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GCN Circular 8835

AXP 1E1547.0-5408: Fermi GBM observations
2009-01-22T08:39:21Z (15 years ago)
Valerie Connaughton at MSFC <>
Valerie Connaughton (UAH) and Michael Briggs (UAH)
report on behalf of the Fermi GBM Team:

"At 00:53:52.17 UT on 22 Jan 2009, the Fermi Gamma-Ray Burst Monitor
triggered on AXP 1E1547.0-5408 (trigger 254278434 / 090122037).

Since then, GBM has seen 18 triggers from this source including one
trigger also detected by the Swift-BAT (Palmer et al. 2009, GCN 8833).

The trigger rate is consistent with constant source activity in the
form of short and often very bright pulses occurring within an interval
of a few seconds to about 150s between pulses.   We estimate the source
activity is constant because the time between triggers is between 600s
and 740s outside of SAA passages and periods during which the source is
occulted by the Earth.   The minimum possible trigger spacing for
GBM is 596 seconds.  

Because of the high data rate these triggers have caused, it is not
yet possible to perform spectral analysis of any of these events.  We
estimate from our real-time data, however, that the source is visible at
least up to 100 keV and is not visible above 300 keV."
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