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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').
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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"

21458 results found.

  1. GRB 071003: MARGE Observations
  2. GRB 071003 Optical observations
  3. GRB 071003: KAIT optical afterglow observations
  4. GRB 071003: Swift detection of a bright burst
  5. GRB 070714B: host galaxy spectroscopic redshift
  6. GRB 071001: Swift-XRT Team refined analysis
  7. GRB 071001, Swift-BAT refined analysis
  8. Faulkes Telescope South observations of GRB 071001
  9. GRB 071001: Swift detection of a burst
  10. VLA observation of GRB 070923
  11. Disregard the Swift-XRT Notices today
  12. GRB070925: Swift-XRT Afterglow confirmation
  13. GRB 070925: Gemini South Imaging
  14. GRB070925: Swift-XRT Position
  15. Update on Swift Status
  16. GRB 070920B: ROTSE-III Early Optical Limits
  17. Recent SGR1806-20 Activity
  18. GRB 070923, Swift-BAT refined analysis
  19. GRB 070920B: XRT observations
  20. GRB 070923: Swift detection of a short hard burst
  21. GRB 070917: Suzaku/WAM observation of the prompt emission
  22. GRB 070920B: TAROT La Silla observatory optical observations
  23. GRB 070917: Confirmation of the X-ray afterglow
  24. GRB 070920B, Swift-BAT refined analysis
  25. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  26. GRB 070920B: NOT optical observations
  27. GRB 070920B: Swift detection of a burst
  28. GRB 070920, Swift-BAT refined analysis
  29. GRB 070920: TAROT Calern observatory optical observations
  30. GRB 070920: Swift detection of a burst
  31. SGR1806-20: Swift-BAT detection of enhanced activity
  32. GRB070917: optical observations
  33. GRB 070917: P60 Observations
  34. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  35. Konus-Wind observation of GRB 070917
  36. Swift Status and XRT Calibration Uncertainties
  37. GRB 070917: Swift-XRT observations
  38. GRB 070917: KAIT optical limits
  39. GRB 070917: R band observations
  40. GRB 070917, Swift-BAT refined analysis
  41. GRB 070917: Swift detection of a bright burst
  42. GRB 070911: Suzaku WAM observation of the prompt emission
  43. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  44. GRB 070809: The Swift evidence for the SHB nature of this burst
  45. GRB 070913: Swift-BAT refined analysis
  46. GRB 070913: Corrected BAT position
  47. GRB 070913: TAROT La Silla observatory optical observations
  48. GRB 070913: Swift detection of a burst
  49. Swift-BAT Notices back to autonomous real-time distribution
  50. GRB 070911: PAIRITEL IR Observations
  51. GRB 070911: Swift XRT refined analysis
  52. GRB 070911, Swift-BAT refined analysis
  53. GRB 070911: Swift detection of a burst
  54. IPN search for a GRB associated with TAROT transient on August 31
  55. Intense burst from SGR 1806-20 detected on September 7
  56. GRB 070810b: Image Subtraction of Multiple Keck Observations
  57. GRB 070824 - Combined SuperAGILE/IPN Localization
  58. GRB 070731: Swift/UVOT Upper Limit
  59. GRB 070805: UVOT afterglow candidate retraction
  60. GRB070810b: optical candidate
  61. GRB 070810A: ROTSE-III Refined Analysis
  62. Swift observatory off line
  63. GRB 070810B : Faulkes Telescope South Observations
  64. GRB 070810B: Keck spectroscopy of possible host galaxies
  65. GRB070810B: Swift/UVOT Upper Limits
  66. GRB 070810B: XRT refined analysis
  67. GRB 070810B, Swift-BAT refined analysis
  68. GRB 070809: Swift/UVOT Corrected Photometry
  69. Swift Alert 070810.8: MASTER optical observation
  70. Swift Trigger 287421: False trigger due to star tracker loss
  71. GRB 070810A: Swift-BAT refined analysis
  72. GRB 070809: Swift/UVOT Upper Limits
  73. GRB 070810B: Swift detection of a short burst
  74. VLA upper limit on the short hard burst GRB 070729
  75. No radio detection in superAGILE burst 070724B
  76. GRB 070809: Keck Imaging
  77. GRB 070810: Swift-XRT Team Refined Analysis
  78. GRB 070809: Swift-XRT refined analysis
  79. GRB 070810: enhanced Swift-XRT position
  80. GRB 070810: Swift/UVOT Optical Counterpart
  81. GRB 070810: ROTSE-III Detection of Optical Counterpart
  82. GRB 070810: Swift detection of a burst
  83. GRB 070809, Swift-BAT refined analysis
  84. GRB 070809: Optical Pre-imaging from Palomar
  85. GRB 070808: Swift/UVOT upper limits
  86. GRB 070809: ROTSE-III Optical Limits
  87. GRB 070809: Swift detection of a short burst
  88. GRB 070808 : Faulkes Telescope South Observations
  89. GCN Swift XRT update position notices and enhanced position circulars
  90. GRB 070808: Swift XRT refined analysis
  91. GRB 070808, Swift-BAT refined analysis
  92. GRB 070808: OPTIMA-Burst optical upper limit
  93. GRB 070808: Xinglong TNT optical Upper Limit
  94. GRB070808 - SDSS Pre-Burst Observations
  95. GRB 070808: ROTSE-III Optical Limits
  96. GRB 070808: Swift detection of a burst
  97. GRB070805 XRT and UVOT afterglow candidate
  98. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  99. Swift/UVOT observations of GRB070805
  100. GRB 070805, Swift-BAT refined analysis

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