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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 observation
  2. GRB 090418A: optical observations
  3. GRB 090418B: GROND observations
  4. GRB 090419: Swift/UVOT Observations
  5. GRB 090418B: Faulkes Telescope North observations
  6. GRB 090418A: Swift/UVOT Observations
  7. GRB 090417B: Swift/UVOT Upper Limits
  8. GRB 090417B Correction to the BAT refined analysis position
  9. GRB 090419: Swift-XRT refined analysis
  10. Konus-Wind observation of GRB 090418B
  11. GRB 090418: Erratum in GCN 9168
  12. GRB 090419: GROND detection of afterglow candidate
  13. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  14. GRB 090419: Swift-BAT refined analysis
  15. VLA radio detection of GRB 090418
  16. VLA radio upper limit on GRB 090417B
  17. GRB 090419: Enhanced Swift-XRT position
  18. GRB 090418: Swift XRT refined analysis
  19. GRB 090418A: ROTSE-III Refined Analysis
  20. GRB 090419: Swift detection of a burst
  21. VLA observations of short burst GRB 090417A
  22. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  23. GRB 090417B: Gemini imaging
  24. GRB 090418: Swift-BAT refined analysis
  25. GRB 090417B: Galaxy redshift
  26. GRB 090417B: Swift-XRT refined analysis
  27. GRB 090418: Enhanced Swift-XRT position
  28. GRB 090417B: Swift-BAT further refined analysis
  29. GRB 090418: PAIRITEL NIR detection
  30. GRB 090418 Lick Redshift
  31. GRB 090418: ROTSE-III Confirmation of Optical Counterpart
  32. GRB 090418: Swift detection of a burst with optical afterglow
  33. GRB 090418 OA candidate
  34. GRB 090411B: Suzaku WAM observation of the prompt emission
  35. GRB 090411A: Suzaku WAM observation of the prompt emission
  36. GRB 090417B: Subaru NIR Observations
  37. GRB 090417B: Liverpool Telescope observations
  38. GRB 090417B: MITSuME Okayama optical upper limits
  39. GRB090417B: Xinglong TNT optical upper limit
  40. GRB 090417B: optical observations
  41. GRB090417B: optical observations
  42. GRB 090417B: Swift-BAT refined analysis
  43. GRB 090417A: Swift-BAT refined analysis
  44. GRB 090417A: Early-type nature of the putative host
  45. GRB 090417A: nearby galaxy redshift
  46. GRB 090417B: Swift detection of a burst
  47. GRB 090417: 2MASS galaxy within BAT Localization
  48. GRB 090417: Swift detection of a short burst
  49. GRB 090412: Fermi GBM detection
  50. GRB 090411B: Fermi GBM detection
  51. GRB 090411A: Fermi GBM detection
  52. GRB 090410: Suzaku WAM observation of the prompt emission
  53. GRB 090410: GROND upper limits
  54. Fermi GBM trigger 261106787 is not a GRB
  55. GRB 090410: MITSuME optical upper limits
  56. GRB 090408b: IPN Triangulation
  57. GRB 090328b: IPN Triangulation
  58. GRB 090410: Swift-BAT refined analysis
  59. GRB 090410: Swift detection of a burst
  60. Konus-Wind and Konus-RF observations of GRB 090408b
  61. GRB090408 : TAOS optical observations
  62. GRB 090409: Fermi GBM detection
  63. Swift-BAT Trigger 348781 is not a GRB
  64. Swift-BAT Trigger 348720 is not a GRB
  65. GRB 090406: pseudo-z= 0.91 from prompt emission spectrum
  66. GRB090408, RIMOTS optical upper limits
  67. GRB 090408: Xinglong TNT optical Upper Limit
  68. Swift-BAT trigger 348781: almost certainly not a burst
  69. Fermi GBM Detection of a weak source
  70. GRB 090408B: MASTER II-Kourovka optical observations
  71. GRB 090408: Swift detection of a burst
  72. GRB 090407: GROND upper limits
  73. GRB 090407: VLT observations
  74. GRB 090407: Swift-XRT refined analysis
  75. GRB 090407: Swift UVOT Upper Limits
  76. GRB 090407: Enhanced Swift-XRT position
  77. GRB 090407: Swift-BAT refined analysis
  78. Konus-Wind and Konus-RF observations of GRB 090406
  79. GRB 090407: ROTSE-III Optical Limits
  80. GRB 090407: Swift detection of a burst
  81. GRB 090404: millimeter detection
  82. GRB 090404: nIR observations at Calar Alto
  83. GRB 090405: Fermi GBM Detection
  84. GRB 090403: Fermi GBM detection
  85. GRB 090404: GROND upper limits
  86. GRB 090404: further NOT observations
  87. Swift/UVOT observations of GRB090404
  88. GRB 090404: NOT observations
  89. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  90. GRB 090404: Swift-XRT Team refined analysis
  91. GRB 090404: Xinglong TNT optical Upper Limit
  92. GRB 090404: Swift-BAT refined analysis
  93. GRB 090404: Enhanced Swift-XRT position
  94. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  95. GRB 090404: Swift detection of a burst
  96. GRB 090401A: Suzaku WAM observation of the prompt emission
  97. GRB 090401B: Suzaku WAM observation of the prompt emission
  98. Konus-Wind observation of GRB 090401B
  99. GRB 090401B: Xinglong TNT optical Upper Limit
  100. GRB 090401B: VLA radio upper limit

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