Fig. 9
BPT diagnostic diagram for our sample of seven candidates for HeII-emitting HII regions. Full and empty circles represent the three confirmed HeII nebulae (MA 1, BCLMP 651, HBW 673) and the four remaining objects, respectively. The solid curve, from Kauffmann et al. (2003), indicates the empirical division between objects photoionized by stellar radiation (below the solid curve) and regions that are not dominated by stellar photoionization (above the solid curve).
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