TITLE: GCN CIRCULAR NUMBER: 8740 SUBJECT: GRB 081226B: Swift XRT and UVOT upper limits DATE: 08/12/27 10:02:56 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) and E.A. Hoversten (PSU) report on behalf of the Swift team: Swift observed the field of GRB 081226B (Mereghetti et al. GCN Circ 8734) for 8 ks, beginning 9.6 ks after the INTEGRAL trigger. The XRT data (all in Photon Counting mode) contain no source in the INTEGRAL error circle. A 3-sigma upper limit is 0.001 counts/sec which is 5.6e-14 erg cm^-2 s^-1 for a typical GRB spectrum. Given the absence of an XRT position, the UVOT images were compared to archival images from the Digitized Sky Survey. No candidate afterglow was found in the INTEGRAL error circle. UVOT magnitude 3-sigma upper limits are reported in the following table: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- WHITE 9744 22737 1414 > 22.24 v 9621 27619 1940 > 20.48 b 9720 21824 1414 > 21.06 u 9694 16082 352 > 20.34 uvw1 10019 15877 313 > 20.20 uvm2 15472 28224 787 > 20.75 uvw2 10812 23271 932 > 21.27 The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.01 mag. All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627). This circular is an official product of the Swift XRT and UVOT teams.