Back

GCN Circular 22877

Subject

GRB 180630A: Swift-BAT refined analysis

Date

2018-07-01T12:30:12Z (6 years ago)

From

Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC), 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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180630A (trigger #845443)
(D'Avanzo, et al., GCN Circ. 22872Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 48.885, -87.476 deg which is
    RA(J2000)  =  03h 15m 32.5s
    Dec(J2000) = -87d 28' 33.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 59%.
  
The mask-weighted light curve shows a double-peaked structure.  The first pulse
starts at T0, peaks at T+4 sec and ends at T+15 sec.  The second weak pulse
starts at T+15 sec and ends at T+30 sec.  T90 (15-350 keV) is 18.85 +- 6.45 sec
(estimated error including systematics).
  
The time-averaged spectrum from T-0.36 to T+30.02 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.07 +- 0.10.  The fluence in the 15-150 keV band is 1.8 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.65 sec in the 15-150 keV band
is 6.6 +- 0.4 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/845443/BA/