4686 are considered to be quite rare (e.g. Garnett
et al. 1991). Although not intended as a complete inventory these
authors quote only 17 objects drawn from the studies of dwarf emission-line
galaxies by Kunth & Sargent (1983) and Campbell et al. (1986).
Many new observations revealing nebular HeII 4686 emission have since
been found, mostly in the sample of Izotov and collaborators (see Sect. 2).
In Table ![[Table 2]](../images/cross_ref_motif.gif)
we list extragalactic HII regions showing
HeII 4686 emission which is entirely attributed to nebular emission
processes.
In some cases, however, WR signatures are suspected by some authors;
see column 8 for references.
We restrict ourself to objects from the Terlevich et al. (1991)
catalogue analysed by various authors and the sample of Izotov
and collaborators, since these constitute the largest available
samples of such objects.
All except one object (Pox 105) from Kunth & Sargent (1983) showing
HeII 4686 emission was later classified as a WR galaxy (Kunth & Joubert 1985
and references in Sect. 3).
From the four emission line galaxies with narrow HeII 4686 emission listed by
Conti (1991, his Table 2) three are now classified as WR galaxies (see Table
); the presence of a broad HeII 4686 component due to WR stars
is suspected in the Seyfert 2 galaxy Pox 52 (Kunth et al. 1987).
From the 12 objects of Campbell et al. (1986) for which a measurement is available, six remain in this category, although two additional objects are suspected to show broad HeII. In the other objects from Campbell et al., WR features have been found by other investigators (see Sect. 3), in part also in re-analysis of the same observational data (e.g. Masegosa et al. 1991).
From the sample of Izotov and collaborators (including 60 objects published
up to 1998, i.e. including Izotov & Thuan 1998), 40 show nebular HeII.
However only 9 objects (listed in Table ) reveal no broad 4686
component according to these studies and the reanalysis of Guseva et al. (1998).