Seeding the formation of cold gaseous clouds in Milky Way size halos
  We use one of the highest resolution cosmological SPH simulations to date to
demonstrate that cold gaseous clouds form around Milky Way size galaxies. We
further explore mechanisms responsible for their formation and show that a
large fraction of clouds originate as a consequence of late-time filamentary
"cold mode" accretion. Here, filaments that are still colder and denser than
the surrounding halo gas, are not able to connect directly to galaxies, as they
do at high redshift, but are instead susceptible to the combined action of
cooling and Rayleigh-Taylor instabilities at intermediate radii within the halo
leading to the production of cold, dense pressure-confined clouds, without an
associated dark matter component. This process is aided through the compression
of the incoming filaments by the hot halo gas and expanding shocks during the
halo buildup. Our mechanism directly seeds clouds from gas with substantial
local overdensity, unlike in previous models, and provides a channel for the
origin of cloud complexes. These clouds can later "rain" onto galaxies,
delivering fuel for star formation. Owing to the relatively large cross section
of filaments and the net angular momentum carried by the gas, the clouds will
be distributed in a modestly flattened region around a galaxy.
