Related papers: Residual Hubble-bubble effects on supernova cosmol…
The sample variance due to our local density fluctuations in measuring our local Hubble-constant ($H_0$) can be reduced to the percentage level by choosing the Hubble-flow type Ia supernovae (SNe Ia) outside of the homogeneity scale. In…
We derive an observational constraint on a spherical inhomogeneity of the void centered at our position from the angular power spectrum of the cosmic microwave background(CMB) and local measurements of the Hubble parameter. The late time…
Many ambitious experiments have been proposed to constrain dark energy and detect its evolution. At present, observational constraints are consistent with a cosmological constant and there is no firm evidence for any evolution in the dark…
We review the increasing evidence for the cosmological relevance of the cold local Hubble flow. New observations, N-body simulations and other theoretical arguments are discussed, supporting our previous suggestion that the cosmological…
The persistent 4-6$\sigma$ difference between early- and late-time Hubble constant ($H_{0}$) measurements, known as the "Hubble tension", is a major problem in modern cosmology. We study how differences in colour ($c$), stretch ($x_{1}$),…
Inflation creates large-scale cosmological density perturbations that are characterized by an isotropic, homogeneous, and Gaussian random distribution about a locally flat background. Even in a flat universe, the spatial curvature measured…
Whereas many measurements in cosmology depend on the use of integrated distances or time, galaxies evolving passively on a time scale much longer than their age difference allow us to determine the expansion rate H(z) solely as a function…
We conduct a thorough investigation into the possibility that residing in an overdense region of the Universe may induce bias in measurements of the large-scale structure. We compute the conditional correlation function and angular power…
Fundamental physical constants need not be constant, neither spatially nor temporally. -- This seeming simple statement has profound implications for a wide range of physical processes and interactions, and can be probed through a number of…
We study the dynamical effect of relative velocities between dark matter and baryonic fluids, which remained supersonic after the epoch of recombination. The impact of this supersonic motion on the formation of cosmological structures was…
For low-redshift (z < 0.1) Type Ia supernovae (SN Ia) samples used in several cosmological analyses over the past decade, we probe for systematic bias by looking for correlations between surface brightness (SB) measurements and Hubble…
We use the deepest and most complete redshift catalog currently available (the Hubble Deep Field (HDF) North supplemented by new HDF South redshift data) to minimize residuals between photometric and spectroscopic redshift estimates. The…
The presence of inhomogeneities modifies the cosmic distances through the gravitational lensing effect, and, indirectly, must affect the main cosmological tests. Assuming that the dark energy is a smooth component, the simplest way to…
Studying galaxies at different cosmic epochs entails several observational effects that need to be taken into account to compare populations across a large time span in a consistent manner. We use a sample of 166 nearby galaxies that hosted…
The relativistic effects in cosmological observables contain critical information about the initial conditions and gravity on large scales. Compared to the matter density fluctuation, some of these relativistic contributions scale with…
In cosmography, cosmokinetics, and cosmology it is quite common to encounter physical quantities expanded as a Taylor series in the cosmological redshift z. Perhaps the most well-known exemplar of this phenomenon is the Hubble relation…
We illustrate how recently improved low-redshift cosmological measurements can tighten constraints on neutrino properties. In particular we examine the impact of the assumed cosmological model on the constraints. We first consider the new…
The values of Hubble constant H0 by direct measurements with standard distance ladder are typically larger than those obtained from the observation of cosmic microwave background and the galaxy survey with inverse distance ladder. On the…
The Hubble tension, a significant discrepancy between the Hubble constant ($H_0$) values derived from early-time (Cosmic Microwave Background and Baryon Acoustic Oscillations) and late-time (Cepheid-calibrated Type Ia Supernovae)…
Assuming that a cosmological model can describe the whole Universe history, we look for the conditions of a cosmological bounce thus in agreement with late time observations. Our approach involves casting such a theory into General…