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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 090926B: VLT spectroscopy
  2. GRB 090927: Swift/UVOT detection of an optical afterglow
  3. GRB 090927: Swift detection of a short burst
  4. GRB 090926B: optical object in error circle
  5. GRB 090926B: MAXI GSC detection
  6. GRB 090926A: VLT/X-shooter redshift
  7. GRB 090926B: NOT optical observation
  8. GRB 090926B: Swift XRT refined analysis
  9. GRB 090926B: Swift-BAT refined analysis
  10. GRB 090926A: Swift/UVOT detection of an optical afterglow
  11. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  12. GRB090926A: UVOT-enhanced XRT position
  13. GRB 090926B: Swift detection of a burst
  14. GRB 090926: Fermi LAT detection
  15. GRB 090926: Fermi GBM detection
  16. GRB 090925: Fermi GBM detection
  17. GRB090904B : IRSF NIR upper limit
  18. GRB090922A: correction to Fermi location
  19. GRB 090922A: Fermi GBM detection
  20. Swift returns to normal operations
  21. GRB 090715B: Skynet/PROMPT Detections
  22. GRB 090726: Skynet/GORT Observations
  23. GRB 090916: Swift-XRT upper limit
  24. GRB 090807: Skynet/DSO Observations
  25. GRB 090915: GROND upper limits
  26. Swift-BAT temporarily off-line for a few days
  27. Short-Duration GRB 090916: Skynet/PROMPT Observations
  28. GRB 090915: SARA detection of afterglow candidate
  29. GRB 090912: optical observation
  30. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  31. GRB 090702: Skynet/GORT Observations
  32. GRB 090902B: Skynet/PROMPT Observations
  33. GRB 090916, Swift-BAT refined analysis
  34. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  35. GRB 090916: Swift detection of a short burst
  36. GRB 090915 Swift-BAT detection of a burst in ground analysis
  37. GRB 090827: Confirmation of the X-ray afterglow
  38. GRB 090912: Swift-XRT refined analysis
  39. GRB 090912, Swift-BAT refined analysis
  40. GRB 090912: Swift/UVOT Upper Limits
  41. GRB 090912 optical upper limit
  42. GRB 090912: Enhanced Swift-XRT position
  43. GRB 090912: Swift detection of a burst
  44. GRB 090910: Fermi GBM detection
  45. GRB 090814A: Skynet/DSO & GORT Observations
  46. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  47. GRB 090904B: GROND detection of the optical afterglow
  48. GRB 090831A: Suzaku WAM observation of the prompt emission
  49. GRB 090904A: Swift/UVOT Refined Analysis
  50. GRB 090904B: Swift/UVOT Refined Analysis
  51. GRB 090902B: Suzaku WAM observation of the prompt emission
  52. GRB 090829A: Suzaku WAM observation of the prompt emission
  53. GRB 090904B: Fermi GBM detection
  54. GRB 090904A: Swift-XRT refined analysis
  55. GRB 090904B: Swift XRT Refined Analysis
  56. GRB 090904B: MOA-II Optical observation
  57. GRB 090904A: Enhanced Swift XRT position
  58. GRB 090904B: Swift-BAT refined analysis
  59. GRB 090902B: VLA radio detection
  60. GRB 090904A: Swift-BAT refined analysis
  61. GRB 090904B: Enhanced Swift-XRT position
  62. GRB090904A: Correction to enhanced XRT position
  63. GRB 090904A: Enhanced Swift-XRT position
  64. GRB 090904A: NOT observations
  65. GRB 090902B: WSRT Radio Observation
  66. GRB090904B: REM observations
  67. GRB 090904B: Swift detection of a burst
  68. GRB 090904A: ROTSE-III Optical Limits
  69. GRB 090904: Swift detection of a burst
  70. GRB 090902B: ROTSE-III Detection of Optical Afterglow
  71. GRB 090902B: Swift/UVOT refined analysis
  72. GRB090902B: Swift XRT refined analysis
  73. GRB 090902B: Faulkes Telescope North observations
  74. GRB 090902B: GROND NIR Afterglow Observations
  75. GRB 090902B: Gemini-N absorption redshift
  76. GRB 090902B: Fermi LAT and GBM refined analysis.
  77. GRB 090902B: Enhanced Swift-XRT position
  78. GRB 090902B: Optical afterglow candidate
  79. GRB090902B: Swift/UVOT observations
  80. GRB 090902B: Swift/XRT Afterglow Candidate
  81. GRB 090902B: Fermi LAT detection
  82. GRB 090902B: Fermi GBM detection of a bright burst
  83. GRB 090902: Fermi GBM detection
  84. GRB 090831A: IPN Triangulation
  85. GRB 090831C BAT refined analysis
  86. GRB 090831C: GROND upper limits
  87. Konus-Wind observations of GRB 090831A
  88. Swift Trigger 361477, called GRB090831B, is probably not real.
  89. GRB090831C: Swift/UVOT upper limits
  90. GRB 090831B: MITSuME optical upper limits
  91. GRB 090831C: Swift XRT Refined Analysis
  92. GRB 090829B: Fermi GBM Detection
  93. GRB 090831C: Enhanced Swift-XRT position
  94. GRB 090831C: Swift detection of a burst
  95. GRB 090831B, RIMOTS optical upper limits
  96. GRB 090831: MAXI GSC detection
  97. GRB 090831B: Swift detection of a possible burst
  98. GRB 090831: Fermi GBM detection
  99. GRB090829: Fermi GBM Detection
  100. Konus-Wind observations of GRB 090827

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