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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"

28056 results found.

  1. GRB091109: REM detection of the NIR afterglow
  2. GRB 091109: Swift detection of a burst with optical afterglow
  3. GRB 091029: Observations from Stardome Observatory
  4. GRB 091104: Swift-BAT refined analysis
  5. GRB 091104: Swift XRT Refined Analysis
  6. GRB 091104: Swift/UVOT Upper Limits
  7. GRB 091104: Enhanced Swift-XRT position
  8. GRB 091104: Swift detection of a burst
  9. GRB 091102: LABOCA/APEX submm observations
  10. Fermi LAT Upper Limits on GRB 091010
  11. GRB 091102 : Faulkes Telescope South Upper Limits
  12. GRB 091102: Swift-XRT refined analysis
  13. GRB 091102: Swift/UVOT Upper Limits
  14. GRB 091102: GROND Upper Limits
  15. GRB 091102: BOOTES-3 observations
  16. GRB 091102: Swift-BAT refined analysis
  17. GRB 091102: Swift/XRT localization
  18. GRB 091024: optical observations
  19. GRB 091031: Fermi GBM detection
  20. GRB 091024: Fermi LAT upper limits
  21. GRB 091018, SMARTS optical/IR afterglow observations
  22. GRB 090920: Skynet/DSO Detection
  23. GRB091029: Swift/UVOT observations
  24. GRB 091029: Swift XRT refined analysis
  25. GRB 091029: Swift-BAT refined analysis
  26. GRB 091029: Enhanced Swift-XRT position
  27. GRB091024 optical observations
  28. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  29. GRB 091029: Swift detection of a burst with an optical counterpart
  30. GRB 091020: Fermi GBM observation
  31. GRB 091026: Suzaku WAM observation of the prompt emission
  32. GRB 091026: GROND Upper Limits
  33. GRB 091026: Swift-BAT refined analysis
  34. Radio afterglow detection from GRB 091020
  35. GRB 091026: Swift/UVOT Upper Limits
  36. GRB 091026: Swift-XRT refined analysis
  37. GRB 091026: Enhanced Swift-XRT position
  38. Konus-Wind and Konus-RF observations of GRB 091024
  39. GRB 091026: Swift detection of a Gamma Ray Burst
  40. GRB091024 Swift/UVOT Upper Limits
  41. GRB 091024: Super-LOTIS early observations
  42. GRB 091024: Swift-BAT refined analysis
  43. GRB 091024: Fermi GBM Observations
  44. GRB 091024: Swift-XRT team refined analysis
  45. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  46. GRB 091024: GRAS004 optical observations
  47. GRB 091020: Swift-XRT refined analysis
  48. GRB 091018: Swift XRT refined analysis
  49. GRB091020 Swift/UVOT observations
  50. GRB 091020, Swift-BAT refined analysis
  51. GRB 091020: Enhanced Swift-XRT position
  52. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  53. GRB 091020: Swift detection of a burst with an optical afterglow
  54. GRB 091018: Skynet/PROMPT Observations of Fading
  55. Konus-RF observation of GRB 091018
  56. GRB 091018 : Faulkes Telescope South Observations
  57. GRB091018: Swift/UVOT observations
  58. GRB 091018: Swift-BAT refined analysis
  59. GRB 091018: Enhanced Swift-XRT position
  60. GRB 091018: ROTSE-III Detection of Optical Counterpart
  61. GRB 091015: Skynet/PROMPT Observations
  62. GRB 091018: Swift detection of a burst with optical afterglow
  63. GRB 091010: optical obsevation
  64. GRB 090726 R band observations
  65. GRB 091010: optical afterglow candidate rejection
  66. GRB 091010: Swift-XRT refined analysis
  67. GRB 091010: Suzaku WAM observation of the prompt emission
  68. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  69. Radio observation of GRB090927 with ATCA
  70. Radio observation of GRB090926a with ATCA
  71. Radio observation of GRB080916c with ATCA
  72. GRB 091010: Fermi GBM observation
  73. GRB 091010: Faulkes Telescope North observations
  74. GRB 090531A: Skynet/PROMPT Observations
  75. GRB 090530A: Skynet/DSO Detections
  76. GRB 091010: Enhanced XRT position
  77. GRB 091010 optical upper limits
  78. Detection of a short GRB 090929A by RT-2 Experiment
  79. GRB 091010: GROND afterglow candidate
  80. GRB 091010: Swift/UVOT Upper Limits
  81. GRB 091010: Swift-XRT position
  82. GRB 090910: SuperAGILE Localization of a Long GRB
  83. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  84. GRB 090518: Skynet/PROMPT Observations
  85. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  86. GRB 090904A: afterglow confirmation
  87. GRB 090812: Skynet/PROMPT and GORT Observations
  88. GRB 091003A: Suzaku WAM observation of the prompt emission
  89. GRB 090926B: Skynet/PROMPT Observations
  90. GRB 091003: WHT ACAM observations
  91. GRB 090929B: Suzaku WAM observation of the prompt emission
  92. GRB 090929A: Suzaku WAM observation of the prompt emission
  93. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  94. GRB 091003: Skynet/DSO Observations
  95. GRB 091003: UVOT-enhanced XRT position
  96. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  97. GRB 091003A: Fermi LAT detection
  98. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  99. GRB 091003A: Fermi GBM detection
  100. GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading

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