Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-29T16:26:08.660Z Has data issue: false hasContentIssue false

Gas at Large Radii

Published online by Cambridge University Press:  04 August 2017

R. Sancisi*
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, Groningen, the Netherlands

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

A considerable fraction of the neutral hydrogen in spiral galaxies is generally found at large radii and beyond the optical image. This outlying gas either forms an extension of the stellar disk and of the inner HI layer, or, is concentrated in a ring. It shows well ordered motion around the galaxy, although the plane of the orbits is generally inclined with respect to the inner disk. The study of this gas is important for at least three reasons: i) although it represents only a very small fraction of the total mass it can be used as a tracer of the kinematics to determine the total mass and the mass distribution of the system, ii) it contributes to the galactic cross-sections needed to explain QSO absorption lines, iii) its physical and chemical properties may throw some light on the formation of galactic disks and their evolution.

Type
I. Kinematics of Gas and the Underlying Mass Distribution
Copyright
Copyright © Reidel 1983 

References

Athanassoula, E.: 1979, Ann. Phys. 4, 115.Google Scholar
Bahcall, J.N.: 1982, preprint.Google Scholar
Baldwin, J.E. Lynden-Bell, D. and Sancisi, R.: 1980, Mon. Not. R. Astr. Soc. 193, 313.Google Scholar
Blitz, L., Fich, M., and Kulkarni, S.: 1982, preprint.Google Scholar
Bosma, A.: 1981a, Astron. J. 86, 1791.Google Scholar
Bosma, A.: 1981b, Astron. J. 86, 1825.Google Scholar
Bosma, A., Hulst, J.M. van der, Sullivan, W.T. III: 1977, Astron. Astrophys. 57, 37.Google Scholar
Briggs, F.H.: 1982, preprint.Google Scholar
Briggs, F.H., Wolfe, A.M., Krumm, N., and Salpeter, E.E.: 1980, Astrophys. J. 238, 510.Google Scholar
Casertano, S.: 1982, Mon. Not. R. Astr. Soc., in press.Google Scholar
Fall, S.M., and Efstathiou, G.: 1980, Mon. Not. R. Astr. Soc. 193, 189.Google Scholar
Giovanardi, C., Helou, G., Salpeter, E.E., and Krumm, N.: 1982, preprint.Google Scholar
Heckman, T.M., Sancisi, R., Sullivan, W.T. III, and Balick, B.: 1982, Mon. Not. R. Astr. Soc. 199, 425.Google Scholar
Henderson, A.P., Jackson, P.D., and Kerr, F.J.: 1982, preprint.Google Scholar
Kruit, P.C. van der: 1979, Astron. Astrophys. Suppl. 38, 15.Google Scholar
Kruit, P.C. van der, and Searle, L.: 1981, Astron. Astrophys. 95, 105.Google Scholar
Kruit, P.C. van der, and Searle, L.: 1982, Astron. Astrophys. 110, 61.Google Scholar
Rogstad, D.H., Lockhart, I.A., Wright, M.C.H.: 1974, Astrophys. J. 193, 309.CrossRefGoogle Scholar
Sancisi, R.: 1981, in “The Structure and Evolution of Normal Galaxies”, pp. 149, Ed. Fall, S.M. and Lynden-Bell, D., Cambridge Univ. Press.Google Scholar
Sancisi, R., and Allen, R.J.: 1979, Astron. Astrophys. 74, 73.Google Scholar
Sofue, Y., and Kato, T.: 1981, Publ. Astron. Soc. Japan 33, 449.Google Scholar