1998/04/22 by W. Zhang, Tod E. Strohmayer, T. E. Strohmayer +1 · 2 citations
Engineering · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Magnetic confinement fusion research #Particle Accelerators and Free-Electron Lasers #astro-ph
paper · pdf · doi:10.1086/311423
5 pages, LaTex (aas2pp4), Accepted for publication in ApJ Lett
arxiv created 1998/04/22 · openalex publication_date 1998/06/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We report the discovery of two simultaneous quasi-periodic oscillations in the persistent flux of GX 349+2 at frequencies 712±9 and 978±9 Hz, with rms amplitudes 1.25%±0.34% and 1.34%±0.32%, respectively. During our 152 ks observation with the Rossi X-ray Timing Explorer , GX 342+2 was in either the normal branch or the flaring branch with count rates in the nominal 2-60 keV RXTE -PCA band ranging from a low of 8000 counts s -1 to a high of 15,000 counts s -1 . The kHz QPOs were observed only when the source was at the top of the normal branch, when the count rate was about 8200 counts s -1 , corresponding to a flux of 1.4 × 10 −8 ergs cm -1 s -1 in the 2-10 keV band. With this report, now kHz QPOs have been observed in all six Z sources.