PARALLAXES FOR W49N AND G048.60+0.02: DISTANT STAR FORMING REGIONS IN THE PERSEUS SPIRAL ARM
- Max-Plank-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Department of Astronomy, Nanjing University, Nanjing 210093 (China)
- Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
We report trigonometric parallax measurements of 22 GHz H{sub 2}O masers in two massive star-forming regions from Very Long Baseline Array observations as part of the Bar and Spiral Structure Legacy Survey. The distances of 11.11{sup +0.79}{sub -0.69} kpc to W49N (G043.16+0.01) and 10.75{sup +0.61}{sub -0.55} kpc to G048.60+0.02 locate them in a distant section of the Perseus arm near the solar circle in the first Galactic quadrant. This allows us to locate accurately the inner portion of the Perseus arm for the first time. Combining the present results with sources measured in the outer portion of the arm in the second and third quadrants yields a global pitch angle of 9.°5 ± 1.°3 for the Perseus arm. We have found almost no H{sub 2}O maser sources in the Perseus arm for 50° < 80°, suggesting that this ≈6 kpc section of the arm has little massive star formation activity.
- OSTI ID:
- 22270966
- Journal Information:
- Astrophysical Journal, Vol. 775, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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