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Spectra of GRB 970228 from the Transient Gamma-Ray Spectrometer

D. M. Palmer·T. L. Cline·N. Gehrels·K. Hurley·P. Kurczynski·N. Madden·R. Pehl·R. Ramaty·H. Seifert·B. J. Teegarden
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Abstract

Visible afterglow counterparts have now been detected for two GRBs (970228 and 970508) but are absent, with $L_{opt}/L_γ$ ratios at least two orders of magnitude lower, for other GRBs, e.g., 970828. The causes of this variation are unknown. Any correspondence which could be discovered between the gamma-ray properties of a GRB and its $L_{opt}/L_γ$ would be useful, both in determining the GRB mechanisms, and in allocating resources for counterpart searches and studies. This paper presents the gamma-ray spectra of GRB 970228 as measured by the Transient Gamma-Ray Spectrometer and comments on characteristics of this GRB compared to others that do and do not have observable counterparts.

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D. M. Palmer, T. L. Cline, N. Gehrels, K. Hurley, P. Kurczynski, N. Madden, R. Pehl, R. Ramaty, H. Seifert, B. J. Teegarden. 1998-02-02. Spectra of GRB 970228 from the Transient Gamma-Ray Spectrometer. https://doi.org/10.1063/1.55339

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