The Norma spiral arm: large-scale pitch angle

Abstract

In the inner Galaxy, we statistically find the mean pitch angle of the recently mapped Norma arm in two galactic quadrants (observed tangentially at galactic longitudes near l=328 degrees and near l=20 degrees), using the twin-tangent method, and obtain -13.7 +/-1.4 degrees. We compared with other measurements in the literature. Also, using the latest published data on pitch angle and the latest published data on the radial starting point of the four arms (RGal = 2.2 kpc) in each galactic quadrant, a revised velocity plot of the Norma spiral arm is made, along with other spiral arms in the Milky Way, in each Galactic quadrant.

12 pages, 4 figures, 2 tables; accepted for publication in Astrophysics and Space Science

References in corpus (3)

• The observed spiral structure of the Milky Way
• Recent advances in the determination of some Galactic constants in the Milky Way
• The prevalence of star formation as a function of Galactocentric radius

Cited by in corpus (5)

• A guided map to the Spiral arms in the galactic disk of the Milky Way
• Constraining the pitch angle of the Galactic spiral arms in the Milky Way
• A New Multi-Tracer Approach to Defining the Spiral arm width in the Milky Way
• Interarm islands in the Milky Way -- the one near the Cygnus spiral arm
• Arm Tangents and the spiral structure of the Milky Way ; the Age Gradient