Near Field Cosmology on the Computer

Speaker:Professor Yehuda Hoffman
Affiliation:The Hebrew University, Physics
Location:Lidow Rosen Auditorium (323)

The modus operandi of cosmology is the study of universe on the largest possible scales and the longest look-back times. However, the further out one observers and hence the greater is the look-back time to the observed object, the more difficult  observations get. This has led astronomers to look for hints for the formation and evolution of galaxies in our own backyard, mostly within the Local Group (LG), which is dominated by our host galaxy the Milky Way and the Andromeda galaxies, resulting in the so-called  ’Near Field Cosmology’.  It follows that the near field cosmologist acts as an archeologist who digs in the multi-dimensional phase space of the stellar population looking for clues for the formation and mass assembly history of the LG.  The relevance of the study of the local universe to cosmology at large depends on the Copernican assumption that we are living in a typical patch of the universe. To what extent this assumption is valid? The Constrained Local UniversE Simulations (CLUES) project provides a numerical laboratory for addressing this fundamental issue. A variety of galaxy formation issues studied under the CLUES umbrella  will be presented. This includes the "cosmic web stripping" of small mass halos of their gas as they pass through filaments and pancakes. This newly identified process alleviates the problem of the  scarcity of dwarf galaxies compared with the numerous low-mass halos expected in the current ΛCDM paradigm.