GCN 44919: GRB 260610B: IAC-80 Optical observations

2026-06-12T07:06:28.617Z | rev 3 | event: GRB 260610B
Dominic Jackson-Horne (UOL/LJMU), Danny McDonnell (UOL/LJMU), Esme Williams (UOL/LJMU), Dafydd Thomas (UOL/LJMU), Ruby Keeling Roberston (UOL/LMJU), Farhan Qamar Salmo (UOL/LJMU), Oliver King (UOL/LJMU), Daniel Perley (LJMU), H.-M. S. Grabham (LJMU), and Daniel Harman (LJMU) report:


We observed the optical afterglow (D. O'Neill, et al., GCN 44903) of GRB 260610B (The Fermi GBM team, GCN 44901) using the 0.82m IAC-80 telescope of Teide Observatory, equipped with the CAMELOT2 optical imager.  Our first set of observations commenced at 21:41 UT and concluded at 22:20 UT on June 11; a second set of observations was then taken between 01:20 UT and 02:05 UT on June 12.

We report the following photometry:

| Date       | UTstart  | t-T0 (d) | Exp (n*s) | Filter | Mag   | Err  |
|------------|----------|----------|-----------|--------|-------|------|
| 2026-06-11 | 21:41:52 | 0.913    | 3*180     | SDSS-r | 20.04 | 0.06 |
| 2026-06-11 | 22:03:58 | 0.928    | 3*180     | Rc     | 19.85 | 0.06 |
| 2026-06-11 | 22:17:05 | 0.938    | 3*180     | Ic     | 19.23 | 0.05 |
| 2026-06-11 | 22:25:33 | 0.943    | 3*180     | B      | 20.94 | 0.13 |
| 2026-06-12 | 01:20:48 | 1.065    | 3*120     | B      | 21.47 | 0.26 |
| 2026-06-12 | 01:27:40 | 1.070    | 3*120     | V      | 20.35 | 0.09 |
| 2026-06-12 | 01:34:33 | 1.075    | 3*120     | Ic     | 19.40 | 0.08 |
| 2026-06-12 | 01:41:26 | 1.080    | 3*120     | SDSS-r | 20.26 | 0.09 |

This preliminary photometry is calibrated relative to the SDSS star J143237.88+270028.3 (using the Lupton 2005 transformation equations) and not corrected for Galactic extinction.