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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"

27045 results found.

  1. GRB 090423 limiting magnitudes
  2. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  3. GRB 090423: GROND detection and preliminary photo-z
  4. GRB 090423: NOT z-band limit
  5. GRB 090423: Swift-XRT refined analysis
  6. GRB090418A Rc-band photometry
  7. GRB090423 - Swift/UVOT upper limits.
  8. GRB 090422: Swift-XRT refined analysis
  9. GRB090423, RIMOTS optical upper limits
  10. GRB 090423: Swift-BAT refined analysis
  11. GRB 090422: Swift/UVOT Upper Limits
  12. GRB 090423: Faulkes Telescope South observations
  13. GRB 090423: Swift detection of a burst
  14. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  15. GRB 090422: Swift-BAT refined analysis
  16. GRB 080410: GAO 150cm telescope Optical Observation
  17. GRB 080408A: GAO 150cm telescope Optical Observation
  18. GRB 090422: Liverpool Telescope observations
  19. GRB 090418B: Suzaku WAM observation of the prompt emission
  20. GRB 090422: Swift detection of a burst
  21. GRB 090418C: Fermi GBM Detection
  22. Swift-BAT trigger 349718 is not a burst
  23. GRB 090419: Swift/UVOT Observations
  24. GRB 090418A: Swift/UVOT Observations
  25. GRB 090417B: Swift/UVOT Upper Limits
  26. GRB 090419: Swift-XRT refined analysis
  27. GRB 090419: GROND detection of afterglow candidate
  28. GRB 090419: Swift-BAT refined analysis
  29. GRB 090418: Swift XRT refined analysis
  30. GRB 090418A: ROTSE-III Refined Analysis
  31. GRB 090419: Swift detection of a burst
  32. GRB 090418: Swift-BAT refined analysis
  33. GRB 090417B: Swift-XRT refined analysis
  34. GRB 090417B: Swift-BAT further refined analysis
  35. GRB 090418: PAIRITEL NIR detection
  36. GRB 090418 Lick Redshift
  37. GRB 090418: ROTSE-III Confirmation of Optical Counterpart
  38. GRB 090418: Swift detection of a burst with optical afterglow
  39. GRB 090411B: Suzaku WAM observation of the prompt emission
  40. GRB 090411A: Suzaku WAM observation of the prompt emission
  41. GRB 090417B: Swift-BAT refined analysis
  42. GRB 090417A: Swift-BAT refined analysis
  43. GRB 090417B: Swift detection of a burst
  44. GRB 090417: Swift detection of a short burst
  45. GRB 090412: Fermi GBM detection
  46. GRB 090411B: Fermi GBM detection
  47. GRB 090411A: Fermi GBM detection
  48. GRB 090410: Suzaku WAM observation of the prompt emission
  49. Fermi GBM trigger 261106787 is not a GRB
  50. GRB 090410: Swift-BAT refined analysis
  51. GRB 090410: Swift detection of a burst
  52. GRB 090409: Fermi GBM detection
  53. Swift-BAT Trigger 348781 is not a GRB
  54. Swift-BAT Trigger 348720 is not a GRB
  55. GRB090408, RIMOTS optical upper limits
  56. GRB 090408: Xinglong TNT optical Upper Limit
  57. Swift-BAT trigger 348781: almost certainly not a burst
  58. Fermi GBM Detection of a weak source
  59. GRB 090408B: MASTER II-Kourovka optical observations
  60. GRB 090408: Swift detection of a burst
  61. GRB 090407: Swift-XRT refined analysis
  62. GRB 090407: Swift UVOT Upper Limits
  63. GRB 090407: Swift-BAT refined analysis
  64. GRB 090407: ROTSE-III Optical Limits
  65. GRB 090407: Swift detection of a burst
  66. GRB 090405: Fermi GBM Detection
  67. GRB 090403: Fermi GBM detection
  68. Swift/UVOT observations of GRB090404
  69. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  70. GRB 090404: Swift-XRT Team refined analysis
  71. GRB 090404: Xinglong TNT optical Upper Limit
  72. GRB 090404: Swift-BAT refined analysis
  73. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  74. GRB 090404: Swift detection of a burst
  75. GRB 090401A: Suzaku WAM observation of the prompt emission
  76. GRB 090401B: Suzaku WAM observation of the prompt emission
  77. Konus-Wind observation of GRB 090401B
  78. GRB 090401B: Xinglong TNT optical Upper Limit
  79. GRB090401B, RIMOTS optical upper limits
  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: Swift-BAT refined analysis
  88. GRB 090401B: Swift detection of a burst
  89. GRB 090401, Swift-BAT refined analysis
  90. GRB 090323: Further TLS detections - a break?
  91. GRB 090401: Swift detection of a burst
  92. GRB 090324: Suzaku WAM observation of the prompt emission
  93. GRB 090326: Fermi GBM detection
  94. GRB 090328B: Fermi GBM Detection
  95. GRB 090330: Fermi GBM detection
  96. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  97. GRB 090328: Swift XRT refined analysis
  98. Konus-Wind observation of GRB 090328
  99. GRB 090328: Swift UVOT observations
  100. Fermi LAT and GBM detections of GRB090328

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