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It is shown that the fluctuation in the temperature of the cosmic microwave background in any direction may be evaluated as an integral involving scalar and dipole form factors, which incorporate all relevant information about acoustic…

Astrophysics · Physics 2009-11-06 Steven Weinberg

The sky distribution of cosmic rays with energies above the 'GZK cutoff' holds important clues to their origin. The AGASA data, although consistent with isotropy, shows evidence for small-angle clustering, and it has been argued that such…

Astrophysics · Physics 2011-02-16 N. Wyn Evans , Francesc Ferrer , Subir Sarkar

We revisit the classification of polarization observables of the cosmic microwave background. There exists a unified approach to the $3 \times 3$ density matrix by which intensity, linear and circular polarization are treated on an equal…

Astrophysics · Physics 2007-05-23 John P. Ralston , Pankaj Jain

I report the current status on the determinations of the baryon fractions and dynamical/lensing masses of galaxy clusters as well as the $\sigma$ - $T$ relationship, making use of all the published data in literature which include 304…

Astrophysics · Physics 2007-05-23 Xiang-Ping Wu

If the universe is finite and smaller than the distance to the surface of last scatter, then the signature of the topology of the universe is writ on the microwave background sky. Previous efforts to search for this topology have focused on…

General Relativity and Quantum Cosmology · Physics 2016-02-09 Neil J. Cornish , David N. Spergel , Glenn D. Starkman

The cosmic microwave background temperature is a cornerstone astrophysical observable. Its present value is tightly constrained, but its redshift dependence, which can now be determined until redshift $z\sim6.34$, is also an important probe…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 L. Gelo , C. J. A. P. Martins , N. Quevedo , A. M. M. Vieira

In this paper we consider clumped baryonic matter as a spherically symmetric barotropic fluid associated with a compact four-dimensional Einstein manifold with a four-radius that is determined by the fluid density. We further investigate…

General Physics · Physics 2024-04-08 Stuart Marongwe , Stuart Kauffman

Models in which a large fraction of the Galactic dark matter takes the form of cold gas clouds imply that there is thermal microwave emission from the Galactic dark halo. Such models can therefore be directly constrained by data on the…

Astrophysics · Physics 2007-05-23 Mark Walker , Michiko Ohishi , Masaki Mori

In the standard cosmological model, the temperature anisotropy of the cosmic microwave background is interpreted as variation in the gravitational potential at the point of emission, due to the emitter being embedded in a region ${\cal C}$…

Astrophysics · Physics 2007-05-23 Richard Lieu

I show that three independent methods utilizing clusters of galaxies - cluster dynamics and mass-to-light ratio, baryon fraction in clusters, and cluster evolution - all indicate the same robust result: the mass-density of the universe is…

Astrophysics · Physics 2011-04-15 Neta A. Bahcall

The fluctuations in the Cosmic Microwave Background (CMB) intensity due to the Sunyaev-Zeldovich (SZ) effect are the sum of a thermal and a kinetic contribution. Separating the two components to measure the peculiar velocity of galaxy…

We aim to present a tutorial on the detection, parameter estimation and statistical analysis of compact sources (far galaxies, galaxy clusters and Galactic dense emission regions) in cosmic microwave background observations. The topic is of…

Instrumentation and Methods for Astrophysics · Physics 2011-01-05 D. Herranz , P. Vielva

We present three-dimensional hydrodynamical simulations of buoyant gas in a typical cluster environment. The hot matter was injected continuously into a small region off-set from the cluster centre. In agreement with previous analytic…

Astrophysics · Physics 2009-11-07 M. Bruggen , C. R. Kaiser , E. Churazov , T. A. Ensslin

We study the cosmic microwave background (CMB) anisotropy due to spherically symmetric nonlinear structures in flat universes with dust and a cosmological constant. By modeling a time-evolving spherical compensated void/lump by…

Astrophysics · Physics 2009-02-20 Nobuyuki Sakai , Kaiki Taro Inoue

We point out that two problems of observational cosmology, the facts i) that > 60% of the baryonic content of the universe is not observed at z=0 and ii) that the properties of small clusters do not agree with simple expectations, could be…

Astrophysics · Physics 2009-11-07 P. Valageas , R. Schaeffer , J. Silk

By combining large-scale mosaics of ROSAT PSPC, XMM-Newton, and Suzaku X-ray observations, we present evidence for large-scale motions in the intracluster medium of the nearby, X-ray bright Perseus Cluster. These motions are suggested by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 A. Simionescu , N. Werner , O. Urban , S. W. Allen , A. C. Fabian , J. S. Sanders , A. Mantz , P. E. J. Nulsen , Y. Takei

The X-ray background intensity around Lick count galaxies and rich clusters of galaxies is investigated in three ROSAT energy bands. It is found that the X-ray enhancements surrounding concentrations of galaxies exhibit significantly softer…

Astrophysics · Physics 2009-11-07 A. M. Soltan , M. J. Freyberg , G. Hasinger

The coupling of photons and baryons by Thomson scattering in the early universe imprints features in both the Cosmic Microwave Background (CMB) and matter power spectra. The former have been used to constrain a host of cosmological…

Astrophysics · Physics 2008-11-26 Martin White

Recent cosmic microwave background data in temperature and polarization have reached high precision in estimating all the parameters that describe the current so-called standard cosmological model. Recent results about the integrated…

Fluctuations in the cosmic microwave background (CMB) contain information which has been pivotal in establishing the current cosmological model. These data can also be used to test well-motivated additions to this model, such as cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-13 Stephen M. Feeney , Matthew C. Johnson , Daniel J. Mortlock , Hiranya V. Peiris
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