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"- Fermi trigger No 731839490: Global MASTER-Net observations report
- Fermi-LAT gamma-ray observations of IceCube-240307A
- GRB 240310B: Glowbug gamma-ray detection
- Fermi GRB 240310A: Global MASTER-Net observations report
- Swift GRB240309.61: Global MASTER-Net observations report
- GRB 240310A: Fermi GBM Final Real-time Localization
- GRB 240309A: MAXI/GSC detection
- Swift Trigger 1219325 is not a GRB
- IceCube-240307A: Upper limits from a search for additional neutrino events in IceCube
- GRID detection of GRB 240229A (Updated Report)
- GRID detection of GRB 240229A
- GRB 240308A: Fermi GBM Final Localization
- Fermi trigger No 731571927: Global MASTER-Net observations report
- GRB 231215A: further radio observations with the VLA
- GRB 240306A: Fermi GBM observation
- IceCube-240307A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 240229A: Glowbug gamma-ray detection
- GRB 240227A (short): Glowbug gamma-ray detection
- IceCube Alert 240307.32: Global MASTER-Net observations report
- GRB 240229A: GRBAlpha detection
- Konus-Wind detection of GRB 231118A
- GRB 240306A: AstroSat CZTI detection
- Fermi GRB 240306A: Global MASTER-Net observations report
- Fermi GRB 240305A: Global MASTER-Net observations report
- GRB 240306A: Swift/BAT-GUANO detection of a burst
- GRB 240305A: Fermi GBM observation
- Fermi-LAT gamma-ray observations of IceCube-240229A
- GRB 240305C: AstroSat CZTI detection of a short burst
- GRB 240306A: Fermi GBM Final Real-time Localization
- Swift GRB240305.18: Global MASTER-Net observations report
- Swift GRB240305.16: Global MASTER-Net observations report
- Fermi GRB 240305C: Global MASTER-Net observations report
- GRB 240305C: Fermi GBM Final Real-time Localization
- GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 231028C: Glowbug gamma-ray confirmation of a prior burst
- GRB 240218A: ALMA detection
- GRB 240218A: Chandra Detection and Jet Break Confirmation
- GRB 240305B: Fermi GBM Final Localization
- Fermi trigger No 731303574: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240227A (short/hard)
- GRB 240303B: VZLUSAT-2 detection
- GRB 240229A: VZLUSAT-2 detection
- Improved IPN triangulation of GRB 240227A (short)
- IPN triangulation of GRB 240229A
- GRB 240305A: Fermi GBM Final Real-time Localization
- Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
- Swift Trigger 1218696: Another trigger on Swift J151857.0-572147
- GRB240218A: ATCA observation of the radio counterpart
- Transient EPW20240219aa: Optical observations with LDT
- Konus-Wind detection of GRB 240303B
- Swift Trigger 1218645: Another detection of Swift J151857.0-572147
- IPN triangulation of GRB 240303B
- Swift J151857.0-572147: Swift-BAT refined analysis
- GRB 240303B: Fermi GBM Detection
- GRB 240225B: Swift-XRT afterglow detection
- Swift detection of Swift J151857.0-572147
- GRB 240303B: CALET Gamma-Ray Burst Monitor detection
- Fermi trigger No 731161136: Global MASTER-Net observations report
- GRB 240303C: BALROG localization (Fermi Trigger 731189113 / GRB 240303837)
- Swift GRB 240303A: Global MASTER-Net observations report
- Swift J151857.0-572147: Confirmation of a new galactic transient
- GRB 240215A: Swift-XRT afterglow detection
- GRB 240303B: BALROG localization (Fermi Trigger 731161136 / GRB 240303513)
- GRB 240303B: Fermi GBM Final Localization
- GRB 240303A: Swift detection of a burst
- GRB 240225B: Glowbug gamma-ray detection
- IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240225C: Glowbug gamma-ray detection
- GRB 240225A (short): Glowbug gamma-ray detection
- GRB 240229A: DDOTI Upper Limits on the Afterglow
- GRB 240218A: NOEMA upper limit
- GRB 240229A: CALET Gamma-Ray Burst Monitor detection
- IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
- Swift BAT Triggers 1218081 and 1218082 are not astrophysical
- GRB 240225B: further SAO RAS optical observations
- Fermi GRB 240229A: Global MASTER-Net observations report
- IceCube Alert 240229.66: Global MASTER-Net observations report
- GRB 240225B: Swift ToO observations
- Konus-Wind detection of GRB 240225B (long)
- GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)
- GRB 240229A: Fermi GBM Final Real-time Localization
- GRB 240225B: VLT/X-shooter redshift
- GRB 240225B : MITSuME Akeno optical afterglow candidate detection
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: WINTER near-IR observations and upper limits
- GRB 240225B: SAO RAS optical observations
- GRB 240226A: GRBAlpha detection
- GRB 240225B: Mondy afterglow observations
- Fermi GRB 240227A: Global MASTER-Net observations report
- GRB 240225B: Liverpool Telescope afterglow observations
- Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up
- Swift Trigger 1217799 is not a GRB
- IPN triangulation of GRB 240227A (short)
- GRB 240225B: Liverpool Telescope optical afterglow observations
- GRB 240225B: NOT optical observations
- GRB 240218A: CMO SAI NIR upper limit
- Fermi GRB 240226A: Global MASTER-Net observations report
- Swift-BAT triggers 1217733 - 1217736 are not astrophysical events
- Swift-BAT triggers 1217729-1217732 are not astrophysical
- GRB 240227A: Fermi GBM Final Real-time Localization