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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: MASTER prompt optical observations
  2. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  3. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  4. Possible GRB 081211B: Swift/UVOT Upper Limits
  5. GRB 081213: Fermi GBM detection
  6. GRB 081210: optical observations
  7. Possible GRB 081211B - Swift-XRT analysis
  8. GRB 081207: Fermi GBM detection
  9. GRB 081209: Fermi GBM detection
  10. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  11. GRB 081007: Detection of a Supernova
  12. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  13. GRB 081210: Xinglong TNT R band Upper Limits
  14. GRB 081210, SMARTS optical/IR observations
  15. GRB 081211: Swift-BAT refined analysis
  16. GRB 081211: Swift XRT refined analysis
  17. GRB 081211: Swift/UVOT detection of an optical afterglow
  18. GRB 081211: Enhanced Swift-XRT position
  19. GRB 081210: Swift/UVOT refined analysis
  20. GRB 081211: Swift detection of a burst
  21. GRB 081210: Swift-XRT refined analysis
  22. GRB081203B: optical observations
  23. GRB 081210: Enhanced Swift-XRT position
  24. GRB 081210: Swift-BAT refined analysis
  25. GRB 081210: Swift detection of a burst with optical afterglow
  26. Konus-Wind observation of GRB 081209
  27. IPN triangulation of short hard GRB 081209
  28. GRB 081203A: optical observations
  29. GRB 081206C: Fermi GBM detection
  30. Radio observation of GRB 081121 with ATCA
  31. Radio observation of GRB 081118 with ATCA
  32. GRB 081206B: Fermi GBM detection
  33. GRB 081206: Fermi GBM detection
  34. GRB 081128: afterglow observations
  35. GRB 081203B: Suzaku WAM observation of the prompt emission
  36. GRB 081203B: Additional Gemini imaging
  37. Radio observation of GRB 081109 with ATCA
  38. Radio observation of GRB 081104 with ATCA
  39. Radio observation of GRB 081029 with ATCA
  40. Radio observation of GRB 081008 with ATCA
  41. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  42. GRB 081203B: Gemini observations
  43. GRB 081128: optical observation in CrAO
  44. GRB081203A: Optical observations at Ishigaki
  45. GRB 081128: Optical afterglow observations
  46. GRB 081204: GROND Observations
  47. GRB081203B: optical observations
  48. Radio detection of GRB 081203B with the VLA
  49. GRB 081204: Magellan observations
  50. GRB081203A: Radio upper limit at 15 GHz
  51. GRB 081204B: Fermi GBM detection
  52. GRB 081204: Swift/UVOT Upper Limits
  53. GRB 081204: Swift XRT afterglow confirmation
  54. GRB081203A: MITSuME optical observation
  55. GRB 081203A: Optical observations of Xinglong TNT telescope
  56. GRB 081203A: Skynet/GORT Detections
  57. GRB 081204: Swift XRT afterglow candidate
  58. GRB081203A: optical observation
  59. GRB 081204 : a long GRB localized by INTEGRAL
  60. VLA Radio upper limit on GRB 081203A
  61. Swift-XRT observations of GRB 081203B
  62. Konus-Wind observation of GRB 081203A
  63. Konus-Wind observation of GRB 081203B
  64. GRB081203A: Swift-XRT refined analysis
  65. GRB 081203B: optical observations
  66. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  67. Swift/UVOT detection of GRB081203B
  68. GRB 081203B: Swift-XRT candidate afterglow.
  69. GRB 081203A: optical observations
  70. Swift UVOT observations of GRB 081203A
  71. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  72. GRB081203A: Swift/UVOT grism redshift
  73. GRB 081203A: Burst detection from Swift-BAT slew data
  74. GRB 081203A: Swift-BAT refined analysis
  75. GRB 081203: Enhanced Swift-XRT position
  76. GRB 081130B: MASTER prompt optical observations
  77. GRB081203: optical observation
  78. GRB 081203: Swift detection of a burst with a bright optical counterpart
  79. GRB 081128: optical observation
  80. GRB 081130B: Fermi GBM detection
  81. GRB 081130: Fermi GBM detection
  82. Swift Trigger 335971: Swift/UVOT Observations
  83. GRB 081126: afterglow photometry
  84. GRB 081126: Fermi GBM detection
  85. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  86. VLA Radio upper limit on GRB 081126
  87. GRB 081129: Fermi GBM detection
  88. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  89. GRB 081128A: optical observations
  90. Swift Trigger 335971 is probably not a real source
  91. Trigger 335971: Swift possible detection of a burst
  92. GRB081128: Swift/UVOT Upper Limits
  93. SGR 1806-20: Fermi GBM detection.
  94. GRB 081122B: Fermi GBM Detection
  95. GRB 081128: Swift-XRT refined analysis
  96. GRB 081128: Liverpool Telescope afterglow confirmation
  97. GRB081128: optical observations
  98. GRB081128 : Lulin optical follow-ups
  99. GRB 081128: Swift-BAT refined analysis
  100. GRB 081128: Enhanced Swift-XRT position

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