TITLE:   GCN CIRCULAR
NUMBER:  22705
SUBJECT: GRB 180510B: Swift-BAT refined analysis
DATE:    18/05/11 14:30:53 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

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

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180510B (trigger #831816)
(Tohuvavohu et al. GCN Circ. 22696).  The BAT ground-calculated position is
RA, Dec = 77.965, -62.320 deg which is
  RA(J2000)  =  05h 11m 51.6s
  Dec(J2000) = -62d 19' 13.0"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.

The mask-weighted light curve shows a weak pulse that starts at ~T-20 s and peaks
at ~T+1 s. The main pulse ends at ~ T+40 s, and there is some low-level emission
that lasts until ~T+140 s. T90 (15-350 keV) is 134.3 +- 48.2 sec (estimated error including systematics).

The time-averaged spectrum from T-19.92 to T+137.10 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.00 +- 0.17.  The fluence in the 15-150 keV band is 2.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.96 sec in the 15-150 keV band
is 1.2 +- 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/831816/BA/