General information
GRB 251118A triggered Fermi/GBM on 2025-11-18 20:31:30 UT and was also detected by multiple gamma-ray instruments including Fermi/LAT. Swift follow-up identified a likely X-ray/UV-optical afterglow consistent with the high-energy localizations.
Wavelength coverage
- Gamma-ray: Fermi/GBM; Fermi/LAT; Konus-Wind; GECAM-B; Glowbug (ISS); NuSTAR shields (SINGS); TERI (ISS).
- X-ray: Swift/XRT detected a likely uncatalogued afterglow and provided an enhanced position.
- UV/Optical: Swift/UVOT detected a fading counterpart; SAO RAS Zeiss-1000 detected an optical transient in Rc; VLT/MUSE detected continuum and spectral features.
- Other: No radio, IR, sub-mm/mm, TeV, neutrino, or GW observations are mentioned in the provided facts.
Lightcurve and spectrum
Redshift
z = 1.217 from VLT/UT4 MUSE absorption features (Fe II, Mg II, Mg I, Ca II); [O II] 3726,3729 emission detected at z = 1.218.
What’s special vs typical
GCN 44680: GRB 251118A: TERI Gamma-ray detection
2026-05-21T14:05:27.946Z | rev 0
GCN 43056: EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
2025-12-09T17:24:40.380Z | rev 0
GCN 43013: Konus-Wind detection of GRB 251118A
2025-12-06T16:38:47.110Z | rev 0
2025-11-20T22:23:37.128Z | rev 2
GCN 42785: EP251118a / GRB 251118C: SAO RAS optical observations
2025-11-20T21:15:01.193Z | rev 0
GCN 42784: GRB 251118A: Glowbug gamma-ray detection
2025-11-20T20:44:33.183Z | rev 0
GCN 42783: GRB 251118A: Fermi GBM Observation
2025-11-20T19:37:15.327Z | rev 0
GCN 42782: GRB 251118A: Swift-XRT afterglow detection
2025-11-20T13:53:24.677Z | rev 0
2025-11-20T08:32:34.631Z | rev 0
GCN 42776: EP251118a / GRB 251118C: SVOM/VT optical observation
2025-11-20T06:52:54.176Z | rev 0
GCN 42774: GRB 251118A: NuSTAR detection of bright prompt emission
2025-11-20T00:26:27.169Z | rev 0
GCN 42773: EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
2025-11-19T23:38:46.501Z | rev 0
GCN 42767: EP251118A / GRB 251118C : MASTER optical counterpart observations
2025-11-19T17:40:22.986Z | rev 0
2025-11-19T05:39:12.824Z | rev 0
GCN 42750: GRB 251118A: Swift ToO observations
2025-11-19T05:10:33.320Z | rev 0
GCN 42745: GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
2025-11-18T20:57:48.593Z | rev 0
GCN 42743: GRB 251118A: Fermi GBM Final Real-time Localization
2025-11-18T20:42:00.447Z | rev 0