• Corpus ID: 118908886

Density-Wave Spiral Theories in the 1960s. II

  title={Density-Wave Spiral Theories in the 1960s. II},
  author={I. I. Pasha},
  journal={arXiv: Astrophysics},
  • I. Pasha
  • Published 6 June 2004
  • Physics
  • arXiv: Astrophysics
By the 1970s the spiral subject was in considerable disarray. The semiempirical theory by Lin and Shu was confronted with serious problems. They were put on the defensive over their tightly wrapped steady modes on two principal fronts: from the radial propagation at the group velocity that would tend to wind them almost at the material rate, and from the tendencies of galaxy disks toward a strong global instability that appeared likely to overwhelm them. Of course, one might claim that such… 
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