On the quiescence of the Hubble flow in the vicinity  of the Local Group

Ekholm, T.; Baryshev, Yu. V.; Teerikorpi, P.; Hanski, M.; Paturel, G.

doi:10.1051/0004-6361:20010161

Cited by 56 publications

(68 citation statements)

References 13 publications

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“…The distances from the HST data also confirmed that the Hubble law works at surprisingly small scales as observed in independent studies (Sandage & Tammann 1975;Ekholm et al 2001;Karachentsev et al 2002). The Hubble diagram (velocity vs. distance) directly shows the local expansion rate H as given by these remarkable HST observations.…”

Section: Introductionsupporting

confidence: 84%

The extragalactic Cepheid bias: significant influence on the cosmic distance scale

Paturel

Teerikorpi

2005

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The unique measurements with the Hubble Space Telescope of Cepheid variable stars in nearby galaxies led to extragalactic distances that made the HST Key Project conclude that the Hubble constant is H 0 = 72 km s −1 Mpc −1 . The idea that H 0 is now known is widely spread among the astronomical community. Some time ago, we suggested that a strong selection effect may still exist in the Cepheid method, resulting in too short distances. Using a model similar to traditional bias corrections, we deduce here new estimates of distances from HST and previous ground-based observations which are both affected by this effect, showing the same trend which starts at different distances. The recent measurement of M 83 with the VLT is unbiased. Revisiting the calibration of HSTKP's with our new scale, makes long-range distance criteria more concordant and reduces the value of H 0 to ≈60 km s −1 Mpc −1 . Locally, the corrected Cepheid distances give H local = 56 km s −1 Mpc −1 and reduce the velocity dispersion in the Hubble flow. These numbers are indicative of the influence of the suggested Cepheid bias in the context of the HSTKP studies and are not final values.

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Section: Introductionsupporting

confidence: 84%

The extragalactic Cepheid bias: significant influence on the cosmic distance scale

Paturel

Teerikorpi

2005

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“…Chernin 2001Ekholm et al 2001;Baryshev et al 2001;Byrd et al 2007;Niemi et al 2007;Teerikorpi et al 2008). Study of the Local Group enables one to learn not only the mass in the system, but simultaneusly, the local density of the dark energy itself.…”

Section: Discussionmentioning

confidence: 99%

Local dark matter and dark energy as estimated on a scale of ~1 Mpc in a self-consistent way

Chernin¹,

Teerikorpi²,

Valtonen³

et al. 2009

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Context. Dark energy was first detected from large distances on gigaparsec scales. If it is vacuum energy (or Einstein's Λ), it should also exist in very local space. Here we discuss its measurement on megaparsec scales of the Local Group. Aims. We combine the modified Kahn-Woltjer method for the Milky Way-M 31 binary and the HST observations of the expansion flow around the Local Group in order to study in a self-consistent way and simultaneously the local density of dark energy and the dark matter mass contained within the Local Group. Methods. A theoretical model is used that accounts for the dynamical effects of dark energy on a scale of ∼1 Mpc. Results. The local dark energy density is put into the range 0.8−3.7ρ v (ρ v is the globally measured density), and the Local Group mass lies within 3.1−5.8 × 10 12 M . The lower limit of the local dark energy density, about 4/5× the global value, is determined by the natural binding condition for the group binary and the maximal zero-gravity radius. The near coincidence of two values measured with independent methods on scales differing by ∼1000 times is remarkable. The mass ∼4 × 10 12 M and the local dark energy density ∼ρ v are also consistent with the expansion flow close to the Local Group, within the standard cosmological model. Conclusions. One should take into account the dark energy in dynamical mass estimation methods for galaxy groups, including the virial theorem. Our analysis gives new strong evidence in favor of Einstein's idea of the universal antigravity described by the cosmological constant.

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“…He saw a mystery in the fact that the local expansion proceeds in a quite regular way. Moreover, the rate of expansion is similar, if not identical, to the global Hubble constant (Ekholm et al 2001;Thim et al 2003;Karachentsev 2005;Karachentsev et al 2002aKarachentsev et al , 2003bWhiting 2003). Originally, the Friedmann theory described the expansion of a smooth, uniform self-gravitating medium.…”

Section: The Virgocentric Flowmentioning

confidence: 98%

Dark energy domination in the Virgocentric flow

Chernin¹,

Караченцев

Nasonova

et al. 2010

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Context. The standard ΛCDM cosmological model implies that all celestial bodies are embedded in a perfectly uniform dark energy background, represented by Einstein's cosmological constant, and experience its repulsive antigravity action. Aims. Can dark energy have strong dynamical effects on small cosmic scales as well as globally? Continuing our efforts to clarify this question, we now focus on the Virgo Cluster and the flow of expansion around it. Methods. We interpret the Hubble diagram from a new database of velocities and distances of galaxies in the cluster and its environment, using a nonlinear analytical model, which incorporates the antigravity force in terms of Newtonian mechanics. The key parameter is the zero-gravity radius, the distance at which gravity and antigravity are in balance. Results. 1. The interplay between the gravity of the cluster and the antigravity of the dark energy background determines the kinematical structure of the system and controls its evolution. 2. The gravity dominates the quasi-stationary bound cluster, while the antigravity controls the Virgocentric flow, bringing order and regularity to the flow, which reaches linearity and the global Hubble rate at distances > ∼ 15 Mpc. 3. The cluster and the flow form a system similar to the Local Group and its outflow. In the velocity-distance diagram, the cluster-flow structure reproduces the group-flow structure with a scaling factor of about 10; the zero-gravity radius for the cluster system is also 10 times larger. Conclusions. The phase and dynamical similarity of the systems on the scales of 1−30 Mpc suggests that a two-component pattern may be universal for groups and clusters: a quasi-stationary bound central component and an expanding outflow around it, caused by the nonlinear gravity-antigravity interplay with the dark energy dominating in the flow component.

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On the quiescence of the Hubble flow in the vicinity of the Local Group

Cited by 56 publications

References 13 publications

The extragalactic Cepheid bias: significant influence on the cosmic distance scale

The extragalactic Cepheid bias: significant influence on the cosmic distance scale

Local dark matter and dark energy as estimated on a scale of ~1 Mpc in a self-consistent way

Dark energy domination in the Virgocentric flow

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