TITLE:   GCN CIRCULAR
NUMBER:  30021
SUBJECT: GRB 210515C: Swift-BAT refined analysis
DATE:    21/05/16 02:01:46 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. D'Ai (INAF-IASFPA),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
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+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 210515C (trigger #1048618)
(D'Ai et al., GCN Circ. 30020).  The BAT ground-calculated position is
RA, Dec = 1.106, -14.972 deg which is
   RA(J2000)  =  00h 04m 25.4s
   Dec(J2000) = -14d 58' 18.2"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a weak pulse that starts at
~T-3 s, peaks at ~T+1 s, and ends at ~T+11 s, with some tail emission
lasting until ~T+60 s. T90 (15-350 keV) is 55.7 +- 26.7 sec (estimated
error including systematics).

The time-averaged spectrum from T-2.53 to T+56.90 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.26 +- 0.28.  The fluence in the 15-150 keV band is
5.9 +- 1.1 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from
T+0.84 sec in the 15-150 keV band is 0.6 +- 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/1048618/BA/