GCN Circular 14163
Subject
GRB 130131A: Swift-BAT refined analysis
Date
2013-01-31T23:03:50Z (11 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
D. Grupe (PSU), H. A. Krimm (GSFC/USRA), A. Lien (GSFC/ORAU),
C. B. Markwardt (GSFC), T. Sakamoto (AGU), G. Sato (ISAS),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+903 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130131A (trigger #547407)
(Grupe, et al., GCN Circ. 14156). The BAT ground-calculated position is
RA, Dec = 171.091, 48.064 deg which is
RA(J2000) = 11h 24m 21.9s
Dec(J2000) = +48d 03' 51.0"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 97%.
The mask-weighted light curve shows two separated peaks: (1) starting at ~T-5 sec,
peaking at ~T+1 sec, and ending at ~T+15 sec, and (2) T+35, T+47, and ~T+65 sec.
T90 (15-350 keV) is 51.6 +- 2.4 sec (estimated error including systematics).
The time-averaged spectrum from T-0.95 to T+52.15 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.12 +- 0.32. The fluence in the 15-150 keV band is 3.1 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.04 sec in the 15-150 keV band
is 0.7 +- 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/547407/BA/