TITLE:   GCN CIRCULAR
NUMBER:  8837
SUBJECT: AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase 
DATE:    09/01/22 16:22:32 GMT
FROM:    Volodymyr Savchenko at ISDC,U of Geneve  <volodymyr.savchenko@unige.ch>

V. Savchenko, V. Beckmann, A. Neronov (ISDC), S.
Mereghetti  (INAF/IASF-Milano), A. von Kienlin (MPE), M. Beck (ISDC), J.
Borkowski (CAMK/Torun), D. Gotz  (CEA/Saclay) report on behalf of the
INTEGRAL SPI-ACS GRB team:

The SPI Anti-Coincidence System (ACS) on-board INTEGRAL has detected
burst activity most likely arising from the AXP 1E1547.0-5408, as
reported based on Swift/BAT (GCN 8834, 8833) and Fermi GBM data (GCN
8835).

 From 2009-01-22T00:42:05 until 10:49:56 UT, 167 short (from 50ms to
  8s) intense bursts were detected with significance from 5 to 160 sigma
(1e4 - 2e6 counts/s peak count rate).

The SPI-ACS light curves of triggered events are available (both as
images and data files)
at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi

The light curves, binned at 50 ms, are derived from 91 independent
detectors with different lower energy thresholds (mainly between 50 keV
and 150 keV) and an upper threshold at about 100 MeV. The ACS response
varies as a function of the GRB incident angle. For these reasons we
caution that the count rates cannot be easily translated into physical
flux units.