The 1999 Her X-1 Anomalous Low State

Coburn, W.; Gruber, D. E.; Heindl, W. A.; Pelling, M. R.; Rothschild, R. E.; Staubert, R.; Kreykenbohm, I.; Risse, P.; Wilms, J.
April 2000
AIP Conference Proceedings;2000, Vol. 510 Issue 1, p158
Academic Journal
Recently an Anomalous Low State in the 35d cycle of Her X-1, which is thought to be caused by the tilted accretion disk, was observed with the RXTE. This has been seen only twice before; in 1983 and again 1993. We present timing and spectral results of this latest anomalous low obtained 1999 April 26. Pulsations were observed in the 2–20 keV band but with a pulsed fraction down by a factor of 10 from the main-on. Spectral analysis indicates 70% absorbed flux (N[sub H]=7×10[sup 23]) with the remainder unabsorbed. This is consistent with continuous screening of the X-ray source by the accretion disk causing the anomalous low. © 2000 American Institute of Physics.


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