AGN diagnostic diagram developed by Lamareille et al. (2004) and improved by Lamareille (2010).
The main dividing line is defined as (Eq. 1 of Lamareille 2010):
log([OIII]/Hb) = 0.11 / (log([OII]/Hb) - 0.92) + 0.85
where [OIII]/Hb is the line flux ratio of [OIII]5007 and Hb, but [OII]/Hb in the equivalent width (EW) ratio of [OII]3727 and Hb. The mixed regions include the 'SF/Sy2' region between the main dividing line and above this threshold:
log ([OIII]/Hb) > 0.3
and the 'composite' region between these two inequalities:
y < -(x - 1.0)**2 - 0.1x + 0.25
y > (x - 0.2)**2 - 0.6
where x = log([OII]/Hb), the same EW ratio of [OII]3727 and Hb used above.
These revised demarcations are all shown on Figure 4 of Lamareille (2010).