TITLE:   GCN CIRCULAR
NUMBER:  44843
SUBJECT: GRB 260604C: Liverpool Telescope optical detection
DATE:    26/06/05 14:01:06 GMT
FROM:    Dimple  at University of Birmingham <dimplepanchal96@gmail.com>

B. P. Gompertz (U. Birmingham), D. B. Malesani (DAWN/NBI and Radboud)  and Dimple (U. Birmingham) report on behalf of a larger collaboration:

We conducted follow-up observations of GRB 260604C (Fermi Team, GCN Circ. 44822, Gotz et al., GCN Circ. 44823) with the IO:O camera on the 2m robotic Liverpool Telescope (LT). Observations began at 00:14:01 UT on 2026-06-05, ~3.92 hr after the burst, and consisted of 5 x 120 s exposures in each of the SDSS r, g, i and z filters.

We detect the optical counterpart (Lipunov et al., GCN 44827; Konno et al., GCN 44828; Zhu et al., GCN 44832, Becerra et al., GCN 44834; Hellot et al., GCN 44835; Gompertz et al. 44837) in all the filters, and measure an AB magnitude of r = 18.60 ± 0.05.

Magnitudes are calibrated against nearby Pan-STARRS stars and are not corrected for Galactic extinction.