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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 081222: Faulkes Telescope South observations
  2. GRB 081221: Gemini-N nIR imaging
  3. GRB081222, optical observation
  4. GRB081222: Swift/UVOT detection of an optical afterglow
  5. GRB081203A: BTA observation
  6. Konus-Wind observation of GRB 081221
  7. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  8. GRB081222: REM candidate afterglow
  9. GRB 081222: Swift detection of a burst with a bright optical afterglow
  10. GRB 081221: Enhanced Swift-XRT position
  11. GRB 081221: further NOT observations
  12. GRB 081221: NOT observations
  13. GRB 081221: Swift detection of a burst
  14. GRB 081217: Fermi GBM detection
  15. Modification of Swift/UVOT response to bright GRBs
  16. GRB081215A: Fermi-LAT observations
  17. GRB 081211B: Further Swift-XRT analysis
  18. GRB 081215B: Fermi GBM detection
  19. GRB 081216: Suzaku WAM observation of the prompt emission
  20. GRB 081216 : Fermi GBM observation
  21. GRB 081215A: Fermi GBM detection (correction to event fluence)
  22. GRB 081215A: Fermi GBM detection
  23. IPN localization of short hard GRB 081216
  24. GRB 081211B - possibly a short burst with extended emission
  25. GRB 081118: Zadko observations
  26. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  27. GRB 081215A: Gamma Repeater?
  28. GRB 0811215A: MASTER prompt optical observations
  29. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  30. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  31. Possible GRB 081211B: Swift/UVOT Upper Limits
  32. GRB 081213: Fermi GBM detection
  33. GRB 081210: optical observations
  34. Possible GRB 081211B - Swift-XRT analysis
  35. GRB 081207: Fermi GBM detection
  36. GRB 081209: Fermi GBM detection
  37. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  38. GRB 081007: Detection of a Supernova
  39. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  40. GRB 081210: Xinglong TNT R band Upper Limits
  41. GRB 081210, SMARTS optical/IR observations
  42. GRB 081211: Swift-BAT refined analysis
  43. GRB 081211: Swift XRT refined analysis
  44. GRB 081211: Swift/UVOT detection of an optical afterglow
  45. GRB 081211: Enhanced Swift-XRT position
  46. GRB 081210: Swift/UVOT refined analysis
  47. GRB 081211: Swift detection of a burst
  48. GRB 081210: Swift-XRT refined analysis
  49. GRB081203B: optical observations
  50. GRB 081210: Enhanced Swift-XRT position
  51. GRB 081210: Swift-BAT refined analysis
  52. GRB 081210: Swift detection of a burst with optical afterglow
  53. Konus-Wind observation of GRB 081209
  54. IPN triangulation of short hard GRB 081209
  55. GRB 081203A: optical observations
  56. GRB 081206C: Fermi GBM detection
  57. Radio observation of GRB 081121 with ATCA
  58. Radio observation of GRB 081118 with ATCA
  59. GRB 081206B: Fermi GBM detection
  60. GRB 081206: Fermi GBM detection
  61. GRB 081128: afterglow observations
  62. GRB 081203B: Suzaku WAM observation of the prompt emission
  63. GRB 081203B: Additional Gemini imaging
  64. Radio observation of GRB 081109 with ATCA
  65. Radio observation of GRB 081104 with ATCA
  66. Radio observation of GRB 081029 with ATCA
  67. Radio observation of GRB 081008 with ATCA
  68. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  69. GRB 081203B: Gemini observations
  70. GRB 081128: optical observation in CrAO
  71. GRB081203A: Optical observations at Ishigaki
  72. GRB 081128: Optical afterglow observations
  73. GRB 081204: GROND Observations
  74. GRB081203B: optical observations
  75. Radio detection of GRB 081203B with the VLA
  76. GRB 081204: Magellan observations
  77. GRB081203A: Radio upper limit at 15 GHz
  78. GRB 081204B: Fermi GBM detection
  79. GRB 081204: Swift/UVOT Upper Limits
  80. GRB 081204: Swift XRT afterglow confirmation
  81. GRB081203A: MITSuME optical observation
  82. GRB 081203A: Optical observations of Xinglong TNT telescope
  83. GRB 081203A: Skynet/GORT Detections
  84. GRB 081204: Swift XRT afterglow candidate
  85. GRB081203A: optical observation
  86. GRB 081204 : a long GRB localized by INTEGRAL
  87. VLA Radio upper limit on GRB 081203A
  88. Swift-XRT observations of GRB 081203B
  89. Konus-Wind observation of GRB 081203A
  90. Konus-Wind observation of GRB 081203B
  91. GRB081203A: Swift-XRT refined analysis
  92. GRB 081203B: optical observations
  93. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  94. Swift/UVOT detection of GRB081203B
  95. GRB 081203B: Swift-XRT candidate afterglow.
  96. GRB 081203A: optical observations
  97. Swift UVOT observations of GRB 081203A
  98. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  99. GRB081203A: Swift/UVOT grism redshift
  100. GRB 081203A: Burst detection from Swift-BAT slew data

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