The rms-flux relation of Cyg X-2 in the horizontal branch

被引：3
作者：
Li ZhiBing [1 ]
Lei YaJuan [1 ]
Qu JinLu [1 ]
Zhang Shu [1 ]
Song LiMing [1 ]
机构：
[1] Chinese Acad Sci, Inst High Energy Phys, Key Lab Particle Astrophys, Beijing 100049, Peoples R China
来源：
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY | 2010年 / 53卷
基金：
中国国家自然科学基金;
关键词：
accretion; accretion disk; binaries: close; stars: individual (Cygnus X-2); X-rays: binaries; X-RAY BINARIES; TIME-LAG; ACTIVE GALAXIES; NEUTRON-STAR; VARIABILITY; ACCRETION; EVOLUTION; RXTE; LONG; MASS;
D O I：
10.1007/s11433-010-0007-3
中图分类号：
O4 [物理学];
学科分类号：
0702 ;
摘要：
We have investigated the relation between the root mean square (rms) variability and the X-ray flux (rms-flux relation) of the Z source Cyg X-2, and as well the energy dependence based on the Rossi X-ray Timing Explorer (RXTE) observations. We currently focus on the horizontal branch (HB), due to the negative correlation in flux of the soft and the hard X-rays. The rms-flux correlation has energy dependence as follows: positive at hard X-rays (above 10 keV) but negative at soft X-rays (below 10 keV). This provides a feature different from the previous one, and may be suggestive of different origins of X-rays below and above 10 keV. Nevertheless, the overall spectrum can be well fitted with a model consisting of a blackbody and Comptonization components, but the fitting results do not reveal any features around 10 keV that could account for such a change in the rms-flux relation.
引用
收藏
页码：86 / 90
页数：5
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