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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. GRB081203A: Swift/UVOT grism redshift
  2. GRB 081203A: Burst detection from Swift-BAT slew data
  3. GRB 081203A: Swift-BAT refined analysis
  4. GRB 081203: Enhanced Swift-XRT position
  5. GRB 081130B: MASTER prompt optical observations
  6. GRB081203: optical observation
  7. GRB 081203: Swift detection of a burst with a bright optical counterpart
  8. GRB 081128: optical observation
  9. GRB 081130B: Fermi GBM detection
  10. GRB 081130: Fermi GBM detection
  11. Swift Trigger 335971: Swift/UVOT Observations
  12. GRB 081126: afterglow photometry
  13. GRB 081126: Fermi GBM detection
  14. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  15. VLA Radio upper limit on GRB 081126
  16. GRB 081129: Fermi GBM detection
  17. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  18. GRB 081128A: optical observations
  19. Swift Trigger 335971 is probably not a real source
  20. Trigger 335971: Swift possible detection of a burst
  21. GRB081128: Swift/UVOT Upper Limits
  22. SGR 1806-20: Fermi GBM detection.
  23. GRB 081122B: Fermi GBM Detection
  24. GRB 081128: Swift-XRT refined analysis
  25. GRB 081128: Liverpool Telescope afterglow confirmation
  26. GRB081128: optical observations
  27. GRB081128 : Lulin optical follow-ups
  28. GRB 081128: Swift-BAT refined analysis
  29. GRB 081128: Enhanced Swift-XRT position
  30. GRB 081128: Optical observation of xinglong TNT
  31. GRB 081128: Swift detection of a burst
  32. GRB 081126: Swift observations continuing
  33. GRB081126: Afterglow photometry from Crni Vrh
  34. GRB 081126: GRT Optical Observation
  35. GRB 081127: Swift/UVOT Upper Limits
  36. GRB 081127: Swift-XRT refined analysis
  37. GRB 081127: Enhanced Swift-XRT position
  38. GRB 081126: Confirmation of the Optical Afterglow
  39. GRB 081127: Swift-BAT refined analysis
  40. Konus-Wind observation of GRB 081126
  41. GRB 081126: Swift-XRT refined analysis
  42. GRB 081127: Swift detection of a burst
  43. GRB 081126: Swift/UVOT Observations
  44. GRB 081126: optical observations
  45. GRB 081126: Swift-BAT refined analysis
  46. GRB 081126: Enhanced Swift-XRT position
  47. GRB 081126: TAROT Calern observatory optical observations
  48. GRB 081126: Swift detection of a burst
  49. GRB 081125: Fermi GBM detection
  50. GRB 081124: Fermi GBM detection
  51. GRB 081120: Fermi GBM detection
  52. GRB 081118: Fermi GBM detection.
  53. GRB 081122: Fermi GBM detection
  54. Konus-Wind observation of GRB 081121
  55. GRB 081121, SMARTS optical/IR afterglow observations
  56. GRB081121: Fermi GBM detection
  57. Fermi GBM detection of a weak source
  58. GRB081121: Refined Swift/UVOT observations
  59. GRB 081121: Swift-XRT refined analysis
  60. GRB 081121: Magellan Redshift
  61. GRB 081121: Enhanced Swift-XRT position
  62. GRB 081121: GROND observations
  63. GRB 081121: Swift-BAT refined analysis
  64. GRB081121: Swift/UVOT observations
  65. GRB 081121: Swift detection of a burst
  66. GRB 081121: ROTSE-III Detection of Optical Counterpart
  67. GRB081118 : optical upper limit
  68. GRB 081016b, SMARTS optical/IR observations
  69. GRB 081119: Fermi GBM detection
  70. VLA Radio upper limit on GRB 081118
  71. GRB 081118: VLT redshift
  72. GRB 081118: Swift-XRT refined analysis
  73. GRB 081118: GROND detection of afterglow
  74. GRB 081118: optical afterglow candidate
  75. GRB 081118: Swift UVOT Upper Limits
  76. GRB 081118: Swift-BAT refined analysis
  77. GRB 081118: Enhanced Swift-XRT position
  78. GRB 081118: Swift detection of a burst
  79. GRB 081109A: confirmation of possible detection host galaxy
  80. Further Swift-XRT observations of the probable GRB 081105.
  81. GRB 081113: Fermi GBM detection
  82. GRB 081102: RTT150 Optical observations
  83. GRB 081110: Fermi GBM detection
  84. GRB 081110: MASTER: first optical observations Fermi GRB
  85. GRB 081109: TAROT La Silla observatory optical observations
  86. GRB 081102: MASTER refind and final results
  87. GRB 081109: GROND redshift limit and host extinction
  88. GRB 081025: Swift-XRT further analysis
  89. GRB 081024B: Swift-XRT late-time observations
  90. Swift-BAT refined analysis of trigger 334129
  91. GRB 081109B: Swift/UVOT refined analysis
  92. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  93. GRB 081109A: Possible Swift-UVOT detection
  94. GRB 081109A: Faulkes Telescope South observations
  95. GRB 081109A, Swift-BAT refined analysis
  96. GRB 081109A: Swift-XRT refined analysis
  97. GRB 081109: Fermi GBM detection
  98. GRB 081109: Swift/UVOT upper limits
  99. GRB 081109A optical upper limit
  100. Swift-BAT Trigger 334129: possible burst

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