ner_tags: O O O O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: observations for a sample of 14 luminous nearby QSO host galaxies that we interpret in conjunction with the available optical integral field observations. This data set significantly extends the sample of luminous unobscured QSOs with molecular gas mass estimates at low redshift. Our main results of this work can be summarized as follows: We detect the 12 CO(1–0) emission line in 8 of 14 targets (∼60 per cent) with a clear preference for disc-dominated and major merger systems with a detection rate of nearly 80 per cent. The integrated 12 CO(1–0) emission line matches the spatially integrated Hα line profile, indicating that both are tracing star formation regions when averaged over kpc scales. We also detect the 12 CO(2–1) emission line in 7 of 11 targets (∼60 per cent). The corresponding r 21 brightness temperature ratio is close to 1 and ranges between 0.5 and 1.3. Some of the lowest ratios may suggest that the CO emission is already sub-thermal at J = 2 in these systems. While the disc-dominated QSO host galaxies exhibit similar gas fractions and gas depletion time-scales compared to non-AGN host galaxies, we find that bulge-dominated QSO hosts have systematically smaller gas fractions but shorter gas depletion times, given their elevated SFRs. The two major mergers in our sample show high gas fractions and rather short gas depletion times as expected from simulations for strongly interacting systems. We report a positive correlation between BH accretion rate and total molecular gas mass for disc-dominated QSO host galaxies after combining our sample with literature data. We interpret this as an upper limit of BH accretion rate, given our initial selection for the most luminous QSO at the considered redshift. We can explain this trend using a simply toy model that links the circumnuclear gas surface density with the total gas mass through a simple scaling relation for discs. The BH accretion rate in bulge-dominated QSOs host galaxies is significantly higher given their molecular gas content compared to disc-dominated QSOs hosts. This may be explained either by a more compact or steeper gas surface density gradient, by removal of the outer envelope of gas through feedback or by a significantly higher gas temperature, leading to a different composition of the different phases of ISM. While we did not measure a higher CO line excitation based on the r 21 temperature brightness ratio, this needs to be investigated with more excitation-sensitive observations. Despite the relatively small sample size of this study, we can confirm that the molecular gas content and star formation efficiency, at least in disc-dominated QSO hosts and major mergers, are indistinguishable from the corresponding population of non-AGN galaxies. Negative AGN feedback that either reduces the star formation efficiency or significantly lowers the cold gas content through galactic outflows is an implausible scenario for the majority of QSO hosts studied in this work.