Lurking systematics in predicting galaxy cold gas masses using dust luminosities and star formation rates

Steven Janowiecki, Luca Cortese, Barbara Catinella, Adelle J. Goodwin

Research output: Contribution to journalArticle


We use galaxies from the Herschel Reference Survey to evaluate commonly used indirect predictors of cold gas masses. We calibrate predictions for cold neutral atomic and molecular gas using infrared dust emission and gas depletion time methods that are self-consistent and have similar to 20 per cent accuracy (with the highest accuracy in the prediction of total cold gas mass). However, modest systematic residual dependences are found in all calibrations that depend on the partition between molecular and atomic gas, and can over/underpredict gas masses by up to 0.3 dex. As expected, dust-based estimates are best at predicting the total gas mass while depletion time-based estimates are only able to predict the (star-forming) molecular gas mass. Additionally, we advise caution when applying these predictions to high-z galaxies, as significant (0.5 dex or more) errors can arise when incorrect assumptions are made about the dominant gas phase. Any scaling relations derived using predicted gas masses may be more closely related to the calibrations used than to the actual galaxies observed.

Original languageEnglish
Pages (from-to)1390-1404
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 9 Mar 2018

Cite this