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 9123

GRB 090410: Swift-BAT refined analysis
2009-04-10T23:59:04Z (15 years ago)
Scott Barthelmy at NASA/GSFC <>
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), C.B. Markwardt (GSFC/UMD), D.M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data sets from T-240 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090410 (trigger #348929)
(Grupe, et al., GCN Circ. 9122).  The BAT ground-calculated position is
RA, Dec = 334.956, 15.419 deg, which is 
   RA(J2000)  =  22h 19m 49.4s 
   Dec(J2000) = +15d 25' 08.6" 
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows two main peaks with some precursor activity.
The precursor activity starts at ~T-55 sec.  And because the target location
only came into the BAT FOV at T-110 sec, there may have been even earlier activity.
The first main peak started at ~T-10 sec, peaked at ~T+7 sec, and ended 
around T+45 sec.  The second main peak started at ~T+80 sec, peaked at ~T+120 sec,
and returned to baseline T+170 sec.  The burst location left the BAT FOV
at ~T+390 sec.  T90 (15-350 keV) is 165 +- 8 sec (estimated error
including systematics).
The time-averaged spectrum from T-49.2 to T+139.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.19 +- 0.05.  The fluence in the 15-150 keV band is 5.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+8.90 sec in the 15-150 keV band
is 1.9 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
The results of the batgrbproduct analysis are available at
Looking for U.S. government information and services? Visit