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To investigate the origins of the warm absorbers in active galactic nuclei(AGNs), we study the ionization-state structure of the radiation-drivenfountain model in a low-mass AGN (Wada et al. 2016) and calculate the predictedX-ray spectra, utilizing the spectral synthesis code Cloudy (Ferland et al.2017). The spectra show many absorption and emission line features originatedin the outflowing ionized gas. The O VIII 0.654 keV lines are produced mainlyin the polar region much closer to the SMBH than the optical narrow lineregions. The absorption measure distribution of the ionization parameter($\xi$) at a low inclination spreads over 4 orders of magnitude in $\xi$,indicating multi-phase ionization structure of the outflow, as actuallyobserved in many type-1 AGNs. We compare our simulated spectra with the highenergy-resolution spectrum of the narrow line Seyfert 1 galaxy, NGC 4051. Themodel reproduces slowly outflowing (a few hundreds km s$^{-1}$) warm absorbers.However, the faster components with a few thousands km s$^{-1}$ observed in NGC4051 are not reproduced. The simulation also underproduces the intensity andwidth of the O VIII 0.654 keV line. These results suggest that the ionized gaslaunched from sub-parsec or smaller regions inside the torus, which are notincluded in the current fountain model, must be important ingredients of thewarm absorbers with a few thousands km s$^{-1}$. The model also consistentlyexplains the Chandra/HETG spectrum of the Seyfert 2 galaxy, the Circinusgalaxy.

Warm Absorbers in the Radiation-driven Fountain Model of Low-mass Active Galactic Nuclei