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Aims. We present an innovative artificial neural network (ANN) architecture, called Generative ANN (GANN), that computes the forward model, that is it learns the function that relates the unknown outputs (stellar atmospheric parameters, in…

Instrumentation and Methods for Astrophysics · Physics 2016-10-19 C. Dafonte , D. Fustes , M. Manteiga , D. Garabato , M. A. Alvarez , A. Ulla , C. Allende Prieto

There is growing interest in using 3-dimensional neutral hydrogen mapping with the redshifted 21 cm line as a cosmological probe, as it has been argued to have a greater long-term potential than the cosmic microwave background. However, its…

Astrophysics · Physics 2008-11-26 Yi Mao , Max Tegmark , Matthew McQuinn , Matias Zaldarriaga , Oliver Zahn

We present a coherent, re-usable python framework which further builds on the cosmological emulator code CosmoPower. In the current era of high-precision cosmology, we require high-accuracy calculations of cosmological observables with…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 H. T. Jense , I. Harrison , E. Calabrese , A. Spurio Mancini , B. Bolliet , J. Dunkley , J. C. Hill

In this work, we achieve the determination of the cosmic curvature $\Omega_K$ in a cosmological model-independent way, by using the Hubble parameter measurements $H(z)$ and type Ia supernovae (SNe Ia). In our analysis, two nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-26 Guo-Jian Wang , Xiao-Jiao Ma , Jun-Qing Xia

Forthcoming cosmic microwave background experiments (CMB) will provide precise new tests of structure-formation theories. The geometry of the Universe may be determined robustly, and the classical cosmological parameters, such as the…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

The interpretation of observations of atomic and molecular tracers in the galactic and extragalactic interstellar medium (ISM) requires comparisons with state-of-the-art astrophysical models to infer some physical conditions. Usually, ISM…

I outline a method for estimating astrophysical parameters (APs) from multidimensional data. It is a supervised method based on matching observed data (e.g. a spectrum) to a grid of pre-labelled templates. However, unlike standard machine…

Astrophysics · Physics 2007-11-29 C. A. L. Bailer-Jones

With the increasing use of nonlinear devices in both generation and consumption of power, it is essential that we develop accurate and quick control for active filters to suppress harmonics. Time delays between input and output are…

Systems and Control · Electrical Eng. & Systems 2024-10-04 Dixant Bikal Sapkota , Puskar Neupane , Kajal Pokharel , Shahabuddin Khan

We present a method for ultra-fast confrontation of the WMAP cosmic microwave background observations with theoretical models, implemented as a publicly available software package called CMBfit, useful for anyone wishing to measure…

Astrophysics · Physics 2013-08-07 Havard B. Sandvik , Max Tegmark , Xiaomin Wang , Matias Zaldarriaga

We propose a machine learning approach to the blind detection of extragalactic point sources on maps of the temperature anisotropies of the cosmic microwave background. Using realistic simulations of the microwave sky as seen by Planck, we…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-01 P. Diego-Palazuelos , R. B. Barreiro , P. Vielva , D. Balbás , M. López-Caniego , D. Herranz , B. Casaponsa

Conventional predictive Artificial Neural Networks (ANNs) commonly employ deterministic weight matrices; therefore, their prediction is a point estimate. Such a deterministic nature in ANNs causes the limitations of using ANNs for medical…

Machine Learning · Computer Science 2020-07-02 Minhyeok Lee , Junhee Seok

Modelling the complex physics of the Interstellar Medium (ISM) in the context of large-scale numerical simulations is a challenging task. A number of methods have been proposed to embed a description of the ISM into different codes. We…

Instrumentation and Methods for Astrophysics · Physics 2011-03-03 T. Grassi , E. Merlin , L. Piovan , U. Buonomo , C. Chiosi

Deep learning is a powerful analysis technique that has recently been proposed as a method to constrain cosmological parameters from weak lensing mass maps. Due to its ability to learn relevant features from the data, it is able to extract…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-26 Janis Fluri , Tomasz Kacprzak , Aurelien Lucchi , Alexandre Refregier , Adam Amara , Thomas Hofmann

The cosmic microwave background (CMB), carrying the inhomogeneous information of the very early universe, is of great significance for understanding the origin and evolution of our universe. However, observational CMB maps contain serious…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-12 Guo-Jian Wang , Hong-Liang Shi , Ye-Peng Yan , Jun-Qing Xia , Yan-Yun Zhao , Si-Yu Li , Jun-Feng Li

Breakdown of rotational invariance of the primordial power spectrum manifests in the statistical anisotropy of the observed Cosmic Microwave Background (CMB) radiation. Hemispherical power asymmetry in the CMB may be caused due to a dipolar…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-23 Md Ishaque Khan , Rajib Saha

We study the benefits and limits of parallelised Markov chain Monte Carlo (MCMC) sampling in cosmology. MCMC methods are widely used for the estimation of cosmological parameters from a given set of observations and are typically based on…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-03 Joël Akeret , Sebastian Seehars , Adam Amara , Alexandre Refregier , André Csillaghy

Existing adaptive bias techniques, which seek to estimate free energies and physical properties from molecular simulations, are limited by their reliance on fixed kernels or basis sets which hinder their ability to efficiently conform to…

Statistical Mechanics · Physics 2018-04-04 Hythem Sidky , Jonathan K. Whitmer

In this work, we propose a new nonparametric approach for reconstructing a function from observational data using an Artificial Neural Network (ANN), which has no assumptions about the data and is a completely data-driven approach. We test…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-26 Guo-Jian Wang , Xiao-Jiao Ma , Si-Yao Li , Jun-Qing Xia

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

We use the emulation framework CosmoPower to construct and publicly release neural network emulators of cosmological observables, including the Cosmic Microwave Background (CMB) temperature and polarization power spectra, matter power…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-06 Boris Bolliet , Alessio Spurio Mancini , J. Colin Hill , Mathew Madhavacheril , Hidde T. Jense , Erminia Calabrese , Jo Dunkley