Exploring the quasar disc–wind–jet connection with LoTSS and SDSS

ABSTRACT We investigate the relationship between disc winds, radio jets, accretion rates, and black hole masses of a sample of $\sim$100 k quasars at z$\approx$ 2. Combining spectra from the 17th data release of the Sloan Digital Sky Survey (SDSS) with radio fluxes from the 2nd data release of the Low Frequency ARray (LOFAR) Two-Meter Sky Survey (LoTSS), we statistically characterize a radio-loud and radio-quiet population using a two-component Gaussian Mixture model, and perform population matching in black hole mass and Eddington fraction. We determine how the fraction of radio-loud sources changes across this parameter space, finding that jets are most efficiently produced in quasars with either a very massive central black hole ($M_{m {BH}} \gt 10^9 \,m {M}_{\odot }$) or one that is rapidly accreting ($\lambda _{\rm {Edd}}>0.3$). We also show that there are differences in the blueshift of the $m {C}\, {\small IV}$ $\lambda$ 1549 Å line and the equivalent width of the $\rm {He}\, {\small II}$ $\lambda$1640 Å line in radio loud and radio-quiet quasars that persist even after accounting for differences in the mass and accretion rate of the central black hole. Generally, we find an anticorrelation between the inferred presence of disc winds and jets, which we suggest is mediated by differences in the quasars’ spectral energy distributions. The latter result is shown through the close coupling between tracers of wind kinematics and the ionizing flux – which holds for both radio-loud and radio-quiet sources, despite differences between their emission line properties – and is hinted at by a different Baldwin effect in the two populations.