Chapman, G. N. F. | Search NASA

NASA NTRS1988

Linear clusters of galaxies - A194

New measurements for 160 redshifts and previous measurements for 108 other redshifts are presented for galaxies within 5 deg of A194. The galaxy distribution in A194 is shown to be inconsistent with a spherically symmetric King model. A mass-to-light ratio is derived using the virial theorem which is lower than the mean for the groups in the CfA redshift survey (Huchra and Geller, 1982; Geller, 1984). A nonparametric test for galaxy-cluster alignment and a Chi-squared test are used to search for alignment of galaxy major axes with the axis of A194. Evidence for neither luminosity segregation nor significant differences in the velocity or surface distributions of galaxies as a function of morphological type is found.

Chapman, G. N. F.↗

NASA NTRS1987

Linear clusters of galaxies - A999 and A1016

Redshifts have been measured for galaxies in two of the 'linear' clusters of the sample of Adams, Strom, and Strom (1980), including 44 redshifts in A999 and 40 in A1016. From the data, it is concluded that the galaxies in A999 are probably drawn from a spherically symmetric distribution, while those in A1016 probably are not. Both A999 and A1016 have mass-to-light ratios lower than typical of other clusters. The effect of anisotropy on the determination of cluster masses from the virial theorem is examined, and it is found that if the shortest axes of these clusters are close to the line of sight, the mass-to-light ratio may be underestimated by about 50 percent. No significant evidence is found for alignments of individual cluster members with the cluster axis in the convincing linear cluster A1016. There is similarly no evidence of segregation by luminosity morphological type in A1016.

Chapman, G. N. F.↗