Discovery Sagaサイレントキーワード俯瞰

The growth of supermassive black holes and their host galaxies are intimately linked which has important implications for astrophysics in general. Specifically, we are measuring the ratio of black hole mass and stellar mass of the host galaxy over a wide range of cosmic time (0.2 < z < 1.8) using the Hubble Space Telescope (HST) and the Hyper Suprime-Cam Strategic Survey Program (HSC-SSP). The host galaxy mass is determined by decomposing the rest-frame optical images into the quasar and host galaxy components using state-of-the-art analysis tools which carefully consider the influence of the instrumental point-spread function. In FY 2019 and 2020, we reported on the final results in four key studies (Ding et al. 2020a,b; Li et al. 2021 a,b). Two of these studies present the results of the decomposition including stellar masses, and structural properties of the host galaxies including their physical sizes for over 5000 quasars (0.2 < z < 0.8) from the HSC-SSP and 32 quasars at 1 < z < 2 using HST. These measurements demonstrate that supermassive black holes and their hosts maintain a constant mass ratio out to z ~ 1.8 thus indicating a co-evolutionary scenario. Interestingly, the scatter in the relation is also similar with cosmic time which can only be understood with black hole feedback affecting their host galaxies as supported by simulations.