The Origin of Two Galaxy Types
Racah Institute of Physics, The Hebrew University of Jerusalem
The emergence of a concordance cosmological model based on cold dark matter and dark energy has triggered a new phase in the study of galaxy formation, in which the framework is known. A flood of multi-wavelength data from space and ground telescopes is revolutionizing our knowledge of axies,
both today and in the distant past, introducing interesting theoretical
challenges. This talk will address the fundamental question of physical
cosmology: the origin of the two major types of galaxies. One population
is the ``blue cloud" of star-forming disk galaxies in the field
and the other is the ``red sequence" of dead ellipticals in clusters.
We will explain the origin of the characteristic mass separating these
populations, and address the main physical processes responsible for the
properties of the two galaxy types.