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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 081228: Enhanced Swift-XRT position
  2. GRB 081228: TAROT Calern observatory optical observations
  3. GRB 081228: Swift detection of a burst
  4. VLA radio observation of GRB 081221
  5. GRB 081226B: Swift XRT and UVOT upper limits
  6. GRB 081224: Suzaku WAM observation of the prompt emission
  7. GRB 081226: Swift-XRT refined analysis
  8. GRB 081226A: Swift UVOT Upper Limits
  9. GRB 081226: Second epoch of Gemini-South imaging
  10. GRB 081226A: Swift-BAT refined analysis
  11. GRB 081226B: a short-hard GRB detected by INTEGRAL
  12. GRB 081226: Gemini-South spectrum of possible afterglow
  13. GRB 081226: Gemini-South imaging
  14. GRB 081226: GROND afterglow candidate
  15. GRB 081226: ROTSE-III Optical Limits
  16. GRB 081226: Swift detection of a possible short-hard burst
  17. GRB 080810: optical observations
  18. GRB 081211B: optical observations
  19. GRB081224: LAT retraction
  20. GRB 081224: Swift-XRT observation
  21. GRB 081222: MITSuME optical observation
  22. GRB 081224: Fermi GBM Detection & LAT Localization
  23. GRB 080810: optical observations
  24. Konus-Wind observation of GRB 081222
  25. GRB 081223: Fermi GBM detection
  26. GRB 081221: GROND observations
  27. GRB 081222: Gemini-N confirmation of redshift z=2.77
  28. GRB 081222:Optical afterglow observation
  29. VLA radio upper limit on GRB 081222
  30. GRB 081222: Fermi GBM observation
  31. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  32. GRB 081222: Gemini-South absorption redshift
  33. GRB081222: Swift/UVOT further observations
  34. GRB 081221: Probable host galaxy in Keck imaging
  35. GRB 081204C: Fermi GBM detection
  36. GRB 081222, Swift-BAT refined analysis
  37. GRB 081221, Swift-BAT refined analysis
  38. GRB081222 optical limit by "Pi of the Sky"
  39. Konus-Wind observation of very bright GRB 081215A
  40. GRB 081222: Swift XRT refined analysis
  41. GRB081221: Fermi GBM observation
  42. Swift/UVOT observations of GRB 081221
  43. IPN triangulation of bright GRB 081215A
  44. GRB 081221: Swift-XRT Refined Analysis
  45. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  46. GRB 081222: Faulkes Telescope South observations
  47. GRB 081221: Gemini-N nIR imaging
  48. GRB081222, optical observation
  49. GRB081222: Swift/UVOT detection of an optical afterglow
  50. GRB081203A: BTA observation
  51. Konus-Wind observation of GRB 081221
  52. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  53. GRB081222: REM candidate afterglow
  54. GRB 081222: Swift detection of a burst with a bright optical afterglow
  55. GRB 081221: Enhanced Swift-XRT position
  56. GRB 081221: further NOT observations
  57. GRB 081221: NOT observations
  58. GRB 081221: Swift detection of a burst
  59. GRB 081217: Fermi GBM detection
  60. Modification of Swift/UVOT response to bright GRBs
  61. GRB081215A: Fermi-LAT observations
  62. GRB 081211B: Further Swift-XRT analysis
  63. GRB 081215B: Fermi GBM detection
  64. GRB 081216: Suzaku WAM observation of the prompt emission
  65. GRB 081216 : Fermi GBM observation
  66. GRB 081215A: Fermi GBM detection (correction to event fluence)
  67. GRB 081215A: Fermi GBM detection
  68. IPN localization of short hard GRB 081216
  69. GRB 081211B - possibly a short burst with extended emission
  70. GRB 081118: Zadko observations
  71. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  72. GRB 081215A: Gamma Repeater?
  73. GRB 0811215A: MASTER prompt optical observations
  74. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  75. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  76. Possible GRB 081211B: Swift/UVOT Upper Limits
  77. GRB 081213: Fermi GBM detection
  78. GRB 081210: optical observations
  79. Possible GRB 081211B - Swift-XRT analysis
  80. GRB 081207: Fermi GBM detection
  81. GRB 081209: Fermi GBM detection
  82. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  83. GRB 081007: Detection of a Supernova
  84. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  85. GRB 081210: Xinglong TNT R band Upper Limits
  86. GRB 081210, SMARTS optical/IR observations
  87. GRB 081211: Swift-BAT refined analysis
  88. GRB 081211: Swift XRT refined analysis
  89. GRB 081211: Swift/UVOT detection of an optical afterglow
  90. GRB 081211: Enhanced Swift-XRT position
  91. GRB 081210: Swift/UVOT refined analysis
  92. GRB 081211: Swift detection of a burst
  93. GRB 081210: Swift-XRT refined analysis
  94. GRB081203B: optical observations
  95. GRB 081210: Enhanced Swift-XRT position
  96. GRB 081210: Swift-BAT refined analysis
  97. GRB 081210: Swift detection of a burst with optical afterglow
  98. Konus-Wind observation of GRB 081209
  99. IPN triangulation of short hard GRB 081209
  100. GRB 081203A: optical observations

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