Molecular gas, stars, and dust in sub-L star-forming galaxies at z ∼ 2: Evidence for universal star formation and non-universal dust-to-gas ratio

Miroslava Dessauges-Zavadsky, Michel Zamojski, Daniel Schaerer, Françoise Combes, Eiichi Egami, Panos Sklias, Mark A. Swinbank, Johan Richard, Tim Rawle

Research output: Contribution to journalArticlepeer-review

Abstract

Current star-forming galaxies (SFGs) with CO measurements at z ∼ 2 suffer from a bias toward high star formation rates (SFR) and high stellar masses (M ∗). It is yet essential to extend the CO measurements to the more numerous z ∼ 2 SFGs with L IR < L = 4× 1011 L⊙ and M ∗ < 2.5× 1010 M⊙. We have achieved CO, stars, and dust measurements in 8 such sub-L SFGs with the help of gravitational lensing. Combined with CO-detected galaxies from the literature, we find that the L IR, L′CO(1-0) data are best-fitted with a single relation that favours a universal star formation. This picture emerges because of the enlarged star formation efficiency spread of the current z>1 SFGs sample. We show that this spread is mostly triggered by the combination of redshift, specific SFR, and M ∗. Finally, we find evidence for a non-universal dust-to-gas ratio (DGR) with a clear trend for a lower DGR mean in z>1 SFGs by a factor of 2 with respect to local galaxies and high-redshift sub-mm galaxies at fixed about solar metallicity.

Original languageEnglish (US)
Pages (from-to)254-257
Number of pages4
JournalProceedings of the International Astronomical Union
Volume11
Issue numberS315
DOIs
StatePublished - Aug 1 2015
Externally publishedYes

Keywords

  • Gravitational lensing
  • galaxies: evolution
  • galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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