New Corroborative Evidence for the Overdensity of Galaxies around the Radio-Loud Quasar SDSS J0836+0054 at z = 5.8

Recently, Zheng et al. (2005) found evidence for an overdensity of galaxiesaround a radio-loud quasar, SDSS J0836+0054, at z=5.8 (a five arcmin$^2$region). We have examined our deep optical imaging data (B, V, r', i', z', andNB816) taken with the Suprime-Cam on the Subaru Telescope. The NB816narrow-band filter (lambda_c = 815 nm and $\Delta\lambda = 12$ nm) is suitablefor searching for Ly$\alpha$ emitters at $z\approx 5.7$. We have found a newstrong Ly$\alpha$ emitter at $z \approx 5.7$ close to object B identified byZheng et al. Further, the non detection of the nine objects selected by Zhenget al. (2005) in our B, V, and r' images provides supporting evidence that theyare high-z objects.Comment: 5 pages, 1 figure, accepted for PAS