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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').
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"

24 results found.

  1. GRB 250520A: Swift-BAT refined analysis
  2. GRB 250520A: Gemini-South optical afterglow detection
  3. GRB 250520A: 3 GHz MeerKAT Detection
  4. GRB 250520A: 10 GHz VLA Afterglow Confirmation
  5. GRB 250520A: GRBAlpha detection
  6. GRB 250520A: CALET Gamma-Ray Burst Monitor detection
  7. GRB 250520A: 10 GHz VLA radio source
  8. Konus-Wind detection of GRB 250520A (short/hard)
  9. GRB 250520A: VLT/FORS2 Optical Observation
  10. GRB 250520A: Swift/UVOT Upper Limits
  11. GRB 250520A: J-band observations with WINTER
  12. GRB 250520A: Gemini-South optical observations
  13. GRB 250520A: Swift-XRT refined Analysis
  14. GRB 250520A: REM optical/NIR early observations
  15. GRB 250520A:SVOM/VT optical candidate
  16. GRB 250520A: COLIBRÍ optical upper limit
  17. GRB 250520A: DDOTI Optical Upper Limit
  18. GRB 250520A: AstroSat CZTI detection of a short burst
  19. GRB 250520A: SVOM/GRM observation
  20. GRB 250520A: Enhanced Swift-XRT position
  21. GRB 250520A: GOTO optical upper limit
  22. GRB 250520A: Prompt enhanced Swift-XRT position
  23. GRB 250520A: Swift detection of a burst
  24. Swift GRB 250520A: Global MASTER-Net observations report

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