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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 090513B: Fermi GBM detection
  2. GRB 090520: GROND upper limits
  3. GRB 090518: Fermi GBM detection
  4. GRB 090516C: Fermi GBM detection
  5. GRB 090520 Swift-BAT detection of a burst in ground analysis
  6. GRB 090423: Fermi GBM T90 follow-up analysis results
  7. GRB 090516: Fermi GBM observation
  8. GRB 090516B: Fermi GBM detection
  9. GRB 090519B: Fermi GBM detection
  10. GRB 090519: Swift-XRT refined analysis
  11. GRB 090519: NOT refined analysis
  12. GRB 090519: VLT spectroscopic redshift
  13. GRB 090519: GROND observation
  14. GRB 090519: Swift/UVOT Upper Limits
  15. GRB 090519, Swift-BAT refined analysis
  16. GRB 090519: Enhanced Swift-XRT position
  17. GRB 090519: Limits from BOOTES-1B
  18. GRB 090519: NOT afterglow candidate
  19. GRB 090519: FARO Chante Perdrix Observatory optical observations
  20. GRB 090519: TAROT Calern observatory optical observations
  21. GRB 090519: Swift detection of a burst
  22. GRB 090511: Fermi GBM Detection
  23. GRB 090514: Fermi GBM detection
  24. GRB 090518: Swift/UVOT Upper Limits
  25. GRB 090516: Observations from Stardome Observatory
  26. GRB090518: GROND upper limits
  27. GRB 090518: P60 Observations
  28. GRB 090518, Swift-BAT refined analysis
  29. GRB 090518B: Fermi GBM detection
  30. GRB 090516, RIMOTS optical upper limits
  31. GRB090513: Fermi GBM detection
  32. GRB090518 : Optical upper limit by MOA-II telescope
  33. GRB 090518: Swift-XRT refined analysis
  34. GRB 090518: Enhanced Swift-XRT position
  35. GRB 090518: Swift detection of a burst
  36. GRB 090515: Swift/BAT spectral lag results
  37. GRB 090516: Swift-BAT refined analysis
  38. GRB 090516: VLT spectrum (correction & update)
  39. GRB 090516: GROND OBSERVATIONS
  40. GRB 090516: VLT redshift
  41. GRB 090516 - Zadko Telescope observations
  42. GRB 090516: NOT optical observations
  43. GRB 090516: Swift XRT refined analysis
  44. GRB 090516: Swift/UVOT Observations
  45. GRB 090516: Enhanced Swift-XRT position
  46. GRB 090516: Faulkes Telescope South optical afterglow
  47. GRB 090516: Swift detection of a burst
  48. GRB 090515: VLA observations
  49. GRB 090515: Lick Upper Limits
  50. GRB 090515: ROVOR Upper Limit
  51. GRB 090515: MMT/MMIRS NIR Upper Limit
  52. GRB 090515: Swift/UVOT Observations
  53. GRB 090515: Swift-XRT refined analysis
  54. GRB 090515: Enhanced Swift-XRT position
  55. GRB 090509: Fermi GBM observation
  56. GRB 090515: Swift-BAT refined spectral analysis
  57. GRB 090515: Swift-BAT refined analysis
  58. GRB 090509 - Zadko Telescope observations
  59. GRB 090515: Gemini-N upper limit
  60. GRB 090515: WIYN NIR Upper Limit
  61. GRB 090515: Super-LOTIS Upper Limits
  62. GRB 090515: PAIRITEL Upper Limits
  63. GRB 090515: KAIT optical upper limits
  64. GRB 090515: ROTSE-III Optical Limits
  65. GRB 090515: Swift detection of a short burst
  66. GRB 090510: Suzaku WAM observation of the prompt emission
  67. GRB 090510, Radio limits
  68. GRB090510: VLT/FORS2 spectroscopic redshift
  69. GRB 090510: GROND observations
  70. GRB 090510: Swift/UVOT host galaxy candidates
  71. GRB 090510: Fermi-LAT follow-up analysis
  72. GRB 090509, further Swift-BAT refined analysis
  73. Fermi Gamma-ray Burst Monitor trigger 263649437 is not a GRB
  74. GRB 090510B: Fermi GBM detection
  75. GRB 090502: Fermi GBM detection
  76. GRB 090510: correction to GCN 9344
  77. Konus-Wind observation of GRB 090510
  78. AGILE detection of GRB 090510
  79. GRB 090510: UVOT refined analysis
  80. GRB 090510: Swift XRT refined analysis
  81. GRB 090510: correction to coordinates in GCN 9338
  82. GRB 090510: Enhanced Swift-XRT position
  83. GRB 090510: NOT afterglow confirmation
  84. GRB 090510: Swift-BAT refined analysis
  85. GRB 090510: Fermi GBM detection
  86. GRB 090509: Swift-BAT refined analysis
  87. Fermi LAT detection of GRB 090510
  88. GRB 090509, SMARTS optical/IR afterglow observations
  89. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  90. GRB 090510: Swift detection of a short hard burst
  91. GRB 090408: optical upper limit
  92. GRB 090418A: optical observation
  93. GRB 090509: GROND further analysis and redshift limit
  94. GRB 090509: REM NIR afterglow
  95. GRB 090509: GROND afterglow candidate
  96. GRB 090509: Swift detection of a burst
  97. GRB 090323: optical observations
  98. GRB 090423: optical limit
  99. GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
  100. GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m

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