Computer Science
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992sesd.reptr....d&link_type=abstract
In its Goddard Visiting Scientist Program for the Space and Earth Sciences Directorate 1 p (SEE N93-18709 06-42)
Computer Science
Active Galactic Nuclei, Light Curve, Periodic Variations, Phase Coherence, Power Spectra, Variability, X Ray Sources, Exosat Satellite, Folding, Ginga Satellite, Sampling, Stability
Scientific paper
The power spectra of the X-ray variable AGN are typically scale invariant with no characteristic timescale. The one strong exception to this is NGC6814, where the EXOSAT data showed evidence for a periodic component at 12200 plus or minus 100 seconds. The power spectra of a GINGA lightcurve from this source, found using simulation techniques to account for the uneven sampling, also cannot be well fit by a single power law. A folded light curve analysis of the GINGA data shows a strong peak in the variance, indicative of a periodic component, at 12130.9 plus or minus 0.6 seconds. A second GINGA observation of this source taken one year later is consistent with the periodicity maintaining phase coherence for 7 periods in the range of 12110-12145 seconds. Including the limits from the folding selects a period of 12130.39 plus or minus 0.05 seconds. Phase coherence is not maintained between this and the EXOSAT observations, as the structure of the folded light curves is very different. Thus the periodicity is long lived and stable, but phase coherence is only maintained on timescales of approximately 1 year.
Done Christine
Koyama Katsuji
Kunieda Hideyo
Madejski Greg M.
Mushotzky Richard F.
No associations
LandOfFree
The X ray variability of AGN and the anomalous behavior of NGC6814 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 The X ray variability of AGN and the anomalous behavior of NGC6814, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The X ray variability of AGN and the anomalous behavior of NGC6814 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1142731