3D Astrophysics Newsletter

2017_8_1_yan8.1 Today´s new entry:

Towards a three-dimensional distribution of the molecular clouds in the Galactic Centre

Qing-Zeng Yan, A. J. Walsh, J. R. Dawson, J. P. Macquart, R. Blackwell, M. G. Burton, G. Rowell, Bo Zhang, Ye Xu, Zheng-Hong Tang, P. J. Hancock

Abstract: We present a study of the three-dimensional structure of the molecular clouds in the Galactic Centre (GC) using CO emission and OH absorption lines. Two CO isotopologue lines, 12CO (J=1-0) and 13CO (J=1-0), and four OH ground-state transitions, surveyed by the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH), contribute to this study. We develop a novel method to calculate the OH column density, excitation temperature, and optical depth precisely using all four OH lines, and we employ it to derive a three-dimensional model for the distribution of molecular clouds in the GC for six slices in Galactic latitude. The angular resolution of the data is 15.5 arcmin, which at the distance of the GC (8.34 kpc) is equivalent to 38 pc. We find that the total mass of OH in the GC is in the range 2400-5100 Solar mass. The face-on view at a Galactic latitude of b=0° displays a bar-like structure with an inclination angle of 67.5±2.1° with respect to the line of sight. No ring-like structure in the GC is evident in our data, likely due to the low spatial resolution of the CO and OH maps.

Journal: Monthly Notices of the Royal Astronomical Society (MNRAS), accepted
Comments:
 Accepted (07 July 2017), 15 pages, 12 figures
URL of preprint: https://arxiv.org/pdf/1707.02378.pdf
Submitted by: Qing-Zeng Yan

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