GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"24454 results found.
- LIGO/Virgo/KAGRA S250118az: Updated Sky localization
- LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
- GRB 250206A: EIRSAT-1 GMOD Detection
- LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
- GRB 250206A: Fermi-LAT detection
- GRB 250207B: Swift-XRT observations
- LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
- IceCube-250203A: No transient candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS
- LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
- GRB 250208A: Fermi GBM Final Real-time Localization
- EP250207a: EP-WXT detection and XRT follow-up observation
- LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
- GRB 250207A: Swift-XRT refined Analysis
- LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
- CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
- LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
- EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
- GRB 250129A: ABObservatory SLOAN r’ afterglow detection
- GRB 250207A: REM IR afterglow detection
- LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
- LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
- Konus-Wind detection of GRB 250204B
- IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 250207A: REM optical afterglow detection
- LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
- LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
- LIGO/Virgo/KAGRA S250206dm: SOAR galaxy targeted observations
- LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
- LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
- LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
- GRB 250207A: Fermi GBM Final Real-time Localization
- Fermi-LAT Gamma-ray Observations of IceCube-250203A
- LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
- LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
- GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
- GRB 250206A: Fermi GBM Final Real-time Localization
- GRB 250205A: Fermi GBM Observation
- GRB 250205A: REM NIR upper limit
- LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
- EP250205a/GRB 250205A: correction to the source localization
- EP250205a/GRB 250205A: Einstein Probe observation
- GRB 250127C: SVOM/GRM observation of a burst
- GRB250205A: SVOM/VT optical afterglow detection
- GRB 250205A: GOTO optical upper limits
- LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
- GRB 250205A: SVOM detection of a burst
- LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
- Konus-Wind detection of GRB 250201A
- IPN triangulation of GRB 250201A
- LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
- Konus-Wind detection of GRB 250202B
- LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
- GRB 250129A: Swift-BAT refined analysis
- EP 250108A: Upper limits from Fermi-GBM Observations
- IPN triangulation of GRB 250204B (short/hard)
- IPN triangulation of GRB 250202B
- LIGO/Virgo/KAGRA S250204ax: Updated Sky localization
- GRB 250204B: Fermi GBM Final Localization
- GRB 250129A: LCO late afterglow detection
- GRB 250204A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
- GRB 250202B: NuSTAR detection of the prompt emission
- GRB 250202C: GRBAlpha detection
- GRB 250202B: Fermi GBM Detection
- IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 250129a: Liverpool Telescope optical follow-up
- GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
- LIGO/Virgo/KAGRA S250202cu: Updated Sky localization
- GRB 250202C: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
- GRB 250129A: SVOM/C-GFT optical observations
- The EP-WXT trigger 01709131153 is not a real source
- LIGO/Virgo/KAGRA S250202ad: Retraction of GW compact binary merger candidate
- GRB 250202B: Fermi GBM Final Real-time Localization
- Swift GRB250129A: MASTER 4 days observations report
- GRB 250202A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 250129A
- GRB 250129A: 1.3m DFOT Optical observations
- GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
- GRB 250201A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
- GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
- EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
- GRB 250129A: iTelescope optical observation
- GRB 250129A: NOT optical observations of continuining activity
- GRB 250129A: GRANDMA/TAROT optical afterglow detection
- GRB 250128B: VLA radio upper limit
- Ep250125A: 1.3m DFOT optical upper limit
- GRB 250128B: Gemini-North optical extended source detection