TITLE: GCN CIRCULAR NUMBER: 13204 SUBJECT: GRB 120403A: Swift/BAT spectral lag analysis DATE: 12/04/03 23:35:34 GMT FROM: Takanori Sakamoto at NASA/GSFC J. Norris (BSU), T. Sakamoto (GSFC/UMBC), S.D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC) for the BAT Team: We report the spectral lag analysis for GRB 120403A (Beardmore, et al., GCN Circ. 13191) based on the BAT data. Using 64-ms binned light curves, the spectral lag for the 15-25 keV to 50-100 keV bands is 63 +380/-180 msec. Because of a relatively large error in the lag measurement due to a weak nature of the burst, we can not conclusively say that this burst is in the short burst category.