Program: GN-2022A-Q-410

Black hole (BH) mass is the most fundamental parameter in understanding Active Galactic Nuclei (AGNs) physics and BH-galaxy coevolution. AGN size-luminosity relation derived from reverberation mapping (RM) studies provides an extreme powerful tool for estimating BH mass. The current RM sample suffers from limited dynamical range of luminosity, that only a few AGNs with logL5100>45.0 have been studied. In addition, highly accreting AGNs are claimed to deviate from pre-calibrated size-luminosity relation. We proposed GMOS spectroscopy to monitor a sample of uniquely selected high luminosity quasars whose expected lag in observe frame are close to 1 year. With the help of dense photometric light curves from ZTF and ATLAS, our strategy of selecting 1 year lag targets minimizes the affection of seasonal gap, and achieves a successful rate of >90% to recover their lags from simulation. In this poor weather proposal, we propose do one-epoch spectroscopic observation for 5 targets that has a big gap in their monitoring baseline. These new data will enable us to better constrain the light curves and increase the chance to recover the lag. Together with other objects in our sample, our program will provide unprecedented constraints on single epoch BH mass calibration especially for high-z quasars.