The interpretation of the multi-wavelength afterglow emission of short GRB 140903A

TL;DR

This paper models the multi-wavelength afterglow emission of short GRB 140903A, explaining its long-lasting radio emission and X-ray plateau through energy injection and standard fireball models, revealing that nearby SGRBs are brighter in radio.

Contribution

The study provides a detailed modeling of the afterglow emission of GRB 140903A, including the X-ray plateau and radio emission, and compares properties of SGRBs with and without radio detection, highlighting the importance of proximity.

Findings

The X-ray plateau is due to energy injection into the blast wave.

The afterglow can be modeled with reasonable physical parameters, including a jet opening angle.

Nearby SGRBs are brighter and more detectable in radio.

Abstract

GRB 140903A, a short duration $\gamma-$ray burst (SGRB) detected by {\it Swift}, is characterized by its long-lasting radio emission among SGRBs. In addition to the $\sim 10^{6}$ s radio afterglow emission, the afterglow of GRB 140903A displays a plateau from $10^3$ s to $7 \times 10^3 $ s in the X-rays. In this work, we attribute the X-ray plateau to the energy injection into the decelerating blast wave and then model the later radio/optical/X-ray afterglow emission within the standard fireball afterglow model. The afterglow emission has been well reproduced with reasonable physical parameters, including a jet half-opening angle $\sim 0.05$. We also compare the physical properties of SGRBs with and without radio afterglow detections and find that nearby SGRBs are brighter and easier to be detected in radio. Such a phenomena has been interpreted within the afterglow model.