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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"

21467 results found.

  1. GRB 050922C: Swift XRT refined analysis
  2. HETE Fregate observations of GRB 050922C
  3. GRB 050922C: Swift-BAT refined analysis
  4. GRB 050922B: Swift-BAT refined analysis
  5. GRB050922C: optical observations
  6. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  7. GRB 050922C: optical obserations
  8. GRB 050922C: NOT optical observations
  9. GRB 050922A: Analysis of Swift/XRT TOO observation
  10. GRB 050922C: Swift detection of a bright burst
  11. GRB 050922C: ROTSE-IIId Refined Analysis
  12. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  13. GRB 050922B: ROTSE-III Optical Limits
  14. GRB 050922B,optical observation
  15. GRB050922B: Swift-BAT detection of a weak long burst
  16. GRB050918: Possible Swift/XRT detected afterglow
  17. GRB050820B: analysis of the XMM-Newton observation
  18. GRB050916: Swift/UVOT Upper Limits
  19. GRB 050916: Swift-BAT refined analysis
  20. GRB 050915a: Radio Observations
  21. Swift-BAT trigger 155764 is not a GRB
  22. Swift-BAT trigger 155764 is probably not a GRB
  23. Swift trigger 155764: bad XRT centroid
  24. Swift-BAT trigger 155535 is definitely not a GRB
  25. GRB050916 : Swift-XRT refined analysis
  26. GRB 050916: XRT position
  27. GRB 050915b, SMARTS optical/IR observations of the XRT position
  28. GRB 050915B: Swift-BAT refined analysis
  29. GRB 050915B: Swift/UVOT Upper Limits
  30. GRB050916: Swift-BAT detection of a long weak burst
  31. GRB 050915a: IR Transient
  32. GRB 050915B: XRT position
  33. GRB050915B: Swift-BAT detection of a long bright burst
  34. GRB050915: Swift/UVOT upper limits
  35. GRB 050915: KAIT optical limit
  36. GRB 050915: IR Observations
  37. GRB 050915: Swift XRT refined analysis
  38. GRB 050915: Swift-BAT refined analysis
  39. GRB050915: P60 Optical Observations
  40. GRB050915, optical observations
  41. GRB050915: XRT position
  42. GRB 050915: ROTSE-III optical limits
  43. GRB 050915: Swift detection of a GRB
  44. GRB050911: Upper limit on X-ray afterglow
  45. Swift-BAT trigger 155072 ground analysis
  46. Swift-BAT trigger 155072 is probably not a GRB
  47. GRB050914: XRT position probably due to cosmic ray
  48. GRB 050911: LCO limits on a variable source
  49. Swift is in normal operation
  50. GRB050911: Swift UVOT followup observations
  51. GRB 050911, optical content of Swift/XRT error box
  52. GRB050911: Swift-XRT position
  53. GRB 050911, optical observations
  54. GRB 050911: Swift-BAT refined analysis
  55. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  56. GRB050911: Swift-BAT detection of a long burst
  57. GRB050908: detection of Swift/UVOT optical counterpart
  58. RBO GRB 050908 observations
  59. WIRO observations in I of GRB 050908
  60. GRB 050906: Possible X-ray Counterpart
  61. GRB050908: Swift/UVOT Early upper limits
  62. GRB050908 : Swift-XRT refined analysis
  63. GRB 050908: Swift-BAT refined analysis
  64. GRB 050908: Optical observations
  65. Gemini Spectroscopy of GRB 050908
  66. GRB 050908 : Swift XRT position
  67. GRB 050908: KAIT observations
  68. GRB 050908: P60 Confirmation of Optical Afterglow
  69. GRB 050908: Swift detection of a burst
  70. Swift trigger 154073 is not a GRB
  71. GRB050904: CrAO optical observations
  72. GRB 050904 BAT refined analysis of complete data set
  73. GRB 050906: MARGE Optical Limits
  74. GRB 050906: Swift-BAT refined analysis
  75. GRB 050906: Swift XRT upper limit
  76. GRB050906: P60 Observations
  77. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  78. GRB 050906: Bright galaxy in BAT error box
  79. GRB 050906: Swift/BAT Detection of a possible burst
  80. GRB 050904: Swift/UVOT observations
  81. GRB 050904: NIR object inside the XRT error box
  82. GRB 050904: early Swift XRT analysis results
  83. GRB 050904: BAT refined analysis of partial data set
  84. GRB 050904: SOAR/PROMPT Observations
  85. GRB050904: P60 Observations
  86. GRB 050904: TAROT optical limits
  87. GRB050904: Swift-BAT detection of a probable burst
  88. Swift-BAT triggers 153461-153465 are not GRBs
  89. Retraction of Swift-BAT trigger #153355
  90. GRB 050824: MDM Observations
  91. GRB 050827: Swift XRT preliminary analysis results
  92. Swift Trigger #152652 is not a GRB
  93. GRB 050827 : OSN 1.5m optical observations
  94. GRB 050827: P200 NIR Observations
  95. GRB050827: Swift/UVOT upper limits
  96. GRB 050827: Optical Limit
  97. GRB 050827: XRT possible afterglow detection
  98. GRB 050826 : Lulin R band observation
  99. GRB050827: RTT150 optical observations
  100. GRB 050827: Swift-BAT refined analysis

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