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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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

36 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  2. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  3. GRB 250101A: Terskol Zeiss-2000 optical observations
  4. GRB 250101A: CMO RC-500 optical observations
  5. GRB 250101A: Terskol K-800 optical observations
  6. GRB 250101A: J band upper limit by SYSU 80cm telescope
  7. GRB 250101A: REM optical/NIR counterpart detection
  8. GRB 250101A: 1.3m DFOT optical afterglow detection
  9. GRB 250101A: further LCOGT optical afterglow observations
  10. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 250101a: Liverpool Telescope optical follow-up
  12. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  13. GRB 250101A: Swift-BAT refined analysis
  14. GRB 250101A: further SAO RAS optical observations
  15. GRB 250101A: LCO optical counterpart detection
  16. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  17. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  18. GRB 250101A: Swift/UVOT Detection
  19. GRB 250101A: 1.6m Mephisto multi-band optical followup
  20. GRB 250101A: Swift-XRT refined Analysis
  21. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  22. IceCube-250101A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 250101A: LCOGT optical afterglow detection
  24. GRB 250101A: OASDG optical observations
  25. GRB 250101A: SAO RAS observations of optical brightening
  26. GRB 250101A: BOOTES-4/MET optical afterglow detection
  27. GRB 250101A: AKO Optical Afterglow Detection
  28. GRB 250101A: SAO RAS optical observations
  29. GRB 250101A: Enhanced Swift-XRT position
  30. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  31. GRB 250101A: SVOM/C-GFT early optical observations
  32. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  33. GRB 250101A: Nanshan/HMT optical observations
  34. GRB 250101A : GIT optical detection
  35. GRB 250101A: GMG Optical Observation
  36. GRB 250101A: Swift detection of a burst with an optical counterpart

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