GRB 250704B: An Off-axis Short GRB with a Long-lived Afterglow Plateau
Authors:
- Vishwajeet SwainVSVishwajeet Swain
- Tomás AhumadaTATomás Ahumada
- Sameer K. PatilSPSameer K. Patil
- Yogesh WaghYWYogesh Wagh
- Varun BhaleraoVBVarun Bhalerao
- Ehud NakarENEhud Nakar
- Mansi KasliwalMKMansi Kasliwal
- Xander J. HallXHXander J. Hall
- Malte BusmannMBMalte Busmann
- Utkarsh PathakUPUtkarsh Pathak
- Shreya AnandSAShreya Anand
- Viraj KarambelkarVKViraj Karambelkar
Open Access
- 8 January 2026
- journal article
- Published by American Astronomical Society in The Astrophysical Journal Letters
- Vol. 996 (2) , L38
Abstract
We present a detailed multiwavelength afterglow study of the short gamma-ray burst (GRB) GRB 250704B, extensively monitored in optical and near-infrared bands. Its afterglow displays an unusually long duration plateau followed by an achromatic break and a steep decline, deviating from canonical GRB afterglows. While long plateaus are often explained by central engine activity, we find that for GRB 250704B an energy injection model requires unreasonable parameters. The afterglow is better explained by an off-axis power-law structured jet with a narrow core ( θ c ≈ 0 . ° 7) viewed at a modest angle ( θ v ≈ 1 . ° 9). A comparison with GRB 170817A shows that both events are consistent with the off-axis structured jet scenario, where the shape of the light curve is governed primarily by the geometry of the jet and the viewing angle rather than the energetics, microphysical parameters, or external density. Our results underscore the importance of incorporating the jet structure in GRB modeling.Keywords
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