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

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