activity
19952000
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astro-ph2000

Constraining reionization using the thermal history of the baryons

Joop Schaye, Tom Theuns, Michael Rauch +2

The thermal evolution of the intergalactic medium (IGM) depends on the reionization history of the universe. Numerical simulations indicate that the low density IGM, which is respo…

astro-ph1998

Glimpses of the Interstellar Medium at Redshift 3.5

Michael Rauch, Wallace L. W. Sargent, Thomas A. Barlow

We have obtained high resolution (FWHM = 4.4 km/s) Keck spectra of images A and C of the gravitationally lensed QSO Q1422+231. The images are separated by 1.3" on the sky. In an ab…

astro-ph1998

Metallic Absorbers and the Evolution of Galaxy Haloes and the Metagalactic Ionizing Background

Alec Boksenberg, Wallace L. W. Sargent, Michael Rauch

An extremely careful separation of the weak metal-line systems relating to the Lyman forest absorbers into individual ``single-phase ionization'' components with accurate parameter…

astro-ph1998

The Metal Contents of Very Low Column Density Lyman-alpha Clouds: Implications for the Origin of Heavy Elements in the Intergalactic Medium

Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow +1

We investigate the metal contents of Lyman-alpha clouds at 2.2<z<3.6 with 10^13.5<N(HI)<10^14 cm-2 using high resolution, high S/N spectra of 9 quasars obtained with the 10m Keck I…

astro-ph1997

Small Scale Structure in the Universe and the Distribution of Baryons at High Redshift

Michael Rauch

We briefly discuss the relevance of Lyman alpha forest observations for measuring cosmological parameters, comparing the properties of high z QSO spectra with those of artifical sp…

astro-ph1995

The metal line systems in HS1700+6416: Evidence for inhomogeneities

Patrick Petitjean, Ruediger Riediger, Michael Rauch

We present a high S/N ratio optical spectrum of the bright quasar HS1700+6416. These data usefully complement the UV HST data from Vogel and Reimers (1995). We analyse the metal li…