[vsnet-grb-info 7287] AXP 1E1547.0-5408: RHESSI observations up to 400 keV

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8857
SUBJECT: AXP 1E1547.0-5408: RHESSI observations up to 400 keV
DATE:    09/01/28 01:40:47 GMT
FROM:    Eric Bellm at UCB/SSL  <ebellm at ssl.berkeley.edu>

E. Bellm, D. M. Smith, and K. Hurley on behalf of the RHESSI team report:

On January 22, 2009, RHESSI observed repeated outbursts from AXP
1E1547.0-5408 (Gronwall et al., GCN 8833).  After a single ~2 second burst
at 03:50:38 UT, a series of bursts was recorded from 05:14:03--05:26:51
UT. A second series was observed from 06:43:48--06:55:57 UT. The periods
without observed emission are attributable to SAA passages and Earth
occultation.

The brightest burst was observed at 06:48:05 UT. This burst showed an
initial spike with a peak count rate of 2.6E5 counts/s over a 10 ms
interval and emission to 400 keV.  The spike was followed by the pulsing
tail (~2 s period) reported by Mereghetti et al. (GCN 8841) using INTEGRAL
SPI-ACS.  A previous burst at 06:45:13.54 UT may have been brighter, as
its peak showed evidence of saturation.  A one minute complex of bursts
beginning at 05:17:40 UT showed emission to 250 keV.

RHESSI observed a fast spike from the SGR at 05:18:32.45 UT.  This event
had an initial peak with a background-to-peak rise time of 12 ms and FWHM
of 16 ms.  A shoulder after the initial peak extended the total duration
(T90) to 70 ms.  This spike was also observed by INTEGRAL SPI-ACS.  A
lightcurve for this burst is available at
http://ssl.berkeley.edu/ipn3/1E154/rhessi.pdf