| Abstract | Neutral hydrogen (H I) Observations with the Arecibo 305 m telescope were made of 62 galaxies in the directions of the poor clusters, MKW 7, MKW 9, AWM 1, and AWM 3. For two systems (MKW 7, AWM 1), our H I observations are nearly complete for galaxies brighter than 15.7 mag within 1/2^deg^ of the D or cD galaxy. For MKW 9, the H I observations are nearly complete for galaxies brighter than 15.7 mag within 1^deg^ of the D galaxy. The integrated H I profile was detected for 30 of these galaxies and sensitive upper limits to the H I flux density were measured for the other 32. Twenty-two of the redshifts reported here are new measurements. We find that the average hydrogen mass-to-light ratio is 0.20 solar units with a standard deviation of 0.12 for the eighteen galaxies nearest the dominant member. This average ratio is lower and the dispersion about this mean value is smaller than what is typical for late-type spirals which are isolated or found in loose groups. A histogram of hydrogen mass-to-light ratios of the galaxies nearest the dominant member indicates that their gas properties are more similar to those of late-type galaxies near the centers of Abell clusters. Examination of a sample of 16 MKW-AWM clusters reveals a weak correlation between galaxy size and distance from the D or cD galaxy. As the projected separations from the dominant galaxy increase, the sizes of the galaxies tend to increase. The interpretation of this correlation is unclear. If the dominant galaxies define the local density maxima in poor clusters, then the correlation we observed could be one between galaxy size and surface density or it could result from the direct tidal interaction of the larger members with the dominant galaxy at the center. |
