Related papers: Hubble flow variance and the cosmic rest frame
The Universe on scales $10-100~h^{-1}$ Mpc is dominated by a cosmic web of voids, filaments, sheets and knots of galaxy clusters. These structures participate differently in the global expansion of the Universe: from non-expanding clusters…
A spherical cosmological model with a local void on scales of $\sim 200$ Mpc and with an inhomogeneous Hubble constant was proposed in recent two papers. This model explains consistently the observed properties of the cosmic bulk flow, the…
The increasing precision in the determination of the Hubble parameter has reached a per cent level at which large-scale cosmic flows induced by inhomogeneities of the matter distribution become non-negligible. Here we use large-scale…
We investigate the angular anisotropy of the Hubble constant using the Cosmicflows-4 catalogue, with particular emphasis on three issues often treated only implicitly in the literature: the statistical formulation of the…
The observational behavior of spherically symmetric inhomogeneous cosmological models is studied, which consist of inner and outer homogeneous regions connected by a shell or an intermediate self-similar region. It is assumed that the…
Zehavi et al. (1998) have suggested that the Hubble flow within 70/h Mpc may be accelerated by the existence of a void centered on the Local Group. Its underdensity would be ~20 %, which would result in a local Hubble distortion of about…
We characterize a cosmic rest frame in which the monopole variation of the spherically averaged nonlinear Hubble expansion is most uniform, under arbitrary local Lorentz boosts of the central observer. Using the COMPOSITE sample of 4534…
In the standard (LCDM) model of cosmology the universe has emerged out of an early homogeneous and isotropic phase. Structure formation is associated with the growth of density irregularities and peculiar velocities. Our Local Group is…
Low amplitude (linear regime) cosmic density fluctuations lead to spatial variations in the locally measurable value of $H_0$ (denoted as $H_L$), $\delta_H \equiv (H_L-H_0)/H_0$, which are of order 3-6% (95% confidence interval) in a sphere…
This work investigates the impact of cosmic flows and density perturbations on Hubble constant $H_0$ measurements using nonlinear phase-space reconstructions of the Local Universe (LU). In particular, we rely on 25 constrained N-body…
The {\em bulk flow} in the Local Universe is a collective phenomenon due to the peculiar motions of matter structures, which, instead of moving in random directions, appears to follow an approximate dipole velocity flow. We apply a…
A significant tension has become manifest between the current expansion rate of our Universe measured from the cosmic microwave background by the Planck satellite and from local distance probes, which has prompted for interpretations of…
We show that the "cold" Hubble flow observed for galaxies around the Milky Way does not represent a problem in cosmology but is due to the particular geometry and dynamics of our local wall. The behavior of the perturbed Hubble flow around…
It has been observed that the locally measured Hubble parameter converges quickest to the background value and the dipole structure of the velocity field is smallest in the reference frame of the Local Group of galaxies. We study the…
Yes. In a perturbed Friedmann model, the difference of the Hubble constants measured in two rest-frames is independent of the source peculiar velocity and depends only on the relative velocity of the observers, to lowest order in velocity.…
The knowledge of the main features of the bulk flow in the Local Universe is important for a better determination of the relative motions there, an information that would contribute to a precise calculation of the Hubble-Lema\^{\i}tre law…
Recent observations of Cepheids in the Virgo cluster have bolstered the evidence that supports a Hubble constant in 70-90 km/s/Mpc range. This evidence, by and large, probes the expansion of the Universe within 100 Mpc. We investigate the…
If gamma-ray bursts originate at cosmological distances then their angular distribution should exhibit a dipole in the direction of the solar motion relative to the cosmic microwave background. This is due to the combined effects of…
The cosmological principle asserting the large-scale uniformity of the Universe is a testable assumption of the standard cosmological model. We explore the constraints on anisotropic expansion provided by measuring directional variation in…
The meaning of "linear expansion" is explained. Particularly accurate relative distances are compiled and homogenized a) for 246 SNe Ia and 35 clusters with v<30,000 km/s, and b) for relatively nearby galaxies with 176 TRGB and 30 Cepheid…