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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"

27408 results found.

  1. GRB 050922B: Swift-BAT refined analysis
  2. GRB050922C: optical observations
  3. GRB 050922C: optical obserations
  4. GRB 050922C: NOT optical observations
  5. GRB 050922C: Swift detection of a bright burst
  6. GRB 050922C: ROTSE-IIId Refined Analysis
  7. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  8. GRB 050922B: ROTSE-III Optical Limits
  9. GRB 050922B,optical observation
  10. GRB050922B: Swift-BAT detection of a weak long burst
  11. Possible GRB 050922 detected by INTEGRAL
  12. GRB050916: Swift/UVOT Upper Limits
  13. GRB 050916: Swift-BAT refined analysis
  14. Swift-BAT trigger 155764 is not a GRB
  15. Swift-BAT trigger 155764 is probably not a GRB
  16. Swift trigger 155764: bad XRT centroid
  17. Swift-BAT trigger 155535 is definitely not a GRB
  18. GRB050916 : Swift-XRT refined analysis
  19. GRB 050916: 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 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: XRT position
  31. GRB 050915: ROTSE-III optical limits
  32. GRB 050915: Swift detection of a GRB
  33. GRB050911: Upper limit on X-ray afterglow
  34. Swift-BAT trigger 155072 ground analysis
  35. Swift-BAT trigger 155072 is probably not a GRB
  36. GRB050914: XRT position probably due to cosmic ray
  37. Swift is in normal operation
  38. GRB050911: Swift UVOT followup observations
  39. GRB050911: Swift-XRT position
  40. GRB 050911: LCO observations
  41. GRB 050911, optical observations
  42. GRB 050911: Swift-BAT refined analysis
  43. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  44. GRB050911: Swift-BAT detection of a long burst
  45. GRB050908: detection of Swift/UVOT optical counterpart
  46. GRB 050910a: TAROT early optical limits
  47. RBO GRB 050908 observations
  48. WIRO observations in I of GRB 050908
  49. GRB 050906: Possible X-ray Counterpart
  50. GRB050908: Swift/UVOT Early upper limits
  51. GRB050908 : Swift-XRT refined analysis
  52. GRB 050908: Swift-BAT refined analysis
  53. GRB 050908: Optical observations
  54. Gemini Spectroscopy of GRB 050908
  55. GRB 050908 : Swift XRT position
  56. GRB 050908: KAIT observations
  57. GRB 050908: Swift detection of a burst
  58. Swift trigger 154073 is not a GRB
  59. GRB 050906: Optical observations at the Very Large Telescope
  60. GRB050904: CrAO optical observations
  61. GRB 050904 BAT refined analysis of complete data set
  62. GRB 050906: MARGE Optical Limits
  63. GRB 050906: Swift-BAT refined analysis
  64. GRB 050906: Swift XRT upper limit
  65. GRB 050906: Radio Observations
  66. GRB050906: P60 Observations
  67. GRB 050906: Bright galaxy in BAT error box
  68. GRB 050906: Swift/BAT Detection of a possible burst
  69. GRB 050904: Swift/UVOT observations
  70. GRB 050904: early Swift XRT analysis results
  71. GRB 050904: BAT refined analysis of partial data set
  72. GRB050904: P60 Observations
  73. GRB 050904: TAROT optical limits
  74. GRB050904: Swift-BAT detection of a probable burst
  75. Swift-BAT triggers 153461-153465 are not GRBs
  76. Retraction of Swift-BAT trigger #153355
  77. Swift Trigger #152652 is not a GRB
  78. GRB050827: Swift/UVOT upper limits
  79. GRB 050827: Optical Limit
  80. GRB 050827: XRT possible afterglow detection
  81. GRB050820A: RTT150 optical observations
  82. GRB050827: RTT150 optical observations
  83. GRB 050827: Swift-BAT refined analysis
  84. GRB050827: Swift-BAT detection of a burst
  85. GRB 050826: Optical Candidate
  86. GRB050824, HETE-2 Observation
  87. GRB 050826: Swift XRT preliminary analysis results
  88. GRB 050826: BAT refined analysis
  89. GRB050826: Swift/UVOT early upper limits
  90. GRB 050826: Swift XRT position
  91. GRB050826: Swift-BAT detection of a long burst
  92. GRB050824: MASTER final analysis of the OT observations
  93. Possible GRB050825:MASTER optical observations
  94. Swift-BAT trigger 152038 is definitely not a GRB
  95. GRB050824: CORRECTION to UVOT observing times
  96. Swift-BAT trigger 152038 is probably not a GRB
  97. GRB050824: Swift/UVOT detection of fading afterglow
  98. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  99. GRB 050824: XRT refined analysis and possible afterglow detection
  100. GRB 050824: BAT refined analysis of a soft weak burst

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