GCN Circular 45913
Subject
GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
Event
Date
2026-10-12T00:22:24Z (11 hours ago)
Edited On
2026-10-12T01:56:22Z (9 hours ago)
From
Jianhong Cao at Sun Yat-sen University <caojh35@mail2.sysu.edu.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Jianhong Cao at Sun Yat-sen University <caojh35@mail2.sysu.edu.cn>
Via
Web form
Si-Rui Huang, Jin-Ji Li, Zhong-Nan Dong, Jia-Qi Lin, Pu Lin, Yun Shi, Jian-Hong Cao, Hao-Nan Yang, Rui-Chen Gao, Jing-Kai Sun, Hao-Ran Zhang, P H Thomas Tam, Rong-Feng Shen, Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm infrared telescope team:
We observed the field of GRB 261011A, detected by SVOM/ECLAIRs (Huang et al., GCN 45895) and Swift/BAT (Cenko et al., GCN 45896), using the Sun Yat-sen University (SYSU) 80cm infrared telescope. Our observations were carried out on 2026 Oct 11 from 16:27:30 to 17:07:28 UT, approximately 2.68–3.35 hours after the Swift/BAT trigger, using stacked images in the J band.
We clearly detect the near-infrared afterglow at the position of the previously reported optical counterpart (Cenko et al., GCN 45896; O'Neill et al., GCN 45897). The photometric results are listed below (times refer to the midpoints of the observations):
* **16:37:14 UT (T0 + 2.84 hr):** 58 x 20 s (1160 s total exposure), J = 18.07 +/- 0.07 mag (Vega).
* **16:57:34 UT (T0 + 3.18 hr):** 59 x 20 s (1180 s total exposure), J = 18.65 +/- 0.14 mag (Vega).
The source shows a decline of approximately 0.58 mag between the two epochs.
The photometry was calibrated against nearby stars from the 2MASS catalog and is reported in the Vega system, without correction for Galactic extinction.
An additional approximately one hour of J-band observations was obtained, and the data are currently being processed.
The SYSU 80 cm infrared telescope is operated and managed by the Department of Astronomy, Sun Yat-sen University.