Related papers: A wavelet analysis of QSO spectra
As the Universe evolves, it develops a web of filamentary structure of matter. This cosmic web is filled with gas, with the most diffuse gas lying in the intergalactic regions. At low redshift, the gas is predominantly warm-hot, and one of…
We present a detailed review of large-scale structure (LSS) study using the discrete wavelet transform (DWT). After describing how one constructs a wavelet decomposition we show how this bases can be used as a complete statistical…
Using a cosmological simulation at redshift 5, we find that the baryon-rich cores of intergalactic filaments extending outward from galaxies commonly form isothermal gas cylinders in regions favorable to their formation. The central gas…
The importance of HST for the study of quasar absorption lines and of the nature of the intergalactic medium is illustrated by reviewing selected results from past HST observations. Topics reviewed include the study of Ly-alpha absorbers at…
A large fraction of the baryonic matter in the Universe is located in filaments in the intergalactic medium. However, the low surface brightness of these filaments has not yet allowed their direct detection except in very special regions in…
We briefly discuss the relevance of Lyman alpha forest observations for measuring cosmological parameters, comparing the properties of high z QSO spectra with those of artifical spectra from hydrodynamic simulations, based on hierarchical…
We discuss the feasibility of the detection of the 21cm forest in the diffuse IGM with the radio telescope LOFAR. The optical depth to the 21cm line has been derived using simulations of reionization which include detailed radiative…
During reionization, a fraction of galactic Ly$\alpha$ emission is scattered in the intergalactic medium (IGM) and appears as a diffuse light extending megaparsecs from the source. We investigate how to probe the properties of the early…
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…
At present, 30-40 per cent of the baryons in the local Universe is still undetected. According to theoretical predictions, this gas should reside in filaments filling the large-scale structure (LSS) in the form of a Warm-Hot Intergalactic…
The amplitude of the ionizing background that pervades the intergalactic medium (IGM) at the end of the epoch of reionization provides a valuable constraint on the emissivity of the sources which reionized the Universe. While measurements…
A model of Lyman limit QSO absorption systems is investigated where they are produced in gaseous galactic halos with a two-phase structure: a hot phase at the halo virial temperature in approximate pressure equilibrium, and a cold,…
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…
We present a comprehensive analysis of high resolution hydrodynamic simulations in terms of Lyman-alpha and Lyman-beta one dimensional flux power spectra ($P_{\alpha\alpha}$ and $P_{\beta\beta}$). In particular, we focus on the behaviour…
The wavelength range 912-2000A (hereafter far-UV) provides access to absorption lines of the interstellar medium (ISM), circumgalactic medium (CGM), and intergalactic medium (IGM) in phases spanning a wide range of ionization, density,…
Although the baryons in the intergalactic medium (IGM) trace dark matter on Mpc scales, small-scale (~100 kpc) fluctuations are suppressed by pressure support, analogous to the classical Jeans argument. This Jeans filtering scale has…
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…
Lyman alpha absorber correlations contain information about the underlying density distribution associated with a particular class of absorbers. As such, they provide an opportunity to independently measure the "bias" of the Lyman alpha…
The warm-hot intergalactic medium (warm-hot IGM, or WHIM) pervades the filaments of the Cosmic Web and harbours half of the Universe's baryons. The WHIM's thermodynamic properties are notoriously hard to measure. Here we estimate a galaxy…
We explore the multiphase structure of the circumgalactic medium (CGM) probed by synthetic spectra through a cosmological zoom-in galaxy formation simulation. We employ a Bayesian method for modelling a combination of absorption lines to…