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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"

19592 results found.

  1. GRB 091029: Skynet/PROMPT Observations of Peak and Fading
  2. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  3. GRB 091029: Swift detection of a burst with an optical counterpart
  4. A mistake in testing a new function in Swift
  5. GRB 091020: Fermi GBM observation
  6. GRB 091026: Suzaku WAM observation of the prompt emission
  7. GRB 091026: GROND Upper Limits
  8. GRB 091020: Late TLS detection
  9. GRB 091026: Swift-BAT refined analysis
  10. Radio afterglow detection from GRB 091020
  11. GRB 091026: Swift/UVOT Upper Limits
  12. GRB 091024: Burst was outside the Swift-BAT FOV after T0(BAT)+460sec
  13. GRB 091026: Swift-XRT refined analysis
  14. GRB 091026: Enhanced Swift-XRT position
  15. Konus-Wind and Konus-RF observations of GRB 091024
  16. GRB 091026: Updated Swift-XRT position
  17. GRB 091026: Swift detection of a Gamma Ray Burst
  18. Swift-BAT Triggers 373776-373778 are not real
  19. GRB091024 Swift/UVOT Upper Limits
  20. GRB 091024: TLS Upper Limit
  21. GRB 091020: Early TLS Multicolor detections, red afterglow
  22. GRB 091024: KAIT optical afterglow observations
  23. GRB 091024: Swift-BAT refined analysis
  24. Swift-BAT Triggers 373679-373684 are not real
  25. GRB 091024: Fermi GBM Observations
  26. GRB 091024: Swift-XRT team refined analysis
  27. Swift-BAT trigger 373691 is a galactic bulge transient
  28. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  29. GRB 091024: Faulkes Telescope North Afterglow Candidate
  30. GRB 091024: Swift detection of a burst
  31. GRB 091020: Swift-XRT refined analysis
  32. GRB 091018: Swift XRT refined analysis
  33. GRB091020 Swift/UVOT observations
  34. GRB 091020, Swift-BAT refined analysis
  35. GRB 091020: Enhanced Swift-XRT position
  36. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  37. GRB 091020: Swift detection of a burst with an optical afterglow
  38. GRB 091018: Skynet/PROMPT Observations of Fading
  39. Konus-RF observation of GRB 091018
  40. GRB 091018 : Faulkes Telescope South Observations
  41. GRB091018: Swift/UVOT observations
  42. GRB 091018: Swift-BAT refined analysis
  43. GRB 091018: Enhanced Swift-XRT position
  44. GRB 091018: ROTSE-III Detection of Optical Counterpart
  45. GRB 091018: Swift detection of a burst with optical afterglow
  46. GRB 090726 R band observations
  47. GRB 091010: Swift-XRT refined analysis
  48. Radio observation of GRB090927 with ATCA
  49. GRB 091010: Fermi GBM observation
  50. GRB 090531A: Skynet/PROMPT Observations
  51. GRB 090530A: Skynet/DSO Detections
  52. GRB 091010: Enhanced XRT position
  53. GRB 091010: GROND afterglow candidate
  54. GRB 091010: Swift/UVOT Upper Limits
  55. GRB 091010: Swift-XRT position
  56. GRB 090518: Skynet/PROMPT Observations
  57. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  58. GRB 090812: Skynet/PROMPT and GORT Observations
  59. GRB 091003: Lick observations and possible SDSS host galaxy
  60. GRB 090926B: Skynet/PROMPT Observations
  61. GRB 090929B: Suzaku WAM observation of the prompt emission
  62. GRB 091003: Swift-XRT confirmation of fading afterglow
  63. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  64. GRB 091003: UVOT-enhanced XRT position
  65. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  66. GRB 091003: Swift XRT analysis
  67. GRB 091003A: Fermi LAT detection
  68. GRB 090929A: Swift/UVOT Observations
  69. GRB 090929A, Swift-BAT refined analysis
  70. GRB 090929B, Swift-BAT refined analysis
  71. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  72. GRB 090929A: Swift-XRT non-detection
  73. Konus-Wind observation of GRB 090929A
  74. Konus-Wind observation of GRB 090929B
  75. GRB 090927: Fermi GBM observation
  76. GRB 090929B: Swift-XRT refined analysis
  77. GRB 090929B: Skynet/DSO Observations
  78. GRB 090929B: Swift/UVOT Observations
  79. Konus-RF observation of GRB 090929A
  80. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  81. GRB 090929A BAT location of the Fermi GBM burst
  82. Correction: GRB 090929B: Enhanced Swift-XRT position
  83. GRB 090929: Enhanced Swift-XRT position
  84. GRB 090929B: Swift detection of a burst
  85. GRB090926A: Swift-XRT refined analysis
  86. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  87. GRB 090926B: Fermi GBM detection
  88. GRB 090927: Zadko Telescope observations
  89. GRB 090927, Swift-BAT refined analysis of the possibly short burst
  90. Swift/UVOT observations of GRB 090927
  91. GRB 090927: Swift XRT refined analysis
  92. GRB 090927: Enhanced Swift-XRT position
  93. GRB090926B: Swift/UVOT Upper Limits
  94. GRB090926A: Swift/UVOT observations
  95. GRB 090927: Swift/UVOT detection of an optical afterglow
  96. GRB 090927: Swift detection of a short burst
  97. GRB 090926B: MAXI GSC detection
  98. GRB 090926B: Swift XRT refined analysis
  99. GRB 090926B: Swift-BAT refined analysis
  100. GRB 090926A: Swift/UVOT detection of an optical afterglow

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