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

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