X-Ray and Optical Observations of Quasars
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).
Unable to display preview. Download preview PDF.
- Cavaliere, A., Danese, L., DeZotti, G., and Franceschini, A. 1980 preprint.Google Scholar
- Green, R.F. and Schmidt, M. 1981, private communication.Google Scholar
- Kron, R.G. 1980, in Two Dimensional Photometry (ESO Workshop) P.O. Lindblad and H. van der Laan, eds., Geneva, p.349.Google Scholar
- Kron, R.G. and Chiu, L.T.G. 1981, preprint.Google Scholar
- Kron, R.G. 1981, private communication.Google Scholar
- Marshall, H.L., et al. 1981, in preparation.Google Scholar
- Veron, P. and Veron M.P. 1981, Astron. Astrophys., submitted.Google Scholar
- Zamorani, G. 1981, private communication.Google Scholar