Statistics – Computation
Scientific paper
Dec 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994a%26a...292..175b&link_type=abstract
Astronomy and Astrophysics (ISSN 0004-6361), vol. 292, no. 1, p. 175-182
Statistics
Computation
32
Binary Stars, Computational Astrophysics, Cygnus Constellation, High Resolution, Power Spectra, Statistical Analysis, Stellar Physics, Temporal Resolution, X Ray Astronomy, X Ray Spectra, X Ray Stars, Computerized Simulation, Exosat Satellite, High Frequencies, Monte Carlo Method, Noise Spectra, Poisson Ratio, Stellar Luminosity, Stellar Models, Stellar Winds
Scientific paper
We have studied the fast timing behavior of Cygnus X-3 using the entire EXOSAT ME dataset on this source, consisting of 22 observations that cover a total of 320 000 seconds. This large amount of data allowed us to measure the rapid (greater than 1 Hz) X-ray variability of the source to an unprecedented accuracy of 0.2% fractional rms amplitude. Above 256 Hz, the power of the X-ray count rate fluctuations is significantly below the level predicted from Poisson statistics modified by the known dead time processes in the instrument. We developed an improved empirical method for predicting the Poisson level in EXOSAT ME High Time Resolution 3 (HTR3) and HTR5 data, and use it in our present analysis. None of the four other X-ray sources studied had a weaker noise-component in the region 1-256 Hz as the power spectra of Cygnus X-3. An instrumental effect could therefore not be excluded. If the effect is instrumental, the 99% confidence upper limit on the 1-256 Hz rapid variability of Cygnus X-3 is 0.6% rms. The consequences of these results for previously reported EXOSAT HTR observations are briefly discussed. We compare our results to the predictions of the stellar wind model for Cygnus X-3. Monte Carlo simulations were carried out to investigate the signal-attenuating effect of the wind. For the most likely wind parameters, the intrinsic source variability is found to be either very strong (approximately 60% rms), unlike seen in any other X-ray source at similar luminosity, or to be less than or approximately 12%, which would be consistent with a black hole candidate in the high state, or a low magnetic field neutron star.
Berger Martin
van der Klis Michael
No associations
LandOfFree
High time resolutions observations of Cygnus X-3 with EXOSAT 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 High time resolutions observations of Cygnus X-3 with EXOSAT, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High time resolutions observations of Cygnus X-3 with EXOSAT will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1317570