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A detailed X-ray variability study of the Seyfert galaxy NGC 4051

Papadakis, I. E.; Lawrence, A.

We present a detailed and rigorous examination of the X-ray variability characteristics of the Seyfert galaxy NGC 4051, using the 1985 EXOSAT observation and our improved power spectrum modelling techniques. The Medium Energy (ME) power spectrum is adequately fitted by a power-law model, but the Low Energy (LE) spectrum is not. We find an excellen…

Long-term X-ray variability of NGC 4151

Papadakis, I. E.; McHardy, I. M.

We present a new method of estimating the power spectrum in the case of unevenly sampled data, together with its application to the long X-ray light curve of the Seyfert galaxy NGC 4151. This method is based on the Fourier transform of the observed autocovariance function. The method is simple to use and wisely applicable. The long-term power spec…

X-ray observations of NGC 1851 and the globular cluster LMXBs

Charles, P. A.; Callanan, P. J.; Penny, A. J.

We present new Ginga observations of the globular cluster X-ray source 4U 0513-40 in NGC 1851. Despite the 2-d time-base of the observations, no eclipsing or dipping modulation was found. The spectrum can be well modelled by a power law of index 2.1 to energies of at least 10 keV. We find from archive EXOSAT data that an additional blackbody contr…

X-ray timing and spectral behaviour of the Rapid Burster

Lewin, Walter H. G.; van Paradijs, Jan; Lubin, Lori M. +3 more

We present an X-ray fast-timing and spectral analysis of the type II bursts and the persistent emission (PE) of the Rapid Burster observed with the EXOSAT Medium-Energy Instrument. The hardness-intensity and colour-colour diagrams of the Rapid Burster are somewhat different from those of the majority of other low-mass X-ray binaries, which fall in…