GRB 250416A
GCN Circular 40149
Subject
GRB 250416A: Fermi GBM Final Real-time Localization
Date
2025-04-16T14:17:00Z (a month ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 14:06:21 UT on 16 Apr 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250416A (trigger 766505186.401302 / 250416588).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 323.8, Dec = 70.5 (J2000 degrees, equivalent to J2000 21h 35m, 70d 30'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 111.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416588/quicklook/glg_skymap_all_bn250416588.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416588/quicklook/glg_healpix_all_bn250416588.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416588/quicklook/glg_lc_medres34_bn250416588.gif
GCN Circular 40155
Subject
Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
Date
2025-04-17T04:59:28Z (a month ago)
From
Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
Web form
L. Scotton (UAH) and O. Mukherjee (USRA) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"The Fermi Gamma-ray Burst Monitor (GBM) trigger 766505186/250416588 at 14:06:21.40 UT
on 16 April 2025, tentatively classified as a GRB, is in fact not due
to a GRB. This trigger is likely due to distant particles."