Trigonometric Parallaxes of Massive Star-Forming Regions. IX. The Outer Arm in the First Quadrant

Дата и время публикации : 2011-10-19T15:43:35Z

Авторы публикации и институты :
A. Sanna
M. J. Reid
T. M. Dame
K. M. Menten
A. Brunthaler
L. Moscadelli
X. W. Zheng
Y. Xu

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 19 pages, 5 figures, 4 tables, accepted by The Astrophysical Journal
Первичная категория: astro-ph.GA

Все категории : astro-ph.GA

Краткий обзор статьи: We report a trigonometric parallax measurement with the Very Long Baseline Array for the water maser in the distant high-mass star-forming region G75.30+1.32. This source has a heliocentric distance of 9.25+-0.45 kpc, which places it in the Outer arm in the first Galactic quadrant. It lies 200 pc above the Galactic plane and is associated with a substantial HI enhancement at the border of a large molecular cloud. At a Galactocentric radius of 10.7 kpc, G75.30+1.32 is in a region of the Galaxy where the disk is significantly warped toward the North Galactic Pole. While the star-forming region has an instantaneous Galactic orbit that is nearly circular, it displays a significant motion of 18 km/s toward the Galactic plane. The present results, when combined with two previous maser studies in the Outer arm, yield a pitch angle of about 12 degrees for a large section of the arm extending from the first quadrant to the third.

Category: Physics