Tom Theuns
Dept. Physics, Univ. Durham (Durham, Grande Bretagne)
Salle Entresol Daniel Chalonge, Institut d'Astrophysique de Paris
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| « Numerical simulations of the intergalactic medium » |
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Tom Theuns |
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The intergalactic medium produces hundreds of absorption lines in the spectra of background quasars. Numerical simulations reproduce the statistical properties of these lines relatively well, and show that most lines are formed in the mildly over dense filaments of the cosmic web. These structures can be reliably simulated because of their modest densities, and comparison with the superb data from VLT/UVES, Keck/HiRes, and the SDDS quasar sample, allows one to constrain the evolution of the intergalactic medium. I will describe the simulation technique and underlying assumptions, and concentrate on evidence that HeII reionized around redshift 3.5. The spectra also contain stronger lines, which are usually associated with metal transitions as well. In simulations, these lines invariably form in proto-haloes, and I will describe preliminary results, suggesting they could be an excellent tool to study galaxy formation at high redshift.
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vendredi 31 janvier 2003 - 11:00 Salle Entresol Daniel Chalonge, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |