the detected emission (FWHM $\sim$ 400 km s$^{-1}$) is atypical for its mass ($\log(M_*/M_{\odot})= 9.1^{+0.05}_{-0.09}$), exhibiting a factor of 3 deviation from the Tully–Fisher relation [@miller12]. The line width, together with the red spectral energy distribution (SED) and lack of detection in X-rays, indicates either that *if* this line is [\[O[ii]{}\]]{} then this galaxy likely hosts an type-2 active galactic nucleus (AGN) or that the galaxy has strong outflows. The direct constraint on the abundance of such population is not feasible currently at this redshift and in low-mass regime.

As discussed above, it is unlikely that the detected line is an *unresolved* [\[O[ii]{}\]]{} doublet given the spectral resolution. However, since the detected line has a moderate S/N of 6.5$\sigma$, we conservatively leave this possibility open but further suggest evidence against it in Section \[sec:serendi\] and \[sec:sedfit\].

Serendipitious Line Detections at $z \sim$ 1–2 {#sec:serendi}
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In addition to the detected emission in z7\_GSD\_3811 from our targets, we identified two other emission lines in objects which serendipitiously fell in slits.

The first object (R.A. = 3:32:43.22, decl. = $-$27:47:12.9 (J2000)) shows an emission line with two peaks. Assuming that the detected line is an [\[O[ii]{}\]]{} doublet, we derived its redshift to 