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We identify a concordant model for the intergalactic medium (IGM) at redshift z=1.9 that uses popular values for cosmological and astrophysical parameters and accounts for all baryons with an uncertainty of 6%. We have measured the amount…

We have performed high-resolution hydrodynamic simulations of the Lyman-alpha forest in a variety of popular cold dark matter dominated cosmologies, including a low density and a vacuum-dominated model. The fluctuation amplitude of these…

Astrophysics · Physics 2009-10-31 Tom Theuns , Anthony Leonard , Joop Schaye , George Efstathiou

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

Lyman-alpha forest lines in QSO spectra have typical widths of 20-50 km/s. Low column density absorbers in cosmological simulations are large, diffuse structures, and the Hubble flow across the spatially extended absorber is usually the…

Astrophysics · Physics 2007-05-23 David H. Weinberg , Lars Hernquist , Neal Katz , Rupert Croft , Jordi Miralda-Escudé

The intergalactic medium (IGM) is the dominant reservoir of baryons at all cosmic epochs. We investigate the evolution of the IGM from z=2-0 in 48 Mpc/h, 110-million particle cosmological hydrodynamic simulations using three prescriptions…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Romeel Davé , Benjamin D. Oppenheimer , Neal Katz , Juna A. Kollmeier , David H. Weinberg

The remarkable efficiency of the UVES spectrograph at the VLT has made it possible to push high-resolution, high-S/N ground observations of the Ly-a forest down to z~1.5, gaining new insight into the physical conditions of the intergalactic…

Astrophysics · Physics 2009-11-07 S. Cristiani , S. Bianchi , S. D'Odorico , T. -S. Kim

We study the distribution of low-redshift Ly$\alpha$ clouds in a CDM model using numerical simulations including photoionization and cooling of the baryonic component. The ionizing background is found to be efficient enough to keep most of…

Astrophysics · Physics 2016-08-30 Patrick Petitjean , Jan P. Mücket , Ron Kates

We investigate the metal species associated with the Ly$\alpha$ forest in the eBOSS quasar spectra. Metal absorption lines are revealed in the stacked spectra from cross-correlating the selected Ly$\alpha$ absorbers in the forest and the…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-31 Li Yang , Zheng Zheng , Hélion du Mas des Bourboux , Kyle Dawson , Matthew M. Pieri , Graziano Rossi , Donald P. Schneider , Axel de la Macorra

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

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

In the low density intergalactic medium (IGM) that gives rise to the Lyman-alpha forest, gas temperature and density are tightly correlated. The velocity scale of thermal broadening and the Hubble flow across the gas Jeans scale are of…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-12 Molly S. Peeples , David H. Weinberg , Romeel Davé , Mark A. Fardal , Neal Katz

We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body…

Astrophysics · Physics 2008-02-03 David H. Weinberg , Neal Katz , Lars Hernquist

We study the kinematics of the gaseous cosmic web at high redshift with Lyman alpha forest absorption in multiple QSO sightlines. Using a simple analytic model and a cosmological hydrodynamic simulation we constrain the underlying…

We have conducted pointed redshift surveys for galaxies in the direction of bright AGN whose HST far-UV spectra contain nearby (cz <~ 30,000 kms), low column density (12.5 <= log N_{HI} (cm s^{-2}) <= 14.5) Ly-alpha forest absorption…

Astrophysics · Physics 2009-11-07 Kevin M. McLin , John T. Stocke , R. J. Weymann , Steven V. Penton , J. Micheal Shull

We investigate the properties of the Lyman alpha forest as predicted by numerical simulations for a range of currently viable cosmological models. This is done in order to understand the dependencies of the forest on cosmological…

Astrophysics · Physics 2009-10-31 M. E. Machacek , G. L. Bryan , A. Meiksin , P. Anninos , D. Thayer , M. L. Norman , Y. Zhang

We present a set of ultra-large particle-mesh simulations of the LyA forest targeted at understanding the imprint of baryon acoustic oscillations (BAO) in the inter-galactic medium. We use 9 dark matter only simulations which can, for the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Martin White , Adrian Pope , Jordan Carlson , Katrin Heitmann , Salman Habib , Patricia Fasel , David Daniel , Zarija Lukic

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

The high redshift galaxy MS1512-cB58 (z=2.724, m_V=20.64) has been observed with the very efficient high resolution echelle spectrograph VLT/UVES. Although this is a very challenging observational program for a Southern hemisphere telescope…

Astrophysics · Physics 2009-11-07 S. Savaglio , N. Panagia , P. Padovani

The spatial distribution of Ly-alpha forest absorption systems toward a group of 8, closely spaced QSOs has been analysed and evidence for large scale structure has been found at <z> = 2.8. Our technique is based on the first and second…

Astrophysics · Physics 2007-05-23 J. Liske , J. K. Webb