6 Suspected WR galaxies and galaxies without HeII 4686 HeII $\lambda$4686

 

6.1 Suspected WR galaxies

Candidate WR galaxies resulting from some of the searches discussed in Sect. 2 or found loosely in the literature are listed in Table 4. The reader is referred to the original papers for the justification of the possible presence of WR stars.

  

Table 3: List of suspected WR galaxies

Most of the suspected WR galaxies come from the spectrophotometric catalogue of HII galaxies of Terlevich et al. (1991), following the analysis of Masegosa et al. (1991) or Pindao et al. (1999) which also includes new objects. As stated earlier, from Masegosa et al. (1991) we take the subset of objects included in their Table 1 but not in Table 2 as candidates. Although partly based on the same observations the analysis of Masegosa et al. (1991) and Pindao et al. (1999) do not always yield the same candidates. We have retained all objects classified as "candidate'' by either one of these studies. New observations will be necessary to establish the definite presence or absence of WR features.

Few objects from Vacca & Conti (1992) have only an upper limit on broad HeII 4686 HeII $\lambda$4686. For most of them independent observations are now available. Otherwise these objects are retained as suspected WR galaxies.

In some studies of IUE spectra strong UV P-Cygni lines of N and C (N V $\lambda$1240, C IV $\lambda$1550) have been interpreted as signatures of WR stars in theses objects (e.g. Durret et al. 1985; Lamb et al. 1990). However, these lines are also strong in O stars and hence cannot be used as a clear diagnostic for WR stars (cf. Leitherer et al. 1995). Therefore, objects suspected on these grounds have not been included in Table 4.

In rare cases, WR stars have also been suspected on indirect grounds (e.g. M100: Wozniak et al. 1998).

Interestingly, a broad WR bump is suggested to be present in the optical spectrum of two distant central cluster galaxies with strong cooling flows (Abell 1068 and 1835; Allen 1995). The recent study of Contini et al. (1998), however, casts serious doubt about the reality of a broad feature in Abell 1835. If true, these objects with redshifts $z \sim$ 0.14 and 0.25 respectively, represent the most distant objects known to date where WR stars have been detected from (rest-frame) optical spectra. High redshift galaxies ($z \sim$ 3) may, however, also show WR signatures (see Sect. 7).

6.2 Emission line galaxies without He II

Conti (1991, his Table 3) lists a sample of emission line galaxies which have properties similar to WR galaxies, and where a search for HeII 4686 HeII $\lambda$4686 emission (broad or narrow) has been made with negative results. For obvious reasons such a list is necessarily incomplete and the inclusion in such a list also strongly depends on the sensitivity (S/N, resolution etc.) of the data. We therefore renounce on such a compilation. However, few updates are appropriate on some objects from Table 3 of Conti (1991).

Mrk 1087 -- While Vacca & Conti (1992) provide only an upper limit on HeII 4686 HeII $\lambda$4686, a detection is provided in the recent spectra of Vaceli et al. (1997). No information on the width of this line is given. Retained as suspected WR galaxy.

Mrk 1094 -- We have retained the criteria of Kunth & Joubert (1985) and hence included this object in Table 1. No new observations published.

0833+652 = IRAS 08339+6517 -- From their spectrum Veilleux et al. conclude that no WR features are present in this galaxy (=0833+652 in Conti 1991).

Tol 2 = Tol $\bf 0957-278$ -- Same comment as for Mrk 1094.

Tol 9 = Tol $\bf 1032-283$ -- Although no broad HeII 4686 HeII $\lambda$4686 feature seems present in this object (Kunth & Schild 1986) we list in the category of suspected WR galaxies based on the possible detection of other broad features shortward of 5876 Å (Kunth & Schild 1986).

Other objects for which an upper limit on broad WR features is given or where a non-detection is signaled are found in publications issued from the systematic searches discussed in Sect. 2.