TITLE: GCN CIRCULAR NUMBER: 13480 SUBJECT: Swift-BAT refined analysis of 1E 1841-045 (Trigger=526660) DATE: 12/07/15 13:46:50 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC) (on behalf of the Swift-BAT team): Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report further analysis of 1E 1841-045 (aka Kes 73) (trigger #526660) (Barthelmy, et al., GCN Circ. 13475). The BAT ground-calculated position is RA, Dec = 280.374, -4.923 deg which is RA(J2000) = 18h 41m 29.8s Dec(J2000) = -04d 55' 23.4" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 44%. The mask-weighted light curve shows a singple spike (possibly 2 overlapping spikes) starting at ~T-0.008 and ending at ~T+0.012 sec. T90 (15-350 keV) is 0.012 +- 0.006 sec (estimated error including systematics). The time-averaged spectrum from T-0.008 to T+0.012 sec fit by a simple power-law model shows the power law index of 2.66 +- 0.40 (chi squared 50.1 for 57 d.o.f.). The fluence in the 15-150 keV band is 1.2 +- 0.3 x 10^-8 erg/cm2. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 8.77 +- 1.67 keV (chi squared 40.8 for 59 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/526660/BA/ We note the previous activity of this source: Swift BAT triggers 456505 on 02 Jul 2011 (GCN 12103 & 12104), 455904 on 23 Jun 2011 (GCN 12079 & 12082), and 445776 on 11 Feb 2011 (GCN 11673).