The power spectral properties of the Z source GX 340+0

被引:70
作者
Jonker, PG
van der Klis, M
Wijnands, R
Homan, J
van Paradijs, J
Méndez, M
Ford, EC
Kuulkers, E
Lamb, FK
机构
[1] Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands
[2] Univ Amsterdam, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands
[3] MIT, Ctr Space Res, Cambridge, MA 02139 USA
[4] Univ Alabama, Huntsville, AL 35899 USA
[5] Natl Univ La Plata, Fac Ciencias Astron & Geofis, RA-1900 La Plata, Argentina
[6] SRON, NL-3584 CA Utrecht, Netherlands
[7] Univ Utrecht, Astron Inst, NL-3507 TA Utrecht, Netherlands
[8] Univ Illinois, Dept Phys & Astron, Urbana, IL 61801 USA
关键词
accretion; accretion disks; stars : individual (GX 340+0); stars : neutron; X-rays : stars;
D O I
10.1086/309029
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present an analysis of similar to 390 ks of data of the Z source GX 340+0 taken during 24 observations with the Rossi X-Ray Timing Explorer satellite. We report the discovery of a new broad component in the power spectra. The frequency of this component varied between 9 and 14 Hz and remained close to half that of the horizontal-branch quasi-periodic oscillations (HBOs). Its rms amplitude was consistent with being constant around similar to 5%, while its FWHM increased with frequency from 7 to 18 Hz. If this sub-HBO component is the fundamental frequency, then the HBO and its second harmonic are the second and fourth harmonic component, while the third harmonic was not detected. This is similar to what was recently found for the black hole candidate XTE J1550-564. The profiles of both the horizontal- and the normal-branch quasi-periodic oscillation peaks were asymmetric when they were strongest. We describe this in terms of a shoulder component at the high-frequency side of the quasiperiodic oscillation peak, of which the rms amplitudes were approximately constant at similar to 4% and similar to 3%, respectively. The peak separation between the twin kilohertz quasi-periodic oscillations was consistent with being constant at 339+/-8 Hz, but a trend similar to that seen in, e.g., Sco X-l could not be excluded. We discuss our results within the framework of the various models that have been proposed for the kilohertz QPOs and low-frequency peaks.
引用
收藏
页码:374 / 386
页数:13
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