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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 081226: Swift detection of a possible short-hard burst
  2. GRB 080810: optical observations
  3. GRB 081211B: optical observations
  4. GRB081224: LAT retraction
  5. GRB 081224: Swift-XRT observation
  6. GRB 081222: MITSuME optical observation
  7. GRB 081224: Fermi GBM Detection & LAT Localization
  8. GRB 080810: optical observations
  9. Konus-Wind observation of GRB 081222
  10. GRB 081223: Fermi GBM detection
  11. GRB 081221: GROND observations
  12. GRB 081222: Gemini-N confirmation of redshift z=2.77
  13. GRB 081222:Optical afterglow observation
  14. VLA radio upper limit on GRB 081222
  15. GRB 081222: Fermi GBM observation
  16. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  17. GRB 081222: Gemini-South absorption redshift
  18. GRB081222: Swift/UVOT further observations
  19. GRB 081221: Probable host galaxy in Keck imaging
  20. GRB 081204C: Fermi GBM detection
  21. GRB 081222, Swift-BAT refined analysis
  22. GRB 081221, Swift-BAT refined analysis
  23. GRB081222 optical limit by "Pi of the Sky"
  24. Konus-Wind observation of very bright GRB 081215A
  25. GRB 081222: Swift XRT refined analysis
  26. GRB081221: Fermi GBM observation
  27. Swift/UVOT observations of GRB 081221
  28. IPN triangulation of bright GRB 081215A
  29. GRB 081221: Swift-XRT Refined Analysis
  30. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  31. GRB 081222: Faulkes Telescope South observations
  32. GRB 081221: Gemini-N nIR imaging
  33. GRB081222, optical observation
  34. GRB081222: Swift/UVOT detection of an optical afterglow
  35. GRB081203A: BTA observation
  36. Konus-Wind observation of GRB 081221
  37. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  38. GRB081222: REM candidate afterglow
  39. GRB 081222: Swift detection of a burst with a bright optical afterglow
  40. GRB 081221: Enhanced Swift-XRT position
  41. GRB 081221: further NOT observations
  42. GRB 081221: NOT observations
  43. GRB 081221: Swift detection of a burst
  44. GRB 081217: Fermi GBM detection
  45. Modification of Swift/UVOT response to bright GRBs
  46. GRB081215A: Fermi-LAT observations
  47. GRB 081211B: Further Swift-XRT analysis
  48. GRB 081215B: Fermi GBM detection
  49. GRB 081216: Suzaku WAM observation of the prompt emission
  50. GRB 081216 : Fermi GBM observation
  51. GRB 081215A: Fermi GBM detection (correction to event fluence)
  52. GRB 081215A: Fermi GBM detection
  53. IPN localization of short hard GRB 081216
  54. GRB 081211B - possibly a short burst with extended emission
  55. GRB 081118: Zadko observations
  56. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  57. GRB 081215A: Gamma Repeater?
  58. GRB 0811215A: MASTER prompt optical observations
  59. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  60. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  61. Possible GRB 081211B: Swift/UVOT Upper Limits
  62. GRB 081213: Fermi GBM detection
  63. GRB 081210: optical observations
  64. Possible GRB 081211B - Swift-XRT analysis
  65. GRB 081207: Fermi GBM detection
  66. GRB 081209: Fermi GBM detection
  67. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  68. GRB 081007: Detection of a Supernova
  69. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  70. GRB 081210: Xinglong TNT R band Upper Limits
  71. GRB 081210, SMARTS optical/IR observations
  72. GRB 081211: Swift-BAT refined analysis
  73. GRB 081211: Swift XRT refined analysis
  74. GRB 081211: Swift/UVOT detection of an optical afterglow
  75. GRB 081211: Enhanced Swift-XRT position
  76. GRB 081210: Swift/UVOT refined analysis
  77. GRB 081211: Swift detection of a burst
  78. GRB 081210: Swift-XRT refined analysis
  79. GRB081203B: optical observations
  80. GRB 081210: Enhanced Swift-XRT position
  81. GRB 081210: Swift-BAT refined analysis
  82. GRB 081210: Swift detection of a burst with optical afterglow
  83. Konus-Wind observation of GRB 081209
  84. IPN triangulation of short hard GRB 081209
  85. GRB 081203A: optical observations
  86. GRB 081206C: Fermi GBM detection
  87. Radio observation of GRB 081121 with ATCA
  88. Radio observation of GRB 081118 with ATCA
  89. GRB 081206B: Fermi GBM detection
  90. GRB 081206: Fermi GBM detection
  91. GRB 081128: afterglow observations
  92. GRB 081203B: Suzaku WAM observation of the prompt emission
  93. GRB 081203B: Additional Gemini imaging
  94. Radio observation of GRB 081109 with ATCA
  95. Radio observation of GRB 081104 with ATCA
  96. Radio observation of GRB 081029 with ATCA
  97. Radio observation of GRB 081008 with ATCA
  98. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  99. GRB 081203B: Gemini observations
  100. GRB 081128: optical observation in CrAO

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