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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"

27041 results found.

  1. GRB 050922C: NOT optical observations
  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. Possible GRB 050922 detected by INTEGRAL
  9. GRB050916: Swift/UVOT Upper Limits
  10. GRB 050916: Swift-BAT refined analysis
  11. Swift-BAT trigger 155764 is not a GRB
  12. Swift-BAT trigger 155764 is probably not a GRB
  13. Swift trigger 155764: bad XRT centroid
  14. Swift-BAT trigger 155535 is definitely not a GRB
  15. GRB050916 : Swift-XRT refined analysis
  16. GRB 050916: XRT position
  17. GRB 050915B: Swift-BAT refined analysis
  18. GRB 050915B: Swift/UVOT Upper Limits
  19. GRB050916: Swift-BAT detection of a long weak burst
  20. GRB050915B: Swift-BAT detection of a long bright burst
  21. GRB050915: Swift/UVOT upper limits
  22. GRB 050915: KAIT optical limit
  23. GRB 050915: IR Observations
  24. GRB 050915: Swift XRT refined analysis
  25. GRB 050915: Swift-BAT refined analysis
  26. GRB050915: XRT position
  27. GRB 050915: ROTSE-III optical limits
  28. GRB 050915: Swift detection of a GRB
  29. GRB050911: Upper limit on X-ray afterglow
  30. Swift-BAT trigger 155072 ground analysis
  31. Swift-BAT trigger 155072 is probably not a GRB
  32. GRB050914: XRT position probably due to cosmic ray
  33. Swift is in normal operation
  34. GRB050911: Swift UVOT followup observations
  35. GRB050911: Swift-XRT position
  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. GRB 050910a: TAROT early optical limits
  41. GRB050908: Swift/UVOT Early upper limits
  42. GRB050908 : Swift-XRT refined analysis
  43. GRB 050908: Swift-BAT refined analysis
  44. GRB 050908: Optical observations
  45. Gemini Spectroscopy of GRB 050908
  46. GRB 050908 : Swift XRT position
  47. GRB 050908: KAIT observations
  48. GRB 050908: Swift detection of a burst
  49. Swift trigger 154073 is not a GRB
  50. GRB 050906: MARGE Optical Limits
  51. GRB 050906: Swift-BAT refined analysis
  52. GRB050906: P60 Observations
  53. GRB 050906: Bright galaxy in BAT error box
  54. GRB 050906: Swift/BAT Detection of a possible burst
  55. GRB 050904: Swift/UVOT observations
  56. GRB 050904: early Swift XRT analysis results
  57. GRB 050904: BAT refined analysis of partial data set
  58. GRB050904: P60 Observations
  59. GRB 050904: TAROT optical limits
  60. GRB050904: Swift-BAT detection of a probable burst
  61. Swift-BAT triggers 153461-153465 are not GRBs
  62. Retraction of Swift-BAT trigger #153355
  63. Swift Trigger #152652 is not a GRB
  64. GRB050827: Swift/UVOT upper limits
  65. GRB 050827: Optical Limit
  66. GRB050820A: RTT150 optical observations
  67. GRB050827: RTT150 optical observations
  68. GRB 050827: Swift-BAT refined analysis
  69. GRB050827: Swift-BAT detection of a burst
  70. GRB 050826: Optical Candidate
  71. GRB 050826: Swift XRT preliminary analysis results
  72. GRB 050826: BAT refined analysis
  73. GRB050826: Swift/UVOT early upper limits
  74. GRB 050826: Swift XRT position
  75. GRB050826: Swift-BAT detection of a long burst
  76. GRB050824: MASTER final analysis of the OT observations
  77. Possible GRB050825:MASTER optical observations
  78. Swift-BAT trigger 152038 is definitely not a GRB
  79. GRB050824: CORRECTION to UVOT observing times
  80. Swift-BAT trigger 152038 is probably not a GRB
  81. GRB050824: Swift/UVOT detection of fading afterglow
  82. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  83. GRB 050824: XRT refined analysis and possible afterglow detection
  84. GRB 050824: BAT refined analysis of a soft weak burst
  85. GRB050824: MASTER:OT decay
  86. GRB050824: MASTER observation OT
  87. GRB050805a: MASTER optical candidat
  88. GRB 050824: ROTSE-III Optical Limits
  89. GRB050824: Swift-BAT detection of a burst
  90. GRB050820A: RTT150 optical observations
  91. VLT/UVES spectroscopy of GRB050820
  92. GRB050822: Swift/UVOT upper limits
  93. GRB 050822: Swift-BAT refined analysis
  94. GRB 050820a - corrections to GCN 3846
  95. Swift/UVOT UV Photometry of GRB 050820B
  96. GRB 050822: ROTSE-III Prompt Optical Limits
  97. GRB 050822: Swift detection of a long burst
  98. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  99. GRB 050820a: NIR Observations by WIRO
  100. GRB 050820B: Swift XRT position

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