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arXiv · 1306.0168

Discovery of twin kHz quasi periodic oscillations in the low mass X-ray binary XTE J1701-407

Devraj D. Pawar·Maithili Kalamkar·Diego Altamirano·Manuel Linares·K. Shanthi·Tod Strohmayer·Dipankar Bhattacharya·Michiel van der Klis
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Abstract

We report the discovery of kHz quasi periodic oscillations (QPOs) in three Rossi X-ray Timing Explorer observations of the low mass X-ray binary (LMXB) XTE J1701-407. In one of the observations we detect a kHz QPO with a characteristic frequency of 1153 +/- 5 Hz, while in the other two observations we detect twin QPOs at characteristic frequencies of 740 +/- 5 Hz, 1112 +/- 17 Hz and 740 +/- 11 Hz, 1098 +/- 5 Hz. All detections happen when XTE J1701-407 was in its high intensity soft state, and their single trial significance are in the 3.1-7.5 sigma range. The frequency difference in the centroid frequencies of the twin kHz QPOs (385 +/- 13 Hz) is one of the largest seen till date. The 3-30 keV fractional rms amplitude of the upper kHz QPO varies between ~18 % and ~30 %. XTE J1701-407, with a persistent luminosity close to 1 % of the Eddington limit, is among the small group of low luminosity kHz QPO sources and has the highest rms for the upper kHz QPO detected in any source. The X-ray spectral and variability characteristics of this source indicate its atoll source nature.

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Devraj D. Pawar, Maithili Kalamkar, Diego Altamirano, Manuel Linares, K. Shanthi, Tod Strohmayer, Dipankar Bhattacharya, Michiel van der Klis. 2013-06-02. Discovery of twin kHz quasi periodic oscillations in the low mass X-ray binary XTE J1701-407. https://doi.org/10.1093/mnras%2Fstt919

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