GCN Circular 22616

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. Deich (PSU),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+144 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180407A (trigger #823001)
(Deich et al., GCN Circ. 22612
Not found
 
 
). Note that due to the Sun constraint, Swift could
not slew to the burst location, and no data were collected for the burst after ~ T+144 s.
The BAT ground-calculated position is
RA, Dec = 35.236, 33.513 deg which is
  RA(J2000)  =  02h 20m 56.6s
  Dec(J2000) = +33d 30' 48.4"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 52%.

The mask-weighted light curve shows a weak pulse that starts at ~ T-20 s and
ends at ~ T+110 s. The pulse consists of several overlapping peaks. The largest
peak occurs at ~ T+2 s. T90 (15-350 keV) is 95.9 +- 29.8 sec (estimated error including
systematics). Note that because the burst went out of the BAT field of view at T+144 s,
T90 reported here might not capture the entire burst duration.

The time-averaged spectrum from T-20.58 to T+107.48 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.94 +- 0.20.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+2.18 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec.  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/823001/BA/