A 100-parsec elliptical and twisted ring of cold and dense molecular clouds revealed by Herschel around the Galactic Center

S. Molinari; J. Bally; A. Noriega-Crespo; M. Compiègne; J. P. Bernard; D. Paradis; P. Martin; L. Testi; M. Barlow; T. Moore; R. Plume; B. Swinyard; A. Zavagno; L. Calzoletti; A. M. Di Giorgio; D. Elia; F. Faustini; P. Natoli; M. Pestalozzi; S. Pezzuto; F. Piacentini; G. Polenta; D. Polychroni; E. Schisano; A. Traficante; M. Veneziani; C. Battersby; M. Burton; S. Carey; Y. Fukui; J. Z. Li; S. D. Lord; L. Morgan; F. Motte; F. Schuller; G. S. Stringfellow; J. C. Tan; M. A. Thompson; D. Ward-Thompson; G. White; G. Umana

doi:10.1088/2041-8205/735/2/l33

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arXiv · 1105.5486

A 100-parsec elliptical and twisted ring of cold and dense molecular clouds revealed by Herschel around the Galactic Center

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Abstract

Thermal images of cold dust in the Central Molecular Zone of the Milky Way, obtained with the far-infrared cameras on-board the Herschel satellite, reveal a 3x10^7 solar masses ring of dense and cold clouds orbiting the Galactic Center. Using a simple toy-model, an elliptical shape having semi-major axes of 100 and 60 parsecs is deduced. The major axis of this 100-pc ring is inclined by about 40 degrees with respect to the plane-of-the-sky and is oriented perpendicular to the major axes of the Galactic Bar. The 100-pc ring appears to trace the system of stable x_2 orbits predicted for the barred Galactic potential. Sgr A* is displaced with respect to the geometrical center of symmetry of the ring. The ring is twisted and its morphology suggests a flattening-ratio of 2 for the Galactic potential, which is in good agreement with the bulge flattening ratio derived from the 2MASS data.

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S. Molinari, J. Bally, A. Noriega-Crespo, M. Compiègne, J. P. Bernard, D. Paradis, P. Martin, L. Testi, M. Barlow, T. Moore, R. Plume, B. Swinyard, A. Zavagno, L. Calzoletti, A. M. Di Giorgio, D. Elia, F. Faustini, P. Natoli, M. Pestalozzi, S. Pezzuto, F. Piacentini, G. Polenta, D. Polychroni, E. Schisano, A. Traficante, M. Veneziani, C. Battersby, M. Burton, S. Carey, Y. Fukui, J. Z. Li, S. D. Lord, L. Morgan, F. Motte, F. Schuller, G. S. Stringfellow, J. C. Tan, M. A. Thompson, D. Ward-Thompson, G. White, G. Umana. 2011-05-27. A 100-parsec elliptical and twisted ring of cold and dense molecular clouds revealed by Herschel around the Galactic Center. https://doi.org/10.1088/2041-8205/735/2/l33

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