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Related papers: Background power subtraction in Lyman-alpha forest

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The correlation between Lyman-alpha absorption in the spectra of quasar pairs can be used to measure the transverse distance scale at z~2, which is sensitive to the cosmological constant (Omega_Lambda) or other forms of vacuum energy. Using…

Astrophysics · Physics 2009-11-07 Patrick McDonald

We present new measurements of the mean transmitted flux in the Ly-alpha forest over 2 < z < 5 made using 6065 quasar spectra from the Sloan Digital Sky Survey DR7. We exploit the general lack of evolution in the mean quasar continuum to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 George D. Becker , Paul C. Hewett , Gábor Worseck , J. Xavier Prochaska

Cosmological studies of the Lyman-Alpha (Lya) forest typically constrain parameters using two-point statistics. However, higher-order statistics, such as the three-point function (or its Fourier counterpart, the bispectrum) offer additional…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-28 Roger de Belsunce , James M. Sullivan , Patrick McDonald

Absorption lines in the Lyman-alpha forest can be thought of as peaks in neutral hydrogen density along lines of sight. The column density distribution (the number density of absorption lines as a function of column density) is then a…

Astrophysics · Physics 2007-05-23 Lam Hui , Nickolay Y. Gnedin , Yu Zhang

We present new measurements of the mean transmitted flux in the hydrogen Ly$\rm \alpha$ and a relative transmitted flux measurement in Ly$\rm \beta$ using 27,008 quasar spectra from the Fourteenth Data Release (DR14) of the Extended Baryon…

Astrophysics of Galaxies · Physics 2024-06-18 Jiani Ding , Piero Madau , J. Xavier Prochaska

The forest of Lyman-$\alpha$ absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic material. Its main observable -- the 1D flux…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-19 Bruno Villasenor , Brant Robertson , Piero Madau , Evan Schneider

We have considered the prospects for measuring the cross Warm Dark Matter (WDM) power spectrum of the redshifted HI 21-cm signal and the Lyman-$\alpha$ forest and thereby constraining WDM mass using observations with upcoming…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Anjan Kumar Sarkar , Ashis Kumar Pal , Tapomoy Guha Sarkar

We examine the statistics of the low-redshift Lyman-alpha forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations…

It is shown how wavelets may be used to analyse the absorption properties of the Lya forest. The Discrete Wavelet Transform of a QSO spectrum is used to decompose the light fluctuations that comprise the forest into orthogonal wavelets. It…

Astrophysics · Physics 2009-10-31 A. Meiksin

We use the Sherwood-Relics suite of hybrid hydrodynamical and radiative transfer simulations to model the effect of inhomogeneous reionisation on the 1D power spectrum of the \Lya forest transmitted flux at redshifts $4.2\leq z \leq 5$.…

We analyze the Ly alpha forest properties of a sample of 15 high redshift quasars lying between z = 4.42 and z = 5.75, using high signal-to-noise spectra obtained with ESI on the Keck II 10 m telescope. The distribution of transmissions in…

Astrophysics · Physics 2009-11-07 Antoinette Songaila , Lennox L. Cowie

Observations of the Lyman-$\alpha$ (Ly$\alpha$) forest from spectroscopic surveys such as BOSS/eBOSS, or the ongoing DESI, offer a unique window to study the growth of structure on megaparsec scales. Interpretation of these measurements is…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-09 Christian Pedersen , Andreu Font-Ribera , Nickolay Y. Gnedin

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

The \lya forest at high redshifts is a powerful probe of reionization. Modeling and observing this imprint comes with significant technical challenges: inhomogeneous reionization must be taken into account while simultaneously being able to…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-21 Paulo Montero-Camacho , Christopher M. Hirata , Paul Martini , Klaus Honscheid

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

We investigate the promise of the Ly-alpha forest for high precision cosmology in the era of the Sloan Digital Sky Survey using low order N-point statistics. We show that with the existing data one can determine the amplitude, slope and…

Astrophysics · Physics 2009-11-07 R. Mandelbaum , P. McDonald , U. Seljak , R. Cen

The hydrogen Ly$\alpha$ forest is an important probe of the $z>2$ Universe that is otherwise challenging to observe with galaxy redshift surveys, but this technique has traditionally been limited to 1D studies in front of bright quasars.…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Khee-Gan Lee

The observed Lyman-$\alpha$ flux power spectrum (FPS) is suppressed on scales below $\sim~ 30~{\rm km~s}^{-1}$. This cutoff could be due to the high temperature, $T_0$, and pressure, $p_0$, of the absorbing gas or, alternatively, it could…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Antonella Garzilli , Andrii Magalich , Tom Theuns , Carlos S. Frenk , Christoph Weniger , Oleg Ruchayskiy , Alexey Boyarsky

(abridged) The flux power spectrum of the Lyman-alpha forest in quasar (QSO) absorption spectra is sensitive to a wide range of cosmological and astrophysical parameters and instrumental effects. Modelling the flux power spectrum in this…

Astrophysics · Physics 2015-06-24 Matteo Viel , Martin G. Haehnelt

We directly measure the evolution of the intergalactic Lyman-alpha effective optical depth, tau_eff, over the redshift range 2<z<4.2 from a sample of 86 high-resolution, high-signal-to-noise quasar spectra obtained with Keck/ESI,…

Astrophysics · Physics 2010-11-11 C. -A. Faucher-Giguere , J. X. Prochaska , A. Lidz , L. Hernquist , M. Zaldarriaga