TITLE:   GCN CIRCULAR
NUMBER:  46126
SUBJECT: GRB 261101B: Fermi GBM Final Real-time Localization
DATE:    26/11/01 15:48:21 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

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

At 15:37:52 UT on 1 Nov 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261101B (trigger 815240277.50196 / 261101651).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 321.6, Dec = 14.6 (J2000 degrees, equivalent to J2000 21h 26m, 14d 35'), with a statistical uncertainty of 2.0 degrees.

The angle from the Fermi LAT boresight is 89.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261101651/quicklook/glg_skymap_all_bn261101651.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261101651/quicklook/glg_healpix_all_bn261101651.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261101651/quicklook/glg_lc_medres34_bn261101651.gif