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Galaxies are surrounded by large reservoirs of gas, mostly hydrogen, fed by inflows from the intergalactic medium and by outflows due to galactic winds. Absorption-line measurements along the sightlines to bright and rare background quasars…

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

Recent results have shown that a substantial fraction of high-redshift Lyman alpha galaxies contain considerable amounts of dust. This implies that Lyman alpha galaxies are not primordial, as has been thought in the past. However, this dust…

It has been suggested that radiative transfer effects may explain the unusually high equivalent widths (EWs) of the Lya line, observed occasionally from starburst galaxies, especially at high redshifts. If the dust is locked up inside…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Peter Laursen , Florent Duval , Göran Östlin

We present Monte Carlo calculations of Lyman alpha (Lya) radiative transfer through collapsing gas clouds, representing proto-galaxies that are caught in the process of their assembly. Such galaxies produce Lya flux over an extended solid…

Astrophysics · Physics 2008-11-26 Mark Dijkstra , Zoltan Haiman , Marco Spaans

We re-analyse high redshift and high resolution Lyman-$\alpha$ forest spectra considered in (Viel et al 2013), seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-18 Antonella Garzilli , Alexey Boyarsky , Oleg Ruchayskiy

A scenario is explored in which Lyman alpha absorbers at low redshift arise from lines of sight through extended galaxy disks, including those of dwarf and low surface brightness galaxies. A population of galaxies is simulated based upon…

Astrophysics · Physics 2009-10-30 Suzanne M. Linder

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

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-$\alpha$(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 predictions of Ly-alpha forest-galaxy correlations at z=3 from Eulerian simulations that include the effects of galactic winds, driven primarily by supernova explosions. Galactic winds produce expanding bubbles of shock-heated…

Astrophysics · Physics 2009-11-10 Juna A. Kollmeier , Jordi Miralda-Escude , Renyue Cen , Jeremiah P. Ostriker

We study the intergalactic transmission of radiation in the vicinity of the Ly{\alpha} wavelength. Simulating sightlines through the intergalactic medium (IGM) in detailed cosmological hydrosimulations, the impact of the IGM on the shape of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Peter Laursen , Jesper Sommer-Larsen , Alexei O. Razoumov

Combining a new, increased dataset of 8 QSOs covering the Ly-alpha forest at redshifts 1.5 < z < 3.6 from VLT/UVES observations with previously published results, we have investigated the properties of the Ly-alpha forest at 1.5 < z < 4. We…

Large surveys for Lyman-alpha emitting (LAE) galaxies have been proposed as a new method for measuring clustering of the galaxy population at high redshift with the goal of determining cosmological parameters. However, Lyman-alpha radiative…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Bradley Greig , Eiichiro Komatsu , J. Stuart B. Wyithe

While the Lyman-$\alpha$ (Ly$\alpha$) forest traces the large-scale matter distribution over a wide range of redshift, its three-dimensional (3D) clustering at $z < 2$ has not yet been measured. We investigate the prospects for measuring…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 Ting Tan , Huanyuan Shan , Eric Armengaud

The distribution of absorption lines in the spectra of distant quasars, called the Lyman-$\alpha$ (Ly-$\alpha$) forest, is a unique probe of cosmology and the intergalactic medium at high redshifts and small scales. The statistical power of…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Roger de Belsunce , Mikhail M. Ivanov , James M. Sullivan , Kazuyuki Akitsu , Shi-Fan Chen

We present results on the evolution and clustering of Ly-alpha lines at low z. The sample contains 1298 Ly-alpha lines from 165 quasar spectra mined from the archives of the HST/FOS. Our sample extends to z=1.7, slightly higher than the…

Astrophysics · Physics 2009-11-07 Adam Dobrzycki , Jill Bechtold , Jennifer Scott , Miwa Morita

The two-point correlation function, $\xi$, of Lyman-alpha forest is found to be large, $\xi = 1.8^{+1.6}_{-1.2}$, > 90% confidence level, on the scale of 250-500 km/s for a sample of absorbers (0 < z < 1.3) assembled from HST Key Project…

Astrophysics · Physics 2009-10-28 Andrew Ulmer

We combine predictions for several hierarchical cosmogonies with observational evidence on damped Lyman alpha systems to establish a correspondence between the high redshift galaxy population and the properties of damped Lyman alpha…

Astrophysics · Physics 2009-10-31 Martin G. Haehnelt , Matthias Steinmetz , Michael Rauch

Ram pressure stripping of the hot gas that surrounds normal galaxies as they fall into groups and clusters (also referred to as `strangulation' or `starvation') is generally thought to shut down star formation on a time scale of a few Gyr.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Yannick M. Bahe , Ian G. McCarthy , Robert A. Crain , Tom Theuns