GCN Circular 18067

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU),
T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-225 to T+977 sec from the recent telemetry downlink,
we report further analysis of trigger #650221 on IGR J00291+5934
(Barthelmy, et al., GCN Circ. 18061
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 7.269, 59.583 deg which is
    RA(J2000)  =   00h 29m 04.6s
    Dec(J2000) =   59d 34' 59"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.

The mask-weighted lightcurve shows a single peak about 17 seconds long on top
of a much weaker variable emission over the entire observation.

The 20-second peak was much softer than the ongoing emission.  The time-averaged
spectrum from T-225 to T+977 sec is best fit by a simple power-law model.  The
power law index of the time-averaged spectrum is 3.0 +- 0.6.  The fluence in the
15-150 keV band was (1.4 +- 0.6) x 10^-06 erg/cm^2.  The time-averaged spectrum
from T-1.6 to T+16.6 sec is also best fit by a simple power-law model.  The power
law index of the time-averaged spectrum is 5.5 +- 1.1.  The fluence during that
interval was (2.4 +- 0.5) x 10^-07 erg/cm^2.  The 1-sec peak photon flux measured
from T+20.93 sec in the 15-150 keV band was 0.7 +- 0.3 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/650221/BA/