GCN Circular 5899
F.E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team: The exposure times for UVOT were reported incorrectly for GRB 061110B in GCN Circ. 5803 and for GRB 061121 in GCN Circ. 5823 because of a configuration problem in the instrument. The actual exposure times are close to the nominal values of 100 s and 400 s (Page et al., GCN Report 15.1) respectively. We caution users of UVOT data that data in the archives for exposures taken between November 10 and November 22, 2006, have an incorrect value for the frame time. As a consequence, the standard UVOT analysis tools do not calculate dead time and anti-coincidence losses properly. Additional details, including the proper technique for analyzing these data, are available on the following web page: http://heasarc.gsfc.nasa.gov/docs/swift/uvot_frame.html.