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We present a novel way of using neural networks (NN) to estimate the redshift distribution of a galaxy sample. We are able to obtain a probability density function (PDF) for each galaxy using a classification neural network. The method is…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-08 Christopher Bonnett

The nonlinear perturbation theory of gravitational instability is extended to include effects of both biasing and redshift-space distortions, which are inevitable in predicting observable quantities in galaxy surveys. The precise…

Astrophysics · Physics 2014-11-18 Takahiko Matsubara

We present a scheme based on artificial neural networks (ANN) to estimate the line-of-sight velocities of individual galaxies from an observed redshift-space galaxy distribution. We find an estimate of the peculiar velocity at a galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-09 Hongxiang Chen , Jie Wang , Tianxiang Mao , Juntao Ma , Yuxi Meng , Baojiu Li , Yan-Chuan Cai , Mark Neyrinck , Bridget Falck , Alexander S. Szalay

We explore how information in images of nearby galaxies can be used to estimate their distance. We train a convolutional Neural Network (NN) to do this, using galaxy images from the Illustris simulation. We show that if the NN is trained on…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-21 Kevin M. Quigley , Samuel Hori , Rupert A. C. Croft

In recent years, deep learning approaches have achieved state-of-the-art results in the analysis of point cloud data. In cosmology, galaxy redshift surveys resemble such a permutation invariant collection of positions in space. These…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 Sotiris Anagnostidis , Arne Thomsen , Tomasz Kacprzak , Tilman Tröster , Luca Biggio , Alexandre Refregier , Thomas Hofmann

Redshift-space distortions (RSD) in galaxy redshift surveys generally break both the isotropy and homogeneity of galaxy distribution. While the former aspect is particularly highlighted as a probe of growth of structure induced by gravity,…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Atsushi Taruya , Shohei Saga , Michel-Andrès Breton , Yann Rasera , Tomohiro Fujita

We develop a machine learning approach to reconstructing the cosmological initial conditions from late-time dark matter halo number density fields in redshift space, with the goal of improving sensitivity to cosmological parameters, and in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Jelte Bottema , Thomas Flöss , P. Daniel Meerburg

Second-order optimizers hold intriguing potential for deep learning, but suffer from increased cost and sensitivity to the non-convexity of the loss surface as compared to gradient-based approaches. We introduce a coordinate descent method…

Machine Learning · Computer Science 2020-06-19 Ravi G. Patel , Nathaniel A. Trask , Mamikon A. Gulian , Eric C. Cyr

Numerical simulations show that redshift space distortions (RSD) introduce strong scale dependence in the power spectra of halos, with ten percent deviations relative to linear theory predictions even on relatively large scales (k<0.1h/Mpc)…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Zvonimir Vlah , Uroš Seljak , Teppei Okumura , Vincent Desjacques

Data-driven approaches play a crucial role in space computing, and our paper focuses on analyzing data to learn more about celestial objects. Photometric redshift, a measure of the shift of light towards the red part of the spectrum, helps…

Instrumentation and Methods for Astrophysics · Physics 2024-11-22 Krishna Chunduri , Mithun Mahesh

The combination of two- and three-point clustering statistics of galaxies and the underlying matter distribution has the potential to break degeneracies between cosmological parameters and nuisance parameters and can lead to significantly…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 Oliver Leicht , Tobias Baldauf , James Fergusson , Paul Shellard

Deep Neural Networks (DNNs) have provably enhanced the state-of-the-art Neural Machine Translation (NMT) with their capability in modeling complex functions and capturing complex linguistic structures. However NMT systems with deep…

Computation and Language · Computer Science 2017-05-03 Mingxuan Wang , Zhengdong Lu , Jie Zhou , Qun Liu

DESI is a groundbreaking international project to observe more than 40 million quasars and galaxies over a 5-year period to create a 3D map of the sky. This map will enable us to probe multiple aspects of cosmology, from dark energy to…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-25 Julien Taran

Measuring distances of cosmological sources such as galaxies, stars and quasars plays an increasingly critical role in modern cosmology. Obtaining the optical spectrum and consequently calculating the redshift as a distance indicator could…

Astrophysics of Galaxies · Physics 2022-01-13 Aidin Momtaz , Mohammad Hossein Salimi , Soroush Shakeri

The simplest theory describing large-scale redshift-space distortions (RSD), based on linear theory and distant galaxies, depends on the growth of cosmological structure, suggesting that strong tests of General Relativity can be constructed…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Lado Samushia , Will J. Percival , Alvise Raccanelli

Nighttime light (NTL) remote sensing observation serves as a unique proxy for quantitatively assessing progress toward meeting a series of Sustainable Development Goals (SDGs), such as poverty estimation, urban sustainable development, and…

Computer Vision and Pattern Recognition · Computer Science 2024-10-30 Lixian Zhang , Runmin Dong , Shuai Yuan , Jinxiao Zhang , Mengxuan Chen , Juepeng Zheng , Haohuan Fu

This study aims to improve the photometric redshifts (photo-$z$s) of galaxies by integrating two contemporary methods: template-fitting and machine learning. Finding the synergy between these two methods was not a high priority in the past,…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-30 Ishaq Y. K. Alshuaili , John Y. H. Soo , Mohd Zubir Mat Jafri , Yasmin Rafid

Line segment detection is a fundamental low-level task in computer vision, and improvements in this task can impact more advanced methods that depend on it. Most new methods developed for line segment detection are based on Convolutional…

Computer Vision and Pattern Recognition · Computer Science 2024-11-21 Sebastian Janampa , Marios Pattichis

Deep Neural Network (DNN)-based image reconstruction, despite many successes, often exhibits uneven fidelity between high and low spatial frequency bands. In this paper we propose the Learning Synthesis by DNN (LS-DNN) approach where two…

Computer Vision and Pattern Recognition · Computer Science 2018-11-21 Mo Deng , Shuai Li , George Barbastathis

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