Journal
ASTRONOMY & ASTROPHYSICS
Volume 452, Issue 3, Pages 975-984Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361:20054397
Keywords
accretion, accretion disks; stars : binaries : close; stars : individual : Cyg X-1; X-rays : binaries
Categories
Ask authors/readers for more resources
Building on results from previous studies of Cygnus X-1, we analyze Rossi X-ray Timing Explorer (RXTE) data taken when the source was in the soft and transitional spectral states. We look at the power spectrum in the 0.01-50 Hz range, using a model consisting of a cut-off-power-law and two Lorentzian components. We are able to constrain the relation between the characteristic frequencies of the Lorentzian components, and show that it is consistent with a power-law relation having the same index (1.2) as previously reported for the hard state, but shifted by a factor similar to 2. Furthermore, it is shown that the change in the frequency relation seen during the transitions can be explained by invoking a shift of one Lorentzian component to a higher harmonic, and we explore the possible support for this interpretation in the other component parameters. With the improved soft state results we study the evolution of the fractional variance for each temporal component. This approach indicates that the two Lorentzian components are connected to each other, and unrelated to the power-law component in the power spectrum, pointing to at least two separate emission components.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available