GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"26500 results found.
- IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260619A: TRT optical counterpart confirmation
- GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
- Fermi-LAT Gamma-ray Observations of IceCube-260610A
- GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- Konus-Wind detection of GRB 260617A
- GRB 260616B: AstroSat CZTI detection
- GRB 260616A: AstroSat CZTI detection
- GRB 260616A: SVOM/GRM observation
- EP260618a: OHP/T193 optical observations
- GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
- GRB 260619A: Kilonova-Catcher optical upper limit
- EP260618a: EP-FXT follow-up observation
- EP260618a: LCO optical counterpart confirmation
- EP260618a: COLIBRÍ optical counterpart candidate
- GRB 260619A: SVOM possible detection of a faint burst
- IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
- EP260618a: EP-WXT detection of an X-ray transient
- GRB 260610B: AbAO optical observations
- EP260616a/GRB 260616B: EP-FXT follow-up observation
- GRB 260506B: cubesat Avion detection
- GRB 260616C: GECAM-B observation of a burst
- GRB 260617A: Fermi GBM Detection
- GRB 260616A: Fermi GBM Observation
- Konus-Wind detection of GRB 260616B/EP260616a
- EP260616a/GRB260616B: COLIBRÍ optical upper limit
- GRB 260616A: GECAM-B observation
- GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
- GRB 260429A: cubesat Avion detection
- GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
- EP260616a: EP-WXT detection of a fast X-ray transient
- The EP-WXT trigger 01709270148 is likely a flaring star
- GRB 260616B: Fermi GBM Detection
- The EP-WXT trigger 01709269893 is likely a flaring star
- GRB 260614B: SVOM/ECLAIRs refined analysis
- GRB 260610B: Terskol optical observations
- GRB 260614B: GECAM-B observation
- GRB 260610B: SVOM/GRM observation
- GRB 260614B: Fermi GBM Observation
- GRB 260614B: SVOM/VT optical candidate from VHF data
- GRB 260614B: SVOM detection of a burst
- GRB 260611B: SVOM/GRM detection
- The EP-WXT trigger 01709269488 is likely a flaring star
- GRB 260603C: AstroSat CZTI detection
- GRB 260610B: further Liverpool Telescope optical observations
- GRB 260610B: Fermi GBM Observation
- GRB 260610B / AT2026owq: GRANDMA optical observations
- GRB 260610B / AT2026owq: further SAO RAS optical observations
- EP260605a: COLIBRÍ optical upper limits
- GRB 260610b: Liverpool Telescope optical observations
- EP260610b: Liverpool Telescope optical upper limits
- IceCube-260610A: EP-FXT follow-up observation
- The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
- GRB 260610B / AT2026owq: SAO RAS optical observations
- The EP-WXT trigger 01709269176 is likely a flaring star
- EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
- GRB 260610B / AT 2026owq: COLIBRÍ optical observations
- GRB 260610B: TRT optical observation
- EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
- EP260610b: COLIBRÍ optical observations
- GRB 260610B: DDOTI optical observations
- EP260610b: MAO/AZT-22 optical observations
- EP260610b: NOT optical observation
- EP260610b: SVOM/VT optical confirmation with blue color
- GRB 260515A: SOAR optical observations
- EP260610a: SVOM/VT optical upper limits
- EP260610b: Einstein Probe detection of an X-ray transient
- Konus-Wind detection of GRB 260601A
- EP260610a: COLIBRÍ optical upper limits
- EP260610a: Einstein Probe detection of a fast X-ray transient
- GRB 260608A: Fermi GRB Observation
- GRB 260604C: SVOM/ECLAIRs refined analysis
- GRB 260608A: SVOM/ECLAIRs refined analysis
- GRB 260607B: GECAM-B observation
- GRB 260604C: further SAO RAS optical observations
- GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
- 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 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
- GRB 260604A: SVOM/GRM detection
- GRB 260604C: Mondy optical observations: evidence of a possible brightening
- GRB 260607B: Fermi GBM Observation
- GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
- 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 260604B: SVOM/GRM 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
- The EP-WXT trigger 01709267001 is likely a flaring star
- EP260602d: EP-FXT follow-up observation