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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"

27776 results found.

  1. GRB050925: Swift/XRT limits
  2. GRB/SGR 050925: IR Observations
  3. GRB050922C - Swift UVOT preliminary analysis
  4. GRB 050925: WSRT Radio Observations
  5. GRB050925: Swift UVOT upper limits
  6. Refined analysis of the Swift-BAT soft short burst
  7. GRB050925: Faulkes Telescope North R-band limit
  8. GRB050925: Swift-BAT detection of a short burst
  9. GRB 050922B: Correction to BAT refined analysis, longer burst
  10. GRB050922B: refined XRT analysis
  11. Konus-Wind observation of GRB 050922C
  12. GRB 050922C: Refined redshift
  13. GRB050922B: Swift UVOT early upper limits.
  14. GRB 050922B: optical limit
  15. GRB 050922C: Swift XRT refined analysis
  16. HETE Fregate observations of GRB 050922C
  17. GRB 050922C: Swift-BAT refined analysis
  18. GRB 050922B: Swift-BAT refined analysis
  19. GRB050922C: optical observations
  20. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  21. GRB 050922C: optical obserations
  22. GRB 050922C: NOT optical observations
  23. GRB 050922A: Analysis of Swift/XRT TOO observation
  24. GRB 050922C: Swift detection of a bright burst
  25. GRB 050922C: ROTSE-IIId Refined Analysis
  26. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  27. GRB 050922B: ROTSE-III Optical Limits
  28. GRB 050922B,optical observation
  29. GRB050922B: Swift-BAT detection of a weak long burst
  30. GRB050918: Possible Swift/XRT detected afterglow
  31. GRB050820B: analysis of the XMM-Newton observation
  32. GRB050916: Swift/UVOT Upper Limits
  33. GRB 050916: Swift-BAT refined analysis
  34. Swift-BAT trigger 155764 is not a GRB
  35. Swift-BAT trigger 155764 is probably not a GRB
  36. Swift trigger 155764: bad XRT centroid
  37. Swift-BAT trigger 155535 is definitely not a GRB
  38. GRB050916 : Swift-XRT refined analysis
  39. GRB 050916: XRT position
  40. GRB 050915b, SMARTS optical/IR observations of the XRT position
  41. GRB 050915B: Swift-BAT refined analysis
  42. GRB 050915B: Swift/UVOT Upper Limits
  43. GRB050916: Swift-BAT detection of a long weak burst
  44. GRB 050915a: IR Transient
  45. GRB 050915B: XRT position
  46. GRB050915B: Swift-BAT detection of a long bright burst
  47. GRB050915: Swift/UVOT upper limits
  48. GRB 050915: KAIT optical limit
  49. GRB 050915: IR Observations
  50. GRB 050915: Swift XRT refined analysis
  51. GRB 050915: Swift-BAT refined analysis
  52. GRB050915, optical observations
  53. GRB050915: XRT position
  54. GRB 050915: ROTSE-III optical limits
  55. GRB 050915: Swift detection of a GRB
  56. GRB050911: Upper limit on X-ray afterglow
  57. Swift-BAT trigger 155072 ground analysis
  58. Swift-BAT trigger 155072 is probably not a GRB
  59. GRB050914: XRT position probably due to cosmic ray
  60. Swift is in normal operation
  61. GRB050911: Swift UVOT followup observations
  62. GRB 050911, optical content of Swift/XRT error box
  63. GRB050911: Swift-XRT position
  64. GRB 050911, optical observations
  65. GRB 050911: Swift-BAT refined analysis
  66. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  67. GRB050911: Swift-BAT detection of a long burst
  68. GRB050908: detection of Swift/UVOT optical counterpart
  69. RBO GRB 050908 observations
  70. WIRO observations in I of GRB 050908
  71. GRB 050906: Possible X-ray Counterpart
  72. GRB050908: Swift/UVOT Early upper limits
  73. GRB050908 : Swift-XRT refined analysis
  74. GRB 050908: Swift-BAT refined analysis
  75. GRB 050908: Optical observations
  76. Gemini Spectroscopy of GRB 050908
  77. GRB 050908: spectroscopic redshift
  78. GRB 050908 : Swift XRT position
  79. GRB 050908: KAIT observations
  80. GRB 050908: P60 Confirmation of Optical Afterglow
  81. GRB 050908: Swift detection of a burst
  82. Swift trigger 154073 is not a GRB
  83. GRB050904: CrAO optical observations
  84. GRB 050904 BAT refined analysis of complete data set
  85. GRB 050906: MARGE Optical Limits
  86. GRB 050906: Swift-BAT refined analysis
  87. GRB 050906: Swift XRT upper limit
  88. GRB050906: P60 Observations
  89. GRB 050904: BOOTES early R-band observation
  90. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  91. GRB 050906: Bright galaxy in BAT error box
  92. GRB 050906: Swift/BAT Detection of a possible burst
  93. GRB 050904: Swift/UVOT observations
  94. GRB 050904: early Swift XRT analysis results
  95. GRB 050904: BAT refined analysis of partial data set
  96. GRB050904: Optical Observations
  97. GRB 050904: SOAR/PROMPT Observations
  98. GRB050904: P60 Observations
  99. GRB 050904: TAROT optical limits
  100. GRB050904: Swift-BAT detection of a probable burst

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