Related papers: The Wouthuysen-Field effect in a clumpy intergalac…
We present an analysis of the Lyman alpha forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9 < z < 1.9) are studied. The amount of baryons in the diffuse…
The observed scatter in intergalactic Lyman-$\alpha$ opacity at $z \lesssim 6$ requires large-scale fluctuations in the neutral fraction of the intergalactic medium (IGM) after the expected end of reionization. Post-reionization models that…
The reionization of hydrogen in the intergalactic medium (IGM) is a crucial landmark in the history of the universe, but the processes through which it occurs remain mysterious. In particular, recent numerical and analytic work suggest that…
We present observations of a peculiar Lyman alpha-emitting galaxy at redshift 3.344, discovered in a deep, blind spectroscopic survey for faint Lyman alpha emitters with the Magellan II telescope in the Hubble Ultra Deep Field (HUDF). The…
When modelling the ionisation of gas in the intergalactic medium after reionisation, it is standard practice to assume a uniform radiation background. This assumption is not always appropriate; models with radiative transfer show that…
Aims: We aim to study the effects of an inhomogeneous interstellar medium (ISM) on the strength and the shape of the Lyman alpha (Lya) line in starburst galaxies. Methods: Using our 3D Monte Carlo Lya radiation transfer code, we study the…
Hydrogen Ly-alpha is our primary emission-line window into high redshift galaxies. Surprisingly, despite an extensive literature, Ly-alpha radiative transfer in the most realistic case of a dusty, multi-phase medium has not received…
Two methods are developed for solving the steady-state spherically symmetric radiative transfer equation for resonance line radiation emitted by a point source in the Intergalactic Medium. One method is based on solving the ray and moment…
We investigate the Lyman alpha line transfer in nearby and high redshift starbursting galaxies, where the effect of high optical depths and the role of dust in the scattering medium are expected to be conspicuous and should be treated in a…
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…
The sources which reionized the Intergalactic Medium by redshift ~6 are still unknown. A severe constraint on the ionization process is the low emissivity required to maintain the ionization in the Lyman-{\alpha} forest.…
We combine high resolution hydrodynamical simulations with an intermediate resolution, dark matter only simulation and an analytical model for the growth of ionized regions to estimate the large scale distribution and redshift evolution of…
Motivated by observational and theoretical work which both suggest very small scale ($\lesssim 1\,$pc) structure in the circum-galactic medium of galaxies and in other environments, we study Lyman-$\alpha$ (Ly$\alpha$) radiative transfer in…
We perform Lyman-alpha radiative transfer calculations for reproducing Lyman-alpha properties of star-forming galaxies at high redshifts. We model a galaxy as a halo in which the density distributions of Lyman-alpha sources and H I plus…
Models are presented for the Lyman alpha emission of dusty high-redshift galaxies by combining the Press-Schechter formalism with a treatment of the inhomogeneous dust distribution inside galaxies. It is found that the amount of Lyman alpha…
Recent observations of the Lyman-alpha forest show large-scale spatial variations in the intergalactic Lyman-alpha opacity that grow rapidly with redshift at z>5, far in excess of expectations from empirically motivated models. Previous…
The Lyman-alpha emission line dominates the far-ultraviolet spectra of late-type stars and is a major source for photodissociation of important molecules including H2O, CH4, and CO2 in exoplanet atmospheres. The incident flux in this line…
We show that spatial correlations in a stochastic large scale velocity field in an otherwise smooth intergalactic medium (homogeneous comoving density) superposed on the general Hubble flow, may cause a `line-like' structure in QSO spectra…
We examine the effect of Lyman continuum photons on the 21 cm background in the high-redshift universe. The brightness temperature of this transition is determined by the spin temperature T_s, which describes the relative populations of the…
The discovery of Lyman-alpha emission from galaxies at redshifts beyond z~6.5 should not be naively interpreted as implying that the intergalactic medium (IGM) had been reionized at higher redsifts. We show that a cluster of faint…