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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"

20350 results found.

  1. GRB 091010: Enhanced XRT position
  2. GRB 091010 optical upper limits
  3. GRB 091010: GROND afterglow candidate
  4. GRB 091010: Swift/UVOT Upper Limits
  5. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  6. GRB 090518: Skynet/PROMPT Observations
  7. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  8. GRB 090904A: afterglow confirmation
  9. GRB 090812: Skynet/PROMPT and GORT Observations
  10. GRB 090926B: Skynet/PROMPT Observations
  11. GRB 091003: WHT ACAM observations
  12. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  13. GRB 091003: UVOT-enhanced XRT position
  14. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  15. GRB 091003A: Fermi LAT detection
  16. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  17. GRB 090929A, Swift-BAT refined analysis
  18. GRB 090929B, Swift-BAT refined analysis
  19. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  20. GRB 090926A: Fermi LAT and GBM refined analysis
  21. GRB 090929B: Gemini-N upper limits
  22. GRB 090929B: Swift/UVOT Observations
  23. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  24. GRB 090929A BAT location of the Fermi GBM burst
  25. Correction: GRB 090929B: Enhanced Swift-XRT position
  26. GRB 090929: Enhanced Swift-XRT position
  27. GRB 090929B: Swift detection of a burst
  28. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  29. Konus-Wind and Konus-RF observations of GRB 090926A
  30. GRB 090927: Zadko Telescope observations
  31. Swift/UVOT observations of GRB 090927
  32. GRB 090927: Swift XRT refined analysis
  33. GRB 090927: Enhanced Swift-XRT position
  34. GRB090926B: Swift/UVOT Upper Limits
  35. GRB090926A: Swift/UVOT observations
  36. GRB 090926B: optical object in error circle
  37. GRB 090926B: NOT optical observation
  38. GRB 090926B: Swift XRT refined analysis
  39. GRB 090926A: Swift/UVOT detection of an optical afterglow
  40. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  41. GRB090926A: UVOT-enhanced XRT position
  42. GRB 090926B: Swift detection of a burst
  43. GRB 090926: Fermi LAT detection
  44. GRB 090926: Fermi GBM detection
  45. GRB090904B : IRSF NIR upper limit
  46. GRB 090715B: Skynet/PROMPT Detections
  47. GRB 090916: Swift-XRT upper limit
  48. GRB 090915: GROND upper limits
  49. Short-Duration GRB 090916: Skynet/PROMPT Observations
  50. GRB 090915: SARA detection of afterglow candidate
  51. GRB 090912: optical observation
  52. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  53. GRB 090902B: Skynet/PROMPT Observations
  54. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  55. GRB 090915 Swift-BAT detection of a burst in ground analysis
  56. GRB 090827: Confirmation of the X-ray afterglow
  57. GRB 090912, Swift-BAT refined analysis
  58. GRB 090912: Swift/UVOT Upper Limits
  59. GRB 090912 optical upper limit
  60. GRB 090912: Enhanced Swift-XRT position
  61. GRB 090912: Swift detection of a burst
  62. GRB 090814A: Skynet/DSO & GORT Observations
  63. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  64. GRB 090904B: GROND detection of the optical afterglow
  65. GRB 090831A: Suzaku WAM observation of the prompt emission
  66. GRB 090904B: Swift/UVOT Refined Analysis
  67. GRB 090902B: Suzaku WAM observation of the prompt emission
  68. GRB 090904B: MOA-II Optical observation
  69. GRB 090902B: VLA radio detection
  70. GRB 090904B: Enhanced Swift-XRT position
  71. GRB 090904A: Enhanced Swift-XRT position
  72. GRB 090904A: NOT observations
  73. GRB 090902B: WSRT Radio Observation
  74. GRB090904B: REM observations
  75. GRB 090904B: Swift detection of a burst
  76. GRB 090904: Swift detection of a burst
  77. GRB 090902B: Swift/UVOT refined analysis
  78. GRB 090902B: GROND NIR Afterglow Observations
  79. GRB 090902B: Fermi LAT and GBM refined analysis.
  80. GRB 090902B: Enhanced Swift-XRT position
  81. GRB090902B: Swift/UVOT observations
  82. GRB 090902B: Swift/XRT Afterglow Candidate
  83. GRB 090902B: Fermi LAT detection
  84. GRB 090831C: GROND upper limits
  85. Swift Trigger 361477, called GRB090831B, is probably not real.
  86. GRB090831C: Swift/UVOT upper limits
  87. GRB 090831B: MITSuME optical upper limits
  88. GRB 090831C: Enhanced Swift-XRT position
  89. GRB 090831C: Swift detection of a burst
  90. GRB 090831B, RIMOTS optical upper limits
  91. GRB 090831B: Swift detection of a possible burst
  92. GRB090829: Fermi GBM Detection
  93. GRB 090827: Swift XRT and UVOT observations
  94. GRB 090827 Burst discovered in BAT ground analysis
  95. GRB 090817 - TLS Observations
  96. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  97. GRB 090823 Correction to BAT position
  98. GRB 090817: No host galaxy, no supernova
  99. GRB 090823 Long burst with IPN triangulation and BAT position
  100. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate

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