[vsnet-grb-info 22800] GRB 190627A: Swift-BAT refined analysis (short-soft burst)

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24899
SUBJECT: GRB 190627A: Swift-BAT refined analysis (short-soft burst)
DATE:    19/06/28 15:01:57 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm at nsf.gov>

S. D. Barthelmy (GSFC),  J. R. Cummings (CPI), H. A. Krimm (NSF),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.),  M. Stamatikos (OSU),
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 190627A (trigger #911609)
(Sonbas, et al., GCN Circ. 24888).  The BAT ground-calculated position is
RA, Dec = 244.843, -5.302 deg which is 
  RA(J2000)  =  16h 19m 22.3s 
  Dec(J2000) = -05d 18' 08.6" 
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.

The mask-weighted light curve shows a single peak, visible only in the softest
energy channels, with a duration of about four seconds.  The burst location
went out of the BAT field soon after T+400 sec due to a spacecraft slew.
T90 (15-350 keV) is 1.60 +- 0.28 sec (estimated error including systematics).

The time-averaged spectrum from T+0.04 to T+1.78 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.38 +- 0.38.  The fluence in the 15-150 keV band is 9.9 +- 2.2 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T+0.78 sec in the 15-150 keV band
is 1.1 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

Although GRB 190627A has a brief duration, it is not clear that it is a short GRB.  
The duration and relative softness of the spectrum place it intermediate between 
most short and long bursts detected by BAT.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/911609/BA/