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For refcode 1995ApJ...454L.105M:
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1995ApJ...454L.105M ACTIVE GALACTIC NUCLEI DISK WINDS, ABSORPTION LINES, AND WARM ABSORBERS N. MURRAY AND J. CHIANG Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ont MSS IA7, Canada Received 1995 March 21; accepted 1995 September 7 ABSTRACT The broad (10-30,000 km s^-1^) UV absorption lines seen in some quasars can form in a radiatively driven wind. The driving operates on UV resonance lines of moderately ionized metals and is efficient at high velocity because the wind shields itself from soft X-rays emitted by the central source. This shielding is a natural consequence of the high- ionization parameter U = n_{gamma}_/n ~ 10 and column (10^23^ cm^-2^) at the inner edge of the wind. Compared to radio-quiet quasars, both radio-loud quasars and Seyfert nuclei are strong X-ray emitters (relative to their UV emission), so their winds are less well shielded. This tends to limit the width of blueshifted absorption in UV resonance lines such as C IV. This effect is enhanced in Seyferts by the lower wind column densities (10^22^ cm^-2^), a result of their lower luminosity. We predict that active galactic nuclei with intrinsic, broad (~>500 km s^-1^) blueshifted absorption in C IV will also have absorption edges near 1 keV due to O VII and/or O VIII. Objects with very broad C IV absorption (~>5000 km s^-1^) will be strongly absorbed at 1 keV and will also have Fe absorption edges. We suggest that the gas at the inner edge of the wind should be identified with the "warm absorber" found in objects showing blueshifted absorption in UV resonance lines. Subject headings: galaxies: Seyfert - quasars: absorption lines
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