The theory of spiral density waves had its origin approximately six decades ago in an attempt to reconcile the winding dilemma of material spiral arms in flattened disk galaxies. We begin with the earliest calculations of linear and nonlinear spiral density waves in disk galaxies, in which the hypothesis of quasi-stationary spiral structure (QSSS) plays a central role. The earliest success was the prediction of the nonlinear compression of the interstellar medium and its embedded magnetic field; the earliest failure, seemingly, was not detecting color gradients associated with the migration of OB stars whose formation is triggered downstream from the spiral shock front. We give the reasons for this apparent failure with an update on the current status of the problem of OB star formation, including its relationship to the feathering substructure of galactic spiral arms. Infrared images can show two-armed, grand design spirals, even when the optical and UV images show flocculent structures. We suggest how the nonlinear response of the interstellar gas, coupled with overlapping subharmonic resonances, might introduce chaotic behavior in the dynamics of the interstellar medium and Population I objects, even though the underlying forces to which they are subject are regular. We then move to a discussion of resonantly forced spiral density waves in a planetary ring and their relationship to the ideas of disk truncation, and the shepherding of narrow rings by satellites orbiting nearby. The back reaction of the rings on the satellites led to the prediction of planet migration in protoplanetary disks, which has had widespread application in the exploding data sets concerning hot Jupiters and extrasolar planetary systems. We then return to the issue of global normal modes in the stellar disk of spiral galaxies and its relationship to the QSSS hypothesis, where the central theoretical concepts involve waves with negative and positive surface densities of energy and angular momentum in the regions interior and exterior, respectively, to the corotation circle; the consequent transmission and overreflection of propagating spiral density waves incident on the corotation circle; and the role of feedback from the central regions.


Article metrics loading...

Loading full text...

Full text loading...


Literature Cited

  1. Abramowitz M, Stegun IA. 1965. Handbook of Mathematical Functions New York: Dover
  2. Adams FC, Ruden SP, Shu FH. 1989. Ap. J. 347:959
  3. Allen RJ, Atherton PD, Tilanus RPJ. 1986. Nature 319:296
  4. Artymowicz P, Lubow S. 1992. Ap. J. 389:129
  5. Balbus SA, Cowie LL. 1985. Ap. J. 297:61
  6. Beck R. 2015. Ap. Space Sci. Libr. 407:507
  7. Bender CM, Orszag SA. 1999. Advanced Mathematical Methods for Scientists and Engineers New York: Springer
  8. Bertin G, Lau YY, Lin CC. et al. 1977. PNAS 74:4726
  9. Bertin G, Lin CC. 1996. Spiral Structure in Galaxies: A Density Wave Theory Cambridge, MA: MIT Press
  10. Blitz L, Spergel DN. 1991a. Ap. J. 370:205
  11. Blitz L, Spergel DN. 1991b. Ap. J. 379:631
  12. Block DL, Bertin G, Stockton A. et al. 1994. Astron. Astrophys. 288:365
  13. Block DL, Elmegreen BG, Wainscoat RJ. 1996. Nature 381:674
  14. Block DL, Wainscoat RJ. 1991. Nature 353:48
  15. Borderies N, Goldreich P, Tremaine S. 1983. Astron. J. 88:226
  16. Borderies N, Goldreich P, Tremaine S. 1985. Icarus 63:406

Data & Media loading...

  • Article Type: Review Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error