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Discovery of a Periodic Pulsating Binary X-Ray Source in Hercules from UHURU
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1972
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X-ray SpectroscopyEngineeringAstrostatisticsX-ray ImagingX-ray TechnologyRadiation ImagingHealth SciencesGeodesyPhotometryPhysicsX-ray SourceConstellation HerculesSynchrotron RadiationSpace WeatherHigh-energy AstrophysicsAstrophysicsAstroinformaticsX-ray DiffractionBinary SystemX-ray Optic
A new pulsating X‑ray source with a 1.24‑s period was discovered in Hercules. The 1.24‑s pulsations are attributed to a binary system where the companion periodically occults the X‑ray source, producing intensity dips and Doppler‑shifted period variations. The system has an orbital period of 1.70017 days, with bright, pulsing intervals lasting ~9 days followed by ~27 days of non‑detection, and the 1.24‑s pulsation period shows sinusoidal Doppler shifts. Published in The Astrophysical Journal, June 1972, DOI 10.1086/180968.
view Abstract Citations (475) References (5) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Discovery of a Periodic Pulsating Binary X-Ray Source in Hercules from UHURU Tananbaum, H. ; Gursky, H. ; Kellogg, E. M. ; Levinson, R. ; Schreier, E. ; Giacconi, R. Abstract We have discovered a new pulsating X-ray source with a 1.24 period in the constellation Hercules. Analysis of 5 months of data has shown the existence of periodic variations in the intensity of the source and correlated sinusoidal variations in the period of the 1.24 pulsations. As in the case of the pulsating X-ray source Cen X-3, we interpret this effect as due to an occulting binary system, with the intensity changes due to occultation of the X-ray source by its companion and with the sinusoidal variations in the period of the 1.24 pulsations due to the Doppler effect. The orbital period for the X-ray source is 1d.700l7 * 0d.00004, and the time of occurrence of the center of occultation is UT (1972 January 13.0772 * 0.0003) * n(1.70017 * 0.00004). In addition, we have observed a longer-timescale cycle in which the source is bright and pulsing for approximately 9 days during which we can observe the ld.7 occulting, followed by approzimately 27 days during which the source is not detected above background on individual 20-s scans. Publication: The Astrophysical Journal Pub Date: June 1972 DOI: 10.1086/180968 Bibcode: 1972ApJ...174L.143T full text sources ADS | data products SIMBAD (2)