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Long Timescale Variability of NGC 4151статья
- Авторы: Czerny B., Niko\lajuk M., Doroshenko V., Loska Z.
- Сборник: X-ray Emission from Accretion onto Black Holes
- Серия: Proceedings of a joint workshop held by the Center for Astrophysics (Johns Hopkins University) and the Laboratory for High Energy Astrophysics (NASA/ Goddard Space Flight Center) in Baltimore, MD, June 20-23, 2001,
- Год издания: 2001
- Место издания: http://adsabs.harvard.edu/abs/2001xeab.confE..13C , Eds.: T. Yaqoob and J. H. Krolik, to be published electronically
- Аннотация: The presence or absence of the radiation pressure instability in accretion disks is currently under discussion. Resolving it from the theoretical side is quite complex so an alternative approach, from the observational side, is useful. In this work we study the long term variability of NGC 4151 on the basis of 90 years of optical data and 25 years of X-ray data. We calculate the power spectra and the structure functions in both energy bands. The results clearly show that two separate instability mechanisms are at work: short timescale variations are predominantly connected with X-ray emission and are most probably caused by some hot plasma instabilities while long timescale trends dominate in the optical band and therefore are directly connected with optically thick disk instabilities. Flattening of the power spectra and the structure function at about 1-3 days in X-ray band and 10 years in B band indicate the characteristic timescales of the corresponding processes.
- Добавил в систему: Дорошенко Валентина Трофимовна