  We demonstrate buffer-gas cooling, high-resolution spectroscopy and cycling
fluorescence of cold barium monofluoride (BaF) molecules. Our source produces
an intense and internally cold molecular beam containing the different BaF
isotopologues with a mean forward velocity of 190 m/s. For a well-collimated
beam of 138BaF we observe a flux of more than 1e10 molecules/sr/pulse in the
X2Sigma, N=1 state in our downstream detection region. Studying the absorption
line strength of the intermediate A'Delta state we infer a lifetime of
790+\-346 ns, significantly longer than previously estimated. Finally,
highly-diagonal Franck-Condon factors and magnetic remixing of dark states
allow us to realize a quasi-cycling transition in 138BaF that is suitable for
future laser cooling of this heavy diatomic molecule.
