TITLE: GCN CIRCULAR NUMBER: 40462 SUBJECT: GRB 250515A: Fermi GBM Final Localization DATE: 25/05/15 21:34:47 GMT FROM: R. Hamburg at CNRS/IJCLab rachel.k.hamburg@gmail.com

The Fermi GBM team reports the detection of a likely SHORT GRB

"At 20:46:21.91 UT on 15 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250515A (trigger 769034786/250515866).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 154.35, Dec = 23.19 (J2000 degrees, equivalent to J2000 10h 17m, +23d 11'), with a statistical uncertainty of 7.76 degrees.

The angle from the Fermi LAT boresight is 69 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250515866/q...

The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250515866/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250515866/q..."

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