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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"

19591 results found.

  1. GRB 051006: XRT position
  2. GRB051006: Swift detection of a burst
  3. Swift-BAT triggers 158261 and 158262 Retraction
  4. GRB051001: Swift UVOT Upper Limits
  5. GRB 050925: Second Epoch WSRT Radio Observations
  6. GRB 051001: Swift XRT refined analysis
  7. GRB 051001, optical observations at Mt. John
  8. GRB 051001: I-band limit
  9. GRB 051001: Swift-BAT refined analysis
  10. GRB 051001: Swift Detection of a Burst
  11. GRB 051001: ROTSE-III Optical Limits
  12. GRB050922B: optical limit
  13. GRB050925: Swift/XRT limits
  14. GRB/SGR 050925: IR Observations
  15. GRB050922C - Swift UVOT preliminary analysis
  16. GRB 050925: WSRT Radio Observations
  17. GRB050925: Swift UVOT upper limits
  18. Refined analysis of the Swift-BAT soft short burst
  19. GRB050925: Faulkes Telescope North R-band limit
  20. GRB050925: Swift-BAT detection of a short burst
  21. GRB 050922B: Correction to BAT refined analysis, longer burst
  22. GRB050922B: refined XRT analysis
  23. Konus-Wind observation of GRB 050922C
  24. GRB050922B: Swift UVOT early upper limits.
  25. GRB 050922B: optical limit
  26. GRB 050922C: Swift XRT refined analysis
  27. HETE Fregate observations of GRB 050922C
  28. GRB 050922C: Swift-BAT refined analysis
  29. GRB 050922B: Swift-BAT refined analysis
  30. GRB050922C: optical observations
  31. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  32. GRB 050922C: optical obserations
  33. GRB 050922C: NOT optical observations
  34. GRB 050922A: Analysis of Swift/XRT TOO observation
  35. GRB 050922C: Swift detection of a bright burst
  36. GRB 050922C: ROTSE-IIId Refined Analysis
  37. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  38. GRB 050922B: ROTSE-III Optical Limits
  39. GRB 050922B,optical observation
  40. GRB050922B: Swift-BAT detection of a weak long burst
  41. GRB050918: Possible Swift/XRT detected afterglow
  42. GRB050820B: analysis of the XMM-Newton observation
  43. GRB050916: Swift/UVOT Upper Limits
  44. GRB 050916: Swift-BAT refined analysis
  45. Swift-BAT trigger 155764 is not a GRB
  46. Swift-BAT trigger 155764 is probably not a GRB
  47. Swift trigger 155764: bad XRT centroid
  48. Swift-BAT trigger 155535 is definitely not a GRB
  49. GRB050916 : Swift-XRT refined analysis
  50. GRB 050916: XRT position
  51. GRB 050915B: Swift-BAT refined analysis
  52. GRB 050915B: Swift/UVOT Upper Limits
  53. GRB050916: Swift-BAT detection of a long weak burst
  54. GRB 050915B: XRT position
  55. GRB050915B: Swift-BAT detection of a long bright burst
  56. GRB050915: Swift/UVOT upper limits
  57. GRB 050915: KAIT optical limit
  58. GRB 050915: IR Observations
  59. GRB 050915: Swift XRT refined analysis
  60. GRB 050915: Swift-BAT refined analysis
  61. GRB050915, optical observations
  62. GRB050915: XRT position
  63. GRB 050915: ROTSE-III optical limits
  64. GRB 050915: Swift detection of a GRB
  65. GRB050911: Upper limit on X-ray afterglow
  66. Swift-BAT trigger 155072 ground analysis
  67. Swift-BAT trigger 155072 is probably not a GRB
  68. GRB050914: XRT position probably due to cosmic ray
  69. Swift is in normal operation
  70. GRB050911: Swift UVOT followup observations
  71. GRB 050911, optical content of Swift/XRT error box
  72. GRB050911: Swift-XRT position
  73. GRB 050911, optical observations
  74. GRB 050911: Swift-BAT refined analysis
  75. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  76. GRB050911: Swift-BAT detection of a long burst
  77. GRB050908: detection of Swift/UVOT optical counterpart
  78. RBO GRB 050908 observations
  79. WIRO observations in I of GRB 050908
  80. GRB 050906: Possible X-ray Counterpart
  81. GRB050908: Swift/UVOT Early upper limits
  82. GRB050908 : Swift-XRT refined analysis
  83. GRB 050908: Swift-BAT refined analysis
  84. GRB 050908: Optical observations
  85. Gemini Spectroscopy of GRB 050908
  86. GRB 050908 : Swift XRT position
  87. GRB 050908: KAIT observations
  88. GRB 050908: P60 Confirmation of Optical Afterglow
  89. GRB 050908: Swift detection of a burst
  90. Swift trigger 154073 is not a GRB
  91. GRB050904: CrAO optical observations
  92. GRB 050904 BAT refined analysis of complete data set
  93. GRB 050906: MARGE Optical Limits
  94. GRB 050906: Swift-BAT refined analysis
  95. GRB 050906: Swift XRT upper limit
  96. GRB050906: P60 Observations
  97. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  98. GRB 050906: Bright galaxy in BAT error box
  99. GRB 050906: Swift/BAT Detection of a possible burst
  100. GRB 050904: Swift/UVOT observations

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