Related papers: Column density distribution of galactic Ly-alpha a…
We measure the effect of high column density absorbing systems of neutral hydrogen (HI) on the one-dimensional (1D) Lyman-alpha forest flux power spectrum using cosmological hydrodynamical simulations from the Illustris project. High column…
We present 3D resonant radiative transfer simulations of the spatial and spectral diffusion of the Lya radiation from a central source in the host galaxies of high column density absorption systems at z ~ 3. The radiative transfer…
The spatial distribution of Ly-alpha forest absorption systems towards ten QSOs has been analysed to search for large-scale structure over the redshift range 2.2 < z < 3.4. The QSOs form a closely spaced group on the sky and are…
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 study the formation of damped \lya and Lyman limit absorbers in a hierarchical clustering scenario using a gas dynamical simulation of an $\Omega = 1$, cold dark matter universe. In the simulation, these high column density systems are…
We investigate the properties of the HI Ly-a absorption systems (Ly-a forest) within and around galaxy voids at z<0.1. We find a significant excess (>99% c.l.) of Ly-a systems at the edges of galaxy voids with respect to a random…
We discuss the origin and physical nature of the Lya forest absorption systems as found in hydrodynamical simulations of the Intergalactic Medium in a standard Cold Dark Matter cosmology (Omega=1, H0=50 km/s/Mpc, sigma_8=0.7). The…
An extremely careful separation of the weak metal-line systems relating to the Lyman forest absorbers into individual ``single-phase ionization'' components with accurate parameters has yielded a large sample in the wide redshift range 1.9…
Recent abundance measurements in damped Lyman-alpha galaxies, supplemented with unpublished Keck observations, are discussed. The metallicity distribution with cosmic time is examined for clues about the degree of enrichment, the onset of…
Quasar absorbers provide a powerful observational tool with which to probe both galaxies and the intergalactic medium up to high redshift. We present a study of the evolution of the column density distribution, f(N,z), and total neutral…
We investigate the metal species associated with the Ly$\alpha$ forest in the eBOSS quasar spectra. Metal absorption lines are revealed in the stacked spectra from cross-correlating the selected Ly$\alpha$ absorbers in the forest and the…
We measure the cosmological bias factor of DLAs from their cross-correlation with the Ly$\alpha$ forest absorption, as a function of the DLA metal strength, defined from an average of equivalent widths of the strongest detectable…
Using a sample of 92 UV continuum-selected, spectroscopically identified galaxies with <z> = 2.65, all of which have been imaged in the Ly-a line with extremely deep narrow-band imaging, we examine galaxy Ly-a emission profiles to very…
The physical origin of diffuse Ly$\alpha$ halos (LAHs) around star-forming galaxies is still a matter of debate. We present the dependence of LAH luminosity ($L({\rm Ly}\alpha)_H$) on the stellar mass ($M_\star$), $SFR$, color excess…
We consider various possible scenarios to explain the recent observation of a claimed broad H$\alpha$ absorption in our Galactic halo with peak optical depth $\tau \simeq 0.01$ and equivalent width $W \simeq 0.17 \, \rm \AA$. We show that…
We calculate the neutral hydrogen column density of self-absorption in QSOs predicted in a model where the QSOs are located in the same halos that contain the gas in damped Lya absorption systems. The model is parameterized by the…
We present a detailed analysis of a high resolution spectrum of the damped Ly$\alpha$ system at $z_{\rm abs}$~=~2.8112toward PKS~0528-250. The absorption redshift is slightly larger than the emission redshift of the quasar. We estimate the…
In this work, I investigate the properties of Lyman limit systems (LLSs) using state-of-the-art zoom-in cosmological galaxy formation simulations with on the fly radiative transfer, which includes both the cosmic UV background (UVB) and…
We investigate Damped Ly-alpha absorbing galaxies (DLA galaxies) at low redshifts z<1 in the hierarchical structure formation scenario to clarify the nature of DLA galaxies because observational data of such galaxies mainly at low redshifts…
We propose that cooling outflows from star-forming dwarf galaxies that are spatially correlated with but unbound to bright galaxies may account for the low column QSO Ly$\alpha$ forests, providing an explanation for both the heavy elements…