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arXiv · 2104.03105

The AGNIFS survey: distribution and excitation of the hot molecular and ionised gas in the inner kpc of nearby AGN hosts

R. A. Riffel·T. Storchi-Bergmann·R. Riffel·M. Bianchin·N. L. Zakamska·D. Ruschel-Dutra·A. J. Schonell·D. J. Rosario·A. Rodriguez-Ardila·T. C. Fischer·R. I. Davies·N. Z. Dametto·L. G. Dahmer-Hahn·D. M. Crenshaw·L. Burtscher·M. C. Bentz
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Abstract

We use the Gemini NIFS instrument to map the H$_2 2.1218\mu$m and Br$\gamma$ flux distributions in the inner 0.04-2 kpc of a sample of 36 nearby active galaxies ($0.001\lesssim z\lesssim0.056$) at spatial resolutions from 4 to 250 pc. We find extended emission in 34 galaxies. In $\sim$55% of them, the emission in both lines is most extended along the galaxy major axis, while in the other 45% the extent follows a distinct orientation. The emission of H$_2$ is less concentrated than that of Br$\gamma$, presenting a radius that contains half of the flux 60% greater, on average. The H$_2$ emission is driven by thermal processes - X-ray heating and shocks - at most locations for all galaxies, where $0.4 6$ (seen in 40% of the galaxies), shocks are the main H$_2$ excitation mechanism, while in regions with H$_2$/Br$\gamma<0.4$ (25% of the sample) the H$_2$ emission is produced by fluorescence. The only difference we found between type 1 and type 2 AGN was in the nuclear emission-line equivalent widths, that are smaller in type 1 than in type 2 due to a larger contribution to the continuum from the hot dusty torus in the former. The gas masses in the inner 125 pc radius are in the range $10^1-10^4$ M$_\odot$ for the hot H$_2$ and $10^3-10^6$ M$_\odot$ for the ionised gas and would be enough to power the AGN in our sample for $10^5-10^8$ yr at their current accretion rates.

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R. A. Riffel, T. Storchi-Bergmann, R. Riffel, M. Bianchin, N. L. Zakamska, D. Ruschel-Dutra, A. J. Schonell, D. J. Rosario, A. Rodriguez-Ardila, T. C. Fischer, R. I. Davies, N. Z. Dametto, L. G. Dahmer-Hahn, D. M. Crenshaw, L. Burtscher, M. C. Bentz. 2021-04-07. The AGNIFS survey: distribution and excitation of the hot molecular and ionised gas in the inner kpc of nearby AGN hosts. https://doi.org/10.1093/mnras/stab998

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