  In a recent study, using the distribution of galaxies in the north galactic
pole of SDSS DR7 region enclosed in a 500$\mpch$ box, we carried out our ELUCID
simulation (Wang et al. 2016, ELUCID III). Here we {\it light} the dark matter
halos and subhalos in the reconstructed region in the simulation with galaxies
in the SDSS observations using a novel {\it neighborhood} abundance matching
method. Before we make use of thus established galaxy-subhalo connections in
the ELUCID simulation to evaluate galaxy formation models, we set out to
explore the reliability of such a link. For this purpose, we focus on the
following a few aspects of galaxies: (1) the central-subhalo luminosity and
mass relations; (2) the satellite fraction of galaxies; (3) the conditional
luminosity function (CLF) and conditional stellar mass function (CSMF) of
galaxies; and (4) the cross correlation functions between galaxies and the dark
matter particles, most of which are measured separately for all, red and blue
galaxy populations. We find that our neighborhood abundance matching method
accurately reproduces the central-subhalo relations, satellite fraction, the
CLFs and CSMFs and the biases of galaxies. These features ensure that thus
established galaxy-subhalo connections will be very useful in constraining
galaxy formation processes. And we provide some suggestions on the three levels
of using the galaxy-subhalo pairs for galaxy formation constraints. The
galaxy-subhalo links and the subhalo merger trees in the SDSS DR7 region
extracted from our ELUCID simulation are available upon request.
