. Cheng, E. Ibar, T. M. Hughes, V. Villanueva, R. Leiton, G. Orellana, A. Muñoz Arancibia, N. Lu, C. K. Xu, C. N.A. Willmer, J. Huang, T. Cao, C. Yang, Y. Q. Xue, K. Torstensson

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

In this work, we present new the Swedish-ESO PI receiver for the Atacama Pathfinder Experiment APEX/SEPIA Band-5 observations targeting the CO (J = 2-1) emission line of 24 Herschel-detected galaxies at Ζ = 0.1-0.2. Combining this sample with our recent new Valparáiso ALMA Line Emission Survey (VALES), we investigate the star formation efficiencies [SFEs=star formation rate (SFR)/MH2] of galaxies at low redshift. We find the SFE of our sample bridges the gap between normal star-forming galaxies and Ultra-Luminous Infrared Galaxies (ULIRGs), which are thought to be triggered by different star formation modes. Considering the SFE' as the SFR and the L'CO ratio, our data show a continuous and smooth increment as a function of infrared luminosity (or star formation rate) with a scatter about 0.5 dex, instead of a steep jump with a bimodal behaviour. This result is due to the use of a sample with a much larger range of sSFR/sSFRms using LIRGs, with luminosities covering the range between normal and ULIRGs. We conclude that the main parameters controlling the scatter of the SFE in star-forming galaxies are the systematic uncertainty of the αCO conversion factor, the gas fraction, and physical size.

Original languageEnglish (US)
Article numberstx3183
Pages (from-to)248-256
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume475
Issue number1
DOIs
StatePublished - Mar 21 2018

Keywords

  • Galaxies: ISM
  • Galaxies: star formation
  • Galaxies: starburst
  • Submillimetre: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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