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"32544 results found.
- GRB 260710A: AstroSat CZTI detection
- GRB 260709A: AstroSat CZTI detection
- GRB 260714B: AstroSat CZTI detection
- GRB 260714B: Fermi-LAT detection
- IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
- GRB 260706A: ATCA detection of possible radio counterpart
- GRB 260705A: ATCA radio observations
- GRB 260619A: SVOM/VT continuous optical observations
- GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
- GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
- EP260623a: KAIT optical observations
- EP260711a: EP-FXT follow-up observation
- GRB 260708A: GRANDMA Optical Observations
- Fermi-LAT Gamma-ray Observations of IceCube-260712A
- Fermi-LAT Gamma-ray Observations of IceCube-260708A
- GRB 260710A: Insight-HXMT/HE detection
- Fermi-LAT Gamma-ray Observations of IceCube-260704A
- IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260708A: LCO optical observations
- GRB 260710A: Fermi GBM Detection
- GRB 260709A: SVOM/GRM detection
- GRB 260709A: GECAM-B observation
- IceCube-260708A: Observations with the Vera C. Rubin Observatory
- EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
- GRB 260705C: AstroSat CZTI detection
- GRB 260708A: Glowbug gamma-ray detection
- GRB 260704A: SVOM/ECLAIRs refined analysis
- GRB 260706A : GRANDMA Upper limits
- GRB 260708A: Kilonova-Catcher optical afterglow detection
- GRB 260708A: GECAM-B observation of a burst
- IceCube-260708A: One candidate from the Zwicky Transient Facility
- GRB 260708A: Fermi-GBM observation
- Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
- IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260708A: Fermi-LAT detection
- GRB 260705B: SVOM/GRM observation
- GRB 260706A: Further EP-FXT follow-up observation
- GRB 260706A: SVOM/VT optical upper limits
- EP260707a (by EP-FXT): NOT optical upper limit
- EP260707a is not a real source
- EP260707a: LCOGT Optical Upper Limit
- EP260707a: TRT optical upper limit
- GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
- GRB 260705C: Glowbug gamma-ray detection of a short burst
- GRB 260706A: SVOM/ECLAIRs refined analysis
- GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- GRB 260706A: SVOM/GRM observation
- GRB 260706A: REM optical/NIR observations
- IceCube-260704A: No candidates from the Zwicky Transient Facility
- GRB 260706A: LCO optical upper limit
- GRB 260706A: EP-FXT follow-up observation
- GRB 260706A: Fermi GBM Observation
- IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
- IPN triangulation of GRB 260627A
- GRB 260705A: SVOM/ECLAIRs refined analysis
- GRB 260706A: SVOM detection of a burst
- The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
- IceCube260704A: OHP/T193 optical observations
- GRB 260705A: LCO optical upper limits
- GRB 260704A: NOT optical upper limits
- Fermi GBM Sub-Threshold Detection of GRB 260705A
- GRB 260704A: EP-FXT follow-up observation
- GRB 260629A: SVOM/GRM observation of a short burst
- GRB 260629A: GECAM-A observation of a short burst
- IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260629A: AstroSat CZTI detection
- EP260703a: EP-FXT follow-up observation
- Fermi GRB 260703A: Global MASTER-Net observations report
- GRB 260610B: VLA detection
- GRB 260623A: Glowbug gamma-ray detection
- GRB 260614B: ATCA Radio Upper Limits
- GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
- Fermi-LAT Gamma-ray Observations of IceCube-260622A
- EP260628a: EP-FXT follow-up observation
- Fermi GRB 260628A: Global MASTER-Net observations report
- EP260626a: further Liverpool Telescope optical upper limits
- EP260626a: EP-FXT follow-up observation
- EP260626a: COLIBRÍ optical upper limit
- EP260626a: Liverpool Telescope upper limits
- Konus-Wind detection of GRB 260623B / EP260623a
- EP260623a: TNG NIR afterglow detection
- GRB 260618A: Fermi GBM Observation
- MASS-Cube (GRID 2.0) detection of GRB 260616B
- EP260623a: FTW optical and NIR observations
- GRB 260619A: SVOM/ECLAIRs refined analysis
- EP260623a: Liverpool Telescope optical observations
- Konus-Wind detection of GRB 260618B
- GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
- EP260623a:refined analysis of the EP-WXT and EP-FXT observation
- EP260623a: WINTER J-band observations
- GRB 260617A: Glowbug gamma-ray detection of a short burst
- IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
- IPN triangulation of GRB 260605A
- EP260623a: Optical follow-up observations with Kinder
- EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
- EP260623a: SVOM/VT optical observations
- EP260623a: TRT optical observations
- EP260623a: REM optical/NIR afterglow detection