[vsnet-grb-info 2523] Refined analysis of the Swift-BAT detection of the RS CVn star II Peg

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4360
SUBJECT: Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
DATE:    05/12/16 19:15:30 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

L. Barbier (GSFC), S. Barthelmy (GSFC),  J. Cummings (GSFC/NRC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), T. McMahon (Langston U.)
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), J. Tueller (GSFC),
N. White (GSFC)   
on behalf of the Swift-BAT team:

The BAT trigger (172969) reported in GCN 4357 (Holland et al)
is definitely not due to a GRB.  It is due to a hard x-ray emission
from the RS CVn star II Peg.

Using the full data set from recent Malindi downlinks covering
T-300 sec to T+300 sec,  we see a remarkably smooth lightcurve
from this source.  The emission slowly increases from 0.02 cnt/cm2-sec
to 0.04 cnt/cm2-sec over the 10 minute interval.

The refined BAT location is RA,Dec = 358.799,+28.620 +/- 2.5 arcmin
{23h 55m 11.6s,28d 37' 11.6"} (J2000).  This is 1.7 arcmin from the 
catalog position of II Peg.

Using a simple power law, the index is 2.98 +/- 0.42.