The Long-lived Broadband Afterglow of Short Gamma-Ray Burst 231117A and the Growing Radio-Detected Short GRB Population

We present multiwavelength observations of the Swift short -ray burst GRB 231117A, localized to an underlying galaxy at redshift z = 0. 257 at a small projected offset (2~kpc). We uncover long-lived X-ray (Chandra) and radio/millimeter (VLA, MeerKAT, and ALMA) afterglow emission, detected to 37~days and 20~days (rest frame), respectively. We measure a wide jet (10. 4^) and relatively high circumburst density (0. 07~ cm^-3) compared to the short GRB population. Our data cannot be easily fit with a standard forward shock model, but they are generally well fit with the incorporation of a refreshed forward shock and a reverse shock at 10^-2~ cm^-3), consistent with their smaller (10^) jets where observational evidence of collimation may only be detectable at radio wavelengths. Owing to improved observing strategies and the emergence of sensitive radio facilities, the number of radio-detected short GRBs has quadrupled in the past decade.