The Lin–Shu type density wave structure of our Galaxy: line-of-sight velocities of 396 HII regions
In this fifth paper in a series, we check again the Lin–Shu idea of small-amplitude density waves in our Galaxy. The updated catalogue of Galactic objects of Hou and Han (Hou and Han in Astron Astrophys 569:125–146, 2014), available in the literature, is used. The line-of-sight velocity field of 396 HII regions with known trigonometric or photometric distances and their uncertainties within 4 kpc from the Sun is investigated in terms of a wave perturbation. Our previous study is enlarged by examining the secondary minima of the residual sum of squares of the predicted and measured velocities of a sample of objects in a considerable region surrounding the Sun. Both the geometrical and physical parameters of the wave pattern are evaluated. Here we show, for the first time, that the local Cygnus–Orion spiral arm, where the Sun is located, does form a part of the major density wave structure of the system under the question but is not a spur originating at the inner Carina–Sagittarius arm or at the outer Perseus arm.
KeywordsGalaxy Galaxy kinematics Spiral structure Cygnus-Orion spiral arm
The authors have benefited from numerous discussions with David Eichler, Alex Kaganovich, Edward Liverts and Yury Luybarsky. It is a special pleasure to thank Michael Gedalin for his informative comments and important suggestions that have improved this work. Irena Zlatopolsky provided valuable technical assistance. We also wishes to thank the anonymous referee for helping improve the manuscript. A late part of this work was done while one of us (EG) was visiting the National Tsing-Hua University, thanks to an NSC month long visitor grant. EG is grateful to Ing-Guey Jiang and Wen-Ping Chen for the hospitality they and their colleagues extended to EG in Hsin-Chu and Jhong-Li. We gratefully acknowledge support from the Israel Science Foundation, the Binational U.S.-Israel Science Foundation, the Israeli Ministry of Immigrant Absorption in the framework of the program “KAMEA,” the National Natural Science Foundation of China and the National Science Council in Taiwan.
- Efremov, Yu.N.: On the spiral structure of the Milky Way Galaxy. Astron. Rep. 55, 108–122 (2011)Google Scholar
- Foster, T.J., Brunt, C.M.: A CGPS look at the spiral structure of the outer Milky Way. I. Distances and velocities to star forming regions, arXiv:1405.7003F (2014)
- García-Lorenzo, B., Márquez, I., Barrera-Ballesteros, J.K., Masegosa, J., et al.: Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems. Astron. Astrophys. 573, 59–102 (2015)ADSCrossRefGoogle Scholar
- Kharadze, E.K., Bartaya, R.A., Dluzhnevskaya, O.B., Piskunov, A.E., Pavlovskaya, E.D.: Population of the galactic disc in the solar neighbourhood. I. Parameters of spatial distribution for stellar groups of A-K spectral and III–V luminosity classes. Astrophys. Space Sci. 151, 319–334 (1989)ADSCrossRefGoogle Scholar
- Lin, C.C., Yuan, C., Shu, F.H.: On the spiral structure of disk galaxies. III. Comparison with observations, Astrophys. J. 155, 721–746 (erratum, 156, 797) (1969)Google Scholar
- Mihalas, D., Binney, J.: Galactic Astronomy, 2nd edn. Freeman, San Francisco (1998)Google Scholar
- Mishurov, Yu.N., Pavlovskaya, E.D., Suchkov, A.A.: Galactic spiral structure parameters derived from stellar kinematics. Sov. Astron. 23, 147–152 (1979)Google Scholar
- Mishurov, Yu.N., Zenina, I.A.: Parameters of the Galactic rotation curve and spiral pattern from Cepheid kinematics. Astron. Rep. 43, 487–493 (1999)Google Scholar
- Mishurov, Yu.N., Zenina, I.A., Dambis, A.K., Melnik, A.M., Rastorguev, A.S.: Is the Sun located near the corotation circle? Astron. Astrophys. 323, 775–780 (1997)Google Scholar
- Morozov, A.G., Torgashin, Yu.M., Fridman, A.M.: Turbulent viscosity in a gravitating gaseous disk. Sov. Astron. Lett. 11, 94–97 (1985)Google Scholar
- Reid, M.J.: Galactic structure from trigonometric parallaxes of star-forming regions, in Advancing the Physics of Cosmic Distances, IAU Symp. 289, ed. R. de Grijs (IAU), 188-193 (2013)Google Scholar
- Rohlfs, K.: Lectures on Density Wave Theory. Lecture Notes in Physics 69. Springer, Berlin (1977)Google Scholar