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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"

27234 results found.

  1. GRB 090418B: Faulkes Telescope North observations
  2. GRB 090418A: Swift/UVOT Observations
  3. GRB 090417B: Swift/UVOT Upper Limits
  4. GRB 090417B Correction to the BAT refined analysis position
  5. GRB 090419: Swift-XRT refined analysis
  6. Konus-Wind observation of GRB 090418B
  7. GRB 090419: GROND detection of afterglow candidate
  8. GRB 090419: Swift-BAT refined analysis
  9. VLA radio detection of GRB 090418
  10. VLA radio upper limit on GRB 090417B
  11. GRB 090419: Enhanced Swift-XRT position
  12. GRB 090418: Swift XRT refined analysis
  13. GRB 090418A: ROTSE-III Refined Analysis
  14. GRB 090419: Swift detection of a burst
  15. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  16. GRB 090418: Swift-BAT refined analysis
  17. GRB 090417B: Swift-XRT refined analysis
  18. GRB 090418: Enhanced Swift-XRT position
  19. GRB 090417B: Swift-BAT further refined analysis
  20. GRB 090418: PAIRITEL NIR detection
  21. GRB 090418: ROTSE-III Confirmation of Optical Counterpart
  22. GRB 090418: Swift detection of a burst with optical afterglow
  23. GRB 090417B: Liverpool Telescope observations
  24. GRB 090417B: Swift-BAT refined analysis
  25. GRB 090417A: Swift-BAT refined analysis
  26. GRB 090417B: Swift detection of a burst
  27. GRB 090417: 2MASS galaxy within BAT Localization
  28. GRB 090417: Swift detection of a short burst
  29. GRB 090412: Fermi GBM detection
  30. GRB 090411B: Fermi GBM detection
  31. GRB 090411A: Fermi GBM detection
  32. GRB 090410: Suzaku WAM observation of the prompt emission
  33. GRB 090410: Swift-BAT refined analysis
  34. GRB 090410: Swift detection of a burst
  35. GRB 090409: Fermi GBM detection
  36. Swift-BAT Trigger 348781 is not a GRB
  37. Swift-BAT Trigger 348720 is not a GRB
  38. GRB090408, RIMOTS optical upper limits
  39. Swift-BAT trigger 348781: almost certainly not a burst
  40. Fermi GBM Detection of a weak source
  41. GRB 090408B: MASTER II-Kourovka optical observations
  42. GRB 090408: Swift detection of a burst
  43. GRB 090407: Swift-XRT refined analysis
  44. GRB 090407: Swift UVOT Upper Limits
  45. GRB 090407: Enhanced Swift-XRT position
  46. GRB 090407: Swift-BAT refined analysis
  47. GRB 090407: ROTSE-III Optical Limits
  48. GRB 090407: Swift detection of a burst
  49. GRB 090404: millimeter detection
  50. GRB 090404: nIR observations at Calar Alto
  51. GRB 090405: Fermi GBM Detection
  52. GRB 090403: Fermi GBM detection
  53. Swift/UVOT observations of GRB090404
  54. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  55. GRB 090404: Swift-XRT Team refined analysis
  56. GRB 090404: Swift-BAT refined analysis
  57. GRB 090404: Enhanced Swift-XRT position
  58. GRB 090404: Swift detection of a burst
  59. GRB 090401A: Suzaku WAM observation of the prompt emission
  60. GRB 090401B: Suzaku WAM observation of the prompt emission
  61. Konus-Wind observation of GRB 090401B
  62. GRB 090401B: VLA radio upper limit
  63. GRB090401B, RIMOTS optical upper limits
  64. Swift/UVOT observations of GRB090401B
  65. GRB 090401B: AGILE refined analysis
  66. Swift/UVOT observations of GRB090401B
  67. GRB 090401B: Swift XRT Refined Analysis
  68. GRB 090331: Fermi GBM detection
  69. Konus-Wind observation of GRB 090401A
  70. GRB 090401B: Enhanced Swift-XRT position
  71. AGILE Gamma-ray detection of GRB 090401B
  72. GRB 090401B: Swift-BAT refined analysis
  73. Swift/UVOT detection of GRB090401B
  74. GRB 090401B: Swift detection of a burst
  75. GRB 090401, Swift-BAT refined analysis
  76. GRB 090323: Further TLS detections - a break?
  77. GRB 090401: Swift detection of a burst
  78. GRB 090328: Radio afterglow detection
  79. GRB 090326: Fermi GBM detection
  80. GRB 090328: BOOTES-3 optical observations
  81. GRB 090328B: Fermi GBM Detection
  82. GRB 090330: Fermi GBM detection
  83. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  84. GRB 090328: Swift XRT refined analysis
  85. GRB 090328: Swift UVOT observations
  86. GRB 090323: WSRT Radio Detection
  87. GRB 090328: Updated position/optical afterglow candidate
  88. GRB 090328: Possible Swift/XRT detection
  89. Fermi LAT and GBM detections of GRB090328
  90. GRB 090323: Radio afterglow detection
  91. GRB 090323: TLS detection at 5 days, no break
  92. GRB 090327: Fermi GBM detection
  93. GRB 090323 TLS detection - still bright
  94. GRB 090323: UVOT Detection of Afterglow
  95. GRB 090323: Swift-XRT refined analysis
  96. GRB 090323: GROND Detection of the Afterglow and Photo-z
  97. GRB 090323: Possible XRT Counterpart
  98. GRB 090320C: Fermi GBM Detection
  99. GRB 090320B: Fermi GBM detection.
  100. GRB 090319: Fermi GBM detection

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