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The CO Rotation Curve of the Milky Way : Accuracy and Implications

Published online by Cambridge University Press:  04 August 2017

Leo Blitz
Leo Blitz*
Affiliation:
University of Maryland

Extract

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The CO rotation curve exhibits an increase in circular velocity beyond R = 12 kpc (Blitz, Fich, and Stark 1980) which may be as much as 50 km s−1 at R = 18 kpc. Recently, Blitz and Fich (1983) have examined the uncertainties in the rotation curve at large R and have concluded that : 1) Of all the uncertainties, small changes in Ro and θo have the most serious effect on the rise at large R. However, unless ωo < 20 km s−1 kpc−1, a value smaller than that accepted by all observers, the rotation curve rises beyond R = 12 kpc. 2) Systematic errors in stellar distances and non-circular motions might have an effect on the magnitude of the rise. Both effects are thought to be small, but probably work to make the rotation curve even steeper. 3) The global value of the Oort A constant is < 12.5 km s−1 kpc−1, and the local value of 15 km s−1 kpc−1 is most likely due to a local velocity perturbation.

Type
I. Kinematics of Gas and the Underlying Mass Distribution
Information
Symposium - International Astronomical Union , Volume 100: Internal Kinematics and Dynamics of Galaxies , 1983 , pp. 43 - 44
Copyright
Copyright © Reidel 1983 

References

Blitz, L., Fich, M., and Stark, A.A., 1980, in Interstellar Molecules, Andrew, B. H., ed. Reidel : Dordrecht, p; 213.Google Scholar
Blitz, L., and Fich, M., 1983, in Structure, Dynamics and Kinematics of the Milky Way, Shuter, W. L. H., ed., D. Reidel: Dordrecht, p. 143.Google Scholar
Kellman, S. A., 1972, Ap. J. 175, 363.Google Scholar
Kulkarni, S. R., Blitz, L., and Heiles, C., 1982, Ap. J. (Letters), 259, L63.CrossRefGoogle Scholar
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