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"18324 results found.
- GRB 260705C: AstroSat CZTI detection
- GRB 260706A : GRANDMA Upper limits
- GRB 260708A: Kilonova-Catcher optical afterglow detection
- IceCube-260708A: One candidate from the Zwicky Transient Facility
- GRB 260709A: Fermi GBM Final Real-time Localization
- GRB 260705B: SVOM/GRM observation
- GRB 260706A: Further EP-FXT follow-up observation
- EP260707a (by EP-FXT): NOT optical upper limit
- EP260707a is not a real source
- EP260707a: LCOGT Optical Upper Limit
- EP260707a: TRT optical upper limit
- EP260707a: Einstein Probe detection of an X-ray transient
- GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
- GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- GRB 260706A: REM optical/NIR observations
- GRB 260706A: LCO optical upper limit
- GRB 260706A: EP-FXT follow-up observation
- The EP-WXT trigger 01709274151 is likely a flaring star
- The EP-WXT trigger 01709274141 is likely a flaring star
- The EP-WXT trigger 01709274014 is likely a flaring star
- GRB 260705A: LCO optical upper limits
- GRB 260704A: NOT optical upper limits
- GRB 260704A: EP-FXT follow-up observation
- GRB 260629A: SVOM/GRM observation of a short burst
- EP260703a: EP-FXT follow-up observation
- GRB 260704A: SVOM detection of a possible GRB
- EP260703a: EP-WXT detection of a fast X-ray transient
- EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
- GRB 260610B: VLA detection
- Fermi-LAT Gamma-ray Observations of IceCube-260622A
- EP260628a: EP-FXT follow-up observation
- EP260628a: EP-WXT detection of a fast X-ray transient
- The EP-WXT trigger 01709272671 is likely a flaring star
- EP260626a: further Liverpool Telescope optical upper limits
- EP260626a: EP-FXT follow-up observation
- EP260626a: COLIBRÍ optical upper limit
- EP260626a: Liverpool Telescope upper limits
- EP260626a: EP-WXT detection of a fast X-ray transient
- EP260623a: TNG NIR afterglow detection
- EP260623a: Liverpool Telescope optical observations
- EP260623a:refined analysis of the EP-WXT and EP-FXT observation
- EP260623a: WINTER J-band observations
- EP260623a: Optical follow-up observations with Kinder
- EP260623a: SVOM/VT optical observations
- EP260623a: TRT optical observations
- EP260623a: REM optical/NIR afterglow detection
- EP 260623a: COLIBRÍ optical observations
- EP260623a: Las Cumbres discovery of the optical counterpart
- EP260623a: Einstein Probe detection of an X-ray transient
- GRB 260614B: EP-FXT follow-up observation
- EP260618a: Liverpool Telescope optical observations
- GRB 260618B: LCO optical observations
- The EP-WXT trigger 01709271197 is likely a flaring star
- EP260618a: JinShan optical observations
- GRB 260616B/EP260616a: SVOM/GRM detection of a burst
- 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
- 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
- EP260618a: EP-WXT detection of an X-ray transient
- GRB 260610B: AbAO optical observations
- EP260616a/GRB 260616B: EP-FXT follow-up observation
- GRB 260616B: CALET Gamma-Ray Burst Monitor detection
- EP260616a/GRB260616B: COLIBRÍ optical upper limit
- GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
- 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
- The EP-WXT trigger 01709269893 is likely a flaring star
- GRB 260614B: SVOM/ECLAIRs refined analysis
- GRB 260610B: Terskol optical observations
- GRB 260610B: SVOM/GRM 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 260610B: further Liverpool Telescope optical observations
- 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
- 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