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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"

19353 results found.

  1. GRB 050922B,optical observation
  2. GRB050922B: Swift-BAT detection of a weak long burst
  3. GRB050918: Possible Swift/XRT detected afterglow
  4. GRB050820B: analysis of the XMM-Newton observation
  5. GRB050916: Swift/UVOT Upper Limits
  6. GRB 050916: Swift-BAT refined analysis
  7. Swift-BAT trigger 155764 is not a GRB
  8. Swift-BAT trigger 155764 is probably not a GRB
  9. Swift trigger 155764: bad XRT centroid
  10. Swift-BAT trigger 155535 is definitely not a GRB
  11. GRB050916 : Swift-XRT refined analysis
  12. GRB 050916: XRT position
  13. GRB 050915B: Swift-BAT refined analysis
  14. GRB 050915B: Swift/UVOT Upper Limits
  15. GRB050916: Swift-BAT detection of a long weak burst
  16. GRB 050915B: XRT position
  17. GRB050915B: Swift-BAT detection of a long bright burst
  18. GRB050915: Swift/UVOT upper limits
  19. GRB 050915: KAIT optical limit
  20. GRB 050915: IR Observations
  21. GRB 050915: Swift XRT refined analysis
  22. GRB 050915: Swift-BAT refined analysis
  23. GRB050915, optical observations
  24. GRB050915: XRT position
  25. GRB 050915: ROTSE-III optical limits
  26. GRB 050915: Swift detection of a GRB
  27. GRB050911: Upper limit on X-ray afterglow
  28. Swift-BAT trigger 155072 ground analysis
  29. Swift-BAT trigger 155072 is probably not a GRB
  30. GRB050914: XRT position probably due to cosmic ray
  31. Swift is in normal operation
  32. GRB050911: Swift UVOT followup observations
  33. GRB 050911, optical content of Swift/XRT error box
  34. GRB050911: Swift-XRT position
  35. GRB 050911, optical observations
  36. GRB 050911: Swift-BAT refined analysis
  37. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  38. GRB050911: Swift-BAT detection of a long burst
  39. GRB050908: detection of Swift/UVOT optical counterpart
  40. RBO GRB 050908 observations
  41. WIRO observations in I of GRB 050908
  42. GRB 050906: Possible X-ray Counterpart
  43. GRB050908: Swift/UVOT Early upper limits
  44. GRB050908 : Swift-XRT refined analysis
  45. GRB 050908: Swift-BAT refined analysis
  46. GRB 050908: Optical observations
  47. Gemini Spectroscopy of GRB 050908
  48. GRB 050908 : Swift XRT position
  49. GRB 050908: KAIT observations
  50. GRB 050908: P60 Confirmation of Optical Afterglow
  51. GRB 050908: Swift detection of a burst
  52. Swift trigger 154073 is not a GRB
  53. GRB050904: CrAO optical observations
  54. GRB 050904 BAT refined analysis of complete data set
  55. GRB 050906: MARGE Optical Limits
  56. GRB 050906: Swift-BAT refined analysis
  57. GRB 050906: Swift XRT upper limit
  58. GRB050906: P60 Observations
  59. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  60. GRB 050906: Bright galaxy in BAT error box
  61. GRB 050906: Swift/BAT Detection of a possible burst
  62. GRB 050904: Swift/UVOT observations
  63. GRB 050904: early Swift XRT analysis results
  64. GRB 050904: BAT refined analysis of partial data set
  65. GRB050904: P60 Observations
  66. GRB 050904: TAROT optical limits
  67. GRB050904: Swift-BAT detection of a probable burst
  68. Swift-BAT triggers 153461-153465 are not GRBs
  69. Retraction of Swift-BAT trigger #153355
  70. GRB 050824: MDM Observations
  71. GRB 050827: Swift XRT preliminary analysis results
  72. Swift Trigger #152652 is not a GRB
  73. GRB050827: Swift/UVOT upper limits
  74. GRB 050827: Optical Limit
  75. GRB 050827: XRT possible afterglow detection
  76. GRB050827: RTT150 optical observations
  77. GRB 050827: Swift-BAT refined analysis
  78. GRB050827: Swift-BAT detection of a burst
  79. GRB 050826: Optical Candidate
  80. GRB050824, HETE-2 Observation
  81. GRB 050826: Swift XRT preliminary analysis results
  82. GRB 050826: BAT refined analysis
  83. GRB050826: Swift/UVOT early upper limits
  84. GRB050824: First 2 hours of power low optical decay?
  85. GRB 050826: Swift XRT position
  86. GRB050826: Swift-BAT detection of a long burst
  87. GRB050824: MASTER final analysis of the OT observations
  88. Possible GRB050825:MASTER optical observations
  89. Swift-BAT trigger 152038 is definitely not a GRB
  90. GRB050824: CORRECTION to UVOT observing times
  91. Swift-BAT trigger 152038 is probably not a GRB
  92. GRB050824: Swift/UVOT detection of fading afterglow
  93. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  94. GRB050824, I-band imaging
  95. GRB 050822: refined XRT analysis
  96. GRB 050824: XRT refined analysis and possible afterglow detection
  97. GRB 050824: BAT refined analysis of a soft weak burst
  98. GRB050824: MASTER:OT decay
  99. GRB050824: MASTER observation OT
  100. GRB050805a: MASTER optical candidat

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