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arXiv · 0909.3773

Trigonometric Parallaxes of Massive Star-Forming Regions: VII. G9.62+0.20 and the Expanding 3 KPC-ARM

A. Sanna·M. J. Reid·L. Moscadelli·T. M. Dame·K. M. Menten·A. Brunthaler·X. W. Zheng·Y. Xu
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Abstract

We report a trigonometric parallax of 12 GHz methanol masers associated with the massive star forming region G9.62+0.20, corresponding to a distance of 5.2+-0.6 kpc. With a local standard of rest velocity of about 2 km/s, the region's kinematic distances of 0.5 and 16 kpc differ greatly from the distance derived here. Our measurement of the peculiar motion of the star forming region shows a very large deviation from a circular Galactic orbit: 41 km/s radially outward from the Galactic center and 60 km/s counter to Galactic rotation. The combination of its radial velocity and distance places G9.62+0.20 in the inner region of the Galaxy close to the Expanding Near 3 kpc-Arm, where the bulge/bar potential has strong gravitational influence. We also map the distribution of 12 GHz methanol masers, locate them with respect to a hypercompact H II region, and compare our data with the periodic flare phenomenon reported previously for this source.

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A. Sanna, M. J. Reid, L. Moscadelli, T. M. Dame, K. M. Menten, A. Brunthaler, X. W. Zheng, Y. Xu. 2009-09-21. Trigonometric Parallaxes of Massive Star-Forming Regions: VII. G9.62+0.20 and the Expanding 3 KPC-ARM. https://doi.org/10.1088/0004-637x/706/1/464

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