2020MNRAS.492.1991M

We present Very Large Telescope/Spectrograph for INtegral Field Observations in the Near Infrared (VLT/SINFONI) observations of 35 quasars at 2.1 < z < 3.2, the majority of which were selected from the Clusters Around Radio-Loud AGN (CARLA) survey. CARLA quasars have large C IV-based black hole masses (M_BH > 10⁹ M_☉) and powerful radio emission (P_500 MHz_ > 27.5 W Hz^–1). We estimate H α-based M_BH, finding a scatter of 0.35 dex compared to C IV. We evaluate several recipes for correcting C IV-based masses, which reduce the scatter to 0.24 dex. The radio power of the radio-loud quasars is at most weakly correlated with the interconnected quantities H αwidth, L₅₁₀₀, and M_BH, suggesting that it is governed by different physical processes. However, we do find a strong inverse correlation between C IV blueshift and radio power linked to higher Eddington ratios and L₅₁₀₀. Under standard assumptions, the black hole (BH) growth time is longer than the cosmic age for many CARLA quasars, suggesting that they must have experienced more efficient growth in the past. If these BHs were growing from seeds since the epoch of reionization, it is possible that they grew at the Eddington limit like the quasars at z ∼ 6-7, and then continued to grow at the reduced rates observed until z ∼ 2-3. Finally, we study the relation between M_BH and environment, finding a weak positive correlation between M_BH and galaxydensity measured by CARLA.