Constraints on BH growth history from QSO clustering at z~4 with HSC wide field imaging.

Wanqiu He

Clustering analysis for QSOs/galaxies at high redshifts could help understanding the evolution of the super massive black holes in the early universe. Based on newly released Subaru/Hyper Suprime-Cam (HSC) photometric data, we select ~1,500 z~4 faint QSOs at m_{i}<24 and ~10,000 z~4 LBGs at m_{i}<24.5 in about 100 sq.deg survey region. We estimate the bias factor for the QSOs and LBGs by checking their two point angular auto- and cross-correlation functions. The preliminary results indicate that, as similar to more luminous SDSS QSOs in the same redshift range, faint HSC QSOs also have strong clustering that QSO bias factor is ~10, which suggests that the QSO host dark matter halo (DMH) is as massive as ~10^{13} solar mass. Such a weak dependence of the bias factor on QSO luminosity indicates very high QSO duty cycle within the massive DMHs in the early universe.