6 papers · 1 filter
A High Deuterium Abundance at z=0.7; Evidence for Cosmic Inhomogeneity?
J. K. Webb, R. F. Carswell, K. M. Lanzetta +3
Recent HST/GHRS observations of the z = 0.7010 absorber toward the QSO 1718+4807 (selected because of apparently ideal characteristics for measuring D/H) yield a D/H significantly…
Limits on the Variability of Physical Constants
M. J. Drinkwater, J. K. Webb, J. D. Barrow +1
We have compared the frequency of high-redshift Hydrogen HI 21 cm absorption with that of associated molecular absorption in two quasars to place new (1 sigma) upper limits on any…
The Gaseous Extent of Galaxies and the Origin of \lya Absorption Systems at z < 1
H. -W. Chen, K. M. Lanzetta, J. K. Webb +1
We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies in fields of HST spectroscopic target QSOs. The goal of the program is to investigate how…
The Galaxy-Absorber Cross-Correlation Function
Kenneth M. Lanzetta, John K. Webb, Xavier Barcons
We describe an analysis of the galaxy-absorber cross-correlation function as a function of velocity separation, impact parameter separation, and absorber Lyman alpha equivalent wid…
Lyman-alpha absorbers arising in galaxy clusters
A. Ortiz-Gil, K. M. Lanzetta, J. K. Webb +1
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 identifi…
Structure in the Lyman-Alpha Forest
J. Liske, J. K. Webb
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 <…