SIMBAD references

2026ApJ...999..185T - Astrophys. J., 999, 185 (2026/March-2)

ALMA [C I] Image of the Circumnuclear Disk of the Milky Way: Inflowing Low-density Molecular Gas.

TANAKA K., NAGAI M. and KAMEGAI K.

Abstract (from CDS):

We present Atacama Large Millimeter/submillimeter Array [C I] 3P1-3P0 imaging of the central 6.6 × 4.2 pc2 region of the Galaxy encompassing the circumnuclear disk (CND). The data reveal low-density (${n}_{{{\rm{H}}}_{2}}\sim 1{0}^{3}\,$cm–3) molecular gas with inward motion, widespread both inside and outside the CND. The normalized [C I] to CS 7-6 intensity difference decreases inwardly from R = 4 pc to 1.7 pc and azimuthally along the CND's rotation, likely tracing paths of low-density gas inflow. By projecting spaxels into orbital coordinates assuming a velocity field model, we identify four kinematic features: a pair of spiral outer streamers toward the CND, inner streamers extending to 0.5 pc from Sgr A*, an outer disk at R ∼ 3-6 pc, and the rotating ring at R = 2 pc. P-P-V correlation between the inner streamers and H42α indicates gas supply to the mini-spiral through the western arc (WA) and northern arm (NA). The total inflowing mass is 1.5 × 104M⊙, 1.7 times the mass of the rotating ring. The identified flows can be organized into two main pathways connecting the CND exterior and interior: “WA flow” feeding the mini-spiral WA via the CND, and “NA flow” bypassing the purely rotating orbit. The inflow rate along the former is approximately constant (0.1-0.16 M⊙ yr–1), implying a CND dwelling time comparable to its orbital period and supporting the CND's transient nature. We also identify two [C I]-bright clumps (CBCs) lacking dense-gas counterparts near the contact point between the northern outer streamer and the CND. Apparently intact against tidal disruption despite subcritical densities, the CBCs may represent a chemically young phase shortly after formation in colliding flows.

Abstract Copyright: © 2026. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Molecular clouds - Galactic center - Galaxy circumnuclear disk

Simbad objects: 6

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