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Related papers: Large-scale structure in the Lyman-alpha forest --…

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Continuum fitting is an important aspect of Lyman-alpha forest science, since errors in the estimated optical depths scale with the fractional continuum error. However, traditional methods of estimating continua in noisy and…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-27 Khee-Gan Lee , Nao Suzuki , David N. Spergel

We present a new method of finding protoclusters using tomographic maps of Ly$\alpha$ Forest flux. We review our method of creating tomographic flux maps and discuss our new high performance implementation, which makes large reconstructions…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-10 Casey W. Stark , Martin White , Khee-Gan Lee , Joseph F. Hennawi

This paper proposes a multi-spectral random forest classifier with suitable feature selection and masking for tree cover estimation in urban areas. The key feature of the proposed classifier is filtering out the built-up region using…

Computer Vision and Pattern Recognition · Computer Science 2023-06-12 Usman Nazir , Momin Uppal , Muhammad Tahir , Zubair Khalid

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 measure the effect of high column density absorbing systems of neutral hydrogen (HI) on the one-dimensional (1D) Lyman-alpha forest flux power spectrum using cosmological hydrodynamical simulations from the Illustris project. High column…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-10 Keir K. Rogers , Simeon Bird , Hiranya V. Peiris , Andrew Pontzen , Andreu Font-Ribera , Boris Leistedt

We use the LUQAS sample of 27 high resolution, high signal-to-noise QSO absorption spectra (Kim et al. 2004) and the results from Croft et al. (2002) together with a suite of high-resolution hydro-dynamical simulations run with the…

In this paper we critically examine predictions of the Lya forest within the standard cold dark matter (SCDM) model, paying particular attention to the low end of the column-density distribution. We show in particular that the width of…

Astrophysics · Physics 2009-10-30 Greg L. Bryan , Marie Machacek , Peter Anninos , Michael L. Norman

Using a suite of hydrodynamical simulations with cold dark matter, baryons, and neutrinos, we present a detailed study of the effect of massive neutrinos on the 1-D and 3-D flux power spectra of the Lyman-$\alpha$ (Ly$\alpha$) forest. The…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Christian Pedersen , Andreu Font-Ribera , Thomas D. Kitching , Patrick McDonald , Simeon Bird , Anže Slosar , Keir K. Rogers , Andrew Pontzen

Maps of the large-scale structure of the Universe at redshifts 2-4 can be made with the Lyman-alpha forest which are complementary to low redshift galaxy surveys. We apply the Wiener interpolation method of Caucci et al. to construct…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-08 Melih Ozbek , Rupert A. C. Croft , Nishikanta Khandai

Correlations in the Lyman-$\alpha$ (Ly$\alpha$) forest, both as a function of line of sight separation (1D) and 3D separation, provide a unique window to the distribution of matter at redshifts not accessible by current galaxy surveys.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-07 Martine Lokken , Andreu Font-Ribera , Patrick McDonald

We quantify the impact of massive neutrinos on the statistics of low density regions in the intergalactic medium (IGM) as probed by the Lyman-alpha forest at redshifts z=2.2--4. Based on mock but realistic quasar (QSO) spectra extracted…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-09 Francisco Villaescusa-Navarro , Mark Vogelsberger , Matteo Viel , Abraham Loeb

Simulations of the formation of large-scale structure predict that dark matter, low density highly ionized gas, and galaxies form 10 40 Mpc scale filaments. These structure are easily recognized in the distribution of galaxies, but have not…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-15 Bart P. Wakker , Audra K. Hernandez , David French , Tae-Sun Kim , Benjamin D. Oppenheimer , Blair D. Savage

An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar absorption line spectra with laboratory spectra provides a sensitive probe for…

In this letter, a novel method for change detection is proposed using neighborhood structure correlation. Because structure features are insensitive to the intensity differences between bi-temporal images, we perform the correlation…

Computer Vision and Pattern Recognition · Computer Science 2023-02-13 Mengmeng Wang , Zhiqiang Han , Peizhen Yang , Bai Zhu , Ming Hao , Jianwei Fan , Yuanxin Ye

Resonance lines encode rich information about astrophysical sources and their environments, yet fully analytic treatments of multi-line radiative transfer remain almost entirely unexplored. We present exact, closed-form solutions for…

Astrophysics of Galaxies · Physics 2026-02-18 Ethan Stace , Aaron Smith , Kevin Lorinc , Olof Nebrin

This paper presents an autonomous approach to tree detection and segmentation in high resolution airborne LiDAR that utilises state-of-the-art region-based CNN and 3D-CNN deep learning algorithms. If the number of training examples for a…

Robotics · Computer Science 2018-10-31 Lloyd Windrim , Mitch Bryson

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

We present a detailed review of large-scale structure (LSS) study using the discrete wavelet transform (DWT). After describing how one constructs a wavelet decomposition we show how this bases can be used as a complete statistical…

Astrophysics · Physics 2016-08-30 Li-Zhi Fang , Jesus Pando

We have conducted pointed redshift surveys for galaxies in the direction of bright AGN whose HST far-UV spectra contain nearby (cz <~ 30,000 kms), low column density (12.5 <= log N_{HI} (cm s^{-2}) <= 14.5) Ly-alpha forest absorption…

Astrophysics · Physics 2009-11-07 Kevin M. McLin , John T. Stocke , R. J. Weymann , Steven V. Penton , J. Micheal Shull

We derive an analytical expression for a novel large-scale structure observable: the line correlation function. The line correlation function, which is constructed from the three-point correlation function of the phase of the density field,…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Richard Wolstenhulme , Camille Bonvin , Danail Obreschkow