The Intergalactic Medium: Initial and Boundary Conditions for Galaxy and Primeval Star Formation

  • Mark L. Giroux
  • Paul R. Shapiro
Conference paper
Part of the Astrophysics and Space Science Library book series (ASSL, volume 162)


The formation of the first stars in gas of primordial composition depended upon the complex interplay of the hydrodynamics of gravitational collapse with nonequilibrium chemistry and its effect on the thermal evolution of the gas. The initial conditions and boundary values for the clouds which collapsed gravitationally to form galaxies and stars were determined by the thermal and ionization history of the general intergalactic medium. We describe new detailed numerical calculations of the evolution of the intergalactic medium in a post-recombination Friedmann universe, including a solution of the nonequilibrium rate equations for the ionization and recombination of H and He, the energy equation, and the equation of radiative transfer. The implications of this study for the characteristic mass scale and epoch of gravitational collapse for the average “first” star forming clouds will be discussed. The star formation rate and associated metallicity generation implied if the intergalactic medium was fully ionized by starlight by redshift z > 4 as suggested by recent interpretations of the Gunn-Peterson effect will also be discussed. Finally, we show that the relative strengths of metal lines from a quasar absorption-line Lyman limit system cloud at z = 3 photoionized by our intergalactic uv radiation background are compatible with the observations, at least for background sources of either AGN-type or star-forming galaxy spectra.


Star Formation Cosmic Microwave Background Gravitational Collapse Cold Dark Matter Source Spectrum 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Shapiro, P. R. 1989, in Fourteenth Texas Symposium on Relativistic Astrophysics, ed. E. J. Fenyves, Ann. N. Y. Acad. Sci., 571, pp. 128–150.Google Scholar
  2. 2.
    Peebles, P J E. and Dicke, R.H. 1968, Ap. J., 154, 891.ADSCrossRefGoogle Scholar
  3. 3.
    Blumenthal, G. R., Faber, S. M., Primack, J. R., Rees, M. J., 1984, Nature, 311, 517.ADSCrossRefGoogle Scholar
  4. 4.
    White, S. D. M., Frenk, C. S., Davis, M., and Efstathiou, G., 1987, Ap. J., 313, 505.ADSCrossRefGoogle Scholar
  5. 5.
    Jones, B. J. T. and Wyse, R. F. G. 1985, Astron. and Astrophys., 149, 144.ADSGoogle Scholar
  6. 6.
    Peebles, P. J. E. 1984, Ap. J., 277, 470.ADSCrossRefGoogle Scholar
  7. 7.
    Shapiro, P. R. 1986, in Galaxy Distances and Deviations from Universal Expansion, eds. B. F. Madore and R.B. Tully (Dordrecht: Reidel), pp. 203–213.Google Scholar
  8. 8.
    Shapiro, P. R. 1986, P. A. S. P., 98, 1014.ADSCrossRefGoogle Scholar
  9. 9.
    Shapiro P.R., and Giroux M. L., 1987, Ap. J. (Letters), 321, L107.ADSCrossRefGoogle Scholar
  10. 10.
    Shapiro, P. R., Giroux, M. L., and Kang, H. 1987, in High Redshift and Primeval Galaxies, eds. J. Bergeron, D. Kunth, B. Rocca-Volmer ange, J. Tran Thanh Van (Paris: Editions Frontières), pp.501— 515.Google Scholar
  11. 11.
    Shapiro, P. R. and Giroux, M. L. 1989, in The Epoch of Galaxy Formation, eds. C. S. Frenk, R. S. Ellis, T. Shanks, A. F. Heavens, and J. A. Peacock (Boston: Kluwer Academic Publishers), pp. 153–161.Google Scholar
  12. 12.
    Donahue, M. and Shull, J. M. 1987, Ap. J., 323, L13.ADSCrossRefGoogle Scholar
  13. 13.
    Bond, J. R., Szalay, A. S., and Silk, J. 1988, Ap. J., 324, 627.ADSCrossRefGoogle Scholar
  14. 14.
    Miralda-Escude, J. and Ostriker, J. P. 1990, preprint.Google Scholar
  15. 15.
    Ikeuchi, S. and Ostriker, J. P. 1986, Ap. J., 301, 522.ADSCrossRefGoogle Scholar
  16. 16.
    Schneider, D. P., Schmidt, M., Gunn, J. E. 1989, Astron. J., 98, 1951.ADSCrossRefGoogle Scholar
  17. 17.
    Batjlik, S., Duncan, R. C., and Ostriker, J. P. 1988, Ap. J., 327, 570.ADSCrossRefGoogle Scholar
  18. 18.
    Bruzual, G. 1983, Ap. J. Suppl., 53, 497.ADSCrossRefGoogle Scholar
  19. 19.
    Steidel, C. C. and Sargent, W.L.W. 1989, Ap. J. (Letters), 343, L33.ADSCrossRefGoogle Scholar
  20. 20.
    Ferland, G. J. 1989, Ohio State University Astronomy Department Internal Report, 90–001.Google Scholar

Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Mark L. Giroux
    • 1
  • Paul R. Shapiro
    • 1
  1. 1.Department of AstronomyThe University of Texas at AustinAustinUSA

Personalised recommendations