Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 1. An 8 month campaign of monitoring NGC 5548 with IUE

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.

doi:10.1086/169540

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 1. An 8 month campaign of monitoring NGC 5548 with IUE

J. Clavel
(
- Madrid Observ. and
- NASA, Goddard
)
,
G.A. Reichert
(
- Madrid Observ. and
- NASA, Goddard
)
,
D. Alloin
(
- Madrid Observ. and
- NASA, Goddard
)
,
D.M. Crenshaw
(
- Madrid Observ. and
- NASA, Goddard
)
,
G. Kriss
(
- Madrid Observ. and
- NASA, Goddard
)

1991

18 pages

Published in:

Astrophys.J. 366 (1991) 64-81

DOI:

10.1086/169540

View in:

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Abstract: (ADS)

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. Associated Articles Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7 Part 8 Part 9 Part 10 Part 11 Part 14 Part 13 Part 12 Part 15

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