Sketch of secular SFH of a galaxy that does not display a secondary burst event. The orange dashed line corresponds to the time from the beginning of the SFH (t = 0) to the time at which the galaxy was observed (t_obs), while the red dashed line corresponds to the peak of the secular SFH. Since the galaxy experienced no burst events, the look-back time to the peak of the secular SFH coincides with the look-back time to the latest peak of star formation .