TITLE: GCN CIRCULAR NUMBER: 8017 SUBJECT: GRB080723B: Swift/UVOT Upper Limits DATE: 08/07/25 13:03:18 GMT FROM: Peter Brown at PSU P. J. Brown (Penn State) reports on behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 080723B (Gotz et al., GCN Circ. 8002) starting at 2008-07-23 17:05:44, 13.4 ks after the Integral detection. We do not find any source in the UVOT observations at the XRT position of the afterglow (Page, GCN Circ. 8008). The 3-sigma upper limits for detecting a source at this location in the co-added images are: Filter T_start(s) T_stop(s) Exp(s) Mag(3-sigma upper limit) v 13790 13836 45 >18.1 b 13551 35434 473 >20.3 u 13500 35220 661 >20.1 uvw1 13405 40586 1538 >20.4 uvm2 13841 13966 124 >18.8 uvw2 13603 35801 735 >20.1 The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). They have not been corrected for the expected high but uncertain Galactic extinction along the line of sight (Galactic latitude < 5 degrees).