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- Stirpe, G. M., et al.
(författare)
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Broad emission line variability in the Seyfert 1 galaxies NGC 5548 and NGC 3783
- 1988
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 200:1-2, s. 9-1616
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Tidskriftsartikel (refereegranskat)abstract
- High quality spectra are presented for the Seyfert 1 galaxies NGC 5548 and NGC 3783. Halpha and Hbeta were observed at different epochs, with time intervals between 4 and 13 months. The spectra have been scaled to each other by normalizing the flux of the narrow lines. The difference spectra show that the broad emission lines have varied not only in flux, but also in shape. The authors compare their data with those published by Peterson (1987) and Peterson et al. (1987) and conclude that the supermassive binary scenario proposed by the latter is not unique. The observed variations can be interpreted in an accretion disk scenario. The whole data-set also provides evidence against models based on outflowing motion. The He II lambda4686 line discussed together with N III lambda4640 Bowen emission. A limit to the results is given by the long time intervals separating the observations, which do not allow the authors to set as strong constraints on the BLR as high quality, frequent monitoring of Seyfert 1 spectra would
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| 2. |
- Stirpe, G. M., et al.
(författare)
-
Emission line variation in the Seyfert galaxy Fairall 9 and the presence of broad [O III] emission
- 1989
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 211:2, s. 310-314314
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Tidskriftsartikel (refereegranskat)abstract
- The authors present two high quality spectra of the Hbeta region in the Seyfert 1 galaxy Fairall 9, separated by a period of 4 years. The variation of the broad lines is discussed, and in particular that of the Fe II lines of multiplet 42. The difference spectrum shows clearly Fe II (42) lambda 5018 and lambda 5169 with equal intensity. There is a strong, broad (4000 km s -1) wing present under the [O III] lambda 5007 line, which varied only by a small amount. The authors show that this variation is entirely due to the variation of Fe II lambda 5018 and that the remainder of the [O III]-wing has not varied. On this basis the authors argue that the wing is not caused by the Fe II (42) lambda 5018 line, nor by any other Fe II lines, but that they are observing high velocity [O III]-emitting material. From the lack of variation in this component a minimum distance to the source can be set of 1.3 pc. Other features of the difference spectrum are also discussed
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