Related papers: A Wavelet Space-Scale-Decomposition Analysis of St…
We have studied a sample of 1084 intervening absorption systems with 2.15$\le z_{ab}\le$5.2, having log(N$_{\rm HI}$) $>$ 20.0 in the spectra of QSOs in Sloan Digital Sky Survey (SDSS) data release 7 (DR7), with the aim of understanding the…
We present here new GHRS observations of Lyman-alpha absorption lines associated with groups or clusters toward the QSOs 1545+2101 and 0850+4400. In the first case we have identified at least eight distinct Lyman-alpha absorption features,…
Absorption-line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine-structure constant, alpha, and the proton-to-electron mass ratio, mu = m_p/m_e, as…
We report the large scale structure and clustering analysis of Ly$\alpha$ emitters (LAEs) and Ly$\alpha$ blobs (LABs) at $z=2.2-2.3$. Using 3,341 LAEs, 117 LABs, and 58 bright (Ly$\alpha$ luminosity $L_{\rm Ly\alpha}>10^{43.4}$ erg…
We have obtained spatially resolved spectra of the z=3.911 triply imaged QSO APM08279+5255 using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). We study the line of sight equivalent width (EW)…
We present the first clustering measurement of Strong Blended Lyman $\alpha$ (SBLA) absorption systems by measuring their cross-correlation with the Lyman $\alpha$ forest. SBLAs are a new population of absorbers detected within the Lyman…
The sensitivity and wide area reached by ongoing and future wide-field optical surveys allows for the detection of an increasing number of galaxy clusters uniquely through their weak lensing (WL) signal. This motivates the development of…
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…
We calculate theoretical population ratios of the ground fine-structure levels of some atoms/ions which typically exhibit UV lines in the spectra of QSO absorbers redward the Ly-alpha forest: C0, C+, O0, Si+ and Fe+. The most reliable…
A method for the recovery of the real space line-of-sight mass density field from Lyman absorption in QSO spectra is presented. The method makes use of a Lucy-type algorithm for the recovery of the HI density. The matter density is inferred…
The Effective Field Theory of Large-Scale Structure (EFTofLSS) is a formalism that allows us to predict the clustering of Cosmological Large-Scale Structure in the mildly non-linear regime in an accurate and reliable way. After validating…
We present the results of a survey for super Lyman limit systems (SLLS; defined to be absorbers with 19.0 <= log(NHI) <= 20.3 cm^-2) from a large sample of high resolution spectra acquired using the Keck and Magellan telescopes.…
We report the discovery of a "super-damped" Lyman-alpha absorber at $z_{abs}=2.2068$ toward QSO Q1135-0010 in the Sloan Digital Sky Survey, and follow-up VLT UVES spectroscopy. Voigt profile fit to the DLA line indicates log $N_{\rm H I} =…
The main properties of Damped Lyman alpha (DLA) systems are briefly reviewed with the aim of studying the nature and evolution of the galaxies associated with this class of QSO absorbers. Candidate DLA galaxies identified at z </= 1 in the…
Combining a new, increased dataset of 8 QSOs covering the Ly-alpha forest at redshifts 1.5 < z < 3.6 from VLT/UVES observations with previously published results, we have investigated the properties of the Ly-alpha forest at 1.5 < z < 4. We…
We present an overview of a multi-wavelength survey of the Shapley supercluster (SSC; z~0.05) covering a contiguous area of 260 h^-2_70 Mpc^2 including the supercluster core. The project main aim is to quantify the influence of…
Simulation-based inference (SBI) has become an important tool in cosmology for extracting additional information from observational data using simulations. However, all cosmological simulations are approximations of the actual universe, and…
We have analyzed the clustering of C IV absorption line systems in an extensive new catalog of heavy element QSO absorbers. The catalog permits exploration of clustering over a large range in both scale (from about 1 to over 300 Mpc) and…
We present six strongly gravitationally lensed Ly-$\alpha$ Emitters (LAEs) at $z\sim4-5$ with HST narrowband imaging isolating Ly-$\alpha$. Through complex radiative transfer Ly-$\alpha$ encodes information about the spatial distribution…
We have obtained spectroscopy of Q 1343+266 AB, a pair of quasars at redshift z = 2.03 with a projected separation of 9.5 arcseconds. This system is well-suited for probing the Ly-alpha forest, since the two component spectra show several…