The Astrophysical Journal · 1971 · 16 citations · 0 references
Natural SciencesAstronomyPhysicsAstrophysicsObservational AstronomyX-ray AstronomyExtragalactic X-ray SourcesHigh-energy Astrophysical SourcesSolar FlaresX-ray Source Detection
On 1969 April 16 we carried out balloon X-ray observations from Australia (energies above 18 keV). We detected a strong X-ray flux in the range 18-36 keV from a source at 122 = 301 + 3 , b'2 - 3 . During our observations the X-ray flux flared up by about a factor of 3. The flare lasted for a period of about hours. There is also some evidence for a flux change in less than 10 minutes. The average observed flux was about 2 keV cm sec-i, which is at least a factor of 7 higher than that observed about one month earlier on 1969 March 20, at which time no evidence for X-ray emission from this region of the sky was found by Lewin, McClintock, and Smith. The average flux is about as high as that observed by Lewin, Clark, and Smith on 1967 October 15 from a source at 1 - 304?8 + 1?5, b21 = -1?5 + 20.