Temperature Evolution of Molecular Clouds in the Central Molecular Zone
  We infer the absolute time dependence of kinematic gas temperature along a
proposed orbit of molecular clouds in the Central Molecular Zone (CMZ) of the
Galactic Center (GC). Ammonia gas temperature maps are one of the results of
the "Survey of Water and Ammonia in the Galactic Center" (SWAG, PI: J. Ott);
the dynamical model of molecular clouds in the CMZ was taken from Kruijssen et
al. (2015). We find that gas temperatures increase as a function of time in
both regimes before and after the cloud passes pericenter on its orbit in the
GC potential. This is consistent with the recent proposal that pericenter
passage triggers gravitational collapse. Other investigated quantities (line
width, column density, opacity) show no strong sign of time dependence but are
likely dominated by cloud-to-cloud variations.
