Production of Millisecond Dips in Sco X-1 Count Rates by Dead Time Effects

Abstract

Chang et al. (2006) reported millisecond duration dips in the X-ray intensity of Sco X-1 and attributed them to occultations of the source by small trans-Neptunian objects (TNOs). We have found multiple lines of evidence that these dips are not astronomical in origin, but rather the result of high-energy charged particle events in the RXTE PCA detectors. Our analysis of the RXTE data indicates that at most 10% of the observed dips in Sco X-1 could be due to occultations by TNOs, and, furthermore, we find no positive or supporting evidence for any of them being due to TNOs. We therefore believe that it is a mistake to conclude that any TNOs have been detected via occultation of Sco X-1.

arXiv commentSubmitted to ApJ; uses emulateapj.cls, 8 pages with 8 figures

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• Calibration of the Rossi X-ray Timing Explorer Proportional Counter Array
• The Size Distribution of Trans-Neptunian Bodies
• Millisecond dips in the RXTE/PCA light curve of Sco X-1 and TNO occultation

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