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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"

18634 results found.

  1. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  2. GRB 041217: Optical observations
  3. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  4. GRB041228: ROTSE-III Optical Observations
  5. GRB041228: Swift-BAT detection of a burst
  6. GRB041219; RXTE ASM Observations
  7. NIR Observations of GRB 041219
  8. GRB041226: ROTSE-III Optical Observations
  9. GRB041226: Swift-BAT detection of a burst
  10. GRB041223: decay of the afterglow
  11. GRB041224: ROTSE-III Optical Observations
  12. GRB 041223: XRT afterglow spectrum and light curve
  13. GRB 041223 Fluence measured by Swift-BAT
  14. GRB041224: Swift-BAT detection of a soft burst
  15. GRB041223: optical and NIR observations with REM
  16. Swift-BAT Time History of GRB041219
  17. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  18. GRB041223: ROTSE-III Optical Observations
  19. GRB041223: Swift-BAT detection of a bright long burst
  20. GRB041220: Swift-BAT burst
  21. GRB 041219 Optical Observations
  22. GRB041219c: Third Burst in One Day from Swift-BAT
  23. GRB041219b: A Swift-BAT burst
  24. Swift-BAT detection of the bright long burst GRB041219
  25. GRB041217: optical limit 30 min after GRB
  26. GRB041217: Optical Observations
  27. GRB041217: NIR and optical observations with REM
  28. GRB041217: P60 Optical Observations
  29. GRB041217: Infrared Observations
  30. GRB041217: The First GRB Located On-Board Swift
  31. GRB040916: Optical observations
  32. GRB040422: optical and NIR observations at the VLT
  33. GRB040223, improved XMM position
  34. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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