Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 27587

GRB 200415A: Fermi GBM observation
2020-04-15T19:54:14Z (4 years ago)
Elisabetta Bissaldi at INFN,Bari <>
E. Bissaldi (Politecnico and INFN Bari), M. Briggs (UAH),
E. Burns (GSFC), O.J. Roberts (USRA) and P. Veres (UAH)
report on behalf of the Fermi GBM Team:

"At 08:48:05.56 UT on 15 April 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200415A (trigger 608633290 / 200415367),
which was also detected by Fermi-LAT (Omodei et al., GCN 27586).
The Fermi GBM Final Real-time Localization (GCN 27579)
is consistent with the LAT position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 49 degrees.

The GBM light curve shows a bright single pulse
with a duration (T90) of about 0.2 s (50-300 keV).
The time-averaged spectrum from T0-0.032 s to T0+0.160 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is 0.07 +/- 0.05 and
the cutoff energy, parameterized as Epeak, is 950 +/- 40 keV.

The event fluence (10-1000 keV) in this time interval
is (5.2 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux
measured starting from T0 in the 10-1000 keV band
is 74 +/- 2 ph/s/cm^2.

While we report the source to be a possible short GRB,
we cannot conclusively rule out a giant magnetar flare
of extragalactic origin, as reported by IPN (GCN 27585).
Periodicity is not evident in the GBM data.
Assuming a distance of 3.5 Mpc and the spectral shape reported above,
the isotropic equivalent energy in the 1 keV-10 MeV range is
(1.22 +/- 0.03)E+46 erg. Further analysis is ongoing.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:

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