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The topology of weak lensing fields is studied using the 2-dimensional genus statistic. Simulated fields of the weak lensing convergence are used to focus on the effect of nonlinear gravitional evolution and to model the statistical errors…

Astrophysics · Physics 2009-10-31 Takahiko Matsubara , Bhuvnesh Jain

We consider the weak detection problem in a rank-one spiked Wigner data matrix where the signal-to-noise ratio is small so that reliable detection is impossible. We propose a hypothesis test on the presence of the signal by utilizing the…

Statistics Theory · Mathematics 2022-06-28 Hye Won Chung , Ji Oon Lee

Weak gravitational lensing of distant galaxies by foreground structures has proven to be a powerful tool to study the mass distribution in the universe. The advent of panoramic cameras on 4m class telescope has led to a first generation of…

Astrophysics · Physics 2019-10-23 Henk Hoekstra

We describe a method to estimate the mass distribution of a gravitational lens and the position of the sources from combined strong and weak lensing data. The algorithm combines weak and strong lensing data in a unified way producing a…

Astrophysics · Physics 2008-11-26 J. M. Diego , M. Tegmark , P. Protopapas , H. B. Sandvik

We revise and extend the stochastic approach to cumulative weak lensing (hereafter the sGL method) first introduced in Ref. [1]. Here we include a realistic halo mass function and density profiles to model the distribution of mass between…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-19 Kimmo Kainulainen , Valerio Marra

Future weak lensing surveys will directly probe the density fluctuation in the universe. Recent studies have shown how the statistics of the weak lensing convergence field is related to the statistics of collapsed objects. Extending earlier…

Astrophysics · Physics 2008-11-26 Dipak Munshi

We explore the stability of the variance and skewness of the cosmic gravitational convergence field, using two different approaches: first we simulate a whole MEGACAM survey (100 sq. degrees). The reconstructed mass map, obtained from a…

Astrophysics · Physics 2007-05-23 A. Thion , Y. Mellier , F. Bernardeau , E. Bertin , T. Erben , L. van Waerbeke

The next generation of weak lensing surveys will measure the matter distribution of the local Universe with unprecedented precision, allowing the resolution of non-Gaussian features of the convergence field. This encourages the use of…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-17 Dominik Zürcher , Janis Fluri , Virginia Ajani , Silvan Fischbacher , Alexandre Refregier , Tomasz Kacprzak

We investigate the potential of weak gravitational lensing maps to differentiate between distinct cosmological models, considering cosmic variance due to a limited map extension and the presence of noise. We introduce a measure of the…

Astrophysics · Physics 2009-11-07 Antonio Guimarães

We study Bayesian inference methods for solving linear inverse problems, focusing on hierarchical formulations where the prior or the likelihood function depend on unspecified hyperparameters. In practice, these hyperparameters are often…

Numerical Analysis · Mathematics 2018-08-01 Qingping Zhou , Wenqing Liu , Jinglai Li , Youssef M. Marzouk

One of the most powerful techniques to study the dark sector of the Universe is weak gravitational lensing. In practice, to infer the reduced shear, weak lensing measures galaxy shapes, which are the consequence of both the intrinsic…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-07 Sami-Matias Niemi , Thomas Kitching , Mark Cropper

Weak gravitational lensing observations are a key science driver for the NASA Wide Field Infrared Survey Telescope (WFIRST). To validate the performance of the WFIRST infrared detectors, we have performed a laboratory emulation of weak…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 Suresh Seshadri , Charles Shapiro , Timothy Goodsall , Jason Fucik , Christopher M. Hirata , Jason Rhodes , Barnaby Rowe , Roger Smith

The L1-regularized Gaussian maximum likelihood estimator (MLE) has been shown to have strong statistical guarantees in recovering a sparse inverse covariance matrix, or alternatively the underlying graph structure of a Gaussian Markov…

Machine Learning · Computer Science 2013-06-14 Cho-Jui Hsieh , Matyas A. Sustik , Inderjit S. Dhillon , Pradeep Ravikumar

Taking into account noise from intrinsic ellipticities of source galaxies, in this paper, we study the peak statistics in weak-lensing convergence maps around clusters of galaxies and beyond. We emphasize how the noise peak statistics is…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Zuhui Fan , Huanyuan Shan , Jiayi Liu

We propose a Likelihood Matching approach for training diffusion models by first establishing an equivalence between the likelihood of the target data distribution and a likelihood along the sample path of the reverse diffusion. To…

Machine Learning · Statistics 2026-01-23 Lei Qian , Wu Su , Yanqi Huang , Song Xi Chen

We study the cosmological information of weak lensing (WL) peaks, focusing on two other statistics besides their abundance: the stacked tangential-shear profiles and the peak-peak correlation function. We use a large ensemble of simulated…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Laura Marian , Robert E. Smith , Stefan Hilbert , Peter Schneider

We develop a method to simulate galaxy-galaxy weak lensing by utilizing all-sky, light-cone simulations and their inherent halo catalogs. Using the mock catalog to study the error covariance matrix of galaxy-galaxy weak lensing, we compare…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Masato Shirasaki , Masahiro Takada , Hironao Miyatake , Ryuichi Takahashi , Takashi Hamana , Takahiro Nishimichi , Ryoma Murata

Reverberation mapping offers one of the best techniques for studying the inner regions of QSOs. It is based on cross-correlating continuum and emission-line light curves. New time-resolved optical surveys will produce well sampled light…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 S. Fine , T. Shanks , S. M. Croom , P. Green , B. C. Kelly , E. Berge , R. Chornock , W. S. Burgett , E. A. Magnier , P. A. Price

Weak gravitational lensing is a promising tool for the study of the mass distribution in the Universe. Here we report some partial results that show how lensing maps can be used to differentiate between cosmological models. We pay special…

Astrophysics · Physics 2007-05-23 Antonio C. C. Guimarães

An accurate covariance matrix is essential for obtaining reliable cosmological results when using a Gaussian likelihood. In this paper we study the covariance of pseudo-$C_\ell$ estimates of tomographic cosmic shear power spectra. Using two…