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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"

28086 results found.

  1. GRB 091117A: Swift/UVOT followup observations
  2. GRB 091117: VLA radio observations
  3. GRB 091117: Swift-XRT observations
  4. GRB 091117 BAT refined analysis
  5. GRB 091117: Evidence for Variability of XRT Source #1
  6. GRB091117: Gemini South Observations
  7. GRB 091117: Swift XRT refined analysis
  8. GRB 091112: Suzaku WAM observation of the prompt emission
  9. GRB 091102A: Suzaku WAM observation of the prompt emission
  10. GRB 091109B: Suzaku WAM observation of the prompt emission
  11. GRB091111: Swift XRT refined analysis
  12. GRB 091112: Swift-BAT refined analysis
  13. GRB 091031: Fermi LAT detection of a faint burst
  14. GRB 091111: BOOTES-3 contemporaneous imaging
  15. GRB 091111: BOOTES-3 observations
  16. GRB 091109A: GROND and VLT observations
  17. GRB 091109B: Swift/UVOT Upper Limits
  18. GRB 091109B: Swift-XRT Team refined analysis
  19. GRB 091109B: Swift-BAT refined analysis
  20. GRB 091109B: Enhanced Swift-XRT position
  21. GRB 091109B: Optical limits from Watcher
  22. GRB 091109B: ROTSE-III Optical Limits
  23. GRB 091109B: Swift detection of a short burst
  24. GRB 091030: Fermi GBM detection
  25. GRB 091109: Swift-XRT refined analysis
  26. GRB 091109: BOOTES-3 observations
  27. GRB 091109: Swift/UVOT observations
  28. GRB 091109: Faulkes Telescope South observations
  29. GRB 091109: Swift-BAT refined analysis
  30. GRB 091109: Enhanced Swift-XRT position
  31. GRB091109: REM detection of the NIR afterglow
  32. GRB 091109: Swift detection of a burst with optical afterglow
  33. GRB 091029: Observations from Stardome Observatory
  34. GRB 091104: Swift-BAT refined analysis
  35. GRB 091104: Swift XRT Refined Analysis
  36. GRB 091104: Swift/UVOT Upper Limits
  37. GRB 091104: Enhanced Swift-XRT position
  38. GRB 091104: Swift detection of a burst
  39. GRB 091102: LABOCA/APEX submm observations
  40. Fermi LAT Upper Limits on GRB 091010
  41. GRB 091102 : Faulkes Telescope South Upper Limits
  42. GRB 091102: Swift-XRT refined analysis
  43. GRB 091102: Swift/UVOT Upper Limits
  44. GRB 091102: GROND Upper Limits
  45. GRB 091102: BOOTES-3 observations
  46. GRB 091102: Swift-BAT refined analysis
  47. GRB 091102: Swift/XRT localization
  48. GRB 091024: optical observations
  49. GRB 091031: Fermi GBM detection
  50. GRB 091024: Fermi LAT upper limits
  51. GRB 091018, SMARTS optical/IR afterglow observations
  52. GRB 090920: Skynet/DSO Detection
  53. GRB091029: Swift/UVOT observations
  54. GRB 091029: Swift XRT refined analysis
  55. GRB 091029: Swift-BAT refined analysis
  56. GRB 091029: Enhanced Swift-XRT position
  57. GRB091024 optical observations
  58. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  59. GRB 091029: Swift detection of a burst with an optical counterpart
  60. GRB 091020: Fermi GBM observation
  61. GRB 091026: Suzaku WAM observation of the prompt emission
  62. GRB 091026: GROND Upper Limits
  63. GRB 091026: Swift-BAT refined analysis
  64. Radio afterglow detection from GRB 091020
  65. GRB 091026: Swift/UVOT Upper Limits
  66. GRB 091026: Swift-XRT refined analysis
  67. GRB 091026: Enhanced Swift-XRT position
  68. Konus-Wind and Konus-RF observations of GRB 091024
  69. GRB 091026: Swift detection of a Gamma Ray Burst
  70. GRB091024 Swift/UVOT Upper Limits
  71. GRB 091024: Super-LOTIS early observations
  72. GRB 091024: Swift-BAT refined analysis
  73. GRB 091024: Fermi GBM Observations
  74. GRB 091024: Swift-XRT team refined analysis
  75. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  76. GRB 091024: GRAS004 optical observations
  77. GRB 091020: Swift-XRT refined analysis
  78. GRB 091018: Swift XRT refined analysis
  79. GRB091020 Swift/UVOT observations
  80. GRB 091020, Swift-BAT refined analysis
  81. GRB 091020: Enhanced Swift-XRT position
  82. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  83. GRB 091020: Swift detection of a burst with an optical afterglow
  84. GRB 091018: Skynet/PROMPT Observations of Fading
  85. Konus-RF observation of GRB 091018
  86. GRB 091018 : Faulkes Telescope South Observations
  87. GRB091018: Swift/UVOT observations
  88. GRB 091018: Swift-BAT refined analysis
  89. GRB 091018: Enhanced Swift-XRT position
  90. GRB 091018: ROTSE-III Detection of Optical Counterpart
  91. GRB 091015: Skynet/PROMPT Observations
  92. GRB 091018: Swift detection of a burst with optical afterglow
  93. GRB 091010: optical obsevation
  94. GRB 090726 R band observations
  95. GRB 091010: optical afterglow candidate rejection
  96. GRB 091010: Swift-XRT refined analysis
  97. GRB 091010: Suzaku WAM observation of the prompt emission
  98. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  99. Radio observation of GRB090927 with ATCA
  100. Radio observation of GRB090926a with ATCA

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