2025PASP..137f4104K -
Publ. Astron. Soc. Pac., 137, part no 6, 4104 (2025/June-0)
A Hydrodynamical Thermal Irradiated Wind from the Outer Thin Accretion Disk in Low-luminosity Active Galactic Nuclei.
KUMAR N.
Abstract (from CDS):
Evidently, low-luminosity active galactic nuclei (LLAGNs) are comprised of an inner advective disk and an outer geometrically thin disk. Wind is inevitable in LLAGNs, mainly interpreted in an indirect way; also, the evidence is growing for the presence of wind in the outer thin disk. We present a hydrodynamics (HD) model for wind from the outer thin disk, where the main driver is the inner disk irradiation (which is parameterized by a number x in hydrostatic equilibrium equation) and the heating mechanism is photoionization. The model works for low-intensity irradiation or from a height zs in the optically thin medium. We solve the model equations in cylindrical coordinates along the z-axis for a given radius r assuming a tiny vertical speed vz (≪cs sound speed). The sonic point conditions assure an isobaric regime above the sonic height (${z}^{{\rm{\max }}}$); in addition to the height ${z}_{f}(\ll {z}^{{\rm{\max }}}$), the radial pressure gradient also supports the fluid rotation, and both jointly assure a wind ejection from the ${z}^{{\rm{\max }}}$ with fluid speed. The ${z}^{{\rm{\max }}}$ increases with x, and beyond a large ${z}^{{\rm{\max }}}$ (say ${z}_{t}^{{\rm{\max }}}$ corresponding to maximum x), there is no physical solution. We start the computation from the outer radius ${r}_{o}^{{\rm{thin}}}$ to the inner ${r}_{{\rm{in}}}^{{\rm{thin}}}$ with a Bondi mass accretion rate ${\dot{M}}_{{\rm{Bondi}}}$ to explore the r dependency of the mass inflow rate $\dot{M}$ and wind properties. We constrain the model by fixing $\dot{M}$ at ${r}_{{\rm{in}}}^{{\rm{thin}}}$ from the observations of NGC 1097 and check the feasibility of the model by comparing the energetics with the observed bolometric luminosity. The wind is equatorial with a viewing angle i > 85° and capable of generating red/blueshifted lines, which would be a general characteristics for LLAGNs.
Abstract Copyright:
© 2025. The Astronomical Society of the Pacific. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Journal keyword(s):
Accretion - Stellar accretion - Hydrodynamics - Stellar winds - Low-luminosity active galactic nuclei
Simbad objects:
6
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