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Related papers: Constraints on the fluctuation amplitude and densi…

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Using mean relative peculiar velocity measurements for pairs of galaxies, we estimate the cosmological density parameter $\Omega_m$ and the amplitude of density fluctuations $\sigma_8$. Our results suggest that our statistic is a robust and…

Evolution of the cluster temperature function is extremely sensitive to the mean matter density of the universe. Current measurements based on cluster temperature surveys indicate that Omega_M ~ 0.3 with a 1-sigma statistical error ~0.1,…

Astrophysics · Physics 2009-10-31 G. M. Voit

Cosmological parameters such as $\Omega_{\rm{M}}$ and $\sigma_{8}$ can be measured indirectly using various methods, including galaxy cluster abundance and cosmic shear. These measurements constrain the composite parameter $S_{8}$, leading…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-27 Roan Haggar , Yuba Amoura , Charlie T. Mpetha , James E. Taylor , Kris Walker , Chris Power

In this work, we analyse the temperature fluctuations of the cosmic microwave background radiation observed by COBE and show that the distribution can be fitted by a fractal distribution with a fractal dimension $ D= 1.43 \pm 0.07 $. This…

We present a maximum likelihood analysis of cosmological parameters from measurements of the aperture mass up to 35 arcmin, using simulated and real cosmic shear data. A four-dimensional parameter space is explored which examines the mean…

Astrophysics · Physics 2009-11-07 L. Van Waerbeke , Y. Mellier , R. Pello , U-L. Pen , H. J. McCracken , B. Jain

The abundance and mass distribution of galaxy clusters is a sensitive probe of cosmological parameters, through the sensitivity of the high-mass end of the halo mass function to $\Omega_m$ and $\sigma_8$. While galaxy cluster surveys have…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-15 M. Regamey , D. Eckert , R. Seppi , W. Hartley , K. Umetsu , S. Tam , D. Gerolymatou

The ROSAT Deep Cluster Survey (RDCS) has provided a new large deep sample of X-ray selected galaxy clusters. Observables such as the flux number counts n(S), the redshift distribution n(z) and the X-ray luminosity function (XLF) over a…

Astrophysics · Physics 2009-10-31 S. Borgani , P. Rosati , P. Tozzi , C. Norman

We present results derived from a high-resolution cosmological N-body simulation in which the equations of motion have been changed to account for MOdified Newtonian Dynamics (MOND). It is shown that a low-Omega0 MONDian model with an…

Astrophysics · Physics 2007-05-23 Alexander Knebe

We discuss a new method which is potentially capable of constraining cosmological parameters using observations of giant luminous arcs in rich X-ray clusters of galaxies. The mass profile and the mass normalization of the lenses are…

Astrophysics · Physics 2009-11-10 M. Sereno , G. Longo

We use gravitational lens models and X-ray spectral analysis of ten X-ray luminous galaxy clusters at z~0.2 to study the impact of cluster substructure on attempts to normalize the matter power spectrum. We estimate that unrelaxed clusters…

We study Sunyaev-Zeldovich Effect (SZE) cluster counts in different cosmologies. It is found that even without the full knowledge of the redshift distribution of SZE clusters, one can still readily distinguish a flat universe with a…

Astrophysics · Physics 2009-10-31 Zuhui Fan , Tzihong Chiueh

We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06<z<0.7. The observed dark matter and total mass (dark-plus-luminous matter) profiles can…

Astrophysics · Physics 2008-11-26 R. W. Schmidt , S. W. Allen

In the standard flat cosmological constant ($\Lambda$) cold dark matter (CDM) cosmology, a model of two populations of lens halos for strong gravitational lensing can reproduce the results of the Jodrell-Bank VLA Astrometric Survey (JVAS)…

Astrophysics · Physics 2009-11-10 Da-Ming Chen

In this paper, we discuss improvements of the Suto et al. (2000) model, in the light of recent theoretical developments (new theoretical mass functions, a more accurate mass-temperature relation and an improved bias model) to predict the…

Astrophysics · Physics 2009-11-23 A. Del Popolo , N. Ercan , S. Yesilyurt

We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and…

The COBE microwave background temperature fluctuations and the abundance of local rich clusters of galaxies provide the two most powerful constraints on cosmological models. When all variants of the standard cold dark matter (CDM) model are…

Astrophysics · Physics 2009-10-30 Renyue Cen

The relationships between the X-ray determined bolometric luminosity Lx, the temperature T of the intracluster gas, and the optical measured velocity dispersion sigma of the cluster galaxies are updated for galaxy clusters using the largest…

Astrophysics · Physics 2009-10-31 Xiang-Ping Wu , Yan-Jie Xue , Li-Zhi Fang

This is the third of a series of papers in which we derive simultaneous constraints on cosmological parameters and X-ray scaling relations using observations of the growth of massive, X-ray flux-selected galaxy clusters. Our data set…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 David Rapetti , Steven W. Allen , Adam Mantz , Harald Ebeling

We address the possibility of bounding the spectral index $n$ of primordial density fluctuations, using both the cosmic microwave background (cmb) anisotropy and data on galaxies and clusters. Each piece of galaxy and cluster data is…

Astrophysics · Physics 2008-02-03 Andrew R Liddle , David H Lyth

We investigate the relationship between soft \xray luminosity and mass for low redshift clusters of galaxies by comparing observed number counts to expectations of $\Lambda$CDM cosmologies. We use a three-parameter model for the conditional…

Astrophysics · Physics 2008-11-26 R. Stanek , A. E. Evrard , H. Böhringer , P. Schuecker , B. Nord