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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 081211B: optical observations
  2. GRB081224: LAT retraction
  3. GRB 081224: Swift-XRT observation
  4. GRB 081222: MITSuME optical observation
  5. GRB 081224: Fermi GBM Detection & LAT Localization
  6. GRB 080810: optical observations
  7. Konus-Wind observation of GRB 081222
  8. GRB 081223: Fermi GBM detection
  9. GRB 081221: GROND observations
  10. GRB 081222: Gemini-N confirmation of redshift z=2.77
  11. GRB 081222:Optical afterglow observation
  12. VLA radio upper limit on GRB 081222
  13. GRB 081222: Fermi GBM observation
  14. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  15. GRB 081222: Gemini-South absorption redshift
  16. GRB081222: Swift/UVOT further observations
  17. GRB 081221: Probable host galaxy in Keck imaging
  18. GRB 081204C: Fermi GBM detection
  19. GRB 081222, Swift-BAT refined analysis
  20. GRB 081221, Swift-BAT refined analysis
  21. GRB081222 optical limit by "Pi of the Sky"
  22. Konus-Wind observation of very bright GRB 081215A
  23. GRB 081222: Swift XRT refined analysis
  24. GRB081221: Fermi GBM observation
  25. Swift/UVOT observations of GRB 081221
  26. IPN triangulation of bright GRB 081215A
  27. GRB 081221: Swift-XRT Refined Analysis
  28. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  29. GRB 081222: Faulkes Telescope South observations
  30. GRB 081221: Gemini-N nIR imaging
  31. GRB081222, optical observation
  32. GRB081222: Swift/UVOT detection of an optical afterglow
  33. GRB081203A: BTA observation
  34. Konus-Wind observation of GRB 081221
  35. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  36. GRB081222: REM candidate afterglow
  37. GRB 081222: Swift detection of a burst with a bright optical afterglow
  38. GRB 081221: Enhanced Swift-XRT position
  39. GRB 081221: further NOT observations
  40. GRB 081221: NOT observations
  41. GRB 081221: Swift detection of a burst
  42. GRB 081217: Fermi GBM detection
  43. Modification of Swift/UVOT response to bright GRBs
  44. GRB081215A: Fermi-LAT observations
  45. GRB 081211B: Further Swift-XRT analysis
  46. GRB 081215B: Fermi GBM detection
  47. GRB 081216: Suzaku WAM observation of the prompt emission
  48. GRB 081216 : Fermi GBM observation
  49. GRB 081215A: Fermi GBM detection (correction to event fluence)
  50. GRB 081215A: Fermi GBM detection
  51. IPN localization of short hard GRB 081216
  52. GRB 081211B - possibly a short burst with extended emission
  53. GRB 081118: Zadko observations
  54. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  55. GRB 081215A: Gamma Repeater?
  56. GRB 0811215A: MASTER prompt optical observations
  57. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  58. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  59. Possible GRB 081211B: Swift/UVOT Upper Limits
  60. GRB 081213: Fermi GBM detection
  61. GRB 081210: optical observations
  62. Possible GRB 081211B - Swift-XRT analysis
  63. GRB 081207: Fermi GBM detection
  64. GRB 081209: Fermi GBM detection
  65. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  66. GRB 081007: Detection of a Supernova
  67. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  68. GRB 081210: Xinglong TNT R band Upper Limits
  69. GRB 081210, SMARTS optical/IR observations
  70. GRB 081211: Swift-BAT refined analysis
  71. GRB 081211: Swift XRT refined analysis
  72. GRB 081211: Swift/UVOT detection of an optical afterglow
  73. GRB 081211: Enhanced Swift-XRT position
  74. GRB 081210: Swift/UVOT refined analysis
  75. GRB 081211: Swift detection of a burst
  76. GRB 081210: Swift-XRT refined analysis
  77. GRB081203B: optical observations
  78. GRB 081210: Enhanced Swift-XRT position
  79. GRB 081210: Swift-BAT refined analysis
  80. GRB 081210: Swift detection of a burst with optical afterglow
  81. Konus-Wind observation of GRB 081209
  82. IPN triangulation of short hard GRB 081209
  83. GRB 081203A: optical observations
  84. GRB 081206C: Fermi GBM detection
  85. Radio observation of GRB 081121 with ATCA
  86. Radio observation of GRB 081118 with ATCA
  87. GRB 081206B: Fermi GBM detection
  88. GRB 081206: Fermi GBM detection
  89. GRB 081128: afterglow observations
  90. GRB 081203B: Suzaku WAM observation of the prompt emission
  91. GRB 081203B: Additional Gemini imaging
  92. Radio observation of GRB 081109 with ATCA
  93. Radio observation of GRB 081104 with ATCA
  94. Radio observation of GRB 081029 with ATCA
  95. Radio observation of GRB 081008 with ATCA
  96. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  97. GRB 081203B: Gemini observations
  98. GRB 081128: optical observation in CrAO
  99. GRB081203A: Optical observations at Ishigaki
  100. GRB 081128: Optical afterglow observations

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