of these objects are physically associated with the quasars. Of the 20 close neighbors, 11 have UV magnitudes and slopes that suggest that they are unlikely to be at $z\simeq6$. Finding these 11 foreground galaxies is consistent within $1\sigma$ of these Poisson expectations. The remaining 9 neighbors have UV magnitudes and slopes consistent with known $z\simeq6$ galaxies. We will adopt this number of 9 potential quasar companion galaxies in our discussion below, however we note that the true number of $m_J<26.5$ $z\simeq6$ companion galaxies in our images could be between 0 and 20, with 9 a more reasonable upper limit on the expected number based on the above arguments.

In Figure \[fig:overdensity\] we plot the average number of potential $z\simeq6$ companion galaxies found in our quasar fields, compared to expectations for number counts of $z=6$ galaxies in random fields [@Finkelstein2015]. We see significant excess compared to expectations of random pointings, with our average of $\sim$1.5 galaxies within 0.13 cMpc of the quasars ($3\farcs2$ at $z=6$) higher than the expected number of 0.0056 galaxies, corresponding to an overdensity of a factor of $\sim$270. This large excess is similar to the overdensity found by @Decarli2017 [see their figure 3b], who detected 4 