[vsnet-grb-info 16228] Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17509
SUBJECT: Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)
DATE:    15/02/28 18:00:56 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT trigger #632888 on 4U 0142+61
(Barthelmy, et al., GCN Circ. 17507).  The BAT ground-calculated position is
RA, Dec = 26.603, 61.746 deg, which is 
   RA(J2000)  =  01h 46m 24.8s 
   Dec(J2000) = +61d 44' 47.4" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 39%.
 
The mask-weighted light curve shows multiple spikes from the source.
The event-by-event data starts at T-240 sec. The first emission is at ~T-9 sec 
and may be several unresolved spikes or a single outburst with a duration of ~1 sec.
Then come 4 splikes (durations less than ~50 msec), then a bright spike at ~T+0 sec,
then spikes at T+{10, 15, 65, 72, and 247} sec, all with durations < 75 msec.
Then the source goes out of the BAT FOV at ~T+430 sec.
T90 (15-350 keV) is 187 +- 114 sec (estimated error including systematics).
 
The time-averaged spectrum from T-9.08 to T+273.78 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.01 +- 0.29.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+9.24 sec in the 15-150 keV band
is 2.1 +- 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/632888/BA/