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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 081203B: optical observations
  2. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  3. Swift/UVOT detection of GRB081203B
  4. GRB 081203B: Swift-XRT candidate afterglow.
  5. GRB 081203A: optical observations
  6. Swift UVOT observations of GRB 081203A
  7. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  8. GRB081203A: Swift/UVOT grism redshift
  9. GRB 081203A: Burst detection from Swift-BAT slew data
  10. GRB 081203A: Swift-BAT refined analysis
  11. GRB 081203: Enhanced Swift-XRT position
  12. GRB 081130B: MASTER prompt optical observations
  13. GRB081203: optical observation
  14. GRB 081203: Swift detection of a burst with a bright optical counterpart
  15. GRB 081128: optical observation
  16. GRB 081130B: Fermi GBM detection
  17. GRB 081130: Fermi GBM detection
  18. Swift Trigger 335971: Swift/UVOT Observations
  19. GRB 081126: afterglow photometry
  20. GRB 081126: Fermi GBM detection
  21. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  22. VLA Radio upper limit on GRB 081126
  23. GRB 081129: Fermi GBM detection
  24. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  25. GRB 081128A: optical observations
  26. Swift Trigger 335971 is probably not a real source
  27. Trigger 335971: Swift possible detection of a burst
  28. GRB081128: Swift/UVOT Upper Limits
  29. SGR 1806-20: Fermi GBM detection.
  30. GRB 081122B: Fermi GBM Detection
  31. GRB 081128: Swift-XRT refined analysis
  32. GRB 081128: Liverpool Telescope afterglow confirmation
  33. GRB081128: optical observations
  34. GRB081128 : Lulin optical follow-ups
  35. GRB 081128: Swift-BAT refined analysis
  36. GRB 081128: Enhanced Swift-XRT position
  37. GRB 081128: Optical observation of xinglong TNT
  38. GRB 081128: Swift detection of a burst
  39. GRB 081126: Swift observations continuing
  40. GRB081126: Afterglow photometry from Crni Vrh
  41. GRB 081126: GRT Optical Observation
  42. GRB 081127: Swift/UVOT Upper Limits
  43. GRB 081127: Swift-XRT refined analysis
  44. GRB 081127: Enhanced Swift-XRT position
  45. GRB 081126: Confirmation of the Optical Afterglow
  46. GRB 081127: Swift-BAT refined analysis
  47. Konus-Wind observation of GRB 081126
  48. GRB 081126: Swift-XRT refined analysis
  49. GRB 081127: Swift detection of a burst
  50. GRB 081126: Swift/UVOT Observations
  51. GRB 081126: optical observations
  52. GRB 081126: Swift-BAT refined analysis
  53. GRB 081126: Enhanced Swift-XRT position
  54. GRB 081126: TAROT Calern observatory optical observations
  55. GRB 081126: Swift detection of a burst
  56. GRB 081125: Fermi GBM detection
  57. GRB 081124: Fermi GBM detection
  58. GRB 081120: Fermi GBM detection
  59. GRB 081118: Fermi GBM detection.
  60. GRB 081122: Fermi GBM detection
  61. Konus-Wind observation of GRB 081121
  62. GRB 081121, SMARTS optical/IR afterglow observations
  63. GRB081121: Fermi GBM detection
  64. Fermi GBM detection of a weak source
  65. GRB081121: Refined Swift/UVOT observations
  66. GRB 081121: Swift-XRT refined analysis
  67. GRB 081121: Magellan Redshift
  68. GRB 081121: Enhanced Swift-XRT position
  69. GRB 081121: GROND observations
  70. GRB 081121: Swift-BAT refined analysis
  71. GRB081121: Swift/UVOT observations
  72. GRB 081121: Swift detection of a burst
  73. GRB 081121: ROTSE-III Detection of Optical Counterpart
  74. GRB081118 : optical upper limit
  75. GRB 081016b, SMARTS optical/IR observations
  76. GRB 081119: Fermi GBM detection
  77. VLA Radio upper limit on GRB 081118
  78. GRB 081118: VLT redshift
  79. GRB 081118: Swift-XRT refined analysis
  80. GRB 081118: GROND detection of afterglow
  81. GRB 081118: optical afterglow candidate
  82. GRB 081118: Swift UVOT Upper Limits
  83. GRB 081118: Swift-BAT refined analysis
  84. GRB 081118: Enhanced Swift-XRT position
  85. GRB 081118: Swift detection of a burst
  86. GRB 081109A: confirmation of possible detection host galaxy
  87. Further Swift-XRT observations of the probable GRB 081105.
  88. GRB 081113: Fermi GBM detection
  89. GRB 081102: RTT150 Optical observations
  90. GRB 081110: Fermi GBM detection
  91. GRB 081110: MASTER: first optical observations Fermi GRB
  92. GRB 081109: TAROT La Silla observatory optical observations
  93. GRB 081102: MASTER refind and final results
  94. GRB 081109: GROND redshift limit and host extinction
  95. GRB 081025: Swift-XRT further analysis
  96. GRB 081024B: Swift-XRT late-time observations
  97. Swift-BAT refined analysis of trigger 334129
  98. GRB 081109B: Swift/UVOT refined analysis
  99. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  100. GRB 081109A: Possible Swift-UVOT detection

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