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Numerical hydrodynamical simulations are used to predict the expected absorption properties of the Lyman-Alpha forest for a variety of Cold Dark Matter dominated cosmological scenarios: CHDM, OCDM, LCDM, SCDM, and tCDM. Synthetic spectra…

Astrophysics · Physics 2009-11-06 A. Meiksin , G. Bryan , M. Machacek

We examine the statistics of the low-redshift Ly-alpha forest in an adaptive mesh refinement hydrodynamic cosmological simulation of sufficient volume to include distinct large-scale environments. We compare our HI column density…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 Stephanie Tonnesen , Britton D. Smith , Juna Kollmeier , Renyue Cen

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…

We compare the low redshift (z ~ 0.1) Lyman-alpha forest from hydrodynamical simulations with data from the Cosmic Origin Spectrograph (COS). We find tension between the observed number of lines with b-parameters in the range 25-45 km/s and…

Astrophysics of Galaxies · Physics 2017-04-19 M. Viel , M. G. Haehnelt , J. S. Bolton , T. -S. Kim , E. Puchwein , F. Nasir , B. P. Wakker

I apply the well controlled Hydro-PM approximation of Gnedin & Hui to model the column density distribution of the Lyman-alpha forest for 25 different flat cosmological scenarios, including variants of the standard CDM, tilted CDM, CDM with…

Astrophysics · Physics 2009-10-30 Nickolay Y. Gnedin

We investigate the effects of AGN heating and the ultraviolet background on the low-redshift Lyman-$\alpha$ forest column density distribution (CDD) using the Illustris simulation. We show that Illustris reproduces observations at $z =0.1$…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-08 Alex Gurvich , Blakesley Burkhart , Simeon Bird

We analyze the flux power spectrum and its covariance using simulated Lyman alpha forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques…

Astrophysics · Physics 2009-11-11 Hu Zhan , Romeel Dave , Daniel Eisenstein , Neal Katz

Understanding the sources responsible for reionizing the Universe is a key goal of observational cosmology. A discrepancy has existed between the metagalactic hydrogen ionization rate, Gamma_HI, predicted by early hydrodynamical simulations…

Astrophysics · Physics 2009-11-11 James S. Bolton , Martin G. Haehnelt , Matteo Viel , Volker Springel

We investigate the thermal history of the intergalactic medium (IGM) in the redshift interval z=1.7--3.2 by studying the small-scale fluctuations in the Lyman alpha forest transmitted flux. We apply a wavelet filtering technique to eighteen…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 A. Garzilli , J. S. Bolton , T. -S. Kim , S. Leach , M. Viel

We present results from the first high-resolution hydrodynamical simulations of non-Gaussian cosmological models. We focus on the statistical properties of the transmitted Lyman-alpha flux in the high redshift intergalactic medium. Imprints…

Astrophysics · Physics 2010-03-26 M. Viel , E. Branchini , K. Dolag , M. Grossi , S. Matarrese , L. Moscardini

We study the effect of different feedback prescriptions on the properties of the low redshift ($z\leq1.6$) Ly$\alpha$ forest using a selection of hydrodynamical simulations drawn from the Sherwood simulation suite. The simulations…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Fahad Nasir , James S. Bolton , Matteo Viel , Tae-Sun Kim , Martin G. Haehnelt , Ewald Puchwein , Debora Sijacki

We compare cosmological hydrodynamical simulations combined with the homogeneous metagalactic UV background (UVB) of Haardt & Madau (2012) (HM2012) to observations of the Lyman-alpha forest that are sensitive to the thermal and ionization…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Ewald Puchwein , James S. Bolton , Martin G. Haehnelt , Piero Madau , George D. Becker , Francesco Haardt

The absorption by neutral hydrogen in the intergalactic medium (IGM) produces the Ly$\alpha$ forest in the spectra of quasars. The Ly$\alpha$ forest absorbers have a broad distribution of neutral hydrogen column density $N_{\rm HI}$ and…

Astrophysics of Galaxies · Physics 2023-04-05 Li Yang , Zheng Zheng , T. -S. Kim

The density and temperature properties of the intergalactic medium (IGM) reflect the heating and ionization history during cosmological structure formation, and are primarily probed by the Lyman-alpha forest of neutral hydrogen absorption…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-26 Bruno Villasenor , Brant Robertson , Piero Madau , Evan Schneider

Hydrodynamic simulations of Lyman alpha clouds based on ab inito cosmological models have produced results that are in broad agreement with observations. However, further analyses have revealed that, with progressively higher numerical…

Astrophysics · Physics 2009-10-31 Renyue Cen , Greg L. Bryan

Spectra from the Keck HIRES instrument of the Lyman alpha forests in the lines of sight to the A and C components of the gravitationally lensed QSO Q1422+231 were used to investigate the structure of the intergalactic medium at mean…

Astrophysics · Physics 2009-11-06 Michael Rauch , Wallace L. W. Sargent , Thomas A. Barlow , Robert F. Carswell

We compare the improved measurement of the Lya forest flux probability distribution at 1.7<z<3.2 presented by Kim et al. (2007) to a large set of hydrodynamical simulations of the Lya forest with different cosmological parameters and…

Astrophysics · Physics 2009-11-13 J. S. Bolton , M. Viel , T. -S. Kim , M. G. Haehnelt , R. F. Carswell

Estimates of the metagalactic hydrogen ionization rate from the Lyman-alpha forest opacity in QSO absorption spectra depend on the complex density distribution of neutral hydrogen along the line-of-sight. We use a large suite of high…

Astrophysics · Physics 2009-11-10 James S. Bolton , Martin G. Haehnelt , Matteo Viel , Volker Springel

We present new measurements of the thermal state of the intergalactic medium (IGM) at $z\sim2.4$ derived from absorption line profiles in the Ly$\alpha$ forest. We use a large set of high-resolution hydrodynamical simulations to calibrate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 James S. Bolton , George D. Becker , Martin G. Haehnelt , Matteo Viel

Numerical simulations indicate that the smooth, photoionized intergalactic medium (IGM) responsible for the low column density Lyman-alpha forest follows a well defined temperature-density relation. We show that such an equation of state…

Astrophysics · Physics 2007-05-23 Joop Schaye , Tom Theuns , Anthony Leonard , George Efstathiou
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