Bibcode
Urrutia, T.; Hodge, J.; Dannerbauer, H.; Davis, T. A.; Jahnke, K.; Husemann, B.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 470, Issue 2, p.1570-1586
Fecha de publicación:
9
2017
Número de citas
42
Número de citas referidas
39
Descripción
We present single-dish 12CO(1-0) and 12CO(2-1)
observations for 14 low-redshift quasi-stellar objects (QSOs). In
combination with optical integral field spectroscopy, we study how the
cold gas content relates to the star formation rate (SFR) and black hole
accretion rate. 12CO(1-0) is detected in 8 of 14 targets and
12CO(2-1) is detected in 7 out of 11 cases. The majority of
disc-dominated QSOs reveal gas fractions and depletion times matching
normal star-forming systems. Two gas-rich major mergers show clear
starburst signatures with higher than average gas fractions and shorter
depletion times. Bulge-dominated QSO hosts are mainly undetected in
12CO(1-0), which corresponds, on average, to lower gas
fractions than in disc-dominated counterparts. Their SFRs, however,
imply shorter than average depletion times and higher star formation
efficiencies. Negative QSO feedback through removal of cold gas seems to
play a negligible role in our sample. We find a trend between black hole
accretion rate and total molecular gas content for disc-dominated QSOs
when combined with literature samples. We interpret this as an upper
envelope for the nuclear activity and it is well represented by a
scaling relation between the total and circumnuclear gas reservoir
accessible for accretion. Bulge-dominated QSOs significantly differ from
that scaling relation and appear uncorrelated with the total molecular
gas content. This could be explained either by a more compact gas
reservoir, blown out of the gas envelope through outflows, or a
different interstellar medium phase composition.
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