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We demonstrate a GPU-accelerated nested sampling framework for efficient high-dimensional Bayesian inference in cosmology. Using JAX-based neural emulators and likelihoods for cosmic microwave background and cosmic shear analyses, our…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-08 Toby Lovick , David Yallup , Davide Piras , Alessio Spurio Mancini , Will Handley

The HI 21cm absorption line is masked by bright foregrounds and systematic distortions that arise due to the chromaticity of the antenna used to make the observation coupling to the spectral inhomogeneity of these foregrounds. We…

Instrumentation and Methods for Astrophysics · Physics 2021-11-12 Dominic Anstey , Eloy de Lera Acedo , Will Handley

Measurement of the global 21-cm signal during Cosmic Dawn (CD) and the Epoch of Reionization (EoR) is made difficult by bright foreground emission which is 2-5 orders of magnitude larger than the expected signal. Fitting for a…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-20 Michael Pagano , Peter Sims , Adrian Liu , Dominic Anstey , Will Handley , Eloy De Lera Acedo

Global 21cm cosmology aims to investigate the cosmic dawn and epoch of reionisation by measuring the sky averaged HI absorption signal, which requires, accurate modelling of, or correction for, the bright radio foregrounds and distortions…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Dominic Anstey , Eloy de Lera Acedo , Will Handley

We advocate for a new paradigm of cosmological likelihood-based inference, leveraging recent developments in machine learning and its underlying technology, to accelerate Bayesian inference in high-dimensional settings. Specifically, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-06 Davide Piras , Alicja Polanska , Alessio Spurio Mancini , Matthew A. Price , Jason D. McEwen

This study presents a reconstruction of the Gaussian Beam Tracing solution using CUDA, with a particular focus on the utilisation of GPU acceleration as a means of overcoming the performance limitations of traditional CPU algorithms in…

Performance · Computer Science 2025-01-24 Zhang Sheng , Lishu Duan , Hanbo Jiang

Direct detection of the Epoch of Reionization via the redshifted 21-cm line will have unprecedented implications on the study of structure formation in the early Universe. To fulfill this promise current and future 21-cm experiments will…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-22 F. Mertens , A. Ghosh , L. V. E. Koopmans

Detecting and characterizing the Epoch of Reionization and Cosmic Dawn via the redshifted 21-cm hyperfine line of neutral hydrogen will revolutionize the study of the formation of the first stars, galaxies, black holes and intergalactic gas…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 F. G. Mertens , A. Ghosh , L. V. E. Koopmans

The cosmological global (sky-averaged) 21-cm signal is a powerful tool to probe the evolution of the intergalactic medium (IGM) in high-redshift Universe ($z \leq 6$). One of the biggest observational challenges is to remove the foreground…

Instrumentation and Methods for Astrophysics · Physics 2018-11-14 Bang D. Nhan , Richard F. Bradley , Jack O. Burns

The 21-cm global signal is obscured by very bright galactic and extra galactic foreground emissions. Typical single-spectrum fit (SSF) based methods for foreground/signal separation can result in biased estimates of the cosmological signal…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-27 Yordan D. Ignatov , Jonathan R. Pritchard

The precise form of the foregrounds for sky-averaged measurements of the 21-cm line during and before the epoch of reionization is unknown. We suggest that the level of complexity in the foreground models used to fit global 21-cm data…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-26 Geraint Harker

We present the completion of a data analysis pipeline that self-consistently separates global 21-cm signals from large systematics using a pattern recognition technique. In the first paper of this series, we obtain optimal basis vectors…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-22 David Rapetti , Keith Tauscher , Jordan Mirocha , Jack O. Burns

With large-scale Integral Field Spectroscopy (IFS) surveys of thousands of galaxies currently under-way or planned, the astronomical community is in need of methods, techniques and tools that will allow the analysis of huge amounts of data.…

Instrumentation and Methods for Astrophysics · Physics 2015-12-22 Georgios Bekiaris , Karl Glazebrook , Christopher J. Fluke , Roberto Abraham

We present an investigation of the horizon and its effect on global 21-cm observations and analysis. We find that the horizon cannot be ignored when modeling low frequency observations. Even if the sky and antenna beam are known exactly,…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-15 Neil Bassett , David Rapetti , Keith Tauscher , Bang D. Nhan , David D. Bordenave , Joshua J. Hibbard , Jack O. Burns

Inferring parameters and testing hypotheses from gravitational wave signals is a computationally intensive task central to modern astrophysics. Nested sampling, a Bayesian inference technique, has become an established standard for this in…

Instrumentation and Methods for Astrophysics · Physics 2025-09-30 David Yallup , Metha Prathaban , James Alvey , Will Handley

Considerable observational efforts are being dedicated to measuring the sky-averaged (global) 21-cm signal of neutral hydrogen from Cosmic Dawn and the Epoch of Reionization. Deriving observational constraints on the astrophysics of this…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-18 Christian H. Bye , Stephen K. N. Portillo , Anastasia Fialkov

Structural parameters are normally extracted from observed galaxies by fitting analytic light profiles to the observations. Obtaining accurate fits to high-resolution images is a computationally expensive task, requiring many model…

Instrumentation and Methods for Astrophysics · Physics 2015-03-17 Benjamin R. Barsdell , David G. Barnes , Christopher J. Fluke

21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizing this promise will require the extraction of a…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-02 Adrian Liu , Max Tegmark

In a sky-averaged 21-cm signal experiment, the uncertainty on the extracted signal depends mainly on the covariance between the foreground and 21-cm signal models. In this paper, we construct these models using the modes of variation…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-19 Anchal Saxena , P. Daniel Meerburg , Eloy de Lera Acedo , Will Handley , Léon V. E. Koopmans

Detecting the global 21 cm signal from the epoch of reionization remains a major observational challenge due to bright foregrounds and instrumental systematics. As part of the Colombian Antarctic Telescopes for 21 cm Absorption during…

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