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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 081007: Detection of a Supernova
  2. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  3. GRB 081210: Xinglong TNT R band Upper Limits
  4. GRB 081210, SMARTS optical/IR observations
  5. GRB 081211: Swift-BAT refined analysis
  6. GRB 081211: Swift XRT refined analysis
  7. GRB 081211: Swift/UVOT detection of an optical afterglow
  8. GRB 081211: Enhanced Swift-XRT position
  9. GRB 081210: Swift/UVOT refined analysis
  10. GRB 081211: Swift detection of a burst
  11. GRB 081210: Swift-XRT refined analysis
  12. GRB081203B: optical observations
  13. GRB 081210: Enhanced Swift-XRT position
  14. GRB 081210: Swift-BAT refined analysis
  15. GRB 081210: Swift detection of a burst with optical afterglow
  16. Konus-Wind observation of GRB 081209
  17. IPN triangulation of short hard GRB 081209
  18. GRB 081203A: optical observations
  19. GRB 081206C: Fermi GBM detection
  20. Radio observation of GRB 081121 with ATCA
  21. Radio observation of GRB 081118 with ATCA
  22. GRB 081206B: Fermi GBM detection
  23. GRB 081206: Fermi GBM detection
  24. GRB 081128: afterglow observations
  25. GRB 081203B: Suzaku WAM observation of the prompt emission
  26. GRB 081203B: Additional Gemini imaging
  27. Radio observation of GRB 081109 with ATCA
  28. Radio observation of GRB 081104 with ATCA
  29. Radio observation of GRB 081029 with ATCA
  30. Radio observation of GRB 081008 with ATCA
  31. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  32. GRB 081203B: Gemini observations
  33. GRB 081128: optical observation in CrAO
  34. GRB081203A: Optical observations at Ishigaki
  35. GRB 081128: Optical afterglow observations
  36. GRB 081204: GROND Observations
  37. GRB081203B: optical observations
  38. Radio detection of GRB 081203B with the VLA
  39. GRB 081204: Magellan observations
  40. GRB081203A: Radio upper limit at 15 GHz
  41. GRB 081204B: Fermi GBM detection
  42. GRB 081204: Swift/UVOT Upper Limits
  43. GRB 081204: Swift XRT afterglow confirmation
  44. GRB081203A: MITSuME optical observation
  45. GRB 081203A: Optical observations of Xinglong TNT telescope
  46. GRB 081203A: Skynet/GORT Detections
  47. GRB 081204: Swift XRT afterglow candidate
  48. GRB081203A: optical observation
  49. GRB 081204 : a long GRB localized by INTEGRAL
  50. VLA Radio upper limit on GRB 081203A
  51. Swift-XRT observations of GRB 081203B
  52. Konus-Wind observation of GRB 081203A
  53. Konus-Wind observation of GRB 081203B
  54. GRB081203A: Swift-XRT refined analysis
  55. GRB 081203B: optical observations
  56. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  57. Swift/UVOT detection of GRB081203B
  58. GRB 081203B: Swift-XRT candidate afterglow.
  59. GRB 081203A: optical observations
  60. Swift UVOT observations of GRB 081203A
  61. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  62. GRB081203A: Swift/UVOT grism redshift
  63. GRB 081203A: Burst detection from Swift-BAT slew data
  64. GRB 081203A: Swift-BAT refined analysis
  65. GRB 081203: Enhanced Swift-XRT position
  66. GRB 081130B: MASTER prompt optical observations
  67. GRB081203: optical observation
  68. GRB 081203: Swift detection of a burst with a bright optical counterpart
  69. GRB 081128: optical observation
  70. GRB 081130B: Fermi GBM detection
  71. GRB 081130: Fermi GBM detection
  72. Swift Trigger 335971: Swift/UVOT Observations
  73. GRB 081126: afterglow photometry
  74. GRB 081126: Fermi GBM detection
  75. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  76. VLA Radio upper limit on GRB 081126
  77. GRB 081129: Fermi GBM detection
  78. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  79. GRB 081128A: optical observations
  80. Swift Trigger 335971 is probably not a real source
  81. Trigger 335971: Swift possible detection of a burst
  82. GRB081128: Swift/UVOT Upper Limits
  83. SGR 1806-20: Fermi GBM detection.
  84. GRB 081122B: Fermi GBM Detection
  85. GRB 081128: Swift-XRT refined analysis
  86. GRB 081128: Liverpool Telescope afterglow confirmation
  87. GRB081128: optical observations
  88. GRB081128 : Lulin optical follow-ups
  89. GRB 081128: Swift-BAT refined analysis
  90. GRB 081128: Enhanced Swift-XRT position
  91. GRB 081128: Optical observation of xinglong TNT
  92. GRB 081128: Swift detection of a burst
  93. GRB 081126: Swift observations continuing
  94. GRB081126: Afterglow photometry from Crni Vrh
  95. GRB 081126: GRT Optical Observation
  96. GRB 081127: Swift/UVOT Upper Limits
  97. GRB 081127: Swift-XRT refined analysis
  98. GRB 081127: Enhanced Swift-XRT position
  99. GRB 081126: Confirmation of the Optical Afterglow
  100. GRB 081127: Swift-BAT refined analysis

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