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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"

19538 results found.

  1. GRB050915: Swift/UVOT upper limits
  2. GRB 050915: KAIT optical limit
  3. GRB 050915: IR Observations
  4. GRB 050915: Swift XRT refined analysis
  5. GRB 050915: Swift-BAT refined analysis
  6. GRB050915, optical observations
  7. GRB050915: XRT position
  8. GRB 050915: ROTSE-III optical limits
  9. GRB 050915: Swift detection of a GRB
  10. GRB050911: Upper limit on X-ray afterglow
  11. Swift-BAT trigger 155072 ground analysis
  12. Swift-BAT trigger 155072 is probably not a GRB
  13. GRB050914: XRT position probably due to cosmic ray
  14. Swift is in normal operation
  15. GRB050911: Swift UVOT followup observations
  16. GRB 050911, optical content of Swift/XRT error box
  17. GRB050911: Swift-XRT position
  18. GRB 050911, optical observations
  19. GRB 050911: Swift-BAT refined analysis
  20. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  21. GRB050911: Swift-BAT detection of a long burst
  22. GRB050908: detection of Swift/UVOT optical counterpart
  23. RBO GRB 050908 observations
  24. WIRO observations in I of GRB 050908
  25. GRB 050906: Possible X-ray Counterpart
  26. GRB050908: Swift/UVOT Early upper limits
  27. GRB050908 : Swift-XRT refined analysis
  28. GRB 050908: Swift-BAT refined analysis
  29. GRB 050908: Optical observations
  30. Gemini Spectroscopy of GRB 050908
  31. GRB 050908 : Swift XRT position
  32. GRB 050908: KAIT observations
  33. GRB 050908: P60 Confirmation of Optical Afterglow
  34. GRB 050908: Swift detection of a burst
  35. Swift trigger 154073 is not a GRB
  36. GRB050904: CrAO optical observations
  37. GRB 050904 BAT refined analysis of complete data set
  38. GRB 050906: MARGE Optical Limits
  39. GRB 050906: Swift-BAT refined analysis
  40. GRB 050906: Swift XRT upper limit
  41. GRB050906: P60 Observations
  42. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  43. GRB 050906: Bright galaxy in BAT error box
  44. GRB 050906: Swift/BAT Detection of a possible burst
  45. GRB 050904: Swift/UVOT observations
  46. GRB 050904: early Swift XRT analysis results
  47. GRB 050904: BAT refined analysis of partial data set
  48. GRB050904: P60 Observations
  49. GRB 050904: TAROT optical limits
  50. GRB050904: Swift-BAT detection of a probable burst
  51. Swift-BAT triggers 153461-153465 are not GRBs
  52. Retraction of Swift-BAT trigger #153355
  53. GRB 050824: MDM Observations
  54. GRB 050827: Swift XRT preliminary analysis results
  55. Swift Trigger #152652 is not a GRB
  56. GRB050827: Swift/UVOT upper limits
  57. GRB 050827: Optical Limit
  58. GRB 050827: XRT possible afterglow detection
  59. GRB050827: RTT150 optical observations
  60. GRB 050827: Swift-BAT refined analysis
  61. GRB050827: Swift-BAT detection of a burst
  62. GRB 050826: Optical Candidate
  63. GRB050824, HETE-2 Observation
  64. GRB 050826: Swift XRT preliminary analysis results
  65. GRB 050826: BAT refined analysis
  66. GRB050826: Swift/UVOT early upper limits
  67. GRB050824: First 2 hours of power low optical decay?
  68. GRB 050826: Swift XRT position
  69. GRB050826: Swift-BAT detection of a long burst
  70. GRB050824: MASTER final analysis of the OT observations
  71. Possible GRB050825:MASTER optical observations
  72. Swift-BAT trigger 152038 is definitely not a GRB
  73. GRB050824: CORRECTION to UVOT observing times
  74. Swift-BAT trigger 152038 is probably not a GRB
  75. GRB050824: Swift/UVOT detection of fading afterglow
  76. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  77. GRB050824, I-band imaging
  78. GRB 050822: refined XRT analysis
  79. GRB 050824: XRT refined analysis and possible afterglow detection
  80. GRB 050824: BAT refined analysis of a soft weak burst
  81. GRB050824: MASTER:OT decay
  82. GRB050824: MASTER observation OT
  83. GRB050805a: MASTER optical candidat
  84. GRB 050824: ROTSE-III Optical Limits
  85. GRB050824: Swift-BAT detection of a burst
  86. GRB050822: Swift/UVOT upper limits
  87. GRB 050820A BAT observations of second, larger episode of emission
  88. GRB 050822: Swift-BAT refined analysis
  89. GRB 050820a - corrections to GCN 3846
  90. Swift/UVOT UV Photometry of GRB 050820B
  91. GRB 050822: ROTSE-III Prompt Optical Limits
  92. GRB 050822: Swift detection of a long burst
  93. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  94. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  95. GRB050820a BVRcIc field photometry
  96. GRB050820B XMM-Newton observation
  97. GRB 050820a: NIR Observations by WIRO
  98. GRB 050820B: Swift XRT position
  99. GRB050820B: Refined analysis of the Swift-BAT burst
  100. GRB050820B: BAT-Swift detection of a bright GRB

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