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

Abstract

Abstract Recently, Zheng et al. (2006) found evidence for an overdensity of galaxies around a radio-loud quasar, SDSS J0836$+$0054, at $z = 5.8$ (a $5 \,\mathrm{arcmin}^2$ field). We examined our deep optical imaging data ($B, V, r^\prime, i^\prime, z^\prime$, and NB816) taken with the Suprime-Cam on the Subaru Telescope. The NB816 narrow-band filter ($\lambda_{\mathrm{c}} = 815 \,\mathrm{nm}$ and $\Delta\lambda = 12 \,\mathrm{nm}$) is suitable to search for Ly$\alpha$ emitters at $z \approx 5.7$. We found a new strong Ly$\alpha$ emitter at $z \approx 5.7$ close to object B, identified by Zheng et al. (2006). Further, the non-detection of nine objects selected by Zheng et al. (2006) in our $B, V$, and $r^{\prime}$ images provides corroborative evidence to indicate that they are high-$z$ objects.