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Long-term studies with the Ariel 5 ASM. I - Hercules X-1, Vela X-1, and Centaurus X-3Twelve hundred days of 3-6 keV X-ray data from Her X-1, Vela X-1, and Cen X-3 accumulated with the Ariel 5 All-Sky Monitor are interrogated. The binary periodicities of all three can be clearly observed, as can the 35 day variation of Her X-1, for which we can refine the period to 34.875 plus or minus 0.030 days. No such longer-term periodicity less than 200 days is observed from Vela X-1. The 26.6 days low-state recurrence period for Cen X-3 is not observed, but a 43.0 day candidate periodicity is found which may be consistent with the precession of an accretion disk in that system. The present results are illustrative of the long-term studies which can be performed on approximately 50 sources over a temporal base which will ultimately extend to at least 1800 days.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Holt, S. S. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kaluzienski, L. J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Boldt, E. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Serlemitsos, P. A. (NASA Goddard Space Flight Center Laboratory for High Energy Astrophysics, Greenbelt, Md., United States)
Date Acquired
August 9, 2013
Publication Date
January 15, 1979
Publication Information
Publication: Astrophysical Journal
Subject Category
Distribution Limits