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We apply a mass reconstruction technique to simulated large-scale structure gravitational distortion maps, from 2.5' to 10 degree scales, for different cosmological scenarii. The projected mass is reconstructed using a non-parametric least…

Astrophysics · Physics 2007-05-23 L. Van Waerbeke , F. Bernardeau , Y. Mellier

The robust estimation of the tiny distortions (shears) of galaxy shapes caused by weak gravitational lensing in the presence of much larger shape distortions due to the point-spread function (PSF) has been widely investigated. One major…

Instrumentation and Methods for Astrophysics · Physics 2016-03-09 Alex Gurvich , Rachel Mandelbaum

A deterministic attitude estimation problem for a rigid body in a potential field, with bounded attitude and angular velocity measurement errors is considered. An attitude estimation algorithm that globally minimizes the attitude estimation…

Optimization and Control · Mathematics 2007-05-23 Amit K. Sanyal , Taeyoung Lee , Melvin Leok , N. Harris McClamroch

Weak lensing experiments are a powerful probe of cosmology through their measurement of the mass distribution of the universe. A challenge for this technique is to control systematic errors that occur when measuring the shapes of distant…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Alexandre Refregier , Tomasz Kacprzak , Adam Amara , Sarah Bridle , Barnaby Rowe

We propose a new technique for weak gravitational lensing in the radio band making use of polarization information. Since the orientation of a galaxy's polarized emission is both unaffected by lensing and is related to the galaxy's…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Michael L. Brown , Richard A. Battye

Investigating intrinsic alignments (IAs) of galaxy shapes is important not only to constrain cosmological parameters unbiasedly from gravitational lensing but also to extract cosmological information complimentary to galaxy clustering…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-26 Teppei Okumura , Atsushi Taruya

Probability density estimation is a core problem of statistics and signal processing. Moment methods are an important means of density estimation, but they are generally strongly dependent on the choice of feasible functions, which severely…

Machine Learning · Statistics 2023-07-06 Guangyu Wu , Anders Lindquist

Spatial intensity moments computed on images can be used as a probe of the centroid, size, and orientation of pixelized sources such as stars and galaxies. However, all measurements made on images suffer from errors due to undersampling and…

Instrumentation and Methods for Astrophysics · Physics 2020-12-11 Andrew K. Bradshaw

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

Attitude estimation is often a prerequisite for control of the attitude or orientation of mechanical systems. Current attitude estimation algorithms use coordinate representations for the group of rigid body orientations. All coordinate…

Optimization and Control · Mathematics 2007-05-23 Taeyoung Lee , Amit K. Sanyal , Melvin Leok , N. Harris McClamroch

We investigate the impact of the observed correlation between a galaxies shape and its surrounding density field on the measurement of third order weak lensing shear statistics. Using numerical simulations, we estimate the systematic error…

We propose a method that can determine the ellipticities of source stars of microlensing events produced by binary lenses. The method is based on the fact that the products of the caustic-crossing timescale, $\Delta t$, and the cosine of…

Astrophysics · Physics 2009-11-11 Cheongho Han , Heon-Young Chang

Weak gravitational lensing has become a powerful probe of large-scale structure and cosmological parameters. Precision weak lensing measurements require an understanding of the intrinsic alignment of galaxy ellipticities, which can in turn…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Jonathan Blazek , Matthew McQuinn , Uros Seljak

We propose elliptical graphical models based on conditional uncorrelatedness as a general- ization of Gaussian graphical models by letting the population distribution be elliptical instead of normal, allowing the fitting of data with…

Methodology · Statistics 2015-06-16 Daniel Vogel , Roland Fried

We consider microlensing of an elliptical source crossing a fold caustic. We derive a simple expression for the light curve of a source with uniform surface brightness that is accurate to third order in the ellipticity e (yielding errors of…

Astrophysics · Physics 2007-05-23 B. Scott Gaudi , Zoltan Haiman

We extend the Bayesian model fitting shape measurement method presented in Miller et al. (2007) and use the method to estimate the shear from the Shear TEsting Programme simulations (STEP). The method uses a fast model fitting algorithm…

Astrophysics · Physics 2009-11-13 T. D. Kitching , L. Miller , C. E. Heymans , L. van Waerbeke , A. F. Heavens

We constrain the post-Newtonian gravity parameter gamma on kiloparsec scales by comparing the masses of 15 elliptical lensing galaxies from the Sloan Lens ACS Survey as determined in two independent ways. The first method assumes only that…

Astrophysics · Physics 2009-11-11 Adam S. Bolton , Saul Rappaport , Scott Burles

Intrinsically aligned galaxy shapes are one of the most important systematics in cosmic shear measurements. So far theoretical studies of intrinsic alignments almost exclusively focus on their statistics at the two-point level. Results from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Philipp M. Merkel , Bjoern Malte Schaefer

In the literature, points and conics have been major features for camera geometric calibration. Although conics are more informative features than points, the loss of the conic property under distortion has critically limited the utility of…

Computer Vision and Pattern Recognition · Computer Science 2024-03-12 Chaehyeon Song , Jaeho Shin , Myung-Hwan Jeon , Jongwoo Lim , Ayoung Kim

The parameter-free reconstruction of the surface-mass density of clusters of galaxies is one of the principal applications of weak gravitational lensing. From the observable ellipticities of images of background galaxies, the tidal…

Astrophysics · Physics 2009-11-07 Marco Lombardi , Peter Schneider , Carlos Morales-Merino