The Galaxy Activity, Torus, and Outflow Survey (GATOS) II. Torus and polar dust emission in nearby Seyfert galaxies

Alonso-Herrero, A.; Garcia-Burillo, S.; Honig, S. F.; Garcia-Bernete, I; Ramos Almeida, C.; Gonzalez-Martin, O.; Lopez-Rodriguez, E.; Boorman, P. G.; Bunker, A. J.; Burtscher, L.; Combes, F.; Davies, R.; Diaz-Santos, T.; Gandhi, P.; Garcia-Lorenzo, B.; et. al.

Abstract

We compare high angular resolution mid-infrared (mid-IR) and Atacama Large Millimeter/submillimeter Array (ALMA) far-infrared (far-IR) images of twelve nearby (median 21 Mpc) Seyfert galaxies selected from the Galaxy Activity, Torus, and Outflow Survey (GATOS). The mid-IR unresolved emission contributes more than 60% of the nuclear (diameters of 1.5 ''similar to 150 pc) emission in most galaxies. By contrast, the ALMA 870 mu m continuum emission is mostlyresolved with a median diameter of 42 pc and typically along the equatorial direction of the torus (Paper I). The Eddington ratios and nuclear hydrogen column densities (N-H) of half the sample are favorable to launching polar and/or equatorial dusty winds, according to numerical simulations. Six of these show mid-IR extended emission approximately in the polar direction as traced by the narrow line region and perpendicular to the ALMA emission. In a few galaxies, the nuclear N-H might be too high to uplift large quantities of dusty material along the polar direction. Five galaxies have low N-H and/or Eddington ratios and thus polar dusty winds are not likely. We generated new radiative transfer CAT3D-WIND disk+wind models and model images at 8, 12, and 700 mu m. We tailored these models to the properties of the GATOS Seyferts in this work. At low wind-to-disk cloud ratios, the far-IR model images have disk- and ring-like morphologies. The characteristic "X"-shape associated with dusty winds is seen better in the far-IR at intermediate-high inclinations for the extended-wind configurations. In most of the explored models, the mid-IR emission mainly comes from the inner part of the disk and cone. Extended biconical and one-sided polar mid-IR emission is seen in extended-wind configurations and high wind-to-disk cloud ratios. When convolved to the typical angular resolution of our observations, the CAT3D-WIND model images reproduce qualitative aspects of the observed mid- and far-IR morphologies. However, low to intermediate values of the wind-to-disk ratio are required to account for the observed large fractions of unresolved mid-IR emission in our sample. This work and Paper I provide observational support for the torus+wind scenario. The wind component is more relevant at high Eddington ratios and/or active galactic nucleus luminosities, and polar dust emission is predicted at nuclear column densities of up to similar to 10(24) cm(-2). The torus or disk component, on the other hand, prevails at low luminosities and/or Eddington ratios.

Más información

Título según WOS: The Galaxy Activity, Torus, and Outflow Survey (GATOS) II. Torus and polar dust emission in nearby Seyfert galaxies
Título de la Revista: ASTRONOMY & ASTROPHYSICS
Volumen: 652
Editorial: EDP SCIENCES S A
Fecha de publicación: 2021
DOI:

10.1051/0004-6361/202141219

Notas: ISI