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   62158
   We propose offset observations of A2199 and A496 - relaxed, typical in
   every respect, cooling flow clusters - to measure their mass profiles
   with unprecedented accuracy. These clusters are selected from a set of
   about 30 for which we have obtained temperature distributions with
   ASCA. Featureless temperature maps of their central regions indicate
   that they are good candidates for hydrostatic mass determinations. At
   z=0.03, the proposed angular offsets will cover interesting radii,
   while the complicating effects of the PSF and stray light will be
   minimal. These two clusters are among those few for which such
   measurements are feasible with ASCA. They will be vital members of a
   representative set of cluster mass profiles needed for addressing
   interesting cosmological issues.
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