A MODEL FOR THE DECLINING ROTATION CURVES OF CLUSTER SPIRAL GALAXIES

Authors
Citation
M. Valluri, A MODEL FOR THE DECLINING ROTATION CURVES OF CLUSTER SPIRAL GALAXIES, The Astrophysical journal, 430(1), 1994, pp. 101-106
Citations number
19
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
430
Issue
1
Year of publication
1994
Part
1
Pages
101 - 106
Database
ISI
SICI code
0004-637X(1994)430:1<101:AMFTDR>2.0.ZU;2-I
Abstract
Recent numerical studies have shown that mean tidal fields in clusters of galaxies can cause a significant increase in the planar velocity d ispersions of stars and gas clouds in the disks of spiral galaxies. Si nce the perturbations caused by cluster tidal fields are generally wea k and fairly symmetric, the stellar distributions of the perturbed gal axies would not necessarily show obvious signs of tidal disturbance. I n this paper it is shown that the increased noncircular velocities of stars can result in a symmetric decline (at large radii) of the rotati on curves of tidally perturbed spiral galaxies in clusters. This decli ne results from the well-known phenomenon of the ''asymmetric drift'' of a high velocity dispersion stellar population. This suggests that t he observations of the declining rotation curves of spiral galaxies in clusters do not necessarily imply that their dark matter halos have b een tidally truncated as is generally assumed.