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Trend filtering---first introduced into the astronomical literature in Paper I of this series---is a state-of-the-art statistical tool for denoising one-dimensional signals that possess varying degrees of smoothness. In this work, we…

Instrumentation and Methods for Astrophysics · Physics 2022-02-01 Collin A. Politsch , Jessi Cisewski-Kehe , Rupert A. C. Croft , Larry Wasserman

We analyzed the absorption line spectra of all quasars observed with the high resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for 334 quasars, and present line lists and…

We investigate the large-scale inhomogeneities of the hydrogen ionizing radiation field in the Universe at redshift z=3. Using a raytracing algorithm, we simulate a model in which quasars are the dominant sources of radiation. We make use…

Astrophysics · Physics 2009-11-10 Rupert A. C. Croft

We present results from a survey of the Lyman alpha forest at 2.15<z<3.26 toward ten QSOs concentrated within a 1 degree field. We find correlations of the Lyman alpha absorption line wavelengths between different lines-of-sight over the…

Astrophysics · Physics 2007-05-23 G. M. Williger , A. Smette , C. Hazard , J. A. Baldwin , R. G. McMahon

We present a new method for probing the physical conditions and metal enrichment of the Intergalactic Medium: the composite spectrum of Ly-alpha forest absorbers. We apply this technique to a sample of 9480 Ly-alpha absorbers with redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Matthew M. Pieri , Stephan Frank , David H. Weinberg , Smita Mathur , Donald G. York

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

Probing the size and shape of the absorbers that lie in front of the QSOs, in particular the Ly alpha forest, we analyze 785 absorption lines in spectra of five QSOs in close groupings: a pair and a triplet. Both QSO groups have been…

Astrophysics · Physics 2009-10-30 Arlin Crotts , Yihu Fang

We make forecasts for the constraining power of the 1D Wavelet Scattering Transform (WST) when used with a Lyman-$\alpha$ forest cosmology survey. Using mock simulations and a Fisher matrix, we show that there is considerable cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-05 Hurum Maksora Tohfa , Simeon Bird , Ming-Feng Ho , Mahdi Qezlou , Martin Fernandez

The flux power spectra of the Lyman-alpha forest from a sample of 27 QSOs taken with the high resolution echelle spectrograph UVES on VLT are presented. We find a similar fluctuation amplitude at the peak of the ``3D'' flux power spectrum…

Astrophysics · Physics 2008-11-26 T. -S. Kim , M. Viel , M. G. Haehnelt , R. F. Carswell , S. Cristiani

We present high S/N echelle spectra of the recently discovered ultraluminous QSO APM 08279+5255 and use these data to re-examine the abundance of Carbon in Ly alpha forest clouds. In agreement with previous work, we find that approximately…

We explore the effect of applying a non-linear transformation to the Lyman-$\alpha$ forest transmitted flux $F=e^{-\tau}$ and the ability of analytic models to predict the resulting clustering amplitude. Both the large-scale bias of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-10 Xinkang Wang , Andreu Font-Ribera , Uros Seljak

We measure the power spectrum, P_F(k,z), of the transmitted flux in the Ly-alpha forest using 3035 high redshift quasar spectra from the Sloan Digital Sky Survey. This sample is almost two orders of magnitude larger than any previously…

The z > 2 Lyman-alpha (Lya) forest traces the underlying dark-matter distribution on large scales and, given sufficient sightlines, can be used to create 3D maps of large-scale structure. We examine the observational requirements to…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-23 Khee-Gan Lee , Joseph F. Hennawi , Martin White , Rupert Croft , Melih Ozbek

The flux/transmission power spectrum has become a popular statistical tool in studies of the high redshift ($z > 2$) Lyman-alpha forest. At low redshifts, where the forest has thinned out into a series of well-isolated absorption lines, the…

Astrophysics · Physics 2016-01-27 Lam Hui

The apparent angular positions of quasars are deflected on the sky by the gravitational field sourced by foreground matter. This weak lensing effect is measurable through the distortions it introduces in the lensed quasar spectra.…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-03 Patrick Shaw , Rupert A. C. Croft , R. Benton Metcalf

A wavelet transform spectrum analyzer operating in real time within the frequency range 3X10^(-5) - 1.3X10^5 Hz has been implemented on a low-cost Digital Signal Processing board operating at 150MHz. The wavelet decomposition of the signal…

Statistical Mechanics · Physics 2009-11-07 Doriano Brogioli , Alberto Vailati

The distribution of the absorption line broadening observed in the Ly$\alpha$ forest carries information about the temperature and widths of the filaments in the intergalactic medium (IGM). In this work, we present and test a new method for…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-04 Antonella Garzilli , Tom Theuns , Joop Schaye

We propose a new method of analysis for the \lya forest, namely to measure the 1-point and 2-point joint probability distribution of the transmitted flux. The results for a sample of seven observed quasars and from two simulations of…

The power spectrum of transmitted flux in the Ly$\alpha$ forest in spectra of distant quasars gives us an information about matter power spectrum on the smallest spatial scales which is very important for testing of different models of dark…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-15 G. Polinovskyi , M. Malygin

We use an automated Voigt-profile fitting procedure to extract statistical properties of the Ly$\alpha$ forest in a numerical simulation of an $\Omega=1$, cold dark matter (CDM) universe. Our analysis method is similar to that used in most…

Astrophysics · Physics 2007-05-23 Romeel Davé , Lars Hernquist , David H. Weinberg , Neal Katz