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 \(l=328^{\circ}\) and near \(l=20^{\circ}\)), using the twin-tangent method, and obtain \(-13.7^{\circ}\pm 1.4^{\circ}\). 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 (\(R_{\mathrm{Gal}} = 2.2~\mbox{kpc}\)) 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.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4

References

  1. Drimmel, R.: Astron. Astrophys. 358, L13 (2000)

    ADS  Google Scholar 

  2. García, P., Bronfman, L., Nyman, L.-A., Dame, T.M., Luna, A.: Astrophys. J. Suppl. Ser. 212, 2 (2014), 33 pp

    ADS  Article  Google Scholar 

  3. Green, J.A., et al.: Mon. Not. R. Astron. Soc. 469, 1383 (2017)

    ADS  Article  Google Scholar 

  4. Hou, L.G., Han, J.L.: Astron. Astrophys. 569, 125 (2014), 23 pp

    ADS  Article  Google Scholar 

  5. Hou, L.G., Han, J.L.: Mon. Not. R. Astron. Soc. 454, 626 (2015)

    ADS  Article  Google Scholar 

  6. Hou, L.G., Han, J.L., Shi, W.B.: Astron. Astrophys. 499, 473–482 (2009)

    ADS  Article  Google Scholar 

  7. Nakanishi, H., Sofue, Y.: Publ. Astron. Soc. Jpn. 68(1), 5 (2016), 14 pp

    ADS  Article  Google Scholar 

  8. Ragan, S.E., Moore, T.J., Eden, D.J., Hoare, M.G., Elia, D., Molinari, S.: Mon. Not. R. Astron. Soc. 462, 3123 (2016)

    ADS  Article  Google Scholar 

  9. Reid, M.J., Dame, T.M., Menten, K.M., Brunthaler, A.: Astrophys. J. 823, 77 (2016)

    ADS  Article  Google Scholar 

  10. Steiman-Cameron, T.Y., Wolfire, M., Hollenbach, D.: Astrophys. J. 722, 1460–1473 (2010)

    ADS  Article  Google Scholar 

  11. Vallée, J.P.: Astron. J. 135, 1301 (2008)

    ADS  Article  Google Scholar 

  12. Vallée, J.P.: Mon. Not. R. Astron. Soc. 450, 4277 (2015)

    ADS  Article  Google Scholar 

  13. Vallée, J.P.: Astron. J. 151, 55 (2016a)

    ADS  Article  Google Scholar 

  14. Vallée, J.P.: Astrophys. J. 821, 53 (2016b)

    ADS  Article  Google Scholar 

  15. Vallée, J.P.: Astrophys. Space Sci. 362, 79 (2017a)

    ADS  Article  Google Scholar 

  16. Vallée, J.P.: Astrophys. Space Sci. 362, 84 (2017b)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

The figure production made use of the PGPLOT software at NRC Canada in Victoria. I thank an anonymous referee for useful, careful, and historical suggestions.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Jacques P. Vallée.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Vallée, J.P. The Norma spiral arm: large-scale pitch angle. Astrophys Space Sci 362, 173 (2017). https://doi.org/10.1007/s10509-017-3145-5

Download citation

Keywords

  • Galaxies: spiral
  • Galaxy: disk
  • Galaxy: structure
  • Methods: statistical
  • ISM: general
  • ISM: structure