Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 27659

Fermi GBM observation of a bright flare from magnetar SGR 1935+2154
2020-04-28T02:28:30Z (4 years ago)
Cori Fletcher at USRA <>
C. Fletcher (USRA) reports on behalf of the Fermi GBM Team:

"At 18:26:20.16 UT on 27 April 2020, the Fermi Gamma-Ray Burst
Monitor triggered on a bright, SGR-like burst from the direction
of the magnetar SGR 1935+2154 (trigger 609704785/ 200427768),
which was also detected by the Swift/BAT (Barthelmy et al. 2020, GCN 27657).

The burst has a duration (T90) of ~2 seconds in the energy range 10-200 keV.

It is well-fit by a power law function with an exponential
high-energy cutoff. The power law index is 0.02 +/- 0.68 and
the cutoff energy, parameterized as Epeak, is 27.2 +/- 2.5 keV.

The event fluence (10-200 keV) from T0-1.024 to T0+1.024 is (2.0 +/- 0.2)E-7 erg/cm^2.
The average photon flux in the 10-200 keV band during this period is 2.5 +/- 0.2

Fermi GBM also subsequently triggered on multiple bursts from SGR 1935+2154 on
27 April 2020 with a fraction of these being misclassified as GRBs.

The spectral analysis results presented above are preliminary.

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
Looking for U.S. government information and services? Visit