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GRB afterglows: from ultra-relativistic to non-relativistic phase

Y. F. Huang·Z. G. Dai·T. Lu
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Abstract

Postburst evolution of adiabatic fireballs that produce $γ$-ray bursts is studied. Emphasis has been put on the transition from the highly relativistic phase to the non-relativistic phase, which, according to our calculation, should happen much earlier than previously expected. The theoretical light curves decline a little sharper at the non-relativistic stage than at early times, but still can fit the observations well. However, disagreements are obvious when $t \ge 100$ d, implying a large initial energy $E_0$, a low interstellar density $n$, or the possible existence of a persistent energy source at the center of the fireball.

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Y. F. Huang, Z. G. Dai, T. Lu. 1998-07-07. GRB afterglows: from ultra-relativistic to non-relativistic phase. https://arxiv.org/abs/astro-ph/9807061

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