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Models for structure formation attempt to predict the power spectrum of density perturbations in the present universe from the initial power spectrum and the nature of dark matter. Observational constraints on the power spectrum at…

Astrophysics · Physics 2007-05-23 K. Subramanian , T. Padmanabhan

It is shown that many properties of Ly-alpha forest absorbers can be derived using simple physical arguments. Analytical expressions are derived for the density and the size of an absorber as a function of its neutral hydrogen column…

Astrophysics · Physics 2007-05-23 Joop Schaye

We investigate the three-point correlation between the Lyman-$\alpha$ forest and the CMB weak lensing ($\delta_F \delta_F \kappa$) expressed as the cross-correlation between the CMB weak lensing field and local variations in the forest…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-24 Chi-Ting Chiang , Anže Slosar

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 observations of the Lyman alpha forest towards B2 1225+317 taken at a resolution of 18 km/s. A clean sample of Lyman alpha forest lines is extracted after a careful profile fitting analysis and removal of absorption lines of…

Astrophysics · Physics 2015-06-24 Pushpa Khare , R. Srianand , D. G. York , R. Green , D. Welty , Ke-Liang Huang , J. Bechtold

A simple consistency argument for hypothesis of the galactic halo origin of the Ly-alpha forest absorption lines is advanced, based on the recent determination of column-density vs. impact parameter relation for the low-redshift gaseous…

Astrophysics · Physics 2015-06-24 Milan M. Cirkovic , Srdjan Samurovic

We analyze the SDSS Ly-alpha forest P_F(k,z) measurement to determine the linear theory power spectrum. Our analysis is based on fully hydrodynamic simulations, extended using hydro-PM simulations. We account for the effect of absorbers…

We estimate the 1--D power spectrum and the integral density of neighbors in 14 QSO lines of sight. We discuss their variation with respect to redshift and column density and compare the results with standard CDM models.

Astrophysics · Physics 2007-05-23 L. Amendola , S. Savaglio

We present new simulations of the flux power spectrum of the Lyman $\alpha$ forest as a means to investigate the effects of time-dependent dark energy on structure formation. We use a linearized parameterization of the time-dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-18 Jared W. Coughlin , Grant J. Mathews , Lara Arielle Phillips , Ali P. Snedden , In-Saeng Suh

When measuring the one-dimensional power spectrum of the Ly$\alpha$ forest, it is common to measure the power spectrum in flux fluctuations red-ward of the Ly$\alpha$ emission of quasars and subtract this power from the measurements of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-13 Vid Iršič , Anže Slosar

We outline the physical picture of the high-redshift Ly-alpha forest that has emerged from cosmological simulations, describe statistical characteristics of the forest that can be used to test theories of structure formation, present a…

Recent cosmological tensions have rekindled the search for models beyond $\Lambda$CDM that cause a suppression of the matter power spectrum. Due to the small scales accessible to Lyman-$\alpha$ data they are an excellent additional tool to…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-26 Deanna C. Hooper , Nils Schöneberg , Riccardo Murgia , Maria Archidiacono , Julien Lesgourgues , Matteo Viel

High resolution N-body simulations of cold dark matter (CDM) models predict that galaxies and clusters have cuspy halos with excessive substructure. Observations reveal smooth halos with central density cores. One possible resolution of…

Astrophysics · Physics 2015-09-23 Vijay K. Narayanan , David N. Spergel , Romeel Davé , Chung-Pei Ma

Straightforward physical arguments are used to derive the properties of Lyman-alpha forest absorbers. It is shown that many aspects of the current physical picture of the forest, in particular the fact that the absorption arises in extended…

Astrophysics · Physics 2009-11-06 Joop Schaye

We present a novel technique for calculating \Lya forest correlations based on cell counts. It is applied to the line lists from 7 QSOs observed at high resolution ($\Delta v<25\kms$). Two spectra (Q0055$-$259 and Q0014$+$813) appear to be…

Astrophysics · Physics 2007-05-23 François R. Bouchet , Avery Meiksin

We investigate constraints on scalar dark matter (DM) by analyzing the Lyman-alpha forest, which probes structure formation at medium and small scales, and also by studying its cosmological consequences at high and low redshift. For scalar…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-18 Takeshi Kobayashi , Riccardo Murgia , Andrea De Simone , Vid Iršič , Matteo Viel

We investigate possible systematic errors in the recent measurement of the matter power spectrum from the Lyman-alpha forest by Croft et al. (2001). We find that for a large set of prior cosmological models the Croft et al. result holds…

Astrophysics · Physics 2009-11-07 Nickolay Y. Gnedin , Andrew J. S. Hamilton

We report a scaling of the mean matter density with the width of the saturated Lyman alpha absorptions. This property is established using the ``pseudo-hydro'' technique (Croft et al. 1998). It provides a constraint for the inversion of the…

Astrophysics · Physics 2009-11-07 Hu Zhan

The Lyman-$\alpha$ absorption spectrum associated with photons traversing the intergalactic medium allows us to probe the linear matter power spectrum down to relatively small distance scales. Finding ways of accurately evaluating…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-04 Keith R. Dienes , Fei Huang , Jeff Kost , Brooks Thomas , Hai-Bo Yu

In quintessence models, the dark energy content of the universe is described by a slowly rolling scalar field whose pressure and energy density obey an equation of state of the form p=w $\rho$; w is in general a function of time such that…

Astrophysics · Physics 2009-11-07 M. Viel , S. Matarrese , Tom Theuns , D. Munshi , Yun Wang