We performed a SED fitting analysis to the observed [*HST*]{}/Advanced Camera for Surveys (ACS; *B$_{435}$, V$_{606}$, i$_{775}$, I$_{814}$, z$_{850}$*), [*HST*]{}/WFC3 (*Y$_{105}$, J$_{125}$, H$_{160}$*), and VLT/Hawk-I $K$-band photometry of z7\_GSD\_3811, using the @bruzual03 SPS models. Details on our modeling are described in @song15. In addition to the [*HST*]{} bands originally included in the SED fitting in @song15, in this work we included the $K$-band photometry from the Hawk-I UDS and GOODS Survey [@fontana14] in the official CANDELS GOODS-S catalog (version 1.1). The [*Spitzer*]{}/IRAC photometry was excluded from the modeling, because z7\_GSD\_3811 is unfortunately heavily contaminated by a nearby bright source in IRAC. Thus, we do not have constraints on whether this galaxy exhibits the 4.5 $\mu$m color excess due to the strong [\[O[iii]{}\]]{} line falling in the 4.5 $\mu$m band that some other studies have reported for spectroscopically confirmed $z \sim $ 7–8 galaxies [@finkelstein13; @oesch15; @roberts-borsani15; @zitrin15].

As discussed in Section \[sec:lowz\], the only alternative interpretation of the detected emission in z7\_GSD\_3811 is the [\[O[ii]{}\]]{} doublet. Thus, we performed the SED fitting two times with a fixed redshift, first assuming the emission is Ly$\alpha$, and then, assuming the emission is an [\[O[ii]{}\]]{} doublet at $z$([\[O[ii]{}\]]{}) = 1.83.

Figure \[fig:sed\] shows 