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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"

21 results found.

  1. GRB 210610B: correction to GCN 30181
  2. GRB 210610B: iTelescope optical afterglow observations
  3. GRB 201223A: SVOM-GWAC detected the optical counterpart during prompt emission phase
  4. GRB 201223A: AROMA-N Optical Observation
  5. GRB 201223A: Swift/UVOT Detection
  6. GRB 201223A: HCT optical upper limit
  7. GRB 201223A: AbAO optical observations
  8. GRB 201223A: 1.3m DFOT and 1.04m ST optical observations
  9. GRB 201223A: Swift-XRT refined Analysis
  10. GRB 201223A: Enhanced Swift-XRT position
  11. GRB 201223A: NOT optical upper limit and NEXT powerlaw decay
  12. GRB 201223A: GROWTH-India Telescope (GIT) photometric follow-up.
  13. GRB 201223A: Mondy and Kitab optical observations
  14. GRB 201223A: GWAC-F60A optical afterglow observations
  15. GRB 201223A: iTelescope optical afterglow observations
  16. GRB 201223A: MITSuME Akeno optical observation
  17. GRB 201223A: Swift-BAT refined analysis
  18. GRB 201223A: Fermi GBM Detection
  19. GRB 201223A: BOOTES-4/MET early optical observation
  20. GRB 201223A: Nanshan/NEXT early optical afterglow detection
  21. GRB 201223A: Swift detection of a burst with a bright optical counterpart

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