Shunsuke BABA

Recent submillimeter observations have revealed signs of pc-scale molecular inflow and atomic outflow in the nearest Seyfert 2 galaxy, the Circinus galaxy. To verify the gas kinematics suggested by these observations, we performed molecular and atomic line transfer calculations based on a physics-based 3D radiation-hydrodynamic model, which has been compared with multi-wavelength observations in this paper series. The major axis position-velocity diagram (PVD) of CO(3–2) reproduces the observed faint emission at the systemic velocity, and our calculations confirm that this component originates from failed winds falling back to the disk plane. The minor-axis PVD of [CI](³P₁–³P₀), when created using only the gas with positive radial velocities, presents a sign of blue- and redshifted offset peaks similar to those in the observation, suggesting that the observed peaks indeed originate from the outflow, but that the model may lack outflows as strong as those in the Circinus galaxy. Similar to the observed HCN(3–2), the similar dense gas tracer HCO⁺(3–2) can exhibit nuclear spectra with inverse P-Cygni profiles with ~0.5 pc beams, but the line shape is azimuthally dependent. The corresponding continuum absorbers are inflowing clumps at 5–10 pc from the center. To detect significant absorption with a high probability, the inclination must be fairly edge-on (≳85°), and the beam size must be small (≲1 pc). These results suggest that HCN or HCO⁺ and [CI] lines are effective for observing pc-scale inflows and outflows, respectively.

We present a new calibration for the second-order light contamination in the near-infrared grism spectroscopy with the Infrared Camera aboard AKARI, specifically for the post-cryogenic phase of the satellite (Phase 3). Following our previous work on the cryogenic phase (Phases 1 and 2), the wavelength and spectral response calibrations were revised. Unlike Phases 1 and 2, during Phase 3 the temperature of the instrument was not stable and gradually increased from 40 to 47 K. To assess the effect of the temperature increase, we divided Phase 3 into three sub-phases and performed the calibrations separately. As in Phases 1 and 2, we confirmed that there was contamination due to the wavelength dependence of the refractive index of the grism material in every sub-phase. The wavelength calibration curves for the three sub-phases coincided with each other and did not show any significant temperature dependence. The response decreased with temperature by ∼10% from the beginning to the end of Phase 3. We approximated the temperature dependence of the response at a linear relation and derived a correction factor as a function of temperature. The relative fraction of the second-order light contamination to the first-order light was found to be 25% smaller than that in Phases 1 and 2.