Patrick Valageas web page

The IGM (i.e. the intergalactic medium which extends between galaxies to form large under-dense regions or filaments) occupies most of the volume of the universe and makes up a significant fraction of its mass. Therefore it is one of the main components of our universe. This diffuse medium exhibits non-negligible density fluctuations which show up as Lyman-alpha absorption lines on the spectra of the light we receive from distant quasars. These lines are thus associated with "Lyman-alpha" clouds. This medium is easier to describe than galaxies because star formation does not play a direct role.

Articles:

• 2002, A&A, 388, 741
  An analytical model to describe the phase-diagram (density-temperature) of the intergalactic medium and its various properties.
  
• 2001, A&A, 366, 363
  An analytical description of the relationship between the distributions of dark matter matter and baryons: bias of various objects (clusters, galaxies, quasars, Lyman-alpha clouds).
  
• 1999, A&A, 345, 691
  An analytical model for a detailed description of Lyman-alpha clouds.