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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 081207: Fermi GBM detection
  2. GRB 081209: Fermi GBM detection
  3. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  4. GRB 081007: Detection of a Supernova
  5. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  6. GRB 081210: Xinglong TNT R band Upper Limits
  7. GRB 081210, SMARTS optical/IR observations
  8. GRB 081211: Swift-BAT refined analysis
  9. GRB 081211: Swift XRT refined analysis
  10. GRB 081211: Swift/UVOT detection of an optical afterglow
  11. GRB 081211: Enhanced Swift-XRT position
  12. GRB 081210: Swift/UVOT refined analysis
  13. GRB 081211: Swift detection of a burst
  14. GRB 081210: Swift-XRT refined analysis
  15. GRB081203B: optical observations
  16. GRB 081210: Enhanced Swift-XRT position
  17. GRB 081210: Swift-BAT refined analysis
  18. GRB 081210: Swift detection of a burst with optical afterglow
  19. Konus-Wind observation of GRB 081209
  20. IPN triangulation of short hard GRB 081209
  21. GRB 081203A: optical observations
  22. GRB 081206C: Fermi GBM detection
  23. Radio observation of GRB 081121 with ATCA
  24. Radio observation of GRB 081118 with ATCA
  25. GRB 081206B: Fermi GBM detection
  26. GRB 081206: Fermi GBM detection
  27. GRB 081128: afterglow observations
  28. GRB 081203B: Suzaku WAM observation of the prompt emission
  29. GRB 081203B: Additional Gemini imaging
  30. Radio observation of GRB 081109 with ATCA
  31. Radio observation of GRB 081104 with ATCA
  32. Radio observation of GRB 081029 with ATCA
  33. Radio observation of GRB 081008 with ATCA
  34. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  35. GRB 081203B: Gemini observations
  36. GRB 081128: optical observation in CrAO
  37. GRB081203A: Optical observations at Ishigaki
  38. GRB 081128: Optical afterglow observations
  39. GRB 081204: GROND Observations
  40. GRB081203B: optical observations
  41. Radio detection of GRB 081203B with the VLA
  42. GRB 081204: Magellan observations
  43. GRB081203A: Radio upper limit at 15 GHz
  44. GRB 081204B: Fermi GBM detection
  45. GRB 081204: Swift/UVOT Upper Limits
  46. GRB 081204: Swift XRT afterglow confirmation
  47. GRB081203A: MITSuME optical observation
  48. GRB 081203A: Optical observations of Xinglong TNT telescope
  49. GRB 081203A: Skynet/GORT Detections
  50. GRB 081204: Swift XRT afterglow candidate
  51. GRB081203A: optical observation
  52. GRB 081204 : a long GRB localized by INTEGRAL
  53. VLA Radio upper limit on GRB 081203A
  54. Swift-XRT observations of GRB 081203B
  55. Konus-Wind observation of GRB 081203A
  56. Konus-Wind observation of GRB 081203B
  57. GRB081203A: Swift-XRT refined analysis
  58. GRB 081203B: optical observations
  59. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  60. Swift/UVOT detection of GRB081203B
  61. GRB 081203B: Swift-XRT candidate afterglow.
  62. GRB 081203A: optical observations
  63. Swift UVOT observations of GRB 081203A
  64. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  65. GRB081203A: Swift/UVOT grism redshift
  66. GRB 081203A: Burst detection from Swift-BAT slew data
  67. GRB 081203A: Swift-BAT refined analysis
  68. GRB 081203: Enhanced Swift-XRT position
  69. GRB 081130B: MASTER prompt optical observations
  70. GRB081203: optical observation
  71. GRB 081203: Swift detection of a burst with a bright optical counterpart
  72. GRB 081128: optical observation
  73. GRB 081130B: Fermi GBM detection
  74. GRB 081130: Fermi GBM detection
  75. Swift Trigger 335971: Swift/UVOT Observations
  76. GRB 081126: afterglow photometry
  77. GRB 081126: Fermi GBM detection
  78. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  79. VLA Radio upper limit on GRB 081126
  80. GRB 081129: Fermi GBM detection
  81. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  82. GRB 081128A: optical observations
  83. Swift Trigger 335971 is probably not a real source
  84. Trigger 335971: Swift possible detection of a burst
  85. GRB081128: Swift/UVOT Upper Limits
  86. SGR 1806-20: Fermi GBM detection.
  87. GRB 081122B: Fermi GBM Detection
  88. GRB 081128: Swift-XRT refined analysis
  89. GRB 081128: Liverpool Telescope afterglow confirmation
  90. GRB081128: optical observations
  91. GRB081128 : Lulin optical follow-ups
  92. GRB 081128: Swift-BAT refined analysis
  93. GRB 081128: Enhanced Swift-XRT position
  94. GRB 081128: Optical observation of xinglong TNT
  95. GRB 081128: Swift detection of a burst
  96. GRB 081126: Swift observations continuing
  97. GRB081126: Afterglow photometry from Crni Vrh
  98. GRB 081126: GRT Optical Observation
  99. GRB 081127: Swift/UVOT Upper Limits
  100. GRB 081127: Swift-XRT refined analysis

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