K_s-band images (left panels) and MOSFIRE 1D and 2D K-band spectra (right panels) for COS-DR3-195616 (upper) and COS-DR1-209435 (lower). The black solid lines show the observed 1D spectra. The gray shading shows the magnitude of the error spectrum. The solid red lines show the best-fit models from FAST++ described in Section 3.3. The green circles are drawn with a 2″ diameter. Red vertical dashed lines indicate the location of prominent emission lines. The y-axis shows flux density in units of 10⁻¹⁸ erg s⁻¹ cm⁻² Å⁻¹, plotted from zero with a dash indicating one unit.