Direct Evidence of Cold Gas in DLA 0812+32B (2009)
Jorgenson, Regina A., Wolfe, Arthur M., Prochaska, J. Xavier, Carswell, Robert F.
We present the first direct evidence for cold gas in a high redshift DLA galaxy. We measured several multiplets of weak neutral carbon (CI) transitions in order to perform a curve of growth analysis....
Stringent null constraint on cosmological evolution of the proton-to-electron mass ratio (2008)
King, Julian A., Webb, John K., Murphy, Michael T., Carswell, Robert F.
We present a strong constraint on variation of the proton-to-electron mass ratio, mu, over cosmological time scales using molecular hydrogen transitions in optical quasar spectra. Using high quality...
Stringent null constraint on cosmological evolution of the proton-to-electron mass ratio (2008)
King, Julian A., Webb, John K., Murphy, Michael T., Carswell, Robert F.
We present a strong constraint on variation of the proton-to-electron mass ratio mu over cosmological time scales using molecular hydrogen transitions in optical quasar spectra. Using high quality...
Schaye, Joop, Carswell, Robert F., Kim, Tae-Sun
We carried out a survey for high-metallicity C IV absorbers at redshift z ~ 2.3 in the spectra of 9 high-quality quasar spectra. Using a novel analysis technique, based on detections of C IV lines...
Spatial fluctuations in the spectral shape of the UV background at 2 (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Carswell, Robert F.
The low density hydrogen and helium in the IGM probed by QSO absorption lines is sensitive to the amplitude and spectral shape of the metagalactic UV background. We use realistic HI and HeII Ly-alpha...
Cosmological Evolution of Heavy Element and Molecular Hydrogen Abundances (2003)
Curran, Stephen J., Webb, John K., Murphy, Michael T., Carswell, Robert F.
Spectroscopic observations of distant quasars have resulted in the detection of molecular hydrogen in intervening damped Lyman-alpha absorption clouds (DLAs). We use observations compiled from...
The Deuterium Abundance in the z=0.7 absorber towards QSO PG1718+4807 (2003)
Crighton, Neil H. M., Webb, John K., Carswell, Robert F., Lanzetta, Ken M.
We report a further analysis of the ratio of deuterium to hydrogen (D/H) using HST spectra of the z=0.701 Lyman limit system towards the QSO PG1718+481. Initial analyses of this absorber found it...
Tzanavaris, Panayiotis, Carswell, Robert F.
A new analysis of Keck/HIRES observations of the broad absorption line QSO APM 0827+5255 indicates that a number of intervening C IV absorbers give rise to absorption lines for which the observed...
Galactic winds in the intergalactic medium (2002)
Theuns, Tom, Viel, Matteo, Kay, Scott, Schaye, Joop, Carswell, Robert F., Tzanavaris, Panayiotis
We have performed hydrodynamical simulations to investigate the effects of galactic winds on the high-redshift (z=3) universe. Strong winds suppress the formation of low-mass galaxies significantly,...
The physical properties of the Ly-Alpha forest at z > 1.5 (2002)
Kim, Tae-Sun, Carswell, Robert F., Cristiani, Stefano, D'Odorico, Sandro, Giallongo, Emanuele
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...
Carswell, Robert F., Schaye, Joop, Kim, Tae-Sun
A search for O VI at redshifts corresponding to Ly-alpha lines in the z_em ~ 2.4 QSOs HE1122-1648 and HE2217-2818 reveals that a substantial fraction of those with H I column densities log N(HI) > 14...
Temperature fluctuations in the intergalactic medium (2001)
Theuns, Tom, Zaroubi, Saleem, Kim, Tae-Sun, Tzanavaris, Panayiotis, Carswell, Robert F.
The temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. We have...
Rauch, Michael, Sargent, Wallace L. W., Barlow, Thomas A., Carswell, Robert F.
Spectra from the Keck HIRES instrument of the Lyman alpha forests in the lines of sight to the A and C components of the gravitationally lensed QSO Q1422+231 were used to investigate the structure of...
New HST spectra indicate the QSO PG1718+4807 will not give the primordial deuterium abundance (2001)
Kirkman, David, Tytler, David, O'Meara, John M., Burles, Scott, Lubin, Dan, Suzuki, Nao, ...
The z ~ 0.701 absorption system towards the QSO PG1718+4807 is the only example of a QSO absorption system which might have a deuterium/hydrogen ratio approximately ten times the value found towards...
Mapping Low-Density Intergalactic Gas: a Third Helium Lyman-alpha Forest (1998)
Anderson, Scott F., Hogan, Craig J., Williams, Benjamin F., Carswell, Robert F.
We present a new HST/STIS spectrum of the z=3.18 quasar PKS 1935-692 and summarize the spectral features shortwards of 304A in the rest frame likely to be caused by foreground HeII Lyman-alpha...