Dynamical models and the mass of the virgo cluster

Journal Article · Mon Dec 15 04:00:00 EST 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158520· OSTI ID:6536650

Hoffman, G L; Olson, D W; Salpeter, E E

Dynamical model calculations for a supercluster of galaxies are carried out, assuming spherical symmetry and ignoring two-body collisions. Observational data are analyzed for the dispersion of systemic galaxy velocities in and near the Virgo cluster. This velocity dispersion decreases with increasing angular distance q from the Virgo center (and is larger for spirals than for ellipticals). Allowing the possibility that the mass-to-light ratio may vary with q, the observational data are fitted against numerical models with W (the present mass density at spatial infinity divided by the closure density) ranging from 0.03 to 0.7. No choice of W can be made at present (unless one assumes a constant mass-to-light ratio, in which case W would be close to 0.4), but the derived gravitational mass of the Virgo I cluster is almost independent of W and is well determined (in good agreement with previous virial theorem estimates): The mass inside a sphere which is tangent to the q = 6/sup 0/ cone is M/sub 6degree/ = (4.0 +- 1.0) x 10/sup 14/(100 km s/sup -1/ Mpc/sup -1//H/sub 0/)M/sub sun/, and the corresponding mass-to-light ratio is 650 +- 100 M/sub sun//L/sub sun/. The derived zero-velocity surface of the supercluster is tangent to qroughly-equal27/sup 0/.

• Research Organization: Center for Radiophysics and Space Research, Cornell University
• OSTI ID: 6536650
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 242:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMOLOGICAL MODELS
COSMOLOGY
GALAXY CLUSTERS
MASS
MATHEMATICAL MODELS
VELOCITY