  The Photometric objects Around Cosmic webs (PAC) approach developed in Xu et
al. (2022b) has the advantage of making full use of spectroscopic and deeper
photometric surveys. With the merits of PAC, the excess surface density
$\bar{n}_2w_{{\rm{p}}}$ of neighboring galaxies can be measured down to stellar
mass $10^{10.80}\,M_{\odot}$ around quasars at redshift $0.8<z_{\rm{s}}<1.0$,
with the data from the Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon
Oscillation Spectroscopic Survey (eBOSS) and the Dark Energy Spectroscopic
Instrument (DESI) Legacy Imaging Surveys. We find that $\bar{n}_2w_{{\rm{p}}}$
generally increases quite steeply with the decrease of the separation. Using
subhalo abundance matching method, we can accurately model the
$\bar{n}_2w_{{\rm{p}}}$ both on small and large scales. We show that the steep
increase of the $\bar{n}_2w_{{\rm{p}}}$ towards the quasars requires that a
large fraction $f_{\mathrm{sate}}=0.29_{-0.06}^{+0.05}$ of quasars should be
satellites in massive halos, and find that this fraction measurement is
insensitive to the assumptions of our modeling. This high satellite fraction
indicates that the subhalos have nearly the same probability to host quasars as
the halos for the same (infall) halo mass, and the large scale environment has
negligible effect on the quasar activity. We show that even with this high
satellite fraction, each massive halo on average does not host more than one
satellite quasar due to the sparsity of quasars.
