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The possibility of determining cosmological parameters on the basis of a wide set of observational data including the Abell-ACO cluster power spectrum and mass function, peculiar velocities of galaxies, the distribution of Ly-$\alpha$…

Astrophysics · Physics 2007-05-23 B. Novosyadlyj , R. Durrer , S. Gottloeber , V. N. Lukash , S. Apunevych

We present a new geometrical method which uses weak gravitational lensing effects in clusters to constrain the cosmological parameters Omega and Lambda. On each background galaxy, a cluster induces a convergence and a shear terms, which…

Astrophysics · Physics 2007-05-23 L. Gautret , B. Fort , Y. Mellier

The measurement of cosmological parameters is investigated in a representation of the least-action method that uses a redshift-space dataset to simultaneously constrain the real-space fields $\delta$,$\b v$. This method is robust in…

Astrophysics · Physics 2009-10-31 Mikel Susperregi

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

We compute the accuracy with which Omega and Lambda can be measured by combining future SN Ia and CMB experiments, deriving a handy expression for the SN Ia Fisher information matrix. The two data sets are found to be highly complementary:…

Astrophysics · Physics 2007-05-23 Max Tegmark , Daniel J. Eisenstein , Wayne Hu

We review observational tests for the homogeneity of the Universe on large scales. Redshift and peculiar velocity surveys, radio sources, the X-Ray Background, the Lyman-$\alpha$ forest and the Cosmic Microwave Background are used to set…

Astrophysics · Physics 2007-05-23 Ofer Lahav

We use three strong lensing clusters to constrain the cosmological parameters Omega_m and Omega_lambda. Recent HST observations of galaxy clusters reveal a large number of multiple images, which are predicted to be at different redshifts.…

Astrophysics · Physics 2007-05-23 G. Golse , J. -P. Kneib , G. Soucail

(Abridged) We develop median statistics that provide powerful alternatives to chi-squared likelihood methods and require fewer assumptions about the data. Applying median statistics to Huchra's compilation of nearly all estimates of the…

Astrophysics · Physics 2009-10-31 J. Richard Gott , Michael S. Vogeley , Silviu Podariu , Bharat Ratra

The evolution of the galaxy cluster abundance depends sensitively on the value of the cosmological density parameter, Omega_0. Recent ASCA data are used to quantify this evolution as measured by the X-ray temperature function. A chi^2…

Astrophysics · Physics 2009-10-30 V. R. Eke , S. Cole , C. S. Frenk , J. P. Henry

We consider the weakly supervised binary classification problem where the labels are randomly flipped with probability $1- {\alpha}$. Although there exist numerous algorithms for this problem, it remains theoretically unexplored how the…

Machine Learning · Computer Science 2019-07-16 Xinyang Yi , Zhaoran Wang , Zhuoran Yang , Constantine Caramanis , Han Liu

Asymmetric statistical errors arise for experimental results obtained by Maximum Likelihood estimation, in cases where the number of results is finite and the log likelihood function is not a symmetric parabola. This note discusses how…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Roger Barlow

We present a new framework for modelling discrete kinematic data. Current techniques typically involve binning. Our approach works directly with the discrete data and uses maximum-likelihood methods to assess the probability of the dataset…

Astrophysics of Galaxies · Physics 2015-06-17 Laura L. Watkins , Glenn van de Ven , Mark den Brok , Remco C. E. van den Bosch

The possibility of detecting weak lensing effects from deep wide field imaging surveys has open new means of probing the large-scale structures of the Universe and measuring cosmological parameters. In this paper we present a systematic…

Astrophysics · Physics 2010-04-06 F. Bernardeau , L. van Waerbeke , Y. Mellier

Recent cosmological tensions pose difficulties for $\Lambda$CDM. Forthcoming facilities will be able to check whether these tensions result from systematic effects or indeed with the $\Lambda$CDM model itself. However, these new data will…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-12 Dinko Milaković , John K. Webb

In this paper we present a scale free method to determine the cosmological parameters (Omega_m, Omega_Lambda). The method is based on the requirement of isotropy of the distribution of orientations of cosmological filaments. The current…

Astrophysics · Physics 2009-11-07 M. Weidinger , P. Moller , J. P. U. Fynbo , B. Thomsen , M. P. Egholm

The analysis of scientific data and complex multivariate systems requires information quantities that capture relationships among multiple random variables. Recently, new information-theoretic measures have been developed to overcome the…

Machine Learning · Computer Science 2024-06-10 Mustapha Bounoua , Giulio Franzese , Pietro Michiardi

The anthropic explanation for the peculiarly small observed value of the cosmological constant $\Lambda_{\rm obs}$ argues that this value promotes the formation of stars, planets, and ultimately of observers such as ourselves. I show that a…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-18 Daniele Sorini

We determine the density parameters $\Omega_m$ of gravitating matter and $\Omega_{\Lambda}$ of vacuum energy, by making a $\chi^2$ fit to nine independent astrophysical constraints. Paying rigorous attention to statistical detail, we find…

Astrophysics · Physics 2007-05-23 Matts Roos , S. M. Harun-or-Rashid

I present several simple figures to illustrate cosmology and structure formation in a nutshell. Then I discuss the following argument: if we assume that Omega_{Lambda} = 0 then the CMB results favor high Omega_{m} while the supernova…

Astrophysics · Physics 2007-05-23 Charles H. Lineweaver

We review observational tests for the homogeneity of the Universe on large scales. Redshift and peculiar velocity surveys, radio sources, the X-Ray Background, the Lyman-alpha forest and the Cosmic Microwave Background are used to set…

Astrophysics · Physics 2016-08-30 Ofer Lahav