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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"

18572 results found.

  1. GRB 050128: Radio observations
  2. Further analysis of the short Swift-BAT GRB 050202
  3. GRB 050202: Second epoch radio observations
  4. GRB050202: Radio Observations
  5. GRB 050202: Short burst detected by Swift-BAT
  6. SGR1806-20: Swift-BAT detection of a large normal burst
  7. GRB050128: Faulkes Telescope South observations
  8. GRB050128,optical observations
  9. GRB050126: Updated Swift XRT Position
  10. GRB 050126: Radio Observations
  11. GRB050128 Swift-BAT observations
  12. GRB 050128: Swift XRT prompt afterglow position
  13. GRB 050124: K-band afterglow observations
  14. GRB050126: MASTER optical limit for KECK OT
  15. GRB050126: Burst Parameters Measured by BAT
  16. GRB050126: MASTER optical observations
  17. GRB 050126: Prompt XRT detection and localization
  18. GRB050124: No Swift UVOT Detection of Afterglow Emission
  19. GRB 050117a: Radio Observations
  20. GRB050124,optical observation
  21. GRB050124: Updated Swift XRT Position and Fluxes
  22. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  23. GRB050124: Refined BAT position, spectral and fluence information
  24. GRB050124: Swift-BAT position of a double-peaked burst
  25. GRB050117a: Radio Observations
  26. GRB050117a: Refined analysis
  27. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  28. GRB050117b: Swift-BAT detection of a weak burst
  29. GRB050117: optical observation
  30. GRB 050117, I-band observations
  31. GRB 050117: Optical observation
  32. GRB050117: Refined XRT position
  33. GRB050117: MASTER optical observations
  34. MASTER:GRB050117 SWIFT
  35. GRB050117: Swift-BAT detection of a long multi-peaked burst
  36. GRB050117: Swift XRT Position
  37. SGR1806-20: Swift-BAT observations of two additional bursts
  38. SGR 1806-20, RHESSI observations of the 041227 giant flare
  39. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  40. GRB 041217: Optical observations
  41. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  42. GRB041228: ROTSE-III Optical Observations
  43. GRB041228: Swift-BAT detection of a burst
  44. GRB041219; RXTE ASM Observations
  45. NIR Observations of GRB 041219
  46. GRB041226: ROTSE-III Optical Observations
  47. GRB041226: Swift-BAT detection of a burst
  48. GRB041223: decay of the afterglow
  49. GRB041224: ROTSE-III Optical Observations
  50. GRB 041223: XRT afterglow spectrum and light curve
  51. GRB 041223 Fluence measured by Swift-BAT
  52. GRB041224: Swift-BAT detection of a soft burst
  53. GRB041223: optical and NIR observations with REM
  54. Swift-BAT Time History of GRB041219
  55. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  56. GRB041223: ROTSE-III Optical Observations
  57. GRB041223: Swift-BAT detection of a bright long burst
  58. GRB041220: Swift-BAT burst
  59. GRB 041219 Optical Observations
  60. GRB041219c: Third Burst in One Day from Swift-BAT
  61. GRB041219b: A Swift-BAT burst
  62. Swift-BAT detection of the bright long burst GRB041219
  63. GRB041217: optical limit 30 min after GRB
  64. GRB041217: Optical Observations
  65. GRB041217: NIR and optical observations with REM
  66. GRB041217: P60 Optical Observations
  67. GRB041217: Infrared Observations
  68. GRB041217: The First GRB Located On-Board Swift
  69. GRB040916: Optical observations
  70. GRB040422: optical and NIR observations at the VLT
  71. GRB040223, improved XMM position
  72. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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