TITLE: GCN CIRCULAR NUMBER: 35613 SUBJECT: GRB 240122A: Swift/UVOT Upper Limits DATE: 24/01/23 22:57:57 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18@psu.edu> M. H. Siegel (PSU) and and V. D’Elia (SSDC & INAF-OAR) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 240122A from 29.5 ks to 35.6 ks after the MAXI trigger (Negoro et al., GCN Circ. 35593). No optical afterglow consistent with either the optical (Kumar et al., GCN Circ. 35596) or X-ray (Ambrosi et al., GCN Circ. 3600) position is detected in the initial UVOT exposures. The lack of detection in the u-band would be consistent with the redshift of 3.162 given by Saccardi et al. (GCN Circ. 35599). Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures of the candidate afterglow field are: Filter T_start(s) T_stop(s) Exp(s) Mag u 35166 35655 481 >20.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.064 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/35613. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...