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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 090528B: Fermi GBM detection
  2. GRB 090528: Fermi GBM detection
  3. GRB 090530: Enhanced Swift-XRT position
  4. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  5. GRB 090530: Swift-BAT refined analysis
  6. GRB 090530: GRAS002 refined OA analysis
  7. GRB 090530: GRAS002 optical observations
  8. GRB 090530: PAIRITEL NIR Detections
  9. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  10. GRB 090530: Swift detection of a burst with an optical counterpart
  11. GRB 090529: optical observations
  12. GRB 090529: TLS Afterglow Observations
  13. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  14. GRB 090529: Swift-BAT refined analysis
  15. GRB 090529: Enhanced Swift-XRT position
  16. GRB 090529: Preliminary Swift/UVOT Upper Limit
  17. GRB 090529: Xinglong TNT optical observation
  18. GRB 090529: Swift detection of a burst
  19. GRB 090520D: Fermi GBM detection
  20. GRB 090520C: Fermi GBM detection
  21. GRB 090520B: Fermi GBM detection
  22. GRB090518B optical limit by "Pi of the Sky"
  23. GRB 090522 : Fermi GBM detection
  24. GRB 090524: Fermi GBM detection
  25. GRB 090518 - NOT upper limit
  26. GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
  27. GRB 090513B: Fermi GBM detection
  28. GRB 090520: GROND upper limits
  29. GRB 090518: Fermi GBM detection
  30. GRB 090516C: Fermi GBM detection
  31. GRB 090520 Swift-BAT detection of a burst in ground analysis
  32. GRB 090423: Fermi GBM T90 follow-up analysis results
  33. GRB 090516: Fermi GBM observation
  34. GRB 090516B: Fermi GBM detection
  35. GRB 090519B: Fermi GBM detection
  36. GRB 090519: Swift-XRT refined analysis
  37. GRB 090519: NOT refined analysis
  38. GRB 090519: VLT spectroscopic redshift
  39. GRB 090519: GROND observation
  40. GRB 090519: Swift/UVOT Upper Limits
  41. GRB 090519, Swift-BAT refined analysis
  42. GRB 090519: Enhanced Swift-XRT position
  43. GRB 090519: Limits from BOOTES-1B
  44. GRB 090519: NOT afterglow candidate
  45. GRB 090519: FARO Chante Perdrix Observatory optical observations
  46. GRB 090519: TAROT Calern observatory optical observations
  47. GRB 090519: Swift detection of a burst
  48. GRB 090511: Fermi GBM Detection
  49. GRB 090514: Fermi GBM detection
  50. GRB 090518: Swift/UVOT Upper Limits
  51. GRB 090516: Observations from Stardome Observatory
  52. GRB090518: GROND upper limits
  53. GRB 090518: P60 Observations
  54. GRB 090518, Swift-BAT refined analysis
  55. GRB 090518B: Fermi GBM detection
  56. GRB 090516, RIMOTS optical upper limits
  57. GRB090513: Fermi GBM detection
  58. GRB090518 : Optical upper limit by MOA-II telescope
  59. GRB 090518: Swift-XRT refined analysis
  60. GRB 090518: Enhanced Swift-XRT position
  61. GRB 090518: Swift detection of a burst
  62. GRB 090515: Swift/BAT spectral lag results
  63. GRB 090516: Swift-BAT refined analysis
  64. GRB 090516: VLT spectrum (correction & update)
  65. GRB 090516: GROND OBSERVATIONS
  66. GRB 090516: VLT redshift
  67. GRB 090516 - Zadko Telescope observations
  68. GRB 090516: NOT optical observations
  69. GRB 090516: Swift XRT refined analysis
  70. GRB 090516: Swift/UVOT Observations
  71. GRB 090516: Enhanced Swift-XRT position
  72. GRB 090516: Faulkes Telescope South optical afterglow
  73. GRB 090516: Swift detection of a burst
  74. GRB 090515: VLA observations
  75. GRB 090515: Lick Upper Limits
  76. GRB 090515: ROVOR Upper Limit
  77. GRB 090515: MMT/MMIRS NIR Upper Limit
  78. GRB 090515: Swift/UVOT Observations
  79. GRB 090515: Swift-XRT refined analysis
  80. GRB 090515: Enhanced Swift-XRT position
  81. GRB 090509: Fermi GBM observation
  82. GRB 090515: Swift-BAT refined spectral analysis
  83. GRB 090515: Swift-BAT refined analysis
  84. GRB 090509 - Zadko Telescope observations
  85. GRB 090515: Gemini-N upper limit
  86. GRB 090515: WIYN NIR Upper Limit
  87. GRB 090515: Super-LOTIS Upper Limits
  88. GRB 090515: PAIRITEL Upper Limits
  89. GRB 090515: KAIT optical upper limits
  90. GRB 090515: ROTSE-III Optical Limits
  91. GRB 090515: Swift detection of a short burst
  92. GRB 090510: Suzaku WAM observation of the prompt emission
  93. GRB 090510, Radio limits
  94. GRB090510: VLT/FORS2 spectroscopic redshift
  95. GRB 090510: GROND observations
  96. GRB 090510: Swift/UVOT host galaxy candidates
  97. GRB 090510: Fermi-LAT follow-up analysis
  98. GRB 090509, further Swift-BAT refined analysis
  99. Fermi Gamma-ray Burst Monitor trigger 263649437 is not a GRB
  100. GRB 090510B: Fermi GBM detection

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