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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…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-10 Cameron Gibelyou , Dragan Huterer

We apply our symmetry based Power tensor technique to test conformity of PLANCK Polarization maps with statistical isotropy. On a wide range of angular scales (l=40-150), our preliminary analysis detects many statistically anisotropic…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-27 Pranati K. Rath , Pramoda Kr. Samal , Srikanta Panda , Debesh D. Mishra , Pavan K. Aluri

We analyze two volume limited galaxy samples from the SDSS photometric and spectroscopic data to test the isotropy in the local Universe. We use information entropy to quantify the global anisotropy in the galaxy distribution at different…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-12 Suman Sarkar , Biswajit Pandey , Rishi Khatri

Measurements of the cosmic microwave background (CMB) spectral $y$-distortion anisotropy offer a test for the statistical isotropy of the primordial density perturbations on $0.01\lesssim k{\rm Mpc}\lesssim 1$. We compute the 1-point…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-28 Atsuhisa Ota

Large patterns could exist on the microwave sky as a result of various non-standard possibilities for the large-scale Universe -- rotation or shear, non-trivial topology, and single topological defects are specific examples. All-sky (or…

Astrophysics · Physics 2009-10-31 Emory F. Bunn , Douglas Scott

We review Maxwell's multipole vectors, and elucidate some of their mathematical properties, with emphasis on the application of this tool to the cosmic microwave background (CMB). In particular, for a completely random function on the…

Astrophysics · Physics 2009-11-13 Mark R. Dennis , Kate Land

Forthcoming cosmic microwave background experiments (CMB) will provide precise new tests of structure-formation theories. The geometry of the Universe may be determined robustly, and the classical cosmological parameters, such as the…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

Most of the analysis of the Cosmic Microwave Background relies on the assumption of statistical isotropy. However, given some recent evidence pointing against isotropy, as for instance the observed alignment of different multipoles on large…

Astrophysics · Physics 2007-11-12 A. E. Gumrukcuoglu , Carlo R. Contaldi , Marco Peloso

We introduce new symmetry-based methods to test for isotropy in cosmic microwave background radiation. Each angular multipole is factored into unique products of power eigenvectors, related multipoles and singular values that provide 2 new…

Astrophysics · Physics 2008-11-26 Pramoda Kumar Samal , Rajib Saha , Pankaj Jain , John P. Ralston

The high-significance measurement of large-scale structure signals enables testing the isotropy of the Universe. The measurement of cosmological parameters through the large-scale distribution of matter is now a mature domain. This approach…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-01 G. Hurier

The exquisitely measured maps of fluctuations in the Cosmic Microwave Background (CMB) present the possibility to test the principle of Statistical Isotropy (SI) of the Universe through systematic observable measures for non-Statistical…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-12 Dipanshu , Tarun Souradeep , Shriya Hirve

The cosmological principle, asserting large-scale homogeneity and isotropy, underpins the standard model of cosmology. Testing its validity using independent astronomical probes remains crucial for understanding the global structure of the…

High Energy Astrophysical Phenomena · Physics 2026-02-13 Debosi Mondal , Biswajit Pandey , Amit Mondal

One of the main pillars of the {\Lambda}CDM model is the Cosmological Principle, which states that our Universe is statistically isotropic and homogeneous on large scales. Here we test this hypothesis using the Astrophysical Gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-06 Lorenzo Valbusa Dall'Armi , Angelo Ricciardone , Daniele Bertacca

The measurements of CMB anisotropy have opened up a window for probing the global topology of the universe on length scales comparable to and beyond the Hubble radius. We have developed a new method for calculating the CMB anisotropy in…

Astrophysics · Physics 2007-05-23 Tarun Souradeep , Dmitry Pogosyan , J. Richard Bond

Much attention has been given to the problem of estimating cosmological parameters from the $C_l$ measured by future experiments. Many of the approaches which are being used either invoke poorly controlled approximations or are…

Astrophysics · Physics 2007-05-23 Benjamin D. Wandelt , Eric Hivon , Krzysztof M. Gorski

Sparse inpainting techniques are gaining in popularity as a tool for cosmological data analysis, in particular for handling data which present masked regions and missing observations. We investigate here the relationship between sparse…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-03 Stephen M. Feeney , Domenico Marinucci , Jason D. McEwen , Hiranya V. Peiris , Benjamin D. Wandelt , Valentina Cammarota

Large-scale structure surveys can be used to measure the dipole in the cosmic microwave background (CMB), in the luminosity distances inferred from type-Ia supernova observations, and in the spatial distribution of galaxies and quasars. The…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-08 Jaiyul Yoo , Matteo Magi , Dragan Huterer

We have studied the cosmic microwave background (CMB) map looking for features beyond cosmological isotropy. We began by tiling the CMB variance map (which are produced by different smoothing scales) with stripes of different sizes along…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-12 MohammadHossein Jamshidi , Abdolali Banihashemi , Nima Khosravi

Extracting information from cosmic surveys is often done in a two-step process, construction of maps and then summary statistics such as two-point functions. We use simulations to demonstrate the advantages of a general Bayesian framework…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-06 Alan Junzhe Zhou , Scott Dodelson

Recently a symmetry-based method to test for statistical isotropy of the cosmic microwave background was developed. We apply the method to template-cleaned 3-year and 5-year WMAP-$DA$ maps. We examine a wide range of angular multipoles from…

Astrophysics · Physics 2010-11-02 Pramoda Kumar Samal , Rajib Saha , Pankaj Jain , John P. Ralston