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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: optical observations
  2. GRB090417B: optical observations
  3. GRB 090417B: Swift-BAT refined analysis
  4. GRB 090417A: Swift-BAT refined analysis
  5. GRB 090417A: Early-type nature of the putative host
  6. GRB 090417A: nearby galaxy redshift
  7. GRB 090417B: Swift detection of a burst
  8. GRB 090417: 2MASS galaxy within BAT Localization
  9. GRB 090417: Swift detection of a short burst
  10. GRB 090412: Fermi GBM detection
  11. GRB 090411B: Fermi GBM detection
  12. GRB 090411A: Fermi GBM detection
  13. GRB 090410: Suzaku WAM observation of the prompt emission
  14. GRB 090410: GROND upper limits
  15. Fermi GBM trigger 261106787 is not a GRB
  16. GRB 090410: MITSuME optical upper limits
  17. GRB 090408b: IPN Triangulation
  18. GRB 090328b: IPN Triangulation
  19. GRB 090410: Swift-BAT refined analysis
  20. GRB 090410: Swift detection of a burst
  21. Konus-Wind and Konus-RF observations of GRB 090408b
  22. GRB090408 : TAOS optical observations
  23. GRB 090409: Fermi GBM detection
  24. Swift-BAT Trigger 348781 is not a GRB
  25. Swift-BAT Trigger 348720 is not a GRB
  26. GRB 090406: pseudo-z= 0.91 from prompt emission spectrum
  27. GRB090408, RIMOTS optical upper limits
  28. GRB 090408: Xinglong TNT optical Upper Limit
  29. Swift-BAT trigger 348781: almost certainly not a burst
  30. Fermi GBM Detection of a weak source
  31. GRB 090408B: MASTER II-Kourovka optical observations
  32. GRB 090408: Swift detection of a burst
  33. GRB 090407: GROND upper limits
  34. GRB 090407: VLT observations
  35. GRB 090407: Swift-XRT refined analysis
  36. GRB 090407: Swift UVOT Upper Limits
  37. GRB 090407: Enhanced Swift-XRT position
  38. GRB 090407: Swift-BAT refined analysis
  39. Konus-Wind and Konus-RF observations of GRB 090406
  40. GRB 090407: ROTSE-III Optical Limits
  41. GRB 090407: Swift detection of a burst
  42. GRB 090404: millimeter detection
  43. GRB 090404: nIR observations at Calar Alto
  44. GRB 090405: Fermi GBM Detection
  45. GRB 090403: Fermi GBM detection
  46. GRB 090404: GROND upper limits
  47. GRB 090404: further NOT observations
  48. Swift/UVOT observations of GRB090404
  49. GRB 090404: NOT observations
  50. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  51. GRB 090404: Swift-XRT Team refined analysis
  52. GRB 090404: Xinglong TNT optical Upper Limit
  53. GRB 090404: Swift-BAT refined analysis
  54. GRB 090404: Enhanced Swift-XRT position
  55. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  56. GRB 090404: Swift detection of a burst
  57. GRB 090401A: Suzaku WAM observation of the prompt emission
  58. GRB 090401B: Suzaku WAM observation of the prompt emission
  59. Konus-Wind observation of GRB 090401B
  60. GRB 090401B: Xinglong TNT optical Upper Limit
  61. GRB 090401B: VLA radio upper limit
  62. GRB 090401B: Upper limits of MITSuME optical observation
  63. GRB090401B, RIMOTS optical upper limits
  64. GRB 090401B: NOT optical observations
  65. GRB 090328: Fermi-LAT refined analysis
  66. Swift/UVOT observations of GRB090401B
  67. GRB 090401B: AGILE refined analysis
  68. Swift/UVOT observations of GRB090401B
  69. GRB 090401B: Swift XRT Refined Analysis
  70. GRB 090331: Fermi GBM detection
  71. Konus-Wind observation of GRB 090401A
  72. GRB 090401B: Enhanced Swift-XRT position
  73. AGILE Gamma-ray detection of GRB 090401B
  74. GRB 090401B: Swift-BAT refined analysis
  75. Swift/UVOT detection of GRB090401B
  76. GRB 090401B: Swift detection of a burst
  77. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  78. GRB 090401, Swift-BAT refined analysis
  79. GRB 090323: Further TLS detections - a break?
  80. GRB 090401: Swift detection of a burst
  81. GRB 090324: Suzaku WAM observation of the prompt emission
  82. GRB 090328: Radio afterglow detection
  83. GRB 090326: Fermi GBM detection
  84. GRB 090328: BOOTES-3 optical observations
  85. GRB 090328: Fermi GBM Spectral Analysis
  86. GRB 090328B: Fermi GBM Detection
  87. GRB 090330: Fermi GBM detection
  88. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  89. GRB 090328: Gemini South Redshift
  90. GRB 090328: Swift XRT refined analysis
  91. GRB090323: Optical observations from NOT
  92. Konus-Wind observation of GRB 090328
  93. GRB 090328: IPN Triangulation
  94. GRB 090328: Swift UVOT observations
  95. GRB 090323: WSRT Radio Detection
  96. GRB 090328: Updated position/optical afterglow candidate
  97. GRB 090328: Possible Swift/XRT detection
  98. Fermi LAT and GBM detections of GRB090328
  99. GRB 090323: Radio afterglow detection
  100. GRB 090323: Additional Lick observations

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