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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- IceCube Alert 220509.76: Global MASTER-Net observations report
- GRB 220508A: Fermi GBM Final Real-time Localization
- GRB 220507A: Fermi GBM Final Localization
- GRB 220506A: BOOTES-5/JGT optical upper limit
- Fermi trigger No 673610950: Global MASTER-Net observations report
- GRB 220506A: Swift-XRT afterglow detection
- GRB 220506A: Tiled Swift observations
- IceCube-220405B - ZTF19aavnpjv unrelated
- Swift-BAT triggers 1105560-1 are not GRBs
- Swift GRB220506.51: Global MASTER-Net observations report
- GRB 220506A/MAXI J1558-266: MAXI/GSC detection
- MAXI GRB220506.27: Global MASTER-Net observations report
- GRB 220430A: Nanshan/NEXT optical upper limit
- GRB 220430A: Nanshan/HMT optical upper limit
- GRB 220430A: GIT optical upper limits
- IPN triangulation of GRB 220423A
- GRB 220427A: LCO Optical Observations
- IceCube-220501A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220501A: Swift-BAT refined analysis
- Fermi-LAT Gamma-ray Observations of IceCube-220501A
- GRB 220427A: GRANDMA Early Optical Afterglow Detection
- GRB 220501A: BOOTES-1 optical upper limit
- IceCube-220501A: No Candidate Counterparts from the Zwicky Transient Facility
- GRB 220501A: Fermi GBM observation
- GRB 220430A: AstroSat CZTI detection
- IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube Alert 220501.95: Global MASTER-Net observations report
- GRB 220501A: GRANDMA/TJML Optical Observations
- GRB 220501A: Fermi GBM Final Real-time Localization
- GRB 220501A: Swift detection of a burst
- GRB 220430A: Swift-BAT refined analysis
- GRB 220430A: CAHA 2.2m telescope optical limit
- GRB 220430A: Swift-XRT refined Analysis
- Swift GRB 220430A: Global MASTER-Net observations report
- GRB 220430A: GRANDMA observations
- GRB 220430A: Mondy and AbAO optical upper limits
- GRB 220430A: AGILE detection
- GRB 220430A: MeerLICHT optical upper limits
- GRB 220430A: Enhanced Swift-XRT position
- GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
- IceCube-220425A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-220424A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-220421A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220427A: Swift-BAT refined analysis
- GRB 220427A: VLT/X-shooter photometry
- GRB 220426A: Swift-XRT and UVOT observations
- GRB 220423A: Detection by VZLUSAT-2
- Konus-Wind detection of GRB 220427A
- GRB 220427A: Swift-XRT refined Analysis
- GRB 220427A: Enhanced Swift-XRT position
- GRB 220426A: Tiled Swift observations
- GRB 220427A: Swift detection of a burst with an optical counterpart
- Konus-Wind detection of GRB 220426A
- IPN triangulation of GRB 220426A
- GRB 220426C: Swift/BAT-GUANO detection outside the coded FOV (short)
- Fermi GRB 220426A: Global MASTER-Net observations report
- GRB 220426A: Fermi GBM detection
- GRB 220426A: Swift/BAT-GUANO detection outside the coded FOV
- Fermi-LAT Gamma-ray Observations of IceCube-220425A
- Fermi GRB 220426B: Global MASTER-Net observations report
- GRB 220426B: Fermi GBM Final Real-time Localization
- GRB 220426A: BALROG localization (Fermi Trigger 672648596/ GRB 220426285)
- Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
- IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
- Fermi-LAT Gamma-ray Observations of IceCube-220424A
- IceCube Alert 220425.11: Global MASTER-Net observations report
- Fermi trigger No 672492774: Global MASTER-Net observations report
- IceCube-220425A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
- IceCube-220424A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube Alert 220424.05: Global MASTER-Net observations report
- Fermi trigger No 672374264: Global MASTER-Net observations report
- On the AGILE detection of GRB 220423A
- GRB 220423A: AGILE detection
- GRB 220421B: Detection by VZLUSAT-2
- GRB 220421A: Fermi GBM observation
- Fermi-LAT Gamma-ray Observations of IceCube-220421A
- GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
- Fermi trigger No 672221879: Global MASTER-Net observations report
- Fermi GBM trigger 672128054/220420260 is not a GRB
- IceCube-220421A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220418B: Swift-XRT observations
- IceCube Alert 220421.22: Global MASTER-Net observations report
- GRB 220418B Fermi GBM observation
- Fermi trigger No 672093919: Global MASTER-Net observations report
- “GRB 220420A” is not a GRB
- GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220403C: Further Swift-XRT observations
- GRB 220418B: Swift ToO observations
- GRB 220417A: Fermi GBM detection
- GRB 220418B: Swift/BAT-GUANO refined location of a short burst
- IPN triangulation of GRB 220411A
- GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
- GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220412B: Swift/UVOT Upper Limits
- Fermi GRB 220418A: Global MASTER-Net observations report
- GRB 220418B: Fermi GBM Final Real-time Localization
- GRB 220418A: Fermi GBM Final Real-time Localization
- Fermi GRB 220417A: Global MASTER-Net observations report
- GRB 220417A: Fermi GBM Final Real-time Localization