TITLE:   GCN CIRCULAR
NUMBER:  30092
SUBJECT: GRB 210527A: Swift-BAT refined analysis
DATE:    21/05/28 22:26:49 GMT
FROM:    Sibasish Laha at GSFC  <sibasish.laha@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), 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 210527A (trigger #1051453)
(Laha et al., GCN Circ. 30081).  The BAT ground-calculated position is
RA, Dec = 172.346, 31.627 deg which is
   RA(J2000)  =  11h 29m 23.0s
   Dec(J2000) = +31d 37' 37.0"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 90%.

The BAT light curve showed a complex structure with a duration of about ~70 sec.
T90 (15-350 keV) is 63.21 +- 11.15 sec (estimated error including systematics).

The time-averaged spectrum from T-17.07 to T+62.45 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.33 +- 0.26.  The fluence in the 15-150 keV band is 6.5 +- 1.0 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+17.86 sec in the 15-150 keV band
is 0.4 +- 0.1 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/1051453/BA/