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

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