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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"

27046 results found.

  1. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  2. GRB051109B: XRT position
  3. GRB 051109B: Super-LOTIS Observations
  4. GRB 051109B Kiso optical follow-up observation
  5. GRB 051109B: Swift detection of a burst
  6. GRB 051109: HET Optical Spectrum and Absorption Redshift
  7. GRB051109: Early Super-LOTIS Detection
  8. GRB 051109: Swift-BAT refined analysis
  9. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  10. GRB051109: Swift detection of a burst
  11. GRB 051109a: IR Detections
  12. GRB 051109: ROTSE-III Detection of Possible Counterpart
  13. GRB051105B: Swift/XRT upper limit
  14. GRB051105B: Swift/UVOT upper limit
  15. GRB051103: optical observations
  16. GRB051028: Swift-XRT refined analysis
  17. GRB051105A: Swift/UVOT Observations
  18. XRT observations of GRB 051105A
  19. GRB 051105b: ART optical limits
  20. GRB 051105B (INTEGRAL 2701): Optical observation
  21. GRB 051105: Swift-BAT refined analysis
  22. GRB 051105: Swift detection of a short burst
  23. Konus-Wind observation of GRB 051028
  24. GRB051028 SARA Observation
  25. GRB051028: optical observations
  26. GRB051028: Swift/UVOT upper limits
  27. GRB051028: WHT optical candidate
  28. GRB051028: Swift XRT Position
  29. GRB051021B: Swift/UVOT Upper limits
  30. GRB 051021, Optical Observations
  31. GRB051012: Swift-XRT analysis
  32. GRB051021B: Swift XRT refined analysis
  33. GRB 051022, mm counterpart
  34. GRB 051022: Swift/UVOT Upper Limits
  35. Konus-Wind observation of GRB 051022
  36. GRB051022: Swift XRT Position
  37. GRB 051022 (=H3950): SXC Flight Localization is Valid
  38. GRB051021: Swift/UVOT Upper Limits
  39. GRB 051021B: Refined analysis of the Swift-BAT burst
  40. GRB051022,optical observation
  41. GRB 051022A: ROTSE-III Optical Limits
  42. GRB 051022: Optical observations
  43. GRB 051021,optical observation
  44. GRB051021B: Swift XRT Position
  45. GRB 051021B: Swift detection of a burst
  46. GRB051021: Swift XRT analysis
  47. GRB051021 (=H3947): Refined Analysis
  48. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  49. Swift-BAT trigger 160640 is not a real GRB
  50. GRB051021: A GRB Localized by HETE
  51. Swift-BAT trigger 160619 is not a GRB
  52. Swift-BAT triggered on a posible CR Shower or possible GRB
  53. GRB 051016b: Optical limit
  54. GRB 051016A: Swift/UVOT upper limits
  55. GRB 051016B: Swift/UVOT detection
  56. GRB 051016B: Refined analysis of the Swift-BAT burst
  57. GRB 051016B: Swift detection of a soft burst
  58. GRB 051016: Swift-BAT refined analysis
  59. GRB051016: Swift detection of a burst
  60. GRB 051012: Swift-BAT detection of burst yesterday
  61. Swift trigger 159578 is not a burst
  62. Swift-BAT Trigger 159578 is a possible burst
  63. GRB050805A: Rc optical observations
  64. GRB 051006: Swift/UVOT Upper Limits
  65. GRB051008: Swift XRT refined analysis
  66. GRB051008 - Swift UVOT upper limits
  67. Konus-Wind observation of GRB 051008
  68. GRB051008: Final refined analysis of the Swift-BAT burst
  69. GRB051008: Refined analysis of the Swift-BAT burst
  70. GRB 051008: Swift XRT position
  71. GRB 051008: early Swift XRT analysis
  72. GRB 051008: Swift UVOT Candidate
  73. GRB051008: Swift-BAT detection of a bright burst
  74. GRB 051006: XRT refined analysis
  75. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  76. GRB051006: Refined analysis of the Swift-BAT burst
  77. GRB 051006: XRT position
  78. GRB051006: Swift detection of a burst
  79. GRB051001: Swift UVOT Upper Limits
  80. GRB 051001: Swift XRT refined analysis
  81. GRB 051001: I-band limit
  82. GRB 051001: AAT infra-red observations
  83. GRB 051001: Swift-BAT refined analysis
  84. GRB 051001: Swift Detection of a Burst
  85. GRB 051001: ROTSE-III Optical Limits
  86. GRB050922C: UVES/VLT high resolution spectroscopy
  87. GRB050925: Swift/XRT limits
  88. GRB050922C - Swift UVOT preliminary analysis
  89. GRB050925: Swift UVOT upper limits
  90. Refined analysis of the Swift-BAT soft short burst
  91. GRB050925: Faulkes Telescope North R-band limit
  92. GRB050925: Swift-BAT detection of a short burst
  93. GRB050922C: TNG spectroscopic observations
  94. GRB050922B: refined XRT analysis
  95. Konus-Wind observation of GRB 050922C
  96. GRB050922B: Swift UVOT early upper limits.
  97. GRB OT observation
  98. GRB050922C: observation at MonteBoo
  99. GRB 050922B: optical limit
  100. GRB 050922C: Swift XRT refined analysis

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