Simultaneous X-ray/optical observations of GX 339-4 during the May 1981 optically bright state.
Abstract
Ariel 6 observations of GX 339-4 during the May 1981 optically bright state reveal the presence in X-rays of the 20-s quasi-periodic oscillation found in the optical range as well as a strong 10-s harmonic quasi-oscillation. The observed X-ray spectrum is the hardest reported for this bimodal source up to now. A 96-s simultaneous observation on May 28 reveals that variations on time scales longer than about 15 s are anticorrelated with the optical leading the X-rays by 2.8 + or -1.6 s. Shorter time scale variations do not appear to be correlated with the exception of X-ray flares which occur simultaneously with optical dips. The 13-20 keV range is found to have a statistically different behavior, suggesting that part of the high energy X-rays is positively correlated with the optical. Most of the behavior of GX 339-4 can be understood within the framework of the models developed for Cyg X-1 describing the inner accretion flow onto a black hole.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1983
- Bibcode:
- 1983A&A...119..171M
- Keywords:
-
- Binary Stars;
- Stellar Flares;
- Stellar Spectrophotometry;
- Visual Photometry;
- X Ray Sources;
- Ariel Satellites;
- Astronomical Spectroscopy;
- Black Holes (Astronomy);
- Cross Correlation;
- Data Processing;
- Periodic Variations;
- Power Spectra;
- Radiant Flux Density;
- Temporal Distribution;
- X Ray Spectra;
- Astronomy