TITLE: GCN CIRCULAR NUMBER: 9153 SUBJECT: GRB 090417B: Swift-BAT further refined analysis DATE: 09/04/18 15:31:19 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-IASFPA) (for the Swift-BAT team): Continuing the analysis for BAT GRB 090417B (trigger #349450) (Cummings, GCN Circ 9139) using more downlinked data, we report that this burst is very long. The revised mask-weighted light curve starts before T-200 sec (where we start collecting event data on each trigger), slowly rises to a peak around T+400 sec and slowly decreases to a minumum around T+1100 sec, then increases to a second maximum around T+1650 sec, and then decreases again with continuing emission past T+2100 sec (where the data stops). The amplitudes of the two peaks are 0.09 +- 0.01 and 0.060 +- 0.006 ph/cm2/sec, resp.