Speaker
Description
"Active galactic nuclei (AGN) are among the most energetic phenomena in the universe and play a fundamental role in galaxy evolution. The unified model of AGN has been widely accepted as an explanation for the diverse properties of AGNs. Recent mid-infrared observations have revealed a very compact (~1 pc), hot (>700 K), and optically thick dust ring that likely obscures the central engine of NGC 1068, a Type-II Seyfert galaxy. However, the full picture remains unclear due to the lack of spatially resolved observations of the substantial cold-to-warm gas and dust disks.
Here, we present initial results from ALMA Band 8-9 observations of the AGN in NGC 1068 with a spatial resolution down to 2-4 pc. We detected disk-like gas structures (r ~ 10 pc) around the AGN in CO(5-4) and CO(6-5). In contrast, the Band 8-9 continuum emission was detected not as an extended structure but as a compact component (r < 5 pc) centered at the AGN. Super-resolution reimaging further suggests an even more compact component (r < 2 pc), comparable to the mid-infrared hot dust ring. Radio-to-infrared spectral energy distribution (SED) fitting indicates that the continuum emission primarily arises from a combination of synchrotron radiation scattered by plasma (50-30%) and warm dust emission (50-70%) in Band 8-9. These findings suggest a different picture from the current torus model, where the submillimeter continuum emission may originate from compact warm dust coexisting with the hot dust in the torus and/or a much more compact source such as synchrotron emission from coronal gas."
