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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"

23404 results found.

  1. GRB 090531A: Skynet/PROMPT Observations
  2. GRB 091010: Enhanced XRT position
  3. GRB 091010 optical upper limits
  4. GRB 091010: GROND afterglow candidate
  5. GRB 091010: Swift/UVOT Upper Limits
  6. GRB 090910: SuperAGILE Localization of a Long GRB
  7. GRB 090518: Skynet/PROMPT Observations
  8. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  9. GRB 090904A: afterglow confirmation
  10. GRB 090812: Skynet/PROMPT and GORT Observations
  11. GRB 091003A: Suzaku WAM observation of the prompt emission
  12. GRB 090926B: Skynet/PROMPT Observations
  13. GRB 091003: WHT ACAM observations
  14. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  15. GRB 091003: Skynet/DSO Observations
  16. GRB 091003: UVOT-enhanced XRT position
  17. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  18. GRB 091003: Swift XRT analysis
  19. GRB 091003A: Fermi LAT detection
  20. GRB 091003A: Fermi GBM detection
  21. GRB 090929A: Swift/UVOT Observations
  22. GRB 090929A, Swift-BAT refined analysis
  23. GRB 090929B, Swift-BAT refined analysis
  24. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  25. GRB 090929A: Swift-XRT non-detection
  26. Konus-Wind observation of GRB 090929A
  27. GRB 090929B: Gemini-N upper limits
  28. GRB 090929B: Skynet/DSO Observations
  29. GRB 090929B: Swift/UVOT Observations
  30. Konus-RF observation of GRB 090929A
  31. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  32. GRB 090929A BAT location of the Fermi GBM burst
  33. Correction: GRB 090929B: Enhanced Swift-XRT position
  34. GRB 090929: Enhanced Swift-XRT position
  35. GRB 090929B: Swift detection of a burst
  36. GRB 090929A: Fermi GBM detection
  37. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  38. GRB 090927: Zadko Telescope observations
  39. Swift/UVOT observations of GRB 090927
  40. GRB 090927: Swift XRT refined analysis
  41. GRB 090927: Enhanced Swift-XRT position
  42. GRB090926B: Swift/UVOT Upper Limits
  43. GRB090926A: Swift/UVOT observations
  44. GRB 090926B: VLT spectroscopy
  45. GRB 090927: Swift detection of a short burst
  46. GRB 090926B: optical object in error circle
  47. GRB 090926B: MAXI GSC detection
  48. GRB 090926B: NOT optical observation
  49. GRB 090926B: Swift XRT refined analysis
  50. GRB 090926A: Swift/UVOT detection of an optical afterglow
  51. GRB090926A: UVOT-enhanced XRT position
  52. GRB 090926B: Swift detection of a burst
  53. GRB 090926: Fermi LAT detection
  54. GRB 090926: Fermi GBM detection
  55. GRB 090925: Fermi GBM detection
  56. GRB090922A: correction to Fermi location
  57. GRB 090922A: Fermi GBM detection
  58. GRB 090715B: Skynet/PROMPT Detections
  59. GRB 090726: Skynet/GORT Observations
  60. GRB 090916: Swift-XRT upper limit
  61. GRB 090807: Skynet/DSO Observations
  62. GRB 090915: GROND upper limits
  63. Short-Duration GRB 090916: Skynet/PROMPT Observations
  64. GRB 090915: SARA detection of afterglow candidate
  65. GRB 090912: optical observation
  66. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  67. GRB 090702: Skynet/GORT Observations
  68. GRB 090902B: Skynet/PROMPT Observations
  69. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  70. GRB 090916: Swift detection of a short burst
  71. GRB 090915 Swift-BAT detection of a burst in ground analysis
  72. GRB 090827: Confirmation of the X-ray afterglow
  73. GRB 090912: Swift/UVOT Upper Limits
  74. GRB 090912 optical upper limit
  75. GRB 090912: Enhanced Swift-XRT position
  76. GRB 090912: Swift detection of a burst
  77. GRB 090910: Fermi GBM detection
  78. GRB 090814A: Skynet/DSO & GORT Observations
  79. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  80. GRB 090904B: GROND detection of the optical afterglow
  81. GRB 090904A: Swift/UVOT Refined Analysis
  82. GRB 090904B: Swift/UVOT Refined Analysis
  83. GRB 090902B: Suzaku WAM observation of the prompt emission
  84. GRB 090904A: Swift-XRT refined analysis
  85. GRB 090902B: VLA radio detection
  86. GRB 090904B: Enhanced Swift-XRT position
  87. GRB 090904A: Enhanced Swift-XRT position
  88. GRB 090904A: NOT observations
  89. GRB 090902B: WSRT Radio Observation
  90. GRB090904B: REM observations
  91. GRB 090904B: Swift detection of a burst
  92. GRB 090904A: ROTSE-III Optical Limits
  93. GRB 090904: Swift detection of a burst
  94. GRB 090902B: Swift/UVOT refined analysis
  95. GRB 090902B: GROND NIR Afterglow Observations
  96. GRB 090902B: Enhanced Swift-XRT position
  97. GRB090902B: Swift/UVOT observations
  98. GRB 090902B: Swift/XRT Afterglow Candidate
  99. GRB 090902B: Fermi LAT detection
  100. GRB 090902B: Fermi GBM detection of a bright burst

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