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"
- Swift BAT Trigger 1107209 is not an astrophysical event
- GRB 220514A: AstroSat CZTI detection
- GRB 220518A: Swift-BAT refined analysis
- Swift GRB220519.84: Global MASTER-Net observations report
- GRB 220518A: Swift-XRT refined Analysis
- Fermi GRB 220518B: Global MASTER-Net observations report
- Continued Chandra monitoring of GW170817 at ~4.8 yr post-merger
- GRB 220518B: Fermi GBM Final Real-time Localization
- GRB 220518A: Swift/UVOT Detection
- GRB 220518A: Enhanced Swift-XRT position
- Swift GRB 220518A: Global MASTER-Net observations report
- GRB 220518A: Swift detection of a burst
- GRB 220514A: MITSuME Akeno optical observation
- GRB 220514A: GRANDMA Optical Afterglow Observations
- Konus-Wind detection of GRB 220506A
- Konus-Wind detection of GRB 220514B
- Fermi trigger No 674397342: Global MASTER-Net observations report
- GRB 220514A: Fermi GBM observation
- GRB 220514B: Swift-XRT observations
- GRB 220511A: Swift-XRT afterglow detection
- GRB 220514A: KAIT Optical Afterglow Confirmation
- Fermi-LAT Gamma-ray Observations of IceCube-220513A
- IceCube-220513A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220514B: Tiled Swift observations
- IceCube-220513A: No significant detection in HAWC
- GRB 220514B: MAXI/GSC detection
- MAXI GRB220514.98: Global MASTER-Net observations report
- GRB 220514A: MeerLICHT optical afterglow candidate
- Integral GRB220514.52: Global MASTER-Net observations report
- Fermi GRB 220514A: Global MASTER-Net observations report
- GRB 220514A: a long GRB detected by INTEGRAL
- IceCube-220513A: No Candidate Counterparts from the Zwicky Transient Facility
- GRB 220514A: BALROG localization (Fermi Trigger 674223877 / GRB 220514517)
- GRB 220514A: Fermi GBM Final Real-time Localization
- IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube Alert 220513.97: Global MASTER-Net observations report
- Fermi GRB 220513A: Global MASTER-Net observations report
- GRB 220513A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 220511A
- GRB 220427A: MeerLICHT afterglow observations
- IceCube-220509A: No significant detection in HAWC
- GRB 220511A: Fermi GBM observation
- GRB 220511A: Swift-XRT observations
- GRB 220511A: AstroSat CZTI detection
- GRB 220511A: BOOTES-2/TELMA optical upper limit
- Fermi GRB 220512A: Global MASTER-Net observations report
- GRB 220512A: Fermi GBM Final Real-time Localization
- GRB 220511A: Swift ToO observations
- GRB 220511A: Swift/BAT-GUANO arcminute localization
- Fermi GRB 220511A: Global MASTER-Net observations report
- GRB 220511A: AGILE detection
- IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220511A: BALROG localization (Fermi Trigger 673969321/ GRB 220511571)
- GRB 220511A: Fermi GBM Final Real-time Localization
- GRB 220507A: AstroSat CZTI detection
- Fermi-LAT Gamma-ray Observations of IceCube-220509A
- Fermi trigger No 673846271: Global MASTER-Net observations report
- GRB 220506A: MITSuME Akeno optical upper limits
- IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220506A: GIT optical upper limit.
- 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