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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"

21458 results found.

  1. GRB 050922C: Swift detection of a bright burst
  2. GRB 050922C: ROTSE-IIId Refined Analysis
  3. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  4. GRB 050922B: ROTSE-III Optical Limits
  5. GRB 050922B,optical observation
  6. GRB050922B: Swift-BAT detection of a weak long burst
  7. GRB050918: Possible Swift/XRT detected afterglow
  8. GRB050820B: analysis of the XMM-Newton observation
  9. GRB050916: Swift/UVOT Upper Limits
  10. GRB 050916: Swift-BAT refined analysis
  11. GRB 050915a: Radio Observations
  12. Swift-BAT trigger 155764 is not a GRB
  13. Swift-BAT trigger 155764 is probably not a GRB
  14. Swift trigger 155764: bad XRT centroid
  15. Swift-BAT trigger 155535 is definitely not a GRB
  16. GRB050916 : Swift-XRT refined analysis
  17. GRB 050916: XRT position
  18. GRB 050915b, SMARTS optical/IR observations of the XRT position
  19. GRB 050915B: Swift-BAT refined analysis
  20. GRB 050915B: Swift/UVOT Upper Limits
  21. GRB050916: Swift-BAT detection of a long weak burst
  22. GRB 050915a: IR Transient
  23. GRB 050915B: XRT position
  24. GRB050915B: Swift-BAT detection of a long bright burst
  25. GRB050915: Swift/UVOT upper limits
  26. GRB 050915: KAIT optical limit
  27. GRB 050915: IR Observations
  28. GRB 050915: Swift XRT refined analysis
  29. GRB 050915: Swift-BAT refined analysis
  30. GRB050915: P60 Optical Observations
  31. GRB050915, optical observations
  32. GRB050915: XRT position
  33. GRB 050915: ROTSE-III optical limits
  34. GRB 050915: Swift detection of a GRB
  35. GRB050911: Upper limit on X-ray afterglow
  36. Swift-BAT trigger 155072 ground analysis
  37. Swift-BAT trigger 155072 is probably not a GRB
  38. GRB050914: XRT position probably due to cosmic ray
  39. GRB 050911: LCO limits on a variable source
  40. Swift is in normal operation
  41. GRB050911: Swift UVOT followup observations
  42. GRB 050911, optical content of Swift/XRT error box
  43. GRB050911: Swift-XRT position
  44. GRB 050911, optical observations
  45. GRB 050911: Swift-BAT refined analysis
  46. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  47. GRB050911: Swift-BAT detection of a long burst
  48. GRB050908: detection of Swift/UVOT optical counterpart
  49. RBO GRB 050908 observations
  50. WIRO observations in I of GRB 050908
  51. GRB 050906: Possible X-ray Counterpart
  52. GRB050908: Swift/UVOT Early upper limits
  53. GRB050908 : Swift-XRT refined analysis
  54. GRB 050908: Swift-BAT refined analysis
  55. GRB 050908: Optical observations
  56. Gemini Spectroscopy of GRB 050908
  57. GRB 050908 : Swift XRT position
  58. GRB 050908: KAIT observations
  59. GRB 050908: P60 Confirmation of Optical Afterglow
  60. GRB 050908: Swift detection of a burst
  61. Swift trigger 154073 is not a GRB
  62. GRB050904: CrAO optical observations
  63. GRB 050904 BAT refined analysis of complete data set
  64. GRB 050906: MARGE Optical Limits
  65. GRB 050906: Swift-BAT refined analysis
  66. GRB 050906: Swift XRT upper limit
  67. GRB050906: P60 Observations
  68. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  69. GRB 050906: Bright galaxy in BAT error box
  70. GRB 050906: Swift/BAT Detection of a possible burst
  71. GRB 050904: Swift/UVOT observations
  72. GRB 050904: NIR object inside the XRT error box
  73. GRB 050904: early Swift XRT analysis results
  74. GRB 050904: BAT refined analysis of partial data set
  75. GRB 050904: SOAR/PROMPT Observations
  76. GRB050904: P60 Observations
  77. GRB 050904: TAROT optical limits
  78. GRB050904: Swift-BAT detection of a probable burst
  79. Swift-BAT triggers 153461-153465 are not GRBs
  80. Retraction of Swift-BAT trigger #153355
  81. GRB 050824: MDM Observations
  82. GRB 050827: Swift XRT preliminary analysis results
  83. Swift Trigger #152652 is not a GRB
  84. GRB 050827 : OSN 1.5m optical observations
  85. GRB 050827: P200 NIR Observations
  86. GRB050827: Swift/UVOT upper limits
  87. GRB 050827: Optical Limit
  88. GRB 050827: XRT possible afterglow detection
  89. GRB 050826 : Lulin R band observation
  90. GRB050827: RTT150 optical observations
  91. GRB 050827: Swift-BAT refined analysis
  92. GRB050827: Swift-BAT detection of a burst
  93. GRB 050826: Optical Candidate
  94. GRB050824, HETE-2 Observation
  95. GRB 050826: Swift XRT preliminary analysis results
  96. GRB 050826: BAT refined analysis
  97. GRB050826: Swift/UVOT early upper limits
  98. GRB050824: First 2 hours of power low optical decay?
  99. GRB 050826: Swift XRT position
  100. GRB050826: Swift-BAT detection of a long burst

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