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Related papers: Evolution in the Lyman-alpha forest

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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

We report observations of a luminous unresolved object at redshift z = 4.62, with a featureless optical spectrum redward of the Lyman alpha forest region, discovered from Sloan Digital Sky Survey (SDSS) commissioning data. The redshift is…

Astrophysics · Physics 2015-06-24 SDSS Collaboration , Xiaohui Fan

Hydrodynamic cosmological simulations predict that the average opacity of the Ly-alpha forest should increase in the neighborhood of galaxies because galaxies form in dense environments. Recent observations (Adelberger et al. 2002) confirm…

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

Lyman-$\alpha$(Ly$\alpha$) forest in the spectra of distant quasars encodes the information of the underlying cosmic density field at smallest scales. The modelling of the upcoming large and high-fidelity forest data using cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-10 Bhaskar Arya

We present a new measurement of the Ly${\alpha}$ forest power spectrum at $1.8 < z < 3.4$ using 74 Keck/HIRES and VLT/UVES high-resolution, high-S/N quasar spectra. We developed a custom pipeline to measure the power spectrum and its…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-03 Michael Walther , Joseph F. Hennawi , Hector Hiss , Jose Oñorbe , Khee-Gan Lee , Alberto Rorai , John O'Meara

In this paper we study asymptotic properties of random forests within the framework of nonlinear time series modeling. While random forests have been successfully applied in various fields, the theoretical justification has not been…

Machine Learning · Statistics 2020-08-07 Richard A. Davis , Mikkel S. Nielsen

We present the first constraints on the electron optical depth to reionization, $\tau_{\mathrm{e}}$, from the Lyman-$\alpha$ forest alone for physically motivated reionization models that match the reionization's end-point, $z_{\rm{end}}$,…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-02 Olga Garcia-Gallego , Vid Iršič , Martin G. Haehnelt , James S. Bolton

We evaluate the performance of the Lyman-$\alpha$ forest weak gravitational lensing estimator of Metcalf et al. on forest data from hydrodynamic simulations and ray-traced simulated lensing potentials. We compare the results to those…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 Patrick Shaw , Rupert A. C. Croft , R. Benton Metcalf

We review the current state of the theory of large scale structure in a warm dark matter (WDM) cosmological model. In particular, we focus on the non-linear modelling of the matter power spectrum and on the mass function of dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-18 Katarina Markovič , Matteo Viel

Null models of binary phylogenetic trees are useful for testing hypotheses on real world phylogenies. In this paper we consider phylogenies as binary trees without edge lengths together with a sampling measure and encode them as algebraic…

Probability · Mathematics 2020-06-17 Josué Nussbaumer , Anita Winter

Visualizing the high-redshift Universe is difficult due to the dearth of available data; however, the Lyman-alpha forest provides a means to map the intergalactic medium at redshifts not accessible to large galaxy surveys. Large-scale…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Jessi Cisewski , Rupert A. C. Croft , Peter E. Freeman , Christopher R. Genovese , Nishikanta Khandai , Melih Ozbek , Larry Wasserman

Recently, there has been a certain amount of activity around the theme of cosmological and astrophysical applications of noncommutative geometry models of particle physics. We study space-time non-commutativity applied to the hydrogen atom…

High Energy Physics - Phenomenology · Physics 2019-01-15 M. Moumni , A. BenSlama , S. Zaim

We present moderate resolution data for 39 QSOs at z $\approx$ 2 obtained at the Multiple Mirror Telescope. These data are combined with spectra of comparable resolution of 60 QSOs with redshifts greater than 1.7 found in the literature to…

Astrophysics · Physics 2009-10-31 J. Scott , J. Bechtold , A. Dobrzycki

The inhomogeneous cosmological reionization process leaves tangible imprints in the intergalactic medium down to z=4-5. The Lyman-alpha forest flux power spectrum provides a potentially powerful probe of the epoch of reionization. With the…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Renyue Cen , Patrick McDonald , Hy Trac , Abraham Loeb

The three-dimensional distribution of the Ly$\alpha$ forest has been extensively used to constrain cosmology through measurements of the baryon acoustic oscillations (BAO) scale. However, more cosmological information could be extracted…

We address the problem of inferring the three-dimensional matter distribution from a sparse set of one-dimensional quasar absorption spectra of the Lyman-$\alpha$ forest. Using a Bayesian forward modelling approach, we focus on extending…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Natalia Porqueres , Oliver Hahn , Jens Jasche , Guilhem Lavaux

We directly measure the evolution of the intergalactic Lya 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 the ESI and HIRES…

Astrophysics · Physics 2009-11-13 C. -A. Faucher-Giguere , J. X. Prochaska , A. Lidz , L. Hernquist , M. Zaldarriaga

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

We present constraints on the amplitude and shape of the matter power spectrum and the density of dark matter within the framework of a standard LambdaCDM model. We use a Markov Chain Monte Carlo approach to combine independent measurements…

Astrophysics · Physics 2008-11-26 J. Lesgourgues , M. Viel , M. G. Haehnelt , R. Massey
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