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A standard parametric maximum-likelihood technique is used to determine both the probability distribution over total HI mass $M_{\rm HI}$ and the regression of this quantity on the linear optical diameter $D_{\rm o}$ for field giant spirals…

Astrophysics · Physics 2009-10-28 José M. Solanes , Riccardo Giovanelli , Martha P. Haynes

Cosmological measurements of the 21-cm line of neutral hydrogen are poised to dramatically enhance our understanding of the early universe. In particular, both the epochs of reionization and cosmic dawn remain largely uncharted, and the…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-13 Julian B. Muñoz , Francis-Yan Cyr-Racine

Most parameter constraints obtained from cosmic microwave background (CMB) anisotropy data are based on power estimates and rely on approximate likelihood functions; computational difficulties generally preclude an exact analysis based on…

Astrophysics · Physics 2009-11-06 M. Douspis , J. G. Bartlett , A. Blanchard , M. Le Dour

Likelihood analysis is typically limited to normally distributed noise due to the difficulty of determining the probability density function of complex, high-dimensional, non-Gaussian, and anisotropic noise. This is a major limitation for…

Instrumentation and Methods for Astrophysics · Physics 2023-06-14 Ronan Legin , Alexandre Adam , Yashar Hezaveh , Laurence Perreault Levasseur

Simulation-based inference (SBI) is emerging as a new statistical paradigm for addressing complex scientific inference problems. By leveraging the representational power of deep neural networks, SBI can extract the most informative…

Instrumentation and Methods for Astrophysics · Physics 2025-10-17 Huifang Lyu , James Alvey , Noemi Anau Montel , Mauro Pieroni , Christoph Weniger

We develop a Bayesian hierarchical modelling approach for cosmic shear power spectrum inference, jointly sampling from the posterior distribution of the cosmic shear field and its (tomographic) power spectra. Inference of the shear power…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-11 Justin Alsing , Alan Heavens , Andrew H. Jaffe , Alina Kiessling , Benjamin Wandelt , Till Hoffmann

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

Preparing for the first detection of the cosmic 21-cm signal from large-scale interferometer experiments requires rigorous testing of the data analysis and reduction pipelines. To validate that these pipelines do not erroneously remove or…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-14 Bradley Greig , J. Stuart B. Wyithe , Steven G. Murray , Simon J. Mutch , Cathryn M. Trott

We forecast astrophysical and cosmological parameter constraints from synergies between 21 cm intensity mapping and wide field optical galaxy surveys (both spectroscopic and photometric) over $z \sim 0-3$. We focus on the following survey…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-27 Hamsa Padmanabhan , Alexandre Refregier , Adam Amara

Neural networks are being extensively used for modelling data, especially in the case where no likelihood can be formulated. Although in the case of X-ray spectral fitting, the likelihood is known, we aim to investigate the neural networks…

Instrumentation and Methods for Astrophysics · Physics 2024-02-22 Didier Barret , Simon Dupourqué

Cross-correlating neutral hydrogen (HI) 21cm intensity mapping with galaxy surveys provides an effective probe of astrophysical and cosmological information. This work presents a cross-correlation analysis between MeerKAT single-dish HI…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-12 Yu-Er Jiang , Yan Gong , Qi Xiong , Wenxiang Pei , Yun Liu , Furen Deng , Zi-yan Yuwen , Meng Zhang , Xingchen Zhou , Xuelei Chen , Yin-Zhe Ma , Qi Guo , Bin Yue

The redshifted 21\,cm line is an emerging tool in observational cosmology that can serve as a direct probe of the intergalactic medium throughout the cosmic timeline. However, the observation of the cosmological 21\,cm signal from early…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-12 Samit Kumar Pal , Abhirup Datta , Aishrila Mazumder , Anshuman Tripathi

A major challenge in extracting information from current and upcoming surveys of cosmological Large-Scale Structure (LSS) is the limited availability of computationally expensive high-fidelity simulations. We introduce calibrated Neural…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-24 He Jia

Microwave background temperature and polarization observations are a powerful way to constrain cosmological parameters if the likelihood function can be calculated accurately. The temperature and polarization fields are correlated, partial…

Astrophysics · Physics 2012-04-25 Samira Hamimeche , Antony Lewis

Accurate and precise covariance matrices will be important in enabling planned cosmological surveys to detect new physics. Standard methods imply either the need for many N-body simulations in order to obtain an accurate estimate, or a…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-13 Alex Hall , Andy Taylor

We study the cosmological power spectra (PS) of the differential and integral galaxy volume number densities $\gamma_i$ and $\gamma_i^{*}$, constructed with the cosmological distances $d_i$ $(i=A,G,L,Z)$, where $d_A$ is the angular diameter…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-23 Amanda R. Lopes , Marcelo B. Ribeiro , William R. Stoeger

Cross-correlations between 21cm observations and galaxy surveys provide a powerful probe of reionization by reducing foreground sensitivity while linking ionization morphology to galaxies. We quantify the constraining power of 21cm-Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Yannic Pietschke , Anne Hutter , Caroline Heneka

By opening up new avenues to statistically constrain astrophysics and cosmology with large-scale structure observations, the line intensity mapping (LIM) technique calls for novel tools for efficient forward modeling and inference. Implicit…

Simulation-Based Inference (SBI) is a promising Bayesian inference framework that alleviates the need for analytic likelihoods to estimate posterior distributions. Recent advances using neural density estimators in SBI algorithms have…

Instrumentation and Methods for Astrophysics · Physics 2022-07-13 Justine Zeghal , François Lanusse , Alexandre Boucaud , Benjamin Remy , Eric Aubourg

We discuss the problem of constraining cosmological parameters with cosmic microwave background band--power estimates. Because these latter are variances, they do not have gaussian distribution functions and, hence, the standard…

Astrophysics · Physics 2007-05-23 J. G. Bartlett , A. Blanchard , M. Douspis , M. Le Dour
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