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We discuss the implementation of Bayesian inversion methods in order to recover the properties of the intergalactic medium from observations of the neutral hydrogen Lyman-$\alpha$ absorptions observed in the spectra of high redshift quasars…

Astrophysics · Physics 2009-11-06 C. Pichon , J. L. Vergely , E. Rollinde , S. Colombi , P. Petitjean

The Ly$\alpha$ forest provides one of the best means of mapping large-scale structure at high redshift, including our tightest constraint on the distance-redshift relation before cosmic noon. We describe how the large-scale correlations in…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-02 Shi-Fan Chen , Zvonimir Vlah , Martin White

We measure the imprint of primordial baryon acoustic oscillations (BAO) in the correlation function of Ly$\alpha$ absorption in quasar spectra from the Baryon Oscillation Spectroscopic Survey (BOSS) and the extended BOSS (eBOSS) in Data…

We present a model for spectrophotometric calibration errors in observations of quasars from the third generation of the Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) and describe the correction…

Instrumentation and Methods for Astrophysics · Physics 2016-11-15 Daniel Margala , David Kirkby , Kyle Dawson , Stephen Bailey , Michael Blanton , Donald P. Schneider

We present a method to make predictions with sets of correlated data values, in this case QSO flux spectra. We predict the continuum in the Lyman-Alpha forest of a QSO, from 1020 -- 1216 A, using the spectrum of that QSO from 1216 -- 1600 A…

Astrophysics · Physics 2009-11-10 Nao Suzuki , David Tytler , David Kirkman , John M. O'Meara , Dan Lubin

(Abridged) We investigate the importance of several numerical artifacts such as lack of resolution on spectral properties of the Lyman alpha forest as computed from cosmological hydrodynamic simulations in a standard cold dark matter…

Astrophysics · Physics 2009-10-30 Tom Theuns , Anthony Leonard , George Efstathiou , F. R. Pearce , P. A. Thomas

This article introduces a flexible and adaptive nonparametric method for estimating the association between multiple covariates and power spectra of multiple time series. The proposed approach uses a Bayesian sum of trees model to capture…

Methodology · Statistics 2021-10-01 Yakun Wang , Zeda Li , Scott A. Bruce

We forecast the prospects for cross-correlating future line intensity mapping (LIM) surveys with the current and future Ly-$\alpha$ forest data. We use large cosmological hydrodynamic simulations to model the expected emission signal for…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-03 Mahdi Qezlou , Simeon Bird , Adam Lidz , Guochao Sun , Andrew B. Newman , Gwen C. Rudie , Yueying Ni , Rupert Croft , Tiziana Di Matteo

We compare two state-of-the-art numerical codes to study the overall accuracy in modeling the intergalactic medium and reproducing Lyman-$\alpha$ forest observables for DESI and high-resolution data sets. The codes employ different…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-30 Solène Chabanier , J. D. Emberson , Zarija Lukić , Jesus Pulido , Salman Habib , Esteban Rangel , Jean Sexton , Nicholas Frontiere , Michael Buehlmann

We measure the effective optical depth in the Lyman-alpha (Ly$\alpha$) forest using 40,035 quasar spectra from the Twelfth Data Release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS) of SDSS-IV. A rigorous selection based on…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-08 Vikrant Kamble , Kyle Dawson , Hélion du Mas des Bourboux , Julian Bautista , Donald P. Schneider

We present a new technique for detecting structure on Mpc scales in the Lyman-alpha forest. The technique is easy to apply in practice since it does not involve absorption line fitting but is rather based on the statistics of the…

Astrophysics · Physics 2009-10-30 J. Liske , J. K. Webb , R. F. Carswell

We present the large-scale 3-point correlation function (3PCF) of the SDSS DR12 CMASS sample of $777,202$ Luminous Red Galaxies, the largest-ever sample used for a 3PCF or bispectrum measurement. We make the first high-significance…

The analysis of the Lyman-alpha forest of absorption lines in quasar spectra has emerged as a potentially powerful technique to constrain the linear matter power spectrum. In most previous work, the amplitude of the ionizing background was…

Astrophysics · Physics 2009-11-11 Adam Lidz , Katrin Heitmann , Lam Hui , Salman Habib , Michael Rauch , Wallace L. W. Sargent

Measurements of the Ly$\alpha$ forest based on large numbers of quasar spectra from sky surveys such as SDSS/eBOSS accurately probe the distribution of matter on small scales and thus provide important constraints on several ingredients of…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-22 Michael Walther , Eric Armengaud , Corentin Ravoux , Nathalie Palanque-Delabrouille , Christophe Yèche , Zarija Lukić

The baryon-acoustic oscillation (BAO) feature in the Lyman-$\alpha$ forest is one of the key probes of the cosmic expansion rate at redshifts z~2.5, well before dark energy is believed to have become dynamically significant. A key advantage…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 Christopher M. Hirata

The distribution of absorption lines in the spectra of distant quasars, called the Lyman-$\alpha$ (Ly-$\alpha$) forest, is a unique probe of cosmology and the intergalactic medium at high redshifts and small scales. The statistical power of…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Roger de Belsunce , Mikhail M. Ivanov , James M. Sullivan , Kazuyuki Akitsu , Shi-Fan Chen

We present the Lyman-$\alpha$ Continuum Analysis Network (LyCAN), a Convolutional Neural Network that predicts the unabsorbed quasar continuum within the rest-frame wavelength range of $1040-1600$ Angstroms based on the red side of the…

As a flexible nonparametric learning tool, the random forests algorithm has been widely applied to various real applications with appealing empirical performance, even in the presence of high-dimensional feature space. Unveiling the…

Statistics Theory · Mathematics 2022-09-27 Chien-Ming Chi , Patrick Vossler , Yingying Fan , Jinchi Lv

In this work, we explore the application of intensity mapping to detect extended Ly$\alpha$ emission from the IGM via cross-correlation of PAUS images with Ly$\alpha$ forest data from eBOSS and DESI. Seven narrow-band (FWHM=13nm) PAUS…

We study approximation algorithms for the forest cover and bounded forest cover problems. A probabilistic $2+\epsilon$ approximation algorithm for the forest cover problem is given using the method of dual fitting. A deterministic algorithm…

Data Structures and Algorithms · Computer Science 2024-11-26 Daya Ram Gaur , Barun Gorain , Shaswati Patra , Rishi Ranjan Singh