Asymmetric peak of the quasi-periodic oscillations in the power spectra of X 1820-30 observed with Ginga.
Abstract
Quasi-periodic oscillations (QPOs) in the X-ray flux from X1820-30 in the globular cluster NGC 6624 were observed with the Ginga satellite when the source was in its high state. The QPO peak profile in the power spectra was very broad and asymmetric in frequency and was therefore fitted with two Lorentzians. The centroid frequency of the lower Lorentzian was about 7 Hz and almost constant, even when the source intensity varied by 30 percent. On the other hand, that of the higher Lorentzian varied from 15 to 30 Hz, showing an anticorrelation with the X-ray intensity in some of the data.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- 1989
- Bibcode:
- 1989PASJ...41..577D
- Keywords:
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- Ginga Satellite;
- Globular Clusters;
- Power Spectra;
- Satellite Observation;
- Stellar Mass;
- X Ray Binaries;
- Japanese Space Program;
- Stellar Oscillations;
- X Ray Sources;
- Astrophysics