Related papers: Global Anisotropies of $\Omega_\Lambda$
We employ the sample of 244 gamma-ray bursts (GRBs; i.e., C244) with the Combo correlation to test cosmic anisotropy. Meanwhile, the Pantheon sample is introduced to verify whether the GRB sample can suppress the fake anisotropic signals…
In the late 1990's, observations of 93 Type Ia supernovae were analysed in the framework of the FLRW cosmology assuming these to be `standard(isable) candles'. It was thus inferred that the Hubble expansion rate is accelerating as if driven…
Recent studies have indicated that an anisotropic cosmic expansion may exist. In this paper, we use three datasets of type Ia supernovae (SNe Ia) to probe the isotropy of cosmic acceleration. For the Union2.1 dataset, the direction and…
If the Universe is endowed with cosmic anisotropy, it will have a preferred direction of expansion. Reconstructing the expansion history by Gaussian Process (GP) can be used to probe the cosmic anisotropy model-independently. In this paper,…
Recent research reveals that the Local Group is in motion towards $(l, b) = (276, 30)$ relative to the cosmic background radiation, manifesting a velocity of 600 $\frac{km}{s}$ a phenomenon recognized as the cosmic background radiation…
The Cosmological Principle, which states that the Universe is homogeneous and isotropic (when averaged on large scales), is the foundational assumption of Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmologies such as the current standard…
In this paper, we propose a new pressure parametric model of the total cosmos energy components in a spatially flat Friedmann-Robertson-Walker (FRW) universe and then reconstruct the model into quintessence and phantom scenarios,…
We test the isotropy of the expansion of the Universe by estimating the hemispherical anisotropy of supernova type Ia (SN Ia) Hubble diagrams at low redshifts (z<0.2). We compare the best fit Hubble diagrams in pairs of hemispheres and…
The first-year WMAP data, in combination with any one of a number of other cosmic probes, show that we live in a flat \Lambda-dominated CDM universe with \Omega_m ~ 0.27 and \Omega_\Lambda ~ 0.73. In this model the late-time action of the…
We examine the anisotropies in the power spectrum by the mapping of real to redshift space. Using the Zel'dovich approximation, we obtain an analytic expression for the nonlinear redshift space power spectrum in the distant observer limit.…
The cosmic radio dipole is an anisotropy in the number counts of radio sources, analogous to the dipole seen in the cosmic microwave background (CMB). Measurements of source counts of large radio surveys have shown that though the radio…
We study the large-scale anisotropic two-point correlation function using 46,760 luminous red galaxies at redshifts 0.16 -- 0.47 from the Sloan Digital Sky Survey. We measure the correlation function as a function of separations parallel…
The measured luminosity distances of Type Ia supernovae (SNe Ia) as a function of redshift have shown that the expansion of the Universe is currently accelerating, probably due to the presence of repulsive dark energy such as Einstein's…
We investigate the effect of redshift-space distortions in the power spectrum parallel and perpendicular to the observer's line of sight, P(k_par,k_perp), using the optically selected Durham/UKST Galaxy Redshift Survey. On small, non-linear…
We study the large-scale anisotropy of the Universe by measuring the dipole in the angular distribution of a flux-limited, all-sky sample of 1.36 million quasars observed by the Wide-field Infrared Survey Explorer (WISE). This sample is…
We use information entropy to analyze the anisotropy in the mock galaxy catalogues from dark matter distribution and simulated biased galaxy distributions from $\Lambda$CDM N-body simulation. We show that one can recover the linear bias…
We report cosmic microwave background (CMB) power spectrum measurements from the first 100 sq. deg. field observed by the South Pole Telescope (SPT) at 150 and 220 GHz. On angular scales where the primary CMB anisotropy is dominant, ell ~<…
We perform observational tests of statistical isotropy using data from large-scale structure surveys spanning a wide range of wavelengths. Using data from 2MASS, 2MRS, and NVSS galaxies, and BATSE gamma-ray bursts, we constrain the…
The assumption of isotropy -- that the Universe looks the same in all directions on large scales -- is fundamental to the standard cosmological model. This model forms the building blocks of essentially all of our cosmological knowledge to…
The standard cosmological model, $\Lambda$CDM, assumes isotropy on large cosmic scales. However, recent studies using galaxy cluster scaling relations have reported an apparent $H_0$ anisotropy at $5.4\sigma$ that could be attributed to…