Multi-molecule ALMA observations towards the Seyfert 1 galaxy NGC 1097
  The nearby Sy 1 galaxy NGC 1097 represents an ideal laboratory to explore the
molecular chemistry in the presence and surroundings of an active galactic
nucleus. Exploring the distribution of different molecular species allows us to
understand the physical processes affecting the ISM both in the AGN vicinity as
well as in the outer star forming molecular ring. We carried out 3 mm ALMA
observations of HCN, HCO+, CCH, CS, HNCO, SiO, HC3N, and SO as well as the 13C
isotopologues. All species were imaged over the central 2 kpc (~30") of the
galaxy at a resolution of ~2.2"x1.5 (150 pc x 100 pc). HCO+ and CS appear to be
slightly enhanced in the star forming ring. CCH, showing the largest variations
across NGC 1097, is suggested to be a good tracer of both obscured and early
stage star formation. HNCO, SiO and HC3N are significantly enhanced in the
inner circumnuclear disk surrounding the AGN. Differences in the molecular
abundances are observed between the star forming ring and the inner
circumnuclear disk. We conclude that the HCN/HCO+ and HCN/CS differences
observed between AGN dominated and starburst galaxies are not due to a HCN
enhancement due to X-rays, but rather this enhancement is produced by shocked
material at distances of 200 pc from the AGN. Additionally we claim the lower
HCN/CS to be a combination of a small under-abundance of CS in AGNs together
with excitation effects, where a high dense gas component (~10^6 cm^-3) may be
more prominent in SB galaxies. However the most promising are the differences
found among the dense gas tracers which, at our modest spatial resolution, seem
to outline the physical structure of the molecular disk around the AGN. In this
picture, HNCO probes the well shielded gas in the disk, surrounding the dense
material moderately exposed to X-ray radiation traced by HC3N. Finally SiO
might be the innermost molecule in the disk structure.
