  A gamma-ray burst of 28 August 1997 was localized by the All-Sky Monitor on
the Rossi XTE satellite and its coordinates were promptly disseminated. An ASCA
followup started 1.17 days after the burst as a Target of Opportunity
Observation and detected an X-ray afterglow. The spectral data displayed a hump
around ~5 keV and an absorption column of 7.1 x 10^21 cm^{-2}. This hump
structure is likely a recombination edge of iron in the vicinity of the source,
taking account of the redshift z = 0.9578 found for the likely host galaxy of
the associated radio flare. Radiative Recombination edge and Continuum model
can interpret the spectrum from highly ionized plasma in a non equilibrium
ionization state. The absorption could be also due to the medium presumably in
the vicinity of the GRB.
