LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits

Swift has carried out observations of the error region of the BAT-GUANO candidate counterpart, which was detected 11.2641 s after T0 of S241125n (DeLaunay et al., GCN Circ. 38308). Swift-UVOT observations were carried out using the White filter for a total of 4.8 ks, spanning from 55 ks to 74 ks after the LVC trigger. No new/uncatalogued sources were detected within the BAT-GUANO localization (RA, Dec = 58.079, +69.689 deg, r=5', 50% containment; GCN Circ. 38308), with an average 3sigma limit on the magnitude >23.2 (AB; White filter). As reported by Evans et al. (GCN Circ. 38324), 5 X-ray sources were seen. However, none of these sources were detected with UVOT. S241125n_X1 and S241125n_X2 were located outside of UVOT's field of view. S241125n_X3 was not detected, with a 3sigma limit on the magnitude (AB) >23.16. S241125n_X4's position was heavily contaminated by image artifacts and coincidence loss from a bright nearby source. S241125n_X5 was not detected, though its position was also affected by an image artifact from a bright nearby source, though to a lesser degree. The precise upper limit at this location can not be accurately determined, but can be approximated as >23. This circular is an official data product of the Swift-UVOT team.