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   72121
   The upcoming AXAF observations are likely to change our view of AGN. In
   particular, grating spectroscopy is likely to reveal the nature of the
   highly ionized gas in such objects. Unfortunately, there are
   fundamental ambiguities in the single-shot, pointed observations that
   are impossible to resolve without a careful monitoring of the targets
   prior to the AXAF observation. Such monitoring is essential to
   understand the ionization history of the sources and to enable a real
   modeling, including light travel time and luminosity dependent effects.
   We propose six 20ksec ASCA observations of NGC3516 over a 10 day period
   prior to our AXAF observation. The proposal shows the enhanced science
   likely to result from such a combined ASCA-AXAF campaign, as well as
   the independent ASCA science.
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