Advertisement

Quasars and Other Active Nuclei

  • Françoise Combes
  • Patrick Boissé
  • Alain Mazure
  • Alain Blanchard
Chapter
Part of the Astronomy and Astrophysics Library book series (AAL)

Abstract

Radio astronomy was responsible for the discovery of the first quasars. As long ago as 1960 several radio sources in the 3C catalogue had been noticed on account of their remarkably small angular size and were therefore particularly suitable for a search for an associated optical object. For 3C 48, optical exposures of the corresponding field indicated an object with a stellar appearance; its spectrum showed very strong emission lines that at first could not be identified. In 1962 Hazard, Mackey, and Shimmins, using the telescope at Parkes, succeeded in locating the source 3C 273 with great precision (better than 1″), thanks to a lunar occultation. Analysis of the light-curve profile at the beginning and end of the occultation showed, moreover, the existence of two components, A and B, separated by 20″; the second, 3C 273B, coincides exactly with a stellarlike object (m V ≈ 13) whose spectrum also turned out to have very strong emission lines. Schmidt discovered that these were in fact hydrogen lines that have been redshifted by an amount z = Δλ/λ0 = 0.158. Hence it was realized that if 3C 273 obeys the Hubble law, it is at an extremely large distance and has an enormous intrinsic luminosity (of the order of 1047 ergs s−1).

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Baldwin, J. E. (1977) in Active Galactic Nuclei, edited by C. Hazard and S. Mitton ( Cambridge University Press, Cambridge ), p. 51.Google Scholar
  2. Blandford, R. D., Netzer, H., and Woltjer, L. (1990) Active Galactic Nuclei (Saas-Fee Advanced Course 20, Springer, Berlin, Heidelberg ).Google Scholar
  3. Collin, S. (1987) in L’Activité dans les Galaxies, edited by G. Stasinska ( Les Editions de Physique, Les Ullis ), p. 3.Google Scholar
  4. Green, R. F. (1985) in Quasars, edited by G. Swarup and V. K. Kapahi ( Reidel, Dordrecht ), p. 429.Google Scholar
  5. Greenfield, P. E., Roberts, D. H., and Burke, B. F. (1985) Astrophys. J. 293, 370.ADSCrossRefGoogle Scholar
  6. Hazard, C., and Mitton, S. (1979) Active Galactic Nuclei ( Cambridge University Press, Cambridge).Google Scholar
  7. Hoag, A. A., and Smith, M. G. (1977) Astrophys. J. 217, 362.ADSCrossRefGoogle Scholar
  8. Hutchings, J. B., Crampton, D., Campbell, B., Duncan, D., and Glendenning, B. (1984) Astrophys. J. Suppl. 55, 319.ADSCrossRefGoogle Scholar
  9. Malkan, M. A. (1983) Astrophys. J. 268, 582.ADSCrossRefGoogle Scholar
  10. Osterbrock, D. E. and Miller, J. S. (editors) (1989) Active Galactic Nuclei ( IAU Symposium 134, Kluwer, Dordrecht ).Google Scholar
  11. Soucail, G., Mellier, Y., Fort, B., Mathez, G., and Cailloux, M. (1988) Astron. Astrophys. 191, L19.ADSGoogle Scholar
  12. Stockton, A. (1980) Astrophys. J. 242, L141.ADSCrossRefGoogle Scholar
  13. Sullentic, J. W., and Lorre, J. J. (1983) Astron. Astrophys. 120, 36.ADSGoogle Scholar
  14. Swamp, G, and Kapahi, V. K. (editors) (1986) Quasars ( IAU Symposium 119, Reidel, Dordrecht ).Google Scholar
  15. Ulrich, M. H. et al. (1984) Mon. Not. Roy. Ast. Soc. 206, 221.ADSGoogle Scholar
  16. Vanderriest, C. et al. (1989) Astron. Astrophys. 215, 1.ADSGoogle Scholar
  17. Warren, S. J., Hewett, P. C., Osmer, P. S., and Irwin, M. J. (1987) Nature 330, 453.ADSCrossRefGoogle Scholar
  18. Weedman, D. (1986) Quasar Astronomy ( Cambridge University Press, Cambridge).CrossRefGoogle Scholar
  19. Worall, D. M., Boldt, E. A., Holt, S. S, and Serlemitsos, P. J. (1980) Astrophys. J. 240, 421.ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • Françoise Combes
    • 1
  • Patrick Boissé
    • 2
  • Alain Mazure
    • 3
  • Alain Blanchard
    • 4
  1. 1.Observatoire de ParisDEMIRMParisFrance
  2. 2.Ecole Normale SupérieureParis Cedex 5France
  3. 3.GRAAL, Université de Montpellier IIMontpellier Cedex 5France
  4. 4.Observatoire de StrasbourgStrasbourgFrance

Personalised recommendations