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The 1.4 GHz light curve of GRB 970508

T. J. Galama·R. A. M. J. Wijers·M. Bremer·P. J. Groot·R. G. Strom·A. G. de Bruyn·C. Kouveliotou·C. R. Robinson·J. van Paradijs
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Abstract

We report on Westerbork 1.4 GHz radio observations of the radio counterpart to $γ$-ray burst GRB~970508, between 0.80 and 138 days after this event. The 1.4 GHz light curve shows a transition from optically thick to thin emission between 39 and 54 days after the event. We derive the slope $p$ of the spectrum of injected electrons ($dN/dγ_{e}\proptoγ_{e}^{-p}$) in two independent ways which yield values very close to $p=2.2$. This is in agreement with a relativistic dynamically near-adiabatic blast wave model whose emission is dominated by synchrotron radiation and in which a significant fraction of the electrons cool fast.

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T. J. Galama, R. A. M. J. Wijers, M. Bremer, P. J. Groot, R. G. Strom, A. G. de Bruyn, C. Kouveliotou, C. R. Robinson, J. van Paradijs. 1998-04-20. The 1.4 GHz light curve of GRB 970508. https://doi.org/10.1086/311424

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