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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 091024: Faulkes Telescope North Afterglow Candidate
  2. GRB 091024: Swift detection of a burst
  3. GRB 091018: Skynet/PROMPT Continued Observations of Fading
  4. GRB 091020: Additional Lick observations
  5. Konus-Wind observations of GRB 091020 (correction to GCN 10057)
  6. GRB 091020: Lick observations
  7. Konus-Wind observations of GRB 091010
  8. GRB 091020: Swift-XRT refined analysis
  9. GRB 091018: Swift XRT refined analysis
  10. GRB091020 Swift/UVOT observations
  11. GRB 091020: NOT spectroscopic redshift
  12. GRB 091020: MASTER optical transient polarimetry
  13. GRB 091020, Swift-BAT refined analysis
  14. GRB 091020: Enhanced Swift-XRT position
  15. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  16. GRB 091020: Swift detection of a burst with an optical afterglow
  17. GRB 091018: miniTAO/ANIR Observations
  18. GRB 091018: Skynet/PROMPT Observations of Fading
  19. Konus-RF observation of GRB 091018
  20. GRB 091018 : Faulkes Telescope South Observations
  21. GRB 091018: BOOTES-3 observations
  22. GRB 091018: VLT/X-shooter spectra
  23. GRB091018: Swift/UVOT observations
  24. GRB 091018: Swift-BAT refined analysis
  25. GRB 091018: GROND observations
  26. GRB091018: Magellan Echellette Observations
  27. GRB 091018: Enhanced Swift-XRT position
  28. GRB 091018: ROTSE-III Detection of Optical Counterpart
  29. GRB 091015: Skynet/PROMPT Observations
  30. GRB 091018: Swift detection of a burst with optical afterglow
  31. Fwd: GRB 091003: Possible Supernova Component Retraction
  32. GRB 091003: Possible Supernova Component
  33. GRB 091003: Gemini-N redshift of possible host galaxy
  34. GRB 091010: optical obsevation
  35. GRB 091015: RTT150 optical observations
  36. GRB 090726 R band observations
  37. GRB 091010: optical afterglow candidate rejection
  38. GRB 091015: correction to GCN 10025
  39. GRB 090815: a faint long GRB localized by INTEGRAL
  40. GRB 091010: Swift-XRT refined analysis
  41. GRB 091010: Suzaku WAM observation of the prompt emission
  42. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  43. Radio observation of GRB090927 with ATCA
  44. Radio observation of GRB090926a with ATCA
  45. Radio observation of GRB080916c with ATCA
  46. GRB 091010: Fermi GBM observation
  47. GRB 091010: Faulkes Telescope North observations
  48. GRB 090531A: Skynet/PROMPT Observations
  49. GRB 090530A: Skynet/DSO Detections
  50. GRB 091010: RXTE detection
  51. Konus-Wind observations of GRB 091010
  52. GRB 091010: Enhanced XRT position
  53. GRB 091010 optical upper limits
  54. Detection of a short GRB 090929A by RT-2 Experiment
  55. RT-2 observation of the bright GRB 090926A
  56. GRB 091010: GROND afterglow candidate
  57. GRB 091010: Swift/UVOT Upper Limits
  58. GRB 091010: Swift-XRT position
  59. SuperAGILE GRB is 091010 and not 090910
  60. GRB 090910: SuperAGILE Localization of a Long GRB
  61. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  62. GRB 090518: Skynet/PROMPT Observations
  63. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  64. GRB 090904A: afterglow confirmation
  65. GRB 090812: Skynet/PROMPT and GORT Observations
  66. GRB 091003A: Suzaku WAM observation of the prompt emission
  67. GRB 091003: Lick observations and possible SDSS host galaxy
  68. GRB 090926B: Skynet/PROMPT Observations
  69. GRB 091003: WHT ACAM observations
  70. Konus-Wind observation of GRB 091003A
  71. GRB 090929B: Suzaku WAM observation of the prompt emission
  72. GRB 090929A: Suzaku WAM observation of the prompt emission
  73. GRB 091003: Swift-XRT confirmation of fading afterglow
  74. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  75. GRB 091003: Skynet/DSO Observations
  76. GRB 091003: UVOT-enhanced XRT position
  77. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  78. GRB 091003: Swift XRT analysis
  79. GRB 091003A: Fermi LAT detection
  80. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  81. GRB 091003A: Fermi GBM detection
  82. GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
  83. GRB 090929A: Swift/UVOT Observations
  84. GRB 090929A, Swift-BAT refined analysis
  85. GRB 090929B, Swift-BAT refined analysis
  86. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  87. GRB 090929A: Swift-XRT non-detection
  88. Konus-Wind observation of GRB 090929A
  89. Konus-Wind observation of GRB 090929B
  90. GRB 090927: Fermi GBM observation
  91. GRB 090929B: Swift-XRT refined analysis
  92. GRB 090926A: Fermi LAT and GBM refined analysis
  93. GRB 090929B: Gemini-N upper limits
  94. GRB 090929B: Skynet/DSO Observations
  95. GRB 090929B: Swift/UVOT Observations
  96. Konus-RF observation of GRB 090929A
  97. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  98. GRB 090929A BAT location of the Fermi GBM burst
  99. Correction: GRB 090929B: Enhanced Swift-XRT position
  100. GRB 090929: Enhanced Swift-XRT position

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