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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: Galaxy redshift
  2. GRB 090417B: Swift-XRT refined analysis
  3. GRB 090418: Enhanced Swift-XRT position
  4. GRB 090417B: Swift-BAT further refined analysis
  5. GRB 090418: PAIRITEL NIR detection
  6. GRB 090418 Lick Redshift
  7. GRB 090418: ROTSE-III Confirmation of Optical Counterpart
  8. GRB 090418: Swift detection of a burst with optical afterglow
  9. GRB 090418 OA candidate
  10. GRB 090411B: Suzaku WAM observation of the prompt emission
  11. GRB 090411A: Suzaku WAM observation of the prompt emission
  12. GRB 090417B: Subaru NIR Observations
  13. GRB 090417B: Liverpool Telescope observations
  14. GRB 090417B: MITSuME Okayama optical upper limits
  15. GRB090417B: Xinglong TNT optical upper limit
  16. GRB 090417B: optical observations
  17. GRB090417B: optical observations
  18. GRB 090417B: Swift-BAT refined analysis
  19. GRB 090417A: Swift-BAT refined analysis
  20. GRB 090417A: Early-type nature of the putative host
  21. GRB 090417A: nearby galaxy redshift
  22. GRB 090417B: Swift detection of a burst
  23. GRB 090417: 2MASS galaxy within BAT Localization
  24. GRB 090417: Swift detection of a short burst
  25. GRB 090412: Fermi GBM detection
  26. GRB 090411B: Fermi GBM detection
  27. GRB 090411A: Fermi GBM detection
  28. GRB 090410: Suzaku WAM observation of the prompt emission
  29. GRB 090410: GROND upper limits
  30. Fermi GBM trigger 261106787 is not a GRB
  31. GRB 090410: MITSuME optical upper limits
  32. GRB 090408b: IPN Triangulation
  33. GRB 090328b: IPN Triangulation
  34. GRB 090410: Swift-BAT refined analysis
  35. GRB 090410: Swift detection of a burst
  36. Konus-Wind and Konus-RF observations of GRB 090408b
  37. GRB090408 : TAOS optical observations
  38. GRB 090409: Fermi GBM detection
  39. Swift-BAT Trigger 348781 is not a GRB
  40. Swift-BAT Trigger 348720 is not a GRB
  41. GRB 090406: pseudo-z= 0.91 from prompt emission spectrum
  42. GRB090408, RIMOTS optical upper limits
  43. GRB 090408: Xinglong TNT optical Upper Limit
  44. Swift-BAT trigger 348781: almost certainly not a burst
  45. Fermi GBM Detection of a weak source
  46. GRB 090408B: MASTER II-Kourovka optical observations
  47. GRB 090408: Swift detection of a burst
  48. GRB 090407: GROND upper limits
  49. GRB 090407: VLT observations
  50. GRB 090407: Swift-XRT refined analysis
  51. GRB 090407: Swift UVOT Upper Limits
  52. GRB 090407: Enhanced Swift-XRT position
  53. GRB 090407: Swift-BAT refined analysis
  54. Konus-Wind and Konus-RF observations of GRB 090406
  55. GRB 090407: ROTSE-III Optical Limits
  56. GRB 090407: Swift detection of a burst
  57. GRB 090404: millimeter detection
  58. GRB 090404: nIR observations at Calar Alto
  59. GRB 090405: Fermi GBM Detection
  60. GRB 090403: Fermi GBM detection
  61. GRB 090404: GROND upper limits
  62. GRB 090404: further NOT observations
  63. Swift/UVOT observations of GRB090404
  64. GRB 090404: NOT observations
  65. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  66. GRB 090404: Swift-XRT Team refined analysis
  67. GRB 090404: Xinglong TNT optical Upper Limit
  68. GRB 090404: Swift-BAT refined analysis
  69. GRB 090404: Enhanced Swift-XRT position
  70. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  71. GRB 090404: Swift detection of a burst
  72. GRB 090401A: Suzaku WAM observation of the prompt emission
  73. GRB 090401B: Suzaku WAM observation of the prompt emission
  74. Konus-Wind observation of GRB 090401B
  75. GRB 090401B: Xinglong TNT optical Upper Limit
  76. GRB 090401B: VLA radio upper limit
  77. GRB 090401B: Upper limits of MITSuME optical observation
  78. GRB090401B, RIMOTS optical upper limits
  79. GRB 090401B: NOT optical observations
  80. GRB 090328: Fermi-LAT refined analysis
  81. Swift/UVOT observations of GRB090401B
  82. GRB 090401B: AGILE refined analysis
  83. Swift/UVOT observations of GRB090401B
  84. GRB 090401B: Swift XRT Refined Analysis
  85. GRB 090331: Fermi GBM detection
  86. Konus-Wind observation of GRB 090401A
  87. GRB 090401B: Enhanced Swift-XRT position
  88. AGILE Gamma-ray detection of GRB 090401B
  89. GRB 090401B: Swift-BAT refined analysis
  90. Swift/UVOT detection of GRB090401B
  91. GRB 090401B: Swift detection of a burst
  92. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  93. GRB 090401, Swift-BAT refined analysis
  94. GRB 090323: Further TLS detections - a break?
  95. GRB 090401: Swift detection of a burst
  96. GRB 090324: Suzaku WAM observation of the prompt emission
  97. GRB 090328: Radio afterglow detection
  98. GRB 090326: Fermi GBM detection
  99. GRB 090328: BOOTES-3 optical observations
  100. GRB 090328: Fermi GBM Spectral Analysis

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