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.
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"- GRB 220623A: GIT optical upper limits.
- GRB 220624A: CALET Gamma-Ray Burst Monitor detection
- GRB 220623A: T193-OHP optical upper limit
- IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
- GRB 220624A: Fermi GBM Detection
- Fermi GRB 220623B: Global MASTER-Net observations report
- Fermi GRB 220624A: Global MASTER-Net observations report
- IceCube Alert 220624.68: Global MASTER-Net observations report
- IPN triangulation of GRB 220624A
- GRB 220623A: Swift-BAT refined analysis
- GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
- GRB 220624A: AGILE/GRID analysis
- IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220624A: AGILE detection
- Konus-Wind detection of GRB 220623A
- GRB 220624B: Fermi GBM Final Real-time Localization
- GRB 220624A: Fermi GBM Final Real-time Localization
- GRB 220623A: AbAO optical upper limit
- GRB 220623A: Swift-XRT refined Analysis
- GRB 220623A: NOT optical observations
- GRB 220623A: Swift/UVOT Upper Limits
- GRB 220623A: BOOTES-5/JGT optical afterglow detection
- Konus-Wind detection of GRB 220609B
- GRB 220623B: Fermi GBM Final Real-time Localization
- GRB 220623A: Enhanced Swift-XRT position
- GRB 220623A: AGILE detection
- GRB 220623A: AstroSat CZTI detection
- GRB 220623A: iTelescope optical upper limit
- GRB 220623A: Swift-XRT observations
- GRB 220623A: Swift detection of a burst
- Fermi trigger No 677597318: Global MASTER-Net observations report
- GRB 220618A: Fermi GBM detection
- Swift Detection of MAXI J0655-013
- GRB 220618A: Swift-BAT refined analysis
- GRB 220618A: iTelescope T-19 upper limit
- Konus-Wind detection of GRB 220617A
- Fermi trigger No 677377371: Global MASTER-Net observations report
- Fermi GRB 220620B: Global MASTER-Net observations report
- Fermi GRB 220620A: Global MASTER-Net observations report
- GRB 220620B: Fermi GBM Final Real-time Localization
- Integral GRB220619.53: Global MASTER-Net observations report
- GRB 220619A: AstroSat CZTI detection
- Swift GRB220620.02: Global MASTER-Net observations report
- GRB 220620A: Fermi GBM Final Real-time Localization
- GRB 220611A: Continued Gemini Infrared Observations
- GRB 220617A: TNG optical observations
- Fermi trigger No 677307509: Global MASTER-Net observations report
- Fermi trigger No 677236224: Global MASTER-Net observations report
- GRB 220617A: Fermi GBM observation
- Swift Trigger 1110865 is probably not an astrophysical event
- GRB 220611A optical counterpart
- GRB 220618A: Swift-XRT refined Analysis
- IPN triangulation of GRB 220617A (short)
- GRB 220618A: BOOTES-5/JGT early optical upper limit
- GRB 220618A: Swift/UVOT Upper Limits
- GRB220611A: Gemini Optical Afterglow Confirmation
- GRB 220618A: Enhanced Swift-XRT position
- GRB 220617A: Swift-XRT observations
- GRB 220618A: Swift detection of a burst
- Swift GRB220618.38: Global MASTER-Net observations report
- GRB 220617A: Fermi-LAT detection
- GRB 220617B: Swift ToO observations
- Fermi GRB 220617A: Global MASTER-Net observations report
- GRB 220617A: Fermi GBM Final Real-time Localization
- GRB 220611A: Gemini Ks counterpart detection
- Fermi trigger No 677174940: Global MASTER-Net observations report
- Konus-Wind detection of GRB 220613A
- IPN triangulation of GRB 220613A
- Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16
- GRB 220611A: Gemini South Infrared Detection
- IPN triangulation of GRB 220606C
- GRB 220611A: Swift/UVOT Upper Limits
- Fermi trigger No 676909037: Global MASTER-Net observations report
- GRB 220612A: CALET Gamma-Ray Burst Monitor detection
- GRB 220612A: Swift/BAT-GUANO detection
- GRB 220611A: Swift-BAT refined analysis
- GRB 220608B: Detection by VZLUSAT-2
- Swift GRB 220611A: Global MASTER-Net observations report
- GRB 220611A: Swift-XRT refined Analysis
- GRB 220610B: AstroSat CZTI detection
- GRB 220611A: Enhanced Swift-XRT position
- GRB 220611A: Swift detection of a burst
- IPN triangulation of GRB 220609B
- Fermi GRB 220610A: Global MASTER-Net observations report
- GRB 220610A: Fermi GBM Final Real-time Localization
- Fermi trigger No 676537486: Global MASTER-Net observations report
- GRB 220609B: AstroSat CZTI detection
- GRB 220609B: CALET Gamma-Ray Burst Monitor detection
- Fermi trigger No 676366592: Global MASTER-Net observations report
- GRB 220608A: AstroSat CZTI detection
- GRB 220609A: Fermi GBM Final Real-time Localization
- GRB 220606A: Fermi GBM observation
- GRB 220606C: CALET Gamma-Ray Burst Monitor detection
- Fermi GRB 220608A: Global MASTER-Net observations report
- GRB 220608A: Fermi GBM Final Real-time Localization
- GRB 220606B: Gemini South Optical Observations
- MAXI GRB220607.31: Global MASTER-Net observations report
- MAXI GRB220607.41: Global MASTER-Net observations report
- GRB 220606B: Fermi GBM Observation