Top panel: ELG spectra represented in the observed frame sorted by redshift. Each horizontal line corresponds to one spectrum. Vertical patterns correspond to the residuals of the sky subtraction. Diagonal patterns are the emission and absorption lines seen in the galaxy spectra. As redshift increases, the [Oii] , Hβ, [Oiii] , and Hαemission lines become redshifted. Starting at redshift 0.5, UV absorption lines enter the spectrograph window. Bottom panel: ELG spectra stacked by 50, ordered as a function of redshift represented in the rest-frame. The spectral features align vertically and are detected with higher signal-to-noise-ratio, in particular the absorption lines in the UV. Extended details about the UV absorption and emission systems are given in Zhu et al. (2015).