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

作者：Pawar Devraj D^*; Kalamkar Maithili; Altamirano Diego; Linares Manuel; Shanthi K; Strohmayer Tod; Bhattacharya Dipankar; van der Klis Michiel

来源：Monthly Notices of the Royal Astronomical Society, 2013, 433(3): 2436-2444.

DOI：10.1093/mnras/stt919

• binaries: general
• stars: individual: XTE J1701-407
• stars: neutron
• X-rays: binaries

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 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, 1112 +/- 17 Hz and 740 +/- 11, 1098 +/- 5 Hz. All detections happen when XTE J1701-407 was in its high-intensity soft state, and their single-trial significance is 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 similar to 18 and similar to 30 per cent. XTE J1701-407, with a persistent luminosity close to 1 per cent 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.

• 出版日期2013-8