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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"

21459 results found.

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

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