Hostname: page-component-76fb5796d-zzh7m Total loading time: 0 Render date: 2024-04-25T18:11:37.875Z Has data issue: false hasContentIssue false
  • English
  • Français

AGN Variability

Published online by Cambridge University Press:  25 May 2016

Toshihiro Kawaguchi  and
Shin Mineshige
Toshihiro Kawaguchi
Affiliation:
Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
Shin Mineshige
Affiliation:
Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan

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.

A number of monitoring observations of continuum emission from Active Galactic Nuclei (AGNs) have been made in optical-X-ray bands. The results obtained so far show (i) random up and down on timescales longer than decades, (ii) no typical timescales of variability on shorter timescales and (iii) decreasing amplitudes as timescales become shorter. The second feature indicates that any successful model must produce a wide variety of shot-amplitudes and -durations over a few orders in their light curves. In this sense, we conclude that the disk instability model is favored over the starburst model, since fluctuations on days are hard to produce by the latter model.

Inter-band correlations and time lags also impose great constraints on models. Thus, constructing wavelength and time dependent models remains as future work.

Type
IV. AGN Related Phenomena
Information
Symposium - International Astronomical Union , Volume 194: Activity in Galaxies and Related Phenomena , 1999 , pp. 356 - 363
Copyright
Copyright © Astronomical Society of the Pacific 1999 

References

Aretxaga, I., Cid Fernandes, R., & Terlevich, R. J. 1997, MNRAS, 286, 271 CrossRefGoogle Scholar
Bak, P., Tang, C., & Wiesenfeld, K. 1988, Phys.Rev.A, 38, 364 CrossRefGoogle Scholar
Cid Fernandes, R. et al. 1996, MNRAS, 283, 419 CrossRefGoogle Scholar
Clavel, J. C. et al. 1991, ApJ, 366, 64 Google Scholar
Courvoisier, T. J.-L. 1998, these proceedings Google Scholar
Cristiani, S. et al. 1996, A&A, 306, 395 Google Scholar
Di Clemente, A. et al. 1996, ApJ, 463, 466 Google Scholar
Edelson, R. A. et al. 1996, ApJ, 470, 364 CrossRefGoogle Scholar
Fahlman, G. G., & Ulrych, T. J. 1975, ApJ, 201, 277 Google Scholar
Hayashida, K. et al. 1998, ApJ, 500, 642 Google Scholar
Hook, I. M. et al. MNRAS, 268, 305 CrossRefGoogle Scholar
Kawaguchi, T., Mineshige, S., Umemura, M., & Turner, E. L. 1998, ApJ, 504, 671 CrossRefGoogle Scholar
Korista, K. T. et al. 1995, ApJS, 97, 285 CrossRefGoogle Scholar
Kundić, T. et al. 1997, ApJ, 482, 75 CrossRefGoogle Scholar
Leighly, K. M., & O'Brien, P. T. 1997, ApJ, 481, L15 Google Scholar
Maoz, D. et al. 1993, ApJ, 404, 576 CrossRefGoogle Scholar
Matsumoto, R., & Shibata, K. 1998, in preparation Google Scholar
Mineshige, S., Takeuchi, M., & Nishimori, H. 1994, ApJ, 435, L125 Google Scholar
Nandra, K. et al. 1998, ApJ, 505, 594 CrossRefGoogle Scholar
Paltani, S., & Courvoisier, T. J.-L. 1997, A&A, 323, 717 Google Scholar
Peterson, B. M. et al. 1994, ApJ, 425, 622 CrossRefGoogle Scholar
Peterson, B. M. et al. 1998, PASP, 110, 660 CrossRefGoogle Scholar
Takeuchi, M., Mineshige, S., & Negoro, H. 1995, PASJ, 47, 617 Google Scholar
Terlevich, R. et al. MNRAS, 255, 713 Google Scholar
Trèvese, D. 1998, these proceedings Google Scholar
Ulrich, M.-H., Maraschi, L., & Urry, C. M. 1997, ARA&A, 35, 445 Google Scholar