The emission positions of kHz QPOs and Kerr spacetime influence

Authors :: Yan Yan
H. X. Yin
Ya-Juan Lei
Fan Zhang
Li-Ming Song
Cheng-Min Zhang
Yong-Heng Zhao
Yingchun Wei
Source :: Science China Physics, Mechanics and Astronomy. 53:114-116
Publication Year :: 2010
Publisher :: Springer Science and Business Media LLC, 2010.
Abstract: Based the Alfven wave oscillation model (AWOM) and relativistic precession model (RPM) for twin kHz QPOs, we estimate the emission positions of most detected kHz QPOs to be at r=18+-3 km (R/15km) except Cir X-1 at r = 30\+-5 km (R/15km). For the proposed Keplerian frequency as an upper limit to kHz QPO, the spin effects in Kerr Spacetime are discussed, which have about a 5% (2%) modification for that of the Schwarzchild case for the spin frequency of 1000 (400) Hz.The application to the four typical QPO sources, Cir X-1, Sco X-1, SAX J1808.4-3658 and XTE 1807-294, is mentioned.<br />Comment: Science China, Physics, Mechanics & Astronomy, 2010, 53, NO.1