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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

We explore the effects of a positive cosmological constant on astrophysical and cosmological configurations described by a polytropic equation of state. We derive the conditions for equilibrium and stability of such configurations and…

Astrophysics · Physics 2008-11-26 Andres Balaguera-Antolinez , David F. Mota , Marek Nowakowski

A nontrivial topology of the spatial section of the universe is an observable, which can be probed for all locally homogeneous and isotropic universes, without any assumption on the cosmological density parameters. We discuss how one can…

Astrophysics · Physics 2008-11-26 M. J. Reboucas

We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-22 Arman Shafieloo , Eric V. Linder

In this article we propose a novel test for statistical anisotropy of the CMB. The test is based on the fact, that the Galactic foregrounds have a remarcably strong symmetry with respect to their antipodal points and with respect to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 P. Naselsky , M. Hansen , J. Kim

We present a novel test of the cosmological principle: the idea that, on sufficiently large scales, the universe should appear homogeneous and isotropic to observers comoving with the Hubble flow. This is a fundamental assumption in modern…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-19 Oliver T. Oayda , Geraint F. Lewis

We are now beginning to learn detailed information about cosmological parameters from the shapes of the matter and radiation power spectra, together with their relative normalization. As more high quality data are gathered from galaxy…

Astrophysics · Physics 2007-05-23 Douglas Scott

A cross-correlation technique of lensing tomography is presented to measure the evolution of dark energy in the universe. The variation of the weak lensing shear with redshift around massive foreground objects like bright galaxies and…

Astrophysics · Physics 2008-11-26 Bhuvnesh Jain , Andy Taylor

We derive cosmological constraints using a galaxy cluster sample selected from the 2500~deg$^2$ SPT-SZ survey. The sample spans the redshift range $0.25< z<1.75$ and contains 343 clusters with SZ detection significance $\xi>5$. The sample…

We present a detailed analysis (including redshift tomography) of the cosmic dipoles in the Keck+VLT quasar absorber and in the Union2 SnIa samples. We show that the fine structure constant cosmic dipole obtained through the Keck+VLT quasar…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Antonio Mariano , Leandros Perivolaropoulos

We apply the Gabor transform methodology proposed in (Hansen et al. 2002, 2003) to the WMAP data in order to test the statistical properties of the CMB fluctuation field and specifically to evaluate the fundamental assumption of…

Astrophysics · Physics 2009-05-29 F. K. Hansen , A. J. Banday , K. M. Gorski

Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure. In this paper we develop and test a new statistic based on anisotropies in the…

Astrophysics · Physics 2009-11-13 Will J Percival , Martin White

Cosmological observations offer unique and robust avenues for probing the fundamental nature of dark matter particles-they broadly test a range of compelling theoretical scenarios, often surpassing or complementing the reach of terrestrial…

We present the first joint analysis of catalogs of radio galaxies and quasars to determine if their sky distribution is consistent with the standard $\Lambda$CDM model of cosmology. This model is based on the cosmological principle, which…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-29 Nathan Secrest , Sebastian von Hausegger , Mohamed Rameez , Roya Mohayaee , Subir Sarkar

Refined astrometry measurements allow us to detect large-scale deviations from isotropy through real-time observations of changes in the angular separation between sources at cosmic distances. This "cosmic parallax" effect is a powerful…

Astrophysics · Physics 2009-06-16 Claudia Quercellini , Miguel Quartin , Luca Amendola

We examine the role of the large--scale anisotropy of the high--energy cosmic ray distribution in a search for the heavy decaying dark matter (DM) signal. Using recent anisotropy measurements from the extensive air shower (EAS)…

High Energy Astrophysical Phenomena · Physics 2017-11-15 O. E. Kalashev , M. Yu. Kuznetsov

In this letter, we report precise and robust observational constraints on dark matter-dark energy scattering cross section, using the latest data from cosmic microwave background (CMB) Planck temperature and polarization, baryon acoustic…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-06 Suresh Kumar , Rafael C. Nunes

Interacting dark energy models have been suggested as alternatives to the standard cosmological model, $\Lambda$CDM. We focus on a phenomenologically interesting class of dark scattering models that is characterised by pure momentum…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-08 Maria Tsedrik , Chiara Moretti , Pedro Carrilho , Federico Rizzo , Alkistis Pourtsidou

The Cosmological Principle, that the Universe is homogeneous and isotropic on sufficiently large scales, underpins the standard model of cosmology. However, a recent analysis of 1.36 million infrared-selected quasars has identified a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-08 Lawrence Dam , Geraint F. Lewis , Brendon J. Brewer

The presence of dark energy in the Universe is inferred directly from the accelerated expansion of the Universe, and indirectly, from measurements of cosmic microwave background (CMB) anisotropy. Dark energy contributes about 2/3 of the…

Astrophysics · Physics 2011-05-05 Dragan Huterer , Michael S. Turner
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