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A Possible Emission Feature in an X-ray Afterglow of GRB970828 as a Radiative Recombination Edge

A. Yoshida·M. Namiki·D. Yonetoku·T. Murakami·C. Otani·N. Kawai·Y. Ueda·R. Shibata·S. Uno
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Abstract

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.

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A. Yoshida, M. Namiki, D. Yonetoku, T. Murakami, C. Otani, N. Kawai, Y. Ueda, R. Shibata, S. Uno. 2001-07-18. A Possible Emission Feature in an X-ray Afterglow of GRB970828 as a Radiative Recombination Edge. https://doi.org/10.1086/323143

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