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Rapid Continuum Variability in NGC 4151

Published online by Cambridge University Press:  12 April 2016

Rick Edelson
Rick Edelson*
Affiliation:
Department of Physics and Astronomy, 203 Van Allen Hall, University of Iowa, Iowa City, IA 52240, USA

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The bright Seyfert 1 galaxy NGC 4151 was monitored intensively by IUE, ROSAT, ASCA, CGRO, and ground-based telescopes for 10 days in 1993 December. The source, which was near its peak historical brightness, showed strong, correlated variability at X-ray, ultraviolet, and optical wavelengths (see Fig. la). The strongest variations were seen in medium energy (~1.5keV) X-rays, with a normalized variability amplitude (NVA) of 24%. Weaker (NVA = 6%) variations, uncorrelated with those at lower energies, were seen at soft γ-ray energies of ~100keV. No significant variability was seen in softer (0.1–1 keV) X-ray bands. In the ultraviolet/optical regime, the NVA decreased within increasing wavelength, from 9% to 1% between 1275 Å and 6900 Å.

Type
I. X-Rays and the Nuclear Regions of Active Galaxies
Information
International Astronomical Union Colloquium , Volume 159: Emission Lines in Active Galaxies: New Methods and Techniques , 1997 , pp. 78 - 79
Copyright
Copyright © Astronomical Society of the Pacific 1997

References

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