Galaxy groups in the presence of Cosmological Constant: Increasing the Masses of Groups

Abstract

The boundaries of galaxy groups and clusters are defined by the interplay between the Newtonian attractive force and the decoupling from the local expansion of the Universe. This work extends the definition of a zero radial acceleration surface (ZRAS) and the turnaround surface (TS) for a general distribution of the masses in an expanding background, governed by the cosmological constant. We apply these definitions to different galaxy groups in the local Universe, mapping these groups up to ten megaparsec distances. We discuss the dipole and the quadrupole rate for the Local Group of Galaxies and the implementations on the Hubble diagram correction and galaxy groups virialization. With these definitions, we present the surfaces showing the interplay between the local expansion vs the local Newtonian attraction for galaxy groups in the local Universe. Further, we estimate the masses of different galaxy groups and show that the inclusion of the Cosmological Constant in the analysis predicts these masses to be higher by 5-10\%. For instance the Local Group of Galaxies is estimated to be $(2.47\pm 0.08)\cdot 10^{12}{M}_{\odot }$. For the groups with enough tracers close to the TS, the contribution of the Cosmological Constant makes the masses to be even higher. The results show the importance of including the local cosmic expansion in analyzing the Cosmic Flow of the local Universe.

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References in corpus (13)

• The M31 Velocity Vector. II. Radial Orbit Towards the Milky Way and Implied Local Group Mass
• Galaxy Groups within 3500 km s${}^{-1}$
• Galaxy Groups: A 2MASS Catalog
• The Hubble flow around the Local Group
• The mass of our Milky Way
• A dynamical model of the local cosmic expansion
• Galaxy Groups
• Balancing mass and momentum in the Local Group
• Local Group timing argument and virial theorem mass estimators from cosmological simulations
• The Local Group's mass: probably no more than the sum of its parts
• Weighing Milky Way and Andromeda in an expanding $\Lambda$CDM Universe: Decreasing the Local Group mass
• Improved Lemaitre-Tolman model and the mass and turn-around radius in group of galaxies II: the role of dark energy
• Turnaround physics beyond spherical symmetry

Cited by in corpus (4)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• The frozen outskirts: a cold Hubble flow and the mass of the Local Group
• McVittie-Plummer Spacetime: Plummer Sphere Immersed in the FLRW Universe
• Line-of-Sight Velocity Projection Impact on the Local Group Mass