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We study the correlation between the locations of galaxy-galaxy strong lensing candidates and tracers of large-scale structure from both weak lensing or X-ray emission. The COSMOS survey is a unique data set, combining deep, high resolution…

The cold dark matter (CDM) cosmological model unambigously predicts that a large number of haloes should survive as subhaloes when they are accreted into a larger halo. The CDM model would be ruled out if such substructures were shown not…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 Ran Li , Carlos S. Frenk , Shaun Cole , Liang Gao , Sownak Bose , Wojciech A. Hellwing

We report on the detection of gravitational lensing magnification by a population of galaxy groups, at a significance level of 4.9 sigma. Using X-ray selected groups in the COSMOS 1.64 deg^2 field, and high-redshift Lyman break galaxies as…

We present a novel deep learning method to separately extract the two-dimensional flux information of the foreground galaxy (deflector) and background system (source) of Galaxy-Galaxy Strong Lensing events using U-Net (GGSL-Unet for short).…

Image segmentation is a key topic in image processing and computer vision with applications such as scene understanding, medical image analysis, robotic perception, video surveillance, augmented reality, and image compression, among many…

Computer Vision and Pattern Recognition · Computer Science 2020-11-17 Shervin Minaee , Yuri Boykov , Fatih Porikli , Antonio Plaza , Nasser Kehtarnavaz , Demetri Terzopoulos

We investigate how strong lensing of dusty, star-forming galaxies by foreground galaxies can be used as a probe of dark matter halo substructure. We find that spatially resolved spectroscopy of lensed sources allows dramatic improvements to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Yashar Hezaveh , Neal Dalal , Gilbert Holder , Michael Kuhlen , Daniel Marrone , Norman Murray , Joaquin Vieira

In the CDM scenario, dark matter halos are assembled hierarchically from smaller subunits. A long-standing problem with this picture is that the number of sub-halos predicted by CDM simulations is orders of magnitudes higher than the known…

Astrophysics · Physics 2014-11-18 T. Riehm , E. Zackrisson , O. Moeller , E. Mortsell , K. Wiik

We present an automated approach to detect and extract information from the astronomical datasets on the shapes of such objects as galaxies, star clusters and, especially, elongated ones such as the gravitational lenses. First, the…

Instrumentation and Methods for Astrophysics · Physics 2019-09-10 S. S. Mirzoyan , H. Khachatryan , G. Yegorian , V. G. Gurzadyan

The distribution of dark and luminous matter can be mapped around galaxies that gravitationally lens background objects into arcs or Einstein rings. New surveys will soon observe hundreds of thousands of galaxy lenses, and current,…

Specular reflections pose a significant challenge for object segmentation, as their sharp intensity transitions often mislead both conventional algorithms and deep learning based methods. However, as the specular reflection must lie on the…

Image and Video Processing · Electrical Eng. & Systems 2026-02-26 Katja Kossira , Yunxuan Zhu , Jürgen Seiler , André Kaup

Galactic sized gravitational lenses are simulated by combining a cosmological N-body simulation and models for the baryonic component of the galaxy. The lens caustics, critical curves, image locations and magnification ratios are calculated…

Astrophysics · Physics 2009-11-10 Adam Amara , R. Benton Metcalf , Thomas J. Cox , Jeremiah P. Ostriker

Galaxy-scale strong gravitational lenses are valuable objects for a variety of astrophysical and cosmological applications. Strong lensing galaxies are rare, so efficient search methods, such as convolutional neural networks, are often used…

Astrophysics of Galaxies · Physics 2025-02-17 Yuichiro Ishida , Kenneth C. Wong , Anton T. Jaelani , Anupreeta More

The cold dark matter (DM) model predicts that every galaxy contains thousands of DM subhalos; almost all other DM models include a physical process that smooths away the subhalos. The subhalos are invisible, but could be detected via strong…

This review presents various image segmentation methods using complex networks. Image segmentation is one of the important steps in image analysis as it helps analyze and understand complex images. At first, it has been tried to classify…

Computer Vision and Pattern Recognition · Computer Science 2024-01-08 Amin Rezaei , Fatemeh Asadi

We present a halo model prediction of the image separation distribution of strong lenses. Our model takes account of the subhalo population, which has been ignored in previous studies, as well as the conventional halo population. Halos and…

Astrophysics · Physics 2009-11-13 Masamune Oguri

Strong gravitational lenses are a singular probe of the universe's small-scale structure $\unicode{x2013}$ they are sensitive to the gravitational effects of low-mass $(<10^{10} M_\odot)$ halos even without a luminous counterpart. Recent…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-24 Sebastian Wagner-Carena , Jaehoon Lee , Jeffrey Pennington , Jelle Aalbers , Simon Birrer , Risa H. Wechsler

Context: The number of known strong gravitational lenses is expected to grow substantially in the next few years. The statistical combination of large samples of lenses has the potential of providing strong constraints on the inner…

Astrophysics of Galaxies · Physics 2021-07-07 Alessandro Sonnenfeld , Marius Cautun

Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still…

As established in previous papers of this series, observables in highly distorted and magnified multiple images caused by the strong gravitational lensing effect can be used to constrain the distorting properties of the gravitational lens…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 Joyce Lin , Jenny Wagner , Richard E. Griffiths