Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 18256

GRB 150907B: Swift-BAT refined analysis
2015-09-08T12:27:43Z (9 years ago)
Scott Barthelmy at NASA/GSFC <>
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. G. R. Roegiers (PSU), 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 downlinks,
we report further analysis of BAT GRB 150907B (trigger #654803)
(Roegiers, et al., GCN Circ. 18249).  The BAT ground-calculated position is
RA, Dec = 255.265, -63.798 deg, which is 
   RA(J2000)  =  17h 01m 03.5s 
   Dec(J2000) = -63d 47' 51.6" 
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
The mask-weighted light curve shows a Fred-like starting at ~T-1 sec,
peaking at ~T+1 sec, and ending around T+100 sec.
T90 (15-350 keV) is 62.0 +- 11.1 sec (estimated error including systematics).
The time-averaged spectrum from T-1.48 to T+64.53 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.17 +- 1.03, 
and Epeak of 67.4 +- 29.7 keV (chi squared 53.2 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+0.59 sec in the 15-150 keV band is
1.0 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.47 +- 0.18 (chi squared 59.8 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
The results of the batgrbproduct analysis are available at
Looking for U.S. government information and services? Visit