Computer Models of Colliding Galaxies

MAR 01, 1993

Simulations offer insights into transformations of galaxies: Colliding spiral galaxies can merge, undergo bursts of rapid star formation and evolve to become elliptical galaxies.

DOI: 10.1063/1.881376

Joshua E. Barnes

Lars E. Hernquist

Galaxies come in a wide variety of sizes and shapes. Most have an ordered structure and can be classified as spirals or ellipticals. Spiral galaxies are flattened disks in which nearly all the stars orbit in the same direction about a common center; ellipticals are oval swarms of stars distributed in complicated three‐dimensional orbits. These are highly symmetric forms, suggesting a good degree of stability. Some galaxies, however, possess markedly irregular features. The nature of such “peculiar” galaxies and their relationship to more ordinary galaxies has long been a matter of controversy. Computer models, combined with increasingly powerful observations, offer a resolution: Many peculiar systems are ordinary galaxies in collision, and these collisions are transforming galaxies from one type to another.

This article is only available in PDF format

References

1. A. Toomre, J. Toomre, Astrophys. J. 178, 623 (1972).https://doi.org/ASJOAB
2. B. T. Soifer, J. R. Houck, G. Neugebauer, Annu. Rev. Astron. Astrophys. 25, 187 (1987).https://doi.org/ARAAAJ
3. H. Arp, Astrophys. J. Suppl. 14, 1 (1966).
4. A. Stockton, in Dynamics and Interactions of Galaxies, R. Wielsen, ed., Springer‐Verlag, New York (1990), p. 440.
5. S. D. M. White, in Internal Kinematics and Dynamics of Galaxies, E. Athanassoula, ed., Reidel, Dordrecht, The Netherlands (1983), p. 337.
6. F. Schweizer, Science 231, 227 (1986).https://doi.org/SCIEAS
7. A. Toomre, in The Evolution of Galaxies and Stellar Populations, B. Tinsley, R. Larson, ed., Yale U. Observatory, New Haven, Conn. (1977), p. 401.
8. J. Barnes, L. Hernquist, F. Schweizer, Scientific American, August 1991, p. 40.
9. J. Barnes, L. Hernquist, Annu. Rev. Astron. Astrophys. 30, 705 (1992).https://doi.org/ARAAAJ
10. J. Binney, S. Tremaine, Galactic Dynamics, Princeton U.P., Princeton, N.J. (1987).
11. L. D. Landau, E. M. Lifshitz, Fluid Mechanics, Pergamon, Oxford (1959).
12. R. W. Hockney, J. W. Eastwood, Computer Simulation Using Particles, Adam Hilger, New York (1989).
13. J. A. Sellwood, Annu. Rev. Astron. Astrophys. 25, 151 (1987).https://doi.org/ARAAAJ
14. A. W. Appel, SIAM J. Sci. Stat. Comput. 6, 85 (1985). https://doi.org/SIJCD4
J. G. Jernigan, in Dynamics of Star Clusters, J. Goodman, P. Hut, eds., Reidel, Dordrecht, The Netherlands (1985), p. 275.
J. E. Barnes, P. Hut, Nature 324, 446 (1986). https://doi.org/NATUAS
L. Greengard, V. Rokhlin, J. Comput. Physics 73, 325 (1987).
15. D. Hillis, J. E. Barnes, Nature 326, 27 (1987).https://doi.org/NATUAS
16. J. J. Monaghan, Annu. Rev. Astron. Astrophys. 30, 543 (1992).https://doi.org/ARAAAJ
17. L. Hernquist, N. Katz, Astrophys. J. Suppl. 70, 419 (1989).https://doi.org/APJSA2
18. A. Toomre, in The Structure and Evolution of Normal Galaxies, S. M. Fall, D. Lynden‐Bell, eds., Cambridge U.P., Cambridge, England (1981), p. 111.
19. D. Lynden‐Bell, Mon. Not. R. Astron. Soc. 136, 101 (1967).https://doi.org/MNRAA4
20. J. E. Barnes, Astrophys. J. 393, 484 (1992).https://doi.org/ASJOAB
21. L. Hernquist, Nature 340, 687 (1989). https://doi.org/NATUAS
J. E. Barnes, L. Hernquist, Astrophys. J. 370, L65 (1991).https://doi.org/ASJOAB
22. L. Hernquist, J. E. Barnes, Nature 354, 210 (1991).https://doi.org/NATUAS
23. D. N. C. Lin, J. E. Pringle, M. J. Rees, Astrophys. J. 328, 103 (1988).https://doi.org/ASJOAB

More about the Authors

Joshua E. Barnes. Institute for Astronomy, University of Hawaii, Honolulu.

Lars E. Hernquist. University of California, Santa Cruz.