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"26360 results found.
- EP260610a: COLIBRÍ optical upper limits
- EP260610a: Einstein Probe detection of a fast X-ray transient
- Konus-Wind detection of GRB 260604C
- GRB 260608A: Fermi GRB Observation
- GRB 260604C: AstroSat CZTI detection
- IPN triangulation of GRB 260601B / EP260601a
- GRB 260604C: SVOM/ECLAIRs refined analysis
- GRB 260608A: SVOM/ECLAIRs refined analysis
- Konus-Wind detection of GRB 260607B
- GRB 260607B: GECAM-B observation
- GRB 260604C: further SAO RAS optical observations
- GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
- GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
- GRB 260604C: SVOM/C-GFT upper limit
- GRB 260607B: AstroSat CZTI detection
- GRB 260608A: SVOM detection of a burst
- EP260605a: EP-FXT follow-up observation
- GRB 260607A: TRT optical observations
- GRB 260604C: GRANDMA further observations
- GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
- GRB 260604A: SVOM/GRM detection
- GRB 260607B: Fermi GBM Observation
- GRB 260607B: Fermi-LAT detection
- GRB 260607B: Fermi GBM Final Localization Correction
- GRB 260604C: OPD1.6m - GRANDMA observations - detection
- GRB 260604C: GECAM-B observation
- GRB 260604C: 6 GHz VLA observations
- GRB 260604C: SAO RAS optical observations
- GRB 260604C: GRANDMA observations
- GRB 260604B: SVOM/GRM detection
- GRB 260605A: Insight-HXMT/HE detection
- GRB260603A: SVOM/ECLAIRs refined analysis
- EP260605a: Einstein Probe detection of a fast X-ray transient
- EP260603a: COLIBRÍ optical upper limit
- GRB 260604A: Glowbug gamma-ray detection
- GRB 260604C: LCO optical upper limit
- EP260602d: EP-FXT follow-up observation
- EP260602c: EP-FXT follow-up observation
- GRB 260601B / EP260601a: AstroSat CZTI detection
- GRB 260527A/EP260527a: 6 GHz VLA observations
- GRB 260604C: GOTO detections of the optical afterglow
- GRB 260604C: Kilonova-Catcher optical afterglow detection
- GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260604C: Jinshan optical observations
- GRB 260604C: Fermi GBM Observation
- EP260602d: J-band upper limit with WINTER
- EP260602b: J-band upper limit with WINTER
- GRB 260604C: LAST detection of optical counterpart candidate
- SVOM GRB260604.85: Global MASTER-Net observations report
- GRB 260604C: SVOM detection of a long burst
- GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
- GRB 260603A: NOT optical observations
- GRB 260601A: CALET Gamma-Ray Burst Monitor detection
- EP260602a: EP-FXT follow-up observation
- EP260603a: Einstein Probe detection of a fast X-ray transient
- Konus-Wind detection of GRB 260601B/EP260601a
- GRB 260603A: EP-FXT follow-up observation
- EP260601a/GRB 260601B: EP-FXT follow-up observation
- EP260602b: EP-FXT follow-up observation
- GRB 260601B/EP260601a: Glowbug gamma-ray detection
- GRB 260603A: Kilonova-Catcher optical upper limit
- GRB 260603A: SVOM/VT optical observations
- EP260602a: NOT NIR J-band observations
- GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
- EP260602d: Einstein Probe detection of a fast X-ray transient
- EP260602a: SVOM/VT optical magnitudes correction
- GRB 260601A: SVOM/GRM observation of a short burst
- EP260602c: Einstein Probe detection of a fast X-ray transient
- GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
- EP260602a: COLIBRÍ optical observations
- SVOM GRB260603.23: Global MASTER-Net observations report
- GRB 260603A: SVOM detection of a burst
- EP260602b: Einstein Probe detection of a fast X-ray transient
- GRB 260601B/EP260601a: Insight-HXMT detection
- EP260530a: Xinglong optical spectroscopy of EP260530a / AT 2026nwl
- EP260602a: SVOM/VT optical candidate
- EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
- GRB 260601A: GECAM-B observation of a short burst
- GRB 260601B/EP260601a: J-band upper limit with WINTER
- EP260530a/AT 2026nwl: COLIBRÍ optical follow up
- GRB 260601B: CALET Gamma-Ray Burst Monitor detection
- GRB 260601B / EP260601a: NuSTAR detection of prompt emission
- EP260602a: Einstein Probe detection of a fast X-ray transient
- GRB 260601B/EP260601a: SVOM/VT optical observations
- GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
- GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
- EP260601a: Einstein Probe detection of an X-ray transient
- EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
- EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection
- GRB 260601A: Glowbug gamma-ray detection of a short burst
- GRB 260531B: Glowbug gamma-ray detection
- GRB 260601A: Fermi GBM Observation
- EP260530a/AT 2026nwl: COLIBRÍ optical observations
- GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
- GRB 260527A/EP260527a: Glowbug gamma-ray detection
- GRB 260531B: GECAM-B observation
- GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
- GRB 260531C: Fermi GBM Final Localization Correction
- AT 2026nuz: COLIBRÍ optical observations
- IPN triangulation of GRB 260527A / EP260527a