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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. Fwd: GRB 091003: Possible Supernova Component Retraction
  2. GRB 091003: Possible Supernova Component
  3. GRB 091003: Gemini-N redshift of possible host galaxy
  4. GRB 091010: optical obsevation
  5. GRB 091015: RTT150 optical observations
  6. GRB 090726 R band observations
  7. GRB 091010: optical afterglow candidate rejection
  8. GRB 091015: correction to GCN 10025
  9. GRB 090815: a faint long GRB localized by INTEGRAL
  10. GRB 091010: Swift-XRT refined analysis
  11. GRB 091010: Suzaku WAM observation of the prompt emission
  12. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  13. Radio observation of GRB090927 with ATCA
  14. Radio observation of GRB090926a with ATCA
  15. Radio observation of GRB080916c with ATCA
  16. GRB 091010: Fermi GBM observation
  17. GRB 091010: Faulkes Telescope North observations
  18. GRB 090531A: Skynet/PROMPT Observations
  19. GRB 090530A: Skynet/DSO Detections
  20. GRB 091010: RXTE detection
  21. Konus-Wind observations of GRB 091010
  22. GRB 091010: Enhanced XRT position
  23. GRB 091010 optical upper limits
  24. Detection of a short GRB 090929A by RT-2 Experiment
  25. RT-2 observation of the bright GRB 090926A
  26. GRB 091010: GROND afterglow candidate
  27. GRB 091010: Swift/UVOT Upper Limits
  28. GRB 091010: Swift-XRT position
  29. SuperAGILE GRB is 091010 and not 090910
  30. GRB 090910: SuperAGILE Localization of a Long GRB
  31. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  32. GRB 090518: Skynet/PROMPT Observations
  33. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  34. GRB 090904A: afterglow confirmation
  35. GRB 090812: Skynet/PROMPT and GORT Observations
  36. GRB 091003A: Suzaku WAM observation of the prompt emission
  37. GRB 091003: Lick observations and possible SDSS host galaxy
  38. GRB 090926B: Skynet/PROMPT Observations
  39. GRB 091003: WHT ACAM observations
  40. Konus-Wind observation of GRB 091003A
  41. GRB 090929B: Suzaku WAM observation of the prompt emission
  42. GRB 090929A: Suzaku WAM observation of the prompt emission
  43. GRB 091003: Swift-XRT confirmation of fading afterglow
  44. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  45. GRB 091003: Skynet/DSO Observations
  46. GRB 091003: UVOT-enhanced XRT position
  47. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  48. GRB 091003: Swift XRT analysis
  49. GRB 091003A: Fermi LAT detection
  50. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  51. GRB 091003A: Fermi GBM detection
  52. GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
  53. GRB 090929A: Swift/UVOT Observations
  54. GRB 090929A, Swift-BAT refined analysis
  55. GRB 090929B, Swift-BAT refined analysis
  56. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  57. GRB 090929A: Swift-XRT non-detection
  58. Konus-Wind observation of GRB 090929A
  59. Konus-Wind observation of GRB 090929B
  60. GRB 090927: Fermi GBM observation
  61. GRB 090929B: Swift-XRT refined analysis
  62. GRB 090926A: Fermi LAT and GBM refined analysis
  63. GRB 090929B: Gemini-N upper limits
  64. GRB 090929B: Skynet/DSO Observations
  65. GRB 090929B: Swift/UVOT Observations
  66. Konus-RF observation of GRB 090929A
  67. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  68. GRB 090929A BAT location of the Fermi GBM burst
  69. Correction: GRB 090929B: Enhanced Swift-XRT position
  70. GRB 090929: Enhanced Swift-XRT position
  71. GRB 090929B: Swift detection of a burst
  72. GRB 090929A: Fermi GBM detection
  73. GRB090926A: Swift-XRT refined analysis
  74. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  75. Konus-Wind and Konus-RF observations of GRB 090926A
  76. GRB 090927: VLT redshift
  77. GRB 090926B: Fermi GBM detection
  78. GRB 090927: Zadko Telescope observations
  79. GRB 090927, Swift-BAT refined analysis of the possibly short burst
  80. Swift/UVOT observations of GRB 090927
  81. GRB 090926A: Skynet/PROMPT Continued Observations
  82. GRB 090927: Swift XRT refined analysis
  83. GRB 090926A: Suzaku WAM observation of the prompt emission
  84. GRB 090927: Enhanced Swift-XRT position
  85. GRB090926B: Swift/UVOT Upper Limits
  86. GRB090926A: Swift/UVOT observations
  87. GRB 090926B: VLT spectroscopy
  88. GRB 090927: Swift/UVOT detection of an optical afterglow
  89. GRB 090927: Swift detection of a short burst
  90. GRB 090926B: optical object in error circle
  91. GRB 090926B: MAXI GSC detection
  92. GRB 090926A: VLT/X-shooter redshift
  93. GRB 090926B: NOT optical observation
  94. GRB 090926B: Swift XRT refined analysis
  95. GRB 090926B: Swift-BAT refined analysis
  96. GRB 090926A: Swift/UVOT detection of an optical afterglow
  97. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  98. GRB090926A: UVOT-enhanced XRT position
  99. GRB 090926B: Swift detection of a burst
  100. GRB 090926: Fermi LAT detection

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