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Related papers: What can we learn about Reionization astrophysical…

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We study the reionization history of the Universe in cosmological models with non-Gaussian density fluctuations, taking them to have a renormalized $\chi^2$ probability distribution function parametrized by the number of degrees of freedom,…

Astrophysics · Physics 2009-11-11 Pedro P. Avelino , Andrew R. Liddle

A common task is the determination of system parameters from spectroscopy, where one compares the experimental spectrum with calculated spectra, that depend on the desired parameters. Here we discuss an approach based on a machine learning…

Quantum Physics · Physics 2022-05-04 Farhad Taher-Ghahramani , Fulu Zheng , Alexander Eisfeld

We present a semi-analytic model for the thermal and ionization history of the universe at 1000 >~ z >~ 3. This model incorporates much of the essential physics included in full-scale hydrodynamical simulations, such as (1) gravitational…

Astrophysics · Physics 2009-10-31 Weihsueh A. Chiu , Jeremiah P. Ostriker

The next generation 21 cm surveys open a new window onto the early stages of cosmic structure formation and provide new insights about the Epoch of Reionization (EoR). However, the non-Gaussian nature of the 21 cm signal along with the huge…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-18 Héctor J. Hortúa , Luigi Malago , Riccardo Volpi

Improvements in current instruments and the advent of next-generation instruments will soon push observational 21 cm cosmology into a new era, with high significance measurements of both the power spectrum and the mean ("global") signal of…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-08 Adrian Liu , Aaron R. Parsons

Time-domain observations are increasingly important in astronomy, and are often the only way to study certain objects. The volume of time-series data is increasing dramatically as new surveys come online - for example, the Vera Rubin…

Instrumentation and Methods for Astrophysics · Physics 2023-08-02 P. Scicluna , S. Waterval , D. A. Vasquez-Torres , S. Srinivasan , S. Jamal

We formulate a reduced-order strategy for efficiently forecasting complex high-dimensional dynamical systems entirely based on data streams. The first step of our method involves reconstructing the dynamics in a reduced-order subspace of…

Data Analysis, Statistics and Probability · Physics 2017-03-08 Zhong Yi Wan , Themistoklis P. Sapsis

During the Epoch of reionisation, the intergalactic medium is reionised by the UV radiation from the first generation of stars and galaxies. One tracer of the process is the 21 cm line of hydrogen that will be observed by the Square…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-29 Julien Hiegel , Emilie Thélie , Dominique Aubert , Jonathan Chardin , Nicolas Gillet , Pierre Galois , Nicolas Mai , Pierre Ocvirk , Rodrigo Ibata

We highlight recent progress in the sophistication and diversification of cosmic dawn and reionization simulations. The application of these modeling tools to current observations has allowed us narrow down the timing of reionization, which…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-22 Andrei Mesinger

The 21 cm signal contains a wealth of information about the formation of the first stars and the reionization of the intergalactic medium during the Cosmic Dawn (CD) and Epoch of Reionization (EoR). The timing of these important milestones…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-15 Nadia Cooper , Carina Norregaard , Romain Meriot , Jonathan R. Pritchard

Gaussian processes are a fully Bayesian smoothing technique that allows for the reconstruction of a function and its derivatives directly from observational data, without assuming a specific model or choosing a parameterization. This is…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-27 Marina Seikel , Chris Clarkson

We apply for the first time Gaussian Process Regression (GPR) as a foreground removal technique in the context of single-dish, low redshift HI intensity mapping, and present an open-source Python toolkit for doing so. We use MeerKAT and…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-05 Paula S. Soares , Catherine A. Watkinson , Steven Cunnington , Alkistis Pourtsidou

The 21 cm signal from the Epoch of Reionization should be observed within the next decade. While a simple statistical detection is expected with SKA pathfinders, the SKA will hopefully produce a full 3D mapping of the signal. To extract…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-28 Hayato Shimabukuro , Benoit Semelin

We present a survey strategy to detect the neutral hydrogen (HI) power spectrum at $5<z<6$ using the SKA-Low radio telescope in presence of foregrounds and instrumental effects. We simulate observations of the inherently weak HI signal…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-27 Zhaoting Chen , Emma Chapman , Laura Wolz , Aishrila Mazumder

Recent work has shown that modified gravitational wave (GW) propagation can be a powerful probe of dark energy and modified gravity, specific to GW observations. We use the technique of Gaussian processes, that allows the reconstruction of…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-11 Enis Belgacem , Stefano Foffa , Michele Maggiore , Tao Yang

Gaussian process regression (GPR) is a fundamental model used in machine learning. Owing to its accurate prediction with uncertainty and versatility in handling various data structures via kernels, GPR has been successfully used in various…

Machine Learning · Computer Science 2021-12-16 Yuya Yoshikawa , Tomoharu Iwata

The current accelerated expansion of the Universe remains ones of the most intriguing topics in modern cosmology, driving the search for innovative statistical techniques. Recent advancements in machine learning have significantly enhanced…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-03 José de Jesús Velázquez , Luis A. Escamilla , Purba Mukherjee , J. Alberto Vázquez

In this study, we introduce a novel analytical Gaussian Process (GP) cosmography methodology, leveraging the differentiable properties of GPs to derive key cosmological quantities analytically. Our approach combines cosmic chronometer (CC)…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-19 Bikash R. Dinda

Systematic effects that limit the achievable sensitivity of current low-frequency radio telescopes to the 21 cm signal are among the foremost challenges in observational 21 cm cosmology. The standard approach to retrieving the 21 cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 S. Munshi , L. V. E. Koopmans , F. G. Mertens , A. R. Offringa , S. A. Brackenhoff , E. Ceccotti , J. K. Chege , L. Y. Gao , S. Ghosh , M. Mevius , S. Zaroubi

A number of radio interferometers are currently being planned or constructed to observe 21 cm emission from reionization. Not only will such measurements provide a detailed view of that epoch, but, since the 21 cm emission also traces the…