Abstract
WE report here the discovery of an X-ray emitting QSO, the first to be initially identified from X-ray observations. Previously, the only QSO known to be an X-ray source was 3C273 (refs 1 and 2). The new QSO has been found within a 40′′ error circle established by the SAS-3 X-ray Observatory. The SAS-3 error circle lies within the Ariel V error box (∼0.2 square degrees) for the source 2A 2251-179 (ref. 3). Following the convention for optical QSOs, we have designated the optical object MR2251 — 178. The X-ray luminosity (2–11 keV) of this object, presently ∼5×1044 erg s−1, has been as large as ∼1.6×l045 erg s−1 (in 1975) and exceeds the optical luminosity by a factor of ∼ 10. Among known compact X-ray sources, only 3C273 has a greater luminosity. Also, in radio observations at 4,885 MHz with the NRAO Very Large Array (VLA), we have discovered a point-like radio source coincident with MR2251—178.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bowyer, S., Lampton, M., Mack, J. & de Mendonca, F. Astrophys. J. Lett. 161, L1–L8 (1970).
Kellogg, E. et al. Astrophys. J. Lett. 165, L49–L54 (1971).
Cooke, B. A. et al. Mon. Not. R. astr. Soc. (in the press).
Doxsey, R. E. et al. Nature 269, 112–116 (1977).
Schnopper, H. W. et al. Astrophys. J. Lett. 215, L7–L11 (1977).
MacAlpine, G. M., Smith, S. B. & Lewis, D. W. Astrophys. J. (Suppl.) 34, 95–100 (1977).
Smith, M. G. Astrophys. J. 202, 591–595 (1975).
Elvis, M. et al. Mon. Not. R. astr. Soc. (in the press).
Tananbaum, H. et al. Astrophys. J. Lett. (in the press).
Culhane, J. L. Q. J. R. Astr. Soc. (in the press).
Charles, P. A., Longair, M. S. & Sanford, P. W. Mon. Not. R. astr. Soc. 170, 17p–22p (1975).
Burbidge, G. R., Crown, A. H. & Smith, H. E. Astrophys. J. Suppl. 33, 113–188 (1977).
Huchra, J. & Sargent, W. L. W. Astrophys. J. 186, 433–444 (1973).
Schwartz, D. & Gursky, H. in X-Ray Astronomy (eds R. Giacconi & H. Gursky) 359–388 (Reidel, Dordrecht, 1974).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
RICKER, G., CLARKE, G., DOXSEY, R. et al. Discovery of an X-ray QSO. Nature 271, 35–37 (1978). https://doi.org/10.1038/271035a0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/271035a0
- Springer Nature Limited