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"28050 results found.
- GRB 210826A: further Swift-XRT observations
- GRB 210909B: GECAM detection
- Swift detection of a burst from SGR Swift J1555.2-5402
- GECAM observation of a burst from SGR J1935+2154
- GECAM observation of a burst from SGR J1935+2154
- Fermi trigger No 652927551: Global MASTER-Net observations report
- GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
- GRB 210905A: Swift/UVOT Upper Limits
- GRB 210905A: AstroSat CZTI detection
- GRB 210905A, GROND observations
- Fermi GBM Sub-Threshold Detection of GRB 210905A
- GRB 210905A: Swift-XRT refined Analysis
- GRB 210610A: Maidanak and AbAO optical observations
- GRB 210827B: GECAM detection
- GRB 210905A: REM NIR afterglow detection
- GRB 210905A: Continued LCO Optical Observations
- GRB 210905A: LCO Optical Detection
- GRB 210905A: Enhanced Swift-XRT position
- GRB 210901A: Swift/UVOT Upper Limits
- GRB 210905A: Swift detection of a burst
- GRB 210820A: TSHAO optical upper limit
- GRB 210901A: GROND observations
- GRB 210901A: Swift-XRT refined Analysis
- GRB 210901A: Swift-BAT refined analysis
- GRB 210901A: Enhanced Swift-XRT position
- GRB 210901A: LCO Optical Upper Limit
- GRB 210901A: Swift detection of a burst
- GRB 210827A: further Swift-XRT observations
- GRB 210827A: Fermi GBM Observation
- GRB 210826A: AstroSat CZTI detection
- Fermi GRB 210827A: Global MASTER-Net observations report
- GRB 210827A: Swift-XRT observations
- GRB 210827A: Swift/BAT-GUANO detection and arcminute localization
- GRB 210820A: CAHA 2.2m Optical Detection
- GRB 210824A: Swift/UVOT Upper Limits
- GRB 210826A: Swift/UVOT Upper Limits
- POLAR detection of a SGR-like burst
- GRB 210827B: BALROG localization (Fermi Trigger 651751821 / GRB 210827424)
- GRB 210826A: Swift-XRT observations
- GRB 210824A: Swift-BAT refined analysis
- GRB 210824A: MITSuME Akeno optical upper limits
- GRB 210826A: BALROG localization (Fermi Trigger 651654110 / GRB 210826293)
- Swift GRB210825.29: Global MASTER-Net observations report
- Swift detection of an outburst from SGR Swift J1555.2-5402
- GRB 210822A: Swift/UVOT Detection
- GRB 210824A: Fermi GBM Observation
- GRB 210824A: Nanshan/NEXT optical upper limit
- GRB 210824A: Swift-XRT refined Analysis
- GRB 210822A: GROND observations
- GRB 210824A: Enhanced Swift-XRT position
- GRB 210824A: Swift detection of a burst
- GRB 210822B: DDOTI Upper Limits on the Afterglow
- GRB 210820A: GROND observations
- Konus-Wind detection of GRB 210822A
- GRB 210822A: AstroSat CZTI detection
- GRB 210822A: NOT photometry and spectroscopy
- GRB 210822A: Swift-XRT refined Analysis
- GRB 210822A: Swift-BAT refined analysis
- GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
- GRB 210820A: Swift/UVOT Detection
- GRB 210822A: Nanshan/NEXT optical observations
- GRB 210822A: Enhanced Swift-XRT position
- GRB 210822A: RATIR Optical Detections
- GRB 210822A: Swift detection of a burst with an optical afterglow
- GRB 210820A: Swift-BAT refined analysis
- GRB 210820A: LCO Optical Upper Limit
- GRB 210820A: RATIR Optical Detections
- GRB 210820A: NOT optical upper limit
- GRB 210820A: Nanshan/NEXT optical upper limit
- GRB 210820A: Swift-XRT refined Analysis
- GRB 210820A: Enhanced Swift-XRT position
- GRB 210820A: Swift detection of a burst with an optical counterpart
- GRB 210818A: Swift-XRT refined Analysis
- GRB 210818A: Swift-BAT refined analysis
- Swift Trigger 1069242 is Cyg X-1
- GRB 210818A: AstroSat CZTI detection
- GRB 210818A: Enhanced Swift-XRT position
- GRB 210818A: Swift detection of a burst with an optical counterpart
- IceCube-210811A: Upper limits from a search for additional neutrino events in IceCube
- GRB 210815A: BALROG localization (Fermi Trigger 650687034 / GRB 210815100)
- GRB 210712A: Fermi GBM observation
- GRB 210813A: BALROG localization (Fermi Trigger 650508868 / GRB 210813038)
- Fermi-LAT Gamma-ray Observations of IceCube-210811A
- GRB 210812A: BALROG localization (Fermi Trigger 650479626 / GRB 210812699)
- GRB 080101A: Fermi GBM Final Real-time Localization
- GRB 210730A: Tautenburg observations
- GRB 210807A: Tautenburg observations
- GRB 210807C: Swift-BAT refined analysis
- GRB 210807A: Swift-BAT refined analysis
- GRB 210807C: Swift-XRT refined Analysis
- GRB 210807C: Fermi GBM detection
- GRB 210807C: Swift/UVOT Upper Limits
- GRB 210807A: Swift/UVOT Detection
- GRB 210807A: Swift-XRT refined Analysis
- GRB 210807C: Enhanced Swift-XRT position
- GRB 210610B: Assy optical observations
- GRB 210807C: Swift detection of a burst
- GRB 210807A: Enhanced Swift-XRT position
- GRB 210807A: Swift detection of a burst with an optical counterpart
- IPN Triangulation of a bright burst from SGR 1935+2154