Oral Presentation

Study of dense gas around AGN in the nearby Seyfert galaxy NGC 1068

Author(s): Yumi Watanabe(Fukushima University/NAOJ)

Presenter: Yumi Watanabe (Fukushima University/NAOJ)

We focus on the effect of active galactic nuclei (AGN) on interstellar matter to understand galaxy evolution. The dense gas tracer HCN(J=1-0) and molecular gas tracer CO(J=1-0) have been commonly used to study the physics of molecular gas around AGN. We observed the nearby Seyfert galaxy NGC 1068 to study dense gas around the AGN. NGC 1068 has a circumnuclear disk (CND) (radius ~0.2 kpc) surrounding the AGN. The HCN/CO intensity ratio map of NGC 1068 with the highest resolution (60 pc) and highest sensitivity compared to previous studies was created. The HCN/CO intensity ratio was higher than the typical value of 0.1 (e.g., Casasola et al. 2011) not only for the CND but also for 0.3 kpc outside of the CND.
Anomalous excitation or anomalous abundances are one of the likely causes. The excitation anomaly could be a maser, but no sign of it was obtained from the spectra.