Ratio of the luminosity of the [C II] line (L_{[C II ]}) to the FIR luminosity (L_FIR, 42.5–122.5 μm) producedby a composite stellar population, as predicted by the toy model described in the text.These values correspond to a stellar population created in a single burst from t = −100 to t = 0 Myr, and with varying amounts of residual star-formation after theburst. The red line shows the case where there is no residual star-formation, while the orange curve corresponds to a residual SFR 150 times lower than the SFR during the burst. The blue line corresponds to an exponentially declining SFR after the burst, with timescale 100 Myr . The green line shows the case of constant star-formation for reference (i.e., no end to the burst). The [C II] deficit ofHyde and its error bar are indicated with a dark gray band and shaded region in the background. Lastly, the relative decrease of L_IR with time in the case of no residual star-formation is shown with a dotted line.