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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 250502A: Tautenburg observations
  2. GRB 250502A: TESS observations
  3. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  4. GRB 250502A: Bassano Bresciano Observatory upper limit
  5. GRB 250502A: REM optical/NIR observations
  6. GRB 250502A: Swift/UVOT Follow up
  7. GRB 250502A: Mondy and Tien-Shan Optical Observations
  8. GRB 250502A: KAIT optical observations
  9. GRB 250502A: Montarrenti Observatory optical detection
  10. GRB 250502A: Swift-XRT afterglow detection
  11. GRB 250502A: NOT optical observations
  12. GRB 250502a: Liverpool Telescope optical follow-up
  13. GRB 250502A: AKO Optical Afterglow Detection
  14. GRB 250502A: LCO optical counterpart detection
  15. GRB 250502A: Swift ToO observations
  16. GRB 250502A: Redshift from OSIRIS+/GTC z = 2.163
  17. GRB 250502A: Early optical counterpart detection by LCO.
  18. GRB 250502A: SVOM/VT optical bump
  19. GRB 250502A: TRT optical afterglow confirmation
  20. GRB 250502A: SVOM/COLIBRÍ (FM-GFT) Detection of a Bright Optical Counterpart Candidate
  21. GRB 250502A: SVOM detection of a burst

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