Can GX 340+0 be One More Neutron Star Source With Spectral Index - QPO Frequency Correlation?
Abstract
We present timing and spectral analysis of Rossi X-Ray Timing Explorer (RXTE) archival data from GX 340+0. A correlation between spectral power-law index and frequencies of QPO oscillations has been recently found among several black hole candidates and neutron stars. In both black hole and neutron star systems an increase of frequencies of QPOs is accompanied by an increase in the photon index. In the black holes, the photon index saturates at Γ 2.0 for Cyg X-1 and at Γ 2.8 for GRS 1915+105 and XTE J1550+564 while QPO frequencies continue to increase. In contrast, this saturation effect has not been observed in neutron stars, with 4U 1728-34 and Cyg X-2 being the most notable examples. Thus, this saturation effect could be a distinctive feature of black hole systems. In this work we study the correlation between spectral index and QPO frequency for another neutron star binary, GX 340+0, which also shows no saturation of the spectral index.
- Publication:
-
American Astronomical Society Meeting Abstracts #210
- Pub Date:
- May 2007
- Bibcode:
- 2007AAS...210.2006K