Dynamics of the Shahbazian 1 group of galaxies
New spectroscopic observations of the Shahbazian 1 group of galaxieshave been obtained with the digital spectrograph at the 5 m Haletelescope. From velocity differences between galaxies in the cluster andthe virial theorem, a mass-to-light ratio, in the V band, of 111 plus orminus 15 has been derived. The internal velocity dispersions of threegalaxies in the group have been measured. They are consistent with thoseof ordinary elliptical galaxies of comparable luminosity. This newspectroscopic evidence, coupled with recent photometric work, points tothe conclusion that the group is composed of ordinary galaxies, contraryto earlier interpretations. The group is, however, extraordinary in thesense that it is about as dense as the center of the coma cluster, andthat dynamical interactions which are typical of rich clusters may havebeen important in the history of Shahbazian 1.
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