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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"

21468 results found.

  1. GRB 071006 Swift-BAT detection of a burst
  2. GRB071008: IAC80 observation
  3. GRB 071008: Swift detection of a burst
  4. GRB 071003: XRT refined analysis
  5. GRB070920A: MAGIC telescope GeV observation
  6. Radio detection of GRB 071003 with the VLA
  7. GRB 070810B: further XRT analysis
  8. Konus-Wind observation of GRB 071003
  9. GRB 071003: Swift XRT position
  10. GRB 071003, Swift-BAT refined analysis
  11. GRB 071003: MARGE Observations
  12. GRB 071003 Optical observations
  13. GRB 071003: KAIT optical afterglow observations
  14. GRB 071003: Swift detection of a bright burst
  15. GRB 070714B: host galaxy spectroscopic redshift
  16. GRB 071001: Swift-XRT Team refined analysis
  17. GRB 071001, Swift-BAT refined analysis
  18. Faulkes Telescope South observations of GRB 071001
  19. GRB 071001: Swift detection of a burst
  20. VLA observation of GRB 070923
  21. Disregard the Swift-XRT Notices today
  22. GRB070925: Swift-XRT Afterglow confirmation
  23. GRB 070925: Gemini South Imaging
  24. GRB070925: Swift-XRT Position
  25. Update on Swift Status
  26. GRB 070920B: ROTSE-III Early Optical Limits
  27. Recent SGR1806-20 Activity
  28. GRB 070923, Swift-BAT refined analysis
  29. GRB 070920B: XRT observations
  30. GRB 070923: Swift detection of a short hard burst
  31. GRB 070917: Suzaku/WAM observation of the prompt emission
  32. GRB 070920B: TAROT La Silla observatory optical observations
  33. GRB 070917: Confirmation of the X-ray afterglow
  34. GRB 070920B, Swift-BAT refined analysis
  35. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  36. GRB 070920B: NOT optical observations
  37. GRB 070920B: Swift detection of a burst
  38. GRB 070920, Swift-BAT refined analysis
  39. GRB 070920: TAROT Calern observatory optical observations
  40. GRB 070920: Swift detection of a burst
  41. SGR1806-20: Swift-BAT detection of enhanced activity
  42. GRB070917: optical observations
  43. GRB 070917: P60 Observations
  44. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  45. Konus-Wind observation of GRB 070917
  46. Swift Status and XRT Calibration Uncertainties
  47. GRB 070917: Swift-XRT observations
  48. GRB 070917: KAIT optical limits
  49. GRB 070917: R band observations
  50. GRB 070917, Swift-BAT refined analysis
  51. GRB 070917: Swift detection of a bright burst
  52. GRB 070911: Suzaku WAM observation of the prompt emission
  53. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  54. GRB 070809: The Swift evidence for the SHB nature of this burst
  55. GRB 070913: Swift-BAT refined analysis
  56. GRB 070913: Corrected BAT position
  57. GRB 070913: TAROT La Silla observatory optical observations
  58. GRB 070913: Swift detection of a burst
  59. Swift-BAT Notices back to autonomous real-time distribution
  60. GRB 070911: PAIRITEL IR Observations
  61. GRB 070911: Swift XRT refined analysis
  62. GRB 070911, Swift-BAT refined analysis
  63. GRB 070911: Swift detection of a burst
  64. IPN search for a GRB associated with TAROT transient on August 31
  65. Intense burst from SGR 1806-20 detected on September 7
  66. GRB 070810b: Image Subtraction of Multiple Keck Observations
  67. GRB 070824 - Combined SuperAGILE/IPN Localization
  68. GRB 070731: Swift/UVOT Upper Limit
  69. GRB 070805: UVOT afterglow candidate retraction
  70. GRB070810b: optical candidate
  71. GRB 070810A: ROTSE-III Refined Analysis
  72. Swift observatory off line
  73. GRB 070810B : Faulkes Telescope South Observations
  74. GRB 070810B: Keck spectroscopy of possible host galaxies
  75. GRB070810B: Swift/UVOT Upper Limits
  76. GRB 070810B: XRT refined analysis
  77. GRB 070810B, Swift-BAT refined analysis
  78. GRB 070809: Swift/UVOT Corrected Photometry
  79. Swift Alert 070810.8: MASTER optical observation
  80. Swift Trigger 287421: False trigger due to star tracker loss
  81. GRB 070810A: Swift-BAT refined analysis
  82. GRB 070809: Swift/UVOT Upper Limits
  83. GRB 070810B: Swift detection of a short burst
  84. VLA upper limit on the short hard burst GRB 070729
  85. No radio detection in superAGILE burst 070724B
  86. GRB 070809: Keck Imaging
  87. GRB 070810: Swift-XRT Team Refined Analysis
  88. GRB 070809: Swift-XRT refined analysis
  89. GRB 070810: enhanced Swift-XRT position
  90. GRB 070810: Swift/UVOT Optical Counterpart
  91. GRB 070810: ROTSE-III Detection of Optical Counterpart
  92. GRB 070810: Swift detection of a burst
  93. GRB 070809, Swift-BAT refined analysis
  94. GRB 070809: Optical Pre-imaging from Palomar
  95. GRB 070808: Swift/UVOT upper limits
  96. GRB 070809: ROTSE-III Optical Limits
  97. GRB 070809: Swift detection of a short burst
  98. GRB 070808 : Faulkes Telescope South Observations
  99. GCN Swift XRT update position notices and enhanced position circulars
  100. GRB 070808: Swift XRT refined analysis

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