相关论文: A framework to measure the properties of intergala…
The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter $\gamma$. We describe a new method to measure $\gamma$…
We investigate a method to determine the temperature-density relation of the intergalactic medium (IGM) at z~2-4 using quasar absorption line systems. Using a simple model combined with numerical simulations we show that there is a lower…
We present a theoretical framework for linking quasar properties, such as quasar age, to the surrounding Ly$\alpha$ emission intensity. In particular, we focus on a method for mapping the large-scale structure of Ly$\alpha$ emission…
The evolution of the temperature in the intergalactic medium is related to the reionization of hydrogen and helium, and has important consequences for our understanding of the Lya forest and of galaxy formation in gravitational models of…
(Modified) We measure the distribution of carbon in the intergalactic medium as a function of redshift z and overdensity delta. Using a hydrodynamical simulation to link the H I absorption to the density and temperature of the absorbing…
The distribution and the abundance of metals in the intergalactic medium (IGM) have strong implications on galaxy formation and evolution models. The ionic transitions of heavy elements in quasar spectra can probe both the mechanisms and…
We search for the most suitable set of cosmological parameters that describes the observable universe. The search includes the possibility of quintessential flat universes, i.e., the analysis is restricted to the determination of the…
We propose a new method of analysis for the \lya forest, namely to measure the 1-point and 2-point joint probability distribution of the transmitted flux. The results for a sample of seven observed quasars and from two simulations of…
We present 40 fully hydrodynamical numerical simulations of the intergalactic gas that gives rise to the Ly-alpha forest. We make artificial spectra from each and measure three output parameters: the mean flux, a measure of the most common…
We present predictions for the one-point probability distribution and cumulants of the transmitted QSO flux in the high redshift Lyman-$\alpha$ Forest. We make use of the correlation between the Lyman-$\alpha$ optical depth and the…
Quasar spectra provide a unique opportunity to investigate the intergalactic medium at high redshifts. The spectral analysis of the Ly$\alpha$ forest allows us to constrain the effective equation of state of the intergalactic medium and its…
The intergalactic medium (IGM) around quasars is shaped by their dense environments and by their excess ionizing radiation, forming a "quasar proximity zone" whose size and anisotropy depend on the quasar's halo mass, luminosity, age, and…
An extremely careful analysis of the forest of weak metal-line systems at z ~ 2 has allowed the separation into individual `single-phase ionization' components with accurate parameters. The systems typically span several hundred km/s and…
A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the…
The production and distribution of metals in the diffuse intergalactic medium (IGM) have implications for galaxy formation models and the baryon (re)cycling process. The relative abundance of metals in high versus low-ionization states has…
We investigate the prospects for detecting and constraining density and temperature inhomogeneities in the circumgalactic medium (CGM) using absorption measurements of metal ions. Distributions in the gas thermal properties could arise from…
In this article, the temperature-density relation of the intergalactic medium was studied in the region $1.6 \leq z < 2.0$ divided into two bins. For this purpose, the Ly-$\alpha$ forest decomposition into individual absorption profiles was…
We have performed a detailed statistical study of the evolution of structure in a photoionized intergalactic medium (IGM) using analytical simulations to extend the calculation into the mildly non-linear density regime found to prevail at z…
We present measurements of carbon, oxygen, silicon, and iron in quasar absorption systems existing when the universe was roughly one billion years old. We measure column densities in nine low-ionization systems at 4.7 < z < 6.3 using Keck,…
We analyze the clustering properties of a high-resolution (~10 km/s) sample of about 1600 Lyman-alpha lines in the spectra of 15 quasars, obtained in the framework of an ESO key-programme with the addition of literature data. The two-point…