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We investigate the possibility of using the cross-correlation of the Lyman-alpha forest and redshifted 21-cm emission to detect the baryon acoustic oscillation (BAO). The standard Fisher matrix formalism is used to determine the accuracy…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-13 Tapomoy Guha Sarkar , Somnath Bharadwaj

We present the first simulation of the signature of baryonic acoustic oscillations (BAO) in Lyman alpha forest data containing 180,000 mock quasar sight-lines. We use eight large dark-matter only simulations onto which we paint the Lyman…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-09 Anže Slosar , Shirley Ho , Martin White , Thibaut Louis

We present 40 fully hydrodynamical numerical simulations of the intergalactic gas that gives rise to the Ly-alpha forest. We make artificial spectra from each and measure three output parameters: the mean flux, a measure of the most common…

Accurate estimation of forest biomass is crucial for monitoring carbon sequestration and informing climate change mitigation strategies. Existing methods often rely on allometric models, which estimate individual tree biomass by relating it…

Machine Learning · Computer Science 2026-03-06 Habib Pourdelan , Zhengkang Xiang , Hugh Stewart , Cam Nicholson , Martin Tomko , Kourosh Khoshelham

I apply the well controlled Hydro-PM approximation of Gnedin & Hui to model the column density distribution of the Lyman-alpha forest for 25 different flat cosmological scenarios, including variants of the standard CDM, tilted CDM, CDM with…

Astrophysics · Physics 2009-10-30 Nickolay Y. Gnedin

Obtaining accurate photometric redshift estimations is an important aspect of cosmology, remaining a prerequisite of many analyses. In creating novel methods to produce redshift estimations, there has been a shift towards using machine…

Instrumentation and Methods for Astrophysics · Physics 2021-07-07 Ben Henghes , Connor Pettitt , Jeyan Thiyagalingam , Tony Hey , Ofer Lahav

The low-redshift evolution of the intergalactic medium is investigated using hydrodynamic cosmological simulations. The assumed cosmological model is a critical density cold dark matter universe. The imposed uniform background of ionizing…

Astrophysics · Physics 2009-10-30 T. Theuns , A. Leonard , G. Efstathiou

We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body…

Astrophysics · Physics 2008-02-03 David H. Weinberg , Neal Katz , Lars Hernquist

Detecting multiple structural breaks in high-dimensional data remains a challenge, particularly when changes occur in higher-order moments or within complex manifold structures. In this paper, we propose REAMP (Resonance-Enhanced Analysis…

Methodology · Statistics 2026-01-14 Xiaoping Shi , Baisuo Jin , Xianhui Liu , Qiong Li

The hyperfine structure absorption lines of neutral hydrogen in spectra of high-redshift radio sources, known collectively as the 21-cm forest, have been demonstrated as a sensitive probe to the small-scale structures governed by the dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Tian-Yang Sun , Yue Shao , Yichao Li , Yidong Xu , He Wang , Xin Zhang

We present a set of ultra-large particle-mesh simulations of the LyA forest targeted at understanding the imprint of baryon acoustic oscillations (BAO) in the inter-galactic medium. We use 9 dark matter only simulations which can, for the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Martin White , Adrian Pope , Jordan Carlson , Katrin Heitmann , Salman Habib , Patricia Fasel , David Daniel , Zarija Lukic

We present the Lyman-$\alpha$ flux power spectrum measurements of the XQ-100 sample of quasar spectra obtained in the context of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the…

We describe techniques for comparing spectra extracted from cosmological simulations and observational data, using the same methodology to link Lyman-alpha properties derived from the simulations with properties derived from observational…

Astrophysics · Physics 2009-11-07 C. E. Petry , C. D. Impey , N. Katz , D. H. Weinberg , L. E. Hernquist

We review recent developments in the theory of the Lyman-alpha forest and their implications for the role of the forest as a test of cosmological models. Simulations predict a relatively tight correlation between the local Lya optical depth…

Astrophysics · Physics 2009-11-07 David H. Weinberg , Romeel Dav'e , Neal Katz , Juna A. Kollmeier

We propose a computationally efficient algorithm for gradient-based linear dimension reduction and high-dimensional regression. The algorithm initially computes a Mondrian forest and uses this estimator to identify a relevant feature…

Statistics Theory · Mathematics 2024-07-16 Ricardo Baptista , Eliza O'Reilly , Yangxinyu Xie

Accurate LiDAR simulation is crucial for autonomous driving, especially under adverse weather conditions. Existing methods struggle to capture the complex interactions between LiDAR signals and atmospheric phenomena, leading to unrealistic…

Robotics · Computer Science 2026-04-03 Vivek Anand , Bharat Lohani , Rakesh Mishra , Gaurav Pandey

We describe large scale structure at high redshift in terms of the Cosmic Web picture for {S,Lambda,O,H}CDM models: how galactic-scale ``peak-patches'', filaments and membranes create an interconnected intergalactic medium. The ideas are…

Astrophysics · Physics 2007-05-23 J. Richard Bond , James W. Wadsley

The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light…

Lyman-alpha forest data probing the post-reionization Universe shows surprisingly large opacity fluctuations over rather large ($\ge$50 comoving Mpc/h) spatial scales. We model these fluctuations using a hybrid approach utilizing the large…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-21 Jonathan Chardin , Ewald Puchwein , Martin G. Haehnelt

In this work we expand upon the Tomographic Absorption Reconstruction and Density Inference Scheme (TARDIS) in order to include multiple tracers while reconstructing matter density fields at Cosmic Noon (z ~ 2-3). In particular, we jointly…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-26 Benjamin Horowitz , Benjamin Zhang , Khee-Gan Lee , Robin Kooistra
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