R. Brivio, M. Ferro, P. D'Avanzo, D. Fugazza (INAF-OAB), A. Melandri (INAF-OAR), S. Covino (INAF-OAB)
on behalf of the REM team, report:
We observed the field of GRB 221009A (Dichiara et al., GCN 32632; Kennea & Williams, GCN 32635; Veres et al.,
GCN 32636; Bissaldi et al., GCN 32637; Svinkin et al., GCN 32641; Ursi et al., GCN Circ. 32650) with the REM
60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were carried in the
g, r, i, z, J, H and K bands, starting on 2022 Oct 09 at 23:43:02 UT (i.e. about 10.43 hours after the GBM trigger)
and lasted for about 1 hour.
The optical and NIR afterglow is detected in all bands. From preliminary photometry, we derive the following magnitudes:
r = 17.36 +/- 0.12
(AB; calibrated against the the Pan-STARRS catalogue)
H = 12.21 +/- 0.04
(Vega; calibrated against the 2MASS catalogue)
at a mid time of t-t0 ~ 10.47 hours after the GBM trigger.