GCN Circular 21142

S. D. Barthelmy (GSFC), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
and T. Sakamoto (AGU), report on behalf of the Swift Team:

At 10:40:40 UT on 2017-05-24, the Swift Burst Alert Telescope (BAT) triggered on
GRB 170524B (trigger=754265).  However, on-board analysis was truncated by
a pre-planned slew to a scheduled target.  Subsequent ground analysis
using data from T+2 to T+101 s finds the source at a location of
RA, Dec 90.864, -17.086, which is
RA(J2000)  =  06h 03m 27s
Dec(J2000) = -17d 05' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty).

The BAT light curve shows a complex structure about 50 seconds long.
The raw peak count rate was ~18000 counts/sec (15-350 keV), at ~7 sec after
the trigger. T90 (15-350 keV) estimated using the raw light curve is 46.4 +- 1.6 sec
(estimated error including systematics).

The time-averaged spectrum from T+1.8 to T+49.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.15 +- 0.06.  The fluence in the 15-150 keV band is (6.6 +/- 0.2) x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+6.70 sec in the 15-150 keV band
is 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

This event was also detected by CALET, KONUS-Wind, and INTEGRAL SPI ACS.

A Swift Target of Opportunity observation has been requested.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/00753445006/BA/