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ABSTRACT We present the hot molecular and warm ionized gas kinematics for 33 nearby (0.001 ≲ z ≲ 0.056) X-ray selected active galaxies using the H$$_2\, 2.1218\, \mu$$m and Br γ emission lines observed in the K band with the Gemini near-infrared integral field spectrograph. The observations cover the inner 0.04–2 kpc of each active galactic nucleus at spatial resolutions of 4–250 pc with a velocity resolution of σinst ≈ 20 $${\rm km\, s^{-1}}$$. We find that 31 objects (94 per cent) present a kinematically disturbed region (KDR) seen in ionized gas, while such regions are observed in hot molecular gas for 25 galaxies (76 per cent). We interpret the KDR as being due to outflows with masses of 102–107 and 100–104 M⊙ for the ionized and hot molecular gas, respectively. The ranges of mass-outflow rates ($$\dot{M}_{\rm out}$$) and kinetic power ($$\dot{E}_{\rm K}$$) of the outflows are 10−3–101 M⊙ yr−1 and ∼1037–1043 erg s−1 for the ionized gas outflows, and 10−5–10−2 M⊙ yr−1 and 1035–1039 erg s−1 for the hot molecular gas outflows. The median coupling efficiency in our sample is $$\dot{E}_{\mathrm{K}}/L_{\rm bol}\approx 1.8\times 10^{-3}$$ and the estimated momentum fluxes of the outflows suggest they are produced by radiation-pressure in low-density environment, with possible contribution from shocks.
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Unravelling the physics of multiphase AGN winds through emission line tracers
ABSTRACT Observations of emission lines in active galactic nuclei (AGNs) often find fast (∼1000 km s−1) outflows extending to kiloparsec scales, seen in ionized, neutral atomic and molecular gas. In this work we present radiative transfer calculations of emission lines in hydrodynamic simulations of AGN outflows driven by a hot wind bubble, including non-equilibrium chemistry, to explore how these lines trace the physical properties of the multiphase outflow. We find that the hot bubble compresses the line-emitting gas, resulting in higher pressures than in the ambient interstellar medium or that would be produced by the AGN radiation pressure. This implies that observed emission line ratios such as [O iv]$$_{25 \, \rm {\mu m}}$$ / [Ne ii]$$_{12 \, \rm {\mu m}}$$, [Ne v]$$_{14 \, \rm {\mu m}}$$ / [Ne ii]$$_{12 \, \rm {\mu m}}$$, and [N iii]$$_{57 \, \rm {\mu m}}$$ / [N ii]$$_{122 \, \rm {\mu m}}$$ constrain the presence of the bubble and hence the outflow driving mechanism. However, the line-emitting gas is under-pressurized compared to the hot bubble itself, and much of the line emission arises from gas that is out of pressure, thermal and/or chemical equilibrium. Our results thus suggest that assuming equilibrium conditions, as commonly done in AGN line emission models, is not justified if a hot wind bubble is present. We also find that ≳50 per cent of the mass outflow rate, momentum flux, and kinetic energy flux of the outflow are traced by lines such as [N ii]$$_{122 \, \rm {\mu m}}$$ and [Ne iii]$$_{15 \, \rm {\mu m}}$$ (produced in the 10$$^{4} \, \rm {K}$$ phase) and [C ii]$$_{158 \, \rm {\mu m}}$$ (produced in the transition from 10$$^{4} \, \rm {K}$$ to 100 K).
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- Award ID(s):
- 1652522
- PAR ID:
- 10278882
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 503
- Issue:
- 2
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- 1568 to 1585
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/mnras/stab556
