Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-14T23:08:57.239Z Has data issue: false hasContentIssue false
  • English
  • Français

Spectral Index Versus Frequency and Models for the Continua of AGN and QSOs

Published online by Cambridge University Press:  07 August 2017

Wayne A. Stein
Wayne A. Stein*
Affiliation:
University of Minnesota, School of Physics and Astronomy, 116 Church Street S.E., Minneapolis, Minnesota 55455

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The observed spectral index as a function of frequency of QSO continua must be explained in models. It is generally increasing (F(ν) ∝ ν−α, α increasing) with higher frequency in the infrared (downward curvature). The visual to ultraviolet continuum has been shown to be a broken power law with F(ν) ∝ ν−0.5 at low frequency and a break to larger α at νo ∼ 3×1015 Hz. X-ray observations frequently exhibit a flat continuum with α < 1. One prominent example is 3C273 for which α1–3μm → 2, αvis ∼ 0.5 and αx ∼ 0.5. These spectral indices arise naturally in Secondary Electron Synchrotron Self-Compton (SESSC) models. Some accretion disk models approach these spectral indices for the visual-ultraviolet portion of the spectral distribution.

Type
Part 3: X-rays and the Central Source
Information
Symposium - International Astronomical Union , Volume 134: Active Galactic Nuclei , 1989 , pp. 201 - 202
Copyright
Copyright © Kluwer 1989 

References

Bechtold, J. et al. 1984, Ap.J., 281, 76.Google Scholar
Green, R.F. et al. 1980, Ap.J., 239, 483.Google Scholar
Jones, T.W. and Stein, W.A. 1987, Ap.J. (Letters), 320, L1.Google Scholar
Madau, P. 1988, Ap.J., 327, 116.CrossRefGoogle Scholar
Malkan, M.A. and Sargeant, W.L.W. 1982, Ap.J., 254, 22.Google Scholar
Mushotzky, R.F. et al. 1980, Ap.J., 235, 377.Google Scholar
Neugebauer, G. et al. 1979, Ap.J., 230, 79.Google Scholar
O'Dell, S.L. et al. 1987, Ap.J., 313, 164.CrossRefGoogle Scholar
Perry, J.L. et al. 1987, M.N.R.A.S., 228, 623.Google Scholar
Robson, E.I. et al. 1983, Nature, 305, 194.Google Scholar
Shields, G. 1978, Nature, 272, 706.Google Scholar
Stein, W.A. 1987, Georgia State AGN Proceedings.Google Scholar
Wandel, A. and Petrosian, V. 1988, Ap.J. (Letters), 329, L11.Google Scholar
Worrall, D.M. and Marshall, F.E. 1984, Ap.J., 276, 434.CrossRefGoogle Scholar
Zamorani, G. et al. 1981, Ap.J., 245, 357.Google Scholar