Publication date: Apr 2012
Abstract:
We test precision of the Cosmological Paczynski-Wiita (CPW) potential
reflecting properties of the Schwarzschild-de Sitter (SdS) spacetimes in
modeling dynamical phenomena related to galaxy motion. We consider a
simplified model of Magellanic Clouds moving in the field of Milky Way
as test particles. Time evolution of their position along trajectories
obtained in the CPW framework using the notion of Newtonian time is
compared to the one obtained in the fully general relativistic (GR)
approach when the time evolution is expressed in terms of time related
to the location of Earth in the Galaxy field. The differences in the
position-evolution of the Magellanic Clouds obtained in the CPW and GR
approaches are given for appropriately chosen values of the Milky Way
mass. It is shown that the integrated relativistic corrections represent
10-5 part of the Newtonian CPW predictions for the orbital
characteristics of the motion and slightly grow with Galaxy mass
growing, being at least by one order higher than the local scaling GR
corrections. The integrated orbital GR corrections thus could be
important only in very precise modeling of the motion of Magellanic
Clouds. The CPW framework is used to show that, quite surprisingly, the
influence of the cosmological constant on the Magellanic Clouds motion
can be strong and significantly alters the trajectories of Magellanic
Clouds and time evolution along them. The relative contribution of the
cosmological constant is 10-1 or higher. It is most
profoundly demonstrated by the increase of the binding mass that
represents 22% for Small Magellanic Cloud and even 47% for Large
Magellanic Cloud, putting serious doubts on gravitational binding to the
Milky Way in the later case.
Authors:
Stuchlík, Zdeněk; Schee, Jan;