@article{f1aaf56e1cde410c9302519f8ce64106,
title = "Evidence for a Bright-edged Jet in the Optical/Near-infrared Afterglow of GRB 160625B",
abstract = "Using deep and high-cadence gamma-ray burst (GRB) afterglow data from the Reionization And Transients Infra-Red/Optical camera, we observe a sharp and achromatic light curve break 12.6 days after the GRB, accompanied by an approximately achromatic bump. Fitting of the optical, near-infrared, and X-ray data suggest a very narrow (2°) jet that remains collimated at late time. We argue that the sharp light curve bump suggests an edge-brightened jet, perhaps emitting only during a brief period of lateral jet expansion. The light curve also exhibits a gradual spectral evolution lasting >10 days. The evolution of the flux can be modeled as , with a temporal slope α = -0.956 0.003 and a gradually time-varying spectral slope .",
keywords = "gamma-ray burst: general, gamma-ray burst: individual (GRB 160625B), stars: jets",
author = "Robert Strausbaugh and Nathaniel Butler and Lee, {William H.} and Eleonora Troja and Watson, {Alan M.}",
note = "Funding Information: We thank the RATIR project team and the staff of the Observatorio Astron{\'o}mico Nacional on Sierra San Pedro M{\'a}rtir, and acknowledge the contribution of Leonid Georgiev and Neil Gehrels to its development. RATIR is a collaboration between the University of California, the Universidad Nacional Aut{\'o}noma de M{\'e}xico, NASA Goddard Space Flight Center, and Arizona State University, benefiting from the loan of an H2RG detector and hardware and software support from Teledyne Scientific and Imaging. RATIR, the automation of the Harold L. Johnson Telescope of the Observatorio Astron{\'o}mico Nacional on Sierra San Pedro M{\'a}rtir, and the operation of both are funded through NASA grants NNX09AH71G, NNX09AT02G, NNX10AI27G, and NNX12AE66G, CON-ACyT grants INFR-2009-01-122785 and CB-2008-101958, UNAM PAPIIT grant IN113810, and UC MEXUS-CONACyT grant CN 09-283. Publisher Copyright: {\textcopyright} 2019. The American Astronomical Society. All rights reserved..",
year = "2019",
doi = "10.3847/2041-8213/ab07c0",
language = "English (US)",
volume = "873",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1",
}