TITLE:   GCN CIRCULAR
NUMBER:  31899
SUBJECT: GRB 220412A: Swift-BAT refined analysis
DATE:    22/04/13 21:01:24 GMT
FROM:    Tyler Parsotan at UMBC/GSFC/CRESST II  <parsotat@umbc.edu>

T. Parsotan (GSFC/UMBC), S. D. Barthelmy (GSFC), 

H. A. Krimm (NSF), S. Laha (GSFC/UMBC),

A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),

D. M. Palmer (LANL), T. Sakamoto (AGU),

M. Stamatikos (OSU) (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 220412A (trigger #1102281)

(Klingler et al. GCN Circ. 31881).  The BAT ground-calculated position is

RA, Dec = 123.975, 30.336 deg which is 

   RA(J2000)  =  08h 15m 54.0s 

   Dec(J2000) = +30d 20' 08.5" 

with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 92%.

 

The BAT light curve showed a complex

structure with a duration of about 20 sec.  The peak count rate

was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger.

T90 (15-350 keV) is 41.66 +- 7.00 sec (estimated error including systematics).

 

The time-averaged spectrum from T-11.07 to T+38.00 sec is best fit by a simple

power-law model.  The power law index of the time-averaged spectrum is

1.53 +- 0.21.  The fluence in the 15-150 keV band is 5.9 +- 0.9 x 10^-07 erg/cm2.

The 1-sec peak photon flux measured from T+6.88 sec in the 15-150 keV band

is 0.5 +- 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/1102281/BA/