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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"

26764 results found.

  1. GRB 051016A: Swift/UVOT upper limits
  2. GRB 051016B: Swift/UVOT detection
  3. GRB 051016B: Refined analysis of the Swift-BAT burst
  4. GRB 051016B: Swift detection of a soft burst
  5. GRB 051016: Swift-BAT refined analysis
  6. GRB051016: Swift detection of a burst
  7. GRB 051012: Swift-BAT detection of burst yesterday
  8. Swift trigger 159578 is not a burst
  9. Swift-BAT Trigger 159578 is a possible burst
  10. GRB050805A: Rc optical observations
  11. GRB 051006: Swift/UVOT Upper Limits
  12. GRB051008: Swift XRT refined analysis
  13. GRB051008 - Swift UVOT upper limits
  14. Konus-Wind observation of GRB 051008
  15. GRB051008: Final refined analysis of the Swift-BAT burst
  16. GRB051008: Refined analysis of the Swift-BAT burst
  17. GRB051008: Radio Observation
  18. GRB 051008: Swift XRT position
  19. GRB 051008: early Swift XRT analysis
  20. GRB 051008: Swift UVOT Candidate
  21. GRB051008: Swift-BAT detection of a bright burst
  22. GRB 051006: XRT refined analysis
  23. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  24. GRB 051006: optical observations at Sierra Nevada
  25. GRB051006: Refined analysis of the Swift-BAT burst
  26. GRB 051006: XRT position
  27. GRB051006: Swift detection of a burst
  28. GRB 050906, summary of radio observations
  29. Swift-BAT triggers 158261 and 158262 Retraction
  30. GRB051001: Swift UVOT Upper Limits
  31. GRB 050925: Second Epoch WSRT Radio Observations
  32. GRB 051001: Swift XRT refined analysis
  33. GRB 051001: I-band limit
  34. GRB 051001: AAT infra-red observations
  35. GRB 051001: Swift-BAT refined analysis
  36. GRB 051001: Swift Detection of a Burst
  37. GRB 051001: ROTSE-III Optical Limits
  38. GRB050922C: UVES/VLT high resolution spectroscopy
  39. GRB050925: Swift/XRT limits
  40. GRB050922C - Swift UVOT preliminary analysis
  41. GRB 050925: WSRT Radio Observations
  42. GRB050925: Swift UVOT upper limits
  43. Refined analysis of the Swift-BAT soft short burst
  44. GRB050925: Faulkes Telescope North R-band limit
  45. GRB050925: Swift-BAT detection of a short burst
  46. GRB 050922B: Correction to BAT refined analysis, longer burst
  47. GRB050922C: TNG spectroscopic observations
  48. GRB050922B: refined XRT analysis
  49. Konus-Wind observation of GRB 050922C
  50. GRB050922B: Swift UVOT early upper limits.
  51. GRB OT observation
  52. GRB050922C: observation at MonteBoo
  53. GRB 050922B: optical limit
  54. GRB 050922C: Swift XRT refined analysis
  55. HETE Fregate observations of GRB 050922C
  56. GRB 050922C: Swift-BAT refined analysis
  57. GRB 050922B: Swift-BAT refined analysis
  58. GRB050922C: optical observations
  59. GRB 050922C: optical obserations
  60. GRB 050922C: NOT optical observations
  61. GRB 050922C: Swift detection of a bright burst
  62. GRB 050922C: ROTSE-IIId Refined Analysis
  63. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  64. GRB 050922B: ROTSE-III Optical Limits
  65. GRB 050922B,optical observation
  66. GRB050922B: Swift-BAT detection of a weak long burst
  67. Possible GRB 050922 detected by INTEGRAL
  68. GRB050916: Swift/UVOT Upper Limits
  69. GRB 050916: Swift-BAT refined analysis
  70. Swift-BAT trigger 155764 is not a GRB
  71. Swift-BAT trigger 155764 is probably not a GRB
  72. Swift trigger 155764: bad XRT centroid
  73. Swift-BAT trigger 155535 is definitely not a GRB
  74. GRB050916 : Swift-XRT refined analysis
  75. GRB 050916: XRT position
  76. GRB 050915B: Swift-BAT refined analysis
  77. GRB 050915B: Swift/UVOT Upper Limits
  78. GRB050916: Swift-BAT detection of a long weak burst
  79. GRB 050915B: XRT position
  80. GRB050915B: Swift-BAT detection of a long bright burst
  81. GRB050915: Swift/UVOT upper limits
  82. GRB 050915: KAIT optical limit
  83. GRB 050915: IR Observations
  84. GRB 050915: Swift XRT refined analysis
  85. GRB 050915: Swift-BAT refined analysis
  86. GRB050915: XRT position
  87. GRB 050915: ROTSE-III optical limits
  88. GRB 050915: Swift detection of a GRB
  89. GRB050911: Upper limit on X-ray afterglow
  90. Swift-BAT trigger 155072 ground analysis
  91. Swift-BAT trigger 155072 is probably not a GRB
  92. GRB050914: XRT position probably due to cosmic ray
  93. Swift is in normal operation
  94. GRB050911: Swift UVOT followup observations
  95. GRB050911: Swift-XRT position
  96. GRB 050911: LCO observations
  97. GRB 050911, optical observations
  98. GRB 050911: Swift-BAT refined analysis
  99. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  100. GRB050911: Swift-BAT detection of a long burst

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