Related papers: Non-Voigt Lyman-alpha absorption line profiles
The Voigt profile - a convolution of a Gaussian and a Lorentzian - accurately describes the absorption lines of atomic and molecular gases at low probe powers. Fitting such to experimental spectra yields both the Lorentzian natural…
We re-examine scattering of photons near the Lyman-alpha resonance in the intergalactic medium (IGM). We first derive a general integral solution for the radiation field around resonance when spin diffusivity is ignored. Our solution shows…
We present an analysis of the non-Gaussianity in the distribution of Ly$\alpha$ forest lines in the QSO absorption spectra. Statistical tests performed on this data indicate that there may be large scale structure even though the power…
In gravitational instability models, \lya absorption arises from a continuous fluctuating medium, so that spectra provide a non-linear one-dimensional ``map'' of the underlying density field. We characterise this continuous absorption using…
We present the target selection, observations, and data reduction and analysis process for a program aimed at discovering numerous, weak (equivalent width < 100 mA) Lya absorption lines in the local Universe (0.003 < z < 0.069). The purpose…
We present a new method for determining the thermal state of the intergalactic medium based on Voigt profile decomposition of the Ly$\alpha$ forest. The distribution of Doppler parameter and column density ($b$-$N_{\text{HI}}$ distribution)…
We study the physical properties of the Lyman-alpha forest by applying the inversion method described by Pichon et al. (2001) to the high resolution and high S/N ratio spectrum of the z_em=2.40 quasar HE 1122-1628 obtained during Science…
While it is possible to explain Lyman alpha absorber counts at low redshift using gas which is associated with moderately extended galaxies (Linder 1997), absorbers are often observed to be associated with galaxies at larger impact…
We analyzed the absorption line spectra of all quasars observed with the high resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for 334 quasars, and present line lists and…
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…
The forest of Lyman-alpha absorption lines seen in the spectra of distant quasars has become an important probe of the distribution of matter in the Universe. We use large, hydrodynamical simulations from the OWLS project to investigate the…
Simulations of the formation of large-scale structure predict that dark matter, low density highly ionized gas, and galaxies form 10 40 Mpc scale filaments. These structure are easily recognized in the distribution of galaxies, but have not…
In this work, we analyze the Lyman-$\alpha$ forest in cosmological hydrodynamical simulations of chameleon-type f(R) gravity with the goal to assess whether the impact of such models is detectable in absorption line statistics. We carry out…
Galaxy formation depends critically on the physical state of gas in the circumgalactic medium (CGM) and its interface with the intergalactic medium (IGM), determined by the complex interplay between inflows from the IGM and outflows from…
Correlations measured in three dimensions in the Lyman-alpha forest are contaminated by the presence of the damping wings of high column density (HCD) absorbing systems of neutral hydrogen (HI; having column densities $N(\mathrm{HI}) >…
We measure the amount of absorption in the Lyman-alpha forest at 0 < z < 1.6 in HST FOS spectra of 74 QSOs. At 0 < z < 1.6 we find that 79% of the absorption is from the low density intergalactic medium, 12% from metals and 9% from the…
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…
We demonstrate that the lyman alpha forest flux power spectrum of ``randomised'' QSO absorption spectra is comparable in shape and amplitude to the flux power spectrum of the original observed spectra. In the randomised spectra a random…
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 present some statistical features of the large number of \lya absorption lines detected in high redshift quasar spectra, obtained by using the multifractal approach. In the analysed sample of 12 QSO sight--lines, 11 show scaling…