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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 0811215A: Andromeda inside Fermi error box: MASTER observations
  2. Possible GRB 081211B: Swift/UVOT Upper Limits
  3. GRB 081213: Fermi GBM detection
  4. GRB 081210: optical observations
  5. Possible GRB 081211B - Swift-XRT analysis
  6. GRB 081207: Fermi GBM detection
  7. GRB 081209: Fermi GBM detection
  8. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  9. GRB 081007: Detection of a Supernova
  10. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  11. GRB 081210: Xinglong TNT R band Upper Limits
  12. GRB 081210, SMARTS optical/IR observations
  13. GRB 081211: Swift-BAT refined analysis
  14. GRB 081211: Swift XRT refined analysis
  15. GRB 081211: Swift/UVOT detection of an optical afterglow
  16. GRB 081211: Enhanced Swift-XRT position
  17. GRB 081210: Swift/UVOT refined analysis
  18. GRB 081211: Swift detection of a burst
  19. GRB 081210: Swift-XRT refined analysis
  20. GRB081203B: optical observations
  21. GRB 081210: Enhanced Swift-XRT position
  22. GRB 081210: Swift-BAT refined analysis
  23. GRB 081210: Swift detection of a burst with optical afterglow
  24. Konus-Wind observation of GRB 081209
  25. IPN triangulation of short hard GRB 081209
  26. GRB 081203A: optical observations
  27. GRB 081206C: Fermi GBM detection
  28. Radio observation of GRB 081121 with ATCA
  29. Radio observation of GRB 081118 with ATCA
  30. GRB 081206B: Fermi GBM detection
  31. GRB 081206: Fermi GBM detection
  32. GRB 081128: afterglow observations
  33. GRB 081203B: Suzaku WAM observation of the prompt emission
  34. GRB 081203B: Additional Gemini imaging
  35. Radio observation of GRB 081109 with ATCA
  36. Radio observation of GRB 081104 with ATCA
  37. Radio observation of GRB 081029 with ATCA
  38. Radio observation of GRB 081008 with ATCA
  39. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  40. GRB 081203B: Gemini observations
  41. GRB 081128: optical observation in CrAO
  42. GRB081203A: Optical observations at Ishigaki
  43. GRB 081128: Optical afterglow observations
  44. GRB 081204: GROND Observations
  45. GRB081203B: optical observations
  46. Radio detection of GRB 081203B with the VLA
  47. GRB 081204: Magellan observations
  48. GRB081203A: Radio upper limit at 15 GHz
  49. GRB 081204B: Fermi GBM detection
  50. GRB 081204: Swift/UVOT Upper Limits
  51. GRB 081204: Swift XRT afterglow confirmation
  52. GRB081203A: MITSuME optical observation
  53. GRB 081203A: Optical observations of Xinglong TNT telescope
  54. GRB 081203A: Skynet/GORT Detections
  55. GRB 081204: Swift XRT afterglow candidate
  56. GRB081203A: optical observation
  57. GRB 081204 : a long GRB localized by INTEGRAL
  58. VLA Radio upper limit on GRB 081203A
  59. Swift-XRT observations of GRB 081203B
  60. Konus-Wind observation of GRB 081203A
  61. Konus-Wind observation of GRB 081203B
  62. GRB081203A: Swift-XRT refined analysis
  63. GRB 081203B: optical observations
  64. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  65. Swift/UVOT detection of GRB081203B
  66. GRB 081203B: Swift-XRT candidate afterglow.
  67. GRB 081203A: optical observations
  68. Swift UVOT observations of GRB 081203A
  69. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  70. GRB081203A: Swift/UVOT grism redshift
  71. GRB 081203A: Burst detection from Swift-BAT slew data
  72. GRB 081203A: Swift-BAT refined analysis
  73. GRB 081203: Enhanced Swift-XRT position
  74. GRB 081130B: MASTER prompt optical observations
  75. GRB081203: optical observation
  76. GRB 081203: Swift detection of a burst with a bright optical counterpart
  77. GRB 081128: optical observation
  78. GRB 081130B: Fermi GBM detection
  79. GRB 081130: Fermi GBM detection
  80. Swift Trigger 335971: Swift/UVOT Observations
  81. GRB 081126: afterglow photometry
  82. GRB 081126: Fermi GBM detection
  83. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  84. VLA Radio upper limit on GRB 081126
  85. GRB 081129: Fermi GBM detection
  86. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  87. GRB 081128A: optical observations
  88. Swift Trigger 335971 is probably not a real source
  89. Trigger 335971: Swift possible detection of a burst
  90. GRB081128: Swift/UVOT Upper Limits
  91. SGR 1806-20: Fermi GBM detection.
  92. GRB 081122B: Fermi GBM Detection
  93. GRB 081128: Swift-XRT refined analysis
  94. GRB 081128: Liverpool Telescope afterglow confirmation
  95. GRB081128: optical observations
  96. GRB081128 : Lulin optical follow-ups
  97. GRB 081128: Swift-BAT refined analysis
  98. GRB 081128: Enhanced Swift-XRT position
  99. GRB 081128: Optical observation of xinglong TNT
  100. GRB 081128: Swift detection of a burst

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