Structure of the Virgo Cluster of Galaxies.

The Astrophysical Journal Supplement Series1961Vol. 6, pp. 213–213

Citations Over Time

Abstract

A discussion of the surface distribution, morphologic , apparent magnitudes, diameters, and velocities of over 200 bright galaxies between 12h and 13h, 0 and +20% indicates the presence of several distinct clouds and groups with different populations and velocities, at different distances. In particular, the Virgo cluster itself may consist of two overlapping, but separate, clouds: (1) a concentrated cluster of elliptical and lenticular galaxies centered at C1(12h 26.5m, + 13?2) with a mean velocity <V1> +950+ 70 p.e. km and velocity dispersion 5' 550 km sec- at a distance of the order of Mpc; (2) a diffuse cloud of spirals and irregular galaxies centered at C5(12h 27.5m, +13?9) with a mean velocity <Vs> +1450 l 120 p.e. km sec-i and velocity dispersion 750 km at a distance of the order of 11-12 Mpc. The difference between the systemic velocities of theE- and Sclouds computed in various ways is from three to four times its probable error, and the velocity distributions in each cloud are widely different. The mass of either cloud derived from velocity dispersion, N * 2 X 1014 O, and the mean mass per galaxy, 2 X 10 0, are not signiflcantly reduced compared with previous estimates, and the discrepancy between galaxy masses derived from translational or rotational motions remains unaccounted for. However, the new evidence for an accumulation of groups, clouds, and clusters in the equatorial plane of the Local Supercluster and toward its center suggests that the observed velocity dispersion bears little relation to the masses of the individual subsystems.

Citations Over Time

Abstract

Related Papers