Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-11-16
Astronomy and Astrophysics
Astrophysics
9 pages, 4 figures. Accepted Astron and Astrophysics
Scientific paper
We have measured the phase-delay and rms amplitude spectra of CygX-2 and ScoX-1. Using EXOSAT data from the normal branch of CygX-2 we confirm earlier (Ginga) results, showing that at an energy near 6keV there is both a minimum in the QPO rms amplitude spectrum and a 150 degree phase jump in the quasi-periodic oscillations (QPO) phase-delay spectrum. Surprisingly, using EXOSAT and Ginga data, we find no evidence for a phase jump of this kind in the phase-delay spectrum of ScoX-1 on either the normal or flaring branch. Upper limits (90% confidence) of 42 degrees can be set on any phase jump in the energy range 2-10keV on the normal branch, and 88 degrees on the flaring branch. The QPO rms amplitude spectrum of ScoX-1 increases steeply with energy on both the normal and flaring branches. These results suggest that the X-ray spectrum pivots about an energy of <~2keV or >~10keV or that normal branch QPO of ScoX-1 does not have a pivoting spectrum. We discuss the implications of these results in terms of the radiation-hydrodynamic model for normal branch QPO.
Dieters Stefan W.
Kuulkers Erik
Lamb Frederick K.
van der Klis Michiel
Vaughan Brian A.
No associations
LandOfFree
No QPO time lags from Sco X-1 as seen with EXOSAT: a comparison with Cyg X-2 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with No QPO time lags from Sco X-1 as seen with EXOSAT: a comparison with Cyg X-2, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and No QPO time lags from Sco X-1 as seen with EXOSAT: a comparison with Cyg X-2 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-304156