TITLE:   GCN CIRCULAR
NUMBER:  40684
SUBJECT: GRB 250610B: additional Liverpool Telescope optical observations
DATE:    25/06/11 08:39:42 GMT
FROM:    A. Bochenek at Liverpool John Moores University <a.m.bochenek@2023.ljmu.ac.uk>

A. Bochenek and D. A. Perley (LJMU) report:
 
We observed the field of GRB 250610B (Saccardi et al., GCN 40671) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 4x100s exposures in the SDSS r’ and i’ filters starting at 2025-06-10 23:34:02 UT, approximately 7.0 hours after the trigger.
 
We report detections in stacked images in both filters at the position of the reported optical counterpart (Schneider et al., GCN 40676). The obtained magnitudes are r = 21.21 ± 0.11 and i = 21.14 ± 0.13, in line with previous optical observations (Schneider et al., GCN 40676; Gompertz et al., GCN 40677; Li et al., GCN 40678). The photometry was calibrated using nearby PanSTARRS secondary standards and was not corrected for extinction.

MJD (mid)          T_mid-T_0        Filter       Mag. (AB)
60836.98618        7.12 h            r          21.21 ± 0.11
60836.99384        7.30 h            i          21.14 ± 0.13