X-Ray and Optical Observations of Quasars

  • Harvey Tananbaum
  • Herman L. Marshall
Part of the International Astronomical Union / Union Astronomique Internationale book series (IAUS, volume 97)

Abstract

The first Einstein observations established that quasars, as a class, are luminous X-ray emitters (Tananbaum et al. 1979). Since then, one of our major programs has been to carry out further X-ray and optical observations to improve our estimate of the contribution of quasars to the 2 keV extragalactic isotropic X-ray background and also to reconcile number counts of discrete X-ray sources with reported optical number counts of quasars (cf. Zamorani et al. 1981 and references therein). This paper is a preliminary report on our observations of the 1.7 square degree field studied originally by Braccesi and his colleagues (Formiggini et al. 1980 and Braccesi et al. 1980). A more detailed presentation of our results is in preparation (Marshall et al., 1981).

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Avni, Y., Soltan, A,, Tananbaum, H,, and Zamorani, G, 1980, Ap.J., 238, 800.ADSCrossRefGoogle Scholar
  2. Bonoli, F., Braccesi, A., Marano, B., Merighi, R., and Zitelli, V. 1980, Astron. Astrophys., 90, L10.ADSGoogle Scholar
  3. Braccesi, A., Formiggini, L., and Gandolfi, E. 1970, Astron. Astrophys., 5, 264.ADSGoogle Scholar
  4. Braccesi, A., Zitelli, V., Bonoli, F., and Formiggini, L. 1980, Astron. Astrophys., 85, 80.ADSGoogle Scholar
  5. Cavaliere, A., Danese, L., DeZotti, G., and Franceschini, A. 1980 preprint.Google Scholar
  6. Formiggini, L., Zitelli, V., Bonoli, F., and Braccesi, A. 1980, Astron. Astrophys. Suppl., 39, 129.ADSGoogle Scholar
  7. Green, R.F. and Schmidt, M. 1978, Ap.J.(Lett.), 220, L1.ADSCrossRefGoogle Scholar
  8. Green, R.F. and Schmidt, M. 1981, private communication.Google Scholar
  9. Kron, R.G. 1980, in Two Dimensional Photometry (ESO Workshop) P.O. Lindblad and H. van der Laan, eds., Geneva, p.349.Google Scholar
  10. Kron, R.G. and Chiu, L.T.G. 1981, preprint.Google Scholar
  11. Kron, R.G. 1981, private communication.Google Scholar
  12. Marshall, H.L., et al. 1981, in preparation.Google Scholar
  13. Setti, G. and Woltjer, L. 1979, Astr. and Astrophys., 76, L1.ADSGoogle Scholar
  14. Tananbaum, H., Avni, Y., Branduardi, G., Elvis, M., Fabbiano, G., Feigelson, E., Giacconi, R., Henry, J.P., Pye, J.P., Soltan, A., and Zamorani, G. 1979, Ap.J.(Lett.), 234, L9.ADSCrossRefGoogle Scholar
  15. Veron, P. and Veron M.P. 1981, Astron. Astrophys., submitted.Google Scholar
  16. Zamorani, G., Henry, J.P., Maccacaro, T., Tananbaum, H., Soltan, A., Avni, Y., Liebert, J., Stocke, J., Strittmatter, P.A., Weymann, R.J., Smith, M.G., and Condon, J.J. 1981, Ap.J., 245, 357.ADSCrossRefGoogle Scholar
  17. Zamorani, G. 1981, private communication.Google Scholar

Copyright information

© IAU 1982

Authors and Affiliations

  • Harvey Tananbaum
    • 1
  • Herman L. Marshall
    • 1
  1. 1.Harvard-Smithsonian Center for AstrophysicsUSA

Personalised recommendations