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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 090530A: ROTSE-III Detection of Optical Counterpart
  2. GRB 090530: Swift detection of a burst with an optical counterpart
  3. GRB 090529: optical observations
  4. GRB 090529: TLS Afterglow Observations
  5. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  6. GRB 090529: Swift-BAT refined analysis
  7. GRB 090529: Enhanced Swift-XRT position
  8. GRB 090529: Preliminary Swift/UVOT Upper Limit
  9. GRB 090529: Xinglong TNT optical observation
  10. GRB 090529: Swift detection of a burst
  11. GRB 090520D: Fermi GBM detection
  12. GRB 090520C: Fermi GBM detection
  13. GRB 090520B: Fermi GBM detection
  14. GRB090518B optical limit by "Pi of the Sky"
  15. GRB 090522 : Fermi GBM detection
  16. GRB 090524: Fermi GBM detection
  17. GRB 090518 - NOT upper limit
  18. GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
  19. GRB 090513B: Fermi GBM detection
  20. GRB 090520: GROND upper limits
  21. GRB 090518: Fermi GBM detection
  22. GRB 090516C: Fermi GBM detection
  23. GRB 090520 Swift-BAT detection of a burst in ground analysis
  24. GRB 090423: Fermi GBM T90 follow-up analysis results
  25. GRB 090516: Fermi GBM observation
  26. GRB 090516B: Fermi GBM detection
  27. GRB 090519B: Fermi GBM detection
  28. GRB 090519: Swift-XRT refined analysis
  29. GRB 090519: NOT refined analysis
  30. GRB 090519: VLT spectroscopic redshift
  31. GRB 090519: GROND observation
  32. GRB 090519: Swift/UVOT Upper Limits
  33. GRB 090519, Swift-BAT refined analysis
  34. GRB 090519: Enhanced Swift-XRT position
  35. GRB 090519: Limits from BOOTES-1B
  36. GRB 090519: NOT afterglow candidate
  37. GRB 090519: FARO Chante Perdrix Observatory optical observations
  38. GRB 090519: TAROT Calern observatory optical observations
  39. GRB 090519: Swift detection of a burst
  40. GRB 090511: Fermi GBM Detection
  41. GRB 090514: Fermi GBM detection
  42. GRB 090518: Swift/UVOT Upper Limits
  43. GRB 090516: Observations from Stardome Observatory
  44. GRB090518: GROND upper limits
  45. GRB 090518: P60 Observations
  46. GRB 090518, Swift-BAT refined analysis
  47. GRB 090518B: Fermi GBM detection
  48. GRB 090516, RIMOTS optical upper limits
  49. GRB090513: Fermi GBM detection
  50. GRB090518 : Optical upper limit by MOA-II telescope
  51. GRB 090518: Swift-XRT refined analysis
  52. GRB 090518: Enhanced Swift-XRT position
  53. GRB 090518: Swift detection of a burst
  54. GRB 090515: Swift/BAT spectral lag results
  55. GRB 090516: Swift-BAT refined analysis
  56. GRB 090516: VLT spectrum (correction & update)
  57. GRB 090516: GROND OBSERVATIONS
  58. GRB 090516: VLT redshift
  59. GRB 090516 - Zadko Telescope observations
  60. GRB 090516: NOT optical observations
  61. GRB 090516: Swift XRT refined analysis
  62. GRB 090516: Swift/UVOT Observations
  63. GRB 090516: Enhanced Swift-XRT position
  64. GRB 090516: Faulkes Telescope South optical afterglow
  65. GRB 090516: Swift detection of a burst
  66. GRB 090515: VLA observations
  67. GRB 090515: Lick Upper Limits
  68. GRB 090515: ROVOR Upper Limit
  69. GRB 090515: MMT/MMIRS NIR Upper Limit
  70. GRB 090515: Swift/UVOT Observations
  71. GRB 090515: Swift-XRT refined analysis
  72. GRB 090515: Enhanced Swift-XRT position
  73. GRB 090509: Fermi GBM observation
  74. GRB 090515: Swift-BAT refined spectral analysis
  75. GRB 090515: Swift-BAT refined analysis
  76. GRB 090509 - Zadko Telescope observations
  77. GRB 090515: Gemini-N upper limit
  78. GRB 090515: WIYN NIR Upper Limit
  79. GRB 090515: Super-LOTIS Upper Limits
  80. GRB 090515: PAIRITEL Upper Limits
  81. GRB 090515: KAIT optical upper limits
  82. GRB 090515: ROTSE-III Optical Limits
  83. GRB 090515: Swift detection of a short burst
  84. GRB 090510: Suzaku WAM observation of the prompt emission
  85. GRB 090510, Radio limits
  86. GRB090510: VLT/FORS2 spectroscopic redshift
  87. GRB 090510: GROND observations
  88. GRB 090510: Swift/UVOT host galaxy candidates
  89. GRB 090510: Fermi-LAT follow-up analysis
  90. GRB 090509, further Swift-BAT refined analysis
  91. Fermi Gamma-ray Burst Monitor trigger 263649437 is not a GRB
  92. GRB 090510B: Fermi GBM detection
  93. GRB 090502: Fermi GBM detection
  94. GRB 090510: correction to GCN 9344
  95. Konus-Wind observation of GRB 090510
  96. AGILE detection of GRB 090510
  97. GRB 090510: UVOT refined analysis
  98. GRB 090510: Swift XRT refined analysis
  99. GRB 090510: correction to coordinates in GCN 9338
  100. GRB 090510: Enhanced Swift-XRT position

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