3 New catalogue of WR galaxies

 In this section we present an updated list of all "WR galaxies'' outside the Local Group. As pointed out earlier we remind the reader that the working definition for WR galaxies refers only to the detection of a broad WR feature in an integrated spectrum, irrespectively of the included area. This fact must be taken into account in subsequent interpretations. By this working definition we also include some nearby objects (e.g. NGC 300) which, although already known to harbour WR stars, were not included in the catalogue of Conti (1991). An inventory of the Galactic WR stars is found in the 7th catalogue of van der Hucht et al. (1998; cf. van der Hucht 1996). For individual WR stars and WR populations in the Local Group see e.g. the review of Massey (1996).

3.1 Selection criteria and procedure

During the last three years the literature was followed for any publication relating to possible or confirmed signatures from WR stars in extragalactic objects. At the end of july 1998 we also made a systematic search in the Astrophysics Data System (ADS) for the occurrence of "WR'', "W-R'', "Wolf-Rayet'', or "Wolf Rayet'' in all the included literature starting with 1970. The search yielded 1780 references to refereed papers, and 1061 other references, all of which were carefully inspected. In addition all publications from the IAU Symposia 67, 80, 83, 88, 99, 105, 116, 122, 143, 149, 163 were scanned. Although a complete inspection is not possible the present procedure should guarantee a fairly high degree of completeness.

For the inclusion in our list of "WR galaxies'' the criteria are 1) the presence of broad emission at 4686 Å due to HeII, or 2) a broad "WR bump'' at $\sim$ 4660 Å, or 3) other broad emission lines attributed to WR stars. The second criterion accounts for the difficulty of resolving HeII 4686 HeII $\lambda$4686 from other emission lines in medium resolution spectra (see e.g. Kunth & Joubert 1985), but may in some cases introduce objects where nebular emission lines dominate the WR bump. Implicitly both criteria 1) and 2) were adopted in the earlier compilation of Conti (1991). The third criterion allows for objects where broad carbon lines (e.g. CIII $\lambda$5696, CIV $\lambda$5808) presumably from WR stars are detected. In practice only one case (NGC 1365 for which no blue spectrum was available) falls in this category.

The presence/absence of features and their qualification (broad and/or nebular) is generally not fully objective (see Sect. 2 for more details). Furthermore in many cases the spectra are not available for inspection. We therefore follow the procedure or judgement of the authors of the original publication.

 

Table 1: List of WR galaxies (all WR populations outside Local Group). (C91) stands for objects included in Conti (1991) catalogue  

 

Table 1: continued

 

Table 1: continued

All objects resulting from this selection are listed in Table 1. Obviously most of the objects appear in various catalogues. We have chose the following labeling priority: first the Messier number, then the NGC, the Markarian, the Zwicky lists, or finally other labels (UM, Tol, SBS, etc.). Often several regions in the same object show WR features. In this case only the main object name is listed (Col. 1); information about the different regions are given in Sect. 4.

The general properties of objects, equatorial coordinates (equinox 1950, Cols. 2 and 3), morphological type (Col. 4), apparent blue magnitude (Col. 5), and heliocentric radial velocity (Col. 6) have been extracted from NED. Column 7 gives the reference of the first publication indicating the presence of broad HeII 4686 HeII $\lambda$4686. "(C91)'' indicates that this objects was already included in the compilation of Conti (1991). Column 8 gives information about the existence of nebular HeII 4686 HeII $\lambda$4686 (see footnote of the Table for the keys). The source of this information is found under the remarks on each individual object (Sect. 4). Column 9 gives the reference to the first detection of broad CIV $\lambda$5808 (exceptionally also other broad features, cf. NGC 1365).

Our current compilation (Table 1) includes 139 WR galaxies (cf. 37 WR galaxies in Conti 1991). Among them 57 objects show also broad CIV $\lambda$5808 features. In addition to the broad (stellar) HeII 4686 HeII $\lambda$4686 emission, a nebular HeII component is well established (suspected) in 44 (54) objects.

The database will be made available electronically at the CDS and through the Web. It is our intention to update the catalogue in the future by this means.