TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3429 SUBJECT: No Swift-BAT Lightcurves in real-time for next 3 weeks DATE: 05/05/19 18:11:11 GMT FROM: David Palmer at LANL D. Palmer (LANL), S. Barthelmy, L. Barbier (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: On 17 May 2005, a problem was discovered in the Swift-BAT flight software. This problem causes the lightcurves generated on or after 10 May 2005 that are sent down the real-time TDRSS telemetry link to contain incorrect data. This problem affects only the BAT Lightcurve -- the BAT burst RA,Dec positions are unaffected, as are all the other BAT data products. TDRSS light curves generated before 10 May 2005 were unaffected. The only corrupted light curve that has been distributed via GCN was for the 'Interesting Source' trigger 122203 on 17 May 2005. A localized problem in the handling of on-board time causes the flight software to produce totally incorrect light curve rates. The fix is being included in the flight software upload that will happen around the week of 30 May 2005. Until then, the distribution of BAT Lightcurve Notices will be blocked. All the other GCN/Swift Notice types will continue to be distributed. We regret any inconvenience that this may cause.