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Density distribution and the radial velocity field in the spiral arms of M31

Published online by Cambridge University Press:  14 August 2015

J. Einasto  and
U. Rümmel
J. Einasto
Affiliation:
W. Struve Astrophysical Observatory, Tartu, Estonian S.S.R.
U. Rümmel
Affiliation:
W. Struve Astrophysical Observatory, Tartu, Estonian S.S.R.

Abstract

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The density distribution and the radial velocity field in the Andromeda galaxy, M 31, have been studied on the basis of the 21-cm radio-line data from Jodrell Bank and Green Bank. The true density has been obtained from the observed one by solving a two-dimensional integral equation. As the resolving power of the radio telescopes is too low to locate all spiral arms separately, optical data on the distribution of ionized hydrogen clouds have been also used. The mean radial velocities have been derived by solving a two-dimensional non-linear integral equation with the help of hydrogen densities, and a model radial velocity field.

The inner concentrations of hydrogen form two patchy ringlike structures with mean radii 30′ and 50′, the outer concentrations can be represented as fragments of two leading spiral arms.

The rotational velocity, derived from the radial velocity field, in the central region differs considerably from the velocity curves obtained by earlier authors. The difference can be explained by the fact that in this region the correction for the antenna beam width is much greater than adopted by previous investigators.

Type
Part I/Spiral Structure in Galaxies
Information
Symposium - International Astronomical Union , Volume 38: The Spiral Structure of our Galaxy , 1970 , pp. 42 - 50
Copyright
Copyright © Reidel 1970 

References

Argyle, E.: 1965, Astrophys. J. 141, 750.Google Scholar
Arp, H.: 1964, Astrophys. J. 139, 1045.Google Scholar
Baade, W.: 1963, Evolution of Stars and Galaxies, Harvard University Press, Cambridge.Google Scholar
Baade, W. and Arp, H.: 1964, Astrophys. J. 139, 1027.Google Scholar
Davies, R. D.: 1969, personal communication.Google Scholar
Deharveng, J. M. and Pellet, A.: 1969, Astron. Astrophys. 1, 208.Google Scholar
Einasto, J. and Rümmel, U.: 1969, Astrofiz., in press.Google Scholar
Gottesman, S. T., Davies, R. D., and Reddish, V. C.: 1966, Monthly Notices Roy. Astron. Soc. 133, 359.Google Scholar
Roberts, M. S.: 1966, Astrophys. J. 144, 639.CrossRefGoogle Scholar
Roberts, M. S.: 1967, IAU Symposium No. 31, p. 189.Google Scholar
Roberts, M. S.: 1969, personal communication.Google Scholar
Schmidt, M.: 1957, Bull. Astron. Inst. Netherl. 13, 247.Google Scholar
Van den Bergh, S.: 1964, Astrophys. J. Suppl. Ser. 9, 65.Google Scholar
Westerhout, G. 1957, Bull. Astron. Inst. Netherl. 13, 201.Google Scholar