Abstract

Thirteen years of IUE observations of the Seyfert 1 galaxy Fairall-9 have shown a large variability in the UV continuum and UV emission lines, Lyαλ1216 and CIVλ1550. The relation between UV continuum and X-ray (no delay) is similar to that found for lower luminosity objects and suggests that X-ray reprocessing causes the UV continuum. We also use the line variability to support and refine a gaussian decomposition of the profiles of Lyα and CIV, based on a previous study of Hβ. The decomposition of Lyα and CIV shows a well identified component structure valid for both lines. The components respond very differently to the changes in the ionizing continuum brightness, confirming the different physical nature of the material associated with them.

The UV-X ray continuum relation

We show in figure 1 (1a and 1b) the UV and X-ray light curves of F-9, while fig. 1c and 1d show relations between these two quantities. Although the time resolution in the CCF (1d) is of course limited by the sparse X-ray sampling no evidence is found for delays of the size suggested by the IR (400 days). We see here also that at high UV brightness the rather tight correlation between the 2-10 keV flux and F(1338Å) breaks down. Although the details of this behaviour are currently not fully understood it has been suggested that at low levels the UV continuum is the result of reprocessing of X-rays emitted above the disk while the huge UV variations could be associated with major accretion events.