[vsnet-grb-info 15238] SGR 1935+2154: Swift-BAT observations of additional short soft events

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16530
SUBJECT: SGR 1935+2154: Swift-BAT observations of additional short soft events
DATE:    14/07/06 18:47:13 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings at nasa.gov>

J. R. Cummmings reports on behalf of the Swift-BAT team:

Swift-BAT has observed three additional short, soft events from SGR 1935+2154
(Stamatikos et al. GCN 16520, Lien et al. GCN 16522).  The first was at
285.8 seconds after the discovery event reported in Stamatikos et al.  The
second was at T+497.4 seconds.  The third was at T+27157 seconds (BAT
trigger # 603514; no automated response occurred since the brightness was
less than the threshold set for retriggering on the known source).

At the time of the earlier two events, Swift had slewed to the source
position, so the source was on axis.  At the time of the later event, the
source was 17% coded in BAT.

The fluences of the earlier events were about 1/3 and 1/5 of the fluence
of the discovery event and were too low to get reliable spectral data.  A
simple power-law fit of the spectrum of the later event has a photon index
of 2.8 ± 0.2.  The fluence from 15-150 keV in 0.07 seconds was
(6.1 ± 1.2) x 10^-8 ergs/cm^2.