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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"

18399 results found.

  1. GRB 050509B: Swift/XRT refined analysis
  2. GRB050509a: Swift UVOT observations
  3. GRB 050509b: Optical observations
  4. GRB 050509b: Possible Optical Counterpart
  5. GRB 050509A: Optical observations
  6. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  7. GRB 050509b: optical observations
  8. GRB 050509b: Swift XRT Position
  9. GRB 050509B: ROTSE-III Optical Limits
  10. Swift Detection of GRB050509b: A short duration burst
  11. GRB 050509a: Swift XRT Position
  12. Swift Detection of the Burst GRB050509
  13. Swift-BAT detection of GRB 050507
  14. GRB 050505: early time observations
  15. GRB 050505 - Faulkes Telescope North observations
  16. GRB 050502a: Swift XRT Upper Limit
  17. GRB 050505, simultaneous optical observation
  18. GRB 050505: Further Swift UVOT observations.
  19. GRB050416A : 1 GHz limit from GMRT
  20. GRB 050505 UVOT
  21. GRB 050505: Swift XRT Position
  22. GRB050505 Swift-BAT refined analysis
  23. GRB 050416b:Swift XRT afterglow upper limits
  24. GRB 050416b:Swift XRT afterglow upper limits
  25. Swift-BAT detection of GRB050505
  26. GRB 050504: Swift XRT position
  27. Swift UVOT observation of GRB 050504
  28. GRB 050502b, V band Observations
  29. GRB050502B Swift-BAT refined analysis
  30. GRB050502B: I band source in XRT error circle
  31. Swift UVOT refined analysis
  32. Retraction of Swift-BAT trigger 116145
  33. GRB 050502b : optical observation at Lulin observatory
  34. GRB 050502b: Swift XRT Position
  35. GRB050502B: Optical Limits from ANU 1m
  36. Swift Detection of the Bright Burst GRB050502b
  37. GRB050502: ANU 1m optical Observations
  38. Swift-BAT Trigger 115881 is not a real GRB
  39. Swift/BAT possible detection of a weak burst GRB050430
  40. GRB 050401: Rc observation
  41. GRB050416a: Radio Detection
  42. GRB 050422: Swift-UVOT observation
  43. GRB 050422: Swift-BAT refined analysis
  44. GRB 050422: Swift XRT Position
  45. Swift Detection of GRB 050422
  46. GRB 050421: SLOTIS observations
  47. GRB050421: Radio Observations
  48. GRB050421: Radio Observations
  49. GRB 050421: Swift-UVOT observation
  50. GRB 050421: Swift-BAT refined analysis
  51. GRB 050421: ROTSE-III Optical Limits
  52. GRB 050421: early Swift XRT analysis results
  53. GRB 050421: BOOTES-2 simultaneous optical observations
  54. GRB 050421: Optical observations at the INT
  55. Swift Detection of GRB050421
  56. GRB 050416b: Tentative Swift XRT Position
  57. GRB050326: analysis of the XMM-Newton observation
  58. GRB 050418: Swift-BAT refined analysis
  59. Swift-BAT detection of the bright and long GRB 050418
  60. GRB 050416B: optical observations
  61. GRB 050416b: Swift-BAT refined analysis
  62. GRB 050416: Swift/UVOT refined analysis
  63. Swift-BAT detection of GRB 050416b
  64. GRB050412: Radio Observations
  65. GRB 050416: Swift/UVOT detection of afterglow emission
  66. GRB050416: Refined Swift-XRT analysis
  67. GRB050416: Maidanak optical observations
  68. GRB 050416: Swift-BAT refined analysis
  69. GRB 050416,optical observation
  70. GRB 050416: KAIT observations
  71. GRB 050416: Swift XRT Position
  72. GRB 050416: Radio observations
  73. Confirmation of OT for GRB050416
  74. GRB050416: P60 Afterglow Candidate
  75. Swift BAT/XRT Detection of GRB 050416
  76. GRB 050412: Subaru observations
  77. GRB 050412: optical limit
  78. GRB 050412: optical observations
  79. GRB 050408: refined XRT analysis, no jet break seen yet
  80. GRB 050412: early Swift XRT analysis results
  81. GRB 050412: Swift-BAT refined analysis
  82. GRB 050412: ANU 2.3m observations
  83. GRB 050412: Early Optical/Ultraviolet Observations with
  84. GRB 050412: retraction of UVOT transient report
  85. GRB 050412: UVOT transient not in XRT error circle
  86. GRB 050412: Swift XRT Position
  87. GRB050412: optical limit before and during GRB
  88. GRB050412: ROTSE-III Optical Limits
  89. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  90. GRB 050412: IR Observations
  91. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  92. GRB 050410, optical observations
  93. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  94. GRB 050410 R band Optical Observations
  95. GRB050410 : Null detection report
  96. GRB 050410, optical observations
  97. GRB050410: Radio Observations
  98. GRB 050408: Swift XRT measurement of possible jet break
  99. GRB050410: MASTER optical observations
  100. GRB 050410: Early observations with Swift-UVOT

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