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Sophisticated analysis of modern large-scale structure surveys requires mock catalogs. Mock catalogs are used to optimize survey design, test reduction and analysis pipelines, make theoretical predictions for basic observables and propagate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Martin White , Jeremy L Tinker , Cameron K McBride

Fast k-Nearest Neighbor search over real-valued vector spaces (KNN) is an important algorithmic task for information retrieval and recommendation systems. We present a method for using reduced precision to represent vectors through…

Information Retrieval · Computer Science 2021-10-19 Anthony Ko , Iman Keivanloo , Vihan Lakshman , Eric Schkufza

We use the results of previous work building a halo model formalism for the distribution of neutral hydrogen, along with experimental parameters of future radio facilities, to place forecasts on astrophysical and cosmological parameters…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-20 Hamsa Padmanabhan , Alexandre Refregier , Adam Amara

The circum-galactic medium (CGM) can feasibly be mapped by multiwavelength surveys covering broad swaths of the sky. With multiple large datasets becoming available in the near future, we develop a likelihood-free Deep Learning technique…

We present a detailed description and validation of our massively-parallel update to the mass-Peak Patch method, a fully predictive initial-space algorithm to quickly generate dark matter halo catalogues in very large cosmological volumes.…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 George Stein , Marcelo A. Alvarez , J. Richard Bond

We propose a novel approach using neural networks (NNs) to differentiate between cosmological models, and implemented LIME as an interpretability approach to identify the key features influencing our model's decisions. We show the potential…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-03 Indira Ocampo , George Alestas , Savvas Nesseris , Domenico Sapone

The $k$-Nearest Neighbour Cumulative Distribution Functions are measures of clustering for discrete datasets that are fast and efficient to compute. They are significantly more informative than the 2-point correlation function. Their…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-27 Kwanit Gangopadhyay , Arka Banerjee , Tom Abel

Studies of galaxy clusters have proved crucial in helping to establish the standard model of cosmology, with a universe dominated by dark matter and dark energy. A theoretical basis that describes clusters as massive, multi-component,…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-26 Steven W. Allen , August E. Evrard , Adam B. Mantz

The k-nearest neighbors (k-NN) is a basic machine learning (ML) algorithm, and several quantum versions of it, employing different distance metrics, have been presented in the last few years. Although the Euclidean distance is one of the…

Emerging Technologies · Computer Science 2024-04-25 Enrico Zardini , Enrico Blanzieri , Davide Pastorello

Cosmological neutral hydrogen (HI) surveys provide a promising tomographic probe of the post-reionization era and of the standard model of cosmology. Simulations of this signal are crucial for maximizing the utility of these surveys. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-09 Pascal Hitz , Pascale Berner , Devin Crichton , John Hennig , Alexandre Refregier

We investigate 3D density and weak lensing profiles of dark matter haloes predicted by a cosmology-rescaling algorithm for $N$-body simulations. We extend the rescaling method of Angulo & White (2010) and Angulo & Hilbert (2015) to improve…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Malin Renneby , Stefan Hilbert , Raúl E. Angulo

Cosmography, as an integral branch of cosmology, strives to characterize the Universe without relying on pre-determined cosmological models. This model-independent approach utilizes Taylor series expansions around the current epoch,…

General Physics · Physics 2024-06-11 Seokcheon Lee

We train three convolutional neural networks (CNNs) to classify galaxies with Galaxy Zoo 2 dataset and extract the activations from the last fully connected layer or the last average pooling layer of CNNs to study the high-dimensional…

Astrophysics of Galaxies · Physics 2018-07-17 Jia-Ming Dai , Jizhou Tong

Deep learning models have been shown to outperform methods that rely on summary statistics, like the power spectrum, in extracting information from complex cosmological data sets. However, due to differences in the subgrid physics…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-16 Andrea Roncoli , Aleksandra Ćiprijanović , Maggie Voetberg , Francisco Villaescusa-Navarro , Brian Nord

Inferring the values and uncertainties of cosmological parameters in a cosmology model is of paramount importance for modern cosmic observations. In this paper, we use the simulation-based inference (SBI) approach to estimate cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-02 Moonzarin Reza , Yuanyuan Zhang , Brian Nord , Jason Poh , Aleksandra Ciprijanovic , Louis Strigari

We present a fast Markov Chain Monte-Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent CMB experiments and provide parameter constraints, including sigma_8, from the CMB independent of…

Astrophysics · Physics 2008-11-26 Antony Lewis , Sarah Bridle

Using cosmological dark matter only simulations of a $(1.6$ Gpc$/h)^3$ volume from the Legacy simulation project, we calculate Cosmic Mach Numbers (CMN) and perform a theoretical investigation of their relation with halo properties and…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-09 Romain Meriot , Sadegh Khochfar , Jose Onorbe , Britton Smith

A promising method for measuring the cosmological parameter combination fsigma_8 is to compare observed peculiar velocities with peculiar velocities predicted from a galaxy density field using perturbation theory. We use N-body simulations…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Amber M. Hollinger , Michael J. Hudson

Reconstructing the initial conditions of the Universe from late-time observations has the potential to optimally extract cosmological information. Due to the high dimensionality of the parameter space, a differentiable forward model is…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-19 Adrian E. Bayer , Chirag Modi , Simone Ferraro

In this work, we explore new constraints on phantom scalar field cosmologies with a scalar field employing early times catalogues related to CMB measurements, along with the local standard observables, like Supernovae Type Ia (SNIa), $H(z)$…

General Relativity and Quantum Cosmology · Physics 2024-05-27 José Antonio Nájera , Celia Escamilla-Rivera