The nature of arms in spiral galaxies. I - Azimuthal colour profiles of NGC 7479 and NGC 1832

Beckman, J. E.; Cepa, J.
Bibliographical reference

Astronomy and Astrophysics (ISSN 0004-6361), vol. 229, no. 1, March 1990, p. 37-46.

Advertised on:
3
1990
Number of authors
2
IAC number of authors
1
Citations
26
Refereed citations
24
Description
A set of parameters to characterize azimuthal profiles of galaxies is proposed and applied to the spiral structure of the galaxies NGC 1832 and NGC 7479 observed in the B and I passbands. Interpretations of the observations in terms of the two most widely discussed theories of star formation, the spiral density wave theory and that of self-stochastic propagation of star formation, are considered. NGC 7479, with well defined arms, seems to maintain a leading density wave; evidence is presented for a phase separation in the B and I bands corresponding to star formation stimulated by the passage of the wave. NGC 1832, with more flocculent spiral arms, presents a more confused interpretational pattern.