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High molecular gas content and star formation rates in local galaxies that host quasars, outflows, and jets

Lookup NU author(s): Dr Christopher HarrisonORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2020 The Author. Published by Oxford University Press on behalf of The Royal Astronomical Society. We use a sample of powerful z ≈ 0.1 type 2 quasars ('obscured'; log [LAGN/erg s-1] ≳ 45), which host kpc-scale ionized outflows and jets, to identify possible signatures of AGN feedback on the total molecular gas reservoirs of their host galaxies. Specifically, we present Atacama Pathfinder EXperiment (APEX) observations of the CO(2-1) transition for nine sources and the CO(6-5) for a subset of three. We find that the majority of our sample reside in starburst galaxies (average specific star formation rates-sSFR-of 1.7 Gyr-1), with the seven CO-detected quasars also having large molecular gas reservoirs (average Mgas = 1.3 × 1010 M⊙), even though we had no pre-selection on the star formation or molecular gas properties. Despite the presence of quasars and outflows, we find that the molecular gas fractions (Mgas/M* = 0.1-1.2) and depletion times (Mgas/SFR = 0.16-0.95 Gyr) are consistent with those expected for the overall galaxy population with matched stellar masses and sSFRs. Furthermore, for at least two of the three targets with the required measurements, the CO(6-5)/CO(2-1) emission-line ratios are consistent with star formation dominating the CO excitation over this range of transitions. The targets in our study represent a gas-rich phase of galaxy evolution with simultaneously high levels of star formation and nuclear activity; furthermore, the jets and outflows do not have an immediate appreciable impact on the global molecular gas reservoirs.

Publication metadata

Author(s): Jarvis ME, Harrison CM, Mainieri V, Calistro Rivera G, Jethwa P, Zhang Z-Y, Alexander DM, Circosta C, Costa T, De Breuck C, Kakkad D, Kharb P, Lansbury GB, Thomson AP

Publication type: Article

Publication status: Published

Journal: Monthly Notices of the Royal Astronomical Society

Year: 2020

Volume: 498

Issue: 2

Pages: 1560-1575

Print publication date: 01/10/2020

Online publication date: 09/09/2020

Acceptance date: 17/07/2020

Date deposited: 11/05/2022

ISSN (print): 0035-8711

ISSN (electronic): 1365-2966

Publisher: Oxford University Press


DOI: 10.1093/mnras/staa2196


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