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Weak gravitational lensing provides a direct statistical measure of the dark matter distribution. The variance is easiest to measure, which constrains the degenerate product \sigma_8\Omega^0.6. The degeneracy is broken by measuring the…

Weak lensing by large-scale structure allows a direct measure of the dark matter distribution. We have used parallel images taken with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope to measure weak lensing, or…

The resolution of optical imaging is classically limited by the width of the point-spread function, which in turn is determined by the Rayleigh length. Recently, spatial-mode demultiplexing (SPADE) has been proposed as a method to achieve…

Quantum Physics · Physics 2025-02-26 Giuseppe Buonaiuto , Cosmo Lupo

In this paper, we proposed to investigate unsupervised anomaly detection in Synthetic Aperture Radar (SAR) images. Our approach considers anomalies as abnormal patterns that deviate from their surroundings but without any prior knowledge of…

Computer Vision and Pattern Recognition · Computer Science 2022-10-31 Max Muzeau , Chengfang Ren , Sébastien Angelliaume , Mihai Datcu , Jean-Philippe Ovarlez

We examine scatter and bias in weak lensing selected clusters, employing both an analytic model of dark matter haloes and numerical mock data of weak lensing cluster surveys. We pay special attention to effects of the diversity of dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Takashi Hamana , Masamune Oguri , Masato Shirasaki , Masanori Sato

We describe an efficient algorithm for calculating the statistics of weak lensing by large-scale structure based on a tiled set of independent particle-mesh N-body simulations which telescope in resolution along the line of sight. This…

Astrophysics · Physics 2008-11-26 Martin White , Wayne Hu

Shadow detection is a fundamental and challenging task in many computer vision applications. Intuitively, most shadows come from the occlusion of light by the object itself, resulting in the object and its shadow being contiguous (referred…

Computer Vision and Pattern Recognition · Computer Science 2024-08-08 Yonghui Wang , Shaokai Liu , Li Li , Wengang Zhou , Houqiang Li

We present the application of the pseudo-spectrum method to galaxy-galaxy lensing. We derive explicit expressions for the pseudo-spectrum analysis of the galaxy-shear cross spectrum, which is the Fourier space counterpart of the stacked…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-25 Chiaki Hikage , Masamune Oguri

SWIFT J1658.2-4242 is an X-ray transient discovered recently in the Galactic plane, with severe X-ray absorption corresponding to an equivalent hydrogen column density of $N_{\rm H,abs}\sim2\times10^{23}$ cm$^{-2}$. Using new Chandra and…

High Energy Astrophysical Phenomena · Physics 2019-05-01 Chichuan Jin , Gabriele Ponti , Guangxing Li , David Bogensberger

The free streaming length of dark matter particles determines the abundance of structure on sub-galactic scales. We present a statistical technique, amendable to any parameterization of subhalo density profile and mass function, to probe…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-29 Daniel Gilman , Simon Birrer , Tommaso Treu , Charles R. Keeton , Anna Nierenberg

Light scattering by dust particles is often modeled assuming the dust is spherical for numerical simplicity and speed. However, real dust particles have highly irregular morphologies that significantly affect their scattering properties. We…

Earth and Planetary Astrophysics · Physics 2025-11-14 Zhe-Yu Daniel Lin , Alycia J. Weinberger , Evgenij Zubko , Jessica A. Arnold , Gorden Videen

Scatter due to interaction of photons with the imaged object is a fundamental problem in X-ray Computed Tomography (CT). It manifests as various artifacts in the reconstruction, making its abatement or correction critical for image quality.…

Medical Physics · Physics 2024-01-30 Berk Iskender , Yoram Bresler

We consider long-slit emission-line spectra of galactic nuclei when the slit is wider than the instrumental PSF, and the target has large velocity gradients. The finite width of the slit generates complex distributions of brightness at a…

Astrophysics · Physics 2015-06-24 Witold Maciejewski , James Binney

We derive general equations for non-linearity corrections and statistical uncertainty (variance) estimates for data acquired with near-infrared detectors employing correlated double sampling, multiple correlated double sampling (Fowler…

Astrophysics · Physics 2009-11-10 W. D. Vacca , M. C. Cushing , J. T. Rayner

Cosmic shear is a primary cosmological probe for several present and upcoming surveys investigating dark matter and dark energy, such as Euclid or WFIRST. The probe requires an extremely accurate measurement of the shapes of millions of…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-04 Malte Tewes , Thibault Kuntzer , Reiko Nakajima , Frédéric Courbin , Hendrik Hildebrandt , Tim Schrabback

We derive expressions, in terms of "polar shapelets", for the image distortion operations associated with weak gravitational lensing. Shear causes galaxy shapes to become elongated, and is sensitive to the second derivative of the projected…

Astrophysics · Physics 2008-11-26 Richard Massey , Barnaby Rowe , Alexandre Refregier , David J. Bacon , Joel Berge

The ratio of the average tangential shear signal of different weak lensing source populations around the same lens galaxies, also known as a shear ratio, provides an important test of lensing systematics and a potential source of…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-01 Ni Emas , Chris Blake , Rossana Ruggeri , Anna Porredon

I propose a spatial-mode demultiplexing (SPADE) measurement scheme for the far-field imaging of spatially incoherent optical sources. For any object too small to be resolved by direct imaging under the diffraction limit, I show that SPADE…

Optics · Physics 2017-03-01 Mankei Tsang

Deep-learning based salient object detection methods achieve great improvements. However, there are still problems existing in the predictions, such as blurry boundary and inaccurate location, which is mainly caused by inadequate feature…

Computer Vision and Pattern Recognition · Computer Science 2021-08-24 Han Sun , Yetong Bian , Ningzhong Liu , Huiyu Zhou

Weak lensing leads to the non-Gaussian magnification distribution of standard candles at given redshift $z$, $p(\mu|z)$. In this paper, we give accurate and simple empirical fitting formulae of the weak lensing numerical simulation results…

Astrophysics · Physics 2009-10-31 Yun Wang
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