Edinburgh Research Explorer

The ATLAS3D project - XI. Dense molecular gas properties of CO-luminous early-type galaxies

Research output: Contribution to journalArticle

  • Alison Crocker
  • Melanie Krips
  • Martin Bureau
  • Lisa M. Young
  • Timothy A. Davis
  • Estelle Bayet
  • Katherine Alatalo
  • Leo Blitz
  • Maxime Bois
  • Frédéric Bournaud
  • Michele Cappellari
  • Roger L. Davies
  • P. T. de Zeeuw
  • Pierre-Alain Duc
  • Eric Emsellem
  • Davor Krajnović
  • Harald Kuntschner
  • Pierre-Yves Lablanche
  • Richard M. McDermid
  • Raffaella Morganti
  • Thorsten Naab
  • Tom Oosterloo
  • Marc Sarzi
  • Nicholas Scott
  • Paolo Serra
  • Anne-Marie Weijmans

Related Edinburgh Organisations

Original languageEnglish
Pages (from-to)1298-1314
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - 1 Apr 2012


Surveying 18 12CO-bright galaxies from the ATLAS3D early-type galaxy sample with the Institut de Radio Astronomie Millimétrique (IRAM) 30-m telescope, we detect 13CO(1-0) and 13CO(2-1) in all 18 galaxies, HCN(1-0) in 12/18 and HCO+(1-0) in 10/18. We find that the line ratios 12CO(1-0)/13CO(1-0) and 12CO(1-0)/HCN(1-0) are clearly correlated with several galaxy properties: total stellar mass, luminosity-weighted mean stellar age, molecular-to-atomic gas ratio, dust temperature and dust morphology. We suggest that these correlations are primarily governed by the optical depth in the 12CO lines; interacting, accreting and/or starbursting early-type galaxies have more optically thin molecular gas while those with settled dust and gas discs host optically thick molecular gas. The ranges of the integrated line intensity ratios generally overlap with those of spirals, although we note some outliers in the 12CO(1-0)/13CO(1-0), 12CO(2-1)/13CO(2-1) and HCN/HCO+(1-0) ratios. In particular, three galaxies are found to have very low 12CO(1-0)/13CO(1-0) and 12CO(2-1)/13CO(2-1) ratios. Such low ratios may signal particularly stable molecular gas which creates stars less efficiently than 'normal' (i.e. below Schmidt-Kennicutt prediction), consistent with the low dust temperatures seen in these galaxies.

    Research areas

  • galaxies: elliptical and lenticular, cD, galaxies: evolution, galaxies: ISM, galaxies: kinematics and dynamics, galaxies: stellar content

ID: 11173606