2023/06/05 by Manisha Shrestha, I. A. Steele, Shrestha, M. +11
Physics and Astronomy · #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · pdf · doi:10.48550/arxiv.2306.04649
openalex publication_date 2023/06/05 · openalex created_date 2023/06/10 · openalex updated_date 2026/07/28
GRB~210619B was a bright long gamma-ray burst (GRB) which was optically followed up by the novel polarimeter MOPTOP on the Liverpool Telescope (LT). This was the first GRB detection by the instrument since it began science observations. MOPTOP started observing the GRB 1388 seconds after the Swift Burst Alert Telescope (BAT) trigger. The R band light-curve decays following a broken power law with a break time of 2948 s after the trigger. The decay index values are α1 = 0.84 ± 0.03 (pre-break) and α2 = 0.54 ± 0.02 (post-break), indicating that the observation was most probably during the forward shock-dominated phase. We find a polarization upper limit of ∼7%. In the forward shock we expect the polarization to mostly come from dust in the local ambient medium which only produces low degrees of polarization. Hence our non-detection of polarization is as expected for this particular burst.