TITLE: GCN CIRCULAR NUMBER: 16771 SUBJECT: GRB 140903A: Swift-BAT Spectral lag analysis DATE: 14/09/04 06:32:31 GMT FROM: Takanori Sakamoto at AGU T. Sakamoto (AGU), J. Norris (BSU), S. D. Barthelmy (GSFC), N. Gehrels (GSFC) report: We report the spectral lag analysis for GRB 140903A (GCN Circ. 16764 & 16765) based on the BAT data. Using 4-ms binned light curve, the spectral lag for the 50-100 keV to 100-350 keV bands is 16 +- 7 ms, and 21 +- 7 ms for the 15-25 keV to 50-100 keV bands. There is no evidence for extended emission. Those lag values are consistent with the short end of the long-burst lag distribution. Although the lag analysis suggests GRB 140903A is consistent with a long GRB population, a further observation is needed to understand the nature of this burst.