The Width of Halpha versus NII (WHAN) diagram (Cid Fernández et al. 2011, http://adsabs.harvard.edu/abs/2011MNRAS.413.1687C) can be used to classify galaxies as star-forming or quenched. Using only information of two emissions lines (H-alpha equivalent width and NII flux, both available in the DAP), it is very useful for classifying galaxies that cannot be classified using BPT diagrams due to absent absorption lines.
One of the main advantages of this diagram is that you can distinguish two populations within the LI(N)ER classification in BPT: galaxies hosting a weak AGN and what they refer in the paper as ''retired galaxies'' (galaxies that are not forming stars but are ionized by hot low-mass evolved stars). So the WHAN diagram allows for the identification of galaxies in which the heating of their ionised gas is the result of old stars, rather than star formation or AGN activity.
Five classes of galaxies are identified within the WHAN diagram:
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