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Recent Lyman-$\alpha$ forest tomography measurements of the intergalactic medium (IGM) have revealed a wealth of cosmic structures at high redshift ($z\sim 2.5$). In this work, we present the Tomographic Absorption Reconstruction and…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-18 Benjamin Horowitz , Khee-Gan Lee , Martin White , Alex Krolewski , Metin Ata

Observations of redshifted Lyman alpha forest absorption in the spectra of quasistellar objects (QSOs) provide a highly sensitive probe of the distribution of gaseous matter in the universe. Over the past two decades optical spectroscopy…

Astrophysics · Physics 2009-10-30 Michael Rauch

We propose a semismooth Newton-based augmented Lagrangian framework for reconstructing sparse sources in inverse acoustic scattering problems. Rather than working in the unknown source space, our semismooth Newton updates operate in the…

Numerical Analysis · Mathematics 2025-10-29 Nirui Tan , Hongpeng Sun

The intense radiation emitted by luminous quasars dramatically alters the ionization state of their surrounding IGM. This so-called proximity effect extends out to tens of Mpc, and manifests as large coherent regions of enhanced…

Astrophysics of Galaxies · Physics 2019-09-25 Tobias M. Schmidt , Joseph F. Hennawi , Khee-Gan Lee , Zarija Lukic , Jose Onorbe , Martin White

We develop a field-level posterior for cosmological data by marginalizing over initial conditions and noise in a general forward model. While our focus is on large-scale structure data, the results generalize to any weakly non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-29 Massimo Pietroni , Fabian Schmidt

Our goal in this paper is to test some popular dark matter models by Ly-alpha forest in QSO spectra. Recent observations of the size and velocity of Ly-alpha forest clouds have indicated that the Ly-alpha absorption is probably not given by…

Astrophysics · Physics 2009-10-28 Hongguang BI , Jian GE , Li-Zhi FANG

These lecture notes delve into field-level inference, a framework offering a robust way to extract more information and avoid biases compared to traditional methods for cosmological data analysis. The core idea is to analyse uncompressed…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-18 Florent Leclercq

We present results from end-to-end simulations of observations designed to constrain the rate of change in the expansion history of the Universe using the redshift drift of the Lyman-$\alpha$ forest absorption lines along the lines-of-sight…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-19 Chenxing Dong , Anthony Gonzalez , Stephen Eikenberry , Sarik Jeram , Manunya Likamonsavad , Jochen Liske , Deno Stelter , Amanda Townsend

Field-level inference has emerged as a promising framework to fully harness the cosmological information encoded in next-generation galaxy surveys. It involves performing Bayesian inference to jointly estimate the cosmological parameters…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-19 Hugo Simon , François Lanusse , Arnaud de Mattia

We present a novel, fast method to recover the density field through the statistics of the transmitted flux in high redshift quasar absorption spectra. The proposed technique requires the computation of the probability distribution function…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Simona Gallerani , Francisco-Shu Kitaura , Andrea Ferrara

In many real-world scenarios, such as gas leak detection or environmental pollutant tracking, solving the Inverse Source Localization and Characterization problem involves navigating complex, dynamic fields with sparse and noisy…

Machine Learning · Computer Science 2025-01-23 Yiwei Shi , Mengyue Yang , Qi Zhang , Weinan Zhang , Cunjia Liu , Weiru Liu

Massive spectroscopic surveys of high-redshift quasars yield large numbers of correlated Lyman {\alpha} absorption spectra that can be used to measure large-scale structure. Simulations of these surveys are required to accurately interpret…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Andreu Font-Ribera , Patrick McDonald , Jordi Miralda-Escudé

We present an improved analytical model to predict the Lyman-alpha forest at the field level in redshift space from the dark matter field, expanding upon the widely-used Fluctuating Gunn-Peterson approximation (FGPA). In particular, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-25 Francesco Sinigaglia , Francisco-Shu Kitaura , Kentaro Nagamine , Yuri Oku , Andrés Balaguera-Antolínez

We use LUQAS, a sample of 27 high resolution high signal-to-noise UVES quasar (QSO) spectra (Kim et al. 2004), and the Croft et al. (2002) sample together with a set of high resolution large box size hydro-dynamical simulations run with the…

Astrophysics · Physics 2009-11-11 Matteo Viel

The comparison of quasar absorption spectra with numerically simulated spectra from hierarchical cosmological models of structure formation promises to be a valuable tool to discriminate among these models. We present simulation results for…

Astrophysics · Physics 2009-10-31 M. Machacek , G. Bryan , P. Anninos , A. Meiksin , M. L. Norman , Y. Zhang

The Lyman-$\alpha$ forest offers a unique avenue for studying the distribution of matter in the high redshift universe and extracting precise constraints on the nature of dark matter, neutrino masses, and other $\Lambda$CDM extensions.…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-29 Laura Cabayol-Garcia , Jonás Chaves-Montero , Andreu Font-Ribera , Christian Pedersen

Accurate analyses of present and next-generation galaxy surveys require new ways to handle effects of non-linear gravitational structure formation in data. To address these needs we present an extension of our previously developed algorithm…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-15 Jens Jasche , Guilhem Lavaux

We study the mapping from Lagrangian to Eulerian space in the context of the Effective Field Theory (EFT) of Large Scale Structure. We compute Lagrangian displacements with Lagrangian Perturbation Theory (LPT) and perform the full…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-16 Tobias Baldauf , Emmanuel Schaan , Matias Zaldarriaga

Deep learning (DL) has been shown to outperform traditional, human-defined summary statistics of the Ly{\alpha} forest in constraining key astrophysical and cosmological parameters owing to its ability to tap into the realm of non-Gaussian…

Instrumentation and Methods for Astrophysics · Physics 2025-10-24 Parth Nayak , Michael Walther , Daniel Gruen

This paper proposes a novel algorithm for image phase retrieval, i.e., for recovering complex-valued images from the amplitudes of noisy linear combinations (often the Fourier transform) of the sought complex images. The algorithm is…

Signal Processing · Electrical Eng. & Systems 2018-10-19 Joshin P. Krishnan , José M. Bioucas-Dias , Vladimir Katkovnik