GCN Circular 9546
Subject
GRB 090621A: Swift-BAT refined analysis
Date
2009-06-22T01:14:19Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
P.A. Curran (MSSL-UCL), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), 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 set from T-239 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090621A (trigger #355303)
(Curran, et al., GCN Circ. 9540). The BAT ground-calculated position is
RA, Dec = 10.987, 61.938 deg, which is
RA(J2000) = 00h 43m 56.8s
Dec(J2000) = +61d 56' 17.6"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 77%.
The mask-weighted light curve shows two small precursor peaks starting
at ~T-30 sec, peaking at ~T-20 and T+10 sec, and returning to background
at ~T+100 sec. Then the mmain emission starts at ~T+210 sec, peaks at ~T+240
and T+265 sec, and returns to background around T+350 sec.
T90 is not possible because of a lack of the complete set of event by event
data set for this burst. This also prevents giving spectral results.