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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"

31 results found.

  1. GRB 250702F: Swift-BAT refined analysis
  2. GRB 250702F: radio detection with the VLA
  3. GRB 250702F: GRANDMA observations
  4. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  5. GRB 250702F: Kilonova-Catcher optical afterglow detection
  6. GRB 250702F: Monte Agliale Observatory optical observations
  7. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  8. Konus-Wind detection of GRB 250702F
  9. GRB 250702F: GROWTH-India Telescope optical observations
  10. GRB 250702F: optical photometry from Konkoly
  11. GRB 250702F: SVOM/VT optical observation
  12. GRB 250702F: Swift/UVOT Detection
  13. GRB 250702F: Swift-XRT refined Analysis
  14. GRB 250702F: Fermi GBM Observation
  15. GRB 250702F: Leavitt Observatory optical observations
  16. GRB 250702F: AKO Optical Afterglow Detection
  17. GRB 250702F: Skynet Optical Observations
  18. GRB 250702F: TRT Optical Observation
  19. GRB 250702F: REM optical afterglow detection
  20. GRB 250702F: DDOTI Optical Observation
  21. GRB 250702F: COLIBRÍ Observations of the Afterglow
  22. GRB 250702F: Enhanced Swift-XRT position
  23. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  24. GRB 250702F: NOT observations of the optical afterglow
  25. GRB 250702F: MASTER optical afterglow observation
  26. Fermi GRB 250702F: Global MASTER-Net observations report
  27. GRB 250702F: GOTO optical counterpart detection
  28. GRB 250702F: Ondrejov D50 optical afterglow detection
  29. GRB 250702F: Swift detection of a burst with an optical counterpart
  30. Swift GRB 250702F: Global MASTER-Net observations report
  31. GRB 250702F: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive:
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