Article contents
Molecular line probes of activity in galaxies
Published online by Cambridge University Press: 04 October 2008
Abstract
The use of specific tracers of the dense molecular gas phase can help to explore the feedback of activityon the interstellar medium (ISM) in galaxies. This information is a key to any quantitative assessmentof the efficiency of the star formation process in galaxies. We present the results of a survey devotedto probe the feedback of activity through the study of the excitation and chemistry of the dense moleculargas in a sample of local universe starbursts and active galactic nuclei (AGNs). Our sample includes also17 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs). From the analysis of the LIRGs/ULIRGssubsample, published in Graciá-Carpio et al. (2007), we find the first clear observational evidencethat the star formation efficiency of the dense gas, measured by the LFIR/LHCN ratio, issignificantly higher in LIRGs and ULIRGs than in normal galaxies. Mounting evidence of overabundantHCN in active environments would even reinforce the reported trend, pointing to a significant turnupward in the Kennicutt-Schmidt law around LFIR = 1011L๏. This result has majorimplications for the use of HCN as a tracer of the dense gas in local and high-redshift luminousinfrared galaxies.
- Type
- Research Article
- Information
- European Astronomical Society Publications Series , Volume 31: Far-Infrared Workshop 2007 , 2008 , pp. 85 - 88
- Copyright
- © EAS, EDP Sciences, 2008
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