Emission line variation in the Seyfert galaxy Fairall 9 and the presence of broad O III emission.
Abstract
We present two high quality spectra of the Hβ 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) λ 5018 and λ 5169 with equal intensity. There is a strong, broad (4000 km s^-1^) wing present under the [O III] λ 5007 line, which varied only by a small amount. We show that this variation is entirely due to the variation of Fe II λ 5018 and that the remainder of the [O III]-wing has not varied. On this basis we argue that the wing is not caused by the Fe II (42) λ 5018 line, nor by any other Fe II lines, but that we observe 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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1989
- Bibcode:
- 1989A&A...211..310S
- Keywords:
-
- Emission Spectra;
- Galactic Radiation;
- Oxygen Spectra;
- Seyfert Galaxies;
- Spectrophotometry;
- H Beta Line;
- Line Spectra;
- Astrophysics