학술논문
A spectroscopic and photometric study of short-timescale variability in NGC 5548 ***
Document Type
Article
Author
Dietrich, M.; Bender, C. F.; Bergmann, D. J.; Bills, T. E.; Bochkarev, N. G.; Burenkov, A.; Gaskell, C. M.; Gutzmer, D. D.; Grove, R.; Hiller, M. E.; Huchra, J. P.; Klimek, E. S.; Lund, C.; Merkulova, N.; Pebley, S.; Poulsen, M. A.; Pronik, V. I.; Sergeev, S. G.; Sergeeva, E. A.; Shapovalova, A. I.; Vlasyuk, V. V.; Wilkes, B.; Dietrich, M.; Bender, C. F.; Bergmann, D. J.; Bills, T. E.; Bochkarev, N. G.; Burenkov, A.; Gaskell, C. M.; Gutzmer, D. D.; Grove, R.; Hiller, M. E.; Huchra, J. P.; Klimek, E. S.; Lund, C.; Merkulova, N.; Pebley, S.; Poulsen, M. A.; Pronik, V. I.; Sergeev, S. G.; Sergeeva, E. A.; Shapovalova, A. I.; Vlasyuk, V. V.; Wilkes, B.
Source
Astronomy and Astrophysics; May 2001, Vol. 371 Issue: 1 p79-92, 14p
Subject
Language
ISSN
00046361; 14320746
Abstract
Results of a ground-based optical monitoring campaign on NGC 5548 in June 1998 are presented. The broad-band fluxes (U, B, V), and the spectrophotometric optical continuum flux $F_\lambda$(5100 Å) monotonically decreased in flux while the broad-band Rand Ifluxes and the integrated emission-line fluxes of Hαand Hβremained constant to within 5% . On June 22, a short continuum flare was detected in the broad band fluxes. It had an amplitude of about ~18% and it lasted only ≈90 min. The broad band fluxes and the optical continuum $F_\lambda$(5100 Å) appear to vary simultaneously with the EUV variations. No reliable delay was detected for the broad optical emission lines in response to the EUVE variations. Narrow Hβemission features predicted as a signature of an accretion disk were not detected during this campaign. However, there is marginal evidence for a faint feature at $\lambda \simeq 4962$Åwith $FWHM\simeq 6$Åredshifted by $\Delta v\simeq 1100$km s-1with respect to H$\beta _{\rm narrow}$.