A1367 is an irregular, BM type II-III cluster (Bautz and Morgan, 1970; Carter and Metcalfe, 1980) with a moderately high spiral fraction (Bahcall, 1977c). It has a low X-ray luminosity Lx 4 × 1043h50 - 2 erg/s and a temperature Tg 3 × 107 K (Mushotzky, 1984). The X-ray emission is extended and elongated (Figure 27a); Bechtold et al. (1983) found an X-ray core radius (equation 4.7) of rx = (0.8 × 0.4)h50-1 Mpc for the semimajor and semiminor axes of the distribution. In addition, 8 point sources and 13 resolved peaks in the X-ray emission (with typical sizes of an arc minute) were observed at higher spatial resolution (Figure 27b), 11 of which were associated with cluster galaxies. These galaxies have X-ray luminosities in the range 1040-42h50 - 2 erg/s. 21 cm observations indicate that some of these galaxies also contain neutral hydrogen (Chincarini et al., 1983). A1367 is the only irregular cluster that appears to have an extended radio halo (Hanisch, 1980).
Figure 27. The X-ray surface brightness of the A1367 cluster of galaxies, observed by Bechtold et al. (1983) with the Einstein satellite. Contours of constant X-ray surface brightness are shown superimposed on the optical image of the cluster. (a) The lower resolution IPC image, showing the irregular cluster emission. (b) The higher resolution HRI image, showing many discrete sources within the cluster, many of which are associated with individual cluster galaxies.