  We report R~3000 VLT ISAAC K-band spectroscopy of the nuclei (i.e. central
100-300pc) of 9 galaxies hosting an active galactic nucleus. For 5 of these we
also present spectra of the circumnuclear region out to 1kpc. We have measured
a number of H_2 lines in the v=1-0, 2-1, and 3-2 vibrational transitions, as
well as the Br_gamma and HeI recombination lines, and the NaI stellar
absorption. Although only 3 of the galaxies are classified as Seyfert 1s in the
literature, broad Br_gamma (FWHM 1000kms) is seen in 7 of the objects. The
v=1-0 emission appears thermalised at T~1000K. However, the v=2-1 and 3-2
emission show evidence of being radiatively excited by far-UV photons. The PDR
models that fit the data best are, as for the ultraluminous infrared galaxies
in Davies et al. (2003), those for which the H_2 emission arises in dense
clouds illuminated by intense FUV radiation. The NaI stellar absorption is
clearly seen in 6 of the nuclear spectra, indicating the presence of a
significant population of late type stars. It is possible that these stars are
a result of the same episode of star formation that gave rise to the stars
heating the PDRs. It seems unlikely that the AGN is the dominant source of
excitation for the near infrared H_2 emission: in two nuclei H_2 was not
detected at all, and in general we find no evidence of suppression of the
2-1S(3) line, which may occur in X-ray irradiated gas. Our data do not reveal
any significant difference between the nuclear and circumnuclear line ratios,
suggesting that the physical conditions of the dominant excitation mechanism
are similar both near the AGN and in the larger scale environment around it,
and that star formation is an important process even in the central 100pc
acround AGN.
