X-rays from Sources 3C 273 and M 87

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Science  13 Oct 1967:
Vol. 158, Issue 3798, pp. 257-259
DOI: 10.1126/science.158.3798.257


An x-ray survey of the Virgo region revealed signals from the directions of 3C 273 and M 87. Three other x-ray sources appear in the region scanned, but do not fit any known radio sources. The x-ray flux (1 to 10 angstroms) from the direction of 3C 273 is about 1000 times weaker than from the strongest x-ray source, Sco XR-1. If the source is located at the cosmological distance of 500 megaparsecs, the x-ray luminosity is 7.3 x 1045 ergs per second. The x-ray luminosity of M87 is 1.5 x 1043 ergs per second.