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1999MNRAS.309..991S - Mon. Not. R. Astron. Soc., 309, 991-1006 (1999/November-2)
High-resolution X-ray imaging observations of two low-luminosity Seyfert galaxies.
SINGH K.P.
Abstract (from CDS):
The nuclear component of NGC 4051 shows strong soft X-ray variability, with X-ray intensity changing by a factor of 2-3 on a time-scale of a few 100s. The power spectrum of the variability has been extended to higher frequencies compared with previous observations, and has now reached the true Poissonian noise level of the source. At lower frequencies the power spectrum is best characterized by a power law and a Gaussian. The power-law slope of ≃-1.8 is consistent with the previous low-energy observations with EXOSAT, and the presence of a Gaussian feature signifies the persistence of a quasi-periodic oscillation that was also seen earlier with EXOSAT. During its low intensity and low variability state, however, the extended component of soft X-ray emission dominates the flux in NGC 4051.
A list of X-ray sources, some of which are new, detected in the field of view of the HRI during the observations is also presented.
Abstract Copyright: 1999, Royal Astronomical Society
Journal keyword(s): galaxies: active - galaxies: individual: NGC 1365 - galaxies: individual: NGC 4051 - galaxies: nuclei - galaxies: Seyfert - X-rays: galaxies
Nomenclature: Table 3: [S99c] NN (Nos 1-16).
Simbad objects: 26
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