GCN Circular 42253
A. Reguitti (INAF/OAPd) reports on behalf of a larger collaboration:
I observed the field of GRB 251013C (Fermi GBM Team, GCN 42221; Rakotondrainibe et al., GCN 42222) using the 67/92 Schmidt Telescope located at the Asiago observatory (Italy). Observations were carried out using Sloan r and i filters.
The optical counterpart (Palmerio et al., GCN 42223; Perez-Garcia et al., GCN 42225; Konno et al., GCN 42226; Martin-Carrillo et al., GCN 42227; Masi, GCN 42228; Palmerio et al., GCN 42229; Moskvitin et al., GCN 42230; Gompertz et al., GCN 42231; Garnavich, GCN 42240; Watson et al., GCN 42241; López-Cámara et al., GCN 42242; Brosio et al., GCN 42251) is clearly detected in our frames. At mean epoch 2025 Oct 13.85 UT (2.75 hr after the GRB), I measure AB magnitudes r = 16.51 +- 0.05 and i = 16.27 +- 0.04 (calibrated against magnitudes from the Pan-STARRS catalog).