| Abstract | A study of groups of galaxies in the above regions was carried out by selecting a sample extending one magnitude deeper than previous work in the area, complete down to 15 mag. We report new redshift determinations for 58 galaxies in the region and 13 other miscellaneous galaxies, based on La Silla observations. Using a total of 266 galaxies with measured redshifts in the Pavo-Indus and Grus clouds, we perform a new analysis of groupings following a well-tested algorithm. A total of 18 groups is singled out, most of them known from previous work, even though a few additional members are added. For all the groups, we have calculated dynamical parameters and M/L ratios. All groups are found to be bound aggregates, but only one group can be virialized. For the 6 most populated examples, having at least 5 members, we also calculate several mass estimators and discuss the wide range of observed M/L ratios, which extends from 9 to nearly 500 M_sun_/L_sun_. We introduce two parameters to measure the presence of either a dominant galaxy or internal subcondensations, respectively, and test whether any correlation with the M/L ratios can be detected. No clear correlations are found, though some weak tendencies appear, which need a wider database to be tested. |
