TITLE:   GCN CIRCULAR
NUMBER:  38602
SUBJECT: GRB 241217A: GMG Optical Upper Limit
DATE:    24/12/18 02:36:17 GMT
FROM:    Rui-Zhi Li at Yunnan Observatories, CAS <liruizhi@ynao.ac.cn>

R.-Z. Li, B.-T. Wang, F.-F. Song, J. Mao, H.-C. Feng and J.-M. Bai (YNAO, CAS) report:

We observed the field of GRB 241217A (Marius et al., GCN 38594, T0 at 2024-12-17T16:57:13) using the GMG-2.4m telescope at the Lijiang Observatory. The observation began at 2024-12-17T17:30:55, about 0.56 hours after the trigger.

No new uncataloged optical source was detected within the SVOM/VT error circle (GCN 38600).

The preliminary analysis results are shown as follows:
+----------------+------------+----------+----------------+
|  Tmid-T0 [hr]  |  Exp. [s]  |  Filter  |  5-sigma U.L.  |
+================+============+==========+================+
|      0.65      |    600     |    r     |       20.6     |
+----------------+------------+----------+----------------+
The given magnitudes are derived based on calibrating against Pan-STARRS1 field stars.