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

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