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arXiv · 2501.17257

Molecular Gas Heating, Star Formation Rate Relations, and AGN Feedback in Infrared-luminous Galaxy Mergers

Duncan Farrah·Andreas Efstathiou·Jose Afonso·David L Clements·Kevin Croker·Evanthia Hatziminaoglou·Maya Joyce·Vianney Lebouteiller·Alaine Lee·Carol Lonsdale·Chris Pearson·Sara Petty·Lura K Pitchford·Dimitra Rigopoulou·Aprajita Verma·Lingyu Wang
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Abstract

We examine the origin of molecular gas heating in a sample of 42 infrared-luminous galaxies at $z<0.3$ by combining two sets of archival data. First, integrated CO line luminosities in the 1-0 and 5-4 through 13-12 transitions. Second, results from radiative transfer modelling that decompose their bolometric emission into starburst, AGN, and host galaxy components. We find that the CO 1-0 and 5-4 through 9-8 lines primarily arise via radiative heating in the starburst and the host galaxy. In contrast, the CO 10-9 through 13-12 lines may arise primarily in the starburst and AGN, with an increasing contribution from mechanical heating and shocks. For the sample as a whole, we find no evidence that AGN luminosity affects the heating of molecular gas by star formation. However, for starbursts with low initial optical depths, a more luminous AGN may reduce the efficiency of starburst heating of the CO 5-4 and above lines, consistent with negative AGN feedback.

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Duncan Farrah, Andreas Efstathiou, Jose Afonso, David L Clements, Kevin Croker, Evanthia Hatziminaoglou, Maya Joyce, Vianney Lebouteiller, Alaine Lee, Carol Lonsdale, Chris Pearson, Sara Petty, Lura K Pitchford, Dimitra Rigopoulou, Aprajita Verma, Lingyu Wang. 2025-01-28. Molecular Gas Heating, Star Formation Rate Relations, and AGN Feedback in Infrared-luminous Galaxy Mergers. https://arxiv.org/abs/2501.17257

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