TITLE: GCN CIRCULAR NUMBER: 11531 SUBJECT: GRB 110106A: Swift/UVOT Upper Limits DATE: 11/01/07 00:53:06 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) and V. Mangano (INAF-IASFP) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 110106A starting 92 s after the BAT trigger (Mangano, et al., 2011, GCN Circ. 11520). Settled observations started at 110 s. We do no detect an optical afterglow in any of the UVOT filters. Preliminary 3-sigma upper limits for detecting a source in the finding charts and in the co-added images, are Filter T_start T_stop Exp(s) Mag ----------------------------------------------- white (fc) 110 162 52 >20.2 3530 3680 150 >20.3 v 3687 16,046 1278 >20.3 b 4508 10,281 1082 >21.1 u 4302 5939 393 >20.4 uvw1 4097 5734 393 >20.2 uvm2 3892 5529 393 >20.1 uvw2 4918 11,717 706 >20.9 white 110 11,194 1280 >22.0 ----------------------------------------------- The quoted magnitudes and upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.24 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627).