[vsnet-grb-info 25450] GRB 200412A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27550
SUBJECT: GRB 200412A: Fermi GBM detection
DATE:    20/04/12 14:04:54 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007 at uah.edu>

B. Mailyan (Institute for Basic Science, South Korea) and R. Hamburg (UAH)
report on behalf of the Fermi GBM Team:

"At 06:57:11.95 UT on 12 April 2020, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 200412A (trigger 608367436 / 200412290).
This trigger was originally misclassified as a particle event by the flight
software.

The on-ground calculated location, using the Fermi GBM trigger data, is RA
= 140.01, Dec = -41.67 (J2000 degrees, equivalent to J2000 09h 20m, -41d
40’), with a statistical uncertainty of 1.4 degrees.

The angle from the Fermi LAT boresight is 108 degrees.

The GBM light curve shows multiple short peaks with a duration (T90) of
about 12.6 s (50-300 keV).

The time-averaged spectrum from T0 s to T0+14.0 s is best fit by a Band
function with Epeak = 255 +/- 8.5 keV, alpha = -0.64 +/- 0.03, and beta =
-2.66 +/- 0.14.

The event fluence (10-1000 keV) in this time interval is (3.1 +/- 0.04)E-05
erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.2 s in the
10-1000 keV band is 34.3 +/- 0.6 ph/s/cm^2.

The spectral analysis results presented above are preliminary; final
results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support
Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"