GCN Circular 38642
Subject
GRB 241217A/EP241217b: SOAR afterglow detection
Date
2024-12-19T23:44:16Z (20 days ago)
From
James Freeburn at Swinburne University of Technology <jamesfreeburn54@gmail.com>
Via
Web form
J. Freeburn (Swinburne/OzGrav), I. Andreoni (UNC), J. Carney (UNC)
We observed the optical counterpart (Qiu et al., GCN 38600) to SVOM GRB 241217A / EP241217b (Brunet et al., GCN 38594; William et al., GCN 38599; Zhou et al., GCN 38606), with the Goodman High Throughput Spectrograph mounted on the SOAR telescope in imaging mode. We took six 300s exposures in r-band between 2024-12-19T04:23:12 and 2024-12-19T04:54:57 UTC.
We detect the optical counterpart associated with GRB 241217A / EP241217b. With difference imaging using a template from the Dark Energy Survey (Abbott et al., 2021, ApJ, 255, 20) and photometric calibration using the Pan-STARRS1 catalogue, we measure r = 24.28 +/- 0.26 AB magnitude.
While this is a low significance result, our measurement agrees with the photometry reported in Schneider et al. (GCN 38637). Measuring from the science and template images respectively, we obtain 23.41 +/- 0.14 and 24.49 +/- 0.18 AB magnitude respectively. These measurements are consistent with the results of GCN 38637 and the Legacy Survey catalog measurement.