GCN Circular 13280
Subject
Fermi/GBM detection of a burst from the magnetar 1E 2259+5
Date
2012-05-04T17:51:15Z (13 years ago)
From
Chryssa Kouveliotou at MSFC <chryssa.kouveliotou@nasa.gov>
S. Foley (UCD), C. Kouveliotou (NASA/MSFC), Y. Kaneko (Sabanci
University) and Andrew Collazzi (NASA/ORAU) report on behalf
of the Fermi/GBM Team:
�
At 08:17:43.71 UT on 21 April 2012, the Fermi Gamma-Ray Burst
Monitor triggered on a short, soft event very similar to an SGR
burst (trigger 356689065/120421346).
�
The on-ground calculated location is RA = 357.0, DEC = 40.0(J2000
degrees, equivalent to 23h 48 m, 40d 00'), with an uncertainty of
12 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be
2 to 3 degrees). This location is consistent with 1E 2259+586, albeit
with a large error radius.
�
The event had a duration of ~ 40 ms (20-100 keV) and was equally
well fit either with an OTTB function of kT=85+-17 keV or with a
single blackbody spectrum of kT=17+-1 keV. These results are
preliminary.
�
Untriggered event searches between April 18-24, 2012 (+- 3 days
around the trigger time) did not reveal any additional bursts at
the same significance level from the same direction.
�
Given the recent report by Archibald et al. (ATel 4080, 2012) about
the detection of a flux increase of 1E 2259+586 with Swift, we
suggest that this magnetar source was indeed the origin of the
GBM burst.
�
Further observations of the source in multiple wavelengths are
encouraged.