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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"

20363 results found.

  1. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  2. GRB 091020: Swift detection of a burst with an optical afterglow
  3. GRB 091018 : Faulkes Telescope South Observations
  4. GRB 091018: VLT/X-shooter spectra
  5. GRB091018: Swift/UVOT observations
  6. GRB 091018: GROND observations
  7. GRB 091018: Enhanced Swift-XRT position
  8. GRB 091018: Swift detection of a burst with optical afterglow
  9. GRB 091010: optical obsevation
  10. Radio observation of GRB090927 with ATCA
  11. Radio observation of GRB090926a with ATCA
  12. Radio observation of GRB080916c with ATCA
  13. GRB 090531A: Skynet/PROMPT Observations
  14. GRB 091010: Enhanced XRT position
  15. GRB 091010 optical upper limits
  16. GRB 091010: GROND afterglow candidate
  17. GRB 091010: Swift/UVOT Upper Limits
  18. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  19. GRB 090518: Skynet/PROMPT Observations
  20. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  21. GRB 090904A: afterglow confirmation
  22. GRB 090812: Skynet/PROMPT and GORT Observations
  23. GRB 090926B: Skynet/PROMPT Observations
  24. GRB 091003: WHT ACAM observations
  25. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  26. GRB 091003: UVOT-enhanced XRT position
  27. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  28. GRB 091003A: Fermi LAT detection
  29. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  30. GRB 090929A, Swift-BAT refined analysis
  31. GRB 090929B, Swift-BAT refined analysis
  32. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  33. GRB 090926A: Fermi LAT and GBM refined analysis
  34. GRB 090929B: Gemini-N upper limits
  35. GRB 090929B: Swift/UVOT Observations
  36. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  37. GRB 090929A BAT location of the Fermi GBM burst
  38. Correction: GRB 090929B: Enhanced Swift-XRT position
  39. GRB 090929: Enhanced Swift-XRT position
  40. GRB 090929B: Swift detection of a burst
  41. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  42. Konus-Wind and Konus-RF observations of GRB 090926A
  43. GRB 090927: Zadko Telescope observations
  44. Swift/UVOT observations of GRB 090927
  45. GRB 090927: Swift XRT refined analysis
  46. GRB 090927: Enhanced Swift-XRT position
  47. GRB090926B: Swift/UVOT Upper Limits
  48. GRB090926A: Swift/UVOT observations
  49. GRB 090926B: optical object in error circle
  50. GRB 090926B: NOT optical observation
  51. GRB 090926B: Swift XRT refined analysis
  52. GRB 090926A: Swift/UVOT detection of an optical afterglow
  53. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  54. GRB090926A: UVOT-enhanced XRT position
  55. GRB 090926B: Swift detection of a burst
  56. GRB 090926: Fermi LAT detection
  57. GRB 090926: Fermi GBM detection
  58. GRB090904B : IRSF NIR upper limit
  59. GRB 090715B: Skynet/PROMPT Detections
  60. GRB 090916: Swift-XRT upper limit
  61. GRB 090915: GROND upper limits
  62. Short-Duration GRB 090916: Skynet/PROMPT Observations
  63. GRB 090915: SARA detection of afterglow candidate
  64. GRB 090912: optical observation
  65. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  66. GRB 090902B: Skynet/PROMPT Observations
  67. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  68. GRB 090915 Swift-BAT detection of a burst in ground analysis
  69. GRB 090827: Confirmation of the X-ray afterglow
  70. GRB 090912, Swift-BAT refined analysis
  71. GRB 090912: Swift/UVOT Upper Limits
  72. GRB 090912 optical upper limit
  73. GRB 090912: Enhanced Swift-XRT position
  74. GRB 090912: Swift detection of a burst
  75. GRB 090814A: Skynet/DSO & GORT Observations
  76. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  77. GRB 090904B: GROND detection of the optical afterglow
  78. GRB 090831A: Suzaku WAM observation of the prompt emission
  79. GRB 090904B: Swift/UVOT Refined Analysis
  80. GRB 090902B: Suzaku WAM observation of the prompt emission
  81. GRB 090904B: MOA-II Optical observation
  82. GRB 090902B: VLA radio detection
  83. GRB 090904B: Enhanced Swift-XRT position
  84. GRB 090904A: Enhanced Swift-XRT position
  85. GRB 090904A: NOT observations
  86. GRB 090902B: WSRT Radio Observation
  87. GRB090904B: REM observations
  88. GRB 090904B: Swift detection of a burst
  89. GRB 090904: Swift detection of a burst
  90. GRB 090902B: Swift/UVOT refined analysis
  91. GRB 090902B: GROND NIR Afterglow Observations
  92. GRB 090902B: Fermi LAT and GBM refined analysis.
  93. GRB 090902B: Enhanced Swift-XRT position
  94. GRB090902B: Swift/UVOT observations
  95. GRB 090902B: Swift/XRT Afterglow Candidate
  96. GRB 090902B: Fermi LAT detection
  97. GRB 090831C: GROND upper limits
  98. Swift Trigger 361477, called GRB090831B, is probably not real.
  99. GRB090831C: Swift/UVOT upper limits
  100. GRB 090831B: MITSuME optical upper limits

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