The effects of a non-zero cosmological constant on the Veltmann models

TL;DR

This paper investigates how a non-zero cosmological constant influences the properties of Veltmann models, affecting observable quantities like velocity dispersion and surface density, with implications for modeling dilute collisionless systems.

Contribution

It provides a detailed analysis of the impact of a cosmological constant on Veltmann models, including modifications to key physical quantities and comparison with neighboring gravitational effects.

Findings

Cosmological constant causes non-monotonic changes in dispersion profiles.

Observable quantities are distinguishable with and without the cosmological constant.

Effects are significant in modeling dilute collisionless systems.

Abstract

The Veltmann models, which include the Plummer and Hernquist models as special cases, are studied in the presence of a cosmological constant. Physically relevant quantities such as the velocity dispersion profiles and the anisotropy parameter are computed through the use of the self-consistent approach. The cutoff radii for these models and the mass contained within this volume are also calculated. It is shown that the inclusion of a cosmological constant leads to many observable quantities such as the surface density, dispersion profiles and the anisotropy parameter becoming increasingly modified. In some scenarios, they are easily distinguished from the case where the cosmological constant is absent, as a result of their non-monotonic behaviour. The effects of neighbouring gravitational systems on the central system are also studied, and compared against the effects arising from the cosmological constant. Consequently, it is suggested that the effects of a cosmological constant can prove to be quite important when modelling dilute collisionless systems.