Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. VI. Variability of NGC 3783 from ground-based data

• Autor(a) principal: Stirpe, Giovanna M.
• Data de Publicação: 1994
• Outros Autores: Winge, Claudia, Altieri, B., Alloin, Danielle Marie, Aguero, E.L., Anupama, G.C., Ashley, R., Bertram, R., Calderon, J.H., Catchpole, R.M., Corradi, R.L.M., Covino, E., Dottori, Horacio Alberto, Feast, M.W., Ghosh, K.K., Hutton, R. Gil, Glass, I.S., Grebel, Eva K., Jorda, L., Koen, C., Laney, C.D., Maia, Marcio Antonio Geimba, Marang, Fred, Mayya, Y.D., Morrell, Nidia, Nakada, Y., Pastoriza, Miriani Griselda, Pati, A.K., Pelat, D., Peterson, Bradley M., Prabhu, T.P., Roberts, G., Sagar, R., Salamanca, I., Sekiguchi, Kazuhiro, Storchi-Bergmann, Thaisa, Subramaniam, A., Villada, M., Wagner, R.M., Whitelock, P.A., Winkler, Hartmut, Clavel, J., Dietrich, Matthias, Kollatschny, W., Perola, G.C., Van Winckel, H., Van Wyk, Francois, O'Brien, P.T., Recondo-Gonzalez, M.C., Rodriguez-Pascual, P.M., Santos-Lleo, M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/108847
• topic: Espectros astronômicos; Galáxia NGC 3783; Nucleo galatico; Galaxias seyfert; Fotometria astronômica; Observações astronômicas no visível; Galaxies: active; Galaxies: individual (NGC 3783); Galaxies: nuclei; Galaxies: photometry; Galaxies: seyfert

The Seyfert 1 galaxy NGC 3783 was intensely monitored in several bands between 1991 December and 1992 August. This paper presents the results from the ground-based observations in the optical and near-IR bands, which complement the data set formed by the International Ultraviolet Explorer (IUE) spectra, discussed elsewhere. Spectroscopic and photometric data from several observatories were combined in order to obtain well-sampled light curves of the continuum and of Hβ. During the campaign the source underwent significant variability. The light curves of the optical continuum and of Hβ display strong similarities to those obtained with the IV E. The near-IR flux did not vary significantly except for a slight increase at the end of the campaign. The cross-correlation analysis shows that the variations of the optical continuum have a lag of 1 day or Iess with respect to those of the UV continuum, with an uncertainty of ≤4 days. The integrated flux of Hβ varies with a delay of about 8 days. These results confirm that (1) the continuum variations occur simultaneously or with a very small lag across the entire UV-optical range, as in the Seyfert galaxy NGC 5548; and (2) the emission !ines of NGC 3783 respond to ionizing continuum variations with less delay than those of NGC 5548. As observed in NGC 5548, the lag of Hβ with respect to the continuum is greater than those of the high-ionization !ines.