The distribution of kHz QPO frequencies in Sco X-1

Tomaso Belloni; Mariano Mendez; Jeroen Homan

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The distribution of kHz QPO frequencies in Sco X-1

Tomaso Belloni·Mariano Mendez·Jeroen Homan

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Abstract

The frequencies of kHz Quasi-Periodic Oscillations in the bright Low-Mass X-ray Binary Sco X-1 have been reported to appear preferentially in a 3:2 ratio. We show that a proper statistical analysis of those RXTE data upon which the claim is based indicated a 2.4 sigma deviation from a constant distribution in ratios. The analysis of a much larger RXTE/PCA dataset shows that there is no sharp concentration around a 3:2 ratio, but that the ratios are broadly distributed over the range 820-1150 Hz.

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Tomaso Belloni, Mariano Mendez, Jeroen Homan. 2004-09-17. The distribution of kHz QPO frequencies in Sco X-1. https://arxiv.org/abs/astro-ph/0409432

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