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"24353 results found.
- GRB 260506B: cubesat Avion detection
- GRB 260616C: GECAM-B observation of a burst
- GRB 260618A: Fermi GBM Final Real-time Localization
- GRB 260617A: Fermi GBM Detection
- GRB 260616A: Fermi GBM Observation
- GRB 260617A: Fermi GBM Final Real-time Localization (Duplicate Submission)
- GRB 260617A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 260616B/EP260616a
- Konus-Wind detection of GRB 260616A
- GRB 260616B: CALET Gamma-Ray Burst Monitor detection
- EP260616a/GRB260616B: COLIBRÍ optical upper limit
- GRB 260616A: GECAM-B observation
- GRB 260429A: cubesat Avion detection
- GRB 260616A: Fermi-LAT detection
- 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
- GRB 260616B: BALROG localization (Fermi Trigger 803286321 / GRB 260616295)
- The EP-WXT trigger 01709269893 is likely a flaring star
- GRB 260616A: BALROG localization (Fermi Trigger 803272919 / GRB 260616140)
- GRB 260616A: Fermi GBM Final Real-time Localization
- GRB 260614B: SVOM/ECLAIRs refined analysis
- GRB 260614B: GECAM-B observation
- GRB 260610B: SVOM/GRM observation
- GRB 260614B: SVOM/VT optical afterglow confirmation
- GRB 260614B: Fermi GBM Observation
- GRB 260614B: SVOM/VT optical candidate from VHF data
- GRB 260614B: SVOM detection of a burst
- GRB 260614B: Fermi GBM Final Real-time Localization
- GRB 260611B: SVOM/GRM detection
- GRB 260614A: Fermi GBM Final Localization
- The EP-WXT trigger 01709269488 is likely a flaring star
- GRB 260610B: Fermi GBM Observation
- EP260605a: COLIBRÍ optical upper limits
- EP260610b: Liverpool Telescope optical upper limits
- IceCube-260610A: No candidates from the Zwicky Transient Facility
- IceCube-260610A: EP-FXT follow-up observation
- GRB 260611B: CALET Gamma-Ray Burst Monitor detection
- GRB 260610B / AT2026owq: SVOM/VT optical observations
- GRB 260611B: Fermi GBM Final Real-time Localization
- EP260610b: GTC likely spectroscopic redshift z = 1.10
- 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 / AT2026owq: Early ATLAS observations
- EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
- GRB 260611A: Fermi GBM Final Real-time Localization
- GRB 260610B: GOTO optical counterpart candidate
- GRB 260610B: Fermi GBM Final Localization
- EP260610b: SVOM/VT optical confirmation with blue color
- IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260515A: SOAR optical observations
- EP260610a: SVOM/VT optical upper limits
- Konus-Wind detection of GRB 260601A
- IPN triangulation of GRB 260601A (short/hard)
- GRB 260610A: Fermi GBM Final Real-time Localization (duplicate submission)
- GRB 260610A: Fermi GBM Final Real-time Localization
- GRB 260609A: Fermi GBM Final Localization
- Konus-Wind detection of GRB 260604C
- GRB 260608A: Fermi GRB Observation
- 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 260608C: Fermi GBM Final Real-time Localization (duplicate submission)
- GRB 260608C: Fermi GBM Final Real-time Localization
- GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
- GRB 260608B: Fermi GBM Final Localization
- GRB 260604C: SVOM/C-GFT upper limit
- GRB 260608A: SVOM detection of a burst
- GRB 260608A: Fermi GBM Final Real-time Localization (duplicate submission)
- GRB 260608A: Fermi GBM Final Real-time Localization
- 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 260607A: Fermi GBM Final Real-time Localization (duplicate submission)
- GRB 260607A: Fermi GBM Final Real-time Localization
- GRB 260604C: GECAM-B observation
- GRB 260604B: SVOM/GRM detection
- GRB260603A: SVOM/ECLAIRs refined analysis
- GRB 260604C: LCO optical upper limit
- The EP-WXT trigger 01709267001 is likely a flaring star
- EP260602d: EP-FXT follow-up observation
- EP260602c: EP-FXT follow-up observation
- GRB 260604C: GOTO detections of the optical afterglow
- The EP-WXT trigger 01709266798 is likely a flaring star
- GRB 260604C: Fermi GBM Observation
- EP260602d: J-band upper limit with WINTER
- Fermi GRB 260604C: Global MASTER-Net observations report
- Fermi GRB 260604C: Global MASTER-Net observations report
- SVOM GRB260604.85: Global MASTER-Net observations report
- GRB 260604C: SVOM detection of a long burst
- GRB 260604C: Fermi GBM Final Real-time Localization
- GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
- GRB 260604B: Fermi GBM Final Real-time Localization