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"26042 results found.
- GRB 220706A: Swift-BAT refined analysis
- GRB 220708A: Enhanced Swift-XRT position
- GRB 220708B: Swift ToO observations
- GRB 220708B: Swift/BAT-GUANO arcminute localization
- GRB 220708A: Swift-XRT observations
- GRB 220708A: Swift detection of a burst
- GRB 220706A: LCO Optical Upper Limits
- GRB 220627A: ATCA detection of radio counterpart
- GRB 220706A: Swift-XRT refined Analysis
- GRB 220706A, GROND observations
- GRB 220706A: Optical observations from NOT
- GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
- GRB 220706A: Nanshan/NEXT optical upper limits
- GRB 220706A: Enhanced Swift-XRT position
- Swift GRB 220706A: Global MASTER-Net observations report
- GRB 220706A: Zadko observatory - Gingin optical observations
- GRB 220706A: Prompt enhanced Swift-XRT position
- GRB 220706A: Swift detection of a burst
- GRB 220701A: Swift-BAT refined analysis
- GRB220408A: VIRT Optical Upper Limit
- GRB220412A: VIRT Optical Upper Limit
- GRB220701A: VIRT Optical Upper Limit
- GRB 220701A: MITSuME Akeno optical upper limits
- GRB 220701A: COATLI Optical Upper Limit
- GRB 220701A: AbAO optical upper limit
- GRB 220627A: AstroSat CZTI detection
- GRB 220701A: Keck/LRIS Optical Upper Limit
- GRB 220701A: Swift-XRT refined Analysis
- GRB 220701A: LCO Optical Upper Limits
- GRB 220701A: BOOTES-5/JGT early optical upper limit
- GRB 220701A: Swift/UVOT Upper Limits
- GRB 220701A: Lowell Discovery Telescope Optical Observations
- GRB 220701A: Enhanced Swift-XRT position
- GRB 200701A: KAIT Optical Upper Limit
- GRB 220701A: Swift detection of a burst
- GRB 220627A: Swift/UVOT Upper Limits
- GRB 220627A: Swift-XRT afterglow detection
- Konus-Wind detection of GRB 220627A
- Trigger 1113743: Swift detection of MAXI J0655-013
- IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
- GRB 220627A: VLT MUSE redshift
- Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
- GRB 220627A: MeerLICHT candidate optical afterglow
- GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
- GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
- Konus-Wind detection of GRB 220624A
- GRB 220627A: Swift ToO observations
- GRB 220627A: Fermi-LAT detection
- GRB 220627A: MeerLICHT detection of two afterglow candidates
- GRB 220623A: GIT optical upper limits.
- GRB 220624A: CALET Gamma-Ray Burst Monitor detection
- GRB 220623A: T193-OHP optical upper limit
- GRB 220624A: Fermi GBM Detection
- 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
- Konus-Wind detection of GRB 220623A
- 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
- 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
- GRB 220618A: Fermi GBM detection
- Swift Detection of MAXI J0655-013
- GRB 220618A: Swift-BAT refined analysis
- GRB 220618A: iTelescope T-19 upper limit
- Swift GRB220620.02: Global MASTER-Net observations report
- GRB 220611A: Continued Gemini Infrared Observations
- GRB 220617A: TNG optical observations
- Swift Trigger 1110865 is probably not an astrophysical event
- 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
- GRB 220611A: Gemini South Infrared Detection
- GRB 220611A: Swift/UVOT Upper Limits
- GRB 220612A: CALET Gamma-Ray Burst Monitor detection
- GRB 220612A: Swift/BAT-GUANO detection
- GRB 220611A: Swift-BAT refined analysis
- Swift GRB 220611A: Global MASTER-Net observations report
- GRB 220611A: Swift-XRT refined Analysis
- GRB 220611A: Enhanced Swift-XRT position
- GRB 220611A: Swift detection of a burst
- GRB 220606A: Fermi GBM observation
- GRB 220606B: Gemini South Optical Observations
- GRB 220606B: Fermi GBM Observation