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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 250610B: J band upper limit by SYSU 80cm infrared telescope
  2. GRB 250610B: Swift-XRT refined Analysis
  3. GRB 250610B: Liverpool Telescope continued monitoring
  4. GRB 250610B: MISTRAL/T193 and T120 OHP further observations
  5. GRB 250610B - SVOM/ECLAIRs refined analysis
  6. Fermi GBM Sub-Threshold Detection of GRB 250610B
  7. GRB 250610B: Swift/UVOT Detection
  8. GRB 250610B: SVOM/COLIBRÍ (FM-GFT) optical observations
  9. GRB 250610B: REM optical/NIR observations
  10. GRB 250610B: SVOM/VT optical shallow decay
  11. GRB 250610B: additional Liverpool Telescope optical observations
  12. GRB 250610B: SVOM/GRM analysis
  13. GRB 250610B: Fermi/GBM sub-threshold detection of a possibly hard burst
  14. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  15. GRB 250610B: Swift-XRT counterpart detection
  16. GRB 250610B: SVOM/VT optical counterpart
  17. GRB 250610B: LT detection of the optical counterpart
  18. GRB 250610B: OHP/T120 optical counterpart candidate
  19. GRB 250610B: GOTO optical upper limit
  20. GRB 250610B : SVOM/GWAC-F60A and F50 observations
  21. GRB 250610B: SVOM detection of a long burst

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