Related papers: Molecular absorption lines at high redshift

We present our investigation into the physical conditions of the gas in five intervening quasar absorption line systems along the line of sight toward the quasar PG 0117+213, with redshifts of z=0.57, z=0.72, z=1.04, z=1.32 and z=1.34.…

We present evidence that clumps of \lya lines are physically associated with about half of the extensive metal-line systems (absorption systems with four or more observed metal-line species) found in this paper, demonstrate that all four…

Gas-rich galaxies are selected efficiently via quasar absorption lines. Recently, a new perspective on such absorption-selected systems has opened up by studying the molecular gas content of absorber host galaxies using ALMA CO emission…

Galaxies often contain large reservoirs of molecular gas which shape their evolution. This can be through cooling of the gas -- which leads to star formation, or accretion onto the central supermassive black hole -- which fuels AGN activity…

Neutral hydrogen traces gravitational potentials. In the nearby universe, 21cm emission-line surveys show that the bulk of the HI resides in well-formed, optically-luminous galaxies. At high redshift, 21cm line absorption against background…

A search for radio recombination lines near 20 cm at z=0.193 and z=0.886 towards the gravitational lens system PKS 1830-211 has yielded upper limits on the line optical depth of 5 x 10^{-5} and 5 x10^{-4} at the two redshifts respectively.…

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…

We present high-resolution UV spectra of absorption-line systems toward the low-z QSO HS0624+6907 (z=0.3700). Coupled with spectroscopic galaxy redshifts, we find that many of these absorbers are integalactic gas clouds distributed within…

We present a physically-based absorption-line model for the spectroscopic study of the intergalactic medium (IGM). This model adopts results from Cloudy simulations and theoretical calculations by Gnat and Sternberg (2007) to examine the…

We combine emission line and X-ray luminosities for 45 sources from the Chandra Deep Field South (CDF-S), and seven HELLAS sources, to obtain a new sample of 52 X-ray selected type-II active galactic nuclei (AGNs). Eighteen of our sources…

We report new observations of molecular oxygen in absorption at z=0.685 in front of the radio source B0218+357. The lines at 56.3 and 118.7 GHz have been observed, redshifted to 33.4 and 70.5 GHz respectively, with the 12m at Kitt Peak, 43m…

A statistical analysis of the space-time distribution of absorption-line systems (ALSs) observed in QSO spectra within the cosmological redshift interval $z$=0.0--3.7 is carried out on the base of our catalog of absorption systems…

We find a bright (L_{UV}=2.5 L*_{z=6}) Lyman alpha emitter at redshift z=5.719 at a projected distance of 79 physical kpc from a strong triply ionized carbon (Civ) absorption system at redshift z=5.7238 previously reported in the spectrum…

Based upon QSO absorption line studies, galaxies at 0.3 < z < 1.0 are seen to have extended gaseous "halos". When the absorption lines are observed at high resolution, the velocity distribution of the absorbing gas gives clues as to where…

Large-scale structure calculations show that modest overdensity filaments will connect clusters of galaxies and these filaments are reservoirs of baryons, mainly in gaseous form. To determine whether such filaments exist, we have examined…

Hydro cosmological simulations reveal that massive galaxies at high redshift are fed by long narrow streams of merging galaxies and a smoother component of cold gas. We post-process seven high-resolution simulated galaxies with radiative…

We present an analysis of the absorption-line system in the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph spectrum at a redshift of $z_{\rm a}={3.1448}$ associated with the quasar SDSS J122040.23+092326.96, whose…

We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6 and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption…

We have obtained optical spectra of four galaxies associated with MgII QSO absorbers at redshifts 0.10 < z < 0.45. We calculate the gas-phase oxygen abundance of these galaxies using the empirical R23 strong line method. The absolute B-band…

We report new HST and ground-based observations of a damped Lyman-alpha absorption system toward the QSO 0850+4400. The redshift of the absorption system is z = 0.163770 and the neutral hydrogen column density of the absorption system is…