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    Influence of the cosmological constant on the motion of Magellanic Clouds in the gravitational field of Milky Way

    Zdeněk Stuchlík · Září 01, 2011 · Fyzika · 0 comments
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    Publication date: Sep 2011

    Abstract:
    Using the pseudo-Newtonian (PN) potential reflecting properties of the
    Schwarz-schild-de Sitter spacetime, we estimate the influence of the
    repulsive cosmological constant Λ ~ 1.3 ×
    10-56cm-2 implied by recent cosmological tests
    onto the motion of both Small and Large Magellanic Clouds (SMC and LMC)
    in the gravitational field of the Milky Way. Considering detailed
    modelling of the gravitational field of the Galaxy disc, bulge and cold
    dark matter halo, the trajectories of SMC and LMC constructed for the PN
    potential with the cosmological constant are confronted to those given
    for Λ = 0. In the realistic model of the extended cold dark
    matter halo its edge and related total mass are taken at typical values
    reflecting recent diversity in the total Galaxy mass estimates. In all
    cases, strong influence of the cosmological constant, on 10% level or
    higher, has been found for motion of both SMC and LMC. Inside the halo,
    the Newtonian part of the PN potential is exact enough, while outside
    the halo the PN potential can give relevant relativistic corrections.
    The role of the cosmological constant is most conspicuous when binding
    mass is estimated for the satellite galaxies. We have found a strong
    influence of cosmic repulsion on the total binding mass for both
    galaxies. For SMC there is the binding mass MSMCΛ
    = 0 = 7.07 × 1011M⨀ and
    MSMCΛ > 0 = 8.61 ×
    1011M⨀, while even much higher increase is
    found for LMC, where MLMCΛ = 0 = 1.50
    × 1012M⨀ and
    MLMCΛ > 0 = 2.21 ×
    1012M⨀, putting serious doubts on the
    possibility that the LMC is bounded by the Milky Way. However, the
    estimates of binding masses are strongly influenced by initial velocity
    of SMC and LMC; we took the values inferred for the IAU MW rotation
    velocity ~ 220 km/s. Our results indicate very important role of the
    cosmic repulsion in the motion of interacting galaxies, clearly
    demonstrated in the case of the satellite SMC and LMC galaxies moving in
    the field of Milky Way. In some cases, the effect of the cosmic
    repulsion can be even comparable to the effects of the dynamical
    friction and the Andromeda Galaxy.

    Authors:
    Stuchlík, Zdeněk; Schee, Jan;

    http://adsabs.harvard.edu/abs/2011JCAP…09..018S

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