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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 090417B: Swift detection of a burst
  2. GRB 090417: 2MASS galaxy within BAT Localization
  3. GRB 090417: Swift detection of a short burst
  4. GRB 090412: Fermi GBM detection
  5. GRB 090411B: Fermi GBM detection
  6. GRB 090411A: Fermi GBM detection
  7. GRB 090410: Suzaku WAM observation of the prompt emission
  8. GRB 090410: GROND upper limits
  9. Fermi GBM trigger 261106787 is not a GRB
  10. GRB 090410: MITSuME optical upper limits
  11. GRB 090408b: IPN Triangulation
  12. GRB 090328b: IPN Triangulation
  13. GRB 090410: Swift-BAT refined analysis
  14. GRB 090410: Swift detection of a burst
  15. Konus-Wind and Konus-RF observations of GRB 090408b
  16. GRB090408 : TAOS optical observations
  17. GRB 090409: Fermi GBM detection
  18. Swift-BAT Trigger 348781 is not a GRB
  19. Swift-BAT Trigger 348720 is not a GRB
  20. GRB 090406: pseudo-z= 0.91 from prompt emission spectrum
  21. GRB090408, RIMOTS optical upper limits
  22. GRB 090408: Xinglong TNT optical Upper Limit
  23. Swift-BAT trigger 348781: almost certainly not a burst
  24. Fermi GBM Detection of a weak source
  25. GRB 090408B: MASTER II-Kourovka optical observations
  26. GRB 090408: Swift detection of a burst
  27. GRB 090407: GROND upper limits
  28. GRB 090407: VLT observations
  29. GRB 090407: Swift-XRT refined analysis
  30. GRB 090407: Swift UVOT Upper Limits
  31. GRB 090407: Enhanced Swift-XRT position
  32. GRB 090407: Swift-BAT refined analysis
  33. Konus-Wind and Konus-RF observations of GRB 090406
  34. GRB 090407: ROTSE-III Optical Limits
  35. GRB 090407: Swift detection of a burst
  36. GRB 090404: millimeter detection
  37. GRB 090404: nIR observations at Calar Alto
  38. GRB 090405: Fermi GBM Detection
  39. GRB 090403: Fermi GBM detection
  40. GRB 090404: GROND upper limits
  41. GRB 090404: further NOT observations
  42. Swift/UVOT observations of GRB090404
  43. GRB 090404: NOT observations
  44. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  45. GRB 090404: Swift-XRT Team refined analysis
  46. GRB 090404: Xinglong TNT optical Upper Limit
  47. GRB 090404: Swift-BAT refined analysis
  48. GRB 090404: Enhanced Swift-XRT position
  49. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  50. GRB 090404: Swift detection of a burst
  51. GRB 090401A: Suzaku WAM observation of the prompt emission
  52. GRB 090401B: Suzaku WAM observation of the prompt emission
  53. Konus-Wind observation of GRB 090401B
  54. GRB 090401B: Xinglong TNT optical Upper Limit
  55. GRB 090401B: VLA radio upper limit
  56. GRB 090401B: Upper limits of MITSuME optical observation
  57. GRB090401B, RIMOTS optical upper limits
  58. GRB 090401B: NOT optical observations
  59. GRB 090328: Fermi-LAT refined analysis
  60. Swift/UVOT observations of GRB090401B
  61. GRB 090401B: AGILE refined analysis
  62. Swift/UVOT observations of GRB090401B
  63. GRB 090401B: Swift XRT Refined Analysis
  64. GRB 090331: Fermi GBM detection
  65. Konus-Wind observation of GRB 090401A
  66. GRB 090401B: Enhanced Swift-XRT position
  67. AGILE Gamma-ray detection of GRB 090401B
  68. GRB 090401B: Swift-BAT refined analysis
  69. Swift/UVOT detection of GRB090401B
  70. GRB 090401B: Swift detection of a burst
  71. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  72. GRB 090401, Swift-BAT refined analysis
  73. GRB 090323: Further TLS detections - a break?
  74. GRB 090401: Swift detection of a burst
  75. GRB 090324: Suzaku WAM observation of the prompt emission
  76. GRB 090328: Radio afterglow detection
  77. GRB 090326: Fermi GBM detection
  78. GRB 090328: BOOTES-3 optical observations
  79. GRB 090328: Fermi GBM Spectral Analysis
  80. GRB 090328B: Fermi GBM Detection
  81. GRB 090330: Fermi GBM detection
  82. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  83. GRB 090328: Gemini South Redshift
  84. GRB 090328: Swift XRT refined analysis
  85. GRB090323: Optical observations from NOT
  86. Konus-Wind observation of GRB 090328
  87. GRB 090328: IPN Triangulation
  88. GRB 090328: Swift UVOT observations
  89. GRB 090323: WSRT Radio Detection
  90. GRB 090328: Updated position/optical afterglow candidate
  91. GRB 090328: Possible Swift/XRT detection
  92. Fermi LAT and GBM detections of GRB090328
  93. GRB 090323: Radio afterglow detection
  94. GRB 090323: Additional Lick observations
  95. GRB 090323: TLS detection at 5 days, no break
  96. GRB 090327: Fermi GBM detection
  97. GRB 090323: Faulkes Telescope South Observations
  98. GRB 090320B: MASTER-Net prompt optical observations
  99. GRB 090323: RTT150 optical observations
  100. GRB 090323: Lick observations

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