*4.1. Individual WR Populations*

WR stars have been found in a number of more distant galaxies. NGC 300 is a spiral galaxy in the Sculptor Group (1.9 Mpc) [95], the nearest galaxy group outside the Local Group. Broad WR features were found in the spectra of several of NGC300s H II regions in the 1980s [57,96]. Eighteen individual WRs were subsequently identified in the early 1990s by interference imaging and follow-up spectroscopy by Testor, Schild, and Breysacher [97–99], with a nineteenth one discovered by accident by Fabio Bresolin and collaborators [100]. A concerted survey with the 8-meter VLT by Schild and collaborators brought this total up to 60, a value which they state is close to complete [101]. Subsequently, an additional nine WRs were found by Crowther and collaborators [102], bringing the total to 69.

How complete do we expect such surveys to be? The distance to NGC 300 is 2.4× larger than the distance to M33, and, with similar reddenings, WR stars will be nearly 6× fainter; crowding will be also be 2.4× larger. Thus, given what was involved in obtaining a (nearly) complete sample of WRs in M33 by Neugent et al. using imaging on a 4-m telescope, one may question how well completeness can be achieved by a telescope only twice as large in aperture. M33 has 206 WRs. What would we expect the population to be scaling by the integrated H*α* luminosities? The integrated H*α* luminosity is considered to be one of the "gold standards" of recent star formation activity, and (corrected for reddening and distance) is about 2.1× greater in M33 than in NGC300 [103]. Thus, one would naively expect NGC300s WR population to number about 100.

The most interesting discovery to come out of the NGC 300 studies was Crowther et al.'s discovery that one of the WR stars is coincident with a bright, hard X-ray source [102]. Prior to this, only the Milky Way's Cyg X-3 and IC10-X1 were known as a WR+compact companion (neutron star or black hole) system; see, e.g., discussion and references in [102]. Analysis by Crowther and his team led to a mass of 37 *M* for the WR star, and >10 *M* for the compact companion, placing it firmly in the black hole camp.

Other surveys have been carried out for WR stars in even more distant systems with the 8-m VLT by Hadfield, Bibby and Crowther: IC 4662 (2.3 Mpc) [104], NGC 7793 (3.4 Mpc) [105], NGC 1313 (4.1 Mpc) [106], M83 (4.5 Mpc) [107], NGC 5068 (5–7 Mpc) [108], NGC 6744 (7–11 Mpc) [109]. Most interesting, perhaps, has been their *HST* study of M101, a large spiral located at a (relatively speaking) modest 6.7 Mpc distance [110,111], with followup spectroscopy with the Gemini 8-m [112]. To these, we note the more recent study of the WR content of NGC 625 (3.9 Mpc) [113] by integral field spectroscopy on the VLT by Ana Monreal-Ibero and collaborators.

Although these systems are all too far for completeness to be reached to determine the WC/WN ratio reliability, or provide other diagnostics for testing evolutionary models, they are potentially very useful were one of these stars to become a Type Ibc supernova sometime in the near future [114–116]. Thus, patience may be required to achieve the scientific benefits of these studies of more distant systems. It is also worth noting that no supernova progenitor has ye<sup>t</sup> to be identified as a WR star [117,118].
