ASCA observations of Seyfert 1 galaxies: I. Data Analysis, Imaging and Timing

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dc.creatorNandra, K.
dc.creatorGeorge, I. M.
dc.creatorMushotzky, R. F.
dc.creatorTurner, T. J.
dc.creatorYaqoob, T.
dc.date1996-08-26
dc.date.accessioned2026-07-07T11:08:22Z
dc.date.available2026-07-07T11:08:22Z
dc.descriptionWe present the first in a series of papers describing the X-ray properties of a sample of 18 Seyfert 1 galaxies, using data obtained by \asca. The imaging data reveal a number of serendipitous hard X-ray sources in some source fields, but none contribute significantly to the hard X-ray flux of the AGN. All but one of the Seyferts show evidence for variability on timescales of minutes-hours, with the amplitude anti-correlated with the source luminosity, confirming previous results. In at least 8 sources, there is evidence that the variability amplitude below 2 keV is greater than that in the hard X-ray band, perhaps indicating variable components other than the power-law in the soft band. Ultra-rapid variability, implying significant power at frequencies $> 10^{-3}$~Hz is detected in at least 5 sources, but is difficult to detect in most cases, due to the sampling and signal-to-noise ratio. In Mrk 766 and MCG-6-30-15 there is also an indication that the high--frequency power--spectra are variable in shape and/or intensity. There is similar evidence in NGC 4151, but on longer time scales.
dc.description30 pages, 5 figures. LaTeX with encapsulated postscript. To appear in the Astrophysical Journal. Also available via http://lheawww.gsfc.nasa.gov/~nandra/pubs/paper1/abstract.html
dc.identifierhttps://arxiv.org/abs/astro-ph/9608170
dc.identifierhttp://arxiv.org/abs/astro-ph/9608170
dc.identifierAstrophys.J.Suppl.113:23,1997
dc.identifierdoi:10.1086/313053
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/190113
dc.subjectAstrophysics
dc.titleASCA observations of Seyfert 1 galaxies: I. Data Analysis, Imaging and Timing
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