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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"

28882 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: optical obserations
  7. GRB 050922C: NOT optical observations
  8. GRB 050922C: Swift detection of a bright burst
  9. GRB 050922C: ROTSE-IIId Refined Analysis
  10. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  11. GRB 050922B: ROTSE-III Optical Limits
  12. GRB 050922B,optical observation
  13. GRB050922B: Swift-BAT detection of a weak long burst
  14. Possible GRB 050922 detected by INTEGRAL
  15. GRB050916: Swift/UVOT Upper Limits
  16. GRB 050916: Swift-BAT refined analysis
  17. Swift-BAT trigger 155764 is not a GRB
  18. Swift-BAT trigger 155764 is probably not a GRB
  19. Swift trigger 155764: bad XRT centroid
  20. Swift-BAT trigger 155535 is definitely not a GRB
  21. GRB050916 : Swift-XRT refined analysis
  22. GRB 050916: XRT position
  23. GRB 050915B: Swift-BAT refined analysis
  24. GRB 050915B: Swift/UVOT Upper Limits
  25. GRB050916: Swift-BAT detection of a long weak burst
  26. GRB050915B: Swift-BAT detection of a long bright burst
  27. GRB050915: Swift/UVOT upper limits
  28. GRB 050915: KAIT optical limit
  29. GRB 050915: IR Observations
  30. GRB 050915: Swift XRT refined analysis
  31. GRB 050915: Swift-BAT refined analysis
  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. Swift is in normal operation
  40. GRB050911: Swift UVOT followup observations
  41. GRB050911: Swift-XRT position
  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. GRB050908: Swift/UVOT Early upper limits
  48. GRB050908 : Swift-XRT refined analysis
  49. GRB 050908: Swift-BAT refined analysis
  50. GRB 050908: Optical observations
  51. Gemini Spectroscopy of GRB 050908
  52. GRB 050908 : Swift XRT position
  53. GRB 050908: KAIT observations
  54. GRB 050908: Swift detection of a burst
  55. Swift trigger 154073 is not a GRB
  56. GRB 050906: MARGE Optical Limits
  57. GRB 050906: Swift-BAT refined analysis
  58. GRB050906: P60 Observations
  59. GRB 050906: Bright galaxy in BAT error box
  60. GRB 050906: Swift/BAT Detection of a possible burst
  61. GRB 050904: Swift/UVOT observations
  62. GRB 050904: early Swift XRT analysis results
  63. GRB 050904: BAT refined analysis of partial data set
  64. GRB050904: P60 Observations
  65. GRB 050904: TAROT optical limits
  66. GRB050904: Swift-BAT detection of a probable burst
  67. Swift-BAT triggers 153461-153465 are not GRBs
  68. Retraction of Swift-BAT trigger #153355
  69. Swift Trigger #152652 is not a GRB
  70. GRB050827: Swift/UVOT upper limits
  71. GRB 050827: Optical Limit
  72. GRB050820A: RTT150 optical observations
  73. GRB050827: RTT150 optical observations
  74. GRB 050827: Swift-BAT refined analysis
  75. GRB050827: Swift-BAT detection of a burst
  76. GRB 050826: Optical Candidate
  77. GRB 050826: Swift XRT preliminary analysis results
  78. GRB 050826: BAT refined analysis
  79. GRB050826: Swift/UVOT early upper limits
  80. GRB 050826: Swift XRT position
  81. GRB050826: Swift-BAT detection of a long burst
  82. GRB050824: MASTER final analysis of the OT observations
  83. Possible GRB050825:MASTER optical observations
  84. Swift-BAT trigger 152038 is definitely not a GRB
  85. GRB050824: CORRECTION to UVOT observing times
  86. Swift-BAT trigger 152038 is probably not a GRB
  87. GRB050824: Swift/UVOT detection of fading afterglow
  88. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  89. GRB 050824: XRT refined analysis and possible afterglow detection
  90. GRB 050824: BAT refined analysis of a soft weak burst
  91. GRB050824: MASTER:OT decay
  92. GRB050824: MASTER observation OT
  93. GRB050805a: MASTER optical candidat
  94. GRB 050824: ROTSE-III Optical Limits
  95. GRB050824: Swift-BAT detection of a burst
  96. GRB050820A: RTT150 optical observations
  97. VLT/UVES spectroscopy of GRB050820
  98. GRB050822: Swift/UVOT upper limits
  99. GRB 050822: Swift-BAT refined analysis
  100. GRB 050820a - corrections to GCN 3846

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