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ON THE LONG TIME SPECTRAL VARIABILITY OF NGC 5548

  • ISMAILOV, NARIMAN Z. (Shamakhy Astrophysical Observatory of Azerbaijan National Academy of Sciences) ;
  • BASHIROVA, ULVIYYE Z. (Shamakhy Astrophysical Observatory of Azerbaijan National Academy of Sciences)
  • 투고 : 2014.11.30
  • 심사 : 2015.06.30
  • 발행 : 2015.09.30

초록

We have investigated the long term variability of the intensities of the broad-line region emission lines in the UV spectra of Seyfert I galaxy NGC 5548 from 1973-1996. We have obtained the following results: 1) a high level correlation between the intensities of emission lines as well as between intensities of emission lines and continuum fluxes was discovered. With increasing wavelength the correlation in both cases becomes weaker, 2) the relationship between the intensity of emission lines and the flux radiation in the continuum can be expressed by a power law function with coefficients of ${\alpha}{\approx}0.8-1.1$ for different lines. When the difference between the wavelengths of spectral lines and the continuum is increased, the value of the power function decreases, and 3) it was found that the magnitude of the variability of the line intensities are weaker than the range of variability of the continuum fluxes. The magnitude of the variability of the line intensities and the continuum fluxes increase at longer wavelengths.

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참고문헌

  1. Clavel, J., Reichert, G. A., & Alloin, D., et al., 1991, Steps Toward Determination of the Size and Structure of the Broad-line Region in Active Galactic Nuclei. I - an 8 Month Campaign of Monitoring NGC 5548 with IUE, ApJ, 366, 64 https://doi.org/10.1086/169540
  2. Gilbert, K. M. & Peterson, B. M., 2003, An Intrinsic Baldwin Effect in the H Broad Emission Line in the Spectrum of NGC 5548, ApJ, 587, 123 https://doi.org/10.1086/368112
  3. Goad, M. R., Korista, K. T., & Knigge, C., 2004, Is the Slope of the Intrinsic Baldwin Effect Constant?, MNRAS, 352, 277 https://doi.org/10.1111/j.1365-2966.2004.07919.x
  4. Ismailov, N. Z., Quliev, N. K. Khalilov, O. V., & Herbst, W., 2010, Periodic Variability in the Emission Spectrum of T Tauri, A&A 511, A13. https://doi.org/10.1051/0004-6361/200913540
  5. Kinney, A. L., Rivolo, A. R., & Koratkar, A. P., 1990, A Study of the Baldwin Effect in the IUE Data Set. Research Supported by IUE and Space Telescope Science Institute, ApJ, 357, 338 https://doi.org/10.1086/168924
  6. Korista, K. T., Alloin, D., & Barr, P., et al., 1995, Steps Toward Determination of the Size and Structure of the Broad-line Region in Active Galatic Nuclei. 8: an Intensive HST, IUE, and Ground-based Study of NGC 5548, ApJS, 97, 285 https://doi.org/10.1086/192144
  7. Markowitz, A. & Edelson, R., 2004, An Expanded Rossi X-Ray Timing Explorer Survey of X-Ray Variability in Seyfert 1 Galaxies, ApJ, 617, 939 https://doi.org/10.1086/425559
  8. Marshall, H. L., Carone, T. E., & Peterson, B. M., et al., 1997, The Variability and Spectrum of NGC 5548 in the Extreme Ultraviolet, ApJ, 479, 222 https://doi.org/10.1086/303850
  9. Nichols, J. S., & Linsky, J. L., 1996, The Final Archive and Recalibration of the International Ultraviolet Explorer (IUE) Satellite, AJ, 01,111, 517
  10. Peterson, B. M., Berlind, P., & Bertram, R., et al., 2002, Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A 13 Year Study of Spectral Variability in NGC 5548, ApJ, 581, 197 https://doi.org/10.1086/344197
  11. Peterson, B. M., Balonek, T. J., & Barker, E. S., et al., 1991, Steps Toward Determination of the Size and Structure of the Broad-line region in active galactic nuclei. II - an Intensive Study of NGC 5548 at Optical Wavelengths, ApJ 368, 119. https://doi.org/10.1086/169675
  12. Pogge, R. W. & Peterson, B. M., 1992, The Intrinsic Nature of the Baldwin Effect, AJ, 103, 1084 https://doi.org/10.1086/116127
  13. Sergeev, S. G., Doroshenko, V. T., & Dzyuba, S. A., 2007, Thirty Years of Continuum and Emission-Line Variability in NGC 5548, ApJ, 668, 708 https://doi.org/10.1086/520697
  14. Springob, C. M., Haynes, M. P., Giovanelli, R., & Kent, B. R., 2005, A Digital Archive of H I 21 Centimeter Line Spectra of Optically Targeted GalaxiesApJS, 160, 149 https://doi.org/10.1086/431550