Abstract
EUVE observations of the Seyfert 1 galaxy NGC 5548 have shown the presence of line emission features identified as a Ne VII/Ne VIII blend at 88 Å and Si VII emission at 70 Å. The lines show significant broadening (FWHM 3800 km s-1) placing the emitting region at the same distance as the inner broad-line region. A fit to a thermal plasma yields a temperature of 6 × 105 K. The line emission can be attributed to the warm absorbing material discovered before from oxygen and iron absorption features, which appears to be an optically thin (for the Lyman continuum), highly ionized phase of the broad-line region.
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Kaastra, J.S., Mewe, R., Roos, N. (1996). Line Emission from Warm Material in NGC 5548. In: Bowyer, S., Malina, R.F. (eds) Astrophysics in the Extreme Ultraviolet. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-3988-5_9
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