July 20, 2004 Resolving the 'missing satellites problem' by Andrey Kravtsov
Resolving the 'missing satellites problem'
A generic prediction of the standard galaxy formation paradigm is that dark matter halos are "lumpy", filled with hundreds of dense, gravitationally bound clumps of dark matter. The abundance of these clumps is much larger than the typical number of dwarf satellites around galactic halos --- the discrepancy often called "the missing satellites problem". KICP member Andrey Kravtsov and his collaborators proposed a solution to the missing satellites problem based on the observations that dwarf galaxy size objects in numerical simulations often undergo dramatic mass evolution.
In general, astrophysicists believe that formation of very small dwarf galaxies should be suppressed. This is because gas required for continued formation of stars can be heated and expelled by the first generation of exploding supernovae stars. In addition, ultraviolet radiation from galaxies and quasars that began to fill the universe approximately 12 billion years ago heats the intergalactic gas, shutting down the supply of fresh gas to dwarf galaxies. Andrey Kravtsov found that some of the dwarf galaxies that are small today have been more massive in the past and could gravitationally collect the gas they need to form stars and become a galaxy. The result puts the cold dark matter scenario on more solid ground.