TITLE: GCN CIRCULAR NUMBER: 8982 SUBJECT: GRB 090309, Swift-BAT lag analysis DATE: 09/03/13 09:58:16 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (GSFC/UMBC), J. P. Norris, T. N. Ukwatta (GWU/GSFC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC), M. Stamatikos (GSFC/ORAU) (for the Swift-BAT team): For GRB 090309 (Evans et al. GCN Circ. 8964), we are unable to determine if this is a short or long burst. The reasons are as follows: (1) the spectral lag is 0.044 +/- 0.16 sec (between the 50-100 and 15-25 keV). (2) The T90 duration is 3.0 +- 1.4 sec (Palmer et al. GCN Circ. 8967) which is midway between the two T90 distributions. (3) The photon index is 1.36 +/- 0.33 (Palmer et al. GCN Circ. 8967) is also in the middle of the short and hard distributions (Figure 13 of Sakamoto et al., ApJS, 175, 179).