摘要：Context. The H i halo clouds of the Milky Way, and in
particular the intermediate-velocity clouds (IVCs), are thought to be connected to
Galactic fountain processes. Observations of fountain clouds are important for
understanding the role of matter recycling and accretion onto the Galactic disk and
subsequent star formation.
Aims. Here, we quantify the amount of molecular gas in the Galactic
halo. We focus on the rare class of molecular IVCs (MIVCs) and search for new objects.
Methods. The H i-FIR correlation was studied across the entire
northern and southern Galactic hemispheres at Galactic latitudes | b | > 20° to determine
the amount and distribution of molecular gas in IVCs. We used the most recent large-scale
H i and FIR data, the Effelsberg Bonn-H i Survey, the Parkes Galactic
All-Sky Survey, and the Planck FIR surveys.
Results. We present a catalogue of 239 MIVC candidates on the northern
and southern Galactic hemispheres. Among these candidates, all previously known MIVCs are
recovered except for one single source. The frequency of candidates differs significantly
between the northern and southern Galactic hemispheres and between negative and positive
LSR velocities as well.
Conclusions. In our approach we analyse the local Galactic environment.
Extrapolating our results to the entire Galaxy, the global inflow of atomic and molecular
IVC gas onto the Milky Way may account for the major fraction of the gaseous mass that is
required to sustain the current Galactic star formation rate.
