Avishai Dekel
Hebrew Univ. (Jerusalem, Israël)
According to the emerging picture, the evolution of the high-redshift galaxies is driven by cold streams from the cosmic web. The dense gaseous disks that form in the dark-halo centers fragment into giant clumps due to wild gravitational instability, and the star formation rate in these clumps follows the high accretion rate. Clump migration in the disk, combined with merging clumps that come with the streams, lead to the formation of a central bulge. The system of disk and bulge remains in a steady state for a few Gyr, in which the disk gas is consumed into stars and flows into the bulge while it is replenished by newly accreted gas. The cold streams may be detected as Lyman-alpha blobs. Open questions will be discussed.
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris