Quasars at z∼6 are believed to reside in massive(>1012 h−1M⊙) dark matter halos (DMHs) supported by many cosmological simulations. As a natural consequence, we can expect galaxy overdensity around these quasars. However, observational evidence of galaxy clustering around z∼ 6 quasars is far from conclusive, with some studies finding quasars in the overdense region and others finding no sign of it. One possible explanation of this unresolved issue is the photoionization effect caused by intensive quasar radiation, which suppresses the gas cooling and star formation in the vicinity of quasars. Most previous studies targeting luminous quasars (M1450<−25) have searched surrounding galaxies in regions smaller than the proximity zone. Low-luminosity quasars, whose photoionization effect is limited, are suitable targets to examine the intrinsic galaxy clustering and their environment. We propose to take HSC images with NB827 to search galaxies at z∼6.2 around four low-luminosity quasars (<−24<M1450<−22), which are ∼1−3 mag fainter than those of previous targets and almost free from photoionization effect. The aim of this observation is to quantify, for the first time, the environment of z∼6 quasars, infer their DMH mass, and verify the possible photoionization effect.
This document was translated from LATEX by HEVEA.