GCN Circular 3871
Subject
GRB 050824: BAT refined analysis of a soft weak burst
Date
2005-08-25T04:40:32Z (19 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
H. Krimm (GSFC/USRA), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/NRC), K. Gendreau (GSFC), D. Hullinger (GSFC/UMD),
E. Fenimore (LANL), N. Gehrels (GSFC), C. Markwardt (GSFC/UMD),
P. Meszaros (PSU), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the full data set from the recent telemetry downlink, we
report further analysis of Swift-BAT GRB 050824 (trigger #151905)
(Campana, et al., GCN 3866). The ground-analysis position is
RA,Dec 12.256 +22.618 (J2000) with an uncertainty of 3 arcmin
(radius, 90%, stat+sys). This is 1.9 arcmin from the onboard
position and 1.4 arcmin from the optical candidate reported by
Gorosabel et al. in GCN Circ. 3865.
The light curve shows a single peak with slow rise and slow decay.
T90 is 25 +- 5 seconds. Fitting a simple power law over the
interval from T+38 to T+64 sec, the photon index is 2.7 +/- 0.4
with a fluence of 2.3 +/- 0.5 x 10^-7 erg/cm^2 in the 15-150 keV
band (90% c.l). The peak flux in a 1-second wide window starting
at T+53 sec is 0.5 +/- 0.2 ph/cm^2/sec (15-150 keV).
The original GCN Notices were delayed in transmission to the ground
by 500 sec due to the burst happening during a telemetry downlink
session when the TDRSS real-time messages are held in a buffer until
the end of the downlink.