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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

We present the UNIT $N$-body cosmological simulations project, designed to provide precise predictions for nonlinear statistics of the galaxy distribution. We focus on characterizing statistics relevant to emission line and luminous red…

N-body simulations that follow only a collisionless dark matter component have failed to produce galaxy halos or substructure within dense environments. We investigate the `over-merging' problem analytically and with numerical simulations,…

Astrophysics · Physics 2009-10-28 Ben Moore , Neal Katz , George Lake

The spatial curvature ($\Omega_K$) of the Universe is one of the most fundamental quantities that could give a link to the early universe physics. In this paper we develop an approximate method to compute the nonlinear matter power…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Ryo Terasawa , Ryuichi Takahashi , Takahiro Nishimichi , Masahiro Takada

We introduce a novel technique for constraining cosmological parameters and galaxy assembly bias using non-linear redshift-space clustering of galaxies. We scale cosmological N-body simulations and insert galaxies with the SubHalo Abundance…

We model the galaxy formation in a series of high-resolution N-body simulations using the semi-analytical approach. Unlike many earlier investigations based on semi-analytical models, we make use of the subhalos resolved in the $N$-body…

Astrophysics · Physics 2009-10-19 X. Kang , Y. P. Jing , H. J. Mo , G. Boerner

To maximize the amount of information extracted from cosmological datasets, simulations that accurately represent these observations are necessary. However, traditional simulations that evolve particles under gravity by estimating…

We train graph neural networks on halo catalogues from Gadget N-body simulations to perform field-level likelihood-free inference of cosmological parameters. The catalogues contain $\lesssim$5,000 halos with masses $\gtrsim…

During their formative years, radiology trainees are required to interpret hundreds of mammograms per month, with the objective of becoming apt at discerning the subtle patterns differentiating benign from malignant lesions. Unfortunately,…

Image and Video Processing · Electrical Eng. & Systems 2020-10-26 Cyril Zakka , Ghida Saheb , Elie Najem , Ghina Berjawi

Upcoming Large Scale Structure surveys aim to achieve an unprecedented level of precision in measuring galaxy clustering. However, accurately modeling these statistics may require theoretical templates that go beyond second-order…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-21 M. Icaza-Lizaola , Yong-Seon Song , Minji Oh , Yi Zheng

Generating realistic images is difficult, and many formulations for this task have been proposed recently. If we restrict the task to that of generating a particular class of images, however, the task becomes more tractable. That is to say,…

Computer Vision and Pattern Recognition · Computer Science 2020-03-06 David Berthelot , Peyman Milanfar , Ian Goodfellow

We build a field level emulator for cosmic structure formation that is accurate in the nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-02 Drew Jamieson , Yin Li , Renan Alves de Oliveira , Francisco Villaescusa-Navarro , Shirley Ho , David N. Spergel

Analysis of large galaxy surveys requires confidence in the robustness of numerical simulation methods. The simulations are used to construct mock galaxy catalogs to validate data analysis pipelines and identify potential systematics. We…

In this work, we propose a novel procedure for video super-resolution, that is the recovery of a sequence of high-resolution images from its low-resolution counterpart. Our approach is based on a "sequential" model (i.e., each…

Computer Vision and Pattern Recognition · Computer Science 2016-02-16 Patrick Héas , Angélique Drémeau , Cédric Herzet

In cosmological $N$-body simulations, the representation of dark matter as discrete "macroparticles" suppresses the growth of structure, such that simulations no longer reproduce linear theory on small scales near $k_{\rm Nyquist}$. Marcos…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-04 Lehman H. Garrison , Daniel J. Eisenstein , Douglas Ferrer , Marc V. Metchnik , Philip A. Pinto

We present a generative model that learns to synthesize human motion from limited training sequences. Our framework provides conditional generation and blending across multiple temporal resolutions. The model adeptly captures human motion…

Computer Vision and Pattern Recognition · Computer Science 2024-11-26 David Eduardo Moreno-Villamarín , Anna Hilsmann , Peter Eisert

Real-time generative game engines represent a paradigm shift in interactive simulation, promising to replace traditional graphics pipelines with neural world models. However, existing approaches are fundamentally constrained by the ``Memory…

Artificial Intelligence · Computer Science 2026-02-03 Wei Zeng , Xuchen Li , Ruili Feng , Zhen Liu , Fengwei An , Jian Zhao

Generative adversarial networks (GAN) and generative diffusion models (DM) have been widely used in real-world image super-resolution (Real-ISR) to enhance the image perceptual quality. However, these generative models are prone to…

Computer Vision and Pattern Recognition · Computer Science 2024-08-20 Du Chen , Zhengqiang Zhang , Jie Liang , Lei Zhang

We develop a hybrid galaxy formation model which uses outputs from an N-body simulation to follow the merger histories (or ``merger trees'') of dark matter halos and treats baryonic processes, such as the cooling of gas within halos and…

Reconciling symbolic and distributed representations is a crucial challenge that can potentially resolve the limitations of current deep learning. Remarkable advances in this direction have been achieved recently via generative…

Machine Learning · Computer Science 2021-02-09 Jindong Jiang , Sungjin Ahn