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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 081221: Probable host galaxy in Keck imaging
  2. GRB 081204C: Fermi GBM detection
  3. GRB 081222, Swift-BAT refined analysis
  4. GRB 081221, Swift-BAT refined analysis
  5. GRB081222 optical limit by "Pi of the Sky"
  6. Konus-Wind observation of very bright GRB 081215A
  7. GRB 081222: Swift XRT refined analysis
  8. GRB081221: Fermi GBM observation
  9. Swift/UVOT observations of GRB 081221
  10. IPN triangulation of bright GRB 081215A
  11. GRB 081221: Swift-XRT Refined Analysis
  12. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  13. GRB 081222: Faulkes Telescope South observations
  14. GRB 081221: Gemini-N nIR imaging
  15. GRB081222, optical observation
  16. GRB081222: Swift/UVOT detection of an optical afterglow
  17. GRB081203A: BTA observation
  18. Konus-Wind observation of GRB 081221
  19. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  20. GRB081222: REM candidate afterglow
  21. GRB 081222: Swift detection of a burst with a bright optical afterglow
  22. GRB 081221: Enhanced Swift-XRT position
  23. GRB 081221: further NOT observations
  24. GRB 081221: NOT observations
  25. GRB 081221: Swift detection of a burst
  26. GRB 081217: Fermi GBM detection
  27. Modification of Swift/UVOT response to bright GRBs
  28. GRB081215A: Fermi-LAT observations
  29. GRB 081211B: Further Swift-XRT analysis
  30. GRB 081215B: Fermi GBM detection
  31. GRB 081216: Suzaku WAM observation of the prompt emission
  32. GRB 081216 : Fermi GBM observation
  33. GRB 081215A: Fermi GBM detection (correction to event fluence)
  34. GRB 081215A: Fermi GBM detection
  35. IPN localization of short hard GRB 081216
  36. GRB 081211B - possibly a short burst with extended emission
  37. GRB 081118: Zadko observations
  38. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  39. GRB 081215A: Gamma Repeater?
  40. GRB 0811215A: MASTER prompt optical observations
  41. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  42. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  43. Possible GRB 081211B: Swift/UVOT Upper Limits
  44. GRB 081213: Fermi GBM detection
  45. GRB 081210: optical observations
  46. Possible GRB 081211B - Swift-XRT analysis
  47. GRB 081207: Fermi GBM detection
  48. GRB 081209: Fermi GBM detection
  49. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  50. GRB 081007: Detection of a Supernova
  51. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  52. GRB 081210: Xinglong TNT R band Upper Limits
  53. GRB 081210, SMARTS optical/IR observations
  54. GRB 081211: Swift-BAT refined analysis
  55. GRB 081211: Swift XRT refined analysis
  56. GRB 081211: Swift/UVOT detection of an optical afterglow
  57. GRB 081211: Enhanced Swift-XRT position
  58. GRB 081210: Swift/UVOT refined analysis
  59. GRB 081211: Swift detection of a burst
  60. GRB 081210: Swift-XRT refined analysis
  61. GRB081203B: optical observations
  62. GRB 081210: Enhanced Swift-XRT position
  63. GRB 081210: Swift-BAT refined analysis
  64. GRB 081210: Swift detection of a burst with optical afterglow
  65. Konus-Wind observation of GRB 081209
  66. IPN triangulation of short hard GRB 081209
  67. GRB 081203A: optical observations
  68. GRB 081206C: Fermi GBM detection
  69. Radio observation of GRB 081121 with ATCA
  70. Radio observation of GRB 081118 with ATCA
  71. GRB 081206B: Fermi GBM detection
  72. GRB 081206: Fermi GBM detection
  73. GRB 081128: afterglow observations
  74. GRB 081203B: Suzaku WAM observation of the prompt emission
  75. GRB 081203B: Additional Gemini imaging
  76. Radio observation of GRB 081109 with ATCA
  77. Radio observation of GRB 081104 with ATCA
  78. Radio observation of GRB 081029 with ATCA
  79. Radio observation of GRB 081008 with ATCA
  80. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  81. GRB 081203B: Gemini observations
  82. GRB 081128: optical observation in CrAO
  83. GRB081203A: Optical observations at Ishigaki
  84. GRB 081128: Optical afterglow observations
  85. GRB 081204: GROND Observations
  86. GRB081203B: optical observations
  87. Radio detection of GRB 081203B with the VLA
  88. GRB 081204: Magellan observations
  89. GRB081203A: Radio upper limit at 15 GHz
  90. GRB 081204B: Fermi GBM detection
  91. GRB 081204: Swift/UVOT Upper Limits
  92. GRB 081204: Swift XRT afterglow confirmation
  93. GRB081203A: MITSuME optical observation
  94. GRB 081203A: Optical observations of Xinglong TNT telescope
  95. GRB 081203A: Skynet/GORT Detections
  96. GRB 081204: Swift XRT afterglow candidate
  97. GRB081203A: optical observation
  98. GRB 081204 : a long GRB localized by INTEGRAL
  99. VLA Radio upper limit on GRB 081203A
  100. Swift-XRT observations of GRB 081203B

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