GCN 44789: GRB260601B/EP260601a: NOT near-infrared observations

2026-06-03T06:41:27.223Z | rev 0 | event: GRB 260601B

X. Liu, J. An, L.B. He, S.Q. Jiang, Z.P. Zhu, D. Xu (NAOC), S.Y. Fu (HUST), J.P.U. Fynbo (DAWN/NBI), A. M. Kadela report (NOT):

We observed the field of GRB260601B/EP260601a (Yang et al., GCN 44766; Yu et al., GCN 44767; Waratkar et al., GCN 44771; Sugita et al., 44773), using the 2.56m Nordic Optical Telescope (NOT) equipped with the NOTCam near-infrared camera. Observation started at 2026-06-03 00:53:22 UT, i.e., 29.67 hr post-burst, and 25x60s J-band frames were obtained.

The previously reported optical counterpart (Liu et al., GCN 44764; Guelfand et al., GCN 44765; Li et al., GCN 44769) was detected in our stacked image with a brightness of J = 20.7 +/- 0.1 (Vega) at a median time of 29.94 hr post-trigger, calibrated with the 2MASS catalog and not corrected for Galactic extinction.

We acknowledge the excellent support from the NOT staff, in particular A. M. Kadela.