Three-Dimensional Structure of the Central Molecular Zone

Abstract

A detailed comparison of HI and CO line cube data of the Galactic Center (GC) region from the archives is obtained. The central molecular zone (CMZ) is shown to be embedded in the HI disc (central HI zone, CHZ) of radius $\sim 320$ pc and vertical scale height $\sim 70$ pc. A radio continuum belt is shown to run parallel to molecular Arms I and II. The belt draws a double-infinity shape on the sky, connecting Sgr E ($l\sim -1^{\circ }.2)$, C, B1, B2 and Sgr D ($+1^{\circ }.2$), and is interpreted as a warping star-forming ring. The molecular Arms are closely associated with the HI arms on the longitude-velocity diagram (LVD), showing coherent rigid-body ridges. Due to the close relationship between HI and CO, the HI line absorption can be used to determine the Arms' position relative to Sgr A, B1, B2 and C.Combining the trigonometric data of proper motions of Sgr A${}^{\ast }$ and maser sources of Sgr B2 as well as radial velocities, the 3D velocity vector of Sgr B2 is determined. From these analyses, the molecular Arm I with Sgr B2 is shown to be located in the near side of Sgr A${}^{\ast }$, and Arm II with Sgr C in the other side, both composing a pair of symmetrical Arms around the GC. We present a possible 3D view of Sgr A through E and Arms I and II along with a parameter list.

arXiv commentAccepted for MNRAS, 19 pages, 12 figures

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Cited by in corpus (7)

• 3-D CMZ IV: Distinguishing Near vs. Far Distances in the Galactic Center Using Spitzer and Herschel
• Supernova-remnant origin of the Galactic-Centre filaments
• Modeling the Galactic center gamma-ray emission with more realistic cosmic-ray dynamics
• Gas Dynamics in the Central Molecular Zone and its connection with the Galactic Bar
• Cosmic rays, gas and dust in the Central Molecular Zone I -- $X_{CO}$ factors, cosmic-ray densities and dust opacities
• Parabolic-like Trend in SiO Ratios throughout the Central Molecular Zone: Possible Signature of a Past Nuclear Activity in the Galactic Center
• 3D CMZ V: A new orbital model of our Galaxy's Center, informed by data across the electromagnetic spectrum