S.Q. Jiang, X. Liu, S.Y. Fu, J. An, Z.P. Zhu, T.H. Lu, D. Xu (NAOC), L.F. Huo, S.W. Luo, M.M. Yang, Z. K. Feng (GYZO) report:
We observed the field of GRB 231115A, a short GRB detected by the Fermi GBM (Fermi GBM Team, GCN 35035), INTEGRAL (Mereghetti et al., GCN 35037), and Glowbug (Cheung et al., GCN 35045), using the GOT-0.5m telescope located at Gaoyazi, Xinjiang, China. Observations started at 16:36:59 UT on 2023-11-15, i.e., 1.01 hr after the Fermi/GBM trigger, and we obtained 40x60 s frames in the Sloan r-filter and 40x90 s frames in the Sloan z-filter.
No credible optical transient is detected in our stacked images within and beside the error region of the INTEGRAL by the means of catalogue cross-match and image subtraction, down to 3-sigma limiting magnitudes of r>20.1 @ 1.38 hr and z>18.0 @ 2.86 hr post-burst, calibrated with nearby PanSTARRS stars. The magnitude is not corrected for Galactic extinction.
The field is also covered by the GW survey program at the GOT. The latest template was taken on 2023-10-05 and it gives upper limit down to r>18.8 within the INTEGRAL/IBAS error region.