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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"

18651 results found.

  1. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  2. GRB050124: Refined BAT position, spectral and fluence information
  3. GRB050124: Swift-BAT position of a double-peaked burst
  4. GRB050117a: Radio Observations
  5. GRB050117a: Refined analysis
  6. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  7. GRB050117b: Swift-BAT detection of a weak burst
  8. GRB050117: optical observation
  9. GRB 050117, I-band observations
  10. GRB 050117: Optical observation
  11. GRB050117: Refined XRT position
  12. GRB050117: MASTER optical observations
  13. MASTER:GRB050117 SWIFT
  14. GRB050117: Swift-BAT detection of a long multi-peaked burst
  15. GRB050117: Swift XRT Position
  16. SGR1806-20: Swift-BAT observations of two additional bursts
  17. SGR 1806-20, RHESSI observations of the 041227 giant flare
  18. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  19. GRB 041217: Optical observations
  20. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  21. GRB041228: ROTSE-III Optical Observations
  22. GRB041228: Swift-BAT detection of a burst
  23. GRB041219; RXTE ASM Observations
  24. NIR Observations of GRB 041219
  25. GRB041226: ROTSE-III Optical Observations
  26. GRB041226: Swift-BAT detection of a burst
  27. GRB041223: decay of the afterglow
  28. GRB041224: ROTSE-III Optical Observations
  29. GRB 041223: XRT afterglow spectrum and light curve
  30. GRB 041223 Fluence measured by Swift-BAT
  31. GRB041224: Swift-BAT detection of a soft burst
  32. GRB041223: optical and NIR observations with REM
  33. Swift-BAT Time History of GRB041219
  34. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  35. GRB041223: ROTSE-III Optical Observations
  36. GRB041223: Swift-BAT detection of a bright long burst
  37. GRB041220: Swift-BAT burst
  38. GRB 041219 Optical Observations
  39. GRB041219c: Third Burst in One Day from Swift-BAT
  40. GRB041219b: A Swift-BAT burst
  41. Swift-BAT detection of the bright long burst GRB041219
  42. GRB041217: optical limit 30 min after GRB
  43. GRB041217: Optical Observations
  44. GRB041217: NIR and optical observations with REM
  45. GRB041217: P60 Optical Observations
  46. GRB041217: Infrared Observations
  47. GRB041217: The First GRB Located On-Board Swift
  48. GRB040916: Optical observations
  49. GRB040422: optical and NIR observations at the VLT
  50. GRB040223, improved XMM position
  51. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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