اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدStudy of the inner structure of the molecular torus in IRAS 08572+3915 NW with velocity decomposition of CO ro-vibrational absorption lines
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Understanding the inner structure of the clumpy molecular torus surrounding the active galactic nucleus is essential in revealing the forming mechanism. However, spatially resolving the torus is difficult because of its size of a few parsecs. Thus, to probe the clump conditions in the torus, we performed the velocity decomposition of the CO ro-vibrational absorption lines ($Delta{v}=0to 1, Delta{J}=pm 1$) at $lambdasim 4.67 mathrm{mu{m}}$ observed toward an ultra-luminous infrared galaxy IRAS 08572+3915 NW with the high-resolution spectroscopy ($Rsim 10000$) of Subaru Telescope. Consequently, we found that each transition had two outflowing components, i.e., (a) and (b), both at approximately $sim -160 mathrm{km s^{-1}}$, but with broad and narrow widths, and an inflowing component, i.e., (c), at approximately $sim +100 mathrm{km s^{-1}}$, which were attributed to the torus. The ratios of the velocity dispersions of each component lead to those of the rotating radii around the black hole of $R_mathrm{rot,a}:R_mathrm{rot,b}:R_mathrm{rot,c}approx 1:5:17$, indicating the torus where clumps are outflowing in the inner regions and inflowing in the outer regions if a hydrostatic disk with $sigma_Vpropto R_mathrm{rot}^{-0.5}$ is assumed. Based on the kinetic temperature of components (a) and (b) of $sim 720 mathrm{K}$ and $sim 25 mathrm{K}$ estimated from the level population, the temperature gradient is $T_mathrm{kin}propto R_mathrm{rot}^{-2.1}$. Magnetohydrodynamic models with large density fluctuations of two orders of magnitude or more are necessary to reproduce this gradient.
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