Bibcode
DOI
Clavel, J.; Reichert, G. A.; Alloin, D.; Crenshaw, D. M.; Kriss, G.; Krolik, J. H.; Malkan, M. A.; Netzer, H.; Peterson, B. M.; Wamsteker, W.; Altamore, A.; Baribaud, T.; Barr, P.; Beck, S.; Binette, L.; Bromage, G. E.; Brosch, N.; Diaz, A. I.; Filippenko, A. V.; Fricke, K.; Gaskell, C. M.; Giommi, P.; Glass, I. S.; Gondhalekar, P.; Hackney, R. L.; Halpern, J. P.; Hutter, D. J.; Joersaeter, S.; Kinney, A. L.; Kollatschny, W.; Koratkar, A.; Korista, K. T.; Laor, A.; Lasota, J.-P.; Leibowitz, E.; Maoz, D.; Martin, P. G.; Mazeh, T.; Meurs, E. J. A.; Nair, A. D.; O'Brien, P.; Pelat, D.; Perez, E.; Perola, G. C.; Ptak, R. L.; Rodriguez-Pascual, P.; Rosenblatt, E. I.; Sadun, A. C.; Santos-Lleo, M.; Shaw, R. A.; Smith, P. S.; Stirpe, G. M.; Stoner, R.; Sun, W. H.; Ulrich, M.-H.; van Groningen, E.; Zheng, W.
Bibliographical reference
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 366, Jan. 1, 1991, p. 64-81.
Advertised on:
1
1991
Journal
Citations
513
Refereed citations
438
Description
Emission-line and UV continuum observations of the type I Seyfert galaxy
NGC 5548 were carried out for a period of 8 months with the IUE
satellite. It was found that both the continuum shape and the line
ratios of NGC 5548, while being not unusual for type I Seyfert galaxies,
are strongly variable. The UV continuum flux and broad emission line
fluxed went through three large maxima and three deep minima; the ratio
of miximum to minimum flux was about 4.5 for the continuum at 1350 A.
The N V and the He II emission lines exhibited maximum-to-minimum flux
ratios as high as those of the continuum; other ionization lines
(Ly-alpha, C IV, and C III) exhibited smaller amplitude fluctuations,
with the smallest being recorded for the Mg II line (about 1.3). It was
found that, except for Mg II, the emission-line variations correlated
extremely well with those of the 1350-A continuum.