Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1779538 | New Astronomy | 2006 | 8 Pages |
Abstract
We present a simple method to constrain the total mass of groups of galaxies. Tidal theory predicts that a limit to the mass of bound groups of galaxies can be obtained by using the fact that the tidal forces due to the external mass distributions are insufficient to disrupt the groups. To illustrate how the method works, we find tidal limits on the mass of 11 nearby galaxy groups. In most cases, tidal limits placed on these groups show that the mass estimations obtained from methods based either on the application of the virial theorem or moments of the projected mass are underestimated by a factor of â¼2 even if, in many cases, errors are large. Three groups show virial parameters fully concordant with the tidal constraints while two outlier groups show anomalous results. The “irregular” state of the latter suggests that the reliability of the method depends on the physical properties of the test groups, which should match the fundamental assumptions of spherical symmetry and dynamical equilibrium state.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Astronomy and Astrophysics
Authors
Giovanni C. Baiesi Pillastrini,