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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 081204 : a long GRB localized by INTEGRAL
  2. VLA Radio upper limit on GRB 081203A
  3. Swift-XRT observations of GRB 081203B
  4. Konus-Wind observation of GRB 081203A
  5. Konus-Wind observation of GRB 081203B
  6. GRB081203A: Swift-XRT refined analysis
  7. GRB 081203B: optical observations
  8. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  9. Swift/UVOT detection of GRB081203B
  10. GRB 081203B: Swift-XRT candidate afterglow.
  11. GRB 081203A: optical observations
  12. Swift UVOT observations of GRB 081203A
  13. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  14. GRB081203A: Swift/UVOT grism redshift
  15. GRB 081203A: Burst detection from Swift-BAT slew data
  16. GRB 081203A: Swift-BAT refined analysis
  17. GRB 081203: Enhanced Swift-XRT position
  18. GRB 081130B: MASTER prompt optical observations
  19. GRB081203: optical observation
  20. GRB 081203: Swift detection of a burst with a bright optical counterpart
  21. GRB 081128: optical observation
  22. GRB 081130B: Fermi GBM detection
  23. GRB 081130: Fermi GBM detection
  24. Swift Trigger 335971: Swift/UVOT Observations
  25. GRB 081126: afterglow photometry
  26. GRB 081126: Fermi GBM detection
  27. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  28. VLA Radio upper limit on GRB 081126
  29. GRB 081129: Fermi GBM detection
  30. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  31. GRB 081128A: optical observations
  32. Swift Trigger 335971 is probably not a real source
  33. Trigger 335971: Swift possible detection of a burst
  34. GRB081128: Swift/UVOT Upper Limits
  35. SGR 1806-20: Fermi GBM detection.
  36. GRB 081122B: Fermi GBM Detection
  37. GRB 081128: Swift-XRT refined analysis
  38. GRB 081128: Liverpool Telescope afterglow confirmation
  39. GRB081128: optical observations
  40. GRB081128 : Lulin optical follow-ups
  41. GRB 081128: Swift-BAT refined analysis
  42. GRB 081128: Enhanced Swift-XRT position
  43. GRB 081128: Optical observation of xinglong TNT
  44. GRB 081128: Swift detection of a burst
  45. GRB 081126: Swift observations continuing
  46. GRB081126: Afterglow photometry from Crni Vrh
  47. GRB 081126: GRT Optical Observation
  48. GRB 081127: Swift/UVOT Upper Limits
  49. GRB 081127: Swift-XRT refined analysis
  50. GRB 081127: Enhanced Swift-XRT position
  51. GRB 081126: Confirmation of the Optical Afterglow
  52. GRB 081127: Swift-BAT refined analysis
  53. Konus-Wind observation of GRB 081126
  54. GRB 081126: Swift-XRT refined analysis
  55. GRB 081127: Swift detection of a burst
  56. GRB 081126: Swift/UVOT Observations
  57. GRB 081126: optical observations
  58. GRB 081126: Swift-BAT refined analysis
  59. GRB 081126: Enhanced Swift-XRT position
  60. GRB 081126: TAROT Calern observatory optical observations
  61. GRB 081126: Swift detection of a burst
  62. GRB 081125: Fermi GBM detection
  63. GRB 081124: Fermi GBM detection
  64. GRB 081120: Fermi GBM detection
  65. GRB 081118: Fermi GBM detection.
  66. GRB 081122: Fermi GBM detection
  67. Konus-Wind observation of GRB 081121
  68. GRB 081121, SMARTS optical/IR afterglow observations
  69. GRB081121: Fermi GBM detection
  70. Fermi GBM detection of a weak source
  71. GRB081121: Refined Swift/UVOT observations
  72. GRB 081121: Swift-XRT refined analysis
  73. GRB 081121: Magellan Redshift
  74. GRB 081121: Enhanced Swift-XRT position
  75. GRB 081121: GROND observations
  76. GRB 081121: Swift-BAT refined analysis
  77. GRB081121: Swift/UVOT observations
  78. GRB 081121: Swift detection of a burst
  79. GRB 081121: ROTSE-III Detection of Optical Counterpart
  80. GRB081118 : optical upper limit
  81. GRB 081016b, SMARTS optical/IR observations
  82. GRB 081119: Fermi GBM detection
  83. VLA Radio upper limit on GRB 081118
  84. GRB 081118: VLT redshift
  85. GRB 081118: Swift-XRT refined analysis
  86. GRB 081118: GROND detection of afterglow
  87. GRB 081118: optical afterglow candidate
  88. GRB 081118: Swift UVOT Upper Limits
  89. GRB 081118: Swift-BAT refined analysis
  90. GRB 081118: Enhanced Swift-XRT position
  91. GRB 081118: Swift detection of a burst
  92. GRB 081109A: confirmation of possible detection host galaxy
  93. Further Swift-XRT observations of the probable GRB 081105.
  94. GRB 081113: Fermi GBM detection
  95. GRB 081102: RTT150 Optical observations
  96. GRB 081110: Fermi GBM detection
  97. GRB 081110: MASTER: first optical observations Fermi GRB
  98. GRB 081109: TAROT La Silla observatory optical observations
  99. GRB 081102: MASTER refind and final results
  100. GRB 081109: GROND redshift limit and host extinction

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