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GCN Circular 23836

Subject
GRB 190202A, Swift-BAT refined analysis
Date
2019-02-02T19:42:08Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), 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+400 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 190202A (trigger #887217)
(Lien et al., GCN Circ. 23830).  The BAT ground-calculated position is
RA, Dec = 166.506, 9.393 deg which is
  RA(J2000)  =  11h 06m 01.4s
  Dec(J2000) = +09d 23' 33.9"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 4%.

The mask-weighted light curve shows two overlapping pulses that start
at ~T0 and end at ~T+25 s. The two peaks occur at ~T0 and ~T+5 s, respectively,
Note that the burst location came into the BAT field of view at ~T-69 s, and Swift
went into SAA at ~T+210 s. T90 (15-350 keV) is 19.4 +- 6.9 sec (estimated
error including systematics).

The time-averaged spectrum from T-0.90 to T+26.52 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.32 +- 0.13.  The fluence in the 15-150 keV band is 6.0 +- 0.5 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+4.68 sec in the 15-150 keV band
is 7.8 +- 1.5 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/887217/BA/
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