Martin Haehnelt

MPA-Garching

Cosmology with the Lyman alpha forest

In the last few years a new paradigm for the origin of the Lyman 
alpha forest in the spectra of distant QSO's has been established
by both new observations and numerical simulations. The Lyman
alpha forest  is now generally believed to  arise from fluctuations 
in a warm (10^4 K) photoionized intergalactic medium which traces the
large scale distribution of dark matter  in a simple fashion. I discuss 
some of the exiting new possibilities to probe the distribution of dark 
matter, to constrain cosmological parameters and to investigate the 
thermal and metal enrichment history of the intergalactic medium.