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

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