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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"
  1. GRB 081210: Swift-BAT refined analysis
  2. GRB 081210: Swift detection of a burst with optical afterglow
  3. Konus-Wind observation of GRB 081209
  4. IPN triangulation of short hard GRB 081209
  5. GRB 081203A: optical observations
  6. GRB 081206C: Fermi GBM detection
  7. Radio observation of GRB 081121 with ATCA
  8. Radio observation of GRB 081118 with ATCA
  9. GRB 081206B: Fermi GBM detection
  10. GRB 081206: Fermi GBM detection
  11. GRB 081128: afterglow observations
  12. GRB 081203B: Suzaku WAM observation of the prompt emission
  13. GRB 081203B: Additional Gemini imaging
  14. Radio observation of GRB 081109 with ATCA
  15. Radio observation of GRB 081104 with ATCA
  16. Radio observation of GRB 081029 with ATCA
  17. Radio observation of GRB 081008 with ATCA
  18. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  19. GRB 081203B: Gemini observations
  20. GRB 081128: optical observation in CrAO
  21. GRB081203A: Optical observations at Ishigaki
  22. GRB 081128: Optical afterglow observations
  23. GRB 081204: GROND Observations
  24. GRB081203B: optical observations
  25. Radio detection of GRB 081203B with the VLA
  26. GRB 081204: Magellan observations
  27. GRB081203A: Radio upper limit at 15 GHz
  28. GRB 081204B: Fermi GBM detection
  29. GRB 081204: Swift/UVOT Upper Limits
  30. GRB 081204: Swift XRT afterglow confirmation
  31. GRB081203A: MITSuME optical observation
  32. GRB 081203A: Optical observations of Xinglong TNT telescope
  33. GRB 081203A: Skynet/GORT Detections
  34. GRB 081204: Swift XRT afterglow candidate
  35. GRB081203A: optical observation
  36. GRB 081204 : a long GRB localized by INTEGRAL
  37. VLA Radio upper limit on GRB 081203A
  38. Swift-XRT observations of GRB 081203B
  39. Konus-Wind observation of GRB 081203A
  40. Konus-Wind observation of GRB 081203B
  41. GRB081203A: Swift-XRT refined analysis
  42. GRB 081203B: optical observations
  43. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  44. Swift/UVOT detection of GRB081203B
  45. GRB 081203B: Swift-XRT candidate afterglow.
  46. GRB 081203A: optical observations
  47. Swift UVOT observations of GRB 081203A
  48. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  49. GRB081203A: Swift/UVOT grism redshift
  50. GRB 081203A: Burst detection from Swift-BAT slew data
  51. GRB 081203A: Swift-BAT refined analysis
  52. GRB 081203: Enhanced Swift-XRT position
  53. GRB 081130B: MASTER prompt optical observations
  54. GRB081203: optical observation
  55. GRB 081203: Swift detection of a burst with a bright optical counterpart
  56. GRB 081128: optical observation
  57. GRB 081130B: Fermi GBM detection
  58. GRB 081130: Fermi GBM detection
  59. Swift Trigger 335971: Swift/UVOT Observations
  60. GRB 081126: afterglow photometry
  61. GRB 081126: Fermi GBM detection
  62. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  63. VLA Radio upper limit on GRB 081126
  64. GRB 081129: Fermi GBM detection
  65. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  66. GRB 081128A: optical observations
  67. Swift Trigger 335971 is probably not a real source
  68. Trigger 335971: Swift possible detection of a burst
  69. GRB081128: Swift/UVOT Upper Limits
  70. SGR 1806-20: Fermi GBM detection.
  71. GRB 081122B: Fermi GBM Detection
  72. GRB 081128: Swift-XRT refined analysis
  73. GRB 081128: Liverpool Telescope afterglow confirmation
  74. GRB081128: optical observations
  75. GRB081128 : Lulin optical follow-ups
  76. GRB 081128: Swift-BAT refined analysis
  77. GRB 081128: Enhanced Swift-XRT position
  78. GRB 081128: Optical observation of xinglong TNT
  79. GRB 081128: Swift detection of a burst
  80. GRB 081126: Swift observations continuing
  81. GRB081126: Afterglow photometry from Crni Vrh
  82. GRB 081126: GRT Optical Observation
  83. GRB 081127: Swift/UVOT Upper Limits
  84. GRB 081127: Swift-XRT refined analysis
  85. GRB 081127: Enhanced Swift-XRT position
  86. GRB 081126: Confirmation of the Optical Afterglow
  87. GRB 081127: Swift-BAT refined analysis
  88. Konus-Wind observation of GRB 081126
  89. GRB 081126: Swift-XRT refined analysis
  90. GRB 081127: Swift detection of a burst
  91. GRB 081126: Swift/UVOT Observations
  92. GRB 081126: optical observations
  93. GRB 081126: Swift-BAT refined analysis
  94. GRB 081126: Enhanced Swift-XRT position
  95. GRB 081126: TAROT Calern observatory optical observations
  96. GRB 081126: Swift detection of a burst
  97. GRB 081125: Fermi GBM detection
  98. GRB 081124: Fermi GBM detection
  99. GRB 081120: Fermi GBM detection
  100. GRB 081118: Fermi GBM detection.

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